Clonidine versus sufentanil as an adjuvant to ropivacaine in patient-controlled epidural labour analgesia: A randomised double-blind trial.

BACKGROUND: Adjuvants to local anaesthetics for epidural labour analgesia are useful if they reduce side-effects or personnel requirements. Epidural clonidine improves analgesia and provides a significant local anaesthetic-sparing effect.

OBJECTIVE: To compare the number of rescue doses administered by the anaesthesiologist when clonidine or sufentanil is added to epidural ropivacaine.

DESIGN: A randomised double-blind trial.

SETTING: Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium, from June 2009 to June 2010.

PATIENTS: One hundred and ninety-five women in labour.

INTERVENTION: Epidural analgesia initiated with 10 ml ropivacaine 0.1%, women randomised to receive patient-controlled epidural analgesia (5 ml demand bolus, 15 min lockout) with ropivacaine 0.1% and sufentanil 0.25 μg ml⁻¹ (RS group; n = 65), or ropivacaine 0.1% and clonidine 1.5 μg ml⁻¹ (RC1.5 group; n = 65) or ropivacaine 0.1% and clonidine 3 μg ml⁻¹ (RC3 group; n = 65). Rescue analgesia was available as needed – 10 ml ropivacaine 0.1% (numerical rating scale <6/10) or ropivacaine 0.2% (numerical rating scale ≥6/10).

MAIN OUTCOME: Comparison of the total number of rescue doses.

RESULTS: The total number of rescue doses was similar among the groups [median (interquartile range): 1 (0 to 1) in the RC1.5 group, 1 (1 to 2) in the RC3 group and 2 (1 to 2) in the RS group; overall P = 0.056]. However, fewer patients in both the RC1.5 and RC3 groups needed two or more rescue doses (25 and 29% versus 52% in the RS group, P = 0.01). The rate of instrumental delivery was higher in both clonidine groups (13 and 12% versus 0%, P = 0.03). Nausea was significantly less frequent in both the clonidine groups. Satisfaction scores, total ropivacaine consumption, maternal sedation, and hypotension and neonatal outcomes were similar among the groups.

CONCLUSION: Compared with sufentanil 0.25 μg ml⁻¹, addition of clonidine (1.5 to 3 μg ml⁻¹) to patient-controlled epidural analgesia with ropivacaine 0.1% provided similar labour analgesia and a similar need for anaesthesiologist-administered rescue doses. Clonidine 3 μg ml⁻¹ did not offer any advantage over clonidine 1.5 μg ml⁻¹. The instrumentation rate was higher in both the clonidine groups.