PURPOSE: The purpose of this study was to compare the success rate, measurement duration and the accuracy of inflationary non-invasive blood pressure (iNIBP, Nihon Koden Corp, Tokyo, Japan) during general anesthesia between the subjects with sinus rhythm (SR) and atrial fibrillation (AF) against invasive arterial pressure (IAP). METHODS: iNIBP was determined every 5 min and IAP was continuously monitored in 30 subjects with sinus rhythm and 30 subjects with atrial fibrillation. The outcomes of this study were the success rate, the measurement duration of iNIBP and the accuracy of iNIBP in reference to IAP and 5 pair of data from each subject. The accuracy was assessed with concordance correlation coefficient and Bland-Altman method. RESULTS: The success rate of iNIBP was 45% and 59% (p <
0.01) with AF and SR, respectively. Measurement duration of iNIBP was not different between AF and SR group. The Lin concordance correlation coefficient of mean blood pressure of iNIBP against IAP of SR group and AF group was 0.83 and 0.77, respectively. The mean bias (SD) of mean blood pressure of iNIBP against IAP of SR group and AF group was 5.8 (8.9) mmHg and 7.1 (11.5) mmHg, respectively. The precision was significantly wider in AF group. CONCLUSION: Presence of AF decreased the incidence of successful determination of blood pressure during cuff inflation. The accuracy of mean blood pressure determination was not considerably affected except for the wider limits of agreement.