If a central line, which is intended for placement in a large vein, is accidentally inserted into an artery, it can lead to a range of serious and potentially life-threatening complications due to the higher pressure and different flow dynamics of the arterial system.
What Happens If a Central Line Goes Into an Artery?
Accidental arterial cannulation during central line insertion, though relatively infrequent (occurring in up to 5% of cases), carries significant risks because arteries transport oxygenated blood under high pressure away from the heart. Unlike veins, which carry deoxygenated blood back to the heart under lower pressure, arteries are not designed to accommodate central catheters and the medications typically administered through them.
Immediate Indications of Arterial Cannulation
Recognizing arterial cannulation early is crucial for preventing severe outcomes. Key indicators include:
- Bright Red, Pulsatile Blood: When the catheter is accessed, blood will appear bright red and spurt out in a pulsatile manner, synchronized with the patient's heartbeat. This contrasts sharply with venous blood, which is typically darker red and flows steadily without pulsation.
- High Pressure: Attempts to flush the line may meet significant resistance due to the arterial pressure.
- Pressure Transducer Readings: If connected to a pressure transducer, the waveform will show an arterial pressure tracing (high systolic/diastolic pressures) rather than the low venous pressure waveform.
Potential Complications of Arterial Cannulation
The high pressure within arteries and the potential for direct vessel injury can lead to a variety of severe complications. These complications include, but are not limited to:
| Complication | Description | Potential Severity |
|---|---|---|
| Hematoma | A collection of blood outside blood vessels, often causing swelling, pain, and bruising. In high-pressure arteries, these can be large and rapidly expanding, potentially compressing surrounding structures like the airway. | Moderate to Severe |
| Hemothorax | An accumulation of blood in the pleural cavity (the space between the chest wall and the lungs), which can compress the lung and impair breathing. | Severe, Life-threatening |
| Pseudoaneurysm | A contained rupture of an artery where blood leaks out but is confined by surrounding tissue, forming a pulsating mass that resembles an aneurysm. It carries a risk of rupture or thrombus formation. | Severe |
| Stroke | Occurs if a clot forms within the injured artery and travels to the brain, or if the arterial injury directly compromises blood flow to the brain, leading to neurological deficits. | Severe, Life-threatening |
| Arteriovenous (AV) Fistula | An abnormal, direct connection between an artery and a vein, bypassing the capillaries. This can lead to increased blood flow through the fistula, potentially causing heart strain or distal ischemia. | Moderate to Severe |
Specific Risks with Carotid Artery Cannulation
Accidental damage to the carotid arteries, which supply blood to the brain, is particularly dangerous. This type of arterial cannulation has been linked to a significantly higher risk of neurological complications, including stroke, due to the direct impact on cerebral blood supply.
Why Arterial Cannulation is Serious
Beyond the immediate injury, inserting a central line into an artery poses several critical problems:
- High-Pressure Bleeding: Arteries are high-pressure vessels. Even a small puncture can lead to significant and rapid blood loss, or the formation of large hematomas that can compromise vital structures.
- Inappropriate Medication Delivery: Many medications administered via central lines (e.g., certain vasopressors, hyperosmolar solutions, vesicants) are highly irritating to arterial walls or can cause severe vasoconstriction and ischemia if injected directly into an artery. This can lead to limb loss or severe tissue damage.
- Risk of Air Embolism: While more common with venous access, air can still be entrained during arterial line removal, though the high pressure generally makes this less likely to be fatal compared to venous air embolism unless the air travels to critical areas like the brain.
Prevention and Management
Preventing arterial cannulation relies on careful technique and confirmation methods. If it does occur, prompt recognition and appropriate management are essential.
Prevention Strategies:
- Ultrasound Guidance: Using ultrasound in real-time during insertion allows for visualization of both the vein and artery, helping to ensure the needle is correctly aimed at the vein and avoiding accidental arterial puncture.
- Pressure Transduction/Blood Gas Analysis: Confirming venous placement by attaching a pressure transducer to see a venous waveform, or by drawing a blood sample and performing a blood gas analysis to confirm venous oxygen and carbon dioxide levels (venous blood will have lower oxygen and higher carbon dioxide than arterial blood).
- Experienced Operators: Procedures should ideally be performed by experienced clinicians.
Management Steps:
- Immediate Recognition: Recognize the pulsatile flow of bright red blood or high-pressure readings.
- Catheter Removal (Careful): If arterial cannulation is confirmed or highly suspected, the catheter must be removed immediately and carefully.
- Direct Pressure: Apply firm, continuous pressure to the insertion site for an extended period (typically 10-20 minutes, or longer if on anticoagulants) to prevent hematoma formation and achieve hemostasis.
- Monitoring: Monitor the patient closely for signs of hematoma expansion, neurological deficits (especially with carotid involvement), or other complications.
- Imaging: Consider immediate imaging (e.g., ultrasound, CT angiography) to assess the extent of arterial injury, rule out pseudoaneurysm, or identify other complications.
- Surgical Consultation: In cases of significant bleeding, large hematoma, pseudoaneurysm formation, or evidence of ischemia, vascular surgery consultation is imperative.
