Annex 4. Cannulating the femoral vein

In a shocked adult or child with hypotension and collapsed peripheral veins, the femoral veins may provide the only possibility for venous access.

Anatomy

The femoral vein lies immediately medial to the femoral artery at about the midpoint of the inguinal (Poupart’s) ligament at the groin (Fig. 16).

Method

With the patient lying supine with the right thigh slightly abducted and externally rotated, locate the femoral arterial pulse at the groin with the index and middle fingers of your left hand. Clean the skin thoroughly with alcohol or iodine and, with full sterile precautions, mount the cannula with its introducing needle on a syringe. Puncture the skin just medial to the femoral artery, just below the groin crease, and, with the cannula assembly at an angle of 45°, advance gently, aspirating repeatedly until the vein is entered and blood drawn back. If the needle meets firm resistance withdraw, millimetre by millimetre, aspirating each time until blood can be drawn back freely with the syringe. Once you are confident that the needle tip is in the lumen of the vein, flatten the angle slightly and advance the cannula into the vein. Secure the cannula in place with a gauze pad and sticking plaster. Alternatively, the left femoral vein may be cannulated; this is more convenient if the operator is lefthanded.

Caution

Infection and thrombosis of the femoral vein are serious complications. Avoid leaving a femoral cannula in place for longer than is absolutely necessary.

Fig. 16. Location of the femoral arterial pulse and site for insertion of a femoral venous cannula