Physicians in training, learn and practice research “To formulate, ingrain, and measure, a method of thought, investigation, and evaluation necessary for physicians to have multi-lateral information exchange and communication with experts in areas of scientific and medical discovery, knowledge, and 

Introduction: The placement of an external ventricular drain (EVD) for monitoring and treatment of increased intracranial pressure is not without risk, particularly for the development of an associated ventriculitis. The goal of this study was to investigate the presence of any CSF, serum or clinical parameters that would help to predict ventriculitis before it occurs; thus allowing for the determination of optimal timing of CSF collection for patients with in-situ EVDs. Methods: An observational retrospective study was conducted on patients from the Neurosurgery census between January 2006 and May 2012. A total of 466 patients were identified as having an in-situ EVD placed. Inclusion criteria were age >18 years, GCS 4-15, and placement of EVD for any indication. Our exclusion criteria included any recent history of meningitis, cerebral abscess, cranial surgery or open skull fracture within the previous 30 days. A broad definition of ventriculitis was used to separate patients into two categories: Suspected Ventriculitis (meeting all 3 CSF criteria while having no organism on CSF culture); and Confirmed Ventriculitis (presence of any organism on CSF culture). CSF sampling was conducted every other day of the week (Monday, Wednesday, Friday). Results: A total of 466 patients were identified as having an EVD placed during the study and 123 patients were included in the final analysis after exclusion criteria were applied. The incidence of ventriculitis was found to be 8.8%. Only one of variables being studied, the ratio of glucose CSF:serum < 0.5 was found to be of statistical significance, though not predictive of developing a ventriculitis. Conclusions: The authors feel confident that this study demonstrates no reliable CSF, serum, or clinical parameters that can effectively predict the development of ventriculitis in an EVD patient. Thus, we recommend and will continue to draw CSF samples on patients with in-situ EVDs on our previously established schedule of Monday/Wednesday/Friday for as long as the EVD remains in place. Introduction The use of the external ventricular drain (EVD) serves a dual function in the neurosurgical patients. It not only serves as a diagnostic monitor to detect elevated intracranial pressure (ICP), but also serves a therapeutic role in its ability to drain cerebrospinal fluid (CSF) in the setting of elevated ICP. While the ICP device is used in many neurosurgical patients, including but not limited to, those with subarachnoid hemorrhage (SAH), intracranial hemorrhage (ICH), or acute hydrocephalus; it is not without complications. The most commonly noted complication is ventriculitis. Incidence rates vary depending on the institution, and range from 0-22%, but more commonly tend to lie within the 1017% range 1-6,8,10 . The rate of ventriculitis tends to be associated with a higher morbidity and mortality for the neurosurgical patient 5,6 . Recent improvements in sterility techniques, antibiotic-impregnated catheters, and appropriate antibiotic administration have helped to decrease the rate of ventriculitis 5,6, . In a prospective epidemiologic study, Mayhall et al 7 analyzed the risk factors for ventriculitis in 172 consecutive neurosurgical patients. Their proposal stated that infection rates may be lowered by prophylactic exchange of catheters at 5-day intervals. However, a decade later, Holloway et al 1 showed that replacement of catheters prior to 5-days did not show a lower infection rate as compared to catheters exchanged at intervals of 5-days or greater. Over time, several approaches have been suggested to prevent ventriculitis, such as use of prophylactic antibiotics at time of insertion, during the first 24 hours post-insertion, and in a prolonged systemic fashion while the EVD is in place 11 . However, there is no consistent practice regarding the use of prolonged systemic antibiotics with EVD and the preference is largely related to tradition and training 11, 12 . Early detection of ventriculitis is imperative for successful treatment and for minimizing the possibility of future infections 3 . However, the clinical detection of ventriculitis can be difficult. For example, a study by Muttaiyah et al 4 determined that there was no associated temperature spikes with ventriculitis. However, CSF glucose levels were notably lower in these patients. An important consideration in the control of ventriculitis is the surveillance of CSF and monitoring for clinical symptoms of ventriculitis 9 . Currently, the issues of when and how often CSF sampling should be performed remains controversial ,9 . Routine CSF sampling has been reported as daily 2,9,16,17 , every 3-5 days 6,18-20 , only at EVD insertion, or only as clinically indicated 1,21,22 . In a study by Williams et al 3 , investigators sought to examine how the incidence of ventriculitis was affected by CSF sampling frequency, by decreasing surveillance from daily to every three days. Their results demonstrated that the incidence of ventriculitis decreased from 17% to 10.8% after changing CSF surveillance to every three days 3 . Naturally, one would assume that a breach of the EVD drainage system for sampling the CSF would increase the risk of contamination and subsequent infection. However, this risk must be balanced by the morbidity and mortality of ventriculitis if it remains undetected. This is especially important in light of the established literature showing the difficulty of clinical detection of ventriculitis. Current standard practice at our institution is to sample CSF upon insertion of EVD, followed by sampling every Monday, Wednesday, and Friday for as long as the EVD remains in place. As a result of these challenges, we decided to examine whether changes in any CSF, serum, or clinical parameters can help predict ventriculitis before it occurs, and if the current collection schedule of CSF is necessary. Materials and Methods The patients included in this study were identified during the course of the study using their medical record numbers. We performed a retrospective observational study of the Neurosurgical Census, for patients with in situ EVD from January 2006 to May 2012. A total of 466 patients were identified. Medical records were then used to classify patients by age and gender, indication for EVD, the duration of EVD, CSF and serum laboratory data, daily temperatures, changes in GCS, CSF culture, and the presence of other infections. To be included in the study, patients had to be 18 years or older, have an EVD (regardless of indication), and GCS 4-15. Patients with any recent (defined as within the last 30 days) history of meningitis, cerebral abscess, craniotomy or open skull fracture were excluded from the study. Figure 1: The criteria for patient selection, as well as the number of patients that were included in the study. At our institution, EVDs are placed by standard neurosurgical sterile technique in either the operating room, the emergency department, or in the intensive care unit, and are then connected to a sterile closed circuit system. All ventriculostomy catheters were non-antibiotic impregnated Integra trauma catheters. After the EVD has been sutured into place, a BioPatch is placed where the catheter exits the skin and a Tegaderm is placed to cover the BioPatch and catheter. As per standard Neurosurgical protocol, a non-contrast Computerized Tomography (CT) scan was obtained after placement to rule out hemorrhage caused by placement and to confirm satisfactory placement of the catheter. In regards to patients with an EVD, per current institutional protocol for the Department of Neurosurgery, CSF samples are drawn every other day during the week (ie: Monday, Wednesday, Friday) for as long as the EVD remains in place. CSF samples are drawn solely by the neurosurgery residents or attending physicians. The stopcock just distal to the catheter insertion site is turned off from the drainage system and the proximal port is cleaned with chlorahexidine twice. A sterile syringe is connected to the port and 3-5 ml of CSF is slowly withdrawn and then discarded. The port is then cleaned a second time and another 3-5ml of CSF is withdrawn, and sent for culture and analysis using standard methods. For patients in our study, the aforementioned laboratory and clinical parameters were collected on the day of EVD placement (“day 0”). Additionally, the following data was collected on the day of EVD placement (“day 0”), as well the day prior (“day -1”) and two days prior (“day -2): serum WBC, temperature, GCS, and cultures from other bodily sources (including sputum, nasal, urine, blood, neck, or tracheostomy). The schema for the time-based collection of all laboratory and clinical data can be found in Table 1. Table 1: schema showing the timeline of data collection on the day of CSF draw (Day 0), and previous