Elevation of the head of the bed is an integral part of the Ventilator Bundle and has been correlated with reduction in the rate of ventilator-associated pneumonia. The recommended elevation is 30 to 45 degrees.
Drakulovic et al. conducted a randomized controlled trial in 86 mechanically ventilated patients assigned to semi-recumbent or supine body position. The trial demonstrated that suspected cases of ventilator-associated pneumonia had an incidence of 34 percent while in the semi-recumbent position suspected cases had an incidence of 8 percent (p=0.003). Similarly, confirmed cases were 23 percent and 5 percent respectively (p=0.018). [1]
While it is not immediately clear whether the intervention aids in the prevention of ventilator-associated pneumonia by decreasing the risk of aspiration of gastrointestinal contents or oropharyngeal and nasopharyngeal secretions, this was the ostensible reason for the initial recommendation.
Another reason that the intervention was suggested was to improve patients’ ventilation. For example, patients in the supine position will have lower spontaneous tidal volumes on pressure support ventilation than those seated in an upright position. Although patients may be on mandatory modes of ventilation, the improvement in position may aid ventilatory efforts and minimize atelectasis.
Some concerns with regard to this position have included patients sliding down in bed and, if skin integrity is compromised, shearing of skin. Others have commented on the possibility of patient discomfort. Although it is difficult to assess for these concerns in a controlled manner, anecdotal experience is that neither care providers nor patients (when off the ventilator and able to speak) have had this complaint.
References:
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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. Nov 27 1999;354(9193):1851-1858.
