Journal of Anesthesia and Surgery | Volume 4 | Issue 1 | 2016-11-30

Rectus Sheath Analgesia after Midline Incision Abdominal Surgery: A Comparative Study with Thoracic Epidural Analgesia

Hatem Elmoutaz

Abstract

Background and objectives: Various multimodal analgesia techniques have been tried to provide analgesia for midline abdominal incisions to limit the perioperative use of morphine thus decreasing side effects. Recently, ultrasound-guided rectus sheath blockade for abdominal wall analgesia has been described. We aimed to compare thoracic epidural analgesia and rectus sheath analgesia as regards total morphine consumption in 72 hours postoperative. Patient and methods: This prospective, single-blind and randomized clinical trial was conducted on 60 patients underwent elective abdominal surgery through a midline incision. These patients were randomly allocated into two groups. Epidural analgesia Group (EA) (n = 31): thoracic epidural catheter was activated at the end of surgery with 20 ml of bupivacaine 0.25% plus 2 mcg/ml fentanyl then intermittent doses of 8 ml of the same mixture every hour were given for 72 hrs. Rectus sheath analgesia Group (RSA) (n = 29): received bilateral ultrasound-guided rectus sheath block with catheter insertion that activated at the end of surgery with 20 ml of bupivacaine 0.25% in each site then every 6 hours till 72 hrs. The primary outcome measure in the current study was the interval and total morphine consumption in 72 hours postoperative. Secondary outcome measures included VAS at rest and coughing. Also, morphine-related side effects were measured in the form (ileus, nausea, vomiting, sedation and pruritus). Results: There were a significant lower interval and total morphine consumption in EA group as compared to RSA group, (40.2 11.96 mg vs. 73.4 16.23 mg, P < 0.001) respectively. As regards VAS at rest and coughing, there was no significant difference at all times of measurement between both groups. As regards morphine-related side effects, there was lower non-significant ileus (4 vs. 9), Nausea (5 vs. 7) and sedation (4 vs. 9) in EA compared to RSA group. However, there was higher non-significant vomiting (3 vs. 1) and pruritus (8 vs. 4) in EA group compared to RSA group Conclusion: Ultrasound guided RS block with catheter insertion can be a good adjunctive in postoperative pain management technique for midline abdominal incision when epidural analgesia is not a suitable option.

Keywords: Postoperative analgesia, Rectus sheath analgesia, Midline incision abdominal surgery, Thoracic epidural analgesia

Full text

Abdominal surgeries requiring midline incisions are associated with severe postoperative pain; a substantial component of pain after abdominal surgery is derived from abdominal wall incision [1] . Many multimodal analgesia techniques have been tried to provide adequate analgesia for such incisions attempting to limit the perioperative use of morphine thus decreasing side effects [2] . Several analgesic techniques are used in clinical practice, but none can achieve complete post-operative pain control. A meta-analysis in 2003 supported the common belief amongst many anaesthetists that epidural analgesia provides superior postoperative pain control compared to systemic analgesia [3] . Nevertheless, epidurals are not without risks and the need to use opioids to prevent the sensory regression associated with the use of local anaesthetics alone leads to a greater incidence of side effects [4,5] . Rectus sheath block provides adequate somatic pain relief for abdominal wall structures superficial to the peritoneum. Local anaesthetic instillation within the posterior rectus sheath bilaterally provides intense analgesia for the middle anterior wall from the xiphoid process to the symphysis pubis [6] . Ultrasound (US) guidance is a safe and efficient means to facilitate correct needle place ment and adequate spread of local anesthetic for trun cal blocks [7] . Patient and Methods After local ethical committee approval and patient s informed written consent, this prospective, single-blind and randomized clinical trial was conducted on patients ranged between 18 and 60 years, ASA physical status class I, II and III underwent elective abdominal surgery through a midline