Bolus of ropivacaine 0.1% versus 0.2% in obstetric epidural analgesia: a comparative prospective study

Abstract

Objective. Aim of this study is to compare the effect of the initial bolus: 10 ml of ropivacaine 0.2% (small volume, high concentration) and 20 ml of ropivacaine 0.1% (high volume, low concentration) during obstetric labor on the motor block, hemodynamic consequences, analgesia and parturient satisfaction.Patients and Methods. 56 parturients were included in this prospective, randomized, double-blind study. The parturients were randomized into two groups: group 1 receiving an initial bolus of 10ml of ropivacaine at 0.2% + 5 gamma of sufentanil and group 2 receiving an initial bolus of 20ml of ropivacaine at 0.2% + 5 gamma of sufentanil. The main endpoint was the evaluation of motor block.The secondary judgment criteria were: haemodynamic consequences, evaluation of obstetric analgesia by visual analogical scale, evaluation of the sensory level and satisfaction of the parturient.Results. The haemodynamic consequences were comparable for the 2 groups (p>0.05). The means of the VAS were similar (p>0.05). Motor block was similar in the 2 groups (14.81% for group 1 versus 6.89% for group 2 with p=0.57). A statistically significant difference was noted according to the sensory level which was higher in group 2 (p<0.05). The mean satisfaction was without significant difference (p=0.64). The adverse effects were similar in the two groups (p>0.05).Conclusions. Our study does not show a benefit of the use of a high volume low concentration compared to the use of small volume high concentration during the induction of the epidural.