Patient Re-education vs. Background Morphine to IV-PCA in Patient With Unsatisfactory Analgesia Post Laparotomy

Comparing Effectiveness of Post-operative Analgesia Between Patient Re-education and the Additional of a Basal Morphine Infusion to IV-PCA Morphine in Patients With Unsatisfactory Analgesia After Laparotomy

The purpose of this study is to improve IV-Patient Controlled Analgesia (IV-PCA) technique for postoperative analgesia. Investigators are comparing between patient re-education and the background morphine infusion among patients who fail to achieve satisfactory analgesia using IV-PCA Morphine after laparotomy.

In this study, investigators have a second inclusion criteria for subject recruitment. For subjects who meet this criteria meaning their dynamic pain (when blowing incentive spirometer) is ≥ 4/10 after starting on IV-PCA Morphine will be randomized in to 2 groups. One group will receive patient re--education with an additional background morphine infusion and the other group will receive re--education only.

The second highlight for this study is regarding the background morphine calculation. The background morphine is calculated according to this formula:

Total morphine requirement in the first 24 hours post surgery (mg) = 100 - Age (year) So, the background morphine infusion will be calculated based on subject's age and half of their 24 hours requirement will be infused over 24 hours.

This formula was published by Pamela Macintyre in her paper titled " Age is the Best Predictor of Postoperative Morphine Requirement".

Inclusion Criteria:

• American Society of Anesthesiologists (ASA)Physical Status Classification Class I and II
• Elective laparotomy
• able to understand either malaysia, mandarin, english language or local dialect
• patient with dynamic pain score 4/10 and more within the first 4-hour after initiation of IV-PCA

Exclusion Criteria:

• patient refusal
• laparotomy with pfannenstiel incision
• patients with a history of allergy to opioids
• patients who required post-operative ventilation support
• patients ASA III and above
• patients unable to use PCA due to insufficient comprehension
• morbid obesity/ obstructive sleep apnea
• chronic opioid or alcohol abuse