This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Bernard, J.-M. Articles by Frouin, J. Search for Related Content PubMed PubMed Citation Articles by Bernard, J.-M. Articles by Frouin, J. Related Collections Obstetrics Regional Anesthesia Pain Pharmacology

---

OBSTETRIC ANESTHESIA

Ropivacaine and Fentanyl Concentrations in Patient-Controlled Epidural Analgesia During Labor: A Volume-Range Study

From the Département d’Anesthésie-Réanimation, Polyclinique Jean-Villar, Bruges-Bordeaux, France

Address correspondence and reprint requests to Dr. Jean-Marc Bernard, Département d’Anesthésie-Réanimation, Polyclinique Jean-Villar, BP 61, F-33520 Bruges-Bordeaux, France. Address email to jmbmdphd{at}club-Internet.fr

We enrolled nulliparous women in induced labor in a randomized study to determine whether increasing the concentration of the solution used in a patient-controlled epidural analgesia (PCEA) device was required as labor progressed. Patients were assigned to 6 groups (n = 25 in each group), receiving ropivacaine/fentanyl in concentrations of either 0.1%/0.5 µg/mL or 0.2%/1 µg/mL via a PCEA pump. Three groups received boluses of 12, 16, or 20 mL dilute solution in early labor (uterine contractions every 3 min and 4-cm cervical dilation) then 6, 8, and 10 mL concentrated solution in late labor. Three other groups received boluses of 12, 16, or 20 mL dilute solution during both periods. The lockout interval was 25 min. The primary outcome was time until the first request for staff-administered analgesia supplement. Hourly assessments included pain scores on a visual analog scale (VAS) graded from 0 to 10, satisfaction scores, arterial blood pressure, motor block intensity, and the upper sensory level of epidural anesthesia. Patients, midwives, and the observer were unaware of study solutions and PCEA settings. The maximum pain score was defined as the highest score experienced by each patient during each period. Duration of analgesia was defined as the time from the start of each period to the first injection of rescue analgesia and was compared using a survival analysis. There were no differences among the groups with regard to demographic and obstetric variables, arterial blood pressure, motor block intensity, upper sensory level, or satisfaction scores. At least 75% of the women rated their satisfaction as either good or excellent during each period. During late labor, the maximum pain score was lower in the group receiving 20 mL dilute solution compared with the group receiving 6 mL concentrated solution. Maximum pain score was not significantly different between 20 mL dilute solution and 10 mL concentrated solution (difference between VAS values = -0.4; 95% confidence limits, -1.599 and 0.799; P = 0.5055). During late labor, the duration of analgesia was longer in groups receiving 20 mL dilute solution (99 ± 4 min) (mean ± SD) than in those receiving 12 mL (77 ± 30 min) and 16 mL (80 ± 23 min). Duration of analgesia did not differ between groups receiving 20 mL and 10 mL (92 ± 23 min) or between groups receiving 12 mL and 6 mL (78 ± 30 min) of each respective solution. Duration of analgesia was longer in the groups receiving 8 mL concentrated solution (94 ± 16 min) than in those receiving 16 mL dilute solution. We concluded that 0.1%/0.5 µg/mL ropivacaine/fentanyl was effective throughout labor when 20 mL was injected with each PCEA demand. With 16 mg ropivacaine and 8 µg fentanyl, the duration of analgesia was prolonged by doubling the concentration when labor became active. When 12 mg ropivacaine and 6 µg fentanyl were injected at each demand, analgesia was less satisfactory and doubling the concentration was not clinically effective. These results suggest that the effectiveness of PCEA is dependent on drug mass rather than the volume or concentration administered with each successful pump demand.

IMPLICATIONS: There is no clinical reason for increasing the concentration of the patient-controlled epidural analgesia (PCEA) solution when labor becomes active provided that an effective dose is already being administered with each demand. The quality of PCEA depends on the drug mass given with each demand rather than the concentration of the pump solution.

This article has been cited by other articles:

				S. H. Halpern and B. Carvalho Patient-Controlled Epidural Analgesia for Labor Anesth. Analg., March 1, 2009; 108(3): 921 - 928. [Abstract] [Full Text] [PDF]