A randomised controlled comparison of serratus anterior plane, pectoral nerves and intercostal nerve block for post-thoracotomy analgesia in adult cardiac surgery

Abstract

Background and aims: Enhanced recovery after cardiac surgery is centred around multimodal analgesia which is becoming increasingly feasible with the advent of safer regional analgesic techniques such as fascial plane blocks. We designed this prospective, single-blind, randomised controlled study to compare the efficacy of serratus anterior plane block (SAPB), pectoral nerves (Pecs) II block, and intercostal nerve block (ICNB) for post-thoracotomy analgesia in cardiac surgery.

Methods: 100 adults posted for cardiac surgery through a thoracotomy were randomly allocated to one of the three groups: SAPB, Pecs II or, ICNB wherein the patients received 2.5 mg/kg of 0.5% ropivacaine for ultrasound-guided block after completion of surgery. Postoperatively, intravenous (IV) paracetamol was used for multimodal and fentanyl was employed as rescue analgesia. Visual analogue scale (VAS) was evaluated at 2, 4, 6, 8, 10 and 12 hours post-extubation.

Results: The early mean VAS scores at 2, 4 and 6 hours were comparable in the 3 groups. The late mean VAS (8, 10 and 12 hours) was significantly lower in the SAPB and Pecs II group compared with that of the ICNB group (P value <0.05). The cumulative rescue fentanyl dose was significantly higher in ICNB group compared to SAPB and Pecs II group (P value <0.001). The SAPB group had the highest time to 1^st rescue analgesic requirement in contrast to the other groups.

Conclusion: SAPB and Pecs II blocks are simple single-shot effective alternatives to ICNB with a prolonged analgesic duration following thoracotomy and can potentially enhance pain-free recovery after cardiac surgery.

Keywords: Adult cardiac surgery; intercostal nerve block; pectoral nerve block; postoperative pain; serratus anterior plane block; thoracotomy.

Figure 1

CONSORT flow diagram

Figure 2

Depiction of the SAPB sonoanatomy with the needle directed (at the level of the fifth rib) toward the optimal plane for local anaesthetic deposition below the serratus anterior muscle (a); Ultra-sonographic image outlining the Pectoralis major and minor muscles (b); Pecs II block with the needle drug injection hydro-dissecting the plane between the pectoral muscles (c); Sonoanatomy of the intercostal musculature and adjacent ribs for administering ICNB (d). LA: Local anaesthetic; LD: Latissimus dorsi; TM: Teres Major; P Major: Pectoralis major; P Minor: Pectoralis minor

Figure 3

VAS trends upto 12 h post-extubation (a); Number of patients demonstrating a VAS >4 in the three groups at different time points (b)