Echocardiography values in the halothane uptake phase--measurement by acoustic quantification and manual evaluation

Abstract

In 35 ASA group I and II patients we investigated the influence of haemodynamic changes induced by increasing concentrations of halothane (from 0.0 to 0.6% halothane in 70% N20) on parameters of transesophageal echocardiography (TEE). Measurements by TEE were taken in manual and automatic boundary detection mode. In manual mode the left ventricular endsystolic area (ESA) increased significantly (+16.3%) and the fractional area change (FAC) decreased significantly (-14.9%). There was no significant change of left ventricular end diastolic area (EDA). In the automatic mode there was a significant increase of ESA and EDA (+13.8%; +6.0%) and a significant decrease of FAC (-10.9%). Peak ejection rate (PER) and peak filling rate (PFR) which were also assessed in automated mode decreased significantly (-10.0%; -5.7%) under halothane. No change occurred with manually determined left ventricular endsystolic wall stress (LVEWS). The endsystolic quotient decreased significantly both in manual and automated mode during halothane (-28.3%; -29.9%). No significant difference existed between TEE measurements under apnoea versus under controlled ventilation (except for EDA in automated mode). We conclude that there is no need for apnoea conditions for TEE measurements. In conclusion, TEE proves a useful monitoring system in anesthesia which enables the investigator to assess the negative inotropic effect of halothane. Problems in its practical usage are due to the wide variation of TEE measurements.