Transcutaneous electrical nerve stimulation does not augment epidural labor analgesia.

STUDY OBJECTIVE

To evaluate whether transcutaneous electrical nerve stimulation (TENS) can increase the quality and duration of an initiation dose of bupivacaine used for the establishment of epidural labor analgesia.

DESIGN

Randomized, double-blind study.

SETTING

Tertiary-care academic medical center.

PATIENTS

40 ASA physical status I and II parturients in early, active spontaneous labor with a singleton, vertex term fetus, and requesting analgesia.

INTERVENTIONS

A standardized epidural technique with either an active or inactive TENS unit was performed. Before epidural placement, TENS intensity thresholds were determined with electrodes placed over the paraspinus muscles at T(10)-L(1), and S(2)-S(4); TENS settings for mode, cycle, and pulse width were standardized.

MEASUREMENTS

Data were collected at timed intervals on pain as measured by visual analog scale (VAS), sensory level (pinprick), motor blockade (Bromage score), cervical dilation, and duration of analgesia.

MAIN RESULTS

The duration of analgesia produced by the initial dose of epidural bupivacaine did not differ between groups (TENS turned off 82.3 +/- 26 [mean +/- SD] vs. TENS activated 80.7 +/- 40 min, p = 0.88). Kaplan-Meier survival analysis and Mantel-Cox log rank analysis showed no difference between the two treatments (p = 0.75). No difference in the quality of analgesia was observed between the two groups.

CONCLUSIONS

In healthy laboring parturients, the application of a TENS unit did not alter the quality or duration of an initiation dose of bupivacaine utilized for the establishment of epidural labor analgesia.