Research and Opinion in Anesthesia & Intensive Care Volume 2

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1 Ultrasound guided transversus abdominal plane (TAP) block versus caudal block for postoperative analgesia in children undergoing unilateral open inguinal herniotomy: a comparative study Dr. Ashraf A. Ahmed., Assistant professor of anesthesia Ain Shams University, Dr. Ayman A Rayan Lecturer of anesthesia Minoufia University Introduction The abdominal wall consists of three muscle layers, the external oblique, the internal oblique, and the transversus abdominis, and their associated fascial sheaths. The central abdominal wall also includes the rectus abdominis muscles and its associated fascial sheath. This muscular wall is innervated by nerve afferents that course through the transversus abdominis neuro-fascial plane. A promising approach to the provision of postoperative analgesia after abdominal incision is to block the sensory nerve supply to the anterior abdominal wall (). Caudal epidural block (CEB) involves injection of a drug into the epidural space through the sacral hiatus to provide analgesia and anesthesia in various clinical settings (). We thus conducted a prospective randomized study to compare the efficacy of the ultrasound-guided TAP block and conventional caudal block on both immediate postoperative pain after inguinal hernia surgery performed in day-case patients. Methods The study was performed in the period August to November, in Armed Forces Hospital- DHAHRAN After obtaining approval by the Hospital Ethics Committee, and written informed patient consent, we studied 4 ASA physical status I II patients aged between -6 years scheduled for elective outpatient unilateral groin surgeries in a prospective, randomized, double-blind, controlled clinical trial. Patients were excluded if there was patient parental refusal, any contraindication to caudal block e.g. bleeding disorders, a history of relevant drug allergy or inability to see the trasversus abdominis plane on ultrasound. For what concern the technique using a SonoSite 8 plus transportable ultrasound unit and a 5 MHz linear hockey stick probe with an active area of 5 mm (SonoSite, Bothell, WA) ultrasound probe, is placed in a transverse plane to the lateral abdominal wall in the mid axillary line between the lower costal margin and iliac crest. The tip of the needle needs to be positioned between the internal oblique and the transversus abdominis muscle in the fascial layer that separates the two muscle layers (Fig ). Patients were randomized, by sealed envelope technique, to undergo ultrasound guided TAP block (n = ) using A predetermined volume of local anesthetic (.-.3 ml/kg in pediatric patients; is injected on the side of operation as single shot under ultrasound guidance..5 ml/kg.5% bupivacaine in group I or to receive caudal block using ml/kg.% bupivacaine (n = ) in group II. The patients, their anesthesiologists, and the staff providing postoperative care were blinded to group assignment. Both TAP and caudal were done by the same anesthetist. All patients received general anesthetic by induction with 8% sevoflurane via facemask, after laryngeal mask insertion, it was secured and anesthesia maintained with % MAC sevoflurane in 6% nitous oxide and oxygen. Standard monitoring, including electrocardiogram, arterial blood pressure, arterial oxygen saturation, and end-tidal carbon dioxide monitoring were used throughout, and patients were placed in the supine position. 5

