How Many Lumens Should Be Cultured? Evaluating the Yield of Culturing All Lumens in Febrile Neutropenic Children with Cancer

Background

Obtaining blood cultures from all lumens of a central venous catheter (CVC) is the standard practice in children with cancer presenting with febrile neutropenia (FN) to optimize the diagnosis of catheter-related bloodstream infections (CRBSI). This approach, however, requires higher blood volumes and multiple culture bottles, raising questions about its necessity, particularly during periods of blood culture bottle shortages, such as in 2024. There is a lack of studies assessing the likelihood of missed CRBSI diagnoses when not all CVC lumens are cultured in FN episodes.

Methods

This single-center, retrospective study was conducted at Riley Hospital for Children in Indianapolis, Indiana, evaluating FN episodes in pediatric hematology-oncology patients from January 1, 2016, to December 31, 2023. We aim to evaluate the proportion of CRBSI episodes that would be missed if cultures were not obtained from all lumens of multi-lumen catheters. The study included cases of microbiologically proven CRBSI, differentiating true infections from contamination using NHSN definitions. Only episodes where cultures from all lumens were obtained simultaneously were included in the study

The analysis focused on double-lumen, triple-lumen, and quadruple-lumen catheters. For each catheter type, we calculated the probability of missed CRBSI diagnoses if blood cultures from one or more lumens were eliminated. Statistical modeling estimated missed diagnosis rates based on the distribution of infections across lumens. Confidence intervals (CIs) were derived using 1,000 simulated samples, and significance was assessed with a p-value threshold of <0.05.

Results

A total of 377 proven CRBSI episodes were identified from 2,648 FN episodes in 223 patients. After excluding cases where blood cultures were drawn from single-lumen catheters, 229 CRBSI episodes from 163 patients with multi-lumen catheters were included. This included 133 double-lumen, 73 triple-lumen, and 23 quadruple-lumen catheter episodes.

Eliminating cultures from one lumen resulted in missed diagnoses for 21%, 17.3%, and 28% of CRBSI episodes in double-lumen, triple-lumen, and quadruple-lumen catheters, respectively. If two lumens were excluded, the missed diagnosis rate increased to 34.7% for triple-lumen and 47% for quadruple-lumen catheters (see table)

Conclusions

This is the first study to assess the diagnostic yield of blood cultures obtained from all lumens of multi-lumen catheters and the probability of missed CRBSI diagnoses in pediatric cancer patients. Our findings highlight that eliminating cultures from even one lumen is associated with a substantial risk of missed CRBSI diagnoses. Physicians should consider these risks carefully, especially when adopting practices during resource-constrained periods, to ensure accurate diagnosis and optimal patient care.