The effect of skin surface warming on pre-operative anxiety in neurosurgery patients.

Abstract

Skin surface warming of patients not only improves thermal comfort, but has been shown to reduce anxiety in a pre-hospital setting. We tested the hypothesis that pre-operative warming can reduce pre-operative anxiety as effectively as a conventional dose of intravenous midazolam in patients undergoing neurosurgery. We randomly allocated 80 patients to four groups in the pre-operative holding area. Treatment was applied for 30-45 min with (1) passive insulation and placebo; (2) passive insulation and intravenous midazolam (30 microg.kg-1); (3) warming with forced-air and placebo; and (4) warming with forced-air and intravenous midazolam (30 microg.kg-1). Thermal comfort levels (VAS 0-100 mm) and anxiety levels (VAS 0-100 mm, Spielberger State-Trait Anxiety Inventory) were assessed twice: before the designated treatment was started and before induction of anaesthesia. In the midazolam and the midazolam/warming groups, anxiety VAS and Spielberger state anxiety scores decreased by -19 (95% CI: -29 to -9, p<0.01) and -10 (95% CI: -14 to -6, p<0.01), respectively. In the warming and the combined groups, thermal VAS increased by +26 (95% CI: 17-34, p<0.01). Pre-operative warming did not reduce anxiety VAS (p=0.11) or Spielberger state anxiety (p=0.19). The results of our study indicate that pre-operative warming can be recommended solely to improve thermal comfort, not to replace anxiolytic premedication regimens.