Postoperative Pain Following Coronary Artery Bypass Grafting (CABG)
Conditions
Keywords
CABG, Postoperative pain, Serratus posterior superior plane block, Transversus thoracic plane block, Ultrasound-guided nerve block, Cardiac surgery
Brief summary
The goal of this clinical trial is to learn if combining two ultrasound-guided nerve blocks - one for the front of the chest and one for the side of the chest - works better than standard pain medications alone to treat pain after coronary artery bypass grafting (CABG) surgery. It will also learn about the safety of these nerve blocks. The main questions it aims to answer are: Does the combined nerve block approach lower the amount of opioid pain medication needed in the first 24 hours after surgery? Does the combined nerve block approach lower pain scores at rest and with movement compared to standard care? What medical problems do participants have when receiving the nerve blocks (such as bleeding, infection, or effects from the local anesthetic)? Researchers will compare the combined nerve block group to a standard care group (no nerve blocks) to see if the blocks improve pain control and recovery after heart surgery. Participants will: Be randomly assigned to one of two groups: (1) combined nerve blocks plus standard pain medications, or (2) standard pain medications alone Receive the nerve blocks during surgery while under general anesthesia (if assigned to the block group) Have their pain levels checked regularly using a 0-10 scale for the first 48 hours after surgery Have their breathing, walking time, and opioid medication use monitored during their hospital stay Complete a satisfaction survey about their pain management before leaving the hospital Stay in the hospital for their routine recovery period (typically 5-7 days) with no extra visits required
Detailed description
This is a single-center, patient- and outcome-assessor-blinded, randomized controlled trial conducted at Ain Shams University Hospitals, Cairo, Egypt. Adults aged 18-75 years scheduled for elective isolated CABG via median sternotomy will be enrolled. Eligible participants will be randomized 1:1 to either: Intervention group: Bilateral transversus thoracic plane (TTP) block + bilateral serratus posterior superior (SPSP) block with 0.25% bupivacaine (15 mL per side per block, total 60 mL = 150 mg), performed after induction of general anesthesia and before surgical incision, plus standardized multimodal systemic analgesia. Control group: Standardized multimodal systemic analgesia alone (no nerve blocks). Both groups will receive identical standardized anesthesia (fentanyl, propofol, atracurium, sevoflurane), intraoperative hemodynamic management, and postoperative analgesia (IV paracetamol 1 g q6h scheduled, IV ketorolac 30 mg q8h for 24h then 15 mg q8h, rescue IV morphine via protocolized algorithm and patient-controlled analgesia). The primary endpoint is cumulative 24-hour postoperative opioid consumption (IV morphine milligram equivalents) from extubation. Secondary endpoints include NRS pain scores at rest and with movement at 0, 6, 12, 24, and 48 hours; time to first rescue analgesia; time to first ambulation; respiratory outcomes (time to extubation, PaO₂/FiO₂ ratio, pulmonary complications); hemodynamic stability; ICU and hospital length of stay; patient satisfaction (Likert 1-5); and safety outcomes (block-related complications, LAST, opioid-related adverse events). Sample size: 88 patients (44 per group), calculated for 80% power to detect a 30% reduction in 24-hour opioid consumption (Cohen's d = 0.60) at α = 0.05, with 15% dropout allowance. Randomization will be computer-generated with permuted blocks (sizes 4 and 6), stratified by on-pump versus off-pump status and sex. Allocation concealment via sequentially numbered opaque sealed envelopes. Blinding: patients, outcome assessors, ICU staff, data collectors, statisticians, and non-performing anesthesiologists/surgeons will be blinded; only the performing anesthesiologist will be unblinded. A Data and Safety Monitoring Board will review unblinded safety data at 25% and 50% enrollment. Stopping rules: any death attributable to intervention, ≥2 symptomatic pneumothoraces, or ≥2 severe LAST events. Statistical analysis: ITT as primary population, per-protocol for sensitivity. Primary analysis: ANCOVA adjusting for age, sex, BMI, on-pump status, and intraoperative opioid dose. Missing data handled via multiple imputation (MICE, 20 datasets) with sensitivity analyses.