2 Fig Transverse ultrasound view of the EOAM, IOAM, and TAM. After induction of general anesthesia, caudal block or unilateral TAP block was performed under ultrasonographic guidance with a SonoSite M-Turbo transportable ultrasound device (SonoSiteTM, Bothell, WA, USA) and a linear 6 3 MHz ultrasound transducer. Once the EOAM, IOAM, and TAM were visualized at the level of the anterior axillary line between the costal margin and the iliac crest, the puncture area and the ultrasound probe were prepared in a sterile manner. Then, the block was performed with a G 5 mm Facette tip needle and an injection line (Stimuplex A B BRAUN Melsungen AG, Germany) realizing an inplane ultrasound-guided technique. Once the tip of the needle was placed in the space between the IOAM and TAM and negative aspiration, bupivacaine.5% was administered under direct ultrasonographic guidance. The satisfactory image was aimed to visualize the subcutaneous fat, external oblique muscle, internal oblique muscle, transversus abdominis muscle, peritoneum cavity. Successful injection was obtained when an echoluescent lens-shaped appeared between the two muscles. Skin incision was given in both study groups 5 min after the TAP block or caudal block. Hemodynamics, 5 min after laryngeal mask insertion, were taken as baseline. If heart rate, non-invasive arterial pressure, or both increased by 5% relative to the baseline measurements, fentanyl ug/kg was administered. The total amount of fentanyl administration was recorded. Failure of caudal or TAP blocks was defined as increase in HR or MAP more than % of pre-incision value. After operation, the patients were admitted to the recovery room, vital signs were observed every 5 min. The patients stayed for 4 h in the recovery room. During the h in the recovery room the sites of injection of the TAP block or caudal area were inspected to detect side-effects such as hematomas or infection. The efficacy of postoperative of postoperative analgesia was documented using the objective variables (crying, facial expression, position of torso and legs, motor restlessness) were assessed. Postoperative analgesia was evaluated by the children and infants postoperative pain scale (CHIPS). CHIPS are well-validated and reliable scale in determining postoperative analgesia demand in children (table ). The children were monitored hourly for at least 4 h after operation before discharge from the outpatient surgical unit. Table The children and infants postoperative pain scale (CHIPS). Item Structure Points Crying None Moaning Screaming Facial expression Posture of the trunk Posture of the legs Motor restlessness Relaxed/smiling Wry mouth Grimace (mouth and eyes) Neutral Variable Rear up Neutral, released Kicking about Tightened legs None Moderate Restless An anesthesiologist, who was not part of the study team, evaluated the need for rescue analgesia in the intraoperative and postoperative period and recovery nurse collected the data. If the OPS score was >, rescue analgesia of 3 mg. kg acetaminophen was administered. 53

3 Data are presented as mean (SD), number (%), or ratio as appropriate. The calculation assumed the use of Fisherʹs exact test. Chi-square test was used to compare between patients in TAP block and caudal block for nominal variables i.e. sedation, satisfaction, Results Forty patients were included in the study ( in each group); all participants had elective outpatient groin surgeries (inguinal hernia repair). The baseline characteristics of the two groups were not significantly different (Table ). Ultrasound views were satisfactory in all patients in TAP block group. Ultrasonographic postoperative nausea and vomiting. Studentʹt-test was used for independent groups to compare between both groups for measurable variables i.e. age, weight, height, acetaminophen dose and CHIPS score. P-values of,.5 were considered significant. visualization of the external, IOAM, and TAM, of the needle, and of the spread of local anesthetic was possible in all TAP blocks. No case of blood aspiration during performance of TAP blocks was observed. On the other hand the caudal block group threre was one patient with blood aspiration and the trial repteated twice untill the caudal injection was satisfactory Table Baseline characteristics of the study participants Parameter TAP block group group (Group I) (Group II) Age (yrs)(mean) { Range } 3.75± ±.39 >.5 Sex (, ) = = 8 = 9 = ASA I II Weight (kg) 5.93± ±.776 >.5 Height (cm) 4.5±7.46.9±8. >.5 Table 3 Surgical data Parameter TAP block Group Group (Group I) (Group I) Duration of surgery 7.± ±4.87 >.5 Duration of anesthesia 4.35± ±5.59 >.5 Table 4 Changes of heart rate in both groups: TAP block Group (Group I) (beat min) Group (Group II) (beat min) Baseline 3.5±.4 7.±6.8 >.5 Before incision 3.3± ±9.3 >.5 Response to incision 33.7± ±5.4 >.5 5 min 8.6±7. 3.±8. >.5 min 5.6± ±.4 >.5 5 min 4.±6.6.±3.9 >.5 min 3.5± ±8.5 >.5 54

