Influence of low tidal volumes on gas exchange in acute respiratory distress syndrome and the role of recruitment maneuvers.
BACKGROUND Use of a low tidal volume (V(T)) strategy in the treatment of acute respiratory distress syndrome can lead to a decrease in oxygenation. This study evaluated the safety and efficacy of a recruitment maneuver (RM) in this setting.


METHODS
Twelve patients with acute respiratory distress syndrome were studied within 48 hours of diagnosis. Baseline gas exchange, hemodynamics, and respiratory mechanics were determined and patients were placed on a V(T) of 6 mL/kg. Measurements were repeated and an RM of 30 cm H20 for 40 seconds was performed. Measurements were repeated at 30 minutes and 2 hours post-RM.


RESULTS
Decreasing V(T) resulted in a decrease in arterial oxygenation (from 91 +/- 9 mm Hg to 75 +/- 9 mm Hg, p < 0.01), an increase in shunt (from 19 +/- 3.7% to 23 +/- 5%, p < 0.01), and a decrease in lung compliance (from 37 mL/cm H2O to 33 mL/cm H2O, < 0.05). At 30 minutes post-RM, oxygenation improved to 99 +/- 16 mm Hg, shunt decreased to 17 +/- 3%, and lung compliance improved to 39 mL/cm H2O (p < 0.05). Two hours later, oxygenation fell (86 +/- 12 mm Hg), shunt increased (20 +/- 3%), and compliance diminished (36 mL/cm H2O). There were no hemodynamic or barotraumatic complications.


CONCLUSIONS
An RM transiently improves gas exchange during low V(T)ventilation. RMs are well tolerated and no hemodynamic consequences were seen.
Johannigman
Jay A
JA
Department of Surgery, University of Cincinnati, Ohio 45267-0558, USA. jay.johannigman@uc.edu
Miller
Sandra L
SL
Davis
Bradley R
BR
Davis
Kenneth
K
Campbell
Robert S
RS
Branson
Richard D
RD
D000063:Accidents, Traffic; D000328:Adult; D000368:Aged; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009104:Multiple Trauma / Q000209:etiology / Q000628:therapy*; D011175:Positive-Pressure Respiration; D011659:Pulmonary Gas Exchange; D012128:Respiratory Distress Syndrome / Q000209:etiology / Q000628:therapy*; D013990:Tidal Volume