PURPOSE: Ventilator associated pneumonia (VAP) represents a significant challenge in the ICU; recent efforts have focused on preventing VAP. Elevation of the head of bed (HOB) has been shown to be effective at reducing the development of VAP. The optimum angle of HOB elevation is unknown. We sought to compare 30 vs. 45 degrees HOB elevation with regards to reducing the magnitude of gastroesophageal reflux and pulmonary aspiration.
METHODS: This is a prospective randomized cross-over trial involving mechanically ventilated ICU patients receiving enteral feeds. Each subject is studied at both 30 & 45 degrees. Subjects were placed at the prescribed HOB angle and Tc-99m labeled sulfur colloid was instilled via their feeding tube. Samples of secretions from the posterior oropharynx (OP) and the endotracheal suction catheter (ET) were taken at baseline then 2 & 5 hours later and analyzed for radioactivity (RAc) expressed as log10 cpm. The procedure was repeated in the alternate HOB angle 48 hours later. OP & ET RAc counts from 30 & 45 degrees were compared.
RESULTS: To date 5 subjects have completed the trial. Mean age was 56 year, indications for mechanical ventilation included sepsis (3), cardiogenic shock (1) & trauma (1). Mean APACHE II score was 15 (range 11-18). Mean 2 & 5 hour OP RAc were 3.8 and 4.3 at 30 degrees & 4.2 and 4.1 at 45 degrees. Mean ET RAc was 3.3 and 2.9 at 30 degrees and 2.1 and 3.0 at 45 degrees.
CONCLUSION: Our data suggest that there is no difference between 30 & 45 HOB elevation in terms of OP RAc (gastroesophageal reflux) and ET RAc (aspiration). Despite professional society recommendations, prior studies have shown that achieving & maintaining 45 HOB elevation is difficult.
CLINICAL IMPLICATIONS: Clinicians should target 30 degrees HOB elevation; this may be more achievable in a real world ICU setting. Further trials are warranted to assess the clinical usefulness of 30 degrees HOB elevation in an outcome study.
DISCLOSURE: David De Blasio, None.