Saturday, July 01, 2006

Elevation of the head of the bed- 30 or 45 degrees ?

Answer is probably 45 degrees.Elevation of the head of the bed is a must thing in ICU, unless some contra-indication. It is an essential part of VAP (ventilator associated pneumonia) bundle. But there is some debate about the extent of elevation need to be done. Accepted level is atleast 30 degrees but many guidelines wrote for 45 degrees. IHI recommends elevation anywhere from 30 to 45 degrees 3.

Study from The Netherlands 1 compared 109 patients in the supine group to 112 in the semirecumbent group. Target for semirecumbent group was 45 degrees but the targeted backrest elevation of 45° for semirecumbent positioning was not reached, so supine position (10°) was compared with achieved semirecumbent positioning (28°). Elevation of head of bed to 28° did not prevent the development of VAP.

7 years back Drakulovic and coll. published their landmark study in lancet showing 83% decrease of bacteriologically confirmed VAP in a group of patients treated in a semirecumbent position of 45° 2.

So the answer is probably 45 degrees or to be diplomatically right - atleast more than 30 degrees.

But is it easy to do and keep head of bed elevated to 45 degrees in practical world ?. The study group found that despite the presence of dedicated research nurses to control and maintain patient positioning, the semirecumbent treatment position with an aimed backrest elevation of 45° is not feasible for mechanically ventilated patients.

Another interesting question raised in discussion of first study: Is semirecumbent positioning itself a risk for VAP ? !!!, as pooling of colonized oropharyngeal fluids above the inflated cuff of the endotracheal tube is common in mechanically ventilated patients and it is possible that the semirecumbent position (and all movements to keep it) stimulates leakage of oropharyngeal fluid by means of gravity. Whether ETT with continuous aspiration of subglottic secretions (CASS) will be more effective than semirecumbent positioning?

References: Click to get article/abstract
1. Feasibility and effects of the semirecumbent position to prevent ventilator-associated pneumonia: A randomized study - Critical Care Medicine. 34(2):396-402, February 2006.
2. Supine body position as a risk factor for nosocomial pneumonia in mechanically ventilated patients: a randomised trial - Lancet.1999 Nov 27;354(9193):1851-8.
3. Elevation of the Head of the Bed - Institute for Healthcare Improvement