Online Letters to the Editor
Hsu et al (1) further wondered whether our failure to find an association between classic ventilator bundle components (head of bed elevation, routine oral care with chlorhexidine, venous thrombosis prophylaxis, and stress ulcer prophylaxis) and VAC or IVAC preludes the possibility that these interventions might still prevent ventilator-associated pneumonias (VAPs). We did not have sufficient numbers of pneumonias to specifically assess the relationship between ventilator bundle adherence rates and pneumonia. Nonetheless, if the classic ventilator bundle is effective in preventing pneumonias, we might have expected to see associations between bundle components and IVAC risk since about two thirds of IVACs typically qualify as possible or probable pneumonias (7). Furthermore, current ventilator bundles are not without controversy (8, 9). Multiple before-after and time-series analyses have associated bundle implementations with lower VAP rates, but very few have shown parallel improvements in more concrete outcomes, such as duration of mechanical ventilation, ICU length of stay, or mortality (10). In addition, ventilator bundles have never been evaluated in a randomized controlled trial or in a study where the VAP assessors were blinded to whether or not patients were receiving bundle interventions. This raises the possibility that some of the observed reductions in VAP rates attributed to bundles may be due to the Hawthorne effect, observer biases, and circularity between selected interventions (e.g., oral care with chlorhexidine) and surveillance definitions (e.g., positive endotracheal aspirates) (11). Ultimately, the introduction of ventilator-associated event (VAE) definitions offers an opportunity to reexamine existing ventilator bundles to determine whether they contain what we currently recognize to be the most effective strategies to improve outcomes for ventilated patients. VAE surveillance helps affirm that pulmonary edema, atelectasis, and ARDS are common and morbid complications of critical care in addition to pneumonia. Ventilator bundles ought to be revised to better reflect current best practices to prevent these events. Supported, in part, by the Centers for Disease Control and Prevention (CDC). Dr. Lewis is employed by the UCSF Medical Center. Mr. Murphy has disclosed other relationship (he is data analyst for an ongoing trial in which participating hospitals are receiving product contribution from Sage and Molnlycke). Dr. Klompas received support for travel from the Infectious Disease Society of America, the Society for Healthcare Epidemiology of America, the American College of Chest Physicians, the American Society for Microbiology, the Infectious Disease Association of California, and the Texas Hospital Association, and he received honoraria for lectures on ventilator-associated event/ ventilator-associated pneumonia surveillance from Premier Healthcare Alliance and received grant support from the CDC. His institution received grant support from the CDC and the Agency for Healthcare Research Quality. Sarah C. Lewis, MD, Division of Infectious Disease, University of California San Francisco, San Francisco,
Critical Care Medicine
CA; Michael V. Murphy, BA, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA; Michael Klompas, MD, MPH, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA, and Department of Medicine, Brigham and Women’s Hospital, Boston, MA
REFERENCES
1. Hsu H-Y, Kung S-C, Chang H-C, et al: Need More In-Depth Analysis of Ventilator-Associated Events? Crit Care Med 2014; 42:e726 2. Lewis SC, Li L, Murphy MV, et al; CDC Prevention Epicenters: Risk factors for ventilator-associated events: A case-control multivariable analysis. Crit Care Med 2014; 42:1839–1848 3. Klompas M, Khan Y, Kleinman K, et al; CDC Prevention Epicenters Program: Multicenter evaluation of a novel surveillance paradigm for complications of mechanical ventilation. PLoS One 2011; 6:e18062 4. Hayashi Y, Morisawa K, Klompas M, et al: Toward improved surveillance: The impact of ventilator-associated complications on length of stay and antibiotic use in patients in intensive