Femoral Central Venous Access

The use of invasive monitoring technologies and aggressive hemodynamic resuscitation protocols has increased. Therefore, the ability to gain rapid and accurate vascular access has become a skill that it is imperative for critical and emergency care physicians to possess.[1]

Peripheral veins can be used to gain access to the central venous system.[2] However, this requires the placement of long catheters via superficial veins that may be difficult to locate in emergency situations. The predictable anatomic locations of the internal jugular, subclavian, and femoral veins make them easy to cannulate in patients who are critically ill.

All routes of central venous access are associated with complications and possible failure. The less than ideal conditions under which such access is established also contribute to the incidence of complications. Compared with femoral site access, internal jugular or subclavian access was associated with a lower risk of catheter-related bloodstream infections (CRBSIs) in earlier studies; however, subsequent studies (2008-2010) indicated that there were no differences among these three sites with regard to the rate of CRBSIs.[3]

One of the most common methods for gaining central venous access in emergency situations is via femoral vein cannulation. The technique of accurately placing a femoral vein catheter depends on appropriate patient selection and a sound knowledge of anatomy. As with most other central venous cannulations, the modified Seldinger technique is used.

For more information on subclavian vein cannulation, see Central Venous Access, Subclavian Vein, Subclavian Approach and Central Venous Access, Subclavian Vein, Supraclavicular Approach.

The following are generally accepted indications for femoral venous catheter placement:

• Emergency venous access during  cardiopulmonary resuscitation (CPR), in that it provides a rapid and reliable route for the administration of drugs to the central circulation of the patient in cardiac arrest
• In hypotensive trauma patients, emergency access via the femoral route is recommended by some traumatologists immediately after two peripheral venous catheters are established; if peripheral access cannot be established expeditiously, femoral venous access is established immediately; femoral venous catheter placement is preferred to supraclavicular central venous access in patients with suspected superior vena caval injuries
• Urgent or emergency hemodialysis access
• Hemoperfusion access in patients with severe drug overdose
• Central venous pressure monitoring

In 2012, a task force of the American Society of Anesthesiologists published a set of practice guidelines for central venous access[4] ; this document was subsequently updated in 2020.[5]  In 2016, the Association of Anaesthetists of Great Britain and Ireland published a consensus document containing recommendations for safe vascular access.[6]

Absolute contraindications for femoral central venous access include the following:

• Venous injury (known or suspected) at the level of the femoral veins or proximally (ie, iliac veins or inferior vena cava)
• Known or suspected thrombosis of the femoral or iliac veins on the proposed side of venous cannulation
• Ambulatory patient (because ambulation increases the risk of catheter fracture and migration)

Relative contraindications for femoral central venous access include the following:

• Presence of bleeding disorders (innate or iatrogenic from the use of anticoagulants or thrombolytics)
• Distortion of anatomy due to local injury or deformity
• Previous long-term venous catheterization (which increases the risk of venous thrombosis)
• Absence of a clearly palpable femoral artery
• History of  vasculitis
• Previous injection of sclerosis agents
• Previous  radiation therapy

Anatomy

The femoral vein lies within the femoral triangle in the inguinal-femoral area (see the image below). The superior border of the triangle is formed by the inguinal ligament, the medial border by the adductor longus, and the lateral border by the sartorius. The apex of the triangle is formed by the sartorius crossing the adductor longus. The roof of the triangle is composed of the skin, subcutaneous tissue, the cribriform fascia, and the fascia lata. The concave floor is formed by the underlying adductor longus, adductor brevis, pectineus, and iliopsoas.

Femoral triangle anatomy.

The neurovascular bundle consists of the femoral vein, artery, and nerve, which lie within the triangle in that order from medial to lateral. The femoral sheath encloses the femoral artery and vein, and the nerve lies outside the sheath. The femoral canal is a space within the femoral sheath and medial to the femoral vein.

The femoral artery lies at the midinguinal point, which is midway between the pubic symphysis and the anterior superior iliac spine. The surface anatomy of the femoral vein is identified for venipuncture by palpating the point of maximal pulsation of the femoral artery immediately below the level of the inguinal ligament and marking a point approximately 0.5 cm medial to this pulsation.

Distally in the leg, the femoral vein lies almost posterior to the artery. This is important because arterial puncture is more likely in the sites distal to the inguinal ligament.[7]

Many clinical situations necessitate placement of central venous catheters. The choice of site is dictated by the specific advantages and disadvantages of each access method in the clinical situation being considered.

The femoral site is advantageous in patients who are critically ill because the femoral area is relatively free of other monitoring and airway access devices. If a bedridden patient requires central venous access, the femoral site allows relatively free movement of arms and neck without impeding the access line. In patients with severe coagulopathy or profound respiratory failure, femoral access precludes the risks of a development of a hemothorax or pneumothorax, both of which are potential complications of supraclavicular venous access.

