Blood pressure response to thermoregulatory vasoconstriction during isoflurane and desflurane anesthesia

Abstract

Background: Mild perioperative hypothermia produces morbid cardiac outcomes that may result from sympathetically induced hypertension. However, volatile anesthetics produce vasodilatation that may reduce the hemodynamic response to hypothermia. We tested the hypothesis that the volatile anesthetics isoflurane and desflurane blunt the normal cold-induced hypertensive response.

Methods: We analyzed prospective data from three analogous studies: 1) 10 volunteers given desflurane (2.6 volume percentage) maintained in left-lateral position; 2) nine volunteers without anesthesia or anesthetized with various doses of desflurane; and 3) eight volunteers given various concentrations of isoflurane. Mean skin temperature was reduced to 31 C, which decreased core body temperature and triggered thermoregulatory vasoconstriction. Mean arterial pressures were determined before and after hypothermia provoked intense thermoregulatory vasoconstriction.

Results: The hemodynamic responses to thermoregulatory vasoconstriction were similar without anesthesia and at all concentrations of desflurane and isoflurane. On average, mean arterial pressure increased 14 (SD = 5) mmHg with and without anesthesia.

Conclusion: We conclude that thermoregulatory vasoconstriction significantly increases arterial pressure with or without isoflurane or desflurane anesthesia.

Fig. 1

Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), and heart rate (HR) before and after vasoconstriction. Each symbol represents one group of study subjects. Data are represented as means of the individual studies, with the average and standard deviations for the entire study population also shown. Asterisks (*) identify statistically significant differences from vasodilatation (P < 0.001). See Table 2 for statistical analysis and detailed information.