Cardiovascular criteria for epidural test dosing in sevoflurane- and halothane-anesthetized children

This study was designed to determine the detectability of a simulated IV te st dose in children during administration of general anesthesia by using he art rate (HR), systolic blood pressure (SBP), and T wave criterion. Forty-t wo children (0.5-8 yr old) received an IV injection containing epinephrine 0.5 mu g/kg and another IV injection containing saline during either haloth ane or sevoflurane anesthesia administration at 1.0 minimum alveolar concen tration in nitrous oxide. A positive test response was defined as a change in T wave amplitude greater than or equal to 25%, SEP increase greater than or equal to 15 mm Hg, and HR increase greater than or equal to 10 bpm. By using the T wave, SEP, and HR criteria, a positive response rate to epineph rine was 100%, 95%, and 71%, respectively, during sevoflurane, and 90%, 71% , and 71%, respectively, during halothane anesthesia administration. These data suggest that the T wave criterion is superior to conventional hemodyna mic criteria, and that sevoflurane attenuates T wave and SEP responses less than halothane; however, chronotropic responses are similar to halothane. Implications: We found a greater reliability of the T wave criterion over c onventional hemodynamic criteria for detecting intravascular injection of a simulated epidural test dose. Sevoflurane may increase the likelihood of r ecognition of an accidental intravascular injection of epinephrine-containi ng solutions in clinical practice compared with halothane.