Accepted Manuscript Active Clearance of Chest Drainage Catheters Reduces Retained Blood J. Sirch, MD, M. Ledwon, MD, T. Pu¨ski, MD, E.M. Boyle, MD, S. Pfeiffer, MD, T. Fischlein, MD PII:
S0022-5223(15)01970-4
DOI:
10.1016/j.jtcvs.2015.10.015
Reference:
YMTC 10050
To appear in:
The Journal of Thoracic and Cardiovascular Surgery
Received Date: 20 November 2014 Revised Date:
1 October 2015
Accepted Date: 10 October 2015
Please cite this article as: Sirch J, Ledwon M, Pu¨ski T, Boyle E, Pfeiffer S, Fischlein T, Active Clearance of Chest Drainage Catheters Reduces Retained Blood, The Journal of Thoracic and Cardiovascular Surgery (2015), doi: 10.1016/j.jtcvs.2015.10.015. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Active Clearance of Chest Drainage Catheters Reduces Retained Blood
2 Authors: J Sirch, MD.1, M Ledwon, MD1, T Püski, MD1, EM Boyle, MD.2, S Pfeiffer,
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MD1, T Fischlein, MD1
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5 Institutions:
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Paracelsus Medical University, Nuremberg, Germany,
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Dept. of Cardiac Surgery, Kllinikum Nürnberg,
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St. Charles Medical Center, Bend, Oregon, United States
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Funding Source: Funded in part by a grant from ClearFlow, Inc.
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Disclosures: Dr. Boyle is a founding shareholder and board member of ClearFlow, Inc.
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and is paid a consulting fee for his work. Drs. Sirch, Ledwon, Puski, Pfeiffer and
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Fischlein have no potential conflicts of interest.
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Address for Reprints:
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Prof. Dr. Theodor Fischlein
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Dept. of Cardiac Surgery, Klinikum Nürnberg
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Paracelsus Medical University
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Breslauer Str. 201
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90471 Nuremberg, Germany
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Abstract:
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Objectives: Chest tubes are utilized to clear blood from around the heart and lungs
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after heart surgery, but they can obstruct with clot, leading to retained blood syndrome
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(RBS). This study sought to examine the frequency of RBS and associated morbidity,
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and to determine the impact of a preventative active chest tube clearance protocol on
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these outcomes. Methods: A multidisciplinary team developed a simple protocol to
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institute active tube clearance (ATC) to preventatively clear chest tubes of clot in the first
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24 hours after heart surgery. An extensive educational in-service was performed before
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universal implementation (phase 1). We retrospectively compared data collected
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prospectively from 1,849 patients before (phase 0) with data from 256 patients collected
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prospectively after universal implementation (phase 2), and then used propensity
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matching for outcomes assessment. Results: In propensity-matched patients, 19.9%
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of patients had interventions for RBS (phase 0). After the implementation of ATC
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(phase 2), the percent of patients with interventions for RBS was reduced to 11.3%,
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representing a 43% reduction in RBS (P = 0.0087). These patients had a 33% reduced
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incidence of postoperative atrial fibrillation (POAF) from 30% (78/256) in phase 0 to 20%
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(53/256) in phase 2. (P = 0.013). Conclusions: ATC is associated with a reduced
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need for interventions for RBS and POAF. Our findings underscore the importance of
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maintaining chest tube patency in the early hours after cardiac surgery.
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Central Message: Active tube clearance reduces interventions for RBS and POAF,
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underscoring the importance of maintaining chest tube patency after cardiac surgery.
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Perspective Statement: All patients require chest tubes to drain shed blood after heart
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surgery, yet clogging of chest tubes is common. We studied a protocol to maintain
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chest tube patency with active tube clearance and demonstrated an associated
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reduction in retained blood syndrome and postoperative atrial fibrillation. Our findings
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underscore the importance of maintaining chest tube patency in outcomes after cardiac
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surgery.
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Introduction
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Postoperative bleeding is common to some degree in nearly all patients in the early
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hours after heart surgery (1). To obtain adequate evacuation, chest tubes are utilized to
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drain shed blood and prevent retained collections around the heart and lungs (2). Chest
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tubes, however, can obstruct with clot, impairing their evacuation capacity. Recently, a
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prospective observational study quantified that 36% of chest tubes obstruct after heart
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surgery, often in the internal portion inside the patients where the obstruction goes
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unnoticed to the care givers (3). We hypothesized that chest tube obstruction might
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contribute to retained blood syndrome (RBS) after cardiac surgery. To study this
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hypothesis we initiated a continuous quality improvement process to assess the
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incidence of RBS, then develop and implement a universal protocol utilizing active tube
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clearance (ATC) to periodically clear the internal lumen of chest tubes.
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Materials and Methods
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Data was collected from our institutional cardiac surgery database. Structured data
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elements are routinely prospectively collected and available for retrospective analysis.
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Operative variables included the type of surgery (CABG, Valve, CABG+Valve, Other)
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and re operative status. Procedures in the “Other” category included isolated ascending
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and aortic arch procedures. The primary outcomes measured were interventions for
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RBS, a composite outcome consisting of any of the following interventions: take back
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for re-exploration for hemorrhage; pericardial interventions (pericardial window or
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pericardiocentesis); and pleural interventions for hemothorax, pneumothorax or
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effusions. Patients that had interventions for more than one component of RBS were
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only counted once. Patients that had the diagnosis of pleural or pericardial effusion or
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hemothorax or hemopneumothorax but did not undergo a specific invasive intervention
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were excluded. Secondary outcomes included postoperative atrial fibrillation (POAF),
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cardiac arrest, permanent stroke, postoperative hospital length of stay (LOS), and the
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total chest tube drainage volume (mL). All patients were fitted with at least one 28 Fr
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chest tube in the anterior mediastinum. We do not routinely open the pleura to harvest
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the mammary artery, but when it happens, the surgeons place a pleural 28 Fr chest
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tube. Rarely, a retro cardiac 28 Fr chest tube is placed. Blake or channel type drains
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were not used in any patient in this study. All patients were treated with tranexamic
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acid. An institutional trigger to transfuse for a hemoglobin of 7.5 g/dL to 8 g/dL was
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adhered to in all phases of this study.
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From January 1, 2011 to June 11, 2014, 3,226 adult cardiac surgical procedures were
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performed at the Nuremberg Cardiovascular Center. Patients were divided into 4
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phases for analysis.
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Phase 0: Pre ATC Protocol: From January 1, 2011 to December 31, 2012, 1,849
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cardiac surgery procedures were performed. No patients in this group were treated with
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ATC. These patients were divided into those with any one of the RBS interventions
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versus those without to establish a baseline for measurement of clinical outcomes.
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Phase 1: Limited Implementation for ATC Protocol Development, Training and
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Compliance Verification. A multidisciplinary team developed a simple protocol to
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institute active clearance technology (ATC) to clear chest tubes in the first 24 hours after
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heart surgery. The PleuraFlow Active Clearance Technology System (ClearFlow, Inc.,
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Anaheim, CA) is a chest tube clearance apparatus with a mechanism to actively keep 5
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the entire inner diameter of the chest tube clear of obstructing blood clot or fibrinous
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debris (4). Care providers periodically advance a clearance apparatus back and forth
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within the catheter by actuating the shuttle, which couples via a magnet to the clearance
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member to maintain sterility while the tube is cleared.
