guided transversus abdominis plane (TAP) - Wiley Online Library

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Jul 28, 2016 - Aim: The aim of this study was to evaluate the effect of TAP block on the modification of ... It acts by blocking the anterior branches of the spinal.
Pediatric Anesthesia ISSN 1155-5645

RESEARCH REPORT

The effect of ultrasound-guided transversus abdominis plane (TAP) block on postoperative analgesia and neuroendocrine stress response in pediatric patients undergoing elective open inguinal hernia repair Mohamed M. Abu Elyazed, Shaimaa F. Mostafa, Mohammad A. Abdullah & Gehan M. Eid Department of Anesthesia and Surgical Intensive Care, Faculty of Medicine, Tanta University, Tanta, Egypt

What is already known

• TAP block is effective as a part of multimodal analgesia for children. What this article adds

• TAP block can cause significant attenuation in the neuroendocrine stress response induced by surgery.

Keywords child; pain; local anesthetics; regional; general anesthesia; measurement Correspondence DR. Shaimaa F. Mostafa, Department of Anesthesia and Surgical Intensive Care, Moheb Street, Almahalla Alkobra 31951, Egypt Email: [email protected] Section Editor: Adrian Bosenberg Accepted 28 July 2016 doi:10.1111/pan.12999

© 2016 John Wiley & Sons Ltd Pediatric Anesthesia 26 (2016) 1165–1171

Summary Background: Transversus abdominis plane block (TAP) is a compartmental block of the anterior abdominal wall. Surgical trauma produces multisystem reactions. Anesthetic techniques can modify the neuroendocrine surgical stress response. Aim: The aim of this study was to evaluate the effect of TAP block on the modification of the surgical neuroendocrine stress response as well as its analgesia effect in children undergoing open inguinal hernia repair. Method: Sixty children aged 3–10 years undergoing elective unilateral open inguinal hernia repair were randomized into group I (general anesthesia) or group II (received TAP block after induction of general anesthesia). Serum cortisol, blood glucose, quality of analgesia, postoperative need for rescue analgesia, and complications and degree of satisfaction of the patients and their parents were assessed. Results: Serum cortisol level was significantly lower in group II as compared to group I intraoperatively (17.73  1.51 vs 21.80  2.22 lgdl 1) and 30 min postoperatively (15.03  1.56 vs 18.30  1.53 lgdl 1). Blood glucose level was significantly lower in group II as compared to group I intraoperatively (107.57  3.77 vs 115.40  6.30 mgdl 1) and 30 min postoperatively (104.13  3.78 vs 110.73  4.83 mgdl 1). The quality of analgesia as indicated by CHEOPS and OPS scales was significantly better in group II. The consumption of postoperative rescue analgesia was significantly higher in group I as compared to group II (27.00  9.97 vs 13.00  9.43 mgkg 1). Conclusion: TAP block is effective as a part of multimodal analgesia for children undergoing open inguinal hernia repair with significant attenuation in the neuroendocrine stress response induced by surgery.

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Stress response and analgesia with TAP block

Introduction Transversus abdominis plane block (TAP) is a compartmental block of the anterior abdominal wall. It was described by Rafi in 2001 in adult patients (1). Subsequently, Hebbard described an ultrasound-guided technique (2). It has been adapted for pediatric (3) use. It acts by blocking the anterior branches of the spinal nerves from T7-L1 in the anterior abdominal wall lying in the neurofascial plane between internal oblique and transverses abdominis muscles (4). Abdominal surgeries are accompanied by considerable postoperative pain, which is an important variable in the surgical stress response and outcome. Opioids are widely used, often as patient-controlled analgesia (PCA). However, their side effects limit their efficacy. Therefore, there is a need for variable alternatives like TAP (4). Surgical trauma produces multisystem reactions. These reactions involve many endocrine, metabolic, hematological, as well as immunological reactions resulting from sympathetic activation (5). The severity of the stress response is directly related to the intensity of the surgical trauma (6). Surgical stress response is initiated by neuronal activation of the hypothalamic–pituitary–adrenal axis causing an increase in the secretion of endogenous catecholamines and glucocorticoids (7). The release of inflammatory mediators from the surgical site might also be responsible for the development of the stress response due to activation of the hypothalamus– pituitary–adrenal axis (5). The aim of our study was to evaluate the effect of TAP block on the modification of the surgical neuroendocrine stress response as well as its analgesia effect in pediatric patients scheduled for open inguinal hernia repair. Patients and methods The study was approved by the hospital ethics committee. Trial registry was done in the Pan African Clinical Trials Registry (PACTR 201604001562352). After obtaining informed written consent from the patient’s parents, children aged 3–10 years, of either gender, ASA I-II, undergoing elective unilateral open inguinal hernia repair were enrolled in the study. The duration of the study was 6 months from July to December 2015. All patients’ data were confidential with secret codes and in a private file for each patient. Every patient’s parents received an explanation for the purpose of the study and had a secret code number to ensure privacy to participants and confidentiality of the data. Exclusion criteria: children with the following illness were excluded from the study; children with metabolic 1166

