Comparison of Surgical Rectus Sheath Block and Intrathecal Morphine

Study Overview
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Brief Summary
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Pain is the main obstacle in delaying postoperative recovery and leads to prolonged hospital stay. Administration of intrathecal morphine during spinal anaesthesia can provide effective pain control. However, it is associated with significant side effects including nausea, vomiting and itchiness. Also, it is not suitable in all patients, for example, those with morphine allergy, or severe respiratory disease. Surgical rectus sheath block involves injection of local anaesthetic agents into the rectus sheath space before closure of the wound. It has been shown to provide adequate pain control with less systemic side effects. The aim of the study is to evaluate the effectiveness of surgical rectus sheath block and intrathecal morphine in post-Caesarean section pain control.

Detailed Description
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The incidence of Caesarean section is increasing worldwide. Adequate post-operative analgesia is becoming an essential expectation of patients after Caesarean section. The process of recovery will be hindered by suboptimal pain control and eventually it will leads to immobilization and prolonged hospital stay. Spinal anesthesia is usually the mode of anesthesia in pregnancy in view of increase general anesthetic risks. Intrathecal morphine can provide good pain control. However, pruritus can occur in up to 51% of patient, nausea and vomiting in up to 21%. Despite its significant side effects, there is an overall better patient satisfactory over use of intrathecal morphine. Due to its concern on respiratory depression, intrathecal morphine is not recommended in patients with severe respiratory disease, obstructive sleep apnoea or those receiving central nervous system depressants. As a result, there were numerous studies on alleviating the adverse effect and to search for other alternatives. Rectus sheath block aims at blocking the terminal branches of 9th -12th intercostals nerve within the rectus sheath. They form rectus sheath plexus after piercing the posterior aspect of the rectus sheath and then branch into muscular and cutaneous branches. It can be given by anesthetist with or without ultrasound guidance. However, it involved additional time for administration of rectus sheath block and possibility of incorrect placement of catheter leading to ineffective analgesia. On the contrary, surgical rectus sheath block was administrated by surgeon before closure of rectus sheath. It involves injection of local anesthetic in the rectus sheath space before closure of the wound under direct visual control. Surgical rectus sheath block was shown to be effective in postoperative pain control after transverse laparotomy in paediatrics patients. It was shown to be effective in postoperative pain control in Caesarean section without intrathecal morphine. Surgical rectus sheath block may be a simple and safe alternative for intrathecal morphine. However, the evidence on its use in Obstetrics and Gynaecology was sparse and there is no study directly comparing the two different mode of analgesia. The aim of the study is to evaluate the use of surgical rectus sheath and intrathecal morphine for postoperative pain in Caesarean section; and its side effects profile.

Official Title
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Double-blinded Randomized Controlled Study for Comparison of Surgical Rectus Sheath and Intrathecal Morphine for Postoperative Pain Control After Caesarean Section

Conditions
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Pain

Intervention / Treatment
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* Drug: Bupivacaine
* Drug: Morphine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Planned for elective lower segment Caesarean section, using suprapubic transverse incision Willing and able to participate after the study has been explained Those understand either Cantonese, Putonghua or English Exclusion Criteria: Patient with treatment for chronic pain History of narcotic abuse/ recreational drug use Allergy to opioids/ local anesthesia/ paracetamol/ tramadol/ non-steroidal anti-inflammatory drugs Patient with pre-eclampsia

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Rectus sheath block only<br>Patient will be given surgical rectus sheath block postoperatively with 40ml of bupivacaine (2.5mg/mL) and 0.1ml of normal saline will be injected intrathecally at time of spinal anaesthesia. | Drug: Bupivacaine<br>* Surgical rectus sheath block will be performed by injection of 40ml bupivacaine (2.5mg/ml) before closure of rectus sheath during the operation.<br>* Other names: Marcain;|
| Active Comparator: Intrathecal morphine group<br>0.1mg preservative free morphine will be injected intrathecally at time of spinal anesthesia and 40ml of normal saline will be injected as rectus sheath block. | Drug: Morphine<br>* 0.1mg preservative free morphine will be injected intrathecally by anaesthesiologist at the time of spinal anaesthesia.<br>|
| Active Comparator: Both intervention<br>Patient will be given 0.1mg preservative free morphine intrathecally at time of spinal anaesthesia and surgical rectus sheath block with 40ml of bupivacaine (2.5mg/ml). | Drug: Bupivacaine<br>* Surgical rectus sheath block will be performed by injection of 40ml bupivacaine (2.5mg/ml) before closure of rectus sheath during the operation.<br>* Other names: Marcain;Drug: Morphine<br>* 0.1mg preservative free morphine will be injected intrathecally by anaesthesiologist at the time of spinal anaesthesia.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain score | Pain score at rest and movement (elevation of head and shoulder at supine position), using visual analogue scale (0-10) | at 12 hours postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Requirement of oral analgesics | Paracetamol 1gram four times a day on request basis will be prescribed. The number of time requiring paracetamol will be recorded. The need of additional analgesics will be recorded. | within 24hours postoperatively | 
| Time of mobilization | time of starting mobilization, defined as able to get out of bed without assistance | 3days postoperatively | 
| Side effect | side effects including itchiness, nausea/ vomiting, sedation | 3days postoperatively | 
| Pain score | Pain score at rest and movement (elevation of head and shoulder at supine position), using visual analogue scale (0-10), will be accessed at the recovery room after the operation. | Immediate postoperative | 
| Pain score | Pain score at rest and movement (elevation of head and shoulder at supine position), using visual analogue scale (0-10) | 4hours postoperatively | 
| Pain score | Pain score at rest and movement (elevation of head and shoulder at supine position), using visual analogue scale (0-10) | 8hrs postoperatively | 
| Pain score | Pain score at rest and movement (elevation of head and shoulder at supine position), using visual analogue scale (0-10) | 24hrs postoperatively | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Pain, Postoperative pain control, Rectus sheath block, Intrathecal morphine, Caesarean section