© 2013 Wiley Periodicals, Inc.
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ORIGINAL ARTICLE _____________________________________________________________
Adult Respiratory Distress Syndrome Following Cardiac Surgery A. Kogan, M.D.,*,z S. Preisman, M.D.,y,z S. Levin, M.A.,*,z E. Raanani, M.D.,*,z and L. Sternik, M.D.*,z *Department of Cardiac Surgery, Sheba Medical Center, Tel Hashomer, Israel; yDepartment of Anesthesiology, Sheba Medical Center, Tel Hashomer, Israel; and zSackler School of Medicine, Tel Aviv University, Tel Aviv, Israel ABSTRACT Background: Severe lung injury with the development of acute respiratory distress syndrome (ARDS) is a serious complication of cardiac surgery. The aim of this study was to determine the incidence, risk factors, and mortality of ARDS following cardiac surgery. Methods: We retrospectively analyze data in the period between January 2005 and March 2013. Results: Of 6069 patients who underwent cardiac surgery during the study period, 37 patients developed ARDS during the postoperative period. The incidence of ARDS was 0.61%, with a mortality of 40.5% (15 patients). Multivariate regression analysis identified previous cardiac surgery, complex cardiac surgery, and more than three transfusions with packed red blood cells (PRBC) were independent predictors for developing ARDS. Conclusions: ARDS remains a serious, but very rare complication associated with significant mortality. In our study, previous cardiac surgery, complex cardiac surgery, and more than three transfusions of PRBC were independent predictors for the development of ARDS. doi: 10.1111/jocs.12264 (J Card Surg 2014;29:41–46) Acute respiratory distress syndrome (ARDS) is a clinical syndrome characterized by diffuse endothelial injury, noncardiogenic pulmonary edema, and severe hypoxia. Development of this syndrome is associated with a morbidity of 36% to 44% with little change over the past decades.1 The mortality is especially high following cardiac surgery.2 ‘‘Previous studies that investigated the development and risk factors for ARDS cover the period from 1980 to 2000.3–9 However, during the last decade, the profile of patients undergoing cardiac surgery has changed. An increasing number of patients are currently referred for complex procedures, the number of isolated coronary artery bypass surgeries has declined10,11 and previous investigations about ARDS related to cardiac surgery may be less relevant to the contemporary population. In this study, we investigate current prevalence, perioperative risk factors, and outcomes in patients who developed ARDS after cardiac surgery. The second aim of the study was to perform a systematic review of the literature to determine the incidence, mortality, and risk factors for developing ARDS after cardiac surgery.
Conflict of interest: The authors acknowledge no conflict of interest in the submission. Address for correspondence: Alexander Kogan, M.D., Department of Cardiac Surgery, Sheba Medical Center, Tel Hashomer 52621, Israel. Fax: þ972-3-5302410; e-mail: [email protected], [email protected]
PATIENTS AND METHODS This was a retrospective, observational study that included prospectively collected data from consecutive patients who had undergone cardiac surgery at a large tertiary university hospital. Data from collection forms were entered into a computerized department database that was approved by the Ethics Committee of our Medical Center as an information source. Using nonidentifiable patient data from our department’s database, we evaluated the following variables: sex, age, presence of congestive heart failure (NYHA III–IV), peripheral vascular disease, chronic obstructive pulmonary disease, diabetes mellitus, presence of preoperative renal failure, and left ventricular function. Peri- and postoperative variables included priority of surgery (elective, urgent, or emergent), type of surgery, duration of cross-clamping and bypass, number of transfusions with PRBC, reoperation for bleeding, postoperative renal failure, pneumonia, sepsis, and presence of low cardiac output (LCO) syndrome. LCO syndrome was defined as a cardiac index less than 2 L/m2 measured by thermodilutional technique (SwanGanz pulmonary artery catheter) or by arterial pressurebased cardiac output technique (FloTrac/Vigileo) (both Edwards Lifesciences, Irvine, CA, USA). In addition, the presence of ARSD was one of the postoperative variables introduced into the database. Complex surgery was defined as concomitant CABG and valve surgery or more valve surgery.
