Article
Nurse-to-patient-ratio as risk factor for nosocomial primary bloodstream infection in ICUs
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Published: | September 8, 2005 |
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Outline
Text
Objectives
Nosocomial primary bloodstream infections (BSI) cause significant morbidity and mortality among hospitalized patients and have an enormous economic impact. In several studies understaffing was identified as a risk factor for outbreaks of BSI. However, little is known about the influence of nurse-to-patient-ratios on BSI in endemic situations on ICUs. We investigated the nurse-to-patient-ratio as a possible risk factor for BSI in an endemic situation.
Methods
A prospective cohort study was done to identify exposures associated with cases of BSI. During an 18-month period all patients who were in one of two ICUs (A=12 and B=24 beds) for more than 3 days were included. Data collected on admission and discharge: admission date, age, sex, SAPS II, infections on admission, discharge date. Additional data collected during hospital stay: days on ICU, intubation, urinary tract catheter, central venous catheter, dialysis, surgical procedure during the stay on the ICU, and SOFA. Daily bed occupancy and nurse staffing on the ICU were also recorded. Nurse-to-patient ratio was determined by dividing nurse staffing by the patient density. Risk factor analysis included univariable approach and Cox proportional hazards regression analysis.
Results
In total 801 patients were treated in the two ICUs. There was no difference between patients with BSI and patients without BSI concerning mean of age, distribution of sex, average stay on ICU of patients with no BSI and average duration between admission and diagnosis of BSI of case patients, and numbers of infections on admission in the two groups. Patients with BSI had a significant higher SAPS II on admission as patients who developed no BSI. 21 patients (2.6%) had a BSI. The nurse-to-patient ratio of ICU A was 0.86 and of ICU B 0.91. The overall nurse-to-patient ratio in patients without BSI was 0.90 and in patients with BSI was 0.87. The Hazard ratio of nurse-to-patient ratio in the Cox analysis was 0.61; p=0.04, that means patients with average higher nurse-to-patient ratio per day had less BSIs.
Conclusions
BSI is highly dependent on hygienic behaviour. The result of the study underlines that staffing is an important point in patient safety in hospitals. To our knowledge is this the first study which investigated the influence of staffing on endemic BSI in one hospital where the patient was the unit of analysis.