4 TAP block Group Group Baseline Before incision Response to incision 5 min min 5 min min Fig 3 Changes of heart rate in both groups Table 5 Changes of mean blood pressure in both groups: TAP block Group (Group I) (mmhg) Group (Group II) (mmhg) Baseline 86.± ±8.8 >.5 Before incision 93.9±. 9.3±7.8 >.5 Response to incision 94.6± ±8.9 >.5 5 min 9.4±.5 94.±9.4 >.5 min 89.4± ±7.8 >.5 5 min 88.5± ±. >.5 min 87.9± ±9.7 > SeTAP block Group Group 55

5 Figure 4 Changes of mean blood pressure in both groups: Table 5 Amount of intraoperative fentanyl TAP block Group (Group I) Group (Group II) Amount of introperative.5±5.6.5±4.7 <.5 fentanyl (ug) TAP block group caudal block group Column Column Figuer 5 Amount of intraoperative fentanyl Table 6 Children and infants postoperative pain scale (CHIPPS) Children and infants postoperative pain TAP block group scale (CHIPPS) (Group I) group (Group II) ST HOUR.5±.93 ±.85 >.5 ND HOUR.±.85.±. >.5 3RD HOUR.55±.6.4±.59 >.5 4TH HOUR.6±.5.85±.36 >.5 There was no significant difference between TAP block and caudal block children and infants postoperative pain scale (CHIPPS) 56

6 3.5.5 TAP block group group.5 ST HOUR ND HOUR 3RD HOUR 4TH HOUR Fig 5 Children and infants postoperative pain scale (CHIPPS) No side effects were observed during 4 hours of the surgery in TAP block while two patients in caudal block group complaining from vomiting; both patients given antiemetic drug. Discussion Ultrasonographic-guided TAP block suggest improved block qualities and safety, which is mainly due to direct visualization of the relevant anatomy, the tip of the needle, and the spread of local anaesthetic (3). Consequently, direct visualization of all anatomical structures, the needle, and the spread of local anaesthetic by ultrasonographic guidance may be associated with an increased margin of safety and optimal block qualities. In the study done by Joseph., 8.,(4) it was found the TAP block provided effective analgesia following subumblical and lower abdominal procedures in infants and children, when compared with the usual practice of caudal analgesia., this was in agreement with this present study. In agreement with our study the study done by Frederickson et al., 8, (5) unilateral TAP block has been shown to provide effective analgesia for inguinal hernia repair The TAP block technique was developed recently as a result of the clinical need for a simple and efficient analgesic technique for abdominal procedures, including inguinal hernia repair, hysterectomy and cesarean delivery (6)(7)(8). No cases excluded in both groups; three patients in TAP block and one patient in caudal block group, heart rate increased but less than 5% in relation to the base reading. In pediatric patients indications for TAP block are laparotomy, appendectomy, major abdominal wall surgery, colostomy placement and closures (9). In fact, in many surgical procedures a good level of analgesia can be obtained. An interesting study has been recently published about the effectiveness of TAP block in 64 pediatric patients aged 5- years receiving bone graft from the ilium to the alveolar cleft. In these patients analgesia was effective with a significant reduction of postoperative analgesic rescue drugs (). The optimal analgesic regimen should provide safe, effective analgesia, with minimal side effects for the child. A multimodal analgesic regimen is most likely to achieve these goals; however, the optimal components remain to be determined. The TAP block provides blockade of nociception from the abdominal wall; however, there is also nociceptive input from the abdominal organs and the onset of the block is not immediate. Therefore, the block is used as part of a multimodal approach. This trial demonstrated that an ipsilateral TAP block provides effective analgesia in children undergoing groin surgeries. Ultrasound TAP block seems to be useful in reducing opioid requirements and opioid-related side-effects in patients following major abdominal surgery. This 57

