Intra-Arterial Versus Noninvasive Blood Pressure Monitoring: A Systematic Review and Meta-Analysis.

Background: Invasive intra-arterial blood pressure (IABP) monitoring is common in critical care. However, IABP might be unnecessary if noninvasive blood pressure (NIBP) measurements are similar to IABP measurements.

Objectives: To investigate differences between IABP and NIBP measurements and their clinical relevance.

Methods: In a systematic review and meta-analysis, multiple databases were searched for eligible studies from inception to September 2023. Primary and secondary outcomes were differences between invasive and noninvasive measurements of systolic blood pressure (SBP) and mean arterial pressure (MAP), respectively. Tertiary outcomes were differences of 10 mm Hg or greater in SBP and MAP between IABP and NIBP measurements. Outcomes were expressed as standardized mean differences and 95% CIs. Study quality and heterogeneity were assessed. The study was registered with PROSPERO (CRD42022383924).

Results: The meta-analysis included 23 observational studies (6549 patients). Standardized mean differences between IABP and NIBP measurements were 0.238 (95% CI, 0.121-0.355; P < .001; I2 = 87%) for SBP and 0.062 (95% CI, -0.065 to 0.189; P = .34; I2 = 87%) for MAP. Bland-Altman plots demonstrated that SBP values were often lower with NIBP than with IABP measurements. The prevalence (95% CI) of differences of 10 mm Hg or greater was 0.500 (0.415-0.584) for SBP and 0.330 (0.227-0.452) for MAP.

Conclusions: Measurement via NIBP may underestimate SBP; differences of 10 mm Hg or greater are relatively frequent. The clinical relevance of these differences remains unclear.