Subcutaneous, muscle, and body temperatures in anesthetized man

¹ Anesthesia Laboratories, Massachusetts General Hospital, Boston, Massachusetts

Temperatures were recorded continually in 39 patients. Preinduction temperatures were, in decreasing order, (P < .01) 1) rectum and esophagus, 2) intercostal muscle, 3) gastrocnemius muscle and intercostal subcutaneous, 4) tibialis anticus muscle, and 5) tibialis anticus and gastrocnemius subcutaneous. During analgesia-muscle relaxant anesthesia, temperatures remained more stable than during deeper anesthesia. Both rectal and esophageal temperatures were unreliable indicators of the course of other temperatures. The trend of diaphragmatic temperatures suggests that the action of nondepolarizing neuromuscular blocking agents may be intensified following thoracic surgery and that of depolarizing agents prolonged and intensified following accidental hypothermia. During low spinal anesthesia, peripheral temperatures exceeded rectal temperatures for brief periods.