The effect of the short-acting barbiturate enibomal (Narcodorm) on systolic time intervals

The systolic time intervals were studied in 16 surgical patients without heart disease between 29 and 75 years of age by a non-invasive technique before and after an induction dose of enibomal (Narcodorm). The pre-injection period/left ventricular ejection time-ratio (PEP/LVET-ratio) increased between 8 and 60% and (1/PEP-2) decreased between 3 and 50%, indicating a reduction of myocardial contractility under the influence of enibomal. Factors responsible for circulatory depression during barbiturate anaesthesia are discussed.