Background:
Epidural anesthesia decreases the core temperatures triggering vasoconstriction and shivering, presumably by increasing apparent(as opposed to actual) lower-body temperature. We therefore tested the hypothesis that epidural anesthesia in c...
Background:
Epidural anesthesia decreases the core temperatures triggering vasoconstriction and shivering, presumably by increasing apparent(as opposed to actual) lower-body temperature. We therefore tested the hypothesis that epidural anesthesia in cesarian delivery patients decreased forearm-fingertip skin-surface temperature gradient and it is cause of shivering.
Mothods:
Fifteen healthy pregnant women were studied to determine temperature changes after induction of epidural anesthesia during cesarian delivery. Epidural anesthesia was induced by 2% lidocaine and 0.75% ropivacaine 24㎖(T4 level) at 25℃ ambient temperature. Shivering or shivering-like tremor were evaluated by observation. Core temperature was recorded in the external auditory canal using a compensated infrared thermometer. Arteriovenous shunt tone was evaluated with forearm-fingertip temperature gradients; gradients less than 0 were considered evidence of vasodilation. Skin-surface temperature, skin-temperature gradients(forearm-fingertip, calf-toe) and the presence or absence of shivering or shivering-like tremor were measured.
Result:
Shivering was observed in seven of twenty two patients. Sixty minutes after induction, Tympanic temperature decreased for 0.8 ± 0.1℃ in non-shivering patients and 0.9 ± 0.1℃ in shivering patients. Forearm temperature decreased for 0.2 ± 1.7℃ in non-shivering patients, but increased for 0.5 ± 0.6℃ in shivering patients. Upper limb(Forearm-fingertip) skin temperature gradients continues the plus in non-shivering patients, but maintain minus (45 minutes after induction) in shivering patients. Low limb skin temperature is increases in both group.
Conclusion:
We failed to confirm our hypothesis, but for an expected reason: Shivering was preceded by hypothermia and vasoconstriction in the arm. For prevention of hypothermia in epidural anesthesia, Not to be monitored core temperature, but also upper limb skin temperature gradients.