incision. Patients with known hypersensitivity to local anesthetics, local infection at the site of block, hypertensive, obese (BMI > 30), any cardiovascular, cerebrovascular, renal, hepatic or muscular disease, patients with coagulation disorders and patients complaining of chronic pain were excluded from the study. Patients were randomly allocated into two groups. An online randomization program was used to generate random number list. Patient randomization numbers were concealed in opaque envelopes that were opened by the study investigator. Epidural analgesia Group (EA): thoracic epidural catheter was activated at the end of surgery with 20 ml of bupivacaine 0.25% plus 2mcg/ml fentanyl then a dose of 8m/hr of the same mixture was given for 72 hrs. Rectus sheath analgesia Group (RSA): received bilateral ultrasound-guided rectus sheath block with catheter insertion that activated at the end of surgery with 20 ml of bupivacaine 0.25% in each site then every 6 hours till 72 hrs. Members of the study group involved in obtaining functional data were blinded to randomization for the period of data acquisition and analysis. One day before surgery all patients were interviewed to explain visual analogue scale (VAS) and routine investigations were fulfilled. On arrival to the operating room, all patients were monitored with ECG, non-invasive blood pressure and pulse oximetry then IV access was established and IV midazolam 0.01 - 0.02 mg/kg was given, after that epidural catheter was inserted at T7-T9 level with no drugs administration except test dose. The epidural block was performed under sterile conditions; the defined insertion point was infiltrated with lidocaine 1%. An 18- gauge epidural needle (Perifix. B.BRAUN Melsungen AG) was utilized for locating the epidural space by the loss of resistance to saline technique. Once the loss of resistance was established, the depth of the needle was marked and recorded using the markings on the needle. A 20-gauge multiple side holes epidural catheter (B. Braun) was inserted 5 cm passed the loss of resistance depth. After securing the catheter in place and establishing negative aspiration, a test dose was given which included a 3 ml of Lidocaine 1% mixed with epinephrine 1: 200,000. General anaesthesia was induced with fentanyl 3mcg/kg, propofol 1 - 3 mg/kg followed by rocuronium 0.6 mg/kg to facilitate endotracheal intubation. Anesthesia was maintained with isoflurane 1 MAC and rocuronium 0.15 mg/kg as a maintenance dose every 30 minutes until the end of the procedure. Ventilation parameters were adjusted as follows: TV = 5 - 8 ml/kg, PEEP 5 cm H2O and respiratory rate = 14/min then it was adjusted to maintain end-tidal CO 2 between 35 - 40 mmHg and peak inspiratory pressure below 30 cm H 2 O. At the end of surgery, in EA group, the epidural catheter was activated with 20 ml of bupivacaine 0.25% plus 2 mcg/ml fentanyl. While, in RSA group a bilateral ultrasound-guided rectus sheath block with a catheter insertion was performed using Logic P5 ultrasound machine (general electric ). The rectus muscle was identified with high frequency (11 MHz) linear ultrasound probe, then under complete asepsis an 18 gauge Tuohy needle was introduced in-plane to the ultrasound probe just below the costal margin at an angle of approximately 45 degrees to the skin. The ultrasound image allows identification of the rectus muscle and hyperechoic twin lines deep to it (posterior rectus sheath and fascia transversalis). Under direct vision, the needle tip is advanced to the desired position, posterior to the rectus muscle and above the underlying rectus sheath. A 20 ml bolus dose of 0.25% bupivacaine was deposited to hydro-dissects the rectus muscle away from the posterior rectus sheath then the catheter was threaded through the Tuohy needle and secured to the skin, and 8 cm of the catheter was inserted into the space. After emerging from anesthesia, all patients were transferred to the post-anesthesia care unit (PACU) for a 2 hours observation period. The patients were discharged from the PACU after fulfilling the discharge criteria based on modified Aldrete score [8] . Postoperative analgesia was provided after surgery by IV Acetaminophen 1 gm and ketorolac 30 mg, then regular oral acetaminophen 1 g four