[Infections related to external ventricular drainage].

Infection is the main complication of external ventricular drainage (EVD). This retrospective study assessed the relationships between EVD duration, antibiotics and cerebrospinal fluid (CSF) infection. From January 1990 to December 1991, 53 neurosurgical patients, aged 7-76 years, a simplified acute physiological score (SAPS) of 1-20 and having a total of 64 EVD, were included in this study. CSF withdrawn from the drain was collected daily for bacteriological, biochemical and cytological analysis, until the EVD removal. CSF colonization was defined by a positive direct examination or a positive culture of CSF, in the absence of biochemical and cytological abnormalities. CSF drain infection was defined by a low glucose concentration or leucocytosis without blood contamination. However the results of bacteriological analysis were modified by the antibiotics. The group of non infected patients and the group of those with an infected or a colonized drain were comparable with regard to underlying neurosurgical diseases, age, SAPS, Glasgow coma scale and delay between hospital admission and day of drain insertion and antibiotic administration. The EVD duration was significantly longer in infected EVD and colonized EVD. Staphylococci were the most frequently recognized bacteria and coagulase-negative staphylococci predominated in CSF of colonized EVD. In five patients, antibiotics were unable to cure a meningitis. Their leucocyte count was increased. The glucose concentration was low, but the culture, remained negative. It is concluded that duration and rate of EVD influence more the incidence of infections than the systemic administration of antibiotics.