The disadvantage of the femoral site is that it presents a field that is potentially contaminated because of its proximity to the perineal area. However, this disadvantage is disputed by many investigators, who point out that the incidence of CRBSIs at the femoral access site is not significantly different from the incidence at the supraclavicular access site.[8, 9]  The head and neck area is also potentially contaminated by excessive secretions in the critically ill patient who is intubated or has undergone a tracheostomy for airway access.[10]

For more information about the relevant anatomy, see Femoral Sheath and Inguinal Canal Anatomy and Arterial Supply Anatomy.

The basic materials required for central venous cannulation are widely available as prepackaged kits (see the image below). The components that are required to place a femoral vein catheter include the following[1] :

• Povidone-iodine or chlorhexidine solutions to swab and prepare the venipuncture site
• Sterile drapes and towels
• Sterile gloves
• Gown, mask, and cap
• Local anesthetic (lidocaine 1%)
• Needle, 26 gauge, with 2- to 5-mL syringe, for injecting local anesthetic
• Needle, 26 gauge, to be used as a finder needle
• Needle, 20-22 gauge, with 10-mL syringe, to access the femoral vein
• Flexible guide wire with J-tip
• No. 11 scalpel
• Dilator device for the skin and soft tissue overlying the vein
• Single- or multiple-lumen catheter
• Silk or nylon sutures, 3-0 or 4-0
• Needle holder
• Suture scissors
• Dressings (antibiotic ointment, gauze pads, cloth or plastic tape)

Triple-lumen catheter kit.

Anesthesia

Identify anatomic landmarks. Clean and prepare the proposed venipuncture site with alcohol and a povidone-iodine or chlorhexidine swab. Using a 26-gauge needle, infiltrate the skin and subcutaneous tissue over the site with 2-5 mL of lidocaine 1%. Anesthesia may be omitted in an emergency situation where venous access is required in an obtunded patient for expeditious administration of medications and fluids. For more information, see Local Anesthetic Agents, Infiltrative Administration.

Positioning

For femoral vein catheterization, the patient should be placed in the supine position with the hip in the neutral position.

Seldinger technique

The Seldinger technique is the most commonly used method of gaining central venous access. It was initially described in 1953 by Seldinger as a vascular access method for percutaneous arteriography.[11]  Although the Seldinger technique requires multiple sequential steps, intravascular access can be rapidly and reliably gained once these steps are mastered.[12]

Place the patient in the supine position, with the inguinal area adequately exposed to allow identification of anatomic landmarks. Decontaminate the area by painting it widely with povidone-iodine or chlorhexidine solution. Chlorhexidine is preferred because of its prolonged residual antiseptic effect (up to 6 hours after initial application). Use sterile drapes to isolate the femoral area.

After donning the gown, mask, cap and sterile gloves, identify the surface landmarks by palpation (see the image below). Identify the inguinal ligament and the femoral arterial pulsations. Identify a point approximately 1 cm below the inguinal ligament and 0.5-1 cm medial to the femoral arterial pulsation. Mark this point as the site for percutaneous access to the femoral vein.

Femoral triangle anatomy.

Ultrasound guidance, involving either plain two-dimensional (2D) ultrasonography (US) or Doppler US, has been considered as an alternative to identification of anatomic landmarks for determining the insertion site.[13, 14] A 2015 Cochrane review of 13 studies (N = 2341; 2360 procedures) found that 2D US guidance had small advantages in safety and quality over an anatomic landmark technique in femoral vein cannulation for central access.[15]  The review authors reached no certain conclusions regarding Doppler US guidance versus an anatomic landmark technique.

A 2019 position statement from the Society of Hospital Medicine recommended that providers use real-time US guidance for femoral venous access, on the grounds that this reduces the risk of arterial punctures and total procedure time and increases overall procedure success rates.[16]

Once the site has been determined, infiltrate the skin and subcutaneous tissue overlying the venipuncture site with 2-5 mL of 1% lidocaine solution (see Patient Preparation).

Identify the vein and gain initial access. Many advocate the use of a small (26-gauge) exploratory or “finder” needle on a 5-mL syringe to accurately identify the vein and gain initial access. However, experienced operators often omit the finder needle, instead using a 20- to 22-gauge needle on a 10-mL syringe for the initial venipuncture.

Insert the finder needle so that enters the skin at an angle of approximately 45º in a cephalic direction. Maintain a small amount of negative suction by elevating the plunger of the syringe. As the vein is punctured, a flash of dark venous blood into the syringe indicates that the needle tip is within the femoral vein lumen.

