The Two Hour Rule

Motivation: On the residency interview trail, I was put on a sample rotating ward team at a hospital, and one of the patients examined by the team had a significant pressure ulcer.  After examining the patient, the team talked about the importance of frequent repositioning to prevent pressure ulcers.  The standard of care is repositioning every two hours.  After listening to this case, I wondered how the figure of two hours entered clinical practice.  If I sit in the same position for even an hour, I feel pretty uncomfortable.  Turns out that the two hour guideline is partly expert opinion.  There have been some trials with inconsistent results.  Are there studies to measure effectiveness?

Paper: Frequent manual repositioning and incidence of pressure ulcers among bed-bound elderly hip fracture patients. Rich, S. et. al. Wound Repair and Regeneration (2010): 1-9.

Methods: The study examined bed-bound elderly patients 65 or older who underwent surgery for hip fracture.  During the first five days of hospitalization, study nurses assessed the frequency of repositioning through chart review.  Study nurses also determined the presence of stage 2+ pressure ulcers (at least partial thickness dermal loss or presence of blister) at baseline (within five days of hospitalization) with follow-up on alternating days for 21 days.  The study was conducted in seven hospitals in Maryland and two in Pennsylvania.

Results:

A total of 269 patients entered the study.  Overall, only 53% of patients were repositioned at least every two hours.  There was wide inter-hospital variability with repositioning rates varying from 23-77% among hospitals.  Patients most likely to be repositioned were those with pressure ulcer at time of admission.

Effect of repositioning: Pressure ulcers developed in 12% of patients repositioned frequently compared to 10% of patients repositioned less frequently.  The difference in incidence rate  was statistically not-significant (Incident Rate Ratio (IRR): 1.22 with 95% CI of 0.65-2.30).  Even after adjusting for covariates such as BMI, different support surfaces, peripheral vascular disease, nutritional status, disease severity, comorbidities, and other variables, the incident rate ratio (IRR) was not significantly, IRR: 1.12 (0.52, 2.42).

Conclusion:

In this study, frequent repositioning was not associated with reduced incidence of pressure ulcers.  In this study, there are a couple of important caveats.  The first is that the repositioning data was taken in a cross-sectional fashion in the first five days while pressure-ulcer incidence was followed for 21 days.  This technique does not capture what repositioning the patients received in the subsequent 16 days after the visit (although presumably hospitals which have repositioning in the first few days would continue the practice).  Also, the frequency of repositioning was determined from chart recordings by nurses.  The recordings may not accurately reflect the actual frequency of repositioning and may over-represent the frequency of repositioning.  Another significant finding is that the standard of care repositioning is only followed for 53% of patients despite nationwide emphasis on this issue. 

Overall, the data suggest that even with repositioning every two hours, the strategy may not be significant. Adjusting for pressure support techniques did not make a difference. Other factors such as exact position of reposition and more novel pressure support techniques may turn out to be important. While this study does not conclusively show that repositioning every two hours is ineffective, the study certainly highlights the need for a large scale randomized trial to examine the issue robustly.