The efficacy of continuous peripheral blocks after cardiothoracic surgery as evaluated by opioid use, pain, and recovery

Abstract: Pain after cardiothoracic surgery is most intense the first postoperative days and for the most part mild to moderate. International guidelines recommend a multimodal analgesic strategy that includes local anesthetics for peripheral nerve blocks or local wound infiltration. However, for cardiothoracic surgery, there is a lack of evidence on (1) the best peripheral nerve block for minimally invasive and open procedures, (2) whether continuous nerve blocks are superior to single-shot blocks, and (3) if and what type of local anesthetic adjuncts should be used. Importantly, (4) the evaluation of the blocks should extend beyond the first 24 hours and include patient recorded outcome measures (PROMs). This thesis studied the efficacy of a continuous extrapleural block as part of a multimodal analgesic strategy after video-assisted thoracic surgery (VATS), whether the adjuncts sufentanil and adrenaline improved the analgesic effect of levobupivacaine in a continuous extrapleural block after VATS, and whether a continuous bilateral parasternal block with lidocaine reduced opioid requirement and improved recovery after sternotomy. In addition, the 3-month recovery after sternotomy was evaluated by means of an eHealth platform for repetitive Quality of Recovery (QoR)-15 scores and pain assessments. Study I showed that a continuous multiple-day infusion of levobupivacaine through a surgeon-inserted extrapleural catheter was a valid and safe part of a multimodal analgesic regimen after VATS. It also showed that VATS lobectomy was more painful than wedge resection. In Study II, levobupivacaine at 2.7 mg ml-1 and levobupivacaine at 1.25 mg ml-1 with the adjuncts sufentanil and adrenaline neither differed in 48- or 72-hour opioid requirement nor pain when infused extrapleurally at 5 ml.h-1 after VATS. Cumulative morphine doses of both treatment groups were low, and pain was overall mild. Infusion of 5 ml.h-1 levobupivacaine at 2.7 mg ml-1 (highest recommended daily dose) did not result in toxic serum concentrations, but it possibly resulted in superior analgesia in movement and improved recovery according to QoR-15 at 3 weeks postoperatively. Study III showed a postoperative 72-hour continuous bilateral parasternal block with lidocaine decreased morphine requirement with 65%. However, despite the well-controlled pain and the low 72-hour morphine dose, no improvement of recovery according to QoR-15 was seen. Neither did the systemic presence of lidocaine result in a decreased inflammatory response. Study IV showed an acceptable recovery as assessed by QoR-15 at 2 weeks after sternotomy for open heart surgery. The use of an eHealth platform for repetitive questionnaires was feasible. Age and the extent of surgery affected the questionnaire’s response rate.