INTRODUCTION<br />Pain has both sensory and emotional components that interact to produce an overall pain experience. According to International Association for Study of Pain (IASP) pain is defined as unpleasant emotional and sensory experience due to actual or potential tissue damage or described in terms of such damage [1].<br />Inability to control postoperative pain after Cesarean delivery (CD) can negatively affect ambulation, breastfeeding, and maternal bonding. Substantial pain is anticipated after cesarean delivery; therefore analgesic regimen should ensure effective and safe analgesia [2].<br />Specific benefits of minimizing opioid use may include the reduction of nausea and vomiting, ileus, urinary retention and hyperalgesia. So other techniques are needed to replace or reduce opioid and thus reducing their side effects [3].<br />There are numerous means of providing postoperative pain relief as part of multimodal analgesia. This includes intravenous or oral medications, epidural analgesia, wound infiltration or peripheral nerve blockade like TAP block [4].<br />Transversus Abdominis Plane block first described in 2001, a blind “double pop” Technique by which the needle passes the external oblique and internal oblique muscles used in clinical practice. The subcostal nerves that branch at the level of the mid-axillary line are blocked prior to their branching anteriorly and superficially to supply the abdominal wall. This has been shown to be an effective analgesic adjunct for lower abdominal surgeries [5,6].<br />Wound infiltration with local anesthetics has been investigated as a potentially useful and easy method in reducing the consumption of opioids and decrease opioid- related side-effects this is a part of multimodal analgesic approach this simple safe, low invasion and low cost technique commonly performed by surgeon [7,8].<br />Wound site infiltration and TAP block have opioid sparing analgesics effects but their relative efficacy is not well established.<br />The aim of this study is to compare the effectiveness of bilateral US guided TAP block vs. wound site infiltration for cesarean delivery under general anesthesia [9].<br /> <br /><br /><br /> <br />Aim of the work<br />The aim of the study is to compare analgesic effectiveness of bilateral US guided Transversus Abdominis Plane block (TAP) vs. single-shot local anesthetic Wound site Infiltration (WI) after cesarean delivery under general anesthesia.<br />PATIENTS AND METHODS<br />After ethical committee approval and informed consent from the patients, the present randomized controlled trial was conducted at Ain Shams University hospitals during the period from January to June 2021 on 195 cases with 3 groups 65 in each group TAP group, infiltration group and control group.<br />Study population Inclusion criteria:<br />• Patients undergoing elective cesarean section under<br />general anesthesia<br />• Pfannenstiel skin incision<br />• Age between ≥ 18 and ≤ 40 years old<br />• BMI between 18 and 35 kg/m2<br />Exclusion criteria:<br />• Patient refusal<br />• BMI <18 kg/m2 or >35 (require different dose of analgesia)<br />• Height <150 or >180 cm (require different dose of analgesia)<br />• Patients with any neurological deficit due to neuropathy and pain score affection<br />• Patients with bleeding disorders which may lead to hematoma<br />• HTN (Vasculopathy which can lead to hematoma)<br />• Cardiac disease (Vasculopathy on anticoagulant which can lead to hematoma)<br />• DM (decrease systemic and local immunity which can lead to abscess at injection site and due to neuropathy and pain score affection)<br />• Liver disease (defective clotting factors)<br />• A history of relevant drug allergy or hypersensitivity to any of the drugs used in the study due to impair of proper follow up of pain postoperative<br />• History of recent opioid exposure due to affection on pain score<br />• Local skin infection due to abscess formation<br />• Obstetric complications e.g. placenta previa and rupture uterus due to extensive tissue damage and <br /> <br />Randomization and allocation concealment<br />The study subjects were randomly assigned to 3 equal groups TAP group, infiltration group and control group using a computer-generated table of random numbers. A single investigator assessed the patients for eligibility, obtained written informed consent, and records the baseline data for each participant before delivery. Sequentially numbered, sealed opaque envelopes containing group allocation will be opened by the primary investigator after administration of general anesthesia. Neither the study subjects nor the outcome assessors knew the study group.<br />Ethical considerations<br />The study will be performed after approval of Research ethical committee, Faculty of medicine, Ain shams university and written informed consent from the patient. The study protocol will be explained to the patients after taking their consent to the type of anesthesia and surgical procedure.<br />Study tools<br />Spinal needle 22 g with injection lines.<br />Portable Ultrasound unit, Mindray DP-20linear probe (high frequency 10-12 MHz).<br />Study procedure<br />The Anaesthesilogist is senior staff trained on such procedure.<br />Pre-operative settingsl<br />• The study subjects will randomly assigned to 3 equal groups (TAP group, infiltration group and narcotics only group) using a computer-generated table of random numbers. A single investigator will assess the patients for eligibility, obtained written informed consent, and record the baseline data for each participant before delivery. Sequentially numbered, sealed opaque envelopes containing group allocation will be opened by the primary investigator after administration of general anesthesia. Neither the study subjects nor the outcome assessors knew the study group.