280 Arterial Line versus Noninvasive Blood Pressure Monitoring in Hypertensive Emergencies

Abstract

Blood pressure (BP) monitoring is important for managing patients with hypertensive emergencies. Management of such conditions often involves relatively narrow and specific blood pressure windows. While invasive arterial blood pressure (IABP) monitoring is considered the gold standard method of BP measurement, its usefulness is unclear. Although previous studies demonstrated differences between IABP and NIBP values, few had assessed whether these differences would affect clinical management. Our study aimed to determine whether the difference between NIBP and IABP would change BP management in patients with hypertensive emergencies. This was a prospective observational study of adult patients with any hypertensive emergency admitted to the Critical Care Resuscitation Unit (CCRU) at a quaternary academic center from January 2019—April 2021. We included consecutive patients with diagnoses of ischemic stroke, acute aortic disease, spontaneous intracranial hemorrhage (sICH), etc, and who required arterial monitoring. We excluded patients who had hypertensive diagnoses but required vasopressors due to overtreatment of anti-hypertensive medications or those who had arterial catheters prior to arrival. All arterial catheters were inserted upon patients’ arrival per CCRU clinical policy. Patients who had IABP and NIBP in the same extremity and four consecutive measurements of each modality following arterial catheter placement were eligible. Before arterial catheter placement, we recorded in real time clinicians’ decisions to manage patients’ systolic BP (SBP) according to the NIBP values and current guidelines, for example maintaining SBP ≤160 mmHg for patients with sICH. After the arterial catheter was placed, we again recorded in real time clinicians’ management of patients’ arterial SBP. We defined change in clinical management as any difference in blood pressure management (eg, adding a new antihypertensive agent, increasing or decreasing dose). We used Classification and Regression Tree (CART) analysis to identify sensitive and specific clinical predictors of management differences. A total of 183 patients were identified and analyzed, 71 (39%) female. Mean age was 63 years (standard deviation [SD] 14), mean body mass index (BMI) was 29 (6). Mean difference between IABP and NIBP and was 11 mmHg (95% CI 5-17). One hundred and seventeen patients (64%) had difference >10 mmHg between the two modalities, while 70 (38%) had a difference >20 mmHg. Seventy-nine patients (43%) had a change in management after arterial catheters were inserted. The most important factors in predicting management change included mean SBP >148 mmHg. Subsequent important factors were BMI >21, difference in BP value [IABP – NIBP] >6 mmHg, and diagnoses of ruptured abdominal aortic aneurysm, ischemic stroke + alteplase, any aortic dissection. Arterial BP monitoring identified a change in clinical management in almost half of patients with hypertensive emergencies. Clinicians should consider using arterial BP monitoring more frequently in the management of hypertensive emergencies, especially when strict BP goals are warranted.View Large Image Figure ViewerDownload Hi-res image Download (PPT)