PURPOSE: To demonstrate right/left asymmetry of the radial and femoral arteries.
METHODS: Forty consecutive patients in the Medical ICU who required arterial catheterization were studied. All measurements were made by one experienced operator. An Acuson Cypress 7.5 Mhz ultrasound probe with 0.1 mm resolution was used (Siemens AG, Malvern, Pennsylvania). Measurements were taken in the transverse orientation of the arterial diameter in 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. Chi square was used for statistical analysis where appropriate.
RESULTS: There were 21 male and 19 female patients. The average age was 59.6±16.5 years with an average body mass index of 25.5±7.2 kg/m2. The average size of the right radial artery was 2.42±0.77 mm. The average size of the left radial artery was 2.44±0.81 mm. The right radial artery was larger than the left 16/36 times, equal 4/36 times and smaller 16/36 times(p=1.0). The average absolute difference was 0.52±0.40 mm(range 0-1.5mm). 15/36 had >0.5mm difference and 5/36 had >1 mm difference. The average size of the right femoral artery was 8.75±2.11 mm. The average size of the left femoral artery was 8.49±2.23 mm. The right femoral artery was larger than the left 26/39 times, equal 1/39 times and smaller 12/39 times(p=0.037). The average absolute difference was 1.09±1.05 mm(range 0-3.9mm). 15/39 had >1mm difference in size and 5/39 had >2 mm difference in size.
CONCLUSION: The femoral and radial arteries are often asymmetric. The right femoral artery is usually larger than the left.
CLINICAL IMPLICATIONS: Ultrasound may be useful prior to arterial catheterization to identify the larger vessel.
DISCLOSURE: Lewis Eisen, None.