Comparison of intraoperative blood pressure values measured by noninvasive versus invasive methods during normotension, hypertension, and hypotension

Abstract Background and Aims: Monitoring of intraoperative blood pressure (BP) is essential. We aimed to compare BP values simultaneously recorded by invasive and noninvasive methods under general anesthesia (GA) during normotension, hypertension, and hypotension. Mean arterial pressure (MAP) values calculated by the automated technique were also compared to the values obtained using predefined formula. Material and Methods: An observational, prospective study was conducted in 250 adult patients undergoing elective surgeries under GA. Before induction, noninvasive blood pressure (NIBP) was measured in the arm in a supine position using an automated oscillometer. Radial artery in the opposite arm was cannulated. NIBP and arterial BP (ABP) were recorded simultaneously during normotension, hypotension, and hypertension. Results: During normotension and hypertension, systolic BP (SBP) measured by NIBP and ABP were comparable. Diastolic BP (DBP) and MAP during normotension were significantly higher with NIBP (73.65 ± 7.73 vs. 65.69 ± 8.39 and 87.79 ± 8.43 vs. 84.24 ± 8.82, respectively). During hypertension, DBP and MAP were significantly higher with NIBP (90.44 ± 11.61 vs. 78.59 ± 11.09 and 111.67 ± 10.43 vs. 105.63 ± 11.06, respectively). During hypotension, SBP was significantly higher in ABP (91.14 ± 6.90 vs. 86.24 ± 6.06), and DBP and MAP were comparable. Comparison of MAP measured by ABP and NIBP techniques with the MAP calculated using predefined formula in normotension showed significantly higher values with the automated technique. Conclusions: During normotension and hypertension, DBP and MAP showed significantly higher values with the NIBP technique compared to ABP, with comparable SBP values. During hypotension, SBP showed significantly higher values with the ABP technique, with comparable DBP and MAP. MAP obtained using predefined formula and automated method in normotension was significantly higher with the automated technique.