HEMODYNAMICS DURING PROPOFOL NITROUS-OXIDE ANESTHESIA - EFFECTS OF PREMEDICATION WITH LORMETAZEPAM AND OF ADDITIONAL FENTANYL

  • 1 November 1987
    • journal article
    • research article
    • Vol. 36  (11) , 646-652
Abstract
Propofol, in both its new oil-in-water emulsion and the former cremophor-EL solution, is known to produce significant decreases in arterial blood pressure. The aim of this study was to obtain a precise hemodynamic profile of anesthesia induction with propofol under conditions of daily routine (additional 70% nitrous oxide) and to evaluate the influence of (1) premedication with lormetazepam and (2) additional i.v. injection of fentanyl. Forty patients (ASA classes I and II) were randomly assigned to one of four groups (A, B, C, and D). Anesthesia was induced with a sleep dose of propofol (mean: 2.4 mg/kg) and the patient was ventilated with 30% O2 and 70% N2O via a face mask. In groups B and D, 3 .mu.g/kg fentanyl were injected immediately prior to propofol injection. Patients in groups A and B received no premedication. Patients in groups C and D received 2 mg lormetazepam on the evening prior to the anesthetic and 1 mg 2 h prior to the anesthetic orally. The following parameters were determined immediately prior to induction of anesthesia and 1, 3, 5, 8, and 10 min after the start of the propofol injection: heart rate HR), mean arterial blood pressure (MAP), mean pulmonary artery pressure (PAP), central venous pressure (CVP), pulmonary occlusion pressure (POP), cardiac output (CO), stroke volume (SV), and systemic vascular resistance (SVR). In all four groups a slight decrease in HR and SVR occurred while a marked decrease in arterial blood pressure (SAP, MAP, DAP) and cardiac output was seen. PAP and preload pressures showed no significant changes. Premedication with lormetazepam had no influence on the hemodynamic pattern of anesthetic induction with propofol/N2O. With supplementary fentanyl, however, hemodynamic changes were more pronounced. The cardiovascular depression observed in this study is considered to be due to a combination of decreased cardiac output and vasodilation. Therefore, propofol should be used with caution, especially in patients in whom marked reductions in arterial blood pressure should be avoided.

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