Mild sedation before transesophageal echo induces significant hemodynamic and respiratory depression

Midazolam is often used for conscious sedation before transesophageal echo (TEE) studies. It is not clear to what extent midazolam administration or the insertion of the TEE probe itself is responsible for the respiratory and hemodynamic depression during TEE examinations. We compared the performance of TEE with versus without midazolam to elucidate the effects of each.

Patients were given the choice of having midazolam prior to their TEE. Thirty-one patients preferred to have sedation (Sed+) and 31 others declined sedation (Sed-). Both groups had SaO(2) and blood pressure measured before the study, following sedation (in Sed+) and at the end of the TEE study.

Increase in HR was greater in Sed+ than in Sed- (12 +/- 19% vs 6 +/- 11%, both P < 0.05). There was a greater decrease in saturation of O(2) in Sed+ than in Sed- (3 +/- 3% vs 2 +/- 3%, both P < 0.05). Systolic blood pressure (SBP) increased in Sed- by 6 +/- 11% (P< 0.05) but dropped in Sed+ immediately after sedation (16 +/- 8%, P < 0.000001). Diastolic blood pressure decreased in Sed+ after sedation by 11 +/- 9% (P < 0.05).

Midazolam sedation before TEE examinations causes more prominent tachycardia and depression of SaO(2)than insertion of the TEE probe alone. It also causes a substantial drop in SBP. Midazolam should be offered only to hemodynamically stable patients without preceding respiratory depression.