7 aspect represents a great advantage versus epidural anesthesia due to a reduction of hemodynamic changes. The pre-op, intra-op and post-op hemodynamics variables between the groups were comparable and were not statistically significant and therapeutic interventions were not required. No clinically significant postoperative complications such as PONV, respiratory depression, urinary retention, pruritus, hypotension, and bradycardia were observed. In our study no cases complained from nausea or vomiting postoperative (PONV)., this is in contrast to the study done by Petersen et al () indicated that patients may suffer less from PONV., while the study done by Aveline et al., ()., 8.% of the patients complained from PONV while in the present studies indicate that patients may suffer less from PONV and sedation with the TAP block. The ultrasound techniques allow avoiding or reducing a great number of complications described for traditional procedures using landmarks. A case of ultrasoundguided TAP block causing liver trauma and bleeding in a patient undergoing an inguinal hernia repair has been described, perhaps for using an inappropriate ultrasound machine (3). Our study has several limitations. The anesthetist in charge of the patient was not blinded for the block technique. However, patients were blinded for the type of block and anesthetists and surgeons conducting postoperative assessments were unaware of the randomization. In conclusion, after open inguinal hernia repair in ambulatory patients, both ultrasound-guided TAP block caudal analgesia provided better immediate postoperative pain relief and reduced opioid demand as well as improved pain scores in inguinal hernia repair, and no clinical significant postoperative complications were observed. References () Kuppuvelumani P, Jaradi H, Delilkan A. Abdominal nerve blockade for postoperative analgesia after caesarean section. Asia Oceania J Obstet Gynaecol 993;9:65 9. () Chen PC, Tang SFT, Hsu TC, et al. Ultrasound guidance in caudal epidural needle placement. Anesthesiology 4; : 8 4 (3) Willschke H, Bosenberg A, Marhofer P, et al. Ultrasonographyguided rectus sheath block in paediatric anaesthesia a new approach to an old technique. Br J Anaesth 6; 97: (4) Joseph D Tobias. Preliminary experience with transversus abdominis plane block for postoperative pain relief in infants and children. Saudi Journal of Anesthesia, Vol 3, No, April 9-6. (5) Frederickson M, Seal P, Houghton J. Early experience with the transverses abdominis plane block in children. Pediatr Anesth 8;8:89-89) (6) Kuppuvelumani P, Jaradi H, Delilkan A. Abdominal nerve blockade for postoperative analgesia after caesarean section. Asia Oceania J Obstet Gynaecol 993;9:65 9 (7) McDonnell JG, Curley G, Carney J, Benton A, Costello J, Maharaj CH, Laffey JG. The analgesic efficacy of transversus abdominis plane block after cesarean delivery: a randomized controlled trial. Anesth Analg;6:86 9 (8) Carney JJ, McDonnell JG, Bhinder R, Maharaj CH, Laffey JG. Efficacy of transversus abdominis plane block using ropivacaine in multimodal postoperative pain relief in total abdominal hysterectomy surgery. Reg Anesth Pain Med 7;3:37 (9) Suresh S, Chan VW. Ultrasound guided transversus abdominis plane block in infants, children and adolescents: a simple procedural guidance for their performance. Paediatr Anaesth. 9; 9: () Tanaka M, Mori N, Murakami W, Tanaka N, Oku K, Hiramatsu R, Nakagawa M, Yasumoto K. The effect of transversus abdominis plane block for pediatric patients receiving bone graft to the alveolar cleft. Masui. ; 59: () P. L. PETERSEN, O. MATHIESEN, H. TORUP and J. B. DAHLThe transversus abdominis plane block: a valuable option for postoperative analgesia? A topical review.acta Anaesthesiol Scand ; 54: () C. Aveline, H. Le Hetet, A. Le Roux, P. Vautier, F. Cognet, E. Vinet, C. Tison and F. Bonnet. Comparison between ultrasound-guided transversus abdominis plane and conventional ilioinguinal/ iliohypogastric nerve blocks for day-case open inguinal hernia repair.british Journal of Anaesthesia 6 (3): 38 6 () 58

8 (3) Tran TMN, Ivanusic JJ, Hebbard, Barrington MJ, Determination of spread of injectate after ultrasoundguided abdominis plane block; A cadaveric block. Br J Anesth 9; :