times a day and ketorolac 10 mg three times a day were continued. Postoperative analgesia in EA group was managed with intermittent doses of 8 ml of bupivacaine 0.25 % plus 2 mcg /ml every hour for 72 hours. Postoperative analgesia in RSA group was achieved with 20 ml of bupivacaine 0.25 % in each site then every 6 hours till 72 hours. If Visual analogue pain scale (VAS) 4, rescue analgesia in the form of intravenous morphine based on morphine titration protocol, 3 mg as a bolus dose that could be repeated every 5 minutes with a maximum dose 40 mg/4hours. The criteria to stop morphine titration protocol were satisfactory pain control, Patient became sedated (Ramsay sedation scale > 2), Respiratory rate < 12 / min, Oxygen saturation < 95% or development of serious adverse effects (allergy, severe vomiting, hypotension). If the epidural was ineffective in the recovery room, we re-sited it and started by 20 ml bolus of bupivacaine 0.25 with fentanyl 2 mcg/ml and if the patient still complaining of pain, we started intravenous morphine based on morphine titration protocol. If rectus sheath catheter was ineffective in the recovery room, we re-sited under local anesthesia and if the patient continued to complain pain following re-sitting of the catheter and commenced epidural analgesia. The primary outcome measure in the current study was the interval and 72 hours morphine consumption. Secondary outcome measures included VAS at rest and coughing. Also, morphine-related side effects were measured in the form of ileus (Ileus has been defined as new nausea and vomiting, abdominal distention, and abdominal discomfort with loss of bowel sounds). Nausea and vomiting (0 = no nausea or vomiting, 1 = nausea, 2 = vomiting), pruritus and sedation was assessed on a 5-point sedation Ramsay s score [9] (1, wide awake; 2, drowsy or dozing in termittently; 3, mostly sleeping but easily awakened; 4, asleep, difficulty responding to verbal commands; 5, awakened only by shaking), Over-sedation was defined as having asedation score > 4 combined with a respiratory rate < 8 breath per minute. Analysis of data was done by using SPSS version 16. Quantitative data was presented as mean Standard deviation and was analysed by using unpaired student t-test. Qualitative data was presented as numbers and percentages and was analysed by using Chi-square test. P Value < 0.05 was considered statistically significant. Based on a pilot study with estimation of total morphine consumption at 72 hours (Primary outcome) a sample size of 24 per group was obtained by GPower software version 3.1 using a power of least 80%, the two-sided error of 5% level and effect size was 0.737. We planned to recruit 35 patients per group to minimize any impact of data loss. Results Eighty patients were enrolled in the study. Data from 60 patients, 31 from group EA and 29 from group RSA were included in the final analysis. Eight patients, 5 did not meeting inclusion criteria and 3 who had consented to our protocol the day before surgery, refused to participate in our study on the day of surgery. Five patients were excluded, 3 in group RSA due to failure to perform the block, 2 in EA one due to failure to perform the block and the other due to multiple wet tap. As a result of ICU transfer 3 patients, one in EA group and 2 in RSA exclude from final analysis. Additionally, one patient in EA group due to massive haemorrhage and 3 in RSA due to failure to re-site rectus sheath catheter also were excluded from final analysis. Six patients, 2 from EA group and 4 from RSA group, were proved inoperable on surgical exploration. Though, these patients were included in the final analysis on an intention-to-treat basis (Figure 1). EA, Epidural analgesia - RSA, Rectus sheath analgesia Figure 1: Consort flow diagram. There were a significant lower interval and total morphine consumption in EA group as compared to RSA group (P < 0.001) (Table 1). Table 1: Demographic characteristic and type of surgery. EA (n = 31) RSA (n = 29) p-value Age 48.36 11.73 47.53 9.43 0.76 Weight 79.39 9.47 79.06 7.52 0.88 height 169.03 7.26 168.56 7.30 0.8 Gender(Male: female) 21:10 23:6 0.3 ASA(I:II:III) 7:20:4 3:24:2 0.2 Type of surgery Biliary 11 9 0.33 Partial gastrectomy 8 12 Small intestinal 9 6 Splenectomy 1 3 