Identify prognostic markers for patients with unilateral or bilateral fixed, dilated pupils (FDP). 

A fixed, dilated pupil in the setting of neurologic insult typically signifies acute mass effect and herniation. With contemporary neurocritical care, patients with FDP have variable functional outcomes. However, the proportion of patients with good outcomes and patient characteristics associated with good outcomes have not been well described.

From an existing IRB-approved database of 258 neurocritically ill patients who underwent external-ventricular drain (EVD) placement from 2010-2016, all 57 patients who had FDP >4mm were included. Using electronic medical records, demographics data about pre-morbid functional status, admitting diagnoses, radiological characteristics, interventions, and outcomes (discharge Glasgow Coma Scale (GCS) and Glasgow Outcome Scale (GOS)) were collected. Logistic regression was performed to identify factors predictive of mortality and discharge GOS. 

Admission GCS, sulcal effacement on admission or post-FDP imaging, midline shift on post-FDP imaging, maximum pupil size, and bilateral FDP were significantly correlated with patient mortality (p<0.05). Admission GCS and modified fisher, midline shift on post-FDP imaging, and bilateral FDP were significantly correlated with discharge GOS (p<0.05). 

Multivariable logistic regression and ordinal logistic regression were performed to ascertain the effect of age, sex, admission GCS, hydrocephalus or midline shift on admission imaging, maximum pupil size, and bilateral FDP on likelihood of patient mortality and discharge GOS, respectively. The multivariable logistic regression model was significant, χ2(8)=28.8, p<.001, and explained 65.0% (Nagelkerke R²) of variance in mortality. Controlling for other variables, high admission GCS was independently predictive of survival to discharge but bilateral FDP and male sex were independently predictive of mortality (p<0.05). Admission GCS (p=0.01) and bilateral FDP (p<0.01) were independently predictive of discharge GOS, controlling for other variables.

Admission GCS and bilateral FDP were independently predictive of mortality and discharge GOS in neurocritically ill patients requiring EVD for CSF diversion.