Transversus Abdominis Plane Block Versus Wound Infiltration for Analgesia After Cesarean Delivery: A Randomized Controlled Trial

The study will conduct at the obstetric department of ASWAN University Hospital in ASWAN, Egypt, from January 2018 to the end of January 2019. Eligible subjects were American Society of Anesthesiologists physical status I, II parturient with full-term singleton pregnancies undergoing elective cesarean delivery under spinal anesthesia.

Exclusion criteria were: <19 years of age or >40 years of age; height <150 cm, weight <60 kg, body mass index (BMI) >=40 kg/m2; contraindications to spinal anesthesia (increased intracranial pressure, coagulopathy, or local skin infection); history of recent opioid exposure; hypersensitivity to any of the drugs used in the study; significant cardiovascular, renal, or hepatic disease; and known fetal abnormalities.

The study subjects will randomly have assigned to 2 equal groups (infiltration and TAP groups) using a computer-generated table of random numbers. A single investigator assessed the patients for eligibility, obtained written informed consent, and recorded the baseline data for each participant during the preanesthetic interview on the day of delivery. Sequentially numbered, sealed opaque envelopes containing group allocation were opened by the primary investigator after administration of spinal anesthesia. Neither the study subjects nor the outcome assessors knew the study group. The patients were separated from the surgical field and the operators by a large opaque screen. The primary investigator, who had experience in TAP block, performed the TAP block and the Sam procedure after closure of the skin when the patients were still lying on the operating table. The local anesthetic wound infiltration was performed by the operating obstetrician. An obestetrician resident who was not involved in the study, will record the intraoperative data and prepare, as instructed by the primary investigator, the local anesthetic solution for the TAP block and wound infiltration. The outcome data (opioid consumption, , pain scores, level of sedation, side effects, and patient satisfaction) were recorded by a blinded investigator who visited the patient in the ward at 2, 4, 6, 12, and 24 hours postoperatively.

No premedication was administered. Standard monitors (noninvasive blood pressure, electrocardiography, and pulse oximetry) were applied, and spinal anesthesia was administered in the sitting position at the L3-L4 or L4-L5 interspace using a 27-gauge or 25-gauge spinal needle; 12.5 mg of hyperbaric bupivacaine (2.5 mL 0.5%) and 15 µg of fentanyl were intrathecally administered. Surgery started after attaining an upper sensory level of T6 or higher, tested with pinprick. If the upper sensory level was below T6 after 20 minutes, this was considered a failed spinal, and the patient would have been excluded from the study. Lower segment cesarean delivery was performed using the Pfannenstiel incision, and exteriorization of the uterus was done in all cases. The upper sensory level was assessed using pinprick 30 minutes after intrathecal injection and recorded. If the patient complained of abdominal pain or discomfort after the start of surgery, 2 mg of intravenous (IV) midazolam was administered. If pain or discomfort persisted after midazolam administration, IV fentanyl and Propofol were administered as appropriate, and the patient was excluded from the study.

In the infiltration group, at the end of surgery, 30 mL of bupivacaine 0.25% was injected subcutaneously in the surgical wound (15 mL in each of the upper and lower sides) by the obstetrician before skin closure. Sam procedure was performed by the primary investigator after completion of surgery by pressing a covered spinal needle on both sides of the patient's abdomen.