External ventricular drain related infections: Why definitions matter, and generalizable risk reducing practices remain questionable

Jamjoom and colleagues report results of a prospective study, aiming to establish a national rate of external ventricular drain (EVD)-related infections (ERI) in the UK and Ireland and determine key factors influencing the infection risk1. While ambitious and laudable in purpose, these aims do not test specific hypotheses with any control or specific power, but rather explore a number of potential associations within the studied cohort. Herein, they faced dilemmas of definitions, problems of generalisability and a quagmire of exploratory associations implying potentially false causations.

The lack of hypotheses led the authors to be overinclusive, assessing all EVDs without specific stratification for vascular, trauma or other causes. And they chose a vague definition of ERI, which they defended as pragmatic: evidence of positive cerebrospinal fluid (CSF) culture (and/or gram stain) or clinical suspicion of ERI by the managing team due to CSF pleocytosis, …