<br />• Routine preoperative investigations will be done to all patients including laboratory investigations as (complete blood picture, liver function tests, prothrombin time and partial thromboplastin time).<br />• Demographic data as age, weight, will be recorded.<br />All mothers who scheduled for elective cesarean delivery who fulfilled inclusion criteria and volunteer are assessed by:<br />• Postoperative pain by visual analogue Scale (VAS)<br /> <br />Sabaa HA, et al. – The efficacy of ultrasound guided transversus abdominis plane (TAP) block vs. local wound infiltration for post-operative analgesia after cesarean section under general anesthesia: A randomized controlled double-blinded clinical<br />trial...<br /><br /> <br />pain score on arrival in the post-labor ward at 1, 2, 4, 6, 12, and 24 hours postoperatively.<br />• The duration of block (defined as the interval between performing the block and the time of the first request for analgesia) and total pethidine consumption were recorded in the 24 hours after surgery.<br />• The level of patient satisfaction was measured numerically by a Likert scale ranging from one to five, 1: “not satisfied at all” 2: “slightly satisfied” 3: “moderately satisfied” 4: “very satisfied” and 5: “highly satisfied”. Any adverse effects or complications will be recorded.<br />• Wide bore venous access will be secured by 18 G intravenous canula.<br />• The procedure is done in the operating rooms (OR) under complete aseptic technique with prophylactic antibiotics (e.g. 2 gm ceftriaxone).<br />Intra-operative settings:<br />• The patient will be monitored during the procedure using pulse oximetry, non-invasive blood pressure & ECG and capnography.<br />• Patients receive General anesthesia induction by propofol (2 mg/kg), Rocuronium(0.5 mg/kg) for rapid sequence intubation& Fentanyl (1 mcg/kg).<br />• Maintenance with rocuronium & isoflurane 1.2%.<br />Equipment’s that will be used for each patient are:<br />• Sterile towels, sponges, 4-inch gauze packs and povidone iodine 10% for sterilization.<br />• Sterile gloves, marking pen, 18-gauge cannula and 10-ml syringes containing drugs for administration of the procedure. Ultrasound device with Linear probe with high frequency (6 -13 MHz) will be used in imaging of patient.<br />Drugs that will be used in our study are:<br />• A 20 ml vial of 0.5% Bupivacaine HCl, pethidine IV (50-150 mg).<br />• Lower segment cesarean section will be performed using the Pfannenstiel incision.<br />• An anesthesiology resident will administer the general anesthesia, will record the intraoperative data (the duration of surgery), and prepared, as instructed by the primary investigator, the local anesthetic solution for the TAP block and wound infiltration. The outcome data (pethidine consumption, time to the first pethidine dose, pain scores level, side effects, and patient satisfaction) will be recorded by a blind investigator who will visited the patient in the ward at 1, 2, 4, 6, 12, and<br />24 hours postoperatively.<br />Group A: TAP group formed of 65 patients<br />• After completion of LSCS and skin closure and while the patient is still on the operating table U/S guided TAP block will be done using the following procedure:<br />• After preparing the skin with antiseptic solution, a linear high frequency ultrasound probe (Superficial probe of mindray DP-20) will be placed transversely on the anterolateral abdominal wall between the iliac crest and the costal margin. Under US guidance, the three layers of muscles -external oblique, the internal oblique, and the transversus abdominis will be identified. A Spinal needle 22 g attached with flexible tubing to a syringe filled with saline will be used to perform the block. The needle will be then introduced through the skin anteriorly in the plane of the ultrasound beam and advanced into the fascial plane between the internal oblique and transversus abdominis muscles with its tip lying in the mid axillary line. To assist with identifying these structures, the probe will be moved anteriorly to the rectus sheath and the fascial planes followed laterally. The final position of the probe will to be no further anterior than the anterior axillary line. If satisfactory views are not obtained, the TAP block will not be performed. Hydro dissection with saline (2-5 ml) will be used to separate the fascial layers. After aspiration to exclude inadvertent vascular puncture, a test dose of 1-2 ml of the drug will be injected to confirm needle placement. After a negative test dose, 20 ml of the 0.25% bupivacaine will be injected while closely observing for signs of toxicity e.g. CVS toxicity which may be in form of early features e.g. hypertension, tachycardia and ventricular arrhythmia or may be in form of late features e.g. hypotension, bradycardia, heart block and decreased contractility and other toxic signs<br />e.g. tinnitus, perioral numbness, metallic taste in mouth, slurring of speech and mental status changes). TAP block will be performed in a similar fashion on the opposite side.<br />Group B: The Infiltration Group formed of 65 patients<br />• This group will B wills provided with single-shot local anesthetic wound infiltration with 20 ml of 0.25% bupivacaine injected subcutaneously above and below skin incision before closure of skin.