Online Letters to the Editor
cerebral venous gas embolism in the swine would not be complicated by the presence of the carotid rete, the swine may turn out to be a very suitable model for research on this topic. Dr. Weenink’s institution received grant support from Netherlands Department of Defense (grant number 009-07-5041-01). Dr. Hollmann served as a board member for Anesthesia Analgesia Editorial Board; consulted for Echo Pharmaceuticals (Weesp, The Netherlands), Eurocept, and Merck (Whitehouse Station, NJ); received grant support from International Anesthesia Research Society, ZonMW, and Nederlandse Hartstichting; and lectured for Abbott, Merck, and Pfizer. His institution received grant support from Netherlands Department of Defense (grant number 009-07-5041-01). Mr. Vrijdag, Dr. van Lienden, and Dr. de Boo’s institutions received grant support from The Netherlands Department of Defense (grant number 009-07-5041-01). Dr. Stevens lectured for and received support for development of educational presentations from Abbott and AstraZeneca. His institution received grant support from Netherlands Department of Defense (grant number 009-07-5041-01). Drs. van Gulik and van Hulst’s institutions received grant support from Netherlands Department of Defense (grant number 009-07-5041-01). Robert P. Weenink, MD, PhD, Diving Medical Center, Royal Netherlands Navy, Den Helder, The Netherlands, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Markus W. Hollmann, MD, PhD, DEAA, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Xavier C. E. Vrijdag, MSc, Department of Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Krijn P. van Lienden, MD, PhD, Diederick W. De Boo, MD, PhD, Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Markus F. Stevens, MD, PhD, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Thomas M. van Gulik, MD, PhD, Department of Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Robert A. van Hulst, MD, PhD, Diving Medical Center, Royal Netherlands Navy, Den Helder, The Netherlands, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
REFERENCE
1. Bothma PA, Rice NE: Severe Cerebral Arterial Gas Embolism Can Be Fatal; What About Cerebral Venous Gas Embolism?. Crit Care Med 2014; 42:e249–e250 DOI: 10.1097/CCM.0000000000000155
e252
www.ccmjournal.org
Obesity Paradox in Critically Ill Patients To the Editor:
I
n a recent issue of Critical Care Medicine, we have read with interest the article by Pickkers et al (1) on the obesity paradox in critically ill patients. In the last few years, a huge number of studies have been published focusing on this issue, with similar results. In the study, Pickkers et al (1) have excluded cardiac surgery patients, severe burns, and patients less than 18 years old, but recently, we have published results in obesity in patients undergoing cardiac surgery (2), which surprisingly got a mortality curve very similar to this study. It seems, therefore, that the normal weight or light-moderate obesity is protective, and underweight or morbid obesity increases mortality in critically ill patients. Pickkers et al (1) did not include patients with body mass index (BMI) greater than 55 kg/m2, and this could be the reason that no significant mortality was obtained in this group. To our knowledge, there are no severity scales such as Acute Physiology and Chronic Health Evaluation, Simplified Acute Physiology Score, Sequential Organ Failure Assessment, or European System for Cardiac Operative Risk Evaluation that include BMI or weight in its formula, except Parsonnet (3) for patients undergoing cardiac surgery. But given that we find more and more studies focusing to the protective effect on mortality in critically ill patients, maybe if we might see these items included in the score, we would improve its accuracy. The second main aspect that can be drawn is the unknown mechanism that obesity confers. Mehra et al (4) argue several explanations poorly understood, as receptors in adipocyte cells that neutralize the inflammatory cytokines, thereby reducing the systemic adverse effects (4). Following this line, some authors are trying to link inflammatory cytokines, B-type natriuretic peptide, and others measurable markers with obesity and outcomes. But at present, we do not have a study focusing such aspects in critically ill patients or severity scale involving obesity in its formula. But maybe it is a matter of time. The authors have disclosed that they do not have any potential conflicts of interest. Emilio Curiel-Balsera, MD, Juan M. Mora-Ordoñez, PhD, Javier Muñoz-Bono, PhD, Intensive Care Unit, Carlos Haya Hospital, Málaga, Spain
REFERENCES
1. Pickkers P, de Keizer N, Dusseljee J, et al: Body Mass Index Is Associated With Hospital Mortality in Critically Ill Patients: An Observational Cohort Study. Crit Care Med 2013; 41:1878–1883 2. Curiel-Balsera E, Muñoz-Bono J, Rivera-Fernández R, et al; en representación de los investigadores del proyecto ARIAM de cirugía cardiaca de adultos de Andalucía: [Consequences of obesity in outcomes after cardiac surgery. Analysis of ARIAM registry]. Med Clin (Barc) 2013; 141:100–105 3. Parsonnet V, Dean D, Bernstein AD: A method of uniform stratification of risk for evaluating the results of surgery in acquired adult heart disease. Circulation 1989; 79:I3–12 4. Mehra MR, Uber PA, Park MH, et al: Obesity and suppressed B-type natriuretic peptide levels in heart failure. J Am Coll Cardiol 2004; 43:1590–1595 DOI: 10.1097/CCM.0000000000000104 March 2014 • Volume 42 • Number 3
