Preanesthetic Skin-Surface Warming Reduces Redistribution Hypothermia Caused by Epidural Block

Abstract

Redistribution of heat from the core to the cool peripheral compartments of the body causes hypothermia during epidural anesthesia. Diminishing the temperature gradient between the core and peripheral tissues by warming the body via the skin before anesthesia should prevent this hypothermia. We measured core temperature, skin temperatures, and cutaneous heat loss in seven volunteers who received two lidocaine epidural injections during a single study day. One epidural injection was given after the volunteer had rested in a cool room (approximately 22 degrees C) ("no prewarming") for 2 h, and one injection was given after the volunteer had been covered with a forced air warming mattress (approximately 38 degrees C) ("prewarming") for 2 h. Skin temperatures were higher after prewarming. The decrease in core temperature during epidural anesthesia was smaller after prewarming [mean within patient difference (prewarming-no prewarming): 0.41; P = 0.003]. However, heat loss was greater after prewarming (mean within patient difference: 26.4; P = 0.02). Shivering was less after prewarming. We conclude that prewarming decreases redistribution hypothermia caused by epidural block. These results support the hypothesis that redistribution of heat within the body, not heat loss, is the most important etiology of hypothermia from epidural anesthesia.

Preoperative warming combined with intraoperative skin-surface warming does not avoid hypothermia caused by spinal anesthesia in patients with midazolam premedication

“…Intraoperative data for the three groups of patients that received preoperative midazolam neuraxial anesthesia. 16 Preemptive skin-surface warming is effective and rapidly increases core temperature and body heat content, as demonstrated in our study and in other studies. [14][15][16][17] Our gain in heat content through preinduction treatment (543 ± 216 kJ) is consistent with the findings from a previous study on heat storage in the human body.…”

“…16 Preemptive skin-surface warming is effective and rapidly increases core temperature and body heat content, as demonstrated in our study and in other studies. [14][15][16][17] Our gain in heat content through preinduction treatment (543 ± 216 kJ) is consistent with the findings from a previous study on heat storage in the human body. 17 Spinal anesthesia inhibits thermoregulatory control centrally, 21 but a far more important effect of neuraxial anesthesia is the blocking of peripheral sympathetic and mo- reaching 445 ± 223 kJ in Gintra and 329 ± 208 kJ in Gpre+intra at the end of the surgery.…”

“…7,8 Intraoperative hypothermia often induces adverse outcomes, including coagulopathy and increased blood loss, 9 surgical wound infections and prolonged hospitalization, 10 intraoperative and postoperative cardiac events, 11 discomfort 12 and postoperative shivering. 13 One to two hours of active skin-surface warming before inducing general 14,15 and epidural anesthesia 16 minimizes intraoperative hypothermia. Such prolonged prewarming is, however, impractical in most hospitals.…”

The effect of short time periods of pre‐operative warming in the prevention of peri‐operative hypothermia

“…Avoiding peri-operative hypothermia still remains challenging. From the first studies describing the beneficial effects of pre-warming in 1993 [7][8][9] there was a period of 16 years until pre-operative warming was implemented as a standard procedure in clinical guidelines. In 2009, Forbes et al advocated a multidisciplinary team approach of surgeons, anaesthesiologists and nurses, and recommended using forced-air and intravenous fluid warming systems and raising room temperature to 22°C [2], for surgical procedures with expected duration > 30 min.…”

Comparison of efficacy of ketamine, midazolam and ketamine plus midazolam for prevention of shivering under spinal anaesthesia

“…This problem is seen in up to 57% of patients receiving spinal anesthesia. 1,2 Shivering is a physiologically stressful and undesirable outcome for a patient although its main role is to provide heat. However, its occurrence in relation to anesthesia is not completely understood.…”