CARDIOVASCULAR EFFECTS OF IV INDUCTION IN CHILDREN - COMPARISON BETWEEN PROPOFOL AND THIOPENTONE

We have compared the haemodynamic responses to i.v. propofol 2.5 mg kg -1 with those to thiopentone 5.0 mg kg-1 in 41 healthy Chinese childre n at induction of anaesthesia. They were allocated to four groups acco rding to their age and induction agent received: group 1 < 2 yr, propo fol, n = 9; group II < 2 yr, thiopentone, n = 9; group III 2-12 yr, pr opofol, n = 12; group IV 2-12 yr, thiopentone, n = 11. Anaesthesia was maintained by spontaneous ventilation with 70% nitrous oxide and 0.5% halothane in oxygen. Arterial pressure and heart rate were monitored by automatic oscillotonometer. Stroke volume was measured by two-dimen sional echocardiography and pulse Doppler. Measurements were made befo re induction and at 1-min intervals for 5 min after induction. The red uction in mean arterial pressure was significantly greater after propo fol (28-31%) than after thiopentone (14-21%) (P = 0.00 1). The reducti on in cardiac index (10-15%) after induction was not significantly dif ferent between the two agents (P = 0. 122). Baroreflex mediated increa ses in heart rate and systemic vascular resistance were less after pro pofol than after thiopentone. The baroreceptor reflex was more attenua ted in children aged less than 2 yr than in older children.