Figure 40-19 Insulators readily available in most operating rooms include cotton blankets, surgical drapes, plastic sheeting, and reflective composites ("space blankets"). A single layer of each reduces total cutaneous heat loss approximately 30%, without any clinically important differences among the insulation types. Data are presented as means ± SD. (Redrawn from Sessler DI, McGuire J, Sessler AM: Perioperative thermal insulation. Anesthesiology 74:875–879, 1991.)