Prone positioning in patients with moderate and severe acute respiratory distress syndrome: a randomized controlled trial.
BACKGROUND
Post hoc analysis of a previous trial has suggested that prone positioning may improve survival in patients with severe hypoxemia and with acute respiratory distress syndrome (ARDS).


OBJECTIVE
To assess possible outcome benefits of prone positioning in patients with moderate and severe hypoxemia who are affected by ARDS.


METHODS
The Prone-Supine II Study, a multicenter, unblinded, randomized controlled trial conducted in 23 centers in Italy and 2 in Spain. Patients were 342 adults with ARDS receiving mechanical ventilation, enrolled from February 2004 through June 2008 and prospectively stratified into subgroups with moderate (n = 192) and severe (n = 150) hypoxemia.


METHODS
Patients were randomized to undergo supine (n = 174) or prone (20 hours per day; n = 168) positioning during ventilation.


METHODS
The primary outcome was 28-day all-cause mortality. Secondary outcomes were 6-month mortality and mortality at intensive care unit discharge, organ dysfunctions, and the complication rate related to prone positioning.


RESULTS
Prone and supine patients from the entire study population had similar 28-day (31.0% vs 32.8%; relative risk [RR], 0.97; 95% confidence interval [CI], 0.84-1.13; P = .72) and 6-month (47.0% vs 52.3%; RR, 0.90; 95% CI, 0.73-1.11; P = .33) mortality rates, despite significantly higher complication rates in the prone group. Outcomes were also similar for patients with moderate hypoxemia in the prone and supine groups at 28 days (25.5% vs 22.5%; RR, 1.04; 95% CI, 0.89-1.22; P = .62) and at 6 months (42.6% vs 43.9%; RR, 0.98; 95% CI, 0.76-1.25; P = .85). The 28-day mortality of patients with severe hypoxemia was 37.8% in the prone and 46.1% in the supine group (RR, 0.87; 95% CI, 0.66-1.14; P = .31), while their 6-month mortality was 52.7% and 63.2%, respectively (RR, 0.78; 95% CI, 0.53-1.14; P = .19).


CONCLUSIONS
Data from this study indicate that prone positioning does not provide significant survival benefit in patients with ARDS or in subgroups of patients with moderate and severe hypoxemia.


BACKGROUND
clinicaltrials.gov Identifier: NCT00159939.
Taccone
Paolo
P
Dipartimento di Anestesia e Rianimazione, Fondazione IRCCS-Ospedale Maggiore Policlinico, Mangiagalli, Regina Elena di Milano, 20122 Milan, Italy.
Pesenti
Antonio
A
Latini
Roberto
R
Polli
Federico
F
Vagginelli
Federica
F
Mietto
Cristina
C
Caspani
Luisa
L
Raimondi
Ferdinando
F
Bordone
Giovanni
G
Iapichino
Gaetano
G
Mancebo
Jordi
J
Guérin
Claude
C
Ayzac
Louis
L
Blanch
Lluis
L
Fumagalli
Roberto
R
Tognoni
Gianni
G
Gattinoni
Luciano
L
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000628:therapy; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016684:Prone Position; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000401:mortality / Q000628:therapy*