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Multidisciplinary team meetings were held for protocol development with cardiac surgical
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staff, residents and fellows, anesthesiologists and critical care physicians and cardiac
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ICU nurses. The objective was to develop a simple protocol to implement ATC that
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could be integrated into the workflow. In prior studies, the most common sites for
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bleeding identified at reoperation were the mediastinum, sternum, internal thoracic
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artery bed, and coronary anastomosis sites (5, 6). For sake of simplicity, it was decided
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to use a single ATC unit (28 Fr) in an anterior mediastinal position. After 24 hours, the
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chest tube with ATC was removed, or the chest tube was left in place and the ATC
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pulled back and its use was discontinued. Most were removed by the 2nd postop day.
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Surgeons were allowed to place additional conventional chest tubes at their discretion,
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however in a majority only a single mediastinal ATC was utilized. The protocol
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developed allows for more frequent use early on, when chest tube outputs tend to be
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higher, and less so in subsequent hours, as well as on an as needed basis (Appendix
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A.) (7) The nurses were free to strip and milk the conventional chest tubes as they felt
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were needed. An extensive educational in-service was performed before universal
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implementation for training of all nurses and physician in the ICU with compliance
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verification. This protocol was rolled out in phase 1 starting on January 1, 2013 through
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November 30, 2013 during which time there were 914 heart surgery cases.
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128 Phase 2: Universal Implementation of ATC Protocol. We implemented phase 2 with
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ATC universally in all consecutive patients from December 1, 2013 to March 16, 2014.
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Phase 3: Post Protocol Re-Measurement. In this phase we stopped the universal
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implementation of ATC and returned to using all conventional chest tubes (without ATC)
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and repeated measurement of outcomes (March 18, 2014 to June 11, 2014).
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This study was an investigator-initiated study that was supported in part by a research
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grant from ClearFlow, Inc. The study site investigators had full access to the data, the
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ability to analyze them independently from the sponsor, and sole authority to make the
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final decision regarding publication. ClearFlow, Inc., played no role in the collection of
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data and had no right to approve or disapprove publication of the finished manuscript.
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Measurement and Analysis
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Our institutional Ethics Committee and an independent Ethics Committee Review Board
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approved this study. We compared results from 1,849 patients before (phase 0) with
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256 patients after universal implementation (phase 2), and then the results of stopping
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the protocol in 222 patients (phase 3), to determine the impact of ATC on outcomes.
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258 patients were approached for consent in phase 2, and 256 agreed to provide
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consent to participate. A complete set of data was available from all patients except for
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chest tube drainage (n = 231) and ventilator hours (n = 255) in phase 2.
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Comparisons of categorical variables used a Chi-squared or Fisher's exact test, as 7
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appropriate, while comparisons of continuous variables used Welch's test if the variable
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was symmetrically distributed and Wilcoxon's rank sum test if the variable had a skewed
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distribution. Propensity scoring was utilized to balance the distributions of measured
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potentially confounding baseline covariates using the matchit function from the R
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package MatchIt with 1:1 nearest neighbor matching based on age, gender, operative
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status (urgent or elective), redo status, procedure (CABG, Valve, CABG + Valve, or
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other), and use of anticoagulants. The analysis compared matched pairs using
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McNemar's test for categorical variables, paired T-tests for symmetrically distributed
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variables, and Wilcoxon's signed rank test for skewed continuous variables.
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161 Results:
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The overall incidence of RBS at baseline (Phase 0) was 19.5% (360/1,849). The
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incidence of RBS in phase 0 was not markedly different for surgery types: 18%
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(182/1,011) for CABG only patients, 19% (83/436) for valve surgery patients, 21%
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(55/260) for combined valve/CABG patients, 29% (41/142), 25% (36/142) for patients
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with other types of surgery. Patients in phase 0 and phase 2 were comparable, except
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an increased number of patients with CABG/Valve in phase 0 and slightly fewer NYHA
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Class II and III patients in phase 2. (E Table 1). In phase 2 there was a 42% reduction
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in the primary endpoint of RBS from 19.5% (360/1,849) to 11.3% (29/256). (E-table 2)
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To account for potential differences between phase 0 and phase 2, a propensity score
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model was used to match a sub cohort of patients in phase 0 that were well balanced for
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comorbidities and operative variables with patients in phase 2. After propensity
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matching, 256 of 1,849 patients in phase 0 were selected for comparison with 256 8
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patients in phase 2. Propensity score matching between phase 0 and 2 found
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agreement for 97.7% for gender, 97.3% for operative status, 80.9% for procedures,
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98.1% for the use of anticoagulants, 99.2% for redo status, and 95.7% for an age
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difference less than 5 years. After matching, there were no differences between Phase
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0 and Phase 2 with respect to age, sex, pre op anticoagulation, hematocrit, COPD,
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hypertension, ejection fraction, operative type, elective status, reoperative status,
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cardiopulmonary bypass time, cross clamp time or the use of deep hypothermic cardiac
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arrest. (Table 1) There was a slightly higher number of NYHA Class III in phase 2
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compared to matched patients in phase 0, although NYHA Class I, II and IV were similar
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and the ejection fractions were not statistically different between groups.
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Following matching, 19.9% (51/256) had at least one intervention for RBS in phase 0.
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(Table 2) Of matched patients with RBS in Phase 0, 4.7% (12/256) had a re-exploration
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for bleeding, 2.7% (7/256) had an intervention for pericardial effusion, 11.7% (30/256)
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had an intervention for pleural effusion (thoracentesis or chest tube drainage), and 3.9%
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(10/256) had an intervention for pneumothorax. (Table 2) After the universal
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implementation of ATC in phase 2, the percent of matched patients with interventions for
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ATC was reduced by 43% to 11.3% (29/256). (P = 0.0087). This was primarily due to a
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reduction in interventions to treat pleural effusions. The incidences of re-exploration for
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bleeding, interventions for pericardial effusions and interventions for pneumothorax were
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lower in phase 2 than in matched patients in phase 0, however individually the
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differences did not reach statistical significance. Phase 2 patients had a significantly
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reduced incidence of POAF overall compared to matched patients in phase 0. (P =
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0.013) There was not a statistically significant reduction in hospital mortality, cardiac
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arrest, or permanent stroke. Median chest drainage (P = 0.0024) and ventilation hours
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(P = 0.0047) were reduced in phase 2 compared to matched patients in phase 0, but not
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length of stay (P = 0.24). (Table 3)
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The baseline was reassessed for potential temporal trends after the completion of phase
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2. Matched patients in phase 3 and phase 0 remained similar in terms of age, sex, pre
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op anticoagulation, hematocrit, COPD, hypertension, ejection fraction, operative type,
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elective status, reoperative status, cardiopulmonary bypass time, and cross clamp time.
