Reference values for left ventricular function in subjects under general anaesthesia and controlled ventilation assessed by two-dimensional transoesophageal echocardiography

Background and objective Transoesophageal echocardiography is increasingly used for evaluation and monitoring of left ventricular function in anaesthe tized patients. However, the only available reference values for transoesop hageal echocardiography were derived from studies in awake subjects. Methods We determined left ventricular dimensions and systolic function in 45 patients without clinical evidence of heart disease who voluntarily unde rwent transesophageal echocardiography under conditions of balanced general anaesthesia, controlled fluid administration, supine position, muscle rela xation and controlled ventilation. Results The left ventricular dimensions obtained during these conditions we re lower than the published normal values in awake subjects. The indices of global left ventricular function, however, were similar to the normal valu es obtained by either awake transesophageal echocardiography or transthorac ic echocardiography. Conclusion We propose using the values obtained in our study as reference v alues for evaluation of left ventricular function in patients under general anaesthesia and controlled ventilation.