# Central Venous Access: IJ, Subclavian, and Femoral Approaches

## Introduction

Central venous catheterization is a core procedural competency for emergency medicine physicians. Indications include hemodynamic monitoring, vasopressor administration, volume resuscitation, transvenous pacing, and inadequate peripheral access. Mastery of all three primary sites -- internal jugular (IJ), subclavian, and femoral -- allows the clinician to adapt to clinical constraints such as trauma, coagulopathy, or ongoing CPR.

## Indications and Contraindications

Central venous access is indicated for vasopressor infusion, central venous pressure monitoring, hemodialysis access, rapid volume resuscitation via an introducer sheath, transvenous pacemaker placement, total parenteral nutrition, and failure of peripheral IV access. Absolute contraindications include infection overlying the insertion site and known complete thrombosis of the target vein. Relative contraindications include coagulopathy (which favors compressible sites such as the IJ or femoral vein), distorted anatomy from prior surgery or radiation, and contralateral pneumothorax (which contraindicates the ipsilateral subclavian approach).

## Anatomy Review

### Internal Jugular Vein

The IJ vein runs within the carotid sheath, lateral and slightly anterior to the carotid artery, deep to the sternocleidomastoid (SCM) muscle. The classic surface landmark is the apex of the triangle formed by the two heads of the SCM. Ultrasound guidance has made the IJ the preferred site in most emergency departments, with first-pass success rates exceeding 90 percent.

### Subclavian Vein

The subclavian vein courses over the first rib, beneath the clavicle, anterior to the subclavian artery. The landmark technique targets the junction of the medial and middle thirds of the clavicle, aiming toward the sternal notch. Studies examining prolonged dwell-time have shown that the subclavian site carries lower infection rates compared to IJ and femoral sites.

### Femoral Vein

The femoral vein lies medial to the femoral artery at the inguinal ligament. The anatomic relationship is remembered by the mnemonic NAVEL (Nerve, Artery, Vein, Empty space, Lymphatics, from lateral to medial). It is the most compressible site, making it preferred in coagulopathic patients, and it is accessible during CPR without interrupting chest compressions.

| Site | Advantages | Disadvantages | Preferred Scenario | Catheter Depth |
|------|-----------|---------------|-------------------|----------------|
| Internal Jugular | Ultrasound-guided (>90% first-pass); compressible | Carotid puncture risk; difficult during CPR | Default site with US available | R: 15–17 cm; L: 17–19 cm |
| Subclavian | Lowest infection rate; patient comfort | Pneumothorax (1–3%); non-compressible | Prolonged dwell time; awake patients | 15–17 cm |
| Femoral | Compressible; no pneumothorax; CPR-accessible | Highest infection/thrombosis with dwell time | Coagulopathy; cardiac arrest; emergent | 20–25 cm |

<image>Anatomy diagram showing cross-sectional view of the neck at the level of the thyroid cartilage, depicting the internal jugular vein lateral to the carotid artery within the carotid sheath, with the sternocleidomastoid muscle overlying both structures</image>

## Ultrasound-Guided Technique

Before the procedure, an ultrasound survey should confirm vessel patency, identify anatomic variants, and rule out thrombus. A high-frequency linear transducer (5 to 10 MHz) is used with a sterile probe cover. The vein is distinguished from the artery by its compressibility, lack of pulsatility, and distension with Valsalva maneuver. The short-axis (out-of-plane) approach places the transducer perpendicular to the vessel, and the needle tip is seen as a hyperechoic dot. The long-axis (in-plane) approach places the transducer parallel to the vessel, allowing the entire needle shaft to be visualized in real time. Intraluminal guidewire placement should be confirmed with ultrasound before proceeding to dilation.

## Seldinger Technique Step-by-Step

The patient is positioned in Trendelenburg for IJ and subclavian access, which reduces the risk of air embolism and distends the target vein. For femoral access, the patient is supine with the leg slightly abducted. Full barrier precautions are applied per the central venous catheter insertion bundle: cap, mask, sterile gown, sterile gloves, and a large sterile drape. The insertion site is infiltrated with 1 percent lidocaine. The introducer needle is advanced under ultrasound guidance until venous blood is freely aspirated. The J-tip guidewire is threaded through the needle, and the operator must never lose control of the wire. The skin is nicked with a scalpel at the wire entry site, and the dilator is advanced over the wire and then removed. The catheter is threaded over the wire to the appropriate depth (15 to 17 cm for a right IJ, 17 to 19 cm for a left IJ, 15 to 17 cm for subclavian, and 20 to 25 cm for femoral). The guidewire is removed, blood return is confirmed from all ports, each port is flushed with saline, and the catheter is secured.

<image>Step-by-step illustration of the Seldinger technique for central venous catheterization, showing needle insertion, guidewire threading, skin nick, dilation, and final catheter placement over the wire</image>

## Complications

Pneumothorax is most common with the subclavian approach, occurring in 1 to 3 percent of cases, and a post-procedure chest X-ray should be obtained. Arterial puncture is most common with the IJ approach and is managed with direct pressure for 10 to 15 minutes. Air embolism occurs when the catheter hub is open to the atmosphere while the patient is upright and is managed by placing the patient in the left lateral decubitus and Trendelenburg position. Guidewire embolism is prevented by never releasing the proximal end of the wire. Catheter-related bloodstream infection (CRBSI) is reduced by strict adherence to the central line bundle (hand hygiene, full barrier precautions, chlorhexidine skin preparation, optimal site selection, and daily review of line necessity). Thrombosis is most common at the femoral site with prolonged dwell time.

## Post-Procedure Confirmation

A chest X-ray is mandatory after IJ and subclavian placement to confirm tip position and rule out pneumothorax. The ideal catheter tip position is at the cavoatrial junction, where the superior vena cava meets the right atrium. Point-of-care ultrasound can rapidly assess for pneumothorax by checking for absent lung sliding and can confirm cardiac tip placement using the rapid atrial swirl test.

<image>Chest X-ray showing a properly positioned right internal jugular central venous catheter with the tip at the cavoatrial junction, with annotations identifying the SVC and right atrium border</image>

## Clinical Pearls

Ultrasound guidance is the standard of care for IJ access and should be used whenever available for all sites. The central line insertion bundle has reduced catheter-related bloodstream infection rates by up to 66 percent in large multicenter trials. In cardiac arrest, the femoral site allows access without interrupting compressions and does not require post-procedure imaging. Guidewire position should always be confirmed with ultrasound before dilating to prevent arterial dilation. If resistance is met during wire advancement, the operator should stop and reassess rather than forcing the wire.

## References

1. Brass P, Hellmich M, Kolodziej L, et al. Ultrasound guidance versus anatomical landmarks for internal jugular vein catheterization. *Cochrane Database Syst Rev*. 2015;1:CD006962.
2. Parienti JJ, Mongardon N, Megarbane B, et al. Intravascular complications of central venous catheterization by insertion site. *N Engl J Med*. 2015;373(13):1220-1229.
3. Pronovost P, Needham D, Berenholtz S, et al. An intervention to decrease catheter-related bloodstream infections in the ICU. *N Engl J Med*. 2006;355(26):2725-2732.
4. American College of Emergency Physicians. Emergency ultrasound guidelines. *Ann Emerg Med*. 2017;69(5):e27-e54.