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(Table 4) There was a slightly higher number of NYHA Class II and III in phase 3
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compared to matched patients in phase 0, although NYHA Class I and IV were not
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statistically different. The mean ejection fraction was slightly lower in phase 3 (58.3%
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+/-13.1 vs 54.9% +/-13.8, P = 0.01). Operative characteristics were similar, except a
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higher number of patients having DCA in phase 0. (6 (3%) vs 0 (0%), P 0.041). The
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RBS rate was comparable in phase 3 (17.6%) vs. matched baseline phase 0 patients
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(17.6%) (P = 1), as was the POAF rate (31.5% in phase 3 vs. 23.9% in matched phase
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0, P = 0.079). (Table 5) A significant reduction in ventilator time persisted from matched
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phase 0 to matched phase 3 patients. (Table 6)
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Discussion:
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Chest tubes can obstruct, limiting evacuation capacity. In a survey of cardiothoracic
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surgeons and cardiac surgery nurses, 100% had observed chest tube clogging and a
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large majority recognized adverse events related to this complication.(2) In a
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prospective observational study, 36% of chest tubes were documented as occluded 10
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after heart surgery within the first 24 hours.(3) Current methods to prevent chest tube
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clogging, such as chest tube stripping and milking have not been shown to be effective,
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and may be harmful.(8, 9)
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We set out to define our incidence of RBS and determine if a protocol to better maintain
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chest tube patency improves outcomes. We focused specifically on interventions for
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retained blood rather than more broadly on diagnosis of retained blood since the need
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for an intervention suggests a more clinically relevant subset than those that simply
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have a diagnosis of an effusion, for example, but treated medically. Our incidence of
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RBS interventions was 20%. Our analysis suggested that the need for interventions for
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RBS was not predictable by preoperative by the type of procedure performed (CABG,
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Valve, CABG/Valve, other), the urgency status or if the case was a reoperation.
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Accordingly, we chose to develop a universal use protocol with the goal of preventing
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RBS by proactively maintaining chest tube patency in all patients, rather than only
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selected high-risk patients.
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Next we set out to determine if by implementing our universal protocol to keep chest
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tubes free of blood clot in the early hours after heart surgery we could reduce RBS. We
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chose to utilize the PleuraFlow Active Clearance Technology System, a device that
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allows nurses to periodically clean the entire length of the chest tube by breaking down
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clots with loop on a guide wire (4). ATC had been shown to be highly effective reducing
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RBS in pre clinical studies.(10, 11) ATC had been assessed in a limited evaluation to
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be implementable in the clinical setting.(12) The clinical efficacy for ATC in reducing
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postoperative complications has never been tested.
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Using this methodology, we found a substantial reduction in RBS in patients treated with
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the ATC. In addition, we noted a significant reduction in POAF with the implementation
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of a universal ATC protocol. (Figure 1) The reduction in RBS was primarily from a
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reduction in pleural and pericardial effusions. We postulate that the mechanism of
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reduced effusions may in part be related the well described cross talk between
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coagulation and inflammation that may ensue once blood is retained in the pericardial or
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pleural spaces (13, 14). Studies have documented that early pleural and pericardial
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effusions are primarily exudative, bloody and inflammatory (15-18). Blood retained in
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the pericardial or pleural spaces, even if in insufficient volume to cause mechanical
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compressive compromise, undergoes inflammatory changes over the subsequent days
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that can result in exudative fluid production that manifests as pericardial or pleural
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effusions (19, 20). As blood clots, thrombin is generated, which amplifies an acute and
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chronic inflammatory responses within the pericardial and pleural spaces (21). In
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response, inflammatory mediators are locally produced which are known to activate
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tissue permeability factors by mesothelial cells, such as vascular endothelial growth
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factor (VEGF) (22). VEGF is the primary mediator of exudative permeability leading to
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effusions (22). VEGF levels have been shown to rise and stay elevated in effusions
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after cardiac surgery.(23) This causes inflammatory, exudative fluid to weep into the
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pleural and pericardial spaces, resulting in bloody effusions. One mechanism to explain
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the reduction in clinically significant effusions with ATC is that by more completely
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evacuating the shed blood around the heart and lungs, less blood is retained, and
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subsequently less inflammation and VEGF is generated locally. The result may be less
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inflammation of the mesothelial cells lining the pleura and pericardium to drive exudative
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fluid production that results in effusions.
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This same mechanism might also contribute to the reduction in POAF. Although there
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may be many factors that contribute to the development of POAF, RBS in the
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pericardium has been linked with playing a significant role, perhaps by inducing surface
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cardiac irritation and inflammation (24, 25). Studies have linked both chest tube
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clogging and retained pericardial blood with POAF (3, 26). Others have demonstrated
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that shunting blood through pericardial windows to divert the blood to the pleural spaces
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reduces POAF (26, 27). One advantage that ATC may have over pericardiotomy is that
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the blood is not simply shunted to the pleural spaces (where it can contribute to pleural
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effusions) and there may be less potential for complications such as herniation and long
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term adhesions of the lung to the heart through the widely opened posterior pericardium.
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There was not an appreciable reduction in the need for re-explorations for hemorrhage
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with the use of ATC in phase 2 versus phase 0. Re-explorations for bleeding are
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primarily for surgical bleeding, but in some cases no bleeding sources are noted and
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only clot in and around the mediastinum is found (6). One would not expect a reduction
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in re-explorations to manage surgical bleeding sources by simply improving drainage. In
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theory, however, improved drainage may allow a patient with a medical source of
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bleeding to stay stable in the ICU longer, perhaps avoiding tamponade and thus the
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trigger to return to the operating room for re-exploration while the coagulation defect is
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corrected. Similarly, the addition of a single ATC in the mediastinum did not reduce the
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need for interventions for pneumothorax in this study.
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As part of this continuous quality initiative, we examined for temporal trends over the
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course of the study. In phase 3 there was a rebound of RBS and POAF after cessation
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of the ATC protocol in phase 2 suggesting a return of the primary endpoint. There was
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also a trend toward reduced ventilator time (hours) and length of stay over the course of
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this study through the end of phase 3 suggesting other temporal trends not accounted
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for by ATC. This may be attributed to other quality improvement efforts in the ICU
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during the study intervals and thus not likely associated with the use of ATC. There also
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appeared to be a reduction in the mean total blood loss in phase 2 vs 0. Individual chest
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tube outputs, however, were not quantified and thus the clinical significance of this
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finding is unclear in this study. One can postulate that perhaps by having an open and
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functioning chest tube on suction while the patient is bleeding, there is less opportunity
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for blood to pool around the heart and mediastinum and that this may lead to less
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pericardial thrombolytic effect therefore less micro-vascular bleeding. Further studies to
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better understand the impact of ATC on chest tube outputs are indicated.
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We believe this study is important for a number of reasons. Chest tubes are used on
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every cardiac surgery case, with a known failure rate due to clogging that is much higher
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than previously expected (2, 3). The finding that nearly 20% of patients require
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interventions for RBS suggests this problem is a clinically significant and potentially a
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modifiable problem. The current approaches to preventing chest tube clogging, such as
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milking and stripping, have been proven ineffective and may be potentially harmful (8,
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9). Make shift approaches such as opening tubes (after clogging occurs) and suctioning
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them or using a balloon catheter to remove clot raise safety concerns (28, 29). Given
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the lack of suitable methods to routinely prevent chest tube clogging in the ICU, this
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study is a step towards studying alternatives.
