Non-Invasive Versus Invasive Blood Pressure Monitoring in Patients During Laparoscopic Bariatric Surgery: a Prospective Method-Comparison Study

Intra-operative blood pressure monitoring in morbidly obese patients using standard non-invasive blood pressure (NIBP) oscillometric technique with upper arm cuffing is often inaccurate. Invasive arterial blood pressure (IABP) monitoring is the gold standard but is not without complications. The purpose of this study was done to assess the degree of agreement between the forearm and upper arm NIBP with the IABP during laparoscopic bariatric surgery. The study was conducted in our university hospital. A total of 36 morbidly obese patients undergoing laparoscopic bariatric surgery were studied. The radial artery was cannulated for IABP monitoring on one upper limb while NIBP monitoring was done on the contralateral upper arm and forearm. The NIBP and its corresponding IABP readings were recorded at selected time points at 10 minutes post-induction; 5, 15, and 30 minutes post-insufflation and 15 minutes postexsufflation. Results: The mean arterial pressure (MAP) has narrower limits of agreement compared to the systolic blood pressure (SBP) and diastolic blood pressure (DBP) for each method of measurement used. Forearm NIBP showed better agreement with IABP compared to upper arm NIBP. Repeated measures ANOVA showed a similar pattern of changes in SBP, DBP, and MAP measured by NIBP and IABP during the surgery. Conclusion: Similar patterns of blood pressure changes were observed with IABP, upper arm, and forearm NIBP measurements at all-time points. The forearm NIBP showed better agreement to IABP as compared to upper arm NIBP and may be adequate to monitor patterns of blood pressure changes during laparoscopic bariatric surgery.