This study evaluated the efficacy of a T-wave change after the IV administration of low dose epinephrine containing the test dose during spinal anesthesia.

Eighty healthy adults undergoing spinal anesthesia were enrolled in this study. The subjects were divided randomly into the following 4 groups: Group S (n = 20) received 3 ml of normal saline, group L (n = 20) received 3 ml of 1.0% lidocaine, group E5 received 3 ml of 1.0% lidocaine with epinephrine 5 µg, and group E10 received 3 ml of 1.0% lidocaine with epinephrine 10 µg. The heart rate (HR) and T-wave amplitude were measured with an electrocardiogram and systolic blood pressure (SBP) using a non-invasive method. Positive responses were defined as an increase in HR ≥ 20 bpm or SBP ≥ 15 mmHg, or a decrease in the T-wave amplitude ≥ 25%.

The sensitivity (Ss), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) of the HR increases were 80%, 100%, 100%, and 83%, respectively, in groups E5 and E10. For the SBP increases, the Ss, Sp, PPV, and NPV were respectively, 55%, 100%, 100%, and 70% in group E5, and 80%, 100%, 100%, and 83% in group E10. For the ≥ 25% decrease in T-wave amplitude, Ss, Sp, PPV, and NPV were respectively, 100%, 90%, 91%, and 100% in group E5, and 95%, 90%, 90%, and 95% in group E10.

These results suggest that a change in the T-wave amplitude is useful for detecting the unintentional IV administration of low dose epinephrine during CSEA.