OBJECTIVE External ventricular drains (EVDs) have an important role in the management of neurological disease, and their placement is a frequently performed neurosurgical procedure. Hemorrhage is a common complication of EVD placement and occurs more frequently than originally believed. There is also risk of hemorrhage with removal of an EVD, which has not been well described. The authors investigated the risk factors associated with placement and removal of EVDs at their institution. METHODS A database was created including patients who required EVD placement from March 2008 to June 2014 at the University of Minnesota. A retrospective chart review was completed, and data were collected for each patient. All cranial imaging studies during the index hospitalization were reviewed to identify hemorrhages associated with either EVD placement or removal. The study was performed using a research protocol approved by the University of Minnesota's institutional review board. RESULTS Four hundred eighty-two EVDs were placed during the designated time period. Among the cases in which patients underwent imaging after the placement procedure, hemorrhage was found in 94 (21.6%). The hemorrhage volume ranged from 0.003 cm3 to 45.9 cm3 (mean [± SD] 1.96 ± 6.48 cm3). Two of these hemorrhages resulted in additional interventions: 1 surgical evacuation and 1 contralateral EVD. In 55 (22.5%) of the 244 cases in which imaging was performed after EVD removal, hemorrhage associated with removal was identified. The mean volume of these hemorrhages was 8.25 ± 20.34 cm3 (range 0.012-82.08 cm3). Two EVDs were replaced, and 1 patient died as a result of a large hemorrhage. Large hemorrhages (> 30 cm3) occurred in 2 patients on placement (0.46%) and in 5 patients on removal (2.0%). In this series, decreased platelet levels on admission and an increasing number of EVD placement attempts correlated with an increased risk of hemorrhage on placement. Only those with an EVD placed at bedside were more likely to have hemorrhage on EVD removal. CONCLUSIONS Multiple studies have reported varying EVD hemorrhage rates while very few studies have described hemorrhage secondary to EVD removal. This is the first reported analysis of risk factors associated with hemorrhage on EVD removal. Hemorrhages occur relatively frequently following EVD placement and removal, though clinical significance of these events seems to be low.
Keywords: EVD = external ventricular drain; INR = international normalized ratio; OR = odds ratio; complication; external ventricular drain; hemorrhage; hydrocephalus; removal.