In Reply:- We thank Drs. Joos and Van Steenberge for their thoughtful reading of our case report and congratulate them on their continued dedication to the field of obstetric anesthesia and their continued refinements to make it more safe and effective. They raise several important tenets of labor analgesia and uncover some important uncertainties. First, one clearly should use the lowest effective dose of intraspinal agent. As they nicely discuss, there has been a steady decrease in the concentration and dose of epidural bupivacaine used in obstetric analgesia, and although many consider bupivacaine, 0.125%, plus opioid an overdose, we agree with our European colleagues that lower concentrations are not routinely effective.

The lowest effective dose of intrathecal sufentanil alone or with bupivacaine is not known. Although initial studies used 10 - 15 [micro sign]g sufentanil, lower doses (5 - 7.5 [micro sign]g) are being used. Few dose - response data exist, and those that have been recently published show a very flat dose-response, perhaps reflecting a wide variability in response as labor progresses.

Whereas we are clearly in favor of combining [small alpha, Greek]-2-adrenergic agonists, local anesthetics, and opioids for spinal analgesia, there are virtually no systematic data that show the “best ratio” of epinephrine, bupivacaine, and sufentanil for labor analgesia. We use sufentanil (7.5 [micro sign]g) plus bupivacaine (2.5 mg) as a combination that has been described and that produces a reasonable period of analgesia in early and late labor. Whether lower doses would be equally effective for similar durations of time is not known. To suggest that the concoction used at our colleagues' institutions represents the “required effective but also safe dosage” is unsubstantiated, their audit not withstanding.

We disagree that the dose administered in our case represents an overdose. Rather, we agree entirely with Drs. Joos and Van Steenberge that vigilance and refinements of dose are essential to safe and effective treatment of labor pain.

James C. Eisenach, M.D.

Robert D'Angelo, M.D.

Department of Anesthesia; Wake Forest University School of Medicine; Winston-Salem, North Carolina