CASE 8--2015. Paravertebral Catheter-Based Strategy for Primary Analgesia After Minimally Invasive Cardiac Surgery.

Abstract

ORT-ACCESS MINIMALLY INVASIVE cardiac surgery (PACS) has potential advantages when compared with traditional sternotomy techniques. These include smaller surgical incision, reduced trauma and blood loss, and shorter length of hospital stay. 1,2 Typically, PACS procedures are performed through a right anterior minithoracotomy or hemisternotomy, and postoperative pain commonly is managed primarily using intravenous analgesics, usually with an on-demand opioid or opioid-based patient-controlled analgesia (PCA). When an opioid is chosen as the primary strategy, particularly an intravenous PCA, benefits include ease of use, availability, and improved patient satisfaction, compared with on-demand pain treatment. Common adverse effects to opioidbased strategies include respiratory depression, delirium, and gastrointestinal dysfunction, which substantially can inhibit postoperative recovery and potentially cause harm to the aging and comorbid population that represents many cardiac surgery patients. In addition, minithoracotomy incisions used during PACS procedures also involve an increased risk of chronic pain, which is not prevented or reduced by an opioid-only strategy. 2–4 Analgesic strategies that reduce opioid consumption and improve long-term outcome after PACS, including regional or neuraxial anesthetic techniques, are desirable to reduce this complication and improve outcomes from PACS procedures. For thoracic surgery patients, regional analgesia delivered through thoracic paravertebral (PV) or epidural catheters provides high-quality analgesia for post-thoracotomy pain and is associated with reduced overall complication rates relative to parenteral opioids. 5–14 Published studies indicate that thoracic PV and epidural-based analgesia delivery of continuous local anesthetic infusions are approximately of equal value for pain control, but PV catheters are associated with fewer side effects, including hypotension. 15–17 The advantages of regional techniques involving the neuraxis always must be contrasted against their associated risk of epidural hematoma, particularly related to anticoagulation used during cardiopulmonary bypass (CPB). To avoid the risk of epidural hematoma, an alternate approach to neuraxial regional analgesia includes PV catheter placement. Although the usefulness of PV catheters have been confirmed for post-lung resection thoracotomy analgesia, their value for PACS patients is unclear. Here, the clinical course of 3 cardiac surgery patients undergoing PACS with PV catheters inserted for primary analgesia is described. These examples are reviewed in the context of existing literature and also serve to highlight the challenges of postoperative analgesia for PACS patients.