Propofol used as anaesthesia in surgery had shown small postoperative analgesic benefits over inhalational anaesthetics in some meta-analyses. It was also associated with reduced risk of postoperative nausea and vomiting. Small sample of studies together with high heterogeneity prevented some meta-analyses to confirm propofol's effect for postoperative morphine consumption and other outcomes. Acute Pain Service data bank can provide an alternative way of evaluating postoperative outcomes of propofol anaesthetics through supplying a very large sample size in a more homogeneous setting. Retrospective study comparing propofol and inhalational anaesthetics on postoperative pain matched on patients' demographic and clinical data had been done for liver surgery. Propofol's benefits for postoperative pain and morphine consumption was confirmed but not for adverse effects.

This study plans to analyze the postoperative outcome data from an Acute Pain Service data bank in years 2015-17 to compare the anaesthetics of propofol and inhalational anaesthetics. Comprehensive regression adjustment for confounders are performed using all available patients' demographic, clinical and anaesthetic data. All major surgery types are included. Results will provide postoperative outcome differences between propofol and inhalational anaesthetics for all surgeries and for specific type of surgeries. The large sample bank will provide higher probability for detecting outcome difference between the anaesthetics for all the major surgical types.

Objective: To compare the postoperative outcomes between surgeries anaesthetized with propofol and inhalational anaesthetics in the Acute Pain Service records of Queen Mary Hospital for years 2015-17

Methods:

Retrospective

Data collection

1. Demographic data;
2. Type of surgery;
3. Type of anaesthetic techniques;
4. Postoperative NRS pain scores (Rest and Moving) for Postop Days 1, 2 & 3;
5. Accumulated amount of patient controlled analgesia (PCA) used in Postop Days 1, 2 & 3;
6. Postoperative incidence of nausea, vomitting, dizziness and pruritus.

Inclusion Criteria:

1. Postoperative outcomes from Acute Pain Service data bank between Jan 2015 and Dec 2017 in Queen Mary Hospital would be retrieved;
2. Surgeries with general anaesthesia by either propofol or inhalational anaesthetics.

Exclusion Criteria:

1. Essential data missed;
2. Surgical types with small sample size below 30 for the data collection period.

Surgical and anaesthetic data in years 2015-17 from the Acute Pain Service records of Queen Mary Hospital are included for analysis. Available data are about 6000 surgical cases. Only general anaesthesia by propofol or inhalational anaesthetics are included.