Transversus Abdominis Plane Block Versus Wound Infiltration for Analgesia After Cesarean Delivery
Condition: Cesarean Section
Study type: Interventional

Summary: 
      Adequate pain control after cesarean delivery is a major concern both for parturient and for
      obstetric anesthesiologists, and it usually comprises a combination of systemic and regional
      techniques.The transversus abdominis plane (TAP) block, affecting the nerves supplying the
      anterior abdominal wall, is a recently introduced, promising regional analgesic technique for
      a variety of abdominal and pelvic surgeries including cesarean delivery.(2,3) Infiltration of
      local anesthetic into the surgical wound (either as a single shot or using indwelling
      catheters) has long been used for postoperative analgesia.

      Both the TAP block (4-6) and wound infiltration is superior to placebo; however, it is
      unknown which of them provides better analgesia after cesarean delivery because of a scarcity
      of randomized clinical trials. Only 2 studies compared the TAP block with wound infiltration
      after cesarean delivery with conflicting results, and another study compared it with
      continuous wound infusion and was prematurely terminated.

      This study aimed to compare bilateral TAP block with single-shot local anesthetic wound
      infiltration for analgesia after cesarean delivery performed under spinal anesthesia. We
      hypothesized that the TAP block would decrease postoperative cumulative opioid consumption at
      24 hours
    

Detailed description: 
      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.

      In the TAP group, after completion of surgery, 20 mL of bupivacaine 0.25% was injected under
      direct visualization in the plane between the transversus abdominis muscle and the fascia
      deep to the internal oblique muscle on each side.

      Duration of surgery (time from the start of skin incision to the end of skin closure) was
      recorded.The study subjects received postoperative standard analgesia according to their pain
      scale At 2, 4, 6, 12, and 24 hours postoperatively, the severity of pain at rest and on
      movement (hip flexion and coughing) was assessed using an 11-point numerical rating scale (0
      = no pain and 10 = the worst possible pain). Patient satisfaction from postoperative
      analgesia was assessed at 24 hours postoperatively using a 5-point scale (1 = very
      unsatisfied, 2 = unsatisfied, 3 = fair, 4 = satisfied, and 5 = very satisfied(.

      The primary outcome was cumulative opiod consumption at 24 hours. Secondary outcomes were the
      time to the first postoperative fentanyl dose, cumulative fentanyl consumption at 2, 4, 6,
      and 12 hours, pain scores at rest and on movement at 2, 4, 6, 12, and 24 hours, the deepest
      level of sedation, the incidence of side effects (nausea and vomiting and pruritis), and
      patient satisfaction.

      Statistically analysis:

      Data were entered and statistically analyzed using the Statistical Package for Social
      Sciences (SPSS) version 16. Qualitative data were described as numbers and percentages.
      Chi-square test and Monte Carlo test were used for comparison between groups, as appropriate.
      Quantitative data were described as means (SD) or medians, as appropriate. They were tested
      for normality by Kolmogorov-Smirnov test. In the normally distributed variables, one-way
      ANOVA test with LSD post-hoc multiple comparisons was used for comparison between groups. In
      the non-normally distributed variables, Kruskal-Wallis test was used for comparison between
      groups. -Odds ratios and their 95% confidence interval were calculated. "p-value ≤0.05" was
      considered to be statistically significant.
    

Intervention name(s): 20 mL of bupivacaine 0.25%
Intervention type(s): Drug
Intervention description(s): 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.
In the TAP group, after completion of surgery, 20 mL of bupivacaine 0.25% was injected under direct visualization in the plane between the transversus abdominis muscle and the fascia deep to the internal oblique muscle on each side.
Other intervention name(s): 30 mL of bupivacaine 0.25%
Intervention MeSH terms: Bupivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Randomized Controlled Trial
Masking: Single (Participant)
Primary purpose: Prevention
Keywords: Transversus Abdominis Plane Block; Cesarean Delivery