Mild Sedation Exacerbates or Unmasks Focal Neurologic Dysfunction in Neurosurgical Patients with Supratentorial Brain Mass Lesions in a Drug-specific Manner

Abstract

BACKGROUND: Sedation is commonly used in neurosurgical patients but has been reported to produce transient focal neurologic dysfunction. The authors hypothesized that in patients with frontal-parietal-temporal brain tumors, focal neurologic deficits are unmasked or exacerbated by nonspecific sedation independent of the drug used. METHODS: This was a prospective, randomized, single-blind, self-controlled design with parallel arms. With institutional approval, patients were randomly assigned to one of the four groups: "propofol," "midazolam," "fentanyl," and "dexmedetomidine." The sedatives were titrated by ladder administration to mild sedation but fully cooperative, equivalent to Observer's Assessment of Alertness and Sedation score = 4. National Institutes of Health Stroke Scale (NIHSS) was used to evaluate the neurologic function before and after sedation. The study's primary outcome was the proportion of NIHSS-positive change in patients after sedation to Observer's Assessment of Alertness and Sedation = 4. RESULTS: One hundred twenty-four patients were included. Ninety had no neurologic deficits at baseline. The proportion of NIHSS-positive change was midazolam 72%, propofol 52%, fentanyl 27%, and dexmedetomidine 23% (P less than 0.001 among groups). No statistical difference existed between propofol and midazolam groups (P = 0.108) or between fentanyl and dexmedetomidine groups (P = 0.542). Midazolam and propofol produced more sedative-induced focal neurologic deficits compared with fentanyl and dexmedetomidine. The neurologic function deficits were mainly limb motor weakness and ataxia. Patients with high-grade gliomas were more susceptible to the induced neurologic dysfunction regardless of the sedative. CONCLUSIONS: Midazolam and propofol augmented or revealed neurologic dysfunction more frequently than fentanyl and dexmedetomidine at equivalent sedation levels. Patients with high-grade gliomas were more susceptible than those with low-grade gliomas.