Effects of Curvilinear Supine Position on Tissue Interface Pressure: A Prospective Before-and-After Study.

Abstract

To determine whether a curvilinear supine position increases the contact area between the subject and the surgical table, reduces interface pressures within contact areas, and improves comfort. This observational study was completed to establish proof-of-concept to determine differences between 2 positions (supine and curvilinear) on interface pressure of 5 at-risk anatomical locations, overall contact area, and subjects' comfort level. The study was conducted at the operating theater of a tertiary teaching hospital in Wuhan, China. The sample comprised 145 healthy Asian volunteers between 18 and 60 years of age. Subjects were placed in the supine and curvilinear supine positions on a surgical table. Contact area and peak interface pressures of 5 at-risk anatomical locations (occiput, scapula, sacrum, calf, and heel) were measured using a pressure mapping system, and the mean and maximum pressures of the overall contact area were calculated. Comfort was assessed by self-report using a Likert scale of 1 to 5. The Wilcoxon paired signed rank test was used to compare differences between the 2 positions, and the Spearman correlation analysis was used to identify associations among outcome variables. Results indicated that whole-body (overall) maximum, average interface pressures, and maximum interface pressures of the sacrum and the heel were decreased significantly, with contact area and comfort-level score increasing from 2438.71 to 2709.68 cm and 3.00 to 4.00, respectively (P < .001). Statistically significant associations were found between the contact area and measures of body morphology; correlation coefficients varied from 0.409 to 0.740 (P < .001). Curvilinear supine position increased overall contact area with the support surface, reduced interface pressures over contact areas (bony prominences), improved comfort, and enhanced pressure redistribution. Additional research is needed to determine if these effects will reduce intraoperative pressure injury occurrence.