EditorAlthough the femoral vein (FV) is often used for central venous access, it carries a potential risk of femoral artery (FA) puncture. This complication is usually benign, but massive retroperitoneal haemorrhage,1 femoral nerve palsy2 and arterio-venous fistula3 have been reported. To avoid this complication, patient position is extremely important but the advantages of external leg rotation have not been reported. We have measured the anatomical relationships of FA and FV with the leg in external rotation or extension.
After ethical committee approval and written informed consent, 19 healthy male volunteers (mean age, height and weight 35.4 yr, 172.3 cm and 68.5 kg, respectively) were placed supine in a Fowler position with about 15° elevation, allowing dilation of the FV. The positions are shown in Figure 1A and B. Right femoral vessels were examined using an SSA-260A ultrasonograph (Toshiba, Tokyo, Japan) and a PLF-703NT 7.5-MHz linear probe (Toshiba, Tokyo, Japan) at 3 sites: at 0, 2 and 4 cm below the inguinal ligament (IL). Ultrasonographic images of the cross-sections of femoral vessels were obtained under minimum pressure between the probe and skin. FAFV overlap, depth of FV from the surface, and FV transverse and antero-posterior diameters were determined and compared. Wilcoxon single-rank testing was used for statistical analysis, with P < 0.05 considered statistically significant.
|
Our study demonstrates the anatomy of the femoral vessels of the right groin to 4 cm below the IL. In both positions, FAFV overlap and FV depth were minimal up to 2 cm below the IL. Below that, the FV runs more laterally and deeper, overlapping with the FA, and at 4 cm the FV lies just posterior to the FA and is completely hidden by the FA on anterior-view ultrasonography. The distal part of the FV runs laterally to the FA. This anatomy, with the FV crossing below the FA distal to the groin, is well described. Hughes performed in vivo ultrasonography in humans and described similar results to ours.4 Thus, our results appear to confirm that the optimal needle insertion site for safe femoral venipuncture is up to 2 cm below the IL.5 Our results also demonstrated that FAFV overlap is decreased in external rotation, which also has the effects of decreasing FV depth and increasing transverse and antero-posterior FV diameters; not only facilitating cannulation of FV, but also decreasing the risk of accidental FA puncture. External rotation of the thigh decreases lateral pressure against the femoral vessels by lateral shift of the ilio-lumbar and quadriceps muscles, and decreases muscle tension in these muscles.
Since Duffy introduced femoral vein catheterization,5 clinicians recommended external rotation for safe and reliable femoral venipuncture, presumably based on clinical experience. Our ultrasonographic study, in a small way, appears to support this view.
Saga, Japan
References
1 Sharp KW, Spees EK, Selby LR, Zachary JB, Ernst CB. Diagnosis and management of retroperitoneal hematomas after femoral vein cannulation for hemodialysis. Surgery 1984; 95: 905[ISI][Medline]
2 Ho KM, Lim HH. Femoral nerve palsy: an unusual complication after femoral vein puncture in a patient with severe coagulopathy. Anesth Analg 1999; 89: 6723
3 Fuller TJ, Mahoney JJ, Juncos LI, Hawkins RF. Arteriovenous fistula after femoral vein catheterization. JAMA 1976; 236: 29434
4 Hughes P, Scott C, Bodenham A. Ultrasonography of the femoral vessels in the groin: implications for vascular access. Anaesthesia 2000; 55: 1198202[CrossRef][ISI][Medline]
5 Duffy BJ. The clinical use of polyethylene tubing for intravenous therapy. Ann Surg 1949; 130: 92936[ISI][Medline]