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Although the results are encouraging, important limitations need to be considered. This
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was not a randomized prospective trial. As such, we did not control for all variables
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during the study period. There may have been changes in ICU protocols and other
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variables that limit the ability to draw conclusions about ventilator times especially in this
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study. An additional limitation was that this was a retrospective study of prospectively
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collected database elements, and such databases may contain incomplete information
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or errors in the manual extraction of data. Furthermore, there were data elements that
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were not collected this study, particularly with regard to the numbers and locations of
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conventional chest tubes, reasons and findings at reexploration for bleeding, cytology of
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effusions, and details regarding coagulopathy. These are important considerations in
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further studies. Although the study size was large enough to compare baseline (phase
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0) to phases 2 and 3, the sizes of phase 2 and 3 were too small for robust statistical
325
comparison between these groups. Additionally, we used a proxy to estimate RBS
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(need for interventions), but did not use direct imaging modalities to quantify the amount
327
of retained blood, which will be considered for further studies. Finally, this analysis did
328
not include the economic data comparing the cost of the technology vs the cost savings
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from complication avoidance. This is a critical variable in the assessment of any new
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modality and will be considered in subsequent studies.
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Conclusions: We observed a signification reduction in the composite endpoint of RBS
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as well as interventions for pleural effusions and POAF.
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associated with implementing a formalized ATC protocol universally in consecutive
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patients undergoing heart surgery. Our findings underscore the importance of
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maintaining chest tube patency in the early recovery after heart surgery and suggest the
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need for further studies to devise optimal protocols to optimize.
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These reductions were
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Acknowledgements: The authors are thankful for the help and efforts of all nursing
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staff in the operating room and the intensive care physicians and nurses in the
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Cardiothoracic Intensive Care Units for their assistance developing and adopting the
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ATC protocol for this study. The authors also thank Corey Powel, Ph.D, for statistical
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consultation and Josef Thalmann.
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Presented at the Foundation for the Advancement of Cardiothoracic Surgical Care
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(FACTS-Care) Cardiovascular-Thoracic (CVT) Critical Care meeting on October 10,
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2014 in Washington, DC.
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Abbreviations and Acronyms:
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RBS = Retained Blood Syndrome
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POAF = Post Operative Atrial Fibrillation
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CABG = Coronary Artery Bypass Surgery
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ATC= Active Tube Clearance
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CPB = Cardiopulmonary Bypass
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DCA = Deep Hypothermic Circulatory Arrest
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IMC = Intermediate Care Unit
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Location Phase Operating Room Chest Closure (OR) Transfer to ICU
0- 8 hours 8 to 24 hours > 24 hours
Cycles/Hour 4 per hour
Every 15’
Every 15’ Every 30’
4 per hour 2 per hour
Every hour
1 per hour
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Figure 1: Outcomes for matched patients in phase 0 vs phase 2
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Early Bleeding Slowed Bleeding Serosanguinous drainage
Frequency
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Intensive Care Unit (ICU)
Timing 1 x at time of closure 1 x at transfer to bed Continue use if delay
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Table 1: Matched Comparison of Demographic Characteristics for Phase 2 vs Phase 0 McNemar or paired T-test P-value
68.6 (10.6) 197 (77%) 65 (25%) 37 (14%) 15 (6%) 173 (68%) 40.0 (4.7) 37 (14%) 234 (91%) 24 (9%) 62 (24%) 148 (58%) 21 (8%) 58.0 (12.8)
68.1 (10.9) 199 (78%) 62 (24%) 27 (11%) 19 (7%) 174 (68%) 39.7 (5.5%) 42 (16%) 241 (94%) 17 (7%) 38 (15%) 179 (70%) 22 (9%) 57.1 (12.4)
0.059 0.68 0.37 0.22 0.56 1 0.59 0.6 0.31 0.28 0.01 0.0088 1 0.44
148 (58%) 65 (25%) 20 (8%) 23 (9%) 178 (70%) 23 (9%) 98.1 (49.0) 57 (31.5) 3 (1%)
0.89 0.55 1 0.37 0.45 0.48 0.57 0.87 0.45
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Phase 2 (n = 256)
150 (59%) 60 (23%) 20 (8%) 26 (10%) 181 71%) 21 (8%) 96.3 (56.3) 57.5 (32.2) 6 (2%)
394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409
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Age (years) Male Pre-op anticoagulation Plavix Coumadin Aspirin Pre-op Hct (n=255) COPD Hypertension NYHA Class I NYHA Class II NYHA Class III NYHA Class IV EF (n = 255) Operative Type CABG Valve CABG+Valve Other Status (elective) Re-operation (Yes) CPB (min) (n =251) Cross Clamp (min) (n = 251) DCA
Phase 0 (n = 256)
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Hct = Hematocrit COPD = Chronic Obstructive Pulmonary Disease EF = Ejection Fraction CABG = Coronary Artery Bypass Surgery CPB = Cardiopulmonary Bypass DCA = Deep Hypothermic Arrest
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Table 2: Propensity Matched Postoperative Outcomes in Phase 2 vs Phase 0 P Value
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Phase 2 (n = 256) 29 (11.3%) 9 (3.5%) 17 (6.6%) 1 (0.4%) 7 (2.7%) 52 (20%) 4 (2%) 12 (5%)
43% 26% 44% 85% 44% 33% 0% 0%
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RBS (composite) Re-exploration Pleural Intervention Pericardial Intervention Pneumothorax POAF Stroke Mortality
0.0087 0.65 0.061 0.077 0.63 0.013 1 1
Table 3: Differences between Phase 2 and Phase 0 for matched pairs 25th % -350.0
LOS (days) n = 256
-115
-4
Vent (hrs) N = 255
-1,590
-9
75th % 137.5
Maximum 2,250
P-value 0.0024
0
4
65
0.24
4.50
1,141
0.0047
-2
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Median -50.0
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CT Drainage (ml) n = 231
430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450
Phase 0 (n = 256) 51 (19.9%) 12 (4.7%) 30 (11.7%) 7 (2.7%) 10 (3.9%) 78 (30%) 4 (2%) 2 (5%)
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410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429
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Table 4: Matched Comparison of Demographic Characteristics for Phase 3 vs Phase 0 McNemar or paired T-test P-value
67.2 (11.7) 158 (71%)
67.9 (11.0) 160 (72%)
0.41 0.91
36 (16%) 18 (8%) 136 (61%) 38.2 (5.3) 36 (16%) 199 (90%) 18 (8%) 64 (29%) 120 (54%) 20 (8%) 58.3 (13.1%)
18 (8%) 14 (6%) 145 (65%) 38.2 (5.9%) 28 (13%) 203 (91%) 10 (5%) 20 (9%) 173 (78%) 22 (9%) 54.9 (13.8)
0.012 0.58 0.37 0.23 0.34 0.6 0.17
S0022-5223(15)01970-4
DOI:
10.1016/j.jtcvs.2015.10.015
Reference:
YMTC 10050
To appear in:
The Journal of Thoracic and Cardiovascular Surgery
Received Date: 20 November 2014 Revised Date:
1 October 2015
Accepted Date: 10 October 2015
Please cite this article as: Sirch J, Ledwon M, Pu¨ski T, Boyle E, Pfeiffer S, Fischlein T, Active Clearance of Chest Drainage Catheters Reduces Retained Blood, The Journal of Thoracic and Cardiovascular Surgery (2015), doi: 10.1016/j.jtcvs.2015.10.015. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Active Clearance of Chest Drainage Catheters Reduces Retained Blood
2 Authors: J Sirch, MD.1, M Ledwon, MD1, T Püski, MD1, EM Boyle, MD.2, S Pfeiffer,
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MD1, T Fischlein, MD1
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5 Institutions:
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Paracelsus Medical University, Nuremberg, Germany,
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Dept. of Cardiac Surgery, Kllinikum Nürnberg,
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St. Charles Medical Center, Bend, Oregon, United States
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Funding Source: Funded in part by a grant from ClearFlow, Inc.
