PURPOSE: In a previous study we showed that arterial catheterization was less likely to be successful in critically ill women than in men. The purpose of this study is to determine whether this is influenced by the relative sizes of radial and femoral arteries in men and women.
METHODS: The study took place in the medical intensive care unit of a large urban teaching hospital. Over a four-month period, 40 consecutive patients (21 male, 19 female) patients requiring arterial catheters had their gender, body mass index and age recorded. An experienced ultrasound operator measured the diameters of both radial and femoral arteries using an Acuson Cypress 7.5 MHz ultrasound probe with 0.1 mm resolution (Siemens AG, Malvern, Pennsylvania). Measurements were taken in the transverse orientation of the arterial diameter during systole. Radial arteries were measured 2 cm proximal to the distal wrist crease. Femoral arteries were measured 1/3 of the way from the pubic symphysis to the superior iliac crest. Associations between patient characteristics and arterial size were assessed by univariant and multivariate analyses.
RESULTS: The average age of the cohort was 59.6±16.5 years (males58.0 ±15.3, females 61.4±18.0, p=0.53) with an average body mass index of 25.5±7.2 kg/m2(males 25.4±7.0, females 26.5±8.1, p=0.66). Men had significantly larger arterial diameters than women for radial (3.0±0.5mm vs. 1.9±0.5mm, p<0.001) and femoral (9.8±1.5 vs. 7.2±1.7, P<0.001) arteries. After adjustment for age and body mass index, male gender was significantly associated with larger radial (OR 1.1, 95% CI 0.8-1.4,p<0.001) and femoral (OR 2.6, 95% CI 1.5-3.7, P<0.001) arteries.
CONCLUSION: Female patients have significantly smaller femoral and radial arteries than male patients even when controlled for age and body mass index.
CLINICAL IMPLICATIONS: Smaller arterial size in female patients may account for the reduced likelihood of successful catheterization.
DISCLOSURE: Taro Minami, None.