Painful Stimulation Minimally Increases the Thermoregulatory Threshold for Vasoconstriction during Enflurane Anesthesia in Humans

Washington, Denna E.; Sessler, Daniel I.; McGuire, Joseph; Hynson, James M.; Schroeder, Mark E.; Moayeri, Azita

doi:10.1097/00000542-199208000-00011

Cited by 60 publications

(6 citation statements)

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“…Painful stimulation provided by a 100-Hz current increases the thermoregulatory threshold only approximately 0.4"C during enflurane anesthesia (32). However, the extent to which pain and subsequent autonomic activation contribute to thermoregulatory responses during propofoYnitrous oxide anesthesia remains unknown.…”

Section: Discussionmentioning

confidence: 99%

Thermoregulatory Vasoconstriction During Propofol/Nitrous Oxide Anesthesia in Humans

Hynson

Sessler

Belani

et al. 1992

Anesthesia & Analgesia

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To determine the thermoregulatory effects of propofol and nitrous oxide, we measured the threshold for peripheral vasoconstriction in seven volunteers over a total of 13 study days. We also evaluated the effect of vasoconstriction on oxyhemoglobin saturation (SpO2). Anesthesia was induced with an intravenous bolus dose of propofol (2 mg/kg), followed by an infusion of 180 micrograms.kg-1 x min-1 for 15 min, and maintained with 60% nitrous oxide and propofol (80-160 micrograms.kg-1 x min-1). Central and skin surface temperatures and SpO2 (using two different pulse oximeters) were measured continuously; plasma propofol concentrations and arterial PO2 were measured at 15-min intervals. Volunteers were cooled with a circulating water blanket until definitive peripheral vasoconstriction was detected. The tympanic membrane temperature triggering vasoconstriction was considered the thermoregulatory threshold. Vasoconstriction developed on seven study days during propofol/nitrous oxide anesthesia at a central temperature of 33.3 +/- 1.0 degrees C (mean +/- SD) and plasma propofol concentration of 3.9 +/- 1.1 micrograms/mL. The thresholds during anesthesia were significantly lower than those during the control period (36.7 +/- 0.3 degrees C), but the correlation between plasma propofol concentrations and vasoconstriction thresholds was poor. On the remaining six study days, vasoconstriction did not develop despite central temperatures ranging from 32.1 to 32.7 degrees C. Corresponding propofol concentrations were 4.1-10.9 micrograms/mL. These data suggest that anesthesia with propofol, in typical clinical concentrations, and 60% nitrous oxide substantially inhibits thermoregulatory vasoconstriction. Vasoconstriction increased SpO2 by approximately 2% without a significant concomitant change in PO2. The observed increase in SpO2 probably reflects decreased transmission of arterial pulsations to venous blood in the finger.

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Section: Discussionmentioning

confidence: 99%

Thermoregulatory Vasoconstriction During Propofol/Nitrous Oxide Anesthesia in Humans

Hynson

Sessler

Belani

et al. 1992

Anesthesia & Analgesia

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“…Halothane130, enflurane,131 and the combination of nitrous oxide and fentanyl132 decrease the vasoconstriction threshold 2 − 4°C from its normal value near 37°C. The effects of these drugs on sweating or shivering remain unknown, but experience with other drugs suggests that they are unlikely to have much effect on sweating, but have a profound effect on shivering.…”

Section: Thermoregulation During General Anesthesiamentioning

confidence: 99%

“…Painful stimulation slightly increases vasoconstriction thresholds131 just as pain has an anti-anesthetic effect139 and regional anesthesia has a pro-anesthetic action 140. Consequently, thresholds will be somewhat lower when surgical pain is prevented by simultaneous local or regional anesthesia.…”

Section: Thermoregulation During General Anesthesiamentioning

confidence: 99%

Temperature Monitoring and Perioperative Thermoregulation

2008

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Most clinically available thermometers accurately report the temperature of whatever tissue is being measured. The difficulty is that no reliably core-temperature measuring sites are completely non-invasive and easy to use — especially in patients not having general anesthesia. Nonetheless, temperature can be reliably measured in most patients. Body temperature should be measured in patients having general anesthesia exceeding 30 minutes in duration, and in patients having major operations under neuraxial anesthesia. Core body temperature is normally tightly regulated. All general anesthetics produce a profound dose-dependent reduction in the core temperature triggering cold defenses including arterio-venous shunt vasoconstriction and shivering. Anesthetic-induced impairment of normal thermoregulatory control, and the resulting core-to-peripheral redistribution of body heat, is the primary cause of hypothermia in most patients. Neuraxial anesthesia also impairs thermoregulatory control, although to a lesser extant than general anesthesia. Prolonged epidural analgesia is associated with hyperthermia whose cause remains unknown.

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“…[ 10 11 12 13 14 ] Midazolam slightly impairs thermoregulatory control. [ 15 ] Painful stimulation can slightly increase vasoconstriction threshold;[ 16 ] therefore, regional or local anesthesia decreases vasoconstriction threshold.…”

Section: Thermoregulation Under Anesthesiamentioning

confidence: 99%

Temperature management under general anesthesia: Compulsion or option

Bindu¹,

Bindra²,

Rath³

2017

J Anaesthesiol Clin Pharmacol

114

111

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Administration of general anesthesia requires continuous monitoring of vital parameters of the body including body temperature. However, temperature continues to be one of the least seriously monitored parameters perioperatively. Inadvertent perioperative hypothermia is a relatively common occurrence with both general and regional anesthesia and can have significant adverse impact on patients’ outcome. While guidelines for perioperative temperature management have been proposed, there are no specific guidelines regarding the best site or best modality of temperature monitoring and management intraoperatively. Various warming and cooling devices are available which help maintain perioperative normothermia. This article discusses the physiology of thermoregulation, effects of anesthesia on thermoregulation, various temperature monitoring sites and methods, perioperative warming devices, guidelines for perioperative temperature management and inadvertent temperature complications (hypothermia/hyperthermia) and measures to control it in the operating room.

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Painful Stimulation Minimally Increases the Thermoregulatory Threshold for Vasoconstriction during Enflurane Anesthesia in Humans

Cited by 60 publications

References 0 publications

Thermoregulatory Vasoconstriction During Propofol/Nitrous Oxide Anesthesia in Humans

Thermoregulatory Vasoconstriction During Propofol/Nitrous Oxide Anesthesia in Humans

Temperature Monitoring and Perioperative Thermoregulation

Temperature management under general anesthesia: Compulsion or option

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