Effective dose of sedation in transesophageal echocardiography: relation to age, body surface area and left ventricle function.

BACKGROUND Sedation with midazolam and meperidine is widely used in transesophageal echocardiography. However, no mean dose is established for each individual case. OBJECTIVE To correlate the mean midazolam and meperidine doses for proper sedation for transesophageal echocardiography with age range, body surface area, and left ventricular ejection fraction. METHODS Retrospective study comprising 1,841 patients undergoing sedation based on the Ramsay scale, with a solution containing midazolam 1.5 mg (1.5 ml), meperidine 1 mg (1 ml) and distilled water (7.5 ml). Four age groups were analyzed: G1: < 24 years; G2: 25 to 44 years; G3: 45 to 64 years; and G4: > 65 years. Body surface area was calculated using the formula {[(height x 100)0.725] x (weight(0.425)) x 0.0071}. As regards the left ventricular ejection fraction, two groups were studied: GA: < 55%; and GB: > 55%. The statistical analysis was carried out using the Kruskal-Wallis test for the correlation with age and left ventricular ejection fraction, and simple linear correlation for body surface area. RESULTS As regards age, the mean doses of sedation required were significantly lower in G3 and G4 (p<0.01). The analysis of left ventricular ejection fraction showed that this was significantly lower in GA (p<0.01). The linear correlation coefficient between dose of sedation and body surface area was 0.09 (null). CONCLUSION The mean dose of sedatives required was lower in older individuals and in those with left ventricular systolic dysfunction. No correlation with body surface area was found.