Subcutaneous ventricular catheter reservoir and ventriculoperitoneal drain-related infections in preterm infants and young children.

OBJECTIVE: In the period January 1990 to September 1997, 70 patients, aged under 6 years were treated for hydrocephalus with a subcutaneous ventricular catheter reservoir and/or a ventriculoperitoneal drain at the University Hospital of Maastricht. METHODS: By means of a retrospective chart analysis, the number of shunt infections and related risk factors were analyzed. RESULTS: Twenty-one patients (30%) developed one or more infections, with an infection rate of 15.2% per surgical event. For an implanted reservoir or drain, the infection rates were 15.9 and 16.4%, respectively. The study group consisted of 39 (55.7%) preterm infants (< 37 weeks) and 31 (44.3%) full-term infants (> or = 37 weeks), with infection rates of 33.3 and 25.8%, respectively. At the first surgical intervention 28 patients (40%) had a postmenstrual age less than 37 weeks, with an infection rate of 46.4%. At the time of surgery, 69.7% of the patients were aged less than 6 months, with an infection rate of 19.6%. The most frequent causative microorganism of the shunt infections was Staphylococcus epidermidis (42.1%). CONCLUSIONS: Prematurity is an important risk factor for ventricular catheter reservoir and ventriculoperitoneal drain-related infections, especially for patients with a postmenstrual age of less than 37 weeks at their initial shunt placement and extreme low birth weight infants have a high risk for infection. In our opinion the use of adequate antibiotic prophylaxis and optimal infection control measures are necessary to keep the rate of infection as low as possible.

Sizing fine particles with the phase Doppler interferometric technique.

A theoretical model based on the Lorenz-Mie theory was used to study the response characteristics of the Aerometrics phase Doppler particle analyzer (PDPA). The validity of the model was verified experimentally, and its suitability for calculating measurement uncertainties was established. The theoretical and experimental results suggest that size resolutions of the order of +/-0.3 microm are possible when the PDPA is used to measure small spherical particles (< 10 microm). We show that the optical configuration of the PDPA plays an important role in establishing the sizing uncertainty of the instrument.