Levobupivacaine Consumption in Automated Intermittent Bolus in Ultrasound Guided Subparaneural Sciatic Nerve Catheters: A Prospective Double-Blind Randomized Trial

Margaretha B Breebaart,1,2 Jordi Branders,2 Luc Sermeus,3 Sultan Termurziev,2 Helene Camerlynck,2 Lennert Van Putte,1 Marnik Van Putte Minelli,1 Stefan De Hert4 1Faculty of Medicine and Health Sciences, Antwerp University, Wilrijk, Belgium; 2Department of Anesthesia, Antwerp University Hospital, Edegem, Belgium; 3Department of Anesthesiology, St. Luc University Hospital, Brussels, Belgium; 4Department of Anesthesia and Perioperative Medicine, Ghent University Hospital, Ghent, BelgiumCorrespondence: Margaretha B BreebaartDepartment of Anesthesia, Antwerp University Hospital, Wilrijkstraat 10, Edegem, 2650, BelgiumTel +32 486911691Email Margaretha.breebaart@uza.bePurpose: Continuous sciatic nerve blocks have proven benefits for postoperative analgesia after foot surgery. However, the optimal mode of administration remains a point of debate. Ultrasound guided subparaneural injection accelerates onset time and increases duration after a single shot sciatic nerve block. This double blind prospective randomized trial compares the 48-hour local anesthetic (LA) dose consumption of an automated intermittent bolus technique to a continuous infusion regimen in a subparaneural sciatic nerve catheter after hallux valgus surgery.Patients and Methods: Patients scheduled for hallux valgus surgery were randomized to receive either a continuous infusion of levobupivacaine 0.125% at 5mL/h (group A) or an intermittent automated bolus of 9.8 mL every 2 hours with a background of 0.1 mL/h (group B), both with a PCA bolus of 6 mL and lockout of 30 minutes. The 48 hour LA consumption, PCA boluses, Numeric Rating Scale (NRS), satisfaction and return of normal sensation were recorded.Results: Sixteen patients were excluded because of protocol violation or technical problems and 42 patients remained for analysis. The 48 hour ropivacaine consumption was higher in group A (293 ± 60 mL) than group B (257± 33 mL). The median and highest NRS scores and patient satisfaction were not statistically different between groups. Normal sensation returned after 75 ± 22 hours (group A) and 70 ± 17 hours (group B).Conclusion: Programmed bolus administration in subparaneural sciatic nerve catheters reduces LA consumption 48 hours after surgery with equal analgesia and patient satisfaction. Return of sensation is variable and can last more than 75 hours.Keywords: locoregional anesthesia, sciatic nerve block, postoperative pain, local anesthetics, levobupivacaine, orthopedic surgery