All issues > Volume 38(1); 1995

Original Article

J Korean Pediatr Soc. 1995;38(1):61-65. Published online January 15, 1995.

Comparison of Graded and Bolus Infusion Methods in Baroreflex Measurements in Rabbits

Chan Uhng CU Joo¹

¹Department of Pediatrics, Chonbuk National University Medical School, Chonju, Korea

Abstract

Graded infusion and bolus injection methods of vasoactive drugs have both been used to measure baroreflex sensitivity. To determine whether the two methods produce the same values of baroreceptor sensitivity, phenylephrine and nitroglycerin was administered intravenously by both graded infusion and bolus injection methods to 11 rabbits. To evaluate the baroreflex control of heart rate(HR), a logistic sigmoid function model was used. The range of HR and baroreflex gain by the bolus method(100.53¡¾0.62, 0.113¡¾0.011) were significantly(p<0.05) larger than those measured by the graded infusion method(108.49¡¾1.66, 0.126¡¾0.013). However, there were no significant changes in the pressure at the midrange of the baroreflex curve. Thus my results indicate that baroreflex control of HR by the graded infusion and bolus injection methods is not equivalent and that baroreflex-induced HR response to a gradual change in pressure is less than that seen with a repid change.

Keywords :Baroreflex sensitivity, Heart rate, Bolus and infusion method