Baroreflex function in a patient with Bartter's syndrome.

There is little information regarding circulatory responses in Bartter's syndrome, with the exception of marked resistance to vasopressors. We investigated baroreflex function in a 40-year-old woman with this syndrome. The patient showed oscillation of heart rate even with a small increase in blood pressure after administration of vasopressor agents. Variations in heart rate and blood pressure were exaggerated during halothane, nitrous oxide and oxygen anaesthesia. Although the mechanism of the unstable baroreflex in this syndrome remains to be proved, the instability may be attributable to many factors such as prostaglandins, hypovolemia, hypokalemia, halothane, nitrous oxide and positive pressure ventilation.