Dobutamine infusion modifies thermoregulation during general anesthesia.

A redistribution of body heat from core to peripheral tissues causes a rapid decrease in core temperature. The present study tested whether a dobutamine infusion would facilitate redistribution and induce a further decrease in core temperature. Volunteers were randomly assigned to the control group (n = 8) and the experimental group (n = 8). They were anesthetized with isoflurane at an end-tidal concentration of near 1.2% for 120 min. In the experimental group, dobutamine was infused at a rate of 4 micrograms.kg-1.min-1. Core temperature, skin temperature, tissue temperature, and laser-Doppler perfusion index were measured. Leg heat content was calculated by morphometric data and observed temperatures. The decrease in leg heat content was larger in the control group than in the experimental group 30 min after anesthetic induction (P < 0.05). In contrast, the core temperature decreased further in the dobutamine group than in the control group 40 min after induction (P < 0.05). Dobutamine induced further hypothermia, presumably by facilitating heat transfer and by increasing cutaneous heat loss. Hypothermia will be increased when using dobutamine for anesthesia.