Anesth Analg 2007;104:455
© 2007 International Anesthesia Research Society
doi: 10.1213/01.ane.0000253566.16527.de
LETTER TO THE EDITOR
Section Editor:
Lawrence Saidman
Alveolar Recruitment and Positive End-Expiratory Pressure in Obesity: Another Merry Chase?
Satya K. Ramachandran, MD, FRCA
Department of Anesthesiology; University of Michigan; Ann Arbor, Michigan; rsatyak{at}med.umich.edu; rsatyak{at}yahoo.com
To the Editor:
I would like to make three comments on the study by Whalen et al.
- The authors’ contention that "the significant improvements in PAo2 were caused by decreased atelectasis" is not supported by the facts. Actually, these results further support the established concept that the main determinant of oxygenation is the mean airway pressure, irrespective of positive end-expiratory pressure (PEEP) or the mode of ventilation (2).
- There is no difference in either the physiological dead-space or minute volumes required to maintain PAco2 between the two groups, suggesting that increasing PEEP is not associated with improved "ventilation," thus throwing into question the validity of optimal PEEP in obese patients.
- It is surprising that the authors chose to discuss postoperative noninvasive ventilatory modes (continuous positive airway pressure or bilevel positive airways pressure) in this context, as their use after upper gastrointestinal surgery is absolutely contraindicated.
In summary, no evidence in this study suggests any benefit from the alveolar recruitment maneuver described. Conversely, the only evidence suggests that this maneuver is associated with potential harm. Perhaps the more important issue here is the 25% incidence of postoperative pulmonary complications, which is significantly higher than the previously published incidence of 1%–2% (3).
REFERENCES
- Whalen FX, Gajic O, Thompson GB, et al. The effects of the alveolar recruitment maneuver and positive end-expiratory pressure on arterial oxygenation during laparoscopic bariatric surgery. Anesth Analg 2006;102:298–305.[Abstract/Free Full Text]
- Gattinoni L, Marcolin R, Caspani ML. Constant mean airway pressure with different patterns of positive pressure breathing during the adult respiratory distress syndrome. Bull Eur Physiopathol Respir 1985;21:275–9.[ISI][Medline]
- Dresel A, Kuhn JA, McCarty TM. Laparoscopic Roux-en-Y gastric bypass in morbidly obese and super morbidly obese patients. Am J Surg 2004;187:230–2.[ISI][Medline]
