Should I Target the Blood Pressure from the Arterial Line or the Cuff? A Practical Approach for Dealing with Widely Discordant Measurements.

Blood pressure (BP) monitoring is essential in managing critically ill patients in the intensive care unit (ICU), particularly for ensuring adequate end-organ perfusion in hypotensive states. Invasive arterial catheters and noninvasive oscillometric cuffs are often used together, but discrepancies between the two methods are common. These differences can arise from technical factors (e.g., transducer leveling, cuff size and placement, arterial waveform damping) as well as patient-related factors (e.g., vasoconstriction, arrhythmias, altered arterial compliance). This creates a clinical dilemma: which measurement best reflects the patient's true perfusion pressure, and how should management be guided? This review offers a practical approach for addressing discrepancies between invasive and noninvasive BP measurements in adult hypotensive ICU patients, including those with shock requiring vasopressor support. Based on contemporary data, we propose that a difference greater than 10 mmHg in mean arterial pressure (MAP) between the two methods can serve as a pragmatic threshold to trigger structured evaluation, rather than a universal definition of clinical significance. MAP is prioritized as the key variable for assessing perfusion pressure. When a discrepancy is detected, clinicians are encouraged to integrate both measurements with clinical signs of hypoperfusion and to perform a systematic assessment of technical and physiologic contributors before deciding which value should guide treatment. We present a stepwise clinical decision-making algorithm that helps practitioners (1) recognize when a discrepancy is large enough to matter, (2) evaluate perfusion using bedside and laboratory markers, (3) identify technical or anatomic reasons for discordant readings, and (4) determine when more central arterial monitoring may be appropriate. By structuring the evaluation of discordant BP measurements, this approach aims to reduce the risk of unrecognized hypotension or overtreatment, support more consistent hemodynamic decision-making, and ultimately improve the management of critically ill, hypotensive patients.