External ventricular drain infections at the Canberra Hospital: A retrospective study

External ventricular drains (EVD) are crucial for the emergency management of hydrocephalus and raised intracranial pressure. Infection is the most morbid and costly cause of EVD malfunction and can cost up to $50,000 US to treat per case. In 2007, Canberra Hospital changed EVD management protocols requiring set-up of EVD transducer systems in theatre, cessation of prophylactic antibiotics after 24hours, cerebrospinal fluid (CSF) samples second or third daily and discontinuation of elective EVD changes. The current study aimed to retrospectively audit EVD inserted between 2006 and 2010 in order to determine the impact of these changes. There was a non-significant downward trend in infection rates from 20.93% to 11.50% (p=0.343) after the protocol changes. Patient age (OR=1.032, p=0.064, confidence interval (CI): 0.998-1.067) and sex (OR=1.405, p=0.595, CI: 0.401-4.917) were not significantly associated with infection. However, multiple drains were associated with a significant increase in infections rates (OR=21.96, p=0.001, CI: 6.103-79.023) and systemic perioperative antibiotic prophylaxis was associated with decreased rates of infections (OR=0.269, p=0.044, CI: 0.075-0.964). Our study showed a non-significant downwards trend in infections with introduction of changes to hospital protocol and illustrated some risk factors for infection in the Australian setting.