Rectus sheath block for postoperative analgesia in patients with mesenteric vascular occlusion undergoing laparotomy: A randomized single-blinded study.

BACKGROUND: Acute mesenteric ischemia is a life-threatening vascular emergency that requires early diagnosis, immediate anticoagulation, and intervention to restore mesenteric blood flow adequately. AIMS: To investigate the effect of rectus sheath block (RSB) for postoperative analgesia in patients with mesenteric vascular occlusion. SETTINGS AND
DESIGN: Forty patients with mesenteric vascular occlusion, American Society of Anesthesiologists physical status I or II or III, scheduled for laparotomy were enrolled in this study. SUBJECTS AND METHODS: Patients were randomized into two groups; control group (C Group) and rectus block group (RB Group). In both groups, general anesthesia was induced fentanyl 1 μg/kg with sleeping dose of propofol and 0.15 mg/kg cisatracurium. Then, anesthesia was maintained with sevoflurane in oxygen 100%. In RB Group, under aseptic condition, RSB guided by ultrasound was performed. Surgery is then continued and intravenous fentanyl patient-controlled analgesia pump started. Postoperative pain, sedation, and opioid side effects were assessed. STATISTICAL ANALYSIS USED: Statistical analysis was done using Statistical Package for Social Sciences (SPSS 19.0, Chicago, IL, USA).
RESULTS: Patients in the RB Group consumed statistically significant less opioid in comparison to control group either intraoperatively or postoperatively. Mean pain scores were statistically significant less in RB Group than in the control group at 2, 4, and 6 h postoperatively. Sedation score, incidence of nausea and vomiting were statistically significant less in the RB Group in comparison to control group. More patients' satisfaction was reported in the RB Group.
CONCLUSIONS: Ultrasound-guided RSB resulted in postoperative reduction of pain scores and opioid consumption compared with general anesthesia alone. Moreover, RSB was associated with better patient satisfaction and less nausea and vomiting.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Acute mesenteric ischemia is a life-threatening vascular emergency that requires early diagnosis and intervention to restore mesenteric blood flow adequately and to prevent bowel necrosis and mortality. Early diagnosis and immediate anticoagulation, aggressive rehydration, antibiotics, as well as effective surgical treatment as needed are essential to improve the clinical outcome.[12] Surgical management includes superior mesenteric artery embolectomy or visceral artery bypass, resection of necrotic bowel tissues.[3]

Postoperative analgesia for critical care patients, who usually need emergency surgery, represents a challenge because of possible association of sepsis, coagulopathy, and instability of hemodynamic variables.[4] In many patients submitted for urgent laparotomy, epidural analgesia is either contraindicated, or there is a risk of decrease in splanchnic blood supply and hypoperfusion of bowel anastomosis with the use of epidural analgesia.[5] In colorectal and urology surgeries, epidural analgesia resulted in excellent pain relief and enhanced recovery after surgery; however, coagulopathy and sepsis are absolute contraindications.[67] Moreover, insertion of epidural catheter requires an expert anesthetist and among those, failure rate range from 20% to 30%.[8]

Rectus sheath block (RSB) using catheters resulted in low pain scores and decrease opioid requirements after major laparotomy.[9] Some authors consider RSB alone as the most effective methods in relieving postoperative pain as well as early recovery following transumbilical gynecological single-incision laparoscopic surgery.[10] Children underwent acute laparoscopic appendicectomy, under general anesthesia with RSB, had significantly reduced pain in the early postoperative period and less hospital stay.[11]

In this study, we assume that RSB might be safe and easy alternative to other analgesic modalities, especially in mesenteric vascular occlusion patients. As those patients are going to undergo major abdominal surgery and need immediate anticoagulation that may preclude or delay use of epidural. We investigate the effect of RSB for postoperative analgesia in patients with mesenteric vascular occlusion undergoing laparotomy in comparison to usual opioid analgesics.

SUBJECTS AND METHODS

After informed consent and Institutional Review Board approval, 40 patients with mesenteric vascular occlusion, American Society of Anesthesiologists physical status I or II or III, scheduled for laparotomy were enrolled in this study. Patients with allergy to amide local anesthetics, epilepsy, neuromuscular disease, or hematological disorders were excluded from this study.

