Regional Analgesia for Cardiac Surgery Part 1. Current status of neuraxial and paravertebral blocks for adult cardiac surgery.

Cardiac surgeries are known to produce moderate to severe pain. Pain management has traditionally been based on intravenous opioids. Poorly controlled pain can result in increased incidence of respiratory complications such as atelectasis and pneumonia leading to prolonged intubation and intensive care unit length of stay and subsequent prolonged hospital stay. Adequate perioperative analgesia improves hemodynamics and immunologic responses, which would result in better outcomes after cardiac surgery. Opioid sparing "Enhanced Recovery After Surgery" protocols are increasingly being incorporated into cardiac surgeries. This will reduce opioid requirements and opioid-related side effects and facilitate fast-tracking of patients. Regional analgesia can be provided by neuraxial blocks, fascial plane blocks, peripheral nerve blocks, or simply by the infiltration of the wound with local anesthetics for cardiac surgery. Neuraxial analgesia is provided through epidural, spinal, and paravertebral routes. Though they are being replaced by peripheral fascial plane blocks, epidural and spinal analgesia are still being used in some centers. In this article, neuraxial forms of analgesia are focused. We sought to review epidural analgesia and its impact in suppressing hemodynamic stress response, reducing pulmonary complications, and development of chronic pain. The relationship between intraoperative heparinization and potential neuraxial hematoma is discussed. Other neuraxial options such as spinal and paravertebral analgesia and their usefulness, benefits, and limitations are also reviewed.

Regional Analgesia for Cardiac Surgery. Part 2: Peripheral Regional Analgesia for Cardiac Surgery.

The introduction of regional analgesia in the past decades have revolutionized postoperative pain management for various types of surgery, particularly orthopedic surgery. Nowadays, they are being constantly introduced into other types of surgeries including cardiac surgeries. Neuraxial and paravertebral plexus blocks for cardiac surgery are considered as deep blocks and have the risk of hematoma formation in the setting of anticoagulation associated with cardiac surgeries. Moreover, hemodynamic compromise resulting from sympathectomy in patients with limited cardiac reserve further limits the use of neuraxial techniques. A multitude of fascial plane blocks involving chest wall have been developed, which have been shown the potential to be included in the regional analgesia armamentarium for cardiac surgery. In myofascial plane blocks, the local anesthetic spreads passively and targets the intermediate and terminal branches of intercostal nerves. They are useful as important adjuncts for providing analgesia and are likely to be included in "Enhanced Recovery after Cardiac Surgery (ERACS)" protocols. There are several small studies and case reports that have shown efficacy of the regional blocks in reducing opioid requirements and improving patient satisfaction. This review article discusses the anatomy of various fascial plane blocks, mechanism of their efficacy, and available evidence on outcomes after cardiac surgery.