Pain after cardiac surgery can be moderate to severe with incisions to the sternum and lower extremities, and also the placement of chest tubes. Postoperative pain may contribute to delirium, stress, myocardial oxygen demand supply imbalance, etc. Traditionally postoperative pain management after cardiac surgery has been based on opiate analgesics. However, opiates have many deleterious side effects including nausea/vomiting, ileus, bladder dysfunction, and respiratory depression, which substantially influence patient recovery and may delay discharge after surgery.

The current study is designed to evaluate if an opiate sparing multimodal regimen of tylenol, gabapentin, ketamine, lidocaine and dexmedetomidine provided better analgesic effect (pain score, postoperative PCA opioid dose), less side effects (PONV) and improved cardiac surgery outcome (delirium, a-fib, AKI, dysglycemia) compared to a traditional fentanyl and hydromorphine regimen after cardiac surgery. Additionally, it aims to investigate if the benefit of multimodal regimen is achieved by combination of all drugs or all drugs except dexmedetomodine by introducing third group of study patients who will be randomized to all interventions except saline placebo instead of dexmedetomodine infusion.

Inclusion Criteria:

• ASA II-III Grade
• BMI 18-31kg/m2
• Adult patients presenting for on-pump cardiac surgery through median sternotomy

Exclusion Criteria:

• Cardiac surgery without sternotomy
• emergency surgery
• h/o allergy to any of the medications in the research protocol
• hepatic disease with elevated liver enzymes (preoperative SGPT and SGOT elevated to 1.5 times maximum normal value)
• pregnancy
• unable to give consent
• preoperative mental disorders