Recurrent sampling and ventriculostomy-associated infections: a case-control study.

BACKGROUND: External ventricular drain (EVD) insertion is a common neurosurgical procedure with a significant risk of ventriculostomy-associated infections (VAIs), other morbidities and mortality. Several risk factors have been identified but their effect is unclear.

OBJECTIVE: Our primary objective was to assess whether recurrent EVD sampling increased the risk of VAIs. The secondary objective was to explore the effect of sampling frequency, duration of EVD stay, presence of cerebrospinal fluid leak and concurrent infections.

METHODS: Ours was a retrospective, single-centre, age-matched, case control study of 83 patients and 249 controls who underwent EVD insertion between 1 January 2010 - 31 December 2016. Patients with primary CNS infections, age under 1 year and death within 5 days of EVD insertion were excluded. Blinded abstractors collected all patient data through the electronic patient record system and regression analysis was used to compare the two groups.

RESULTS: Sampling the EVD more than once did not increase the risk of infection (OR 0.47, 95% CI 0.27-0.83, p = 0.01). Risk factors significantly associated with VAI included CSF leak (OR 2.06, 95% CI 1.16-3.67, p = 0.01), concurrent infection (OR 1.85, 95% CI 1.09-3.16, p = 0.02), and an EVD duration of >10 days (OR 2.28, 95% CI 1.24-4.18, p = 0.01).

CONCLUSION: Our findings do not support the notion that increased sampling of EVDs is associated with a higher risk of VAI. CSF leaks, concurrent infection and long-term EVDs are also statistically significant risk factors for infection.