A Comparison of invasive arterial blood pressure measurement with oscillometric non-invasive blood pressure measurement in patients with sepsis

Background: Multiple studies had investigated the discrepancies of different blood pressure monitoring techniques in critical patients, but it remained controversial in patients with sepsis. This study aimed to compare non-invasive oscillometric blood pressure (NIBP) measurement with invasive arterial blood pressure (IBP) measurement in patients with sepsis. Methods We conducted a retrospective study to evaluate the agreement between IBP and NIBP using the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Paired blood pressure measurements of mean arterial pressure (MAP), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were compared using Bland-Altman analysis and paired Student’s t-test. We also focus on the effect of NE on the agreement between the two methods and the association between blood pressure and mortality during intensive care unit (ICU) stay. Results A total of 96,673 paired blood pressure measurements from 6,060 unique patients were analyzed in the study. In Bland-Altman analysis, the bias (± SD, 95% limits of agreement) was 6.21mmHg (± 12.05mmHg, -17.41 to 29.83mmHg) for MAP, 0.39mmHg (± 19.25mmHg, -37.34 to 38.12mmHg) for SBP, and 0.80mmHg (± 12.92mmHg, -24.52 to 26.12mmHg) for DBP between the two techniques. Similarly, large limits of agreement were shown in different groups of NE doses. NE doses significantly affected the agreement between IBP and NIBP. SBP between the two methods gave an inconsistent assessment of patients’ risk of ICU mortality. Conclusion IBP and NIBP were not interchangeable in septic patients. Clinicians should be aware that non-invasive MAP was clinically and significantly underestimated invasive MAP.