A hospital based parallel design, phase three two armed feasibility study conducted from 1st May to 31st June 2019 at KCMC referral hospital obstetrics operating room 1 and 2 and in the post ceasarean wards. KCMC is a 700-bed tertiary teaching hospital with a catchment population of 15 million and is located in northern Tanzania. KCMC has 55 obstetric beds and on average 4 cesarean sections per day are performed (KCMC report, 2018).
Ethical approval was obtained from the Research Ethics Review Committee of the Kilimanjaro Christian Medical University College (KCMUCo) with certificate no 2394 and permission to conduct the study was granted by the KCMC hospital. Trail was Register in Pan African Clinical Trial Registry (PACTR) with no PACTR202011815473426 on 12 November 2020.
All parturient participants classified as ASA II and III planned for cesarean section at KCMC during the study period and concented were enrolled in this study.
Participants with communication difficulties, obesity ( BMI > 30), any contraindication of spinal anaesthesia, allergic to amino-amide local anesthetics such as bupivacaine, coagulopathy, and local skin infection at any injection sites.
All parturient women planned for emergency or elective caesarian section who met the inclusion criteria were recruited to join the study. Initially, the demographic data was extracted from the parturient files into the data sheets and then they were presented with all the information regarding the study. This information included benefits and disadvantages of the study and all their questions were satisfactorily responded to and finally, they were asked to sign the consent. They were informed refusal to consent would not jeopardize further treatment at KCMC.
During preparation for cesarean section all participants were treated as per KCMC Obstetrics protocols with an exception that ultrasound-guided TAP block was administered to participants in group A. In the operating room, patients were placed on left lateral position and monitors were placed to obtain baseline vitals of the parturient and the fetus. Then IV pre-loading with 500 ml to 1000 ml Ringers solution was started and pre-operative antibiotic was administered. They were all operated under spinal anaesthesia using a G25 LUCKmed quinkle needle with 2 ml (10 mg) of 0.5% heavy bupivacaine (BUPICAN 0.5% Claris 4 ml ampule). All spinal anaesthesia were administered in seating position. Before surgery participants were randomized into groups A and B by picking an envelope from a box. After surgery Group A was subjected into intervention as per study protocol..
At the end of the surgery, bilateral ultrasound guided TAP block was performed by the principal investigator using 60 ml of 0.25% plain bupivacaine (BUPICAN 0.5% Claris 20 ml vial), 30 ml each side. The bupivacaine aliquots were prepared by mixing 15 ml of 0.5% bupivacaine with 15 ml of water for injection at the bed side and the block was administered using aseptic non-touch technique (ANTT).
After preparing the skin with an antiseptic solution, a linear high frequency ultrasound probe (6–13 MHz, Sonosite M- Turbo©) was placed transversely on the anterolateral abdominal wall between the iliac crest and the costal margin. The three layers of muscles i.e. external oblique, internal oblique, and the transversus abdominis were identified. To assist with identifying these structures, the probe was moved anteriorly to the rectus sheath and the fascial planes were followed laterally .
A sterile 22-gauge, 115-mm Quincke needle was attached to a syringe containing 10 ml water for injection via a flexible tube connector. The sterile water was used to locate the position of the tip of the needle in the fascial plane by hydro dissection. The needle was introduced through the skin anteriorly in the plane of the ultrasound beam and advanced further into the fascial plane between the internal oblique and transversus abdominis muscles with its tip lying in the mid axillary line. After aspiration to exclude inadvertent vascular puncture, 2–5 ml of sterile water was used to separate the fascial planes. Then 30 ml of the aliquot was administered while closely observing for signs (tinnitus, perioral numbness, metallic taste in the mouth) and symptom (slurring of speech, mental status changes, increase in QT,widen QRS, ectopic beats and hypotension) of toxicity. TAP block was performed in a similar fashion on the opposite side.
After completion of the procedure, patients were shifted to the recovery for 30 minutes monitoring before they were transferred to the obstetric ward. Both groups received post-operative pain treatment according to the KCMC protocol.
