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| ORIGINAL ARTICLE |
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| Year : 2016 | Volume
: 9
| Issue : 3 | Page : 403-408 |
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Ultrasound-guided rectus sheath block for pediatric patients undergoing elective abdominal midline operations: a randomized controlled trial
Mostafa M Hussein Khalil MD
Department of Anesthesia, Intensive Care and Pain Management, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| Date of Submission | 07-Jun-2015 |
| Date of Acceptance | 12-May-2016 |
| Date of Web Publication | 31-Aug-2016 |
Correspondence Address:
Mostafa M Hussein Khalil
5 Abdel-Azim Salama Street, Nasr City, Cairo, 11727, Egypt
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/1687-7934.189570
Clinical trial registration PACTR201505001103180.
Background
Under high-resolution ultrasonic guidance, bilateral rectus sheath block (RSB) can be performed with higher success rate and fewer complications. RSB results in blocking the anterior branches of the lower thoracic spinal nerves supplying the central portion of the anterior abdominal wall.
Objective
The aim of the study was to assess the effectiveness of bilateral ultrasound-guided RSB in children undergoing elective midline abdominal operations.
Patients and methods
Fifty-six patients of both sexes between 2 and 10 years of age, of American Society of Anesthesiologists physical status I–II, undergoing elective midline abdominal procedures were involved in this randomized controlled trial. Patients were randomly allocated to one of two groups: 27 patients in group R (RSB group) and 29 patients in group C (control group). Both groups received general anesthesia. Group R received bilateral RSB with 0.3/ml/kg bupivacaine 0.25% under ultrasound guidance, and group C received regular analgesics. The primary outcome measure was degree of pain assessed using the Objective Pain Scale. The secondary outcome measures were hemodynamic parameters, intraoperative fentanyl requirement, and postoperative need for analgesia.
Results
Demographic and hemodynamic parameters were similar in both groups. Total intraoperative fentanyl requirement was significantly lower in group R compared with group C. Group R had a significantly lower pain score up to 24/h postoperatively compared with group C. The mean time to first postoperative rescue analgesia was significantly longer in group R (120.8±4.7/min) than in group C (48±3.6/min). The number of rescue doses of analgesia was significantly lower in group R [1 (0–1)] than in group C [3 (2–3)].
Conclusion
Bilateral RSB under ultrasound guidance provides effective intraoperative and postoperative analgesia with more stable hemodynamics in pediatric patients undergoing elective midline abdominal procedures. Keywords: anesthesia, pediatric, rectus sheath block, ultrasonography
How to cite this article:
Hussein Khalil MM. Ultrasound-guided rectus sheath block for pediatric patients undergoing elective abdominal midline operations: a randomized controlled trial. Ain-Shams J Anaesthesiol 2016;9:403-8 |
How to cite this URL:
Hussein Khalil MM. Ultrasound-guided rectus sheath block for pediatric patients undergoing elective abdominal midline operations: a randomized controlled trial. Ain-Shams J Anaesthesiol [serial online] 2016 [cited 2021 Oct 17];9:403-8. Available from: http://www.asja.eg.net/text.asp?2016/9/3/403/189570 |
| Introduction | |  |
The use of ultrasound as a guide for regional anesthesia has become common practice and a new challenge to anesthesiologists. Besides its benefits of reduced complications, it also helps in reducing the total anesthetic dose required with higher block success rates. There is also the advantage of direct observation of the pattern of anesthetic spread. Recently, ultrasound-guided rectus sheath block (RSB) was used to provide both surgical and postoperative analgesia for pediatric abdominal midline (or paramedian) procedures [1].
The postoperative pain after abdominal midline (or paramedian) operations is largely derived from the abdominal wall incision. In the past, abdominal field block was done in a blinded manner to provide analgesia for surgery<!-- of the anterior abdominal wall, but with the help of ultrasonography the technique has improved because of direct visualization and is thus safer to perform.
