A biomechanical model for preventing patient falls from the operating room table

Abstract

Introduction

Tilting an operating room table, though frequently needed to optimize surgical exposure, is associated with an increased risk of falls. While safety straps mitigate the risk of a fall should the patient start to slide, few tools can predict settings in which falls are likely to occur. The purpose of this study was to develop and validate a predictive biomechanical model for degree of table tilt associated with patient movement and risk of falling.

Methods

A model incorporating patient's body mass index (BMI) was designed to predict the maximum angle a table could be tilted before patient movement occurred. The model was developed using SolidWorks computer simulation and validated with 19 unrestrained, non-anesthetized volunteers. Movement on the table was self-reported and observed by the researchers as the table was tilted laterally and in reverse Trendelenburg (RT). Volunteers were categorized by BMI (“normal”: 18.5–24.9, “overweight”: 25–29.9, “obese”: >29.9). Fit of the model was assessed using mean square error, and predicted angles were compared to experimental outcomes using the Student’s t-test (P < 0.05).

Results

In both the overweight and obese BMI groups, no significant difference was noted between predicted and experimental angles. In volunteers with a normal BMI, the model underestimated the lateral angle, but accurately predicted RT. Overall, lateral angles were smaller than RT.

Conclusions

This model can predict patient sliding in the operating room, though it underestimates the maximum angle of slipping in the lateral direction among those with a normal BMI. Larger studies are needed for validation and feasibility of implementation.