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Disclosures: Dr. Boyle is a founding shareholder and board member of ClearFlow, Inc.
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and is paid a consulting fee for his work. Drs. Sirch, Ledwon, Puski, Pfeiffer and
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Fischlein have no potential conflicts of interest.
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Address for Reprints:
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Prof. Dr. Theodor Fischlein
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Dept. of Cardiac Surgery, Klinikum Nürnberg
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Paracelsus Medical University
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Breslauer Str. 201
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90471 Nuremberg, Germany
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Abstract:
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Objectives: Chest tubes are utilized to clear blood from around the heart and lungs
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after heart surgery, but they can obstruct with clot, leading to retained blood syndrome
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(RBS). This study sought to examine the frequency of RBS and associated morbidity,
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and to determine the impact of a preventative active chest tube clearance protocol on
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these outcomes. Methods: A multidisciplinary team developed a simple protocol to
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institute active tube clearance (ATC) to preventatively clear chest tubes of clot in the first
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24 hours after heart surgery. An extensive educational in-service was performed before
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universal implementation (phase 1). We retrospectively compared data collected
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prospectively from 1,849 patients before (phase 0) with data from 256 patients collected
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prospectively after universal implementation (phase 2), and then used propensity
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matching for outcomes assessment. Results: In propensity-matched patients, 19.9%
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of patients had interventions for RBS (phase 0). After the implementation of ATC
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(phase 2), the percent of patients with interventions for RBS was reduced to 11.3%,
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representing a 43% reduction in RBS (P = 0.0087). These patients had a 33% reduced
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incidence of postoperative atrial fibrillation (POAF) from 30% (78/256) in phase 0 to 20%
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(53/256) in phase 2. (P = 0.013). Conclusions: ATC is associated with a reduced
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need for interventions for RBS and POAF. Our findings underscore the importance of
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maintaining chest tube patency in the early hours after cardiac surgery.
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Central Message: Active tube clearance reduces interventions for RBS and POAF,
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underscoring the importance of maintaining chest tube patency after cardiac surgery.
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Perspective Statement: All patients require chest tubes to drain shed blood after heart
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surgery, yet clogging of chest tubes is common. We studied a protocol to maintain
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chest tube patency with active tube clearance and demonstrated an associated
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reduction in retained blood syndrome and postoperative atrial fibrillation. Our findings
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underscore the importance of maintaining chest tube patency in outcomes after cardiac
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surgery.
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Introduction
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Postoperative bleeding is common to some degree in nearly all patients in the early
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hours after heart surgery (1). To obtain adequate evacuation, chest tubes are utilized to
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drain shed blood and prevent retained collections around the heart and lungs (2). Chest
60
tubes, however, can obstruct with clot, impairing their evacuation capacity. Recently, a
61
prospective observational study quantified that 36% of chest tubes obstruct after heart
62
surgery, often in the internal portion inside the patients where the obstruction goes
63
unnoticed to the care givers (3). We hypothesized that chest tube obstruction might
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contribute to retained blood syndrome (RBS) after cardiac surgery. To study this
65
hypothesis we initiated a continuous quality improvement process to assess the
66
incidence of RBS, then develop and implement a universal protocol utilizing active tube
67
clearance (ATC) to periodically clear the internal lumen of chest tubes.
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Materials and Methods
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Data was collected from our institutional cardiac surgery database. Structured data
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elements are routinely prospectively collected and available for retrospective analysis.
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Operative variables included the type of surgery (CABG, Valve, CABG+Valve, Other)
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and re operative status. Procedures in the “Other” category included isolated ascending
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and aortic arch procedures. The primary outcomes measured were interventions for
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RBS, a composite outcome consisting of any of the following interventions: take back
75
for re-exploration for hemorrhage; pericardial interventions (pericardial window or
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pericardiocentesis); and pleural interventions for hemothorax, pneumothorax or
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effusions. Patients that had interventions for more than one component of RBS were
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only counted once. Patients that had the diagnosis of pleural or pericardial effusion or
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hemothorax or hemopneumothorax but did not undergo a specific invasive intervention
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were excluded. Secondary outcomes included postoperative atrial fibrillation (POAF),
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cardiac arrest, permanent stroke, postoperative hospital length of stay (LOS), and the
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total chest tube drainage volume (mL). All patients were fitted with at least one 28 Fr
83
chest tube in the anterior mediastinum. We do not routinely open the pleura to harvest
84
the mammary artery, but when it happens, the surgeons place a pleural 28 Fr chest
85
tube. Rarely, a retro cardiac 28 Fr chest tube is placed. Blake or channel type drains
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were not used in any patient in this study. All patients were treated with tranexamic
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acid. An institutional trigger to transfuse for a hemoglobin of 7.5 g/dL to 8 g/dL was
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adhered to in all phases of this study.
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From January 1, 2011 to June 11, 2014, 3,226 adult cardiac surgical procedures were
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performed at the Nuremberg Cardiovascular Center. Patients were divided into 4
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phases for analysis.
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Phase 0: Pre ATC Protocol: From January 1, 2011 to December 31, 2012, 1,849
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cardiac surgery procedures were performed. No patients in this group were treated with
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ATC. These patients were divided into those with any one of the RBS interventions
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versus those without to establish a baseline for measurement of clinical outcomes.
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Phase 1: Limited Implementation for ATC Protocol Development, Training and
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Compliance Verification. A multidisciplinary team developed a simple protocol to
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institute active clearance technology (ATC) to clear chest tubes in the first 24 hours after
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heart surgery. The PleuraFlow Active Clearance Technology System (ClearFlow, Inc.,
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Anaheim, CA) is a chest tube clearance apparatus with a mechanism to actively keep 5
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the entire inner diameter of the chest tube clear of obstructing blood clot or fibrinous
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debris (4). Care providers periodically advance a clearance apparatus back and forth
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within the catheter by actuating the shuttle, which couples via a magnet to the clearance
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member to maintain sterility while the tube is cleared.
