[Volatile anesthetics suppress cardiac function in man; an investigation based on systolic time intervals]

Hemodynamic changes and left ventricular performance were investigated by simplified mechanocardiography using finger plethysmography instead of carotid artery pulse tracing in patients who received 4 volatile anesthetics with or without nitrous oxide. Systolic blood pressure (Ps), diastolic blood pressure (Pd), heart rate (HR), pre-ejection period (PEP), left ventricular ejection time (LVET), isovolemic contraction time (ICP), PEP/LVET, Pd/ICT, and 1/PEP2 were selected as indices which represent hemodynamics and systolic time intervals. Enflurane 0.6 and 1.2MAC prolonged PEP, and shortened 1/PEP2 and Pd/ICT significantly. Addition of nitrous oxide caused more depression. Halothane 0.6MAC prolonged PEP, and shortened 1/PEP2 and Pd/ICT. Sevoflurane 1.2MAC shortened only 1/PEP2. Addition of nitrous oxide prolonged PEP and PEP/LVET, and shortened Pd/ICT. Isoflurane 1.2MAC lowered Ps and increased HR. The results indicate that cardiac performance was depressed by volatile anesthetics in the order of enflurane, halothane, sevoflurane and isoflurane.