The addition of hydromorphone to epidural fentanyl does not affect analgesia in early labour

PURPOSE: Epidural fentanyl after a lidocaine and epinephrine test dose, provides adequate analgesia and allows for ambulation during early labour. The current study was designed to determine the influence of hydromorphone added to an epidural fentanyl bolus (e.g., whether there is an increase in duration of analgesia). METHODS: Forty-four labouring primigravid women, at less than 5 cm cervical dilation, who requested epidural analgesia were enrolled in this randomized, double-blind study. After a 3 mL test dose of lidocaine with epinephrine, patients received fentanyl 100 microgram (in 10 mL volume). They randomly received the fentanyl with either saline or hydromorphone (300 microgram). After administration of the initial analgesic, pain scores and side effects were recorded for each patient at ten, 20, and 30 min, and every 30 min thereafter, by an observer blinded to the technique used. RESULTS: The patients were taller in the hydromorphone group (P < 0.04). There were no other demographic differences between the two groups. The mean duration prior to re-dose was not significantly different in the group that received hydromorphone (135 +/- 52 min) compared to the control group (145 +/- 46 min). Side effects were similar between the two groups. No patient in either group experienced any detectable motor block. CONCLUSION: In early labouring patients, the addition of hydromorphone (300 microgram) to epidural fentanyl (100 microgram after a lidocaine and epinephrine test dose) neither prolongs the duration of analgesia nor affects the ability to ambulate, and cannot be recommended according to the current study.