What can be given through an arterial line?

While an estimated one-third of intensive care unit (ICU) patients in the United States receive an arterial line for monitoring, it is critical to understand what can be given through an arterial line and what should be strictly avoided due to severe risks. The primary use of an arterial line is for monitoring, not for medication administration.

Quick Summary

This guide explains the limited and specific fluids that can be infused via an arterial line. It details the severe risks of inappropriate medication administration and outlines critical safety protocols to prevent dangerous errors in clinical practice.

Key Points

• Limited Use: Arterial lines are primarily for monitoring blood pressure and drawing blood samples, not for general medication administration.

• High Risk: Injecting most medications into an artery can cause immediate and severe complications, including arterial spasm, thrombosis, tissue necrosis, and potential limb loss.

• Saline Flushes Only: The only standard fluids administered via an arterial line are saline-based solutions to maintain catheter patency and prevent clotting.

• Strict Exceptions: Specialized procedures like targeted intra-arterial chemotherapy are exceptions, but these are controlled interventions performed by experts.

• Critical Safety: Preventing errors relies on meticulous protocols, including clear labeling, color-coding, use of dedicated equipment, and thorough staff education to distinguish arterial from venous access.

An arterial line, often called an 'art line,' is a thin, flexible catheter inserted into an artery, typically in the wrist (radial artery), groin (femoral artery), or foot (dorsalis pedis artery). The primary purpose of this invasive device is not to deliver medication systemically, but rather for continuous, beat-to-beat monitoring of blood pressure and for obtaining frequent arterial blood samples for lab analysis, such as blood gas measurements. The distinction between arterial and venous access is fundamental to safe patient care, as the consequences of using an arterial line for standard medication infusion can be catastrophic.

The Limited Scope of Arterial Line Infusions

For the vast majority of clinical scenarios, the only fluid administered through an arterial line is a slow, continuous flush solution. This is essential for preventing the catheter from becoming clotted, which would compromise its function.

Approved Infusions:

• Normal Saline (0.9% Sodium Chloride): This is the standard flush solution used to maintain the patency of the line. It is delivered at a very slow, continuous rate via a pressurized system.
• Heparinized Saline: Some protocols may call for a low-dose heparin solution mixed with saline, though studies have indicated this does not significantly reduce the risk of catheter thrombosis. Healthcare facilities must have clear, standardized policies regarding its use.

These fluids are not administered for their systemic effects, but for the local mechanical purpose of keeping the catheter clear. Any other fluid or medication, with a few highly specialized exceptions, is considered dangerous if administered through an arterial line.

The Severe Dangers of Inappropriate Intra-Arterial Injection

Injecting most medications directly into an artery can lead to severe and immediate complications. Unlike veins, arteries carry high-pressure blood directly to the capillaries supplying the tissues and extremities. When a drug is injected into this system, it can cause severe arterial spasm, inflammation of the arterial lining (endarteritis), and the formation of blood clots (thrombosis).

This can result in a chain reaction of devastating events, including:

• Severe Pain: Intense burning pain is a common initial symptom, often radiating from the injection site to the fingers or toes.
• Tissue Ischemia and Necrosis: The blocked or spasming artery starves the downstream tissues of oxygenated blood, leading to tissue death (necrosis).
• Gangrene and Limb Loss: In severe cases, extensive tissue necrosis can lead to gangrene, which may necessitate amputation of the affected limb or digits.
• Compartment Syndrome: Swelling and inflammation can build up pressure within a muscle compartment, further reducing blood flow and causing irreversible damage.

Medications with High Risk for Intra-Arterial Injury

• Barbiturates (e.g., Thiopental): Historically known to cause severe injury due to precipitation of crystals upon injection.
• Benzodiazepines (e.g., Diazepam): Can lead to significant tissue necrosis.
• Hypertonic Solutions (e.g., Concentrated Potassium Chloride): Highly irritating to arterial walls, causing spasm and damage.
• Certain Antibiotics: Some formulations can be highly irritating and cause thrombosis when administered arterially.
• Vasoactive Medications (e.g., Dopamine, Epinephrine): While these are often used in critical care, their intra-arterial injection can cause profound vasoconstriction and ischemia in the limb.

Specialized Intra-Arterial Delivery: The Exceptions

In rare, highly specialized medical procedures, medications are deliberately delivered via an intra-arterial route to achieve a localized, high-concentration effect.

• High-Dose Chemotherapy: In oncology, high doses of chemotherapy can be delivered intra-arterially to target specific tumors, such as in the head and neck, to maximize drug concentration at the site while limiting systemic side effects.
• Intra-arterial Thrombolysis: For acute arterial thrombosis, a clot-busting drug (thrombolytic) can be infused directly into the affected artery to dissolve the clot and restore blood flow. This is a complex procedure performed by specialists.
• Interventional Radiology: Certain procedures in interventional radiology may involve injecting contrast dye or medications directly into arteries to visualize or treat a specific area. These are carefully planned and controlled interventions.

Critical Safety Protocols for Arterial Line Management

To prevent potentially fatal medication errors involving arterial lines, healthcare institutions have established strict protocols:

• Clear Labeling and Color-Coding: Arterial lines and their tubing should be clearly and distinctly labeled to avoid confusion with venous access lines. Some facilities use specific color-coding (e.g., red