Intrathecal labor analgesia with bupivacaine and sufentanil: the effect of adding 2.25 microg epinephrine

Epinephrine, 25 microg and 200 microg, has been found to prolong the duration of intrathecal labor analgesia when added to an opioid. In our hospital we use the standard epidural mixture, prepared by the pharmacist, containing epinephrine 1:800,000; i.e., 1.25 microg/mL for both spinal and epidural labor analgesia. We wanted to evaluate whether such a low dose, depending on its effect on duration or quality of analgesia, should be maintained or deleted in future mixtures.

Forty-five term parturients were randomly assigned to receive 1.8 mL intrathecally of a mixture containing bupivacaine 0.125% and sufentanil 0.75 microg/mL with or without epinephrine 1.25 microg/mL. The quality and duration of analgesia, side effects, and obstetric/neonatal outcome were compared.

For both combinations, the onset until the first painless contraction was between 5 and 6 minutes. Most patients were pain free during the second uterine contraction. The duration of complete analgesia was 93.2 +/- 24.2 minutes in the epinephrine group and 79.3 +/- 18.1 minutes for patients not receiving epinephrine (P = .014). The quality of the block, bupivacaine consumption, side effects, and obstetric/neonatal outcome were not different between groups.

It was concluded that epinephrine in a dose as low as 2.25 microg significantly prolonged the duration of intrathecal analgesia of bupivacaine-sufentanil by 15 minutes. No other differences were noticed. Diluting the commercially available bupivacaine 0.5% with epinephrine 1:200,000 may avoid the need of freshly prepared epinephrine solutions.