care units. Clin Infect Dis 2013; 56:471–477 5. Klein Klouwenberg PM, van Mourik MS, Ong DS, et al; MARS Consortium: Electronic implementation of a novel surveillance paradigm for ventilator-associated events. Feasibility and validation. Am J Respir Crit Care Med 2014; 189:947–955 6. Boyer AF, Schoenberg N, Babcock H, et al: A prospective evaluation of ventilator-associated conditions and infection-related ventilatorassociated conditions. Chest 2014 May 22. [Epub ahead of print] 7. Klompas M, Kleinman K, Murphy MV: Descriptive epidemiology and attributable morbidity of ventilator-associated events. Infect Control Hosp Epidemiol 2014; 35:502–510 8. Kalil AC, Wiener-Kronish JP: Is the evidence for benefits from ventilator-associated pneumonia bundles reliable enough for implementation in a general hospital? Crit Care Med 2012; 40:348–350 9. Zilberberg MD, Shorr AF, Kollef MH: Implementing quality improvements in the intensive care unit: Ventilator bundle as an example. Crit Care Med 2009; 37:305–309 10. Klompas M: Ventilator-associated pneumonia: Is zero possible? Clin Infect Dis 2010; 51:1123–1126 11. Klompas M: The paradox of ventilator-associated pneumonia prevention measures. Crit Care 2009; 13:315 DOI: 10.1097/CCM.0000000000000599
There Is a Pressing Need for an EvidenceBased Algorithm for Mechanical Circulatory Support in Cardiogenic Shock To the Editor:
W
ith great interest, I read the article by Petroni et al (1). These authors nicely described the beneficial effects of intra-aortic balloon pump (IABP) support on global hemodynamics, whereas microcirculation was not improved, in patients with cardiogenic shock assisted by venoarterial extracorporeal membrane oxygenation (VA-ECMO). These effects were partly demonstrated before in patients with cardiogenic shock assisted by IABP alone (2). Registries like these provide insight in hemodynamics and are hypothesisgenerating. However, for now, we urgently need an algorithm of how patients with cardiogenic shock are best mechanically assisted, in case of failing pharmacologic support. Therefore, it will be necessary to answer the following questions. www.ccmjournal.org
e727
Online Letters to the Editor
First, after publication of the Intraaortic Balloon Pump in Cardiogenic Shock II (IABP-SHOCK II) trial data (3), is there still a role for the IABP in cardiogenic shock or should use of the IABP be replaced by percutaneous left ventricular assist devices (pLVADs)? After all, pLVADs are able to provide better hemodynamic support (4), however, without final proof of benefit on clinical endpoints (5). Second, in which patients, and when, should we escalate to VA-ECMO support? And finally, should VA-ECMO support be combined with either IABP or pLVAD? I strongly encourage all investigators involved in cardiogenic shock to join our forces and test these questions in adequately powered multicenter randomized controlled trials. The author has disclosed that he does not have any potential conflicts of interest. Corstiaan A. den Uil, MD, PhD Department of Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands
REFERENCES
1. Petroni T, Harrois A, Amour J, et al: Intra-Aortic Balloon Pump Effects on Macrocirculation and Microcirculation in Cardiogenic Shock Patients Supported by Venoarterial Extracorporeal Membrane Oxygenation. Crit Care Med 2014 May 7 [Epub ahead of print] 2. den Uil CA, Lagrand WK, van der Ent M, et al: The effects of intraaortic balloon pump support on macrocirculation and tissue microcirculation in patients with cardiogenic shock. Cardiology 2009; 114:42–46 3. Thiele H, Zeymer U, Neumann FJ, et al; Intraaortic Balloon Pump in cardiogenic shock II (IABP-SHOCK II) trial investigators: Intra-aortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock (IABP-SHOCK II): Final 12 month results of a randomised, open-label trial. Lancet 2013; 382:1638–1645 4. Engström AE, Cocchieri R, Driessen AH, et al: The Impella 2.5 and 5.0 devices for ST-elevation myocardial infarction patients presenting with severe and profound cardiogenic shock: The Academic Medical Center intensive care unit experience. Crit Care Med 2011; 39:2072–2079 5. Cheng JM, den Uil CA, Hoeks SE, et al: Percutaneous left ventricular assist devices vs. intra-aortic balloon pump counterpulsation for treatment of cardiogenic shock: A meta-analysis of controlled trials. Eur Heart J 2009; 30:2102–2108 DOI: 10.1097/CCM.0000000000000535