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abnormalities, children with contraindications to TAP block, i.e., distorted anatomy at the site of injection, cardiac patients, patients with sepsis, renal dysfunctions, and children with known hypersensitivity to relevant drugs. Patients were randomly allocated into two groups with 1 : 1 ratio. Randomization was performed using the sealed opaque envelope technique; each patient’s parent randomly selected a sealed envelope containing a group number in which the patient was enrolled. An investigator who had no subsequent role in the study opened the selected envelope. All operations were performed in the morning as the first case of the schedule to equalize circadian changes in the stress hormone levels. All children were premedicated orally with midazolam 0.5 mgkg 1 30 min prior to surgery. Group I: patients received general anesthesia only. Group II: patients received ipsilateral ultrasoundguided transverses abdominis plane (TAP) block following induction of general anesthesia. All patients were monitored by five-lead ECG, pulse oximetry, noninvasive blood pressure, and capnography. A warming blanket was used to prevent hypothermia during surgery. The technique of general anesthesia and postoperative analgesia was standardized for all patients. General anesthesia induction was performed by intravenous 2 mgkg 1 propofol and 1 lgkg 1 fentanyl. After i.v. atracurium 0.5 mgkg 1, orotracheal intubation was performed. Anesthesia was maintained with a mixture of air, oxygen, and (0.5–1.5%) isoflurane. Muscle relaxation was maintained during the procedure with atracurium (0.1 mgkg 1). Patients were ventilated with tidal volume and respiratory rate adjusted such that endtidal CO2 (PECO2) is maintained at 4.6  0.25 kPa (35  2 mmHg). Technique of ultrasound-guided transverses abdominis plane (TAP) block After induction of general anesthesia, the procedure was done under ultrasound guidance using high frequency linear 6–13 MHz transducer (SonoScape SSI 6600China). Visioplex 50 mm 22 gauge needles (Vygon, France) were used. With the patient in the supine position and under complete aseptic technique, the ultrasound probe was placed ipsilaterally on the abdominal wall at the level of the umbilicus. After visualization of the rectus abdominis muscle, the probe was moved laterally halfway between the iliac crest and the costal margin. When the three musculofascial layers of the abdominal wall were visualized, the needle was inserted © 2016 John Wiley & Sons Ltd Pediatric Anesthesia 26 (2016) 1165–1171

M.M. Abu Elyazed et al.

between internal oblique and the transverses abdominis muscles within the plane approach. About 0.4 mlkg 1 of bupivacaine 0.25% was injected after negative aspiration to avoid intravascular injection. The total dose of bupivacaine would not exceed 2 mgkg 1 and the total volume would not be more than 20 ml. D5 ½ normal saline was used at rate of 5 mlkg 1h 1. Increase in heart rate or mean arterial blood pressure (MAP) more than 20% above the baseline was used as indicator for inadequate analgesia; fentanyl 0.5 lgkg 1 was given. After the end of surgery, extubation was performed when spontaneous breathing was adequate and following prompt reversal with neostigmine (0.05 mgkg 1) and atropine (0.02) mgkg 1. After the end of surgery, patients were transferred to the postanesthesia care unit (PACU), where heart rate (HR), respiratory rate, SpO2, and systolic, diastolic, and mean pressures were monitored and any changes were recorded immediately. Pain assessment was done using Children’s Hospital Eastern Ontario Pain Scale (CHEOPS) and Objective behavioral pain score (OPS) scores. CHEOPS score includes six items (Facial 0-2, Child verbal 0-2, Torso 1-2, Cry 1-3, Touch 1-2, and Legs 1-2). The CHEOPS score ranges from 4–13. OPS scale consists of five items (Blood pressure 0-2, Crying 0-2, Movement 0-2, Anxiety 0-2, and Posture 0-2) and ranges from 0–10. Diclofenac suppository 25 mg/8 h was given for postoperative analgesia. Rescue analgesia in the form of paracetamol 15 mgkg 1 IV was given if OPS score was >5 or CHEOPS score >6. Measurements All measurements were recorded by an independent investigator. 1. Serum cortisol and blood glucose were used for evaluation of the stress response before induction of general anesthesia, 30 min after surgical incision, 30 min postoperative at and 24 h after the end of surgery. 2. MAP and HR were recorded in the following times: preoperative (T0), after endotracheal intubation (T1), 15 min after skin incision (T2), 30 min after skin incision (T3), at the end of surgery (T4), and postoperatively at the following times on admission to PACU, 2 h, 4 h, 8 h, 12 h, 16 h, and 24 h (T5, T6, T7, T8, T9, T10, T11, respectively). 3. CHEOPS and OPS scales were assessed immediately postoperatively on admission to PACU and then at 2 h, 4 h, 8 h, 12 h, 16 h, and 24 h postoperatively. 4. Postoperative need for rescue analgesia and its time and total dose/24 h. 5. Complications such as nausea, vomiting, infection, or hematoma, and the length of hospital stay. © 2016 John Wiley & Sons Ltd Pediatric Anesthesia 26 (2016) 1165–1171

Stress response and analgesia with TAP block

6. Degree of satisfaction of the patients and their parents assessed on a 3-point scale (1 = dissatisfied, 2 = not satisfied nor dissatisfied, 3 = satisfied). Statistical analysis Calculation of the sample size was based on the attenuation of neuroendocrine stress response. Depending on the previous study (8), a sample size of 24 patients was found to be needed to detect a difference at the 5% significance level and give the trial 80% power. Sample size was calculated and assured using Power and Sample Size Calculation Software program provided by Department of Biostatistics, Vanderbilt University. We used SPSS 16 for statistical analysis. Quantitative data were described as mean  SD and independent sample t-test was used for comparison between both groups. Categorical data were described as proportion and chi-square test was used for comparison between both groups. P value