Abstract
Purpose:
This IRB-aproved retrospective chart review is designed to ascertain if the administration of intravenous mannitol affects orbital volume as determined by computed tomography (CT).
Methods:
A list of patient’s who were administered intravenous mannitol with CT scans of the head prior to and after mannitol was obtained. Gender, age, and time between CT scans and mannitol administration were recorded. Orbital volume was calculated by calculating the area of the orbit for the five most superior CT slices that clearly contain the globe, and multiplying the average of consecutive slice areas by the thickness of each slice. This measurement method has been validated in prior literature. Pre and post-mannitol volumes were compared for each eye in each patient, and the significance of the change was determined by t-test.
Results:
Preliminary results were obtained from 9 patients (18 eyes). Five patients were male, and average age at time of mannitol administration was 57.94 year old. Average time between initial CT and mannitol administration was 15.47 hours, and average time from mannitol to follow-up CT was 26.17 hours. Area calculations showed an average gain in orbital volume of 19.08mm3 (+1.4%, p=0.36).
Conclusions:
This limited data series shows no statistically significant effect of mannitol on orbital volume. Scientific literature shows that mannitol decreases intracranial soft tissue volume. These preliminary results appear to show that orbital volume is affected differently by mannitol than intracranial tissues. Further study is required to determine if mannitol affects orbital volume.