Epidural clonidine added to a bupivacaine infusion increases analgesic duration in labor without adverse maternal or fetal effects.

PURPOSE

Many obstetric patients receiving epidural analgesia are encouraged to ambulate. This current study was designed to determine the potential for maximizing the time to first epidural supplement when adding clonidine to a 0.625 mg.ml(-1) bupivacaine continuous epidural infusion following epidural fentanyl bolus in early labor for patients allowed to ambulate. Maternal and fetal effects secondary to clonidine were also evaluated.

METHODS

Sixty-eight laboring primigravid women received a 3-ml epidural test dose of lidocaine with epinephrine, followed by a fentanyl 100-microg bolus (in a 10 ml-volume). The patients then received a 0.625 mg.ml(-1) bupivacaine continuous epidural infusion, either with or without clonidine (5 microg.ml(-1)), at a rate of 10 ml.h(-1). Pain scores and side effects were recorded for each patient.

RESULTS

The overall quality of analgesia was similar in both groups. The mean duration prior to request for additional analgesia was significantly longer in the clonidine group (269 +/- 160 min), compared to the control group (164 +/- 64 min). No patient in either group experienced any detectable motor block; one patient (clonidine group) complained of mild thigh numbness and was not allowed to ambulate. While mean blood pressure was approximately 6 mmHg lower in the clonidine group at 1, 1.5, and 3.5 h, this was not clinically significant. No adverse effects on maternal heart rate or fetal heart rate were noted.

CONCLUSION

In early laboring patients, addition of clonidine prolongs the analgesia duration of a 0.625 mg.ml(-1) bupivacaine continuous epidural infusion following 100 microg epidural fentanyl (after a lidocaine-epinephrine test dose) without a clinically significant increase in side effects.