Gender disparity in failure rate for arterial catheter attempts

We examined risk factors associated with failure of arterial catheterization in the medical intensive care unit of a large urban teaching hospital. We analyzed 92 consecutive arterial catheterizations by internal medicine house staff and critical care fellows. Of the 92 attempts, 26.1% were done on femoral arteries, and 73.9% were done on radial arteries. Failure, which occurred in 28% of attempts, was more common in female patients (P < .001). The failure rate was 50.0% for attempts on femoral arteries and 20.6% on radial arteries. Systolic blood pressure was significantly lower in patients where the attempt failed (P = .024). In univariate analyses, hemoglobin values were lower (P = .028) and number of percutaneous punctures were higher (P = .019) in patients where catheterization failed. After multivariate analysis, only gender and systolic blood pressure remained statistically significant. The strongest predictor of failure was female gender. A possible explanation not explored here could be smaller arterial size in female patients.