Pain was assessed by a blinded independent observer immediately after delivery (0hr), 6hrs, 12hrs and 24 hrs.
Primary outcomes were the pain score, which was assessed by using numerical rating scale (NRS) and function assessment by using pain scores on physical activities such as turning in bed, sitting, standing, walking and coughing. Patients were asked to rate the intensity of pain out of ten using NRS. It a 10-point numerical rating scale with end points representing the extremes of the pain experience: 0 = “no pain at all” and 10 = “worst possible pain”. The score was classified as mild pain when the score is 0 to 3, moderate pain when the score is 4 to 7 and severe pain when the score is 8 to 10 
NRS is the most commonly recommended tool in pain studies due to better responsiveness and compliance, easy to use and applicababilty in most settings compared with visual analog scale/verbal rating scale (VAS/VRS) . It is difficult to assess pain objectively, although it can be assessed at rest and during movement by NRS to detect changes and difference in pain scores. Functional assessment was assessed by functional activity including turning in bed, sitting, standing and walking was marked on a numeric rating scale ranging from zero = “no pain” to 10 = “maximum pain”. . Thus, all these two were assessed at 0hrs, 6hrs, 12hrs and 24hrs.
Patients satisfaction, question was adopted from the 5-point Likert scale ranging from 1 = very dissatisfied to 5 = Very satisfied. Participant were asked two questions on were they satisfied with information of TAP block and 24 pain management. It improves learners’ perceptions of readiness, knowledge and prioritization skills by 30–45% (McGillion et al., 2011; Farooq, Khan and Ahmed, 2016). A pilot study was conducted with 20 patients to validate the data collecting tool and further categorized into 3-point Likert scale for easy analysis. And complications of TAP block were assessed such as LAST which was light headedness, blurred vision, tinnitus, metallic test on the tongue, confusion and loss of consciousness. Patients satisfaction was assessed at 24hrs and complications were assessed all the time up to 24hrs.
Criterial for stop intervention
Criteria for stop intervention were refusal by the participant at any point in time, sign of LAST which was Lighted headedness, blurred vision, Tinnitus, metallic test on the tongue, confusion and loss of consciousness and those transferred to intensive care unit (ICU). No other medications or procedures were discontinued, denied, delayed or prevented as a result of an intervention of this study.
For study with 80% power to detect 30% difference VAS pain score between two groups P-value 0.05 for clinically significant. And standard deviation of 10 with 10% fall out a sample size of 68 participants (34 to each groups) .
Randomization was done by using numbers (from 1 to 86) that were written on a piece of paper which was enclosed in 86 envelopes. These envelopes were mixed and put in one pool from which each participant picked one envelop to disclose the number to the principal investigator. Patients who picked even numbers were assigned to group A (intervention group) and those with odd numbers were assigned to group B (control group). with parallel design through number from 1 to 80 all even numbers were group A (TAP group) and odd numbers were assigned group be (control group).
Blinding was done complete research assistant who was going to assess the participant. Although full blinding of participants to condition in this study was not possible, several strategies were employed to reduce the risk of bias. First, information of the study hypothesis was provided to participant. Second participants were clearly instructed only to contact the investigator personally using a phone number provided to them by the investigator and direct to him alone all queries regarding the intervension, to avoid contact with the research assistant for any scheduling concerns, questions regarding intervention.
During data collection, special codes were used in place of parturient name then it was double entered into data collecting sheet. Later on, it was cleaned and analyzed using SPSS V24. Descriptive statistics was carried out to describe the socio-demographic and clinical characteristics of the participants were summarized in form proportions, frequency tables and bar charts for categorical variables and Mean and standard deviation used to for continuous. Bivariate analysis using Chi-square test was used to find out the association followed by a logistic regression. Independent t-test was used to compare mean pain score between different groups of patients. Statistical differences was determined at 95% confidence interval with a P < 0.05.