Assessment of techniques for measuring hand pressures in mock deliveries on a mannequin

Abstract

Shoulder dystocia is a serious obstetric emergency. Brachial plexus injuries can be caused by hyperextension of the neck or misalignment of the fetal head during traction. To address knowledge gaps relating to clinician applied forces associated with deliveries, this study analyzed hand pressures applied by obstetricians in mock deliveries and suggests improvements for pressure-sensing gloves. The subjects were obstetricians, both residents and staff, recruited from the University of Kansas Hospital. A Laerdal PROMPT Birthing Simulator was used for the mock deliveries. The experimental design involved two pressure measurement strategies. Force Sensitive Applications (FSA) pressure sensitive gloves (Vista Medical) with twelve pressure sensors for each hand provided pressure measurements with time. Fujifilm Pressure Measurement Film Prescale [Two-Sheet Type for Extreme Low Pressure (4LW)] recorded areas where pressure was applied. The two measurement techniques compared well in capturing the spatial distribution of pressures across the hands. Both indicated pressure was exerted primarily with the middle, index, and ring fingers. Pressures due to the thumb and the palm were significantly smaller. Nonzero average pressures produced by the left hand were higher than the right but not significantly so. The pressure-film data indicated that pressures applied by resident and staff subgroups were comparable, except for the left hand where staff members applied significantly higher pressure with the little finger. With the glove sensors, there were three conditions: downward traction only, excessive force, which simulated conditions where damage could occur, and full delivery. The downward traction only, excessive force, and full delivery conditions had similar results with few significant differences. The residents and staff had few significant differences for these conditions between each other and between the conditions. The staff may have been more adept at using all the regions of their hands efficiently to apply balanced pressures. The glove sensors covered a range from 0 to 20 psi (0 to 0.14 MPa). If pressures exceeded the maximum of the range, the accuracy of the data decreased. This suggested that perhaps the sensor range should be improved in newer designs. Other important design changes could include increasing the numbers of sensors