A preliminary assessment of vital-signs-integrated patient-assisted intravenous opioid analgesia (VPIA) for postsurgical pain

BACKGROUND: We developed a Vital-signs-integrated Patient-assisted Intravenous opioid Analgesia (VPIA) analgesic infusion pump, a closed-loop vital signs monitoring and drug delivery system which embodied in a novel algorithm that took into account patients’ vital signs (oxygen saturation, heart rate). The system aimed to allow responsive titration of personalized pain relief to optimize pain relief and reduce the risk of respiratory depression. Moreover, the system would be important to enable continuous monitoring of patients during delivery of opioid analgesia. METHODS: Nineteen patients who underwent elective gynecological surgery with postoperative patient controlled analgesia (PCA) with morphine were recruited. The subjects were followed up from their admission to the recovery room/ ward for at least 24 h until assessment of patient satisfaction on the VPIA analgesic infusion pump. RESULTS: The primary outcome measure of incidence of oxygen desaturation showed all patients had at least one episode of oxygen desaturation (< 95%) during the study period. Only 6 (31.6%) patients had oxygen desaturation that persisted for more than 5 min. The median percentage time spent during treatment that oxygen saturation fell below 95% was 1.9%. Fourteen (73.7%) out of 19 patients encountered safety pause, due to transient oxygen desaturation or bradycardia. The patients’ median [IQR] pain scores at rest and at movement after post-op 24 h were 0.0 [2.0] and 3.0 [2.0], respectively. The average morphine consumption in the first 24 h was 12.5 ± 7.1 mg. All patients were satisfied with their experience with the VPIA analgesic infusion pump. CONCLUSIONS: The use of VPIA analgesic infusion pump, when integrated with continuous vital signs monitor and variable lockout algorithm, was able to provide pain relief with good patient satisfaction. TRIAL REGISTRATION: This study was registered on clinicaltrials.gov registry (NCT02804022) on 28 Feb 2016.