Mean arterial pressure maintenance following spinal cord injury: Does meeting the target matter?

Abstract

Neurosurgical guidelines recommend maintaining mean arterial pressure (MAP) between 85 and 90 mm Hg following acute spinal cord injury (SCI). In our hospital, SCI patients receive orders for MAP targeting for 72 hours following admission, but it is unclear how often the patient's MAP meets the target and whether or not this affects outcome. We hypothesized that the proportion of MAP measurements ≥85 mm Hg would be associated with neurologic recovery. Spinal cord injury patients with blunt mechanism of injury admitted between 2014 and 2019 were identified from the registry of a level 1 trauma center. Proportion of MAP values ≥85 mm Hg was calculated for each patient. Neurologic improvement, as measured by positive change in American Spinal Injury Association (ASIA) impairment scale by ≥1 level from admission to discharge was evaluated with respect to proportion of elevated MAP values. A total of 136 SCI patients were evaluated. Average proportion of elevated MAP values was 75%. Admission ASIA grades were as follows: A, 30 (22.1%); B, 20 (14.7%); C, 28 (20.6%); and D, 58 (42.6%). One hundred six patients (77.9%) required vasopressors to elevate MAP (ASIA A, 86.7%; B, 95.0%; C, 92.9%; D, 60.3%). Forty patients (29.4%) were observed to have improvement in ASIA grade by discharge (admission ASIA A, 15%; B, 33%; C, 40%; D, 13%). The proportion of elevated MAP values was higher for patients with neurologic improvement (0.81 ± 0.15 vs. 0.72 ± 0.25, p = 0.014). Multivariate modeling demonstrated a significant association between proportion of elevated MAP values and neurologic improvement (p = 0.028). An interaction revealed this association to be moderated by vasopressor dose (p = 0.032). The proportion of MAP measurements ≥85 mm Hg was determined to be an independent predictor of neurologic improvement. Increased vigilance regarding MAP maintenance above 85 mm Hg is warranted to optimize neurologic recovery following SCI. Therapeutic/care management, level IV.