An 18-year-old (65 kg) male with severe obstructive sleep apnea (OSA) and no other significant past medical history is scheduled for elective minimally invasive repair of pectus excavatum. Given his OSA, the anesthesia and surgical teams wish to minimize agents that suppress respiratory drive while still adequately controlling his postoperative pain and limiting opioid exposure. Which of the following is most appropriate to add to his postoperative multimodal analgesic regimen?