Pancreatic 2 0 Age, Weight and Height presented as mean SD Gender, ASA status and type of surgery presented as numbers. EA, Epidural analgesia - RSA, Rectus sheath analgesia There was a significant lower interval and total morphine consumption in EA group as compared to RSA group (P < 0.001) (Table 2). Table 2: Interval and total 72 hrs morphine consumption. EA(n = 31) RSA(n = 29) p-value 6hrs postoperative 7.7 2.03 14.6 5.36 < 0.001* 6hrs-12hrs 6.5 2.84 12.8 4.08 < 0.001* 12hrs-24hrs 6.6 2.88 12.63 4.38 < 0.001* 24hrs-48hrs 10.1 4.13 17.93 4.34 < 0.001* 48hrs-72hrs 9.3 4.48 15.43 4.45 < 0.001* Total consumption in the 72 hrs 40.2 11.96 73.4 16.23 < 0.001* Data presented as mean SD, *significant change between both groups EA, Epidural analgesia - RSA, Rectus sheath analgesia As regards VAS at rest and coughing there were higher non-significant values at all times of measurement in group RSA as compared to group EA (figure 2 and 3). EA, Epidural analgesia - RSA, Rectus sheath analgesia Figure 2: Visual analogue scale (VAS) at rest. EA, Epidural analgesia - RSA, Rectus sheath analgesia Figure 3: Visual analogue scale (VAS) at coughing. As regards morphine related side effects, there was lower non significant ileus (4 vs. 9), Nausea (5 vs. 7) and sedation (4 vs. 9) in EA compared to RSA group. However, there was higher non significant vomiting (3 vs. 1) and pruritus (8 vs. 4) in EA group compared to RSA group (Table 3). Table 3: Morphine related side effects. EA (n=31) RSA (n=29) p-value Ileus 4 (13%) 9 (31%) 0.08 Nausea 5 (16%) 7 (24%) 0.43 Vomiting 3 (10%) 1 (3.5%) 0.33 Sedation 4 (3%) 9 (31%) 0.08 Pruritus 8 (26%) 4 (14%) 0.24 Data presented as numbers (percent) EA, Epidural analgesia - RSA, Rectus sheath analgesia Discussion Abdominal surgeries done through midline incisions are associated with severe postoperative pain. Several multimodal analgesia techniques have been tried to provide sufficient analgesia for such incisions aiming at limiting the perioperative use of morphine thus limiting side effects [10] . The extensive origin of the nerves that must be blocked (T5-T12 and L1) to provide analgesia for large midline abdominal incisions is considered a challenging matter. The mid or low thoracic and lumbar epidural analgesia has remained the gold standard for providing good analgesia after abdominal surgery [11] . Unfortunately, epidurals are not suitable for patients with sepsis or coagulopathy. Other regional techniques like rectus sheath (RS) catheters show promise and with the increasing use of ultrasound are useful options for pain relief when epidural anaesthesia cannot be used [12,13] . From a patient safety perspective, RSCs can avoid the rare but potentially catastrophic complications associated with infection in the epidural space. The benefit may have increasing importance when taking into concern the growing use of antiplatelet medications, such as clopidogrel [14] . An early study done by Padmanabhan et al. [15] has assessed the effect of intermittent injection of bupivacaine into rectus sheath space for Patients undergoing midline laparotomy on the postoperative opioid requirement, pain score and peak expiratory flow rate. Patients received either bupivacaine 0.25% or normal saline through surgically placed catheters in the rectus sheath for 48 hours postoperative. No statistically significant differences in postoperative opioid requirement, pain score or PEFR were seen between two groups. The current study demonstrates higher significant 72 hours morphine consumption in RSA group as compared to EA group. This can be explained by: (1) RS block only provides somatic pain relief as opposed to epidural anesthesia that offers both somatic and visceral analgesia; and (2) the administration of opioids in epidural analgesia may decrease the need for intravenous opioids. Our study does not go with Golden et al. [16] who retrospectively reviewed 120 patients underwent open colorectal cancer surgery comparing thoracic epidural analgesia with bilateral rectus sheath catheters. EA was sited between T8 and T11 depending on the dermatome with infusion of 0.125% bupivacaine plus 4 g/ml fentanyl commenced in the recovery room. The RSCs were initially flushed with 10 - 20 ml of 0.25% levobupivacaine 6-hourly for the first 