Comparison of three different loading doses to establish epidural analgesia in labour

Ropivacaine 1 mg/ml, plus fentanyl 2 microg/ml for epidural analgesia during labour. Is mode of administration important?

BACKGROUND

Patient-controlled epidural analgesia (PCEA) with a moderate to high concentration of bupivacaine in obstetrics has been shown to give comparable analgesia and even higher level of satisfaction compared to continuous epidural infusion. We hypothesised that the use of a very low concentration technique (ropivacaine/fentanyl) might result in excessive dosing in the PCEA group, more motor blockade and a negative impact on spontaneous delivery rate.

METHODS

We conducted a randomised, double-blind study of 60 nulliparous women at term comparing low concentration ropivacaine/fentanyl administered in either patient-controlled or fixed continuous infusion mode. Parturients with known predictors of painful deliveries, i.e. breech presentation, primary induction of labour, were not included. Deliveries within 90 min from the start of epidural analgesia were omitted from the evaluation.

RESULTS

We found that both groups required a mean of 12 ml/h low concentration mixture (loading and midwife rescue boluses included). There was no difference between groups with respect to spontaneous delivery rate (71%). This low concentration technique resulted in haemodynamic stability without crystalloid preloading, infusion or vasopressor use. Motor blockade of clinical importance was not detected in any patient.

CONCLUSION

We conclude that epidural use of ropivacaine 1 mg/ml+fentanyl 2 microg/ml provides effective analgesia with equal volume requirements irrespective of administration mode, with a high spontaneous delivery rate. Choice of PCEA or CEI (continuous epidural infusion) should be directed by other considerations, most importantly compliance of midwife and possible reduction in workload for anaesthesiology staff.

Ambulatory labor epidural analgesia: bupivacaine versus ropivacaine

Dilute concentrations of bupivacaine combined with fentanyl have recently been used to initiate labor epidural analgesia in an attempt to balance adequate analgesia and minimal maternal motor blockade. Similar concentrations of ropivacaine have not been evaluated. This prospective, randomized, double-blinded study was designed to compare the efficacy of 20 mL of either 0.08% bupivacaine plus 2 microg/mL fentanyl or 0.08% ropivacaine plus 2 microg/mL fentanyl to initiate ambulatory labor epidural analgesia. Forty nulliparous women in early (</=5 cm) established labor received either 20 mL of 0.08% bupivacaine plus 2 microg/mL fentanyl (BF) or 0.08% ropivacaine plus 2 microg/mL fentanyl (RF) to initiate epidural analgesia. One woman (BF) required supplemental analgesia, and two (one BF and one RF) had visual analog scale scores > 0 but < 20 at 20 min. The time (mean +/- SD) to visual analog scale score = 0 was BF (n = 18): 12.0 +/- 4.5 min and RF (n = 19): 12.4 +/- 4.0 min (P > 0.05). Spontaneous micturition was observed in 65% (13 of 20) BF compared with 100% (20 of 20) RF (P < 0.01), and ambulation was demonstrated in 75% (15 of 20) BF compared with 100% (20 of 20) RF (P < 0.03). The incidence of forceps delivery was 35% (7 of 20) BF compared with 10% (2 of 20) RF (P < 0.04). The results of this study indicate that dilute ropivacaine combined with fentanyl effectively initiates epidural analgesia while concurrently preserving maternal ability to void and ambulate.

IMPLICATIONS

As compared with a similar dilute concentration of bupivacaine, 20 mL of dilute (0.08%) ropivacaine combined with fentanyl (2 microg/mL) effectively initiates epidural analgesia in nulliparous women in early, established labor while preserving their ability to micturate and ambulate. Of importance, it appears that a true ambulatory epidural analgesic for women in labor is now possible.