The author replies:
W
e appreciate the interest of den Uil (1) in our work (2) in a recent issue of Critical Care Medicine. We concur with den Uil (1) that an algorithm of how patients with cardiogenic shock should be best mechanically assisted in case of failing pharmacologic support is lacking. As of now, only one nonrandomized, retrospective, observational study (3) compared patients with ST-segment elevation myocardial infarction-related “profound cardiogenic shock” undergoing percutaneous coronary intervention with (n = 46) and without (n = 25) extracorporeal membrane oxygenation (ECMO) support. Those receiving ECMO had a significantly lower 30-day mortality than those who did not receive ECMO (39.1% vs 72%; p = 0.008). Interpretation of this data is limited by the fact that each cohort was enrolled over a different
e728
www.ccmjournal.org
timeframe (1993–2002 for the non-ECMO cohort vs 2002– 2009 for the ECMO cohort), potentially leading to discrepancies in both medical and interventional management between groups, especially given that coronary stents were unavailable at the study center prior to 1998. The Intraaortic Balloon Pump in Cardiogenic Shock II (IABPSHOCK II) trial data showed that mortality remained more than 40% for patients diagnosed with cardiogenic shock at the acute phase of myocardial infarction and that inserting an IABP was not associated with a better outcome (4). We do agree that a prospective randomized controlled trial is now urgently needed to determine the true benefit, if any, of venoarterial ECMO in myocardial infarction-associated cardiogenic shock (5). Dr. Combes consulted for Maquet and received other support from Maquet (cosponsor of the ECMO to rescue Lung Injury in severe Acute Respiratory Distress Syndrome trial). Alain Combes, MD, PhD, Service de Réanimation Médicale, iCAN, Institute of Cardiometabolism and Nutrition, Hôpital Pitié–Salpêtrière, Assistance Publique–Hôpitaux de Paris, Université Pierre et Marie Curie, Paris, France
REFERENCES
1. den Uil CA: There Is a Pressing Need for an Evidence-Based Algorithm for Mechanical Circulatory Support in Cardiogenic Shock. Crit Care Med 2014; 42:e727–e728 2. Petroni T, Harrois A, Amour J, et al: Intra-aortic balloon pump effects on macrocirculation and microcirculation in cardiogenic shock patients supported by venoarterial extracorporeal membrane oxygenation. Crit Care Med 2014; 42:2075–2082 3. Sheu JJ, Tsai TH, Lee FY, et al: Early extracorporeal membrane oxygenator-assisted primary percutaneous coronary intervention improved 30-day clinical outcomes in patients with ST-segment elevation myocardial infarction complicated with profound cardiogenic shock. Crit Care Med 2010; 38:1810–1817 4. Thiele H, Zeymer U, Neumann FJ, et al; IABP-SHOCK II Trial Investigators: Intraaortic balloon support for myocardial infarction with cardiogenic shock. N Engl J Med 2012; 367:1287–1296 5. Abrams D, Combes A, Brodie D: Extracorporeal membrane oxygenation in cardiopulmonary disease in adults. J Am Coll Cardiol 2014; 63:2769–2778 DOI: 10.1097/CCM.0000000000000629
Does Prophylactic Intra-Aortic Balloon Pumping Really Fail to Improve Perioperative Outcomes in Patients With Poor Left Ventricular Function? To the Editor:
I
n a recent issue of Critical Care Medicine, we read with great interest the article by Ranucci et al (1), and we congratulate the authors for their elegant prospective randomized controlled trial aimed at providing a definite answer to the still very controversially discussed question, whether a preoperatively inserted intra-aortic balloon pump (IABP) improves outcomes in patients with poor ventricular function undergoing bypass surgery. Although a plethora of literature is available, it is worth discussing this issue because much of the existing evidence on the efficacy derives from studies dating back to the 1970s (2). November 2014 • Volume 42 • Number 11