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Multidisciplinary team meetings were held for protocol development with cardiac surgical
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staff, residents and fellows, anesthesiologists and critical care physicians and cardiac
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ICU nurses. The objective was to develop a simple protocol to implement ATC that
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could be integrated into the workflow. In prior studies, the most common sites for
113
bleeding identified at reoperation were the mediastinum, sternum, internal thoracic
114
artery bed, and coronary anastomosis sites (5, 6). For sake of simplicity, it was decided
115
to use a single ATC unit (28 Fr) in an anterior mediastinal position. After 24 hours, the
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chest tube with ATC was removed, or the chest tube was left in place and the ATC
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pulled back and its use was discontinued. Most were removed by the 2nd postop day.
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Surgeons were allowed to place additional conventional chest tubes at their discretion,
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however in a majority only a single mediastinal ATC was utilized. The protocol
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developed allows for more frequent use early on, when chest tube outputs tend to be
121
higher, and less so in subsequent hours, as well as on an as needed basis (Appendix
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A.) (7) The nurses were free to strip and milk the conventional chest tubes as they felt
123
were needed. An extensive educational in-service was performed before universal
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implementation for training of all nurses and physician in the ICU with compliance
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verification. This protocol was rolled out in phase 1 starting on January 1, 2013 through
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November 30, 2013 during which time there were 914 heart surgery cases.
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128 Phase 2: Universal Implementation of ATC Protocol. We implemented phase 2 with
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ATC universally in all consecutive patients from December 1, 2013 to March 16, 2014.
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Phase 3: Post Protocol Re-Measurement. In this phase we stopped the universal
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implementation of ATC and returned to using all conventional chest tubes (without ATC)
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and repeated measurement of outcomes (March 18, 2014 to June 11, 2014).
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This study was an investigator-initiated study that was supported in part by a research
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grant from ClearFlow, Inc. The study site investigators had full access to the data, the
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ability to analyze them independently from the sponsor, and sole authority to make the
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final decision regarding publication. ClearFlow, Inc., played no role in the collection of
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data and had no right to approve or disapprove publication of the finished manuscript.
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Measurement and Analysis
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Our institutional Ethics Committee and an independent Ethics Committee Review Board
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approved this study. We compared results from 1,849 patients before (phase 0) with
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256 patients after universal implementation (phase 2), and then the results of stopping
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the protocol in 222 patients (phase 3), to determine the impact of ATC on outcomes.
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258 patients were approached for consent in phase 2, and 256 agreed to provide
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consent to participate. A complete set of data was available from all patients except for
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chest tube drainage (n = 231) and ventilator hours (n = 255) in phase 2.
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Comparisons of categorical variables used a Chi-squared or Fisher's exact test, as 7
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appropriate, while comparisons of continuous variables used Welch's test if the variable
153
was symmetrically distributed and Wilcoxon's rank sum test if the variable had a skewed
154
distribution. Propensity scoring was utilized to balance the distributions of measured
155
potentially confounding baseline covariates using the matchit function from the R
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package MatchIt with 1:1 nearest neighbor matching based on age, gender, operative
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status (urgent or elective), redo status, procedure (CABG, Valve, CABG + Valve, or
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other), and use of anticoagulants. The analysis compared matched pairs using
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McNemar's test for categorical variables, paired T-tests for symmetrically distributed
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variables, and Wilcoxon's signed rank test for skewed continuous variables.
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161 Results:
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The overall incidence of RBS at baseline (Phase 0) was 19.5% (360/1,849). The
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incidence of RBS in phase 0 was not markedly different for surgery types: 18%
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(182/1,011) for CABG only patients, 19% (83/436) for valve surgery patients, 21%
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(55/260) for combined valve/CABG patients, 29% (41/142), 25% (36/142) for patients
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with other types of surgery. Patients in phase 0 and phase 2 were comparable, except
168
an increased number of patients with CABG/Valve in phase 0 and slightly fewer NYHA
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Class II and III patients in phase 2. (E Table 1). In phase 2 there was a 42% reduction
170
in the primary endpoint of RBS from 19.5% (360/1,849) to 11.3% (29/256). (E-table 2)
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To account for potential differences between phase 0 and phase 2, a propensity score
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model was used to match a sub cohort of patients in phase 0 that were well balanced for
174
comorbidities and operative variables with patients in phase 2. After propensity
175
matching, 256 of 1,849 patients in phase 0 were selected for comparison with 256 8
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patients in phase 2. Propensity score matching between phase 0 and 2 found
177
agreement for 97.7% for gender, 97.3% for operative status, 80.9% for procedures,
178
98.1% for the use of anticoagulants, 99.2% for redo status, and 95.7% for an age
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difference less than 5 years. After matching, there were no differences between Phase
180
0 and Phase 2 with respect to age, sex, pre op anticoagulation, hematocrit, COPD,
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hypertension, ejection fraction, operative type, elective status, reoperative status,
182
cardiopulmonary bypass time, cross clamp time or the use of deep hypothermic cardiac
183
arrest. (Table 1) There was a slightly higher number of NYHA Class III in phase 2
184
compared to matched patients in phase 0, although NYHA Class I, II and IV were similar
185
and the ejection fractions were not statistically different between groups.
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Following matching, 19.9% (51/256) had at least one intervention for RBS in phase 0.
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(Table 2) Of matched patients with RBS in Phase 0, 4.7% (12/256) had a re-exploration
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for bleeding, 2.7% (7/256) had an intervention for pericardial effusion, 11.7% (30/256)
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had an intervention for pleural effusion (thoracentesis or chest tube drainage), and 3.9%
191
(10/256) had an intervention for pneumothorax. (Table 2) After the universal
192
implementation of ATC in phase 2, the percent of matched patients with interventions for
193
ATC was reduced by 43% to 11.3% (29/256). (P = 0.0087). This was primarily due to a
194
reduction in interventions to treat pleural effusions. The incidences of re-exploration for
195
bleeding, interventions for pericardial effusions and interventions for pneumothorax were
196
lower in phase 2 than in matched patients in phase 0, however individually the
197
differences did not reach statistical significance. Phase 2 patients had a significantly
198
reduced incidence of POAF overall compared to matched patients in phase 0. (P =
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0.013) There was not a statistically significant reduction in hospital mortality, cardiac
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arrest, or permanent stroke. Median chest drainage (P = 0.0024) and ventilation hours
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(P = 0.0047) were reduced in phase 2 compared to matched patients in phase 0, but not
202
length of stay (P = 0.24). (Table 3)
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The baseline was reassessed for potential temporal trends after the completion of phase
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2. Matched patients in phase 3 and phase 0 remained similar in terms of age, sex, pre
206
op anticoagulation, hematocrit, COPD, hypertension, ejection fraction, operative type,
207
elective status, reoperative status, cardiopulmonary bypass time, and cross clamp time.
