British Journal of Anaesthesia, 1988, Vol. 60, No. 6 655-659
© 1988 The Board of Management and Trustees of the British Journal of Anaesthesia
research-article |
HAEMODYNAMIC EFFECTS OF DILTIAZEM DURING FENTANYL-NITROUS OXIDE ANAESTHESIA
An In Vivo Study in the Dog
R. M. GRIFFIN, B.M., F.F.A.R.C.S.; I. DIMICH, M.D.; R. JURADO, M.D.; J. A. KAPLAN, M.D.; Department of Anesthesiology and Division of Cardiothoracic Surgery, Mount Sinai School of Medicine, New York, NY 10029, U.S.A.
*Present address for correspondence: Anaesthetics Unit, The London Hospital Medical College, The London Hospital, Whitechapel, London E1 1BB.
The haemodynamic effects of diltiazem were studied in six dogs during fentanyl-nitrous oxide (in oxygen) anaesthesia. A bolus of diltiazem 300 µg kg1 was given, followed by infusions at 30, 60 and 90 µg kg1 min1 which produced plasma diltiazem concentrations of 392±30, 908±54 and 1483±134 ng ml1, respectively. Diltiazem significantly reduced systemic vascular resistance index, mean arterial pressure, heart rate and PR interval. The decrease in afterload increased cardiac index, since there was little change in myocardial contractility (LV dP/dt). Five dogs developed second degree atrioventricular (AV) block in association with the highest dose. Administration of calcium chloride 20 mg kg1 did not reverse the haemodynamic or electrophysiological effects of diltiazem. Isoprenaline increased heart rate and restored sinus rhythm in four dogs with AV block.
Presented in part at the 59th International Anesthesia Research Society Congress, Houston, Texas, 1985.