A comparison of Different Rates of Epidural Infusion Immediately Following Combined Spinal-Epidural Technique for Labor Analgesia
Abstract Number: 68
Abstract Type: Original Research
Background and Objectives
Combined spinal-epidural (CSE) analgesia in labor has gained wide popularity in obstetric anesthesia. Immediate initiation of epidural infusion (EI) allows to prolong initial analgesia and to reduce the incidence of breakthrough pain. However, there is no consensus among anesthesiologists as to the optimal initial rate of EI. We compared the clinical effects of three different rates of EI initiated immediately after the subarachnoid injection (SI) as part of CSE for labor analgesia.
After IRB approval, a total of 62 healthy women in labor with a cervical dilation of 3 to 6 cm were randomized to receive EI with 0.125 % Bupivicaine and 0.0002% Fentanyl at the rates of 5, 10 or 15 ml/hr as part of CSE. All patients received SI of Bupivicaine 2.5 mg and Fentanyl 4 mcg as induction of CSE. 10 minutes later, following negative aspiration test and negative epidural test dose consisting of 1.5 % Lidocaine with Epinephrine 1:200,000, EI was started at assigned initial rate. Clinically appropriate interventions were performed to maintain labor analgesia and hemodynamic stability and to avoid excessive motor block. Duration of initial analgesia, number of epidural-related calls (ERC), motor block, hemodynamic variables, side effects, and obstetrical outcomes were assessed and compared among groups.
There were no differences among the groups in pain score during the first 120 minutes. The duration of initial analgesia was the shortest in Rate 5 group; 60% of patients in this group requested additional analgesia (mean time from SI to additional analgesia 137.5 minutes) compared to 1 patient in Rate 10 group and no patients in Rate 15 group requesting additional analgesia (p<=0.0000). The mean number of ERC per patient was significantly higher (p<0.01) in the Rate 5 group (0.95) than in Rate 10 (0.19) and Rate 15 (0.29) groups. Motor block was significantly more frequent (p<0.001) in the Rate 15 group (in 62% of patients) compared to Rate 5 and 10 groups (10% and 29% of patients respectively). There were no significant differences in the incidence of hypotension that required treatment or in the incidence of cesarean section deliveries among the three groups. Other side effects profiles were the same among all groups.
Our results suggest that immediate initiation of EI following induction of CSE prolongs the duration of initial analgesia in all three groups, however, in Rate 5 group the need for additional analgesia and the frequency of ERC is much higher after 120 minutes. In Rate 15 group the incidence of motor block appears to be significantly higher. We conclude that the EI rate at 10 ml/hr provides satisfactory labor analgesia without excessive motor block and is associated with minimal frequency of ERC.
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