Recently, the investigators completed a retrospective review of a prospectively collected database of patients undergoing bedside EVD placement with the primary outcome of interest being catheter occlusion. This sample included 101 patients over a 1 year period. Two Codman catheters were available for use (Clear Bactiseal 'large' catheter: outer diameter 3.4 mm, inner diameter 1.9 mm; and Orange Bactiseal 'small' catheter: outer diameter 3 mm, inner diameter 1.5 mm). The decision regarding which catheter to use was made at the time of the procedure based on resident preference and availability. Both temporary occlusion (requiring flushing but patency could be restored) and permanent catheter occlusion (requiring replacement) were common, occurring in 41% and 19% of patients, respectively. Over 25% of small catheters became occluded during the study period compared to 11% of large catheters. Small catheters were associated with a 3.4 times greater odds of occlusion than the larger diameter catheters on multivariable regression analysis. This study suggests that the preferential use of larger diameter catheters may reduce the risk of ventriculostomy occlusion and need for replacement, however the study was not randomized and catheter selection may have been biased.