Vital Signs-Integrated Patient-Assisted Intravenous Opioid Analgesia for Post Surgical Pain

To meet the unmet need of better and safer pain relief for acute pain in the post-operative setting, a Vital-signs-integrated Patient-assisted Intravenous opioid Analgesia ("VPIA") Delivery System, with novel and intelligent software algorithms and specialised hardware was developed. In the previous project, the investigators have shown that this system has the potential to increase the safety and patient satisfaction with intravenous opioid analgesia. However, opportunities to develop more robust vital signs monitoring with the goal of ensuring continual and effective analgesia are identified. The primary aim of this proposal is to advance the development of technology (through new features and functionality) and perform clinical evaluation of the VPIA system with a larger sample size to show improvements in patient's satisfaction (pain relief) and robustness of system in terms of vital signs integration. Novel technology using adaptive vital signs controller, integrated with an infusion pump and single finger probe vital signs monitor system will be developed with the aim for commercialisation.

Inclusion Criteria: * American Society of Anaesthesiologist (ASA) physical status I-III; * Age 21-70 years; * Receiving patient controlled analgesia of morphine for postoperative analgesia. Exclusion Criteria: * Allergy to study drug; * With significant respiratory disease and obstructive sleep apnea; * Unwilling to place oxygen saturation and respiratory rate monitoring during study period; * Unable to comprehend the use of patient controlled analgesia; * Obstetric patients.