Interventions
PROCEDURETransversus Thoracic Plane Block
Bilateral ultrasound-guided transversus thoracic plane block with 0.25% bupivacaine (15 mL per side, 30 mL total = 75 mg). Local anesthetic is deposited in the fascial plane between the transversus thoracic muscle and the internal intercostal muscles at the 2nd-4th intercostal space level, blocking the anterior cutaneous branches of T2-T6 intercostal nerves for parasternal analgesia. Performed after induction of general anesthesia using a 22G echogenic needle with in-plane ultrasound guidance.
PROCEDURETransversus Thoracic Plane (TTP) Block
Bilateral ultrasound-guided transversus thoracic plane block with 0.25% bupivacaine (15 mL per side, 30 mL total = 75 mg). Local anesthetic is deposited in the fascial plane between the transversus thoracic muscle and the internal intercostal muscles at the 2nd-4th intercostal space level, blocking the anterior cutaneous branches of T2-T6 intercostal nerves for parasternal analgesia. Performed after induction of general anesthesia using a 22G echogenic needle with in-plane ultrasound guidance.
DRUGConventional Systemic Analgesia
Standardized multimodal systemic analgesia regimen administered to both groups. Intraoperative: fentanyl 5-10 mcg/kg at induction with supplemental 1-2 mcg/kg boluses as needed. Postoperative: IV paracetamol 1 g every 6-8 hours scheduled; IV ketorolac 30 mg every 8 hours for 24 hours then 15 mg every 8 hours; rescue IV morphine 2-3 mg every 5-10 minutes titrated to NRS ≤ 3 for NRS ≥ 4, followed by morphine patient-controlled analgesia (1 mg bolus, 5-minute lockout, 10 mg/hour limit, no background infusion).
DRUGBupivacaine 0.25%
Local anesthetic administered for regional blocks; total dose up to 2.5 mg/kg (maximum 150 mg for patients ≥65 kg, adjusted for lower weights)
Sponsors
Ain Shams University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Masking description
This is a patient- and outcome-assessor-blinded trial. Participants are blinded because all receive identically labelled "study injection" syringes and are under general anesthesia during block performance. Outcome assessors (ICU nurses, data collectors, and statisticians) are blinded to group allocation and access only coded data. The block-performing anesthesiologist is the only unblinded individual. This person is considered both a care provider and an investigator and is therefore excluded from masking for those roles. The block performer is not involved in postoperative care, outcome assessment, or data analysis, per CONSORT 2010 guidelines for interventional trials where complete blinding of the performer is not feasible. All other anesthesiologists, surgeons, and ICU staff are blinded.
Intervention model description
Participants are randomly assigned to one of two treatment groups in a 1:1 ratio. Group 1 receives combined ultrasound-guided serratus posterior superior and transversus thoracic plane blocks plus standardized systemic analgesia. Group 2 receives standardized systemic analgesia alone (no nerve blocks). Both groups undergo identical anesthesia and surgical management. Outcomes are compared between the two parallel groups.
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* Adults aged 18-65 years. * Scheduled for elective, isolated CABG via median sternotomy. * American Society of Anesthesiologists (ASA) physical status II-III. * Ability to understand the study procedures, provide written informed consent, and reliably report pain scores using the NRS.
Exclusion criteria
* Emergency surgery or pre-operative hemodynamics instability. * Known allergies or hypersensitivity to local anesthetics, paracetamol, morphine, or any study medication. * Coagulopathy, uncontrolled bleeding risk, or therapeutic anticoagulation that cannot be safely withheld per institutional guidelines (INR \> 1.5; platelets \< 100 × 10⁹/L at time of block). * Local infection or cellulitis at any planned injection site on the anterior or lateral chest wall. * Pre-existing chronic pain syndrome requiring daily opioid analgesia or known opioid dependence. * Significant cognitive impairment, severe psychiatric disorder, or inability to reliably use pain scales. * History of prior thoracic surgery or major chest wall deformity distorting anatomy or limiting the ultrasound window. * Pregnancy or breastfeeding. * Any other condition judged by the investigator to represent unacceptable risk or preclude study participation. * Patient refusal or withdrawal of consent.