307 MEAN ARTERIAL BLOOD PRESSURE (MAP) RESPONSE TO PAN-CURONIUM BROMIDE (PB) IN THE NEWBORN PIGLET

Abstract

Pharmacological induction of muscle paralysis with PB is frequently used in the newborn to facilitate artificial ventilation. Cardiovascular responses to this drug have not been as well documented in the neonate as in the adult. Sixteen newborn piglets (wt 800-2300 gms) were anesthetized with ketamine (IM) and placed on a Bourns LS-105 ventilator. Heart rate, systolic, diastolic and MAP were continuously monitored. PB was given IV in varying dosages (.03-.72 mg/kg)for induction of complete paralysis. Acid-base imbalance (pH 7.03-7.65) was produced by altering ventilator settings and by lactic acid infusion. Fifty-eight percent of PB injections resulted in an increased MAP (↑X 12.9 mmHg),9% lowered MAP(↓X 16 mmHg)and in the remaining 32%,MAP continued unchanged. The following variables were also analyzed: weight, drug dosage, blood pH and change in heart rate (HR). Analysis of variance revealed that HR changes were the only statistically significant variable (p<.05). A significant rise in HR was noted with either an increase or decrease in MAP, while the HR remained relatively constant when MAP was unchanged. In adults, PB increases HR and MAP; however, in the newborn piglet, the response to PB is variable. Alterations in MAP have significant effects on tissue-organ blood flow. If the variable HR and MAP responses to PB seen in the newborn animal model can be extrapolated to humans, careful monitoring of cardiovascular function is advisable in neonates undergoing muscle paralysis.