NOSOCOMIAL INFECTIONS IN AN ONCOLOGY INTENSIVE-CARE UNIT

Introduction: Treatment of cancer has contributed to a growing number of immunocompromised patients with life-threatening nosocomial infecti ons (NI). High mortality with considerable cost is observed when they are admitted to the intensive care unit (ICU). Few studies on infectio n control and surveillance have been undertaken in this population gro up. Methods: All patients treated at a six-bed medical-surgical oncolo gy ICU for >48 hours were prospectively observed for the development o f an NI and the influence of device utilization on infection rates. Th e analysis used the standard definitions of the National Nosocomial In fection Surveillance System Intensive Care Unit surveillance component . Results: From September 1993 through November 1995, 370 infections o ccurred in 623 patients during 4034 patient-days, for an overall rate of 50.0 per 100 patients or 91.7 per 1000 patient-days. Pneumonia (28. 9%), urinary tract infections (25.6%), and bloodstream infections (24. 1%) were the main types of infection. The most common microorganisms i solated were Enterobacteriaceae (29.7%), fungi (22.2%), and Pseudomona s aeruginosa (13.2%). The median device utilization ratios were 0.63, 0.83, and 0.86 for ventilator, indwelling urinary catheter, and centra l venous catheter, respectively. The highest median device-specific as sociated infection rate was 41.7 for ventilator. The median for the av erage length of stay was 8.8 days, and the average severity of illness score was 4.0. There was a strong positive correlation between the ov erall NI patient rate and device utilization (r = 0.56, p < 0.01), ave rage severity of illness score (r = 0.54, p < 0.01), and average lengt h elf stay (r = 0.67, p < 0.01). No correlations were statistically si gnificant when patient-days were used in the denominator. Among the de vices only the number of central venous catheter days was significantl y correlated with infections (r = 0.51, p = 0.01). The NI patient-day rates were progressively higher the longer the patients stayed in the ICU. Conclusions: The high rates reported in this study may reflect a combination of several factors related to the underlying illness, neut rophil count, and exposure to invasive procedures. The adjusted infect ion rates described here provide specific surveillance data for furthe r interhospital comparisons and also to assess the influence of invasi ve medical interventions, allowing the implementation of preventable m easures to control infections.