Left ventricular ejection fraction, end-diastolic volume and endsystolic volume during induction of anaesthesia

Abstract

: Left ventricular ejection fraction, end–diastolic volume and end–systolic volume were determined in 74 patients with ischaemic heart disease (IHD), during induction of anaesthesia, using different anaesthetic techniques. Ejection fraction measured with nuclear angiocardiography (Nuclear Stethoscope), was combined with stroke volume, determined with thermodi–lution, to calculate end–diastolic volume and end–systolic volume. Together with pressure measurements, the left ventricular pressure–volume relationship in end–distole and end–systole could be evaluated. Left ventricular diameter, determined with transthoracic 2D echocardiography, was subsequently studied during induction of anaesthesia in 11 patients with IHD. The results from this study were compared with the findings of previous studies. In a further study the relationship between pressure readings in the ascending aorta and the radial artery was investigated during anaesthesia in 26 patients with IHD. Special reference was made to the relationship between aortic and radial artery dicrotic notch pressure. Conclusions: 1. Induction of anaesthesia with hypnotics, low dose fentanyl and pancuronium caused a considerable decrease in left ventricular preload, estimated as end–diastolic volume (I, III, V). 2. Induction of anaesthesia with isoflurane and nitrous oxide in combination with hypnotics, low dose fentanyl and pancuronium, caused a similar reduction in preload (II). 3. The decrease in preload, during induction of anaesthesia with the low dose fentanyl techniques, was of the same magnitude (31–45%), despite the use of several different drug combinations (I, II, III, V). 4. In addition to the decrease in end–diastolic volume, there was a decrease in end–systolic volume during induction of anaesthesia in the low dose fentanyl groups. The net result was an increase in ejection fraction and a decrease in stroke volume (I, II, III). 5. Laryngoscopy and intubation caused a decrease in left ventricular ejection fraction and an increase in end–diastolic and end–systolic volume in the low dose fentanyl groups (I, II, III). 6. Nitroglycerin as an iv bolus effectively prevented the decrease in ejection fraction and the increase in end–diastolic and end–systolic volume during laryngoscopy and intubation, during induction of anaesthesia with a low dose fentanyl technique (III). 7. Left ventricular filling pressure was poorly correlated to left ventricular enddiastolic volume (I, II, III). 8. A high dose fentanyl technique in combination with pancuronium implied stable haemodynamics, with reference to left ventricular ejection fraction, enddiastolic volume and end–systolic volume, during induction of anaesthesia including laryngoscopy and intubation (I). 9. Left ventricular end–systolic pressure, measured as the dicrotic notch pressure in the ascending aorta, could be estimated from pressure measurements in the radial artery, with reasonable accuracy, in the period immediatley preceding cardio–pulmonary bypass (IV). 10. The estimated changes in left ventricular end–diastolic and end–systolic volume, during induction of anaesthesia, were similar using two different techniques of measurement: therrnodilution in combination with nuclear angiocardiography (I, II, III) and transthoracic echocardiography (V).