Cardiac Surgery: Perioperative Analgesia

Anesthesia for cardiac surgery has traditionally relied on high-dose opioids to mitigate the body’s sympathetic response to surgery [1]. However, recent studies have suggested that opioids extend postoperative intubation, resulting in increased morbidity [1]. Moreover, in-hospital exposure to opioids have been linked to increased dependency [1]. Regional cardiac analgesia techniques, also known as fast-track cardiac anesthesia (FTCA), have emerged as a promising alternative to traditional IV opioids for controlling perioperative pain [2]. 

The use of FTCA techniques in cardiac surgery dates back to 1954 when one of the first heart surgeries was performed under thoracic epidural analgesia (TEA) [3]. Advantages of TEA include decreased incidence of adverse cardiovascular events (e.g. stroke and myocardial ischemia), fewer respiratory complications, decreased risk of renal failure, lower infection rates, and earlier hospital discharge [3]. Additionally, TEA can continuously provide analgesia throughout the perioperative period [3]. Several clinical trials have confirmed the safety of TEA, but concerns remain over potential complications, such as spinal cord compression caused by a hematoma or abscess [3,4].  A meta-analysis examining the difference in rates of mortality and myocardial infarction after cardiac surgery for patients receiving TEA with general anesthesia, intrathecal analgesia with general anesthesia, or general anesthesia alone was published in 2004 [5]. The study examined 1,178 patients and concluded that there was no difference in rates of mortality or myocardial infarction in those who receive TEA versus general anesthesia only [5]. However, patients who received TEA were found to have decreased pulmonary complications, fewer cardiac dysrhythmias, and reduced pain scores [5]. A follow-up meta-analysis completed in 2011 yielded results consistent with the previous study [4]. 

Another well-studied FTCA technique is the paravertebral block [6]. Paravertebral block of the spinal nerve roots provides similar analgesia to TEA without the risk of hypotension or hematoma [6]. Additional benefits of paravertebral blocks include reduced opioid exposure and risk of perioperative myocardial infarction [1]. Other FTCA techniques that have been studied include parasternal, pectoral, and erector spinae plane blocks [1]. These techniques require further investigation but show a potential to further reduce the risk of adverse complications [1]. 

Pain following cardiac surgery may be intense, typically peaking on the first postoperative day [2]. Inadequate analgesia during the postoperative period can result in many adverse hemodynamic, metabolic, immunologic, and hemostatic alterations [2]. Techniques available for postoperative analgesia include local anesthetic infiltration via catheters placed at the incision site, nerve blocks, IV opioids, nonsteroidal anti-inflammatory drugs, cyclooxygenase inhibitors, and alpha-adrenergic agonists [2]. The American Society of Anesthesiologists Task Force on Acute Pain Management in the Perioperative Setting recommends a multimodal analgesia approach to provide superior analgesic efficacy with fewer adverse effects [2]. 

In an attempt to reduce postsurgical pain, researchers have also investigated the effect of remifentanil infusion during cardiac surgery on postoperative pain scores [7]. Remifentanil infusion has been associated with reduced postoperative pain, allowing patients to avoid the need for a nerve block [7]. Buprenorphine infusion has also been shown to reduce pain immediately following cardiac surgery [7]. 

References 

1. Caruso, T., Lawrence, K., & Tsui, B. (2019). Regional anesthesia for cardiac surgery. Current Opinion in Anaesthesiology, 32(5), 674-682. doi:10.1097/aco.0000000000000769 

2. Chaney, M. (2006). Intrathecal and Epidural Anesthesia and Analgesia for Cardiac Surgery. Anesthesia & Analgesia, 102(1), 45-64. doi:10.1213/01.ane.0000183650.16038.f6 

3. Liu, H., Emelife, P., Prabhakar, A. et al. (2019). Regional anesthesia considerations for cardiac surgery. Best Practice & Research Clinical Anaesthesiology, 33(4), 387-406. doi:10.1016/j.bpa.2019.07.008 

4. Svircevic, V., Nierich, A., Moons, K. et al. (2009). Fast-Track Anesthesia and Cardiac Surgery: A Retrospective Cohort Study of 7989 Patients. Anesthesia & Analgesia, 108(3), 727-733. doi:10.1213/ane.0b013e318193c423 

5. Liu, S., Block, B., & Wu, C. (2004). Effects of Perioperative Central Neuraxial Analgesia on Outcome after Coronary Artery Bypass Surgery. Anesthesiology, 101(1), 153-161. doi:10.1097/00000542-200407000-00024 

6. Bigeleisen, P., & Goehner, N. (2015). Novel approaches in pain management in cardiac surgery. Current Opinion in Anaesthesiology, 28(1), 89-94. doi:10.1097/aco.0000000000000147 

7. Anwar, S., & O’ Brien, B. (2021). The Impact of Remifentanil Infusion During Cardiac Surgery on the Prevalence of Persistent Postsurgical Pain. Journal of Cardiothoracic and Vascular Anesthesia, 35(2), 467-469. doi:10.1053/j.jvca.2020.09.131