Guidelines for vasopressor titration suggest a universal target-mean arterial pressure (MAP) >65 mmHg. The implications for patients with pre-morbid low/high blood pressure are unknown.
To investigate the relationship between pre-morbid blood pressure and vasopressor duration for patients with shock.
We performed a retrospective cohort study of adults admitted with shock to Calgary intensive care units (June, 2012-December, 2018). The primary exposure was pre-morbid blood pressure: low (systolic<100); normal (systolic 100-139 and diastolic<90); 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 pre-morbid blood pressure with vasopressor duration and length of stay using multivariable competing risks models and mortality using multivariable mixed effects logistic regression.
Of 3,542 admissions with shock, 177 (5.0%) had pre-morbid low, 2,887 (81.5%) normal, and 478 (13.5%) high blood pressure. Pre-morbid low admissions had lower MAPs (vs normal or high pre-morbid admissions) over the duration of vasopressor use (p=0.003) and were maintained nearest pre-morbid MAPs while receiving vasopressors (p<0.001). After adjustment, pre-morbid low admissions had longer vasopressor use (median: 1.35 days versus 1.04 days for normal; hazard ratio for discontinuation vs normal: 0.78 (0.73,0.85), p<0.001) and pre-morbid high admissions had shorter use (median: 0.84 days; HR 1.22 (1.12,1.33), p<0.001 ). Pre-morbid low admissions had longer adjusted length of stay and higher adjusted mortality than pre-morbid normal admissions.
Pre-morbid blood pressure was inversely associated with vasopressor duration.

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