Next, place the larger (20- to 22-gauge) needle immediately adjacent to the finder needle, and enter the femoral vein again. Thread the flexible J-tip guide wire through the lumen of the needle and into the vein lumen. Then, gently advance the guide wire until approximately one fourth to one third of its length (ie, 8-10 cm) is within the lumen of the vein.

If resistance is encountered in advancing the guide wire, rotate it gently and then advance. Continued resistance indicates misplacement of the wire. Under no circumstances should force be used to advance the wire.

Remove the needle by threading it backward over the wire. Next, take the No. 11 scalpel and make a nick medial to the wire at the skin to permit easier passage of the dilator device. Thread the dilator device over the wire, and use it to create a tract in the skin and the subcutaneous tissue so as to facilitate passage of the catheter.

Remove the dilator device, and thread the catheter over the wire until the wire emerges from the distal end of the catheter. Grasp the distal end of the wire, and thread the catheter forward to an intravenous position. Withdraw the wire simultaneously to maintain constant control of the distal end.

Once the catheter is in an intravenous position and the guide wire has been completely withdrawn, secure the catheter with 3-0 or 4-0 nylon to suture the flanges to the skin. Confirm the intraluminal placement of the catheter tip by aspirating venous blood from the ports and flushing these with sterile saline solution.

The FLUSH (Flush the Line and UltraSound the Heart) test may be a useful alternative for confirming correct intravenous placement. In this test, the heart is visualized via a subxiphoid ultrasonic view while the central catheter is flushed with agitated saline solution. Horowitz et al found the FLUSH test to be a simple and reliable technique that appeared capable of accurately confirming femoral venous line placement.[17]

Apply antibiotic ointment at the site of skin entry, followed by sterile dressings.

Catheter-over-needle technique

A less commonly used technique used for percutaneous venous access is the catheter-over-needle method. In this technique, the vein is accessed by using a solid needle over which a short single-lumen catheter is already in place. Once the vein is cannulated, the catheter is threaded over the needle into an intraluminal position, and the needle is withdrawn, leaving the catheter in place.

Pearls

A helpful mnemonic to remember the location of the femoral vein is VAN (Vein, Artery, Nerve) which indicates the order in which the three structures are encountered from medial to lateral.

Another helpful mnemonic is NAVEL (Nerve, Artery, Vein, Empty space, inguinal Ligament), which describes the anatomy of the femoral region from lateral to medial.

The chest compressions given during cardiopulmonary resuscitation can produce venous pulsations. In this case, attempts to locate the vein by aspirating medial to the perceived femoral arterial pulsations may fail. Direct venipuncture over the pulsations should be attempted, because these may be venous pulsations.

To prevent needle displacement after the femoral vein is punctured, the needle can be stabilized with a hemostat when the syringe is being removed.

In difficult cases, a handheld Doppler ultrasound device can be used to identify the location of femoral arterial pulsations. Venipuncture can then be attempted medial to these pulsations.

If Doppler US is unsuccessful, a duplex ultrasound device with visual display can be used. The device most commonly used is a 7.5-MHz real-time mechanical sector transducer with an attached needle guide. The transducer is covered with a sterile sheath, and the femoral vessels can be identified on the attached monitor. The femoral vein can then be punctured under direct visualization.[18]

Compared with femoral central venous line placement based on anatomic landmarks alone, US guidance does increase the rate of success on first attempt; however, it has not been found to have a significant effect on the rate of arterial puncture or other complications.[15]

The complications associated with femoral venous cannulations are generally less severe than those associated with access via jugular or subclavian veins.[19]  This is largely because the risk of traumatizing intrathoracic structures is avoided. The following complications are commonly associated with femoral venipuncture[20, 12, 1] :

• Arterial puncture - This is more common when the femoral arterial pulsations are not pronounced, as in low-flow states, during circulatory arrest, or when due to iliac or femoral arterial stenosis
• Pseudoaneurysm formation
• Hematoma formation - This can be a result of arterial puncture venous perforation and is generally self-limited, except in coagulopathic patients, where it could extend to the retroperitoneal area
• Bowel penetration - This is more likely in patients with femoral hernias; although the bowel injury is generally self-limiting, the potential vascular contamination with intestinal flora can lead to  sepsis
• Bladder puncture - This is more likely to occur with a distended bladder; like bowel injury with a needle, it is generally self-limited, but the potential for vascular contamination poses a serious risk
• Psoas abscess - This complication is a result of penetration and contamination of the underlying psoas fascia
• Septic arthritis - This is more common in infants and is a result of puncture and contamination of the hip capsule
• Femoral nerve injury with resulting paresthesias
• Infection
• Thrombosis of the femoral or iliac veins ^[21]