OBJECTIVES: We aimed to determine the frequency and variables associated with low femoral central venous catheter (fCVC) tip position. We also examined the association between tip position and symptomatic venous thromboembolism (VTE). DESIGN: Retrospective cohort from two PICUs. SETTING: Quaternary academic children's hospitals, 2016-2021. PATIENTS: Children (age <
18 yr) in the PICU who underwent temporary fCVC placement. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Low fCVC tip position occurs when the tip is inferior to the fifth lumbar vertebra (L5) on a postprocedural abdominal radiograph. Of 936 patients: 56.3% were 1-12 years old, and 80.0% had normal weight-for-age z score. fCVC tip position was low in 67.3% of patients. In the multivariable model, older age, earlier years of placement, and higher weight-for-age were associated with low fCVC tip position. Symptomatic fCVC-associated VTE occurred in 8.8% of patients, with a rate of 16.5 per 1000 CVC days (interquartile range, 13.1-20.5 per 1000 CVC days). The percentage of VTE in low vs. recommended fCVC tip position and VTE (8.6% vs. 9.2%) were equivalent (two one-sided z-tests
p <
0.001). Furthermore, in the multivariable model, we failed to identify an association between low fCVC tip position, relative to the recommended tip position, and greater odds of VTE (OR, 1.58 [95% CI, 0.92-2.69). However, we cannot exclude the possibility of low fCVC tip position being associated with up to 2.6-fold greater odds of symptomatic VTE. CONCLUSIONS: In our two PICUs, 2016-2021, low fCVC tip position occurred in two-thirds of placements and was associated with older age and higher weight-for-age patients. fCVC-associated VTE occurred in one-in-11-catheter placements, with the raw percentage of fCVCs and subsequent VTE in low and recommended tip position being equivalent. However, the multivariable modeling indicates that future research into the relationship between tip position and VTE requires ongoing surveillance and work.