Patients were randomized into two groups; control group (C Group) and rectus block group (RB Group).

In both groups, general anesthesia was induced fentanyl 1 µg/kg with sleeping dose of propofol and 0.15 mg/kg cisatracurium. Then, anesthesia was maintained with sevoflurane in oxygen 100%. Intraoperative monitoring included electrocardiogram (ECG), heart rate, pulse oximetry, noninvasive blood pressure, and end-tidal carbon dioxide concentration. All surgical procedures were performed by the same surgeon.

In RB Group, SonoSite portable ultrasound unit (Philips, ClearVue 350, Bothell, WA, USA) is used to identify sonoanatomy within the rectus sheath. Under aseptic condition, RSB was performed using an insulated 22-gauge regional block needle at a point 2–4 cm lateral to umbilicus on either side. The needle was introduced in the long axis as up and as down as possible. Visualization of fascial split during injection ensures accurate RSB. Following negative aspiration, bupivacaine 0.25% 20 ml is injected between the rectus abdominis muscle and the posterior sheath on either side.

Intraoperative monitoring included ECG, pulse oximetry, noninvasive blood pressure, and end-tidal carbon dioxide concentration. Surgery is then continued and intravenous (i.v.) fentanyl patient controlled analgesia (PCA) pump (Fresenius, Pilot C IS3, France), with a basal infusion of 0.5 µg/kg/h of fentanyl. Additional fentanyl 1 µg/kg is given if there is 10% or more increase in heart rate or blood pressure compared with basal values.

At the end of the procedure, sevoflurane is discontinued, and muscle relaxant is revised. After recovery, PCA is adjusted to give bolus 0.25 µg/kg and lockout interval of 30 min in addition to basal infusion. Visual analog scale (VAS) was used to assess postoperative pain (whereas 1 means no pain and 10 means worst possible pain) at 2 h, 4, 6, 8, 12, 18, and 24 h postoperatively. If VAS more than 3, lockout interval could be decreased to 15 min.

Ondansetron (4 mg i.v.) was administered on the complaint of nausea and/or vomiting. Postoperative sedation was assessed using Ramsay's score (1 - wide awake; 2 - drowsy or dozing intermittently; 3 - mostly sleeping but easily awakened; 4 - asleep, difficulty responding to verbal commands; and 5 - awakened only by shaking).[12] Total intraoperative fentanyl and postoperative consumption in the first 24 h are reported. Adverse events of opioid or rectus block and patient satisfaction are recorded. Primary outcome is postoperative pain. Secondary outcomes are patient satisfaction with analgesia (yes or no), need for additional analgesia, nausea and/or vomiting, pruritus, postoperative ileus, and respiratory depression.

Statistical analysis

Statistical analysis was done using Statistical Package for Social Sciences (SPSS 19.0, Chicago, IL, USA). P =0.05 was considered statistically significant level. Distribution is tested for normality using the Kolmogorov–Smirnov test. Normally distributed data were subjected to parametric tests. Data values were expressed as frequency (%) means ± standard deviation or medians (ranges). The analysis of the data was done to test statistically significant difference between two groups. Student's t-test was used to compare between two groups. Chi-square test was used for qualitative data.

RESULTS

Forty-nine patients with mesenteric vascular occlusion submitted for laparotomy were assessed for eligibility. After randomization, 40 patients only were included in the study [Figure 1]. Two patients were excluded from the study because of hematological disorders. Six patients declined to participate. One patient with epilepsy was excluded from the study. Patients were divided into two groups, twenty patients each; control group (C Group) and rectus block group (RB Group).

Figure 1

Consolidated Standards of Reporting Trails diagram of the study

There was no statistically significant difference with respect to patients’ age, sex, weight, and duration of surgery [Table 1]. The hemodynamic variables including heart rate and mean blood pressure in the two groups were comparable [Figures 2 and 3].

