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A Retrospective Evaluation of Critical Care Blood Culture Yield – Do Support Services Contribute to the “Weekend Effect”?

Morton, Ben ORCID:, Nagaraja, Shankara, Collins, Andrea ORCID:, Pennington, Shaun ORCID: and Blakey, John D (2015) 'A Retrospective Evaluation of Critical Care Blood Culture Yield – Do Support Services Contribute to the “Weekend Effect”?'. PLoS ONE, Vol 10, Issue 10, e0141361.

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The “weekend effect” describes an increase in adverse outcomes for patients admitted at the weekend. Critical care units have moved to higher intensity working patterns to address this with some improved outcomes. However, support services have persisted with traditional working patterns. Blood cultures are an essential diagnostic tool for patients with sepsis but yield is dependent on sampling technique and processing. We therefore used blood culture yield as a surrogate for the quality of support service provision.

We hypothesized that blood culture yields would be lower over the weekend as a consequence of reduced support services.

We performed a retrospective observational study examining 1575 blood culture samples in a university hospital critical care unit over a one-year period.

Patients with positive cultures had, on average, higher APACHE II scores (p = 0.015), longer durations of stay (p = 0.03), required more renal replacement therapy (p<0.001) and had higher mortality (p = 0.024). Blood culture yield decreased with repeated sampling with an increased proportion of contaminants. Blood cultures were 26.7% less likely to be positive if taken at the weekend (p = 0.0402). This effect size is the equivalent to the impact of sampling before and after antibiotic administration.

Our study demonstrates that blood culture yield is lower at the weekend. This is likely caused by delays or errors in incubation and processing, reflecting the reduced provision of support services at the weekend. Reorganization of services to address the “weekend effect” should acknowledge the interdependent nature of healthcare service delivery.

Item Type: Article
Subjects: W General Medicine. Health Professions > Health Services. Patients and Patient Advocacy > W 84 Health services. Delivery of health care
QY Clinical Pathology > Blood. Blood Chemistry > QY 408 Physical examination
WA Public Health > WA 20.5 Research (General)
WA Public Health > Health Administration and Organization > WA 546 Local Health Administration. Community Health Services
Faculty: Department: Clinical Sciences & International Health > Clinical Sciences Department
Digital Object Identifer (DOI):
Depositing User: Jessica Jones
Date Deposited: 26 Jan 2016 14:18
Last Modified: 13 Sep 2019 08:25


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