cerebral venous gas embolism in the swine would not be complicated by the presence of the carotid rete, the swine may turn out to be a very suitable model for research on this topic. Dr. Weenink’s institution received grant support from Netherlands Department of Defense (grant number 009-07-5041-01). Dr. Hollmann served as a board member for Anesthesia Analgesia Editorial Board; consulted for Echo Pharmaceuticals (Weesp, The Netherlands), Eurocept, and Merck (Whitehouse Station, NJ); received grant support from International Anesthesia Research Society, ZonMW, and Nederlandse Hartstichting; and lectured for Abbott, Merck, and Pfizer. His institution received grant support from Netherlands Department of Defense (grant number 009-07-5041-01). Mr. Vrijdag, Dr. van Lienden, and Dr. de Boo’s institutions received grant support from The Netherlands Department of Defense (grant number 009-07-5041-01). Dr. Stevens lectured for and received support for development of educational presentations from Abbott and AstraZeneca. His institution received grant support from Netherlands Department of Defense (grant number 009-07-5041-01). Drs. van Gulik and van Hulst’s institutions received grant support from Netherlands Department of Defense (grant number 009-07-5041-01). Robert P. Weenink, MD, PhD, Diving Medical Center, Royal Netherlands Navy, Den Helder, The Netherlands, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Markus W. Hollmann, MD, PhD, DEAA, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Xavier C. E. Vrijdag, MSc, Department of Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Krijn P. van Lienden, MD, PhD, Diederick W. De Boo, MD, PhD, Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Markus F. Stevens, MD, PhD, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Thomas M. van Gulik, MD, PhD, Department of Surgery, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Robert A. van Hulst, MD, PhD, Diving Medical Center, Royal Netherlands Navy, Den Helder, The Netherlands, Laboratory of Experimental Intensive Care and Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands, and Department of Anaesthesiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
REFERENCE
1. Bothma PA, Rice NE: Severe Cerebral Arterial Gas Embolism Can Be Fatal; What About Cerebral Venous Gas Embolism?. Crit Care Med 2014; 42:e249–e250 DOI: 10.1097/CCM.0000000000000155
e252
www.ccmjournal.org
Obesity Paradox in Critically Ill Patients To the Editor:
I
n a recent issue of Critical Care Medicine, we have read with interest the article by Pickkers et al (1) on the obesity paradox in critically ill patients. In the last few years, a huge number of studies have been published focusing on this issue, with similar results. In the study, Pickkers et al (1) have excluded cardiac surgery patients, severe burns, and patients less than 18 years old, but recently, we have published results in obesity in patients undergoing cardiac surgery (2), which surprisingly got a mortality curve very similar to this study. It seems, therefore, that the normal weight or light-moderate obesity is protective, and underweight or morbid obesity increases mortality in critically ill patients. Pickkers et al (1) did not include patients with body mass index (BMI) greater than 55 kg/m2, and this could be the reason that no significant mortality was obtained in this group. To our knowledge, there are no severity scales such as Acute Physiology and Chronic Health Evaluation, Simplified Acute Physiology Score, Sequential Organ Failure Assessment, or European System for Cardiac Operative Risk Evaluation that include BMI or weight in its formula, except Parsonnet (3) for patients undergoing cardiac surgery. But given that we find more and more studies focusing to the protective effect on mortality in critically ill patients, maybe if we might see these items included in the score, we would improve its accuracy. The second main aspect that can be drawn is the unknown mechanism that obesity confers. Mehra et al (4) argue several explanations poorly understood, as receptors in adipocyte cells that neutralize the inflammatory cytokines, thereby reducing the systemic adverse effects (4). Following this line, some authors are trying to link inflammatory cytokines, B-type natriuretic peptide, and others measurable markers with obesity and outcomes. But at present, we do not have a study focusing such aspects in critically ill patients or severity scale involving obesity in its formula. But maybe it is a matter of time. The authors have disclosed that they do not have any potential conflicts of interest. Emilio Curiel-Balsera, MD, Juan M. Mora-Ordoñez, PhD, Javier Muñoz-Bono, PhD, Intensive Care Unit, Carlos Haya Hospital, Málaga, Spain
REFERENCES
1. Pickkers P, de Keizer N, Dusseljee J, et al: Body Mass Index Is Associated With Hospital Mortality in Critically Ill Patients: An Observational Cohort Study. Crit Care Med 2013; 41:1878–1883 2. Curiel-Balsera E, Muñoz-Bono J, Rivera-Fernández R, et al; en representación de los investigadores del proyecto ARIAM de cirugía cardiaca de adultos de Andalucía: [Consequences of obesity in outcomes after cardiac surgery. Analysis of ARIAM registry]. Med Clin (Barc) 2013; 141:100–105 3. Parsonnet V, Dean D, Bernstein AD: A method of uniform stratification of risk for evaluating the results of surgery in acquired adult heart disease. Circulation 1989; 79:I3–12 4. Mehra MR, Uber PA, Park MH, et al: Obesity and suppressed B-type natriuretic peptide levels in heart failure. J Am Coll Cardiol 2004; 43:1590–1595 DOI: 10.1097/CCM.0000000000000104 March 2014 • Volume 42 • Number 3