Hsu et al (1) further wondered whether our failure to find an association between classic ventilator bundle components (head of bed elevation, routine oral care with chlorhexidine, venous thrombosis prophylaxis, and stress ulcer prophylaxis) and VAC or IVAC preludes the possibility that these interventions might still prevent ventilator-associated pneumonias (VAPs). We did not have sufficient numbers of pneumonias to specifically assess the relationship between ventilator bundle adherence rates and pneumonia. Nonetheless, if the classic ventilator bundle is effective in preventing pneumonias, we might have expected to see associations between bundle components and IVAC risk since about two thirds of IVACs typically qualify as possible or probable pneumonias (7). Furthermore, current ventilator bundles are not without controversy (8, 9). Multiple before-after and time-series analyses have associated bundle implementations with lower VAP rates, but very few have shown parallel improvements in more concrete outcomes, such as duration of mechanical ventilation, ICU length of stay, or mortality (10). In addition, ventilator bundles have never been evaluated in a randomized controlled trial or in a study where the VAP assessors were blinded to whether or not patients were receiving bundle interventions. This raises the possibility that some of the observed reductions in VAP rates attributed to bundles may be due to the Hawthorne effect, observer biases, and circularity between selected interventions (e.g., oral care with chlorhexidine) and surveillance definitions (e.g., positive endotracheal aspirates) (11). Ultimately, the introduction of ventilator-associated event (VAE) definitions offers an opportunity to reexamine existing ventilator bundles to determine whether they contain what we currently recognize to be the most effective strategies to improve outcomes for ventilated patients. VAE surveillance helps affirm that pulmonary edema, atelectasis, and ARDS are common and morbid complications of critical care in addition to pneumonia. Ventilator bundles ought to be revised to better reflect current best practices to prevent these events. Supported, in part, by the Centers for Disease Control and Prevention (CDC). Dr. Lewis is employed by the UCSF Medical Center. Mr. Murphy has disclosed other relationship (he is data analyst for an ongoing trial in which participating hospitals are receiving product contribution from Sage and Molnlycke). Dr. Klompas received support for travel from the Infectious Disease Society of America, the Society for Healthcare Epidemiology of America, the American College of Chest Physicians, the American Society for Microbiology, the Infectious Disease Association of California, and the Texas Hospital Association, and he received honoraria for lectures on ventilator-associated event/ ventilator-associated pneumonia surveillance from Premier Healthcare Alliance and received grant support from the CDC. His institution received grant support from the CDC and the Agency for Healthcare Research Quality. Sarah C. Lewis, MD, Division of Infectious Disease, University of California San Francisco, San Francisco,
Critical Care Medicine
CA; Michael V. Murphy, BA, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA; Michael Klompas, MD, MPH, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA, and Department of Medicine, Brigham and Women’s Hospital, Boston, MA
REFERENCES
1. Hsu H-Y, Kung S-C, Chang H-C, et al: Need More In-Depth Analysis of Ventilator-Associated Events? Crit Care Med 2014; 42:e726 2. Lewis SC, Li L, Murphy MV, et al; CDC Prevention Epicenters: Risk factors for ventilator-associated events: A case-control multivariable analysis. Crit Care Med 2014; 42:1839–1848 3. Klompas M, Khan Y, Kleinman K, et al; CDC Prevention Epicenters Program: Multicenter evaluation of a novel surveillance paradigm for complications of mechanical ventilation. PLoS One 2011; 6:e18062 4. Hayashi Y, Morisawa K, Klompas M, et al: Toward improved surveillance: The impact of ventilator-associated complications on length of stay and antibiotic use in patients in intensive care units. Clin Infect Dis 2013; 