Cutaneous heat loss with three surgical drapes, one impervious to moisture

Abstract

A new surgical drape that is impervious to moisture presumably reduces evaporative heat loss. We compared cutaneous heat loss and skin temperature in volunteers covered with this drape to two conventional surgical drapes (Large Surgical Drape and Medline Proxima). We calculated cutaneous heat loss and skin-surface temperatures from 15 area-weighted thermal flux transducers in eight volunteers. In random order, each of the drapes was evaluated with dry transducers and moistened transducers (simulating wet skin). After a 20-min uncovered control period, volunteers were covered from the neck down for 40 min. Data were recorded continuously and averaged over 10 min. Results were similar for all three drapes for dry or moist conditions. Under dry conditions, baseline heat loss was 82 +/- 14 W and decreased 30% with a surgical drape (P < 0.001). Under moist conditions, baseline heat loss was 231 +/- 45 W and decreased 29% with a drape covering (P < 0.001). Moist skin increased heat loss 282% (P < 0.001). There were no clinically important differences in skin temperature among the covers with dry or moist skin. Moist skin increased heat loss nearly three-fold, but there were no differences among the drapes. We conclude that loss is comparable with impervious and conventional drapes with either moist or dry skin.

Figures

Fig. 1

Area-weighted heat loss in watts (W) over time. Heat flux from 15 skin-surface sites was measured in W/m2 using thermal flux transducers. Flux values for each subject were converted into W/site by multiplying by estimated body surface area and assigning the same regional percentages as used for calculating mean skin temperature (see text). Using Dunnett's post-test, all heat flux values during the treatment (10, 20, 30, and 40 min) were significantly less (P < 0.001) than the initial heat flux value at time 0. However, heat loss was similar for all three drapes during both dry (open symbols) and moist (filled symbols) conditions. Data presented as means ± SDs from all 8 volunteers.

Fig. 2

Skin temperature (°C) of the volunteers over time. Area-weighted, mean skin-surface temperature was computed from measurements at 15 sites by assigning the following regional percentages to each area: head—6%, upper arms—9%, forearms—6%, hands—2.5%, fingers—2%, back—19%, chest—9.5%, abdomen—9.5%, medial thigh—6%, lateral thigh—6% posterior thigh—7%, anterior calves—7.5%, posterior calves—4%, feet—4%, and toes—2%. Skin temperatures at 10, 20, 30, and 40 min were significantly greater than at time 0 (P