Quality of Labour Epidural Analgesia With Intrathecal Morphine as a Component of Combined Spinal Epidural

The addition of morphine to a combination of bupivacaine and lipophilic opioids (fentanyl) for the spinal component of CSE for labor analgesia has been shown to increase the duration of analgesia. A meta-analysis by Al-Kazwini and coworkers suggests a possible beneficial prolonging effect of adding morphine to spinal analgesia, however, the authors concluded that more adequately powered randomized controlled trials (RCTs) are required to determine the benefits and harms of intrathecal morphine (ITM). This prolonged duration of action of ITM may reduce the need for frequent top-ups, which could alleviate nursing and anesthesiologist workload and enhance maternal satisfaction. An RCT conducted by Vasudevan and coworkers has concluded that the addition of 100 mcg ITM along with bupivacaine and fentanyl reduced the incidence of breakthrough pain in labor. Another dose-finding study comparing 50 and 100 mcg of ITM as a component of CSE labor analgesia concluded that 100 mcg of ITM significantly lowers the local anesthetic consumption and shorter duration of the first stage of labor without any significant difference in adverse effects. The RCT by Vasudevan et al. had a small sample size, enrolled mixed parity patients, and utilized continuous infusion for labor analgesia maintenance. Hence, the investigators plan to conduct adequately powered RCT enrolling only primigravidae patients, which tend to have more prolonged labor than multiparous and programmed intermittent epidural bolus (PIEB) with patient-controlled epidural analgesia (PCEA) will be used, which is a more contemporary labor maintenance technique.