K. Piehler1, S. Van Wey1, D. Vo1, J. Ferrell1, E. Miller1, R. Rodriguez1, S. Tarras1 1Indiana University School Of Medicine, Indianapolis, IN, USA
Introduction: Guidelines recommend a mean arterial pressure (MAP) of 85 – 90 mmHg for the first seven days post-spinal cord injury (SCI) to potentially improve neurologic recovery. Vasopressors are often utilized to achieve this, but limited data exists on which patients may develop adverse drug reactions (ADR) due to their usage. The aim was to identify risk factors in patients with SCI who received vasoactive medications for MAP augmentation and experienced an ADR.
Methods: This single-center, retrospective cohort study included SCI patients admitted from January 1, 2018, to December 31, 2022. Inclusion criteria were patients admitted to the intensive care unit (ICU) with SCI, age ≥ 18 years, a targeted MAP goal ≥ 85 mmHg,?and received vasopressor administration for > 24 hours. ADRs were defined as myocardial infarction (MI), ischemic stroke, limb ischemia, arrhythmia, tachycardia, and bradycardia. Other data included demographics, past medical history, level of SCI injury, American Spinal Injury Association (ASIA) Impairment scale, type and duration of vasopressor usage, and sedation usage. Univariable analysis was performed using Chi-Squared, Fisher’s Exact test, and Mann-Whitney U test. Multivariable analysis was performed with logistic regression. Significance was set at p ≤ 0.05.
Results: A total of 117 patients met the inclusion criteria. The median age was 52 (38, 66) with a median Injury Severity Score of 26 (17, 33). The cervical spine was the most common injury level at 69.2%. Most patients presented as an ASIA A (33.3%). No patients had an MI, ischemic stroke, or limb ischemia. Fifty-one patients (43.6%) experienced an ADR: bradycardia (26.5%), tachycardia (16.2%), and arrhythmia (10.3%). On univariable analysis for all ADR, norepinephrine (NE) use (p=0.012), days of NE (p=0.006), midodrine use (p=0.035), age (p=0.05), and ASIA D (p=0.035) were significant. On univariable analysis for arrhythmias, dexmedetomidine (p=0.047) and age (p=0.034) were significant. For tachycardia, propofol (p=0.017) was significant. For bradycardia, age (p=0.011), NE use (p=0.034), days of NE (p=0.006), and midodrine use (p=0.025) were significant. On multivariable analysis for all ADR events, age was predictive of adverse events (Odds Ratio [OR] 1.065, 95% CI 1.028-1.103, p=<0.001,) while midodrine use (OR 0.027, 95% CI 0.080-0.862, p=0.027) and history of hypertension (HTN) (OR 0.098, 95% CI 0.027-0.351, p=<0.001) decreased odds of an adverse event. For bradycardia events, only age was predictive (OR 1.059, 95% CI 1.021-1.099, p=0.002), and HTN decreased risk of bradycardia (OR 0.208, 95% CI 0.058-0.745, p=0.016).
Conclusion: Augmented MAP management demonstrated no thrombotic events. A past medical history of HTN appears to decrease the odds of ADR, especially bradycardia. NE increased the risk of bradycardia, but this risk was not significant when stratified by midodrine use.