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The effect of nursing position in mechanically ventilated patients in ICU on the incidence of ventilator associated pneumonia (VAP)

Citation/s:
Drakulovic MB. Torres A. Bauer TT. Nicolas JM. Nogue S. Ferrer M. Supine body position as a risk factor for nosocomial pneumonia in mechanically ventilated patients: a randomised trial. Lancet. 354(9193):1851-8, 1999 Nov 27.

Lead author's name and fax: Dr Antoni Torres atorres@medicina.ub.es

Three-part Clinical Question: In mechanically ventilated patients in ICU, does nursing in the semirecumbent position reduce the risk of VAP.
Search Terms: ventilator associated pneumonia, pneumonia, ICU, prevention, randomised trial, semirecumbent

The Study:
Non-blinded concealed randomised controlled trial without intention-to-treat.
The Study Patients: Mechanically ventilated patients in a 6-bed respiratory ICU and an 8-bed medical ICU in a 1000-bed tertiary-care university hospital. Entry was on intubation or admission to ICU. Exclusion criteria were: recent abdominal surgery (< 7 days), recent neurosurgical intervention (< 7 days), shock refractory to vasoactive drugs or volume therapy, and previous endotracheal intubation (< 30 days). All consecutive patients were included and randomised. The control group were slightly older, sicker and ventilated for longer although none of these parameters reached statistical significance
Control group (N = 47; 47 analysed): Patients were nursed in the supine position (0 degrees) till the first weaning trial, extubation, permanent change in body position for more than 45 min or death.
Experimental group (N = 43; 39 analysed): Patients were nursed in the semi-recumbent position (45 degrees) till the first weaning trial, extubation, permanent change in body position for more than 45 min or death. Surveillance for clinical detection was done daily. Samples for microbiological test were taken if infection was clinically suspected. This was done by tracheobronchial aspiration, BAL or protected specimen brush. 

The Evidence:

Comments:
This is the only outcome paper published to date looking at the effect of nursing position on the incidence of VAP. The calculated sample size was 180 although the trial was stopped after the first interim analysis; 90 patients were recruited although only 86 were analysed.

Although position was checked "daily" and staff were instructed not to change the position unless for medical requirements, there is no way of knowing whether the 45 degrees was achieved all the time. Because of the obvious difficulty in blinding a study like this, there might have been bias in diagnosing clinically suspected pneumonia, although standard CDC criteria were used for the diagnosis. No information is given on the pathogens recovered that made microbiological confirmation possible, although definitions of microbiologically proven pneumonia are given.

The incidence of VAP was 22% for the study population. The incidence of VAP was particularly high, 50%, for patients who were enterally fed and nursed in the supine position. While incidence was only 9% for enterally fed patients nursed in the semi-recumbent position. This finding is significant considering the current trend towards enteral feeding.

Prolonged mechanical ventilation and GCS < 9 were additional risk factors.

Appraised by: Mo Al-Haddad Royal Infirmary of Edinburgh; 12 June 2003
Email: malhaddad@yahoo.com

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Kill or Update By: June 2005

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