Table 1

Patients’ characteristics data

Figure 2

Perioperative heart rate (beat/min). Data are mean ± standard deviation. *Significant when compared to Group C

Figure 3

Perioperative mean blood pressure (mmHg). Data are mean ± standard deviation. *Significant when compared to Group C

Patients in the RB Group consumed statistically significant less opioid in comparison to control group either intraoperatively or postoperatively [Table 2]. Mean pain scores were statistically significant less in RB Group than in the control group at 2, 4, and 6 h postoperatively [Table 3].

Table 2

Opioid consumption, postoperative complication and patient satisfaction

Table 3

Postoperative pain score

There is no statistically significant difference between the two groups regarding urine retention or pruritus. Sedation score, incidence of nausea and vomiting were statistically significant less in the RB Group in comparison to control group [Tables 2 and 3]. Patients in the RB Group, compared to patients in control group, were more satisfied statistically [Table 2].

DISCUSSION

Early diagnosis of acute mesenteric ischemia is now possible using modern imaging techniques. Most patients have acute superior mesenteric artery occlusion, for whom, explorative laparotomy will be necessary to evaluate the extent and severity of intestinal ischemia.[13] Adequate relief of postoperative pain abdominal surgery with midline incision has been achieved with RSB.[14] RSB has become an easy, safe, and effective technique for control of postoperative pain with long-acting local anesthetic agents and ultrasonic guidance.[15] It has been recently used for postoperative analgesia after gynecological, laparoscopy, umbilical hernia repair, and pediatric surgery.[16171819] However, there are controversies regarding analgesic effects of RSB if incisions are not midline or pain has visceral component.[2021]

In this study, RSB in patients with mesenteric vascular occlusion undergoing laparotomy resulted in statistically significant fewer pain scores in RB Group compared with the control group at 2, 4, and 6 h postoperatively and less 24 h opioid consumption compared with those without block.

In accordance with our results, Bashandy and Elkholy[22] reported significantly lower VAS score in RSB Group compared with general anesthesia group in patients undergoing surgery with midline incision in the early postoperative period. Morphine consumption was lower in RSB Group than GA Group patients not only in postanesthetic care unit but also in the first 2 days postoperatively.

In contrast to our results, Alsaeed et al.[23] investigated the effect of bilateral deposition of bupivacaine 0.25% 0.5 ml/kg within the space between the posterior aspect of the rectus abdominis muscle and its sheath under real-time ultrasonographic guidance. They concluded that it provided sufficient analgesia for umbilical hernia repairs in children postoperatively alone no need for additional analgesia. Explanations for this difference include the different age of patients and nature of pain.

Dolan et al.[24] suggest that use of ultrasound for RSB resulted in improved accuracy and a reduction in potential complications. A fascial plane lying at a variable distance above the anterior layer of the rectus muscle was commonly observed. Blind puncture of this fascial plane may be wrongly interpreted as that of the anterior layer of the rectus sheath muscle.

Gurnaney et al.[25] enrolled 54 patients, scheduled for umbilical hernia repair, in a study to compare the analgesic efficacy of ultrasound-guided RSB and local anesthetic infiltration. They found a statistically significant increase in the perioperative opioid medication consumption in the local anesthetic group.

Isaac et al.[18] found no difference in postoperative opioid use and pain scores when comparing RSB and local anesthetic infiltration. However, they did not use ultrasound. The use of ultrasound guidance provides real-time information about the needle tip location and the local anesthetic delivery to the desired location.[26]

Based on our results, mesenteric vascular occlusion patients should undergo immediate laparotomy which is major abdominal surgery that needs strong analgesics. RSB is a good choice and well tolerated in those patients, especially when compared to conventional opioid analgesics.

One limitation of this study is nonuse of catheter for rectus block as we are worry about the complication of the catheter in patients with mesenteric vascular occlusion. However, no side effect of RB was reported in this study which encourage its use in the future study.

CONCLUSIONS

Ultrasound-guided RSB in patients with mesenteric vascular occlusion undergoing laparotomy resulted in postoperative reduction of pain scores and opioid consumption compared with general anesthesia alone. Moreover, RSB was associated with better patient satisfaction and less nausea and vomiting.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.