Noninvasive Blood Pressure Monitoring Comparable to Invasive Method in Critical Care

In a recent groundbreaking study conducted at a tertiary care facility, researchers sought to determine the accuracy of noninvasive blood pressure (NIBP) monitoring compared to the invasive method using arterial catheters in critically ill patients. The findings, based on simultaneous measurements in 1852 adults, reveal a significant level of agreement between the two methods, shedding light on potential advancements in critical care monitoring.

The study results were published in the Journal of Intensive Care Medicine.

In the intensive care unit (ICU), arterial catheters are commonly employed for the invasive monitoring of blood pressure (BP). Nevertheless, the existing data comparing the precision of noninvasive methods to arterial catheters in ICU blood pressure measurements are constrained by small sample sizes and varied methodologies. Hence researchers from Washington DC, USA conducted a single center, observational study To determine the agreement between invasive arterial blood pressure monitoring (IABP) and noninvasive blood pressure (NIBP) in critically ill patients.

Conducted at a tertiary care facility, this observational study focused on critically ill adults to measure blood pressure (NIBP). Clinical features were examined at the time of blood pressure (BP) measurement, encompassing patient demographics, laboratory data, severity of illness, specific interventions (such as mechanical ventilation and dialysis), and vasopressor dose. The objective was to pinpoint specific clinical scenarios in which measurement agreement is either more or less likely.

Findings:

• The study unveiled a median difference of 6 mm Hg in mean arterial pressure (MAP) between invasive arterial blood pressure (IABP) and NIBP readings.
• This level of agreement, within a narrow interquartile range of 1-12 (P < 0.01), signifies a promising development in critical care monitoring.
• Logistic regression analysis identified five independent predictors of measurement discrepancy, providing valuable insights into factors influencing the variance between the two methods.
• Notably, increasing doses of norepinephrine were associated with a higher likelihood of discrepancy (adjusted odds ratio [aOR] 1.10, 95% confidence interval [CI] 1.08-1.12, P = 0.03 for every change in 5 µg/min).
• Lower MAP values (aOR 0.98, CI 0.98-0.99, P < 0.01 for every change in 1 mm Hg), higher body mass index (BMI) (aOR 1.04, CI 1.01-1.09, P = 0.01 for an increase in 1), increased patient age (aOR 1.31, CI 1.30-1.37, P < 0.01 for every 10 years), and radial arterial line location (aOR 1.74, CI 1.16-2.47, P = 0.04) were also associated with measurement discrepancies.

The study's authors emphasized the broad agreement observed between IABP and NIBP in critically ill patients across various blood pressure ranges and severity of illness. While certain variables were identified as predictors of discrepancies, their predictive capacity was characterized as modest. This insight could potentially guide future studies to determine which specific patient groups might derive enhanced benefits from arterial catheterization.

In conclusion, this groundbreaking study not only underscores the substantial agreement between invasive and noninvasive blood pressure monitoring in critically ill patients but also highlights the potential for a more personalized and less invasive approach to critical care.

Further reading: Haber EN, Sonti R, Simkovich SM, et al. Accuracy of Noninvasive Blood Pressure Monitoring in Critically Ill Adults. J Intensive Care Med. Published online January 12, 2024. doi:10.1177/08850666231225173