Development of an Objective Pain Scoring System and its Correlation with Visual Analogue Scale for Evaluation of Postoperative Pain in Patients Undergoing Elective off Pump Coronary Artery Bypass Grafting Surgery: A Prospective Observational Study

Background: One of the most upsetting and frequent side effects after heart surgery is pain. Assessing the presence and intensity of pain, determining who needs assistance, and creating a treatment plan are essential components of effective pain management. Objectives: To formulate an Objective Pain Score (OPS) based on MAP and Heart rate changes, for evaluation of post-operative pain in patients undergoing Elective Off pump Coronary artery bypass grafting surgery (CABG). We also aimed to correlate the OPS with visual analog scale (VAS) score as a tool in pain management. Methods: A hospital based observational study was conducted at Post op Cardiac Surgery Recovery 1 and 2 in Fortis Escorts Heart Institute. The final sample size was 74. So, by rounding off, we decide to take a sample of 75. Consecutive type of non-probability sampling has been done in the study to include 75 patients undergoing Elective Off pump CABG under general anaesthesia at our hospital. Microsoft Excel 2021 was used for graphical depiction, SPSS Version 26.0 was utilized for the majority of the study, and G*Power software version 3.1.7 was used to calculate the sample size. Results: Mean age of study group was 51.1 years with 30.7% cases over the age of 60 years. Out of the total 75 cases undergoing Elective Off pump CABG, 54.7% were females and 45.3% were males. ASA grade II and III was seen in 84% and 16% cases undergoing Elective Off pump CABG. Study showed the mean change in VAS score over the 24-hour post- operative period of cases undergoing Elective Off pump CABG. Our Study showed the mean change in objective pain score over the 24hour post-operative period of cases undergoing Elective Off pump CABG. An excellent correlation (r value >0.8) was observed in majority of the readings between mean VAS and objective pain score, throughout the post-op follow up duration of 24 hours. Conclusion: OPS based on HR and MAP is a simple tool that requires little extra time to apply and causes no discomfort to patients. However, further research would be required to further establish the use of this scale as an objective measure of pain, given our limited sample size and homogeneous patient population.