Semi-recumbent position is the elevation of the head-of-bed to 30-45º and it is recommended for the prevention of ventilator-associated pneumonia (VAP) with almost no absolute contraindications (1). Theoretically, it is applied in most or all intensive care units (ICUs) and it is considered a “standard of care” due to its advantages of being both convenient to implement and cost-free.
In 2011, Niël-Weisse et al. (2), intended to make a more individualised recommendation on positioning, but they could only conclude that “the recommendation should not be compelling, because the prevention of VAP is uncertain and the balance between benefits and harms is unknown… The experts recommend to elevate the head of bed the bed of mechanically ventilated patients to a 20 to 45º position and preferably in >30º position as long as it does not pose risks and conflicts with other nursing tasks, medical interventions or with patients’ wishes”.
Recently, Wang et al. (3), conducted a meta-analysis to evaluate the effectiveness and safety of semi-recumbent positioning versus supine positioning to prevent VAP in adults requiring mechanical ventilation. They included only randomised clinical trials comparing semi-recumbent versus supine position (up to 10º) or other degrees of positioning. The outcomes evaluated were clinically suspected VAP, microbiologically confirmed VAP, ICU mortality, hospital mortality, length of ICU stay, length of hospital stay, duration of mechanical ventilation, antibiotic use and any adverse events. Authors included 10 trials involving 878 participants. They concluded that semi-recumbent position (30 to 60º) significantly reduced the risk of clinically suspected VAP compared to 0-10º [8 trials, Relative risk reduction 64%. Number needed to treat to benefit = 4 (every 4 patients nursed in a semi-recumbent position resulted in 1 patient free from clinically suspected VAP compared to 0-10º supine position). GRADE: Moderate quality evidence]. They did not find any statistical differences in any other outcome. In reference to the methodological issues of the studies included, most of the studies had high risk of bias and 9 out of 10 did not report the adherence to the planned position, three monitored and corrected the body position and only one trial consistently monitored the average angle of head-of-bed elevation in the semi-recumbent position group which ranged far from the target.
Authors concluded that semi-recumbent position (>30º) may reduce clinically suspected VAP compared to 0-10º supine position. However, the evidence is seriously limited with a high risk of bias. No adequate evidence is available to draw any definitive conclusion on other outcomes and the comparison of alternative semi-recumbent positions. Adverse events were under-reported. It remains uncertain which degrees of semi-recumbent position are optimal.
Article review prepared and submitted by Mireia Llaurado Serra on behalf of the N&AHP Section, ESICM.
1. Rotstein C, Evans G, Born A, Grossman R, Light RB, Magder S, et al. Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults. Can J Infect Dis Med Microbiol. 2008;19(1):19-53.
2. Niël-Weise BS, Gastmeier P, Kola A, Vonberg RP, Wille JC, van den Broek PJ. An evidence-based recommendation on bed head elevation for mechanically ventilated patients. Crit care. 2011;15(2):R111.
3. Wang L, Li X, Yang Z, Tang X, Yuan Q, Deng L, et al. Semi-recumbent position versus supine position for the prevention of ventilator associated pneumonia in adults requiring mechanical ventilation. Cochrane Database Syst Rev. 2016;(1).