Association of Premorbid Blood Pressure with Vasopressor Infusion Duration in Patients with Shock

Abstract

Rationale: Guidelines for vasopressor titration suggest a universal target-mean arterial pressure (MAP) >65 mm Hg. The implications for patients with premorbid low/high blood pressure are unknown.Objectives: To investigate the relationship between premorbid blood pressure and vasopressor duration for patients with shock.Methods: We performed a retrospective cohort study of adults admitted with shock to Calgary ICUs (June 2012-December 2018). The primary exposure was premorbid blood pressure: low (systolic <100); normal (systolic 100-139 and diastolic <90); and high (systolic ≥140 or diastolic ≥90). The primary outcome was vasopressor duration; secondary outcomes included ICU/hospital length of stay and ICU/hospital mortality. We examined associations of premorbid blood pressure with vasopressor duration and length of stay using multivariable competing risk models and mortality using multivariable mixed-effects logistic regression.Measurements and Main Results: Of 3,542 admissions with shock, 177 (5.0%) had premorbid low, 2,887 (81.5%) normal, and 478 (13.5%) high blood pressure. Premorbid low admissions had lower MAPs (vs. normal or high premorbid admissions) over the duration of vasopressor use (P = 0.003) and were maintained nearest premorbid MAPs while receiving vasopressors (P < 0.001). After adjustment, premorbid low admissions had longer vasopressor use (median, 1.35 d vs. 1.04 d for normal; hazard ratio for discontinuation vs. normal, 0.78 [0.73-0.85]; P < 0.001) and premorbid high admissions had shorter use (median, 0.84 d; hazard ratio, 1.22 [1.12-1.33]; P < 0.001). Premorbid low admissions had longer adjusted length of stay and higher adjusted mortality than premorbid normal admissions.Conclusions: Premorbid blood pressure was inversely associated with vasopressor duration.

Keywords: ICU; blood pressure; goals; shock.