A radiographic analysis following the proximal irrigation of occluded external ventricular drains: a cautionary note.

Dear Editor, Ventriculostomy catheter occlusion is a common complication after external ventricular drain (EVD) placement, with series demonstrating non-patent EVD in 19-47 % of patients [1–4]. A common technique for restoring patency involves the irrigation (flushing) of sterile saline proximally into the catheter to mechanically disrupt debris obstructing the catheter holes or tubing. However, there are no published data to date on the risks associated with catheter irrigation. We therefore sought to perform a retrospective analysis to examine the radiographic sequelae of this frequently performed intervention. As part of an ongoing Institutional Review Boardapproved prospective database of bedside EVD placement at our institution, we monitored the incidence of temporary and permanent catheter occlusion, need for replacement, and frequency of catheter irrigation [3]. The database was initiated in August 2013 and had, at time of analysis, enrolled 99 patients. In this study, all temporary catheter malfunctions treated with catheter proximal flushing or manipulation, as documented by nursing staff or physicians, were defined as a catheter irrigation. A full description of methods may be found elsewhere [3]. All enrolled patients who underwent at least one catheter irrigation (41 of 99 patients) were candidates for inclusion in this irrigation analysis. Those patients with two brain computed tomography (CT) studies performed within 48 h of each other were then reviewed for the incidence of catheter irrigation between the two CT scans. Patients who underwent any confounding neurosurgical procedure (craniotomy, aneurysm coiling, EVD replacement, contralateral EVD placement, lumbar puncture, etc.), those with aneurysmal re-rupture, or those being therapeutically anticoagulated or heparinized were excluded. As such, the goal of the analysis was to identify patients with two CTstudies of the brain performed within 48 h where the only intervention performed between CT studies was the proximal irrigation of the EVD catheter. CT imaging was then compared for the development of intercurrent hemorrhage, cerebral edema, or pneumocephalus. In addition, all enrolled patients who did not undergo catheter irrigation (58 of 99 patients) were potential candidates for inclusion in a control group analysis if they had two brain CT studies performed within 48 h of each other, without a confounding neurosurgical procedure performed during the interim. Nine of the 41 patients requiring catheter irrigation met inclusion for the radiographic irrigation analysis by having two head CT studies performed within 48 h, during which time proximal catheter irrigation was performed at least once, without intercurrent neurosurgical procedure. Three of these patients (33 %) had evidence of new hemorrhage around the catheter, four (44 %) demonstrated pneumocephalus around the catheter tract and two (22 %) showed evidence of injury along the tract with new edema (Fig. 1). This is in stark comparison to patients in the control group, where none of the 17 repeat CT scans demonstrated increases in edema, hemorrhage or pneumocephalus. To our knowledge, this is the first known report of the radiographic sequelae of EVD catheter irrigation for the purposes of restoring patency. While it cannot be definitively * Kyle M. Fargen fargen@musc.edu