RSB provides somatic pain relief for abdominal wall structures superficial to the peritoneum. Therefore, for surgery deep to the peritoneum (such as bowel resection) there is usually a visceral pain component, which needs systemic analgesia. Effective postoperative analgesia after abdominal vertical incision (median or paramedian) has the advantage of accelerating recovery from surgery, decreasing the dose of postoperative rescue analgesia, and resulting in short hospital stay.
The central portion of the anterior abdominal wall is innervated by the anterior rami of the spinal nerve roots from T7 to L1. These nerves [i.e. the intercostal nerves (T7–T11), the subcostal nerve (T12), and the iliohypogastric/ilioinguinal nerves (L1)] run in the neurovascular plane between the internal oblique and the transversus abdominis muscles called the transversus abdominis plane, then pierce the rectus abdominis muscle (RAM) to lie between it and its posterior sheath, and end as anterior cutaneous nerves. The superior and inferior epigastric vessels run longitudinally through the medial portion of the muscle [2].
The absence of tendinous intersections at the posterior rectus sheath facilitates the craniocaudal spread of the local anesthetic within the ipsilateral compartment. The two rectus muscles are separated in the midline by the linea alba. The linea semilunaris is formed by the lateral border of the rectus muscle and its sheath. The arcuate line represents the inferior border of the posterior rectus sheath. The arcuate line is present midway between the umbilicus and the pubic crest. The superior epigastric artery (a branch from internal mammary artery) enters the rectus sheath inferior to the seventh costal cartilage. The inferior epigastric artery (a branch from external iliac artery) runs superiorly and enters the rectus sheath at the arcuate line.
The RSB was first described in 1899 by Schleich to enhance abdominal muscle relaxation during laparotomy before the use of neuromuscular block. Now it is used for analgesia after incisional or umbilical hernia repairs and other midline surgical incisions [3].
The technique has been further developed in some centers to include placement of the rectus sheath catheter, thereby facilitating continuous postoperative analgesia.
| Aim | | |
The aim was to evaluate the effectiveness of ultrasound-guided RSB regarding the degree of pain relief and hemodynamic stability in children undergoing elective abdominal midline procedures.
| Patients and methods | | |
After obtaining approval from the local ethical committee, 56 patients of both sexes, of American Society of Anesthesiologists physical status I–II, between 2 and 10 years of age, scheduled for elective abdominal midline operation in the Pediatric Surgery Department, Ain Shams University Hospital, were included in this randomized controlled study. The study was performed from June 2014 to April 2015. Informed consent was taken from the parents of all participating children.
Using sealed envelopes, patients were randomly allocated by means of computer-generated tables into two groups: group R (RSB group) and group C (control group). Patients with hepatic disease, bleeding or neurological disorders, known hypersensitivity to local anesthetics, evidence of peritonitis, sepsis, or infection at the site of needle insertion, and those who require emergency operations were excluded from the study.
The intravenous cannula was inserted in both groups before the induction of anesthesia. No premedication was given. Standard monitoring included three-lead ECG, heart rate (HR), noninvasive arterial pressure, oxygen saturation, capnography, and temperature monitoring. Baseline reading was recorded after attaching the patient to the monitors and before induction of general anesthesia.
General anesthesia was induced in both groups using propofol 2.5/mg/kg, fentanyl 1/μg/kg, and atracurium 0.5/mg/kg, and the trachea was intubated. Maintenance of anesthesia was done using isoflurane 1/MAC in oxygen and air (50% oxygen in 50% air) with maintenance dose of atracurium 0.1/mg/kg given every 20/min.
Patients in group R received bilateral sonar-guided RSB with 0.3/ml/kg bupivacaine 0.25%, whereas those of group C received fentanyl 1/μg/kg, which was given during induction.
