Assessment of Total Ropivacaine Concentration in Blood after Bilateral Pecto-Intercostal Fascial Block Combined with Rectus Sheath Block in Cardiac Surgery Patients

Abstract

Objectives: Pecto-intercostal fascial block (PIFB) and rectus sheath block (RSB) have been combined to offer better analgesia for cardiac surgery patients, but safety of the analgesic protocol with a large volume of ropivacaine is uncertain. Methods: This is a prospective observational study at Peking University People's Hospital to investigate the pharmacokinetic profile of ropivacaine after combined regional blocks. Patients undergoing elective cardiac surgery by a median sternotomy were enrolled to receive bilateral PIFB and RSB with 70 mL 0.3% ropivacaine (total dose 210 mg). Blood was sampled at 5, 10, 15, 30, 60, 90 and 120 mins after blocks. Total blood concentration of ropivacaine for patients were measured. Results: Ten patients were enrolled and analyzed. The peak total ropivacaine concentration varied from 0.67 to 2.42 µg/mL. Time to reach the peak values mainly located between 10 and 30 mins after the performance. No patients had ropivacaine concentration values above toxic threshold (4.3 µg/mL), and there were no systemic toxicity symptoms during the perioperative period. Conclusions: PIFB combined with RSB in a general injection of 70 mL 0.3% ropivacaine does not give rise to toxic levels, and it is an effective and safe analgesic protocol for cardiac surgery patients.