Establishing a Long-Term Model for Analysis and Improvement of Underfilled Blood Culture Volumes

Changing culture: An intervention to improve blood culture quality in the emergency department

OBJECTIVE

Blood cultures (BCs) remain a key investigation in ED patients at risk of bacteraemia. The aim of this study was to assess the effect of a multi-modal, nursing-led intervention to improve the quality of BCs in the ED, in terms of single culture, underfilling and contamination rates.

METHOD

The present study was conducted in the ED of a large urban tertiary referral hospital. The study included four phases: pre-intervention, intervention, post-intervention and sustainability periods. A multi-modal intervention to improve BC quality consisting small group education, posters, brief educational videos, social media presence, quality feedback, small group/individual mentoring and availability of BC collection kits was designed and delivered by two senior ED nurses over 7 weeks. Study data comprised rates of single, underfilled and contaminated cultures in each of three 18-week periods: pre-intervention (baseline), post-intervention and sustainability.

RESULTS

Over the study period 4908 BC sets were collected during 2347 episodes of care in the ED. Single culture sets reduced from 56.2% in the pre-intervention period to 22.8% post-intervention (P < 0.01) and 18.8% in the sustainability period (P < 0.01). Underfilled bottle rates were also significantly reduced (aerobic 52.8% pre-intervention to 19.2% post-intervention, 18.8% sustainability, anaerobic 46.8% pre-intervention to 23.3% post-intervention, 23.8% sustainability). Skin contaminants were grown from 3.7% of BC sets in the pre-intervention period, improving to 1.5% in the post-intervention period (P < 0.001) and 2.1% in the sustainability period (P = 0.03). Total volume of blood cultured was significantly associated with diagnosis of bacteraemia.

CONCLUSION

Significant improvements in BC quality are possible with nursing-based interventions in the ED.

Modern Blood Culture: Management Decisions and Method Options

The optimal care of septic patients depends on the successful recovery of clinically relevant microorganisms from blood cultures and the timely reporting of organism identification and antimicrobial susceptibility testing (AST) results. Many preanalytic factors play a critical role in culturing microorganisms, and advancements in blood culture instrument technology have reduced the time to positive results. Additionally, rapid organism identification and AST results directly from positive blood culture broth via new methods help to further shorten the time from empiric to targeted treatment. This article summarizes the current state of blood culture methods, including preanalytic, analytical, and postanalytic factors that are available to clinical microbiology laboratories.