72 hours following surgery. There was no significant difference in the opiate sparing effect of EA over RSC. This difference from our study may be explained as their study was a retrospective non-randomized study with unequal group distribution EA (85) and RSA (24) patients. However, our study demonstrates no significant difference in VAS between both groups which can be explained by compensated increase of morphine in RSA group. Our study goes with Parsons et al. [17] who retrospectively compared between lumber epidural and bilateral ultrasound-guided rectus sheath block in patients underwent a radical cystectomy. The epidural catheter was preferentially sited at the level of (L1-2). Post-operatively, a mixture of bupivacaine 0.125% with fentanyl 4 mcg/ml was infused continuously at 1 8 ml/hr for up to 72 h. Each RSC requires a 20 ml bolus of 0.25% Levo-bupivacaine every 4 - 6 h to ensure a continued analgesic effect. In the first 72 h postoperative, the analgesic effects of the two regional analgesia techniques were equivalent. Study limitation: One limitation of our study was that we evaluated intermittent injection RS catheter; a continuous infusion was not studied, adding adjuvants to LA may improve efficacy and duration of RSB that can be tried in future studies. Conclusion Ultrasound-guided RS block with catheter insertion can be adjunctive in postoperative pain management technique for midline abdominal incision when epidural analgesia is not a suitable option. Trial registration: PACTR201512001386365. Conflict of interest: The authors declare no conflicts of interest. References 1. Wall, P.D., Mezack, R. Pain measurements in persons in pain. Textbook of pain. 4th ed. Edinburgh, UK: Churchill Livingstone, 1999: 409-426. 2. Baig, M.K., Wexner, S.D. Postoperative ileus: a review. (2004) Dis Colon Rec tum 47(4): 516-526. 3. Block, B.M., Liu, S.S., Rowlingson, A.J., et al. Efficacy of postoperative epidural analgesia: a meta-analysis. (2003) JAMA 290(18): 2455-2463. 4. Mogensen, T., Hjortso, N.C., Bigler, D., et al. Unpredictability of regression of analgesia during the continuous postoperative extradural infusion of bupivacaine. (1988) Br J Anaesth 60(5): 515-519. 5. Wheatley, R.G., Schug, S.A., Watson, D. Safety and efficacy of postoperative epidural analgesia. (2001) Br J Anaesth 87(1): 47-61. 6. Webster, K. Ultrasound guided rectus sheath block. (2010) Update Anaesth 26: 12-7. 7. Abrahams, M.S., Horn, J.L., Noles, L.M. Evidence-based medi cine: ultrasound guidance for truncal blocks. (2010) Reg Anesth Pain Med 35(2 Suppl): S36-42. 8. Aldrete, J.A. The post-anesthetic recovery score revisited. (1995) J Clin Anesth 7(1): 89-91. 9. Ramsay, M.A., Savege, T.M., Simpson, B.R., et al. Controlled seda tion with alphaxalone-alphadolone. (1974) Br Med J 2(5920): 656-659. 10. Baig, M.K., Wexner, S.D. Postoperative ileus: a review. (2004) Dis Colon Rec tum 47(4): 516-526. 11. Bashandy, G.M., Elkholy, A.H. Reducing Postoperative Opioid Consumption by Adding an Ultrasound-Guided Rectus Sheath Block to Multimodal Analgesia for Abdominal Cancer Surgery With Midline Incision. (2014) Anesth Pain Med 4(3): e18263. 12. Hermanides, J., Hollmann, M.W., Stevens, M.F., et al. Failed epidural: Causes and management. (2012) Br J Anaesth 109(2):144-154. 13. Crosbie, E.J., Massiah, N.S., Achiampong, J.Y., et al. The surgical rectus sheath block for post-operative analgesia: A modern approach to an established technique. (2012) Eur J Obstet Gynecol Reprod Biol 160(2): 196-200. 14. Christie, I.W., McCabe, S. Major complications of epidural analgesia after surgery: results of a six-year survey. (2007) Anaesthesia 62(4): 335-341. 15. Padmanabhan, J., Rohatgi, A., Niaz, A., et al. Does rectus sheath infusion of bupivacaine reduce postoper ative opioid requirement. (2007) Ann R Coll Surg Engl 89(3): 229-232. 16. Godden, A., Marshall, M., Grice, A., et al. Ultrasonography guided rectus sheath catheters versus epidural analgesia for open colorectal cancer surgery in a single centre. (2013) Ann R Coll Surg Engl 95(8): 591-594. 17. Parsons, B., Aning, J., Daugherty, M., et al. The use of rectus sheath catheters as an analgesic technique for patients undergoing radical cystectomy. (2011) British Journal of Medical and Surgical Urology 4(1): 24-30.