Rectus sheath block procedure
After skin disinfection with povidone-iodine solution, the abdominal wall of patients in group R was scanned using a linear array transducer probe (6–13/MHz) connected to a portable ultrasound unit (GE healthcare, LOGIQ P5, Milwaukee, WI, USA). The appropriate depth, frequency, and gain are adjusted to optimize the image. The transducer is initially placed over the midline in the short axis plane to demonstrate the paired RAMs on either sides of the linea alba. The transducer is slipped from medial to lateral. The anterior and posterior aspects of the rectus sheath enveloping the RAMs were recognized. The anterior and posterior portions of the rectus sheath appear as hyperechoic linear structures on the superficial and deep aspects of the RAMs. As the transducer slid further lateral, the linea semilunaris was seen between the lateral border of the RAMs and the medial edge of the three lateral abdominal wall muscles (external oblique, internal oblique, and transversus abdominis muscles). The subcutaneous tissue is seen superficial to the anterior rectus sheath and the peritoneum is seen deep to the posterior rectus sheath.
A 22-G short bevel needle was inserted with in-plane ultrasound real-time assessment at a point above the umbilicus at the lateral border of the rectus abdominis. The progression of the needle, visible as a bright hyperechoic line, was assessed under direct ultrasonography. The correct placement of the needle was confirmed by expansion of the local anesthetic solution as a dark shadow between the rectus muscle and the posterior rectus sheath.
In both groups, any increase in the HR or arterial blood pressure during the surgical procedure by more than 20% of baseline values was compensated by an additional fentanyl dose of 0.5/μg/kg. At the end of surgery, isoflurane was discontinued and the muscle relaxant was reversed with atropine 0.02/mg/kg and prostigmine 0.05/mg/kg. The children were then extubated and transferred to the postanesthesia care unit.
Postoperative pain assessment was done by an independent anesthesiologist who was blinded to the group allocation. Pain assessment was done using the Objective Pain Scale (OPS) scores immediately postoperatively and after 4, 12, and 24/h.
The OPS is a behavioral scale formed of five indicators. The scores range from 0 to 10. Scores between 0 and 3 indicate no or insignificant pain; scores between 4 and 6 indicate moderate pain; and scores between 7 and 10 indicate severe pain [Table 1]. In our study, patients with pain score 4 or more received rescue analgesia. Rescue analgesia was in the form of intravenous proparacetamol 15/mg/kg.
The primary outcome measure was degree of pain according to OPS. The secondary outcome measures were hemodynamic parameters (measured at baseline before induction of general anesthesia, 5/min after induction of general anesthesia in group C and after the RSB in group R, and then every 10/min until the end of surgery), intraoperative fentanyl requirement, and postoperative need for analgesia.
Statistical analysis
Group sample sizes of 25 and 25 achieved 80% power to detect a difference of 3.0 in the pain score between the two group means, with estimated group SDs of 4.3 and 3.0 and a significance level (α) of 0.05000 using a two-sided two-sample t-test. Thirty patients were included in each group to replace any dropout in the sample size.
The statistical analysis was performed using a standard SPSS software package (version 17; SPSS Inc., Chicago, Illinois, USA). Student’s t-test was used to analyze parametric data and were expressed as mean±SD. Categorical variables were analyzed using the χ2-test and were expressed as n (%). Nonparametric data were compared using the Mann–Whitney test and were expressed as median (interquartile range). P values less than 0.05 were considered statistically significant.
| Results | | |
Sixty patients underwent assessment for eligibility, of whom twp patients did not meet the inclusion criteria and another two patients were not successfully approached. Thus, 56 patients were randomized: 27 patients were allocated to group R and 29 patients to group C.
There was no statistically significant difference between the two groups regarding the demographic data (P>0.05; [Table 2].
[Table 3] shows the intraoperative hemodynamic changes. Mean arterial blood pressure and mean HR were lower in group R (MAP: 75.1±7.3/mmHg and HR: 104±6.8/beats/min) than in group C (MAP: 77.45±7.1 and HR: 106±8.1/beats/min), but the differences were clinically nonsignificant (P>0.05).
The total intraoperative fentanyl requirement was significantly lower in group R (22.6±11.9/μg) compared with group C (53.7±6.1/μg). The mean time to first postoperative rescue analgesia was significantly longer in group R (120.8±4.7/min) than in group C (48±3.6/min). The number of rescue doses of analgesia was significantly lower in group R [1 (0–1)] than in group C [3 (2–3)] [Table 4].