42
KOGAN, ET AL. ARDS AFTER CARDIAC SURGERY
J CARD SURG 2014;29:41–46
Outcome measures of the study were the incidence of ARDS, in-hospital mortality after ARDS, as well as preoperative and perioperative predisposing factors for this complication. ARDS was defined according to the AmericanEuropean Consensus Conference on ARDS.12 The presence of the LCO syndrome or pulmonary capillary wedge pressure (PCWP) more than 18 mmHg at the time of hypoxia were exclusion criteria for diagnosis of ARDS. Chest X-rays (CXR) were assessed on a daily basis by an experienced cardiothoracic surgeon and/or intensivist. Arterial blood gas data were used for assessment of hypoxia. The management of ARDS included standard supportive therapy. First and foremost was the treatment of the underlying cause, if possible (e.g., sepsis). In addition to lung protective lowtidal volume ventilation, fluid restriction, adequate nutrition, corticosteroids according to the Meduri protocol,13 and inhalation of nitric oxide. In the three cases of refractory hypoxemia, we used prone positioning.14 We did not use ECMO for the treatment of ARDS. The study population comprised 6069 patients who had undergone cardiac surgery over an 8.25-year period, from January 1, 2005 to March 31, 2012 (see Table 1). Throughout this period, the same surgical and anesthesiology team performed all the procedures, and there were no major changes in hospital policy or surgical or anesthesiology techniques.
Database management and statistical analysis Upon discharge, patient data were checked and corrected and all patient data were entered into a database, which was programmed to exclude entry of any out-of-scale values. An experienced research coordinator (S.L.) analyzed each patient’s file using a database questionnaire, and continued to monitor all patient data. Descriptive statistics were used to summarize the data, and numerical data were expressed as means standard deviation (SD).The comparison between the survivors and nonsurvivors was performed by Student’s t-test. Risk factors for the development of ARDS such as described in previous studies such as postoperative LCO, current smoking, LVEF < 40%, NYHA class III–IV, hypertension, combined cardiac procedures, emergency operation, advanced COPD (FEV1/FVC < 40%), emergency CABG, previous cardiac surgery, shock, multiple transfusions, and complex cardiac surgery were introduced into the univariate analysis.3–9 In addition, we evaluated the following risk factors: peripheral vascular disease, diabetes mellitus, preoperative renal failure, postoperative pneumonia, sepsis, and standard and logistic EuroSCORE. Multivariate stepwise forward logistic regression analysis was then performed with statistically significant univariate predictors in order to find independent predictors of developing ARDS. P-values
TABLE 1 Perioperative Characteristics Number of patients Sex (male, %) Age, years (range, median) Systemic hypertension (n, %) Peripheral vascular disease (n, %) COPD (n, %) Current smoking (n, %) Diabetes (n, %) Preoperative renal failure (n, %) Congestive heart failure (NYHA III–IV) (n, %) Cardiogenic shock (n, %) LVEF
41
ORIGINAL ARTICLE _____________________________________________________________
Adult Respiratory Distress Syndrome Following Cardiac Surgery A. Kogan, M.D.,*,z S. Preisman, M.D.,y,z S. Levin, M.A.,*,z E. Raanani, M.D.,*,z and L. Sternik, M.D.*,z *Department of Cardiac Surgery, Sheba Medical Center, Tel Hashomer, Israel; yDepartment of Anesthesiology, Sheba Medical Center, Tel Hashomer, Israel; and zSackler School of Medicine, Tel Aviv University, Tel Aviv, Israel ABSTRACT Background: Severe lung injury with the development of acute respiratory distress syndrome (ARDS) is a serious complication of cardiac surgery. The aim of this study was to determine the incidence, risk factors, and mortality of ARDS following cardiac surgery. Methods: We retrospectively analyze data in the period between January 2005 and March 2013. Results: Of 6069 patients who underwent cardiac surgery during the study period, 37 patients developed ARDS during the postoperative period. The incidence of ARDS was 0.61%, with a mortality of 40.5% (15 patients). Multivariate regression analysis identified previous cardiac surgery, complex cardiac surgery, and more than three transfusions with packed red blood cells (PRBC) were independent predictors for developing ARDS. Conclusions: ARDS remains a serious, but very rare complication associated with significant mortality. In our study, previous cardiac surgery, complex cardiac surgery, and more than three transfusions of PRBC were independent predictors for the development of ARDS. doi: 10.1111/jocs.12264 (J Card Surg 2014;29:41–46) Acute respiratory distress syndrome (ARDS) is a clinical syndrome characterized by diffuse endothelial injury, noncardiogenic pulmonary edema, and severe hypoxia. Development of this syndrome is associated with a morbidity of 36% to 44% with little change over the past decades.1 The mortality is especially high following cardiac surgery.2 ‘‘Previous studies that investigated the development and risk factors for ARDS cover the period from 1980 to 2000.3–9 However, during the last decade, the profile of patients undergoing cardiac surgery has changed. An increasing number of patients are currently referred for complex procedures, the number of isolated coronary artery bypass surgeries has declined10,11 and previous investigations about ARDS related to cardiac surgery may be less relevant to the contemporary population. In this study, we investigate current prevalence, perioperative risk factors, and outcomes in patients who developed ARDS after cardiac surgery. The second aim of the study was to perform a systematic review of the literature to determine the incidence, mortality, and risk factors for developing ARDS after cardiac surgery.
