Comparative study of different epidural infusion sets at maximum speeds for labor analgesia

The higher injection pressure obtained with epidural boluses give greater anaesthetic spread, and therefore better sensory block. Therefore, it stands to reason that anaesthetic administered at greater injection pressure and a higher flow rate would spread to a higher sensory level.

Our aim was to compare the sensory level reached with the high flow. and standard flow set at maximum rates.

We included 73 primiparous women who requested epidural analgesia for labour using programmed intermittent epidural boluses of 0.1% ropivacaine at a flow rate of 10ml/h and 2 ug/ml fentanyl plus patient-controlled epidural analgesia. The boluses were administered with a standard (250ml/h) or high-flow (500ml/h) infusion set, according to the usual clinical practice of each anaesthesiologist. The primary objective was to evaluate the sensory level reached. Secondary objectives were pain on a visual analogue scale, motor block measured on the modified Bromage scale, and anaesthesia consumption in terms of rescue analgesia (patient-controlled epidural analgesia) and anaesthesiologist-administered boluses.

The median maximum sensory level reached was T9 in the high flow group and T7 in the standard flow group; this difference was statistically significant (p=.0002). There were no significant differences in visual analogue scale, Bromage or rescue analgesia between groups.

Our results show that the high flow set does not offer benefits. The use of such sets need to be evaluated due to their higher cost.