[Oral therapy algorithm for the treatment of postoperative pain. A prospective observational study]

Abstract

Background: Postoperative pain continues to be undermanaged, at least in part, due to inadequate organization and lack of use of opioids. Especially patients who do not receive consultation from an acute pain service and are therefore not eligible to receive regional anesthesia techniques or patient-controlled devices suffer from severe pain after surgery. The aim of the present prospective observational study was to assess the efficacy and feasibility of an analgesia algorithm for this subgroup of patients.

Methods: An oral opioid concept including controlled-release (cr) oxycodone, immediate-release (ir) hydromorphone and a non-opioid analgesic was implemented at three different departments at the University Clinic of Muenster, Germany. Briefly, cr-oxycodon was administered preoperatively to patients undergoing ear nose and throat (ENT), general or elective trauma surgery on the day of surgery and every 12 h for a maximum of 4 days postoperatively. Inadequately managed pain above 3 on a visual analog scale (VAS 0-10) at rest and above 5 during movement was treated with ir-hydromorphone on patient request. After written informed consent, patients were assessed prospectively for up to 5 days perioperatively using a standardized questionnaire preoperatively, for 4 days postoperatively as well as 6 and 12 months after surgery.

Results: A total of 275 patients were included in the present prospective observational study: (ENT surgery: 163, trauma surgery 82 and general surgery 30). Median resting and evoked numeric rating scale (NRS) pain scores were equal or less than 3 and 5, respectively. Less patients received cr-oxycodone after ENT and general surgery compared to trauma surgery (p < 0.001). Constipation was more frequent after general and trauma surgery compared to ENT surgery. Vomiting decreased from 20 %-30 % on the day of surgery to 10 % or less regardless of the type of operation. No severe adverse events were observed. Additionally, patients with an increased depression score before surgery reported greater immediate postoperative pain than non-depressed patients. Of the patients 11 (15.7 %) and 7 (14.9 %) complained about persistent postoperative pain 6 and 12 months after surgery, respectively and these patients had increased acute pain ratings during the first postoperative days.

Conclusions: The present study has demonstrated that the implementation of an oral opioid algorithm for patients without patient-controlled intravenous or regional analgesia is effective and feasible on surgical wards. Patients who underwent trauma surgery needed more cr-oxycodone. Side effects were similar regardless of the operation with the exception of obstipation which was more frequent after trauma and general surgery compared to ENT surgery.