Recruitment maneuvers during prone positioning in patients with acute respiratory distress syndrome.
OBJECTIVE
To evaluate the interaction of recruitment maneuvers and prone positioning on gas exchange and venous admixture in patients with early extrapulmonary acute respiratory distress syndrome ventilated with high levels of positive end-expiratory pressure. We hypothesized that a sustained inflation performed after 6 hrs of prone positioning would induce sustained improvement in oxygenation (Pao2/Fio2) and venous admixture.


METHODS
Prospective, interventional study.


METHODS
Tertiary care, postoperative intensive care unit.


METHODS
Fifteen patients with early extrapulmonary acute respiratory distress syndrome.


METHODS
After 6 hrs of prone positioning, a sustained inflation was performed with 50 cm H2O maintained for 30 secs. Data were recorded in supine position, after 6 hrs of prone positioning, at 3, 30, and 180 mins following the sustained inflation.


RESULTS
A response to prone positioning was observed in nine of 15 patients leading to an improvement of Pao2/Fio2 (147 +/- 37 torr vs. 225 +/- 77 torr, p = .005) and venous admixture (35.4 +/- 8.3% vs. 28.9 +/- 9.8%, p = .001). Six patients did not respond to prone positioning. Following the sustained inflation, the responders to prone positioning showed a further increase of Pao2/Fio2 and decrease of venous admixture at 3 mins (Pao2/Fio2, 225 +/- 77 torr vs. 368 +/- 90 torr, p = .018; venous admixture, 28.9 +/- 9.8% vs. 18.9 +/- 6.7%, p = .05). In all six nonresponders to prone positioning, an improvement of Pao2/Fio2 and venous admixture occurred at 3 mins following the sustained inflation (128 +/- 18 torr vs. 277 +/- 59 torr, p = .03; venous admixture, 34.2 +/- 6.0% vs. 23.8 +/- 6.3%, p = .05). The beneficial effects of the sustained inflation remained significantly elevated over 3 hrs in responders and nonresponders to prone positioning.


CONCLUSIONS
In patients with early extrapulmonary acute respiratory distress syndrome, a sustained inflation performed after 6 hrs of prone positioning induced further and sustained improvement of oxygenation and venous admixture in both responders and nonresponders to prone positioning.
Oczenski
Wolfgang
W
Department of Anesthesia and Intensive Care and the Ludwig Boltzmann Institute for Economics of Medicine in Anesthesia and Intensive Care, City of Vienna Hospital-Lainz, Vienna, Austria.
Hörmann
Christoph
C
Keller
Christian
C
Lorenzl
Norbert
N
Kepka
Anton
A
Schwarz
Sylvia
S
Fitzgerald
Robert D
RD
D000328:Adult; D000368:Aged; D000403:Airway Resistance / Q000502:physiology; D003422:Critical Care / Q000379:methods*; D005260:Female; D006801:Humans; D006874:Hydrostatic Pressure; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011175:Positive-Pressure Respiration / Q000379:methods*; D016684:Prone Position / Q000502:physiology*; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000503:physiopathology; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012128:Respiratory Distress Syndrome / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome
D010100:Oxygen