<br />Group C: Narcotics only group formed of 20 patients<br />• Routine analgesic was taken only without any intervention<br />Post-operative settings:<br />• At the end of the surgery and complete recovry<br /> <br /><br /><br /> <br />from anesthesia, the patient will be kept under observation postoperatively for 4 hours to monitor vital signs (conscious level, blood pressure, heart rate, respiratory rate and pattern & any possible limb weakness or abnormal sensation) then discharged to ward & observed to be followed for returning of pain.<br />• Duration of surgery (time from the start of skin incision to the end of skin closure) will be recorded.<br />• The patients will be observed for the occurrence of any adverse effect and/or complication related to the procedure (e.g. hematoma), or to the study drugs (e.g. hypotension/hypertension (i.e. 20% decrease or increase from the baseline value), bradycardia (HR <50 beats/min) or tachycardia (HR >120 beats/min), nausea, vomiting, and hypoxemia (SpO2 <90%).<br />• Assessment of pain involves asking a patient to rate her pain from 0 to 10 (VAS) with the understanding that 0 is equal to no pain and 10 equal to the worst possible pain after first hour, 2nd hour, 4th hour, 6th hour, 12th hour and 24th hour at wards after end of surgery.<br />• Pain is usually managed by pethidine IV based on patient complain. The analgesic dose of pethidine will be 50 mg to be repeated on demand (provided that the total 24 hour dosage will not exceed 150 mg. At recovery room mothers asked to report their pain based on VAS score during first 24 hour. Patient satisfaction from postoperative analgesia will be assessed at 24 hours postoperatively using a 5-point scale (1 = very unsatisfied, 2 = unsatisfied, 3<br />= fair, 4 = satisfied, and 5 = very satisfied) after first hour, 2nd hour, 4th hour, 6th hour, 12th hour and 24th hour at wards after end of surgery.<br />• A time in minutes from end of surgery to first analgesia request were documented together with total analgesia consumed in the first 24 h. In addition, incidence of postoperative nausea and vomiting will be documented within 24 h.<br />Operational definitions<br />Postoperative pain: The presence of pain in the postoperative period was defined as a patient complaining pain and any pain score other than zero within 24 h.<br />Time to first analgesia request: A time in minutes from the end of surgery to a first time analgesia requested by the patient.<br />Total analgesia consumption: Total dose of analgesic medication given in mg within the first 24 h after end of surgery.<br />Visual analogue scale: The patient marks on the line the point that they feel represents their perception of their current state. The VAS score is determined by measuring in<br /> <br />millimeters from the left hand end of the line to the point that the patient marks.<br />Statistical methods: The collected data will be coded, tabulated, and statistically analyzed using IBM SPSS statistics (Statistical Package for Social Sciences) software version 22.0, IBM Corp., Chicago, USA, 2013.<br />Descriptive statistics will be done for quantitative data as minimum& maximum of the range as well as mean ± SD (standard deviation) for quantitative normally distributed data, median and 1st& 3rd inter-quartile range for quantitative non-normally distributed data, while it will be done for qualitative data as number and percentage.<br />Inferential analyses will be done for quantitative variables using Shapiro-Wilk test for normality testing, ANOVA test and Kruskal Wallis test for more than two independent groups with non-normally distributed data. In qualitative data, inferential analyses for independent variables will be done using Chi square test for differences between proportions and Fisher’s exact test for variables with small expected numbers. Log rank test will be used to test survival functions. The level of significance will be taken at P value <0.050 is significant, otherwise is non- significant.<br />RESULTS<br />Tab. 1. shows that, no significant statistical differences between the studied groups regarding demographic characteristics; maternal age, body mass index and parity as well as gestational age and operation time.<br />Tab. 2. shows that, postoperative patients,’ pain perception in the studied groups increased slowly in TAB and WI group in the first six hours to reach its peak in hour 12, then decreased rapidly until hour-24. While it increased rapidly in the first six hours to reach its peak in hour 6 then decreased slowly until hour-24. The peak was lowest TAP group, followed by WI group and highest in control group.<br />Postoperative patients’ pain perception at hours 1, 2, 4, 6, 12 and 24 was lowest in TAP group, followed by WI group and highest in control group, the differences were statistically significant between all the studied groups but at hours 1 and 2 the differences were statistically significant between control and each of TAP and WI groups with no significant difference between TAP and WI groups. Tab.<br />3. shows that, time to first rescue analgesia was longest in TAP group, followed by LW group and shortest in control group, the differences were statistically significant between all the studied groups. Tab. 4. shows that, total NSAID dose was lowest in TAP group, followed by LWI group and highest in control group, the differences were statistically significant between the studied groups. Tab.<br />5. shows that, opioid consumption was least required in TAP group, followed by WI group and most required in control group, the differences were statistically significant between all the studied groups. Tab. 6. shows that, time to first opioid dose was least in TAP group, followed by WI