Submitted by Dr LAU Chun Wing Arthur on 28 April 2009

Department of Intensive Care, Pamela Youde Nethersole Eastern Hospital


Figure. Head of Bed (HOB) angle indicator used in PYNEH ICU.

Click Read More to read the evidence that this improves compliance of HOB elevation, one of the important measures to prevent ventilator-associated pneumonia (VAP).

 Simple trigonometry shows that angle HOB equals angle x (90 + x + y = 180 degrees; 90 + HOB + y = 180 degrees)


We use this device on this old mechanical bed. There are HOB angle indicators in some newer electronic beds, but not as eye-catching. There is evidence that this simple device improves HOB elevation compliance.



Williams, Zev MD, PhD; Chan, Rodney MD; Kelly, Edward MD. Critical Care Medicine. 36(4):1155-1157, April 2008. A simple device to increase rates of compliance in maintaining 30-degree head-of-bed elevation in ventilated patients. 

Fulltext available here.

Objective: To determine whether a highly visible device that clearly indicates whether the head-of-bed is adequately elevated would increase rates of compliance with head-of-bed elevation guidelines.

Design: A prospective, single-center, multi-unit, two-phase study.

Setting: Surgical, thoracic, trauma, and medical intensive care units.

Patients: Cohort of intubated patients.

Interventions: A 4-wk trial was performed. At the onset of the trial, nurses were reminded to maintain head-of-bed elevation >30 degrees. Over the subsequent 2 wks, head-of-bed elevations of intubated patient beds were measured. An Angle Indicator, designed to clearly display whether the head-of-bed was adequately elevated, was then placed on side rails of beds of ventilated patients, and head-of-bed elevation measurements were taken for an additional 2 wks. A survey was then handed out to nursing staff to assess satisfaction with the device.

Measurements and Main Results: A total of 268 bed measurements were made. The average head-of-bed elevation was 21.8 degrees on beds without the device (n = 166) and 30.9 degrees on beds with the device (n = 102; p < .005). When compliance is defined as a bed angle of >=28 degrees, 23% of beds without the device were compliant while 71.5% of the beds with the device were compliant. The relative risk and odds ratio of having the device on a compliant bed were 2.2 and 9.25, respectively (p < .005). Seventy-two percent of nurses surveyed (n = 32) found it to be an improvement over existing methods, 88% found it helpful, and 84% would like it routinely used.

Conclusions: The Angle Indicator improved rates of adherence to bed-elevation guidelines, and hospital staff found it helpful.