A Changes in Blood Pressure with Varying Rates of Adminstration of d-Tubocurarine / 대한마취과학회지

ABSTRACT

d-tubocurarine is one of the non-depolarizing muscle relaxants which is most commonly used in clinical situations d-Tc is used as a selective muscle relaxant in hypertensive patients or patients for renal transplantation. The most common side effect of d-Tc is a dose-related fall in arterial pressure. Although the cause of the hypotension is still controversial, the two mechanism most frequently suggested are ganglionic block and histamine release. d-Tc is an active ganglionic blocking agent. Howver, because its potency at the neuromuscular junction is greater than at the ganglia, there is some doubt that a clinical concentration of d-Tc is sufficient to cause hypotension. histamine release may play a role in this blood pressure reduction. Indeed, decrease in blood pressure produced by d-Tc have been shown to be less when the muscle relaxant was preceded by and antihistamine. The amount of histamine release substance depends on plasma levels of the drug achieved and thus on the rapidity of intravenous administration of that drug. If d-Tc produces histamine release, then slow intravenous injection would be associated with minimal histamine release and a resulting attenuation of the typical blood pressure reduction that follows' this drugs injection. Therefore, we measured changes in mean arterial pressure(MAP) and heart rate in patients anesthetized with nitrous oxide-halothane during and after the intravenous injection of d-Tc at varying rates of administration. The results are as follows 1) Group 1 Maximum reduction in MAP were present 3 minutes following d-Tc injection over 1 second (81+/- 3 torr). Comparative with control group (99+/-6 torr), significant reduction was revealed(18.1%). 2) Group 2 Decrease in MAP 3 minutes after administration of d-Tc over 90 seconds(11.1%) were intermediate between the other injection rates. 3) Group 2 Decrease in MAP 3 minutes after d-Tc administration was significantly less in patients receiving the drug over 180 seconds(5.1%). Heart rate did not change significantly after d-Tc injection regardless of the rate of administration.