Journal of anesthesia
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Journal of anesthesia · Jun 1997
Oral clonidine premedication does not alter the efficacy of epidural test doses in adult patients anesthetized with isoflurane.
Clonidine premedication has been increasingly used in clinical anesthesia. Though clonidine was found to alter pressor responses to various sympathomimetics, its effect on epidural test dose efficacy to detect intravascular injection has never been evaluated. Eighty healthy patients were randomly assigned to one of four groups, each of which was anesthetized with 1% end-tidal isoflurane and 67% nitrous oxide in oxygen after endotracheal intubation. ⋯ On the other hand, all of 20 patients in the control-epinephrine and the clonidine-epinephrine groups exhibited positive SBP responses (SBP increment ≥15 mmHg). Therefore, based on the SBP criterion, sensitivities, specificities, and positive and negative predictive values were all found to be 100% regardless of the presence of clonidine. We conclude that oral clonidine 5μg·kg(-1) premedication alters neither (a) hemodynamic responses to the intravenously administered epidural test dose containing 15 μg epinephrine, nor (b) the efficacy for detecting intravascular injection based on either criterion in adult patients under stable isoflurane anesthesia.