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A semirecumbent body position produced a lower rate of nosocomial pneumonia than did a supine position in mechanically ventilated adults


ACP J Club. 2000 May-June;132:89. doi:10.7326/ACPJC-2000-132-3-089

Source Citation

Drakulovic MB, Torres A, Bauer TT, et al. Supine body position as a risk factor for nosocomial pneumonia in mechanically ventilated patients: a randomised trial. Lancet. 1999;354:1851-8. [PubMed ID: 10584721]



In patients who are intubated and mechanically ventilated, is a semirecumbent body position more effective than a supine body position for reducing the incidence of nosocomial pneumonia?


Randomized (allocation concealed*), unblinded,* controlled trial with follow-up to 72 hours after extubation. An interim analysis was planned.


2 intensive care units (ICUs) of a 1000-bed, tertiary care, university hospital in Spain.


90 patients (mean age 65 y, 76% men) in the ICU who had been intubated and mechanically ventilated. Exclusion criteria were recent abdominal surgery or neurosurgery, shock refractory to fluids or inotropes, or previous endotracheal intubation. 96% of patients completed the trial.


43 patients were allocated to a semirecumbent body position (45° from the horizontal) and 47 to a supine body position.

Main outcome measures

Clinically suspected nosocomial pneumonia. Secondary outcome was microbiological nosocomial pneumonia confirmed by bronchoalveolar lavage or protected specimen-brush cultures.

Main results

The study was stopped early when analysis showed that the semirecumbent position was superior. Fewer patients in the semirecumbent group developed clinically suspected (P = 0.003) or microbiologically confirmed (P = 0.018) nosocomial pneumonia than in the supine group (Table). The groups did not differ for mortality (18% in the semirecumbent group vs 28% in the supine group, P = 0.3).


For patients in the intensive care unit who were mechanically ventilated, a semirecumbent body position was associated with a lower rate of nosocomial pneumonia than was a supine position.

*See Glossary.

Sources of funding: Commisionat per a Universitats i Recerca de la Generalitat de Catalunya 1997 Suport dels Grups de Recerca; Fundació Clinic; Comissió Interdepartamental de Recerca i Innovació Tecnológica; IDIBAPS; European Respiratory Society.

For correspondence: Dr. A. Torres, Hospital Clinic i Provincial, Servei de Pneumologia i Allèrgia Respiratoria, Villarroel, 170, E-08036 Barcelona, Spain. FAX 34-93-2275454.

Table. Semirecumbent vs supine body position for prevention of nosocomial pneumonia 72 hours after extubation†

Pneumonia Semirecumbent Supine RRR (95% CI) NNT (CI)
Clinically suspected 8% 34% 77% (35 to 93) 4 (3 to 11)
Microbiologically confirmed 5% 23% 78% (19 to 94) 6 (4 to 29)

†Abbreviations defined in Glossary; RRR, NNT, and CI calculated from data in article.


Previous randomized trials comparing supine with semirecumbent positioning have evaluated surrogate outcomes for pneumonia. Torres and Orozco-Levi and their colleagues (1) found higher radioactive counts in endobronchial secretions in patients who were supine rather than semirecumbent. Ibanez and colleagues (3) found more scintigraphic evidence of esophageal reflux in patients in the supine position.

The trial by Drakulovic and colleagues used the outcome of nosocomial pneumonia. This trial was randomized, the allocation was concealed, and the patients were similar at baseline. Obviously, blinding the ICU team to body position was not possible, which made the objective definitions of pneumonia very important. Some co-interventions were similar between groups. No patients received frequent ventilator circuit changes or selective digestive decontamination, and all had sterile endotracheal suctioning. However, the ICU team decided whether to use enteral feeding. Sucralfate was used as a stress ulcer prophylaxis for patients receiving enteral nutrition; ranitidine or omeprazole was used for patients who were not. In terms of generalizability, the patients in the study are well described, the exclusion criteria are clear, and the intervention is affordable.

One important interaction between enteral nutrition and supine body position was found. Clinically suspected pneumonia was highest (50%) when enteral feeding was given in the supine position compared with 9% for enteral feeding in the semirecumbent position, 10% for no enteral feeding in the supine position, and 6% for no enteral feeding in the semirecumbent position (P < 0.001).

In the absence of contraindications (e.g., ionotrope independence) or competing alternative positions (e.g., proning), semirecumbency appears to be a low-technology, implementable pneumonia prevention strategy for patients who are mechanically ventilated, especially those receiving general nutrition.

Deborah J. Cook, MD
McMaster University Faculty of Health Sciences
Hamilton, Ontario, Canada


1. Torres A, Serra-Batlles J, Ros E, et al. Pulmonary aspiration of gastric contents in patients receiving mechanical ventilation: the effect of body position. Ann Intern Med. 1992;116:540-3. [PubMed ID: 1543307]

2. Orozco-Levi M, Torres A, Ferrer M, et al. Semirecumbent position protects from pulmonary aspiration but not completely from gastroesophageal reflux in mechanically ventilated patients. Am J Respir Crit Care Med. 1995;152:1387-90. [PubMed ID: 7551400]

3. Ibáñez J, Peñafiel A, Raurich JM, et al. Gastroesophageal reflux in intubated patients receiving enteral nutrition: effect of supine and semirecumbent positions. JPEN J Parenter Enteral Nutr. 1992;16:419-22. [PubMed ID: 1433774]