Dexamethasone versus dexmedetomidine as adjuncts for parasternal block in cardiac surgery: a retrospective comparative study

Postoperative pain following cardiac surgery via sternotomy is typically severe, often impairing respiratory mechanics and delaying extubation. The use of parasternal blocks in combination with adjuvants, such as dexamethasone or dexmedetomidine, has shown potential in enhancing analgesia, facilitating earlier extubation, and reducing intensive care unit (ICU) length of stay. In this retrospective comparative study, medical records of patients were reviewed. At the conclusion of surgery, patients had received a bilateral superficial ultrasound-guided parasternal block (US-PSB) using a 30 mL dose (15 mL per side) of 0.375% levobupivacaine (112.5 mg total). The study cohort included 347 patients, categorized into two groups based on clinical administration: one group received 0.1 mg/kg dexamethasone (222) and the other group received 1 mcg/kg dexmedetomidine (125). The purpose of the study was to evaluate whether there is a difference between the two adjuvants administered in the block in terms of analgesia and extubation time. No statistically significant differences in weaning time from the ventilator or self-reported pain scores were observed between the two groups. Notably, 45.8% of patients reported no pain (Visual Analog Scale [VAS] score 0) at the 4-hour assessment following surgery, which increased to 97.1% at the 12-hour assessment. Both dexamethasone and dexmedetomidine showed comparable outcomes in terms of analgesia, with no significant differences observed between the groups up to 24 hours postoperatively, without significant differences in weaning time. There were no statistically significant differences in extubation time or pain levels between the dexamethasone and dexmedetomidine groups. Both agents showed comparable outcomes as adjuvants, but their absolute effectiveness cannot be concluded due to the absence of a control group for parasternal block in cardiac surgery.