Conflict of interest: The authors acknowledge no conflict of interest in the submission. Address for correspondence: Alexander Kogan, M.D., Department of Cardiac Surgery, Sheba Medical Center, Tel Hashomer 52621, Israel. Fax: þ972-3-5302410; e-mail: [email protected], [email protected]
PATIENTS AND METHODS This was a retrospective, observational study that included prospectively collected data from consecutive patients who had undergone cardiac surgery at a large tertiary university hospital. Data from collection forms were entered into a computerized department database that was approved by the Ethics Committee of our Medical Center as an information source. Using nonidentifiable patient data from our department’s database, we evaluated the following variables: sex, age, presence of congestive heart failure (NYHA III–IV), peripheral vascular disease, chronic obstructive pulmonary disease, diabetes mellitus, presence of preoperative renal failure, and left ventricular function. Peri- and postoperative variables included priority of surgery (elective, urgent, or emergent), type of surgery, duration of cross-clamping and bypass, number of transfusions with PRBC, reoperation for bleeding, postoperative renal failure, pneumonia, sepsis, and presence of low cardiac output (LCO) syndrome. LCO syndrome was defined as a cardiac index less than 2 L/m2 measured by thermodilutional technique (SwanGanz pulmonary artery catheter) or by arterial pressurebased cardiac output technique (FloTrac/Vigileo) (both Edwards Lifesciences, Irvine, CA, USA). In addition, the presence of ARSD was one of the postoperative variables introduced into the database. Complex surgery was defined as concomitant CABG and valve surgery or more valve surgery.
42
KOGAN, ET AL. ARDS AFTER CARDIAC SURGERY
J CARD SURG 2014;29:41–46
Outcome measures of the study were the incidence of ARDS, in-hospital mortality after ARDS, as well as preoperative and perioperative predisposing factors for this complication. ARDS was defined according to the AmericanEuropean Consensus Conference on ARDS.12 The presence of the LCO syndrome or pulmonary capillary wedge pressure (PCWP) more than 18 mmHg at the time of hypoxia were exclusion criteria for diagnosis of ARDS. Chest X-rays (CXR) were assessed on a daily basis by an experienced cardiothoracic surgeon and/or intensivist. Arterial blood gas data were used for assessment of hypoxia. The management of ARDS included standard supportive therapy. First and foremost was the treatment of the underlying cause, if possible (e.g., sepsis). In addition to lung protective lowtidal volume ventilation, fluid restriction, adequate nutrition, corticosteroids according to the Meduri protocol,13 and inhalation of nitric oxide. In the three cases of refractory hypoxemia, we used prone positioning.14 We did not use ECMO for the treatment of ARDS. The study population comprised 6069 patients who had undergone cardiac surgery over an 8.25-year period, from January 1, 2005 to March 31, 2012 (see Table 1). Throughout this period, the same surgical and anesthesiology team performed all the procedures, and there were no major changes in hospital policy or surgical or anesthesiology techniques.
Database management and statistical analysis Upon discharge, patient data were checked and corrected and all patient data were entered into a database, which was programmed to exclude entry of any out-of-scale values. An experienced research coordinator (S.L.) analyzed each patient’s file using a database questionnaire, and continued to monitor all patient data. Descriptive statistics were used to summarize the data, and numerical data were expressed as means standard deviation (SD).The comparison between the survivors and nonsurvivors was performed by Student’s t-test. Risk factors for the development of ARDS such as described in previous studies such as postoperative LCO, current smoking, LVEF < 40%, NYHA class III–IV, hypertension, combined cardiac procedures, emergency operation, advanced COPD (FEV1/FVC < 40%), emergency CABG, previous cardiac surgery, shock, multiple transfusions, and complex cardiac surgery were introduced into the univariate analysis.3–9 In addition, we evaluated the following risk factors: peripheral vascular disease, diabetes mellitus, preoperative renal failure, postoperative pneumonia, sepsis, and standard and logistic EuroSCORE. Multivariate stepwise forward logistic regression analysis was then performed with statistically significant univariate predictors in order to find independent predictors of developing ARDS. P-values
TABLE 1 Perioperative Characteristics Number of patients Sex (male, %) Age, years (range, median) Systemic hypertension (n, %) Peripheral vascular disease (n, %) COPD (n, %) Current smoking (n, %) Diabetes (n, %) Preoperative renal failure (n, %) Congestive heart failure (NYHA III–IV) (n, %) Cardiogenic shock (n, %) LVEF