Pain scores were significantly lower in group R than in group C, both in the immediate postoperative period and at 24/h postoperatively [Table 5].
| Discussion | | |
The results of this randomized controlled study demonstrate that ultrasound-guided bilateral RSB provides greater intraoperative and postoperative analgesic effect in children undergoing midline abdominal operations in comparison with conventional analgesia. Using real-time imaging, the local anesthetic can be injected accurately under direct vision in the potential space between the rectus muscle and its posterior sheath. This increases the safety of needle injection, especially in young children. This results in blocking of the anterior cutaneous nerves piercing the rectus muscles.
Greater intraoperative analgesia was found in group R as the total intraoperative fentanyl requirement was significantly lower (22.6±11.9/μg) than in group C (53.7±6.1/μg). This resulted in a decrease in fentanyl consumption and thus the adverse effects. This is the same as reported by Finnerty et al. [1]; they reported that RSB decreased opioid consumption and the adverse effects of opioids.
Greater postoperative analgesia was present in group R as the mean time to first postoperative rescue analgesia was 120.8±4.7/min in comparison with that in group C, which was 48±3.6/min. The OPS score was lower in group R than in group C up to 24/h postoperatively. This is in agreement with the results of Bhalla et al. [5], who concluded that ultrasound-guided regional blocks result in higher postoperative pain control in children [5].
Another study by Gurnaney et al. [6], who compared the analgesic efficacy of ultrasound-guided RSB versus local anesthetic infiltration for umbilical hernia repair, reported RSB to be an efficacious method for postoperative pain control [6]. Other studies concluded that ultrasound-guided RSB provides superior intraoperative and postoperative analgesia in comparison with local anesthetic infiltration [7].
Multiple previous studies since the 1980s have discussed the use of regional anesthesia for abdominal field block for inguinal and scrotal procedures with variable postoperative analgesia [8],[9].
One of these studies was conducted by Smith et al. [10]. They reported that in adults the RSB has been shown to improve patient comfort after laparoscopic surgery, suggesting that infiltration by Local anesthetics (LA) in the middle of the rectus muscle, both above and below the anterior wall of the sheath, would result in spread around the anterior cutaneous branches, making the RSB a good alternative to epidural anesthesia for some surgical procedures [10].
The interest in rectus sheath and other anterior abdominal wall nerve blocks in children has increased particularly after the introduction of ultrasound in the practice of pediatric regional anesthesia [11],[12].
A study by Dolan et al. [13] has shown that ultrasound guidance significantly improves the accuracy of RSB when compared with loss-of-resistance techniques.
A retrospective analysis done in 2013 by Breschan et al. [14] studied pediatric patients undergoing hypertrophic pyloric stenosis surgery. They reported that ultrasound-guided RSB with ropivacaine 0.3% at a dose of 0.3/ml/kg above the umbilicus provided sufficient intraoperative and postoperative analgesia [14].
Isaac et al. [15] compared RSB versus local wound infiltration in children undergoing repair of umbilical hernia. Their results suggested that RSB was not better than local wound infiltration for postoperative pain control, using postoperative morphine consumption as a primary outcome.
Another study by Willschke et al. [3] found that bilateral ultrasound-guided RSB with 0.1/ml/kg 0.25% levobupivacaine provides efficient analgesia for umbilical hernia repair.
One limitation of this study is that RSB acts only on the anterior cutaneous branches piercing the rectus sheath while sparing the lateral cutaneous branches. Thus, partial block may result in case of wound in the lateral abdominal wall (e.g. abdominal drain).
Multiple clinical trials are now in progress to examine rectus sheath catheter placement for elective laparotomy. The use of ultrasonography facilitates catheter placement with minimal complications. This block can be used as an alternative to epidural block when the latter is contraindicated.
| Conclusion | | |
Ultrasound-guided bilateral RSB is better than conventional analgesics in providing good intraoperative and postoperative analgesia in pediatric patients undergoing elective midline abdominal procedures.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]
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