According to a randomized controlled clinical trial, single-orifice catheters used for programmed intermittent epidural bolus at 480 mL/hour for epidural labor analgesia have enhanced analgesic efficiency when compared to multiorifice catheters. Researchers did a comparative assessment of analgesic outcomes of wire-reinforced catheters under 480 mL/hour delivery rate with programmed intermittent use of epidural bolus.

Overall, 182 healthy and nulliparous women who were expecting a singleton pregnancy, had a cervical dilatation of 2 to 5 cm, and needed neuraxial analgesia were randomly assigned to receive single- or multiorifice catheters. Sufentanil at a concentration of 0.3 mg/mL and 0.1% Ropivacaine were used to commence and sustain epidural analgesia. Following the test dosage, a 10 mL programmed intermittent epidural bolus volume was given every 45 minutes at a rate of 480 mL/hour. The proportion of parturients in the two arms who had suitable analgesia 20 minutes following the initial bolus was the key endpoint.

In comparison with the multiorifice catheters, the use of single-orifice catheters was linked to an increased percentage of parturients with satisfactory analgesia (71.8% vs 56.0%) and more common S2 sensory blockade (37.6% vs 22.6%) 20 min following block commencement. With multiorifice and single-orifice catheters, the median time (IQR) to sufficient analgesia was 20 (10-47) min and 12 (8-30) min, respectively. In comparison to parturients using single-orifice catheters, those getting multiorifice catheters consumed more Ropivacaine on average per hour (15.3 (13.3-17.0) mg/hour vs. 13.3 (13.3-15.4) mg/hour).