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(Table 4) There was a slightly higher number of NYHA Class II and III in phase 3
209
compared to matched patients in phase 0, although NYHA Class I and IV were not
210
statistically different. The mean ejection fraction was slightly lower in phase 3 (58.3%
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+/-13.1 vs 54.9% +/-13.8, P = 0.01). Operative characteristics were similar, except a
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higher number of patients having DCA in phase 0. (6 (3%) vs 0 (0%), P 0.041). The
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RBS rate was comparable in phase 3 (17.6%) vs. matched baseline phase 0 patients
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(17.6%) (P = 1), as was the POAF rate (31.5% in phase 3 vs. 23.9% in matched phase
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0, P = 0.079). (Table 5) A significant reduction in ventilator time persisted from matched
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phase 0 to matched phase 3 patients. (Table 6)
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Discussion:
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Chest tubes can obstruct, limiting evacuation capacity. In a survey of cardiothoracic
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surgeons and cardiac surgery nurses, 100% had observed chest tube clogging and a
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large majority recognized adverse events related to this complication.(2) In a
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prospective observational study, 36% of chest tubes were documented as occluded 10
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after heart surgery within the first 24 hours.(3) Current methods to prevent chest tube
224
clogging, such as chest tube stripping and milking have not been shown to be effective,
225
and may be harmful.(8, 9)
226
We set out to define our incidence of RBS and determine if a protocol to better maintain
227
chest tube patency improves outcomes. We focused specifically on interventions for
228
retained blood rather than more broadly on diagnosis of retained blood since the need
229
for an intervention suggests a more clinically relevant subset than those that simply
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have a diagnosis of an effusion, for example, but treated medically. Our incidence of
231
RBS interventions was 20%. Our analysis suggested that the need for interventions for
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RBS was not predictable by preoperative by the type of procedure performed (CABG,
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Valve, CABG/Valve, other), the urgency status or if the case was a reoperation.
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Accordingly, we chose to develop a universal use protocol with the goal of preventing
235
RBS by proactively maintaining chest tube patency in all patients, rather than only
236
selected high-risk patients.
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Next we set out to determine if by implementing our universal protocol to keep chest
238
tubes free of blood clot in the early hours after heart surgery we could reduce RBS. We
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chose to utilize the PleuraFlow Active Clearance Technology System, a device that
240
allows nurses to periodically clean the entire length of the chest tube by breaking down
241
clots with loop on a guide wire (4). ATC had been shown to be highly effective reducing
242
RBS in pre clinical studies.(10, 11) ATC had been assessed in a limited evaluation to
243
be implementable in the clinical setting.(12) The clinical efficacy for ATC in reducing
244
postoperative complications has never been tested.
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Using this methodology, we found a substantial reduction in RBS in patients treated with
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the ATC. In addition, we noted a significant reduction in POAF with the implementation
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of a universal ATC protocol. (Figure 1) The reduction in RBS was primarily from a
248
reduction in pleural and pericardial effusions. We postulate that the mechanism of
249
reduced effusions may in part be related the well described cross talk between
250
coagulation and inflammation that may ensue once blood is retained in the pericardial or
251
pleural spaces (13, 14). Studies have documented that early pleural and pericardial
252
effusions are primarily exudative, bloody and inflammatory (15-18). Blood retained in
253
the pericardial or pleural spaces, even if in insufficient volume to cause mechanical
254
compressive compromise, undergoes inflammatory changes over the subsequent days
255
that can result in exudative fluid production that manifests as pericardial or pleural
256
effusions (19, 20). As blood clots, thrombin is generated, which amplifies an acute and
257
chronic inflammatory responses within the pericardial and pleural spaces (21). In
258
response, inflammatory mediators are locally produced which are known to activate
259
tissue permeability factors by mesothelial cells, such as vascular endothelial growth
260
factor (VEGF) (22). VEGF is the primary mediator of exudative permeability leading to
261
effusions (22). VEGF levels have been shown to rise and stay elevated in effusions
262
after cardiac surgery.(23) This causes inflammatory, exudative fluid to weep into the
263
pleural and pericardial spaces, resulting in bloody effusions. One mechanism to explain
264
the reduction in clinically significant effusions with ATC is that by more completely
265
evacuating the shed blood around the heart and lungs, less blood is retained, and
266
subsequently less inflammation and VEGF is generated locally. The result may be less
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inflammation of the mesothelial cells lining the pleura and pericardium to drive exudative
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fluid production that results in effusions.
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This same mechanism might also contribute to the reduction in POAF. Although there
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may be many factors that contribute to the development of POAF, RBS in the
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pericardium has been linked with playing a significant role, perhaps by inducing surface
272
cardiac irritation and inflammation (24, 25). Studies have linked both chest tube
273
clogging and retained pericardial blood with POAF (3, 26). Others have demonstrated
274
that shunting blood through pericardial windows to divert the blood to the pleural spaces
275
reduces POAF (26, 27). One advantage that ATC may have over pericardiotomy is that
276
the blood is not simply shunted to the pleural spaces (where it can contribute to pleural
277
effusions) and there may be less potential for complications such as herniation and long
278
term adhesions of the lung to the heart through the widely opened posterior pericardium.
279
There was not an appreciable reduction in the need for re-explorations for hemorrhage
280
with the use of ATC in phase 2 versus phase 0. Re-explorations for bleeding are
281
primarily for surgical bleeding, but in some cases no bleeding sources are noted and
282
only clot in and around the mediastinum is found (6). One would not expect a reduction
283
in re-explorations to manage surgical bleeding sources by simply improving drainage. In
284
theory, however, improved drainage may allow a patient with a medical source of
285
bleeding to stay stable in the ICU longer, perhaps avoiding tamponade and thus the
286
trigger to return to the operating room for re-exploration while the coagulation defect is
287
corrected. Similarly, the addition of a single ATC in the mediastinum did not reduce the
288
need for interventions for pneumothorax in this study.
289
As part of this continuous quality initiative, we examined for temporal trends over the
290
course of the study. In phase 3 there was a rebound of RBS and POAF after cessation
291
of the ATC protocol in phase 2 suggesting a return of the primary endpoint. There was
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also a trend toward reduced ventilator time (hours) and length of stay over the course of
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this study through the end of phase 3 suggesting other temporal trends not accounted
294
for by ATC. This may be attributed to other quality improvement efforts in the ICU
295
during the study intervals and thus not likely associated with the use of ATC. There also
296
appeared to be a reduction in the mean total blood loss in phase 2 vs 0. Individual chest
297
tube outputs, however, were not quantified and thus the clinical significance of this
298
finding is unclear in this study. One can postulate that perhaps by having an open and
299
functioning chest tube on suction while the patient is bleeding, there is less opportunity
300
for blood to pool around the heart and mediastinum and that this may lead to less
301
pericardial thrombolytic effect therefore less micro-vascular bleeding. Further studies to
302
better understand the impact of ATC on chest tube outputs are indicated.
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We believe this study is important for a number of reasons. Chest tubes are used on
304
every cardiac surgery case, with a known failure rate due to clogging that is much higher
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than previously expected (2, 3). The finding that nearly 20% of patients require
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interventions for RBS suggests this problem is a clinically significant and potentially a
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modifiable problem. The current approaches to preventing chest tube clogging, such as
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milking and stripping, have been proven ineffective and may be potentially harmful (8,
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9). Make shift approaches such as opening tubes (after clogging occurs) and suctioning
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them or using a balloon catheter to remove clot raise safety concerns (28, 29). Given
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the lack of suitable methods to routinely prevent chest tube clogging in the ICU, this
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study is a step towards studying alternatives.
