(232) Evaluation of Clinical Outcomes of Midodrine on IV Vasopressor Requirements in Critically Ill Adults

Introduction: Adjunctive midodrine is used off-label for IV vasopressor-sparing benefit (faster vasopressor discontinuation and increased vasopressor-free days), yet recent evidence suggests this lacks clinical significance. This study aimed to evaluate midodrine’s effect on cumulative IV vasopressor requirements.

Methods: A single-center, retrospective chart review was conducted in adult ICU patients who received midodrine while on ≥1 IV vasopressor from July 2022 to June 2023. Exclusion criteria were midodrine allergy or prior exposure, death within 24 hours, and receiving < 3 midodrine doses. The primary outcome, mean cumulative vasopressor doses, was reported in mcg/kg/min norepinephrine equivalents (NEE). Secondary outcomes included vasopressor-free days, daily mean arterial pressure (MAP), ICU readmission rates, and clinically important adverse effects. Descriptive statistics were used, including Chi-square and independent t-tests, with significance defined as p-value ≤0.05.

Results: Sixty patients were included (30 midodrine and 30 control). Groups were similar at baseline, with mean age 67.2±15.5 versus 64.8±11.2 years and MAP 79.8±17.9 versus 88.6±21.1 mmHg in midodrine and control, respectively. The most common IV vasopressors were norepinephrine (97% midodrine and 100% control) and vasopressin (67% midodrine and 83% control). Mean cumulative IV vasopressor duration was 12±12.3 versus 6±4.7 days (p=0.01) and mean cumulative IV vasopressor doses were 0.064±0.049 versus 0.046±0.098 NEE (p=0.31) in midodrine and control, respectively. Mean cumulative MAP was higher in midodrine patients (82±4.7 versus 78±6.6 mmHg, p=0.01). Total vasopressor-free days were 4.8±6.0 versus 4.4±4.7 in midodrine and control, respectively (p=0.84). ICU readmission was higher in midodrine patients (17% versus 7%), yet ICU all-cause mortality rate was higher in control patients (67% versus 27%). In both groups, 5 patients (17%) experienced clinically significant bradycardia, while more midodrine patients experienced supine hypertension (67% versus 57%).

Conclusions: Adjunctive midodrine was not associated with significant changes in mean cumulative IV vasopressor doses or vasopressor-free days, yet it resulted in significantly higher mean cumulative MAP. However, midodrine patients may have been more acutely ill at baseline.