title: A novel method of continuous measurement of head of bed elevation in ventilated patients.
abstract: OBJECTIVE
  We developed a novel pressure transducer-based method of continuous measurement of head of bed elevation. Following validation of the method we hypothesized that head of bed angles would be at or above 30 degrees among mechanically ventilated patients throughout the day due to a hospital-wide initiative on ventilator-associated pneumonia prevention and standardized electronic order entry system to keep head of bed at an angle of 30 degrees or greater.
  
  
  METHODS
  Prospective observational study in university hospital intensive care units.
  
  
  METHODS
  Twenty-nine consecutive mechanically ventilated patients with no contraindications for semirecumbency.
  
  
  RESULTS
  We acquired 113 pairs of measurements on unused beds for validation of the method at angles between 3 degrees and 70 degrees. Correlation between transducer and protractor was fitted into a linear regression model (R2 = 0.98) with minimal variation of data along the line of equality. Bland-Altman analysis showed a mean difference of 1.6 degrees +/- 1.6 degrees. Ninety-six percent of differences were within 2 SD from the mean. This method was then used among 29 intubated patients to collect head of bed data over a 24-h period for 3 consecutive days. Contrary to our hypothesis, all patients had head of bed angles less than 30 degrees.
  
  
  CONCLUSIONS
  Our results suggest that this method could be used with high reliability and patients in our institution were not kept even at 30 degrees. The results are in accord with those of a recent study which found that continued maintenance of previously suggested head of bed angles was difficult to attain clinically. This may lead us to reevaluate methods studying the impact of head of bed elevation in VAP prevention.
authors: Department of Anesthesiology, Boston Medical Center, 88 E. Newton St. Atrium, Boston 02118, MA, USA.
authors: Konstantin
authors: K
authors: Balonov
authors: Andrew D
authors: AD
authors: Miller
authors: Alan
authors: A
authors: Lisbon
authors: A Murat
authors: AM
authors: Kaynar
mesh_terms: D001513:Beds; D003422:Critical Care; D004867:Equipment Design; D006786:Hospitals, Urban; D006801:Humans; D007362:Intensive Care Units; D008404:Massachusetts; D008991:Monitoring, Physiologic; D053717:Pneumonia, Ventilator-Associated / Q000517:prevention & control; D012121:Respiration, Artificial; D016683:Supine Position