Background: In recent years, the number of cesarean deliveries is on the rise. Although intrathecal morphine (ITM) can relieve pain and is widely applied in cesarean deliveries, it is also associated with many side effects. As a new analgesic technology, transversus abdominis plane (TAP) block has also begun to play a certain role after cesarean delivery, with fewer adverse effects. This article mainly compares the analgesic and adverse effect of ITM and TAP block in cesarean delivery.
Methods: We systematically searched PubMed, Cochrane library, Embase and Web of Science, for randomized controlled trials before October 5, 2020 to compare ITM and TAP block. Our main result is the pain score at rest 24 hours after cesarean delivery, and the secondary result is the pain score at movement 24 hours after operation, postoperative nausea and vomiting (PONV), itching, and morphine consumption. We conducted a subgroup analysis based on economic development.
Result: Six articles with 563 sample sizes were included. The results showed there was no significant difference between ITM and TAP block in the pain score at rest 24 hours after surgery (95% CI: -1.33 to 0.40; P=0.29). After subgroup analysis based on economic development, Parturients in the ITM group have lower rest pain score than those in the TAP group (95% CI: -1.27 to -0.28; P=0.002) in the developed area. There was no significant difference in the 24h moving pain score (95% CI:-1.47 to 0.29;P=0.19)and incidence of pruritus (95% CI:0.87 to 8.85;P=0.08). The ITM group showed less morphine consumption when compared with the TAP group (95% CI:-13.12 to -2.95;P=0.002). The incidence of PONV was lower in the TAP group as compared to the ITM group (95% CI:1.92 to 4.87; P<0.00001).
Conclusion: We found that Parturients in the ITM and TAP block groups had similar analgesic effects. However, after subgroup analysis, in developed countries, Parturients in the ITM group has better analgesic effects than those in the TAP block group with less morphine consumption. Differently, TAP block had low side effects such as nausea, vomiting. Therefore, if patients cannot use ITM for analgesia after cesarean delivery, or patients have high risk of PONV, then TAP is still a valuable analgesia option.
Registration number: Registered on Prospero with the registration number of CRD42020210135