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Accumulated from time of tracheal extubation through 48 hours post-extubation | rom time of tracheal extubation until administration of first rescue IV morphine dose for NRS ≥ 4, assessed up to 48 hours post-extubation | Cumulative intravenous morphine milligram equivalents (MME) from tracheal extubation (time 0) to 48 hours post-extubation. All opioid doses administered during this period will be recorded and converted to IV MME using standardized conversion ratios: fentanyl 1 mcg IV = 0.1 mg IV morphine equivalent; hydromorphone 1 mg IV = 5 mg IV morphine equivalent; oxycodone 1 mg oral = 1.5 mg IV morphine equivalent; tramadol 1 mg IV = 0.1 mg IV morphine equivalent. The primary analysis will compare total 48-hour MME between the combined SPSP + TTP block group and the conventional analgesia group. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| NRS pain score at rest | Assessed at extubation (0 h), 6 hours, 12 hours, 24 hours, and 48 hours post-extubation | Numeric Rating Scale (0 = no pain, 10 = worst imaginable pain) assessed at rest at extubation (0 h), 6 h, 12 h, 24 h, and 48 h post-extubation. |
| NRS pain score on movement/coughing | Assessed at extubation (0 h), 6 hours, 12 hours, 24 hours, and 48 hours post-extubation | Numeric Rating Scale (0-10) assessed during deep inspiration, coughing, or turning in bed at 0 h, 6 h, 12 h, 24 h, and 48 h post-extubation. |
| Time to first rescue analgesic | From time of tracheal extubation until administration of first rescue IV morphine dose for NRS ≥ 4, assessed up to 48 hours post-extubation | Minutes from tracheal extubation to first administration of rescue opioid for Numeric Rating Scale ≥ 4 at rest or on patient demand. Rescue protocol: IV morphine 2-3 mg every 5-10 minutes titrated to NRS ≤ 3. Recorded by blinded ICU nursing staff. |
| Time to tracheal extubation | From end of surgery (skin closure) until successful removal of endotracheal tube and spontaneous breathing without ventilatory support, assessed up to 48 hours | Minutes from end of surgery (skin closure) to successful tracheal extubation in the intensive care unit. Successful extubation defined as removal of endotracheal tube with spontaneous breathing maintained for at least 30 minutes without reintubation. |
| Arterial oxygenation (PaO₂/FiO₂ ratio) | Assessed at 6 hours and 24 hours post-extubation | Arterial oxygen tension to inspired oxygen fraction ratio measured at 6 hours and 24 hours post-extubation |
| Incidence of atelectasis | From time of tracheal extubation until hospital discharge or postoperative day 30, whichever occurs first | incidence of atelectasis (radiographic confirmation) |
| Incentive spirometry volume | Assessed at 24 hours and 48 hours post-extubation | Volume achieved with incentive spirometry in millilitres at 24 and 48 hours post-extubation. Assessed by a blinded physiotherapist or nursing staff using standardized technique. |
| Pulmonary complications | From time of tracheal extubation until hospital discharge or postoperative day 30, whichever occurs first | Incidence of atelectasis (radiographic confirmation), pneumonia (clinical and radiographic criteria per CDC definitions), or reintubation occurring during the hospital stay. Composite binary outcome. |
| Intensive care unit length of stay | From ICU admission until ICU discharge, assessed up to 7 days postoperatively | Hours from intensive care unit admission to ICU discharge to the ward. Discharge criteria per institutional protocol: hemodynamic stability without vasopressors, adequate oxygenation on room air or low-flow oxygen, and no active arrhythmias requiring intervention. |
| Hospital length of stay | From date of surgery until date of hospital discharge, assessed up to 30 days postoperatively | Days from surgery (admission) to hospital discharge. Discharge criteria per institutional protocol: ambulatory, pain controlled on oral analgesics, wound healing satisfactory, and no active medical issues requiring inpatient management. |
| Patient satisfaction with pain management | Assessed at 48 hours post-extubation using a 5-point Likert scale | Likert scale 1-5 (1 = very dissatisfied, 2 = dissatisfied, 3 = neutral, 4 = satisfied, 5 = very satisfied) assessing overall satisfaction with postoperative pain management at 48 hours post-extubation. Completed by patient with blinded assessor assistance if needed. |
| Time to first ambulation | From time of tracheal extubation until first documented assisted or unassisted ambulation, assessed up to 7 days postoperatively or until hospital discharge, whichever occurs first | Hours from tracheal extubation to first assisted ambulation greater than 10 metres. Ambulation is defined as standing and walking with or without assistance. Recorded by blinded ICU or ward physiotherapy staff. |
Countries
Egypt
Contacts
PRINCIPAL_INVESTIGATORNasser Elsayed Ebrahim, MD
Ain Shams University
Outcome results
None listed