56:471–477 5. Klein Klouwenberg PM, van Mourik MS, Ong DS, et al; MARS Consortium: Electronic implementation of a novel surveillance paradigm for ventilator-associated events. Feasibility and validation. Am J Respir Crit Care Med 2014; 189:947–955 6. Boyer AF, Schoenberg N, Babcock H, et al: A prospective evaluation of ventilator-associated conditions and infection-related ventilatorassociated conditions. Chest 2014 May 22. [Epub ahead of print] 7. Klompas M, Kleinman K, Murphy MV: Descriptive epidemiology and attributable morbidity of ventilator-associated events. Infect Control Hosp Epidemiol 2014; 35:502–510 8. Kalil AC, Wiener-Kronish JP: Is the evidence for benefits from ventilator-associated pneumonia bundles reliable enough for implementation in a general hospital? Crit Care Med 2012; 40:348–350 9. Zilberberg MD, Shorr AF, Kollef MH: Implementing quality improvements in the intensive care unit: Ventilator bundle as an example. Crit Care Med 2009; 37:305–309 10. Klompas M: Ventilator-associated pneumonia: Is zero possible? Clin Infect Dis 2010; 51:1123–1126 11. Klompas M: The paradox of ventilator-associated pneumonia prevention measures. Crit Care 2009; 13:315 DOI: 10.1097/CCM.0000000000000599
There Is a Pressing Need for an EvidenceBased Algorithm for Mechanical Circulatory Support in Cardiogenic Shock To the Editor:
W
ith great interest, I read the article by Petroni et al (1). These authors nicely described the beneficial effects of intra-aortic balloon pump (IABP) support on global hemodynamics, whereas microcirculation was not improved, in patients with cardiogenic shock assisted by venoarterial extracorporeal membrane oxygenation (VA-ECMO). These effects were partly demonstrated before in patients with cardiogenic shock assisted by IABP alone (2). Registries like these provide insight in hemodynamics and are hypothesisgenerating. However, for now, we urgently need an algorithm of how patients with cardiogenic shock are best mechanically assisted, in case of failing pharmacologic support. Therefore, it will be necessary to answer the following questions. www.ccmjournal.org
e727
Online Letters to the Editor
First, after publication of the Intraaortic Balloon Pump in Cardiogenic Shock II (IABP-SHOCK II) trial data (3), is there still a role for the IABP in cardiogenic shock or should use of the IABP be replaced by percutaneous left ventricular assist devices (pLVADs)? After all, pLVADs are able to provide better hemodynamic support (4), however, without final proof of benefit on clinical endpoints (5). Second, in which patients, and when, should we escalate to VA-ECMO support? And finally, should VA-ECMO support be combined with either IABP or pLVAD? I strongly encourage all investigators involved in cardiogenic shock to join our forces and test these questions in adequately powered multicenter randomized controlled trials. The author has disclosed that he does not have any potential conflicts of interest. Corstiaan A. den Uil, MD, PhD Department of Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, The Netherlands
REFERENCES
1. Petroni T, Harrois A, Amour J, et al: Intra-Aortic Balloon Pump Effects on Macrocirculation and Microcirculation in Cardiogenic Shock Patients Supported by Venoarterial Extracorporeal Membrane Oxygenation. Crit Care Med 2014 May 7 [Epub ahead of print] 2. den Uil CA, Lagrand WK, van der Ent M, et al: The effects of intraaortic balloon pump support on macrocirculation and tissue microcirculation in patients with cardiogenic shock. Cardiology 2009; 114:42–46 3. Thiele H, Zeymer U, Neumann FJ, et al; Intraaortic Balloon Pump in cardiogenic shock II (IABP-SHOCK II) trial investigators: Intra-aortic balloon counterpulsation in acute myocardial infarction complicated by cardiogenic shock (IABP-SHOCK II): Final 12 month results of a randomised, open-label trial. Lancet 2013; 382:1638–1645 4. Engström AE, Cocchieri R, Driessen AH, et al: The Impella 2.5 and 5.0 devices for ST-elevation myocardial infarction patients presenting with severe and profound cardiogenic shock: The Academic Medical Center intensive care unit experience. Crit Care Med 2011; 39:2072–2079 5. Cheng JM, den Uil CA, Hoeks SE, et al: Percutaneous left ventricular assist devices vs. intra-aortic balloon pump counterpulsation for treatment of cardiogenic shock: A meta-analysis of controlled trials. Eur Heart J 2009; 30:2102–2108 DOI: 10.1097/CCM.0000000000000535
