A 7-year-old girl, born with microtia (grade III), undergoes an external ear reconstructive surgery. The cartilage for the reconstruction is harvested from 5th to 7th costal cartilages of the right side. Her past medical history is significant for developmental delay and moderate obstructive sleep apnea. For intraoperative pain management, IV ibuprofen and acetaminophen is used. After an uneventful intraoperative period, the patient is transferred to the postoperative area. Two hours later, she begins to experience significant pain over the donor site. She is crying inconsolably and is unable to move. The pain is worsened with deep inspiration. The family has a history of substance use disorder and is very concerned about the use of opioids. Which of the following is most likely the best approach for managing pain in this child?