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Propofol causes a dose-dependent decrease in the thermoregulatory threshold for vasoconstriction but has little
K Leslie1, D I Sessler, A R Bjorksten
1Thermoregulation Research Laboratory, University of California, San Francisco.
Anesthesiology
|August 1, 1994
Summary
Propofol, an intravenous anesthetic, lowers the vasoconstriction threshold and widens the thermoregulatory range without affecting the sweating threshold. This study investigated propofol
Area of Science:
- Anesthesiology
- Physiology
- Thermoregulation
Background:
- Volatile anesthetics alter thermoregulatory responses, but intravenous anesthetic effects remain unclear.
- Autonomic thermoregulation involves sweating and vasoconstriction thresholds.
- Understanding anesthetic impact on thermoregulation is crucial for patient safety.
Purpose of the Study:
- To test if propofol increases the sweating threshold and decreases the vasoconstriction threshold.
- To determine if propofol expands the inter-threshold range.
- To investigate propofol's effects on thermoregulation using a novel model.
Main Methods:
- Six healthy males received epidural anesthesia and were administered varying propofol concentrations (0, 2, and 4 µg/ml).
- Thermal manipulations were restricted to insensate skin (legs) while sensate skin temperature was controlled.
- Sweating and vasoconstriction thresholds were measured by tympanic membrane temperature during controlled heating and cooling.
Main Results:
- Propofol caused a dose-dependent decrease in the vasoconstriction threshold.
- The sweating threshold remained largely unaffected by propofol.
- The inter-threshold range significantly increased with increasing propofol concentration.
Conclusions:
- Propofol, similar to volatile anesthetics, reduces the vasoconstriction threshold and widens the inter-threshold range.
- Unlike volatile anesthetics, propofol does not alter the sweating threshold.
- These findings highlight propofol's specific impact on thermoregulatory control.