The author replies:
W
e appreciate the interest of den Uil (1) in our work (2) in a recent issue of Critical Care Medicine. We concur with den Uil (1) that an algorithm of how patients with cardiogenic shock should be best mechanically assisted in case of failing pharmacologic support is lacking. As of now, only one nonrandomized, retrospective, observational study (3) compared patients with ST-segment elevation myocardial infarction-related “profound cardiogenic shock” undergoing percutaneous coronary intervention with (n = 46) and without (n = 25) extracorporeal membrane oxygenation (ECMO) support. Those receiving ECMO had a significantly lower 30-day mortality than those who did not receive ECMO (39.1% vs 72%; p = 0.008). Interpretation of this data is limited by the fact that each cohort was enrolled over a different
e728
www.ccmjournal.org
timeframe (1993–2002 for the non-ECMO cohort vs 2002– 2009 for the ECMO cohort), potentially leading to discrepancies in both medical and interventional management between groups, especially given that coronary stents were unavailable at the study center prior to 1998. The Intraaortic Balloon Pump in Cardiogenic Shock II (IABPSHOCK II) trial data showed that mortality remained more than 40% for patients diagnosed with cardiogenic shock at the acute phase of myocardial infarction and that inserting an IABP was not associated with a better outcome (4). We do agree that a prospective randomized controlled trial is now urgently needed to determine the true benefit, if any, of venoarterial ECMO in myocardial infarction-associated cardiogenic shock (5). Dr. Combes consulted for Maquet and received other support from Maquet (cosponsor of the ECMO to rescue Lung Injury in severe Acute Respiratory Distress Syndrome trial). Alain Combes, MD, PhD, Service de Réanimation Médicale, iCAN, Institute of Cardiometabolism and Nutrition, Hôpital Pitié–Salpêtrière, Assistance Publique–Hôpitaux de Paris, Université Pierre et Marie Curie, Paris, France
REFERENCES
1. den Uil CA: There Is a Pressing Need for an Evidence-Based Algorithm for Mechanical Circulatory Support in Cardiogenic Shock. Crit Care Med 2014; 42:e727–e728 2. Petroni T, Harrois A, Amour J, et al: Intra-aortic balloon pump effects on macrocirculation and microcirculation in cardiogenic shock patients supported by venoarterial extracorporeal membrane oxygenation. Crit Care Med 2014; 42:2075–2082 3. Sheu JJ, Tsai TH, Lee FY, et al: Early extracorporeal membrane oxygenator-assisted primary percutaneous coronary intervention improved 30-day clinical outcomes in patients with ST-segment elevation myocardial infarction complicated with profound cardiogenic shock. Crit Care Med 2010; 38:1810–1817 4. Thiele H, Zeymer U, Neumann FJ, et al; IABP-SHOCK II Trial Investigators: Intraaortic balloon support for myocardial infarction with cardiogenic shock. N Engl J Med 2012; 367:1287–1296 5. Abrams D, Combes A, Brodie D: Extracorporeal membrane oxygenation in cardiopulmonary disease in adults. J Am Coll Cardiol 2014; 63:2769–2778 DOI: 10.1097/CCM.0000000000000629
Does Prophylactic Intra-Aortic Balloon Pumping Really Fail to Improve Perioperative Outcomes in Patients With Poor Left Ventricular Function? To the Editor:
I
n a recent issue of Critical Care Medicine, we read with great interest the article by Ranucci et al (1), and we congratulate the authors for their elegant prospective randomized controlled trial aimed at providing a definite answer to the still very controversially discussed question, whether a preoperatively inserted intra-aortic balloon pump (IABP) improves outcomes in patients with poor ventricular function undergoing bypass surgery. Although a plethora of literature is available, it is worth discussing this issue because much of the existing evidence on the efficacy derives from studies dating back to the 1970s (2). November 2014 • Volume 42 • Number 11
