Perioperative pain management in cardiac surgery: A systematic review

BACKGROUND: Every year, more than 1.5 million patients, who undergo cardiac surgery worldwide, are exposed to a series of factors that can trigger acute postoperative pain associated with hemodynamic instability, respiratory complications, and psychological disorders. Through an evaluation of literature data about postoperative pain in cardiac surgery we define unmet needs and potential objectives for future research on this often-underestimated problem. METHODS: Following PRISMA Guidelines, a systematic literature search was carried out by two independent researchers on Scopus, CINAHL, the Cochrane Library, and PubMed using the key words: (perioperative OR postoperative) analgesia AND "cardiac surgery." Papers concerning children, or published prior to 2000, were considered ineligible, as well as abstracts, animal studies, and studies written in languages other than English. RESULTS: Fifty-four papers were selected and subsequently divided into two main categories: systemic analgesic drugs and regional anesthesia techniques. CONCLUSIONS: Over the past 17 years, opioids are still the most extensively used therapy, whereas we found only few trials investigating other drugs (e.g. paracetamol). Regional anesthesia techniques, especially thoracic epidural analgesia and intrathecal morphine administration, can effectively treat pain, but have not yet showed any significant impact on major clinical outcomes, with several concerns related to their potential complications. To date multimodal analgesia with implementation of regional analgesia seems to be the best choice. In the future, better-designed studies should consider other drugs stratifying groups according to comorbidities and risk factors, as well as using standardized units of measurement.