Nosocomial Infections in Neurosurgical Intensive Care Units in the United States

BACKGROUND: Nosocomial infections (NIs) in intensive care unit (ICU) patients result in increased mortality, morbidity, and cost. However, little is known about the epidemiology of NIs in neurosurgical ICU (NSU) patients. METHODS: Data on NIs in NSU patients in hospitals participating in the National Nosocomial Infections Surveillance (NNIS) system from 1995 to 2001 were analyzed. A NSU is a patient-care area with neurosurgery as primary reason for admission or care by a neurosurgeon after head or spinal trauma. The pooled mean NI rate was calculated per patient and patient days spent in the NSU. Device utilization is the days each device was used (device days) divided by patient days. Device-associated infection rates were calculated for pneumonia, urinary tract infection (UTI), and bloodstream infection (BSI) and compared to those of surgical ICUs. RESULTS: Among 93,327 patients monitored for 334,217 patient days, 5,484 (5.9%) developed 7231 NIs. The most common NIs were pneumonia (30.8%) and UTI (30.4%). BSI (11.9%), lower respiratory infections (6.6%), surgical site infections (4.4%), and central nervous system infections (4.3%) also occurred. Meningitis or ventriculitis occurred in 43.8% of surgical site infections. Staphylococcus aureus was the most common pathogen in pneumonia and lower respiratory tract infections, whereas Escherichia coli was most common for UTI and coagulase-negative staphylococci was for BSI. Of 2225 pneumonias, 83.6% were ventilator-associated. Of 2,198 UTIs, 95.7% were catheter-associated. Of 860 BSI, 81.1% were central line–associated. In comparison with use in surgical ICUs, device utilization per patient day was lower for all three devices: central lines (0.46 for NSU, 0.65 for surgical), urinary catheters (0.80 for NSU, 0.84 for surgical), and ventilators (0.37 for NSU, 0.46 for surgical). Pooled mean device-associated infection rates per 1,000 device days were 4.6 for BSI (5.2 for surgical), 7.3 for UTI (5.1 for surgical), and 13.6 for pneumonias (9.9 for surgical). CONCLUSIONS: Nosocomial infections are relatively common in neurosurgical patients. Most of these infections were device-associated UTI and pneumonia.