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Although the results are encouraging, important limitations need to be considered. This
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was not a randomized prospective trial. As such, we did not control for all variables
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during the study period. There may have been changes in ICU protocols and other
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variables that limit the ability to draw conclusions about ventilator times especially in this
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study. An additional limitation was that this was a retrospective study of prospectively
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collected database elements, and such databases may contain incomplete information
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or errors in the manual extraction of data. Furthermore, there were data elements that
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were not collected this study, particularly with regard to the numbers and locations of
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conventional chest tubes, reasons and findings at reexploration for bleeding, cytology of
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effusions, and details regarding coagulopathy. These are important considerations in
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further studies. Although the study size was large enough to compare baseline (phase
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0) to phases 2 and 3, the sizes of phase 2 and 3 were too small for robust statistical
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comparison between these groups. Additionally, we used a proxy to estimate RBS
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(need for interventions), but did not use direct imaging modalities to quantify the amount
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of retained blood, which will be considered for further studies. Finally, this analysis did
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not include the economic data comparing the cost of the technology vs the cost savings
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from complication avoidance. This is a critical variable in the assessment of any new
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modality and will be considered in subsequent studies.
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Conclusions: We observed a signification reduction in the composite endpoint of RBS
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as well as interventions for pleural effusions and POAF.
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associated with implementing a formalized ATC protocol universally in consecutive
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patients undergoing heart surgery. Our findings underscore the importance of
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maintaining chest tube patency in the early recovery after heart surgery and suggest the
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need for further studies to devise optimal protocols to optimize.
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These reductions were
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Acknowledgements: The authors are thankful for the help and efforts of all nursing
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staff in the operating room and the intensive care physicians and nurses in the
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Cardiothoracic Intensive Care Units for their assistance developing and adopting the
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ATC protocol for this study. The authors also thank Corey Powel, Ph.D, for statistical
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consultation and Josef Thalmann.
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Presented at the Foundation for the Advancement of Cardiothoracic Surgical Care
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(FACTS-Care) Cardiovascular-Thoracic (CVT) Critical Care meeting on October 10,
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2014 in Washington, DC.
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Abbreviations and Acronyms:
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RBS = Retained Blood Syndrome
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POAF = Post Operative Atrial Fibrillation
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CABG = Coronary Artery Bypass Surgery
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ATC= Active Tube Clearance
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CPB = Cardiopulmonary Bypass
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DCA = Deep Hypothermic Circulatory Arrest
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IMC = Intermediate Care Unit
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Location Phase Operating Room Chest Closure (OR) Transfer to ICU
0- 8 hours 8 to 24 hours > 24 hours
Cycles/Hour 4 per hour
Every 15’
Every 15’ Every 30’
4 per hour 2 per hour
Every hour
1 per hour
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Figure 1: Outcomes for matched patients in phase 0 vs phase 2
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Early Bleeding Slowed Bleeding Serosanguinous drainage
Frequency
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Intensive Care Unit (ICU)
Timing 1 x at time of closure 1 x at transfer to bed Continue use if delay
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Appendix A: ATC Actuation Schedule
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Table 1: Matched Comparison of Demographic Characteristics for Phase 2 vs Phase 0 McNemar or paired T-test P-value
68.6 (10.6) 197 (77%) 65 (25%) 37 (14%) 15 (6%) 173 (68%) 40.0 (4.7) 37 (14%) 234 (91%) 24 (9%) 62 (24%) 148 (58%) 21 (8%) 58.0 (12.8)
68.1 (10.9) 199 (78%) 62 (24%) 27 (11%) 19 (7%) 174 (68%) 39.7 (5.5%) 42 (16%) 241 (94%) 17 (7%) 38 (15%) 179 (70%) 22 (9%) 57.1 (12.4)
0.059 0.68 0.37 0.22 0.56 1 0.59 0.6 0.31 0.28 0.01 0.0088 1 0.44
148 (58%) 65 (25%) 20 (8%) 23 (9%) 178 (70%) 23 (9%) 98.1 (49.0) 57 (31.5) 3 (1%)
0.89 0.55 1 0.37 0.45 0.48 0.57 0.87 0.45
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Phase 2 (n = 256)
150 (59%) 60 (23%) 20 (8%) 26 (10%) 181 71%) 21 (8%) 96.3 (56.3) 57.5 (32.2) 6 (2%)
394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409
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Age (years) Male Pre-op anticoagulation Plavix Coumadin Aspirin Pre-op Hct (n=255) COPD Hypertension NYHA Class I NYHA Class II NYHA Class III NYHA Class IV EF (n = 255) Operative Type CABG Valve CABG+Valve Other Status (elective) Re-operation (Yes) CPB (min) (n =251) Cross Clamp (min) (n = 251) DCA
Phase 0 (n = 256)
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Hct = Hematocrit COPD = Chronic Obstructive Pulmonary Disease EF = Ejection Fraction CABG = Coronary Artery Bypass Surgery CPB = Cardiopulmonary Bypass DCA = Deep Hypothermic Arrest
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Table 2: Propensity Matched Postoperative Outcomes in Phase 2 vs Phase 0 P Value
RI PT
% Reduction
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RBS = Retained Blood Syndrome POAF = Post Operative Atrial Fibrillation
Phase 2 (n = 256) 29 (11.3%) 9 (3.5%) 17 (6.6%) 1 (0.4%) 7 (2.7%) 52 (20%) 4 (2%) 12 (5%)
43% 26% 44% 85% 44% 33% 0% 0%
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RBS (composite) Re-exploration Pleural Intervention Pericardial Intervention Pneumothorax POAF Stroke Mortality
0.0087 0.65 0.061 0.077 0.63 0.013 1 1
Table 3: Differences between Phase 2 and Phase 0 for matched pairs 25th % -350.0
LOS (days) n = 256
-115
-4
Vent (hrs) N = 255
-1,590
-9
75th % 137.5
Maximum 2,250
P-value 0.0024
0
4
65
0.24
4.50
1,141
0.0047
-2
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Median -50.0
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CT Drainage (ml) n = 231
430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450
Phase 0 (n = 256) 51 (19.9%) 12 (4.7%) 30 (11.7%) 7 (2.7%) 10 (3.9%) 78 (30%) 4 (2%) 2 (5%)
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Table 4: Matched Comparison of Demographic Characteristics for Phase 3 vs Phase 0 McNemar or paired T-test P-value
67.2 (11.7) 158 (71%)
67.9 (11.0) 160 (72%)
0.41 0.91
36 (16%) 18 (8%) 136 (61%) 38.2 (5.3) 36 (16%) 199 (90%) 18 (8%) 64 (29%) 120 (54%) 20 (8%) 58.3 (13.1%)
18 (8%) 14 (6%) 145 (65%) 38.2 (5.9%) 28 (13%) 203 (91%) 10 (5%) 20 (9%) 173 (78%) 22 (9%) 54.9 (13.8)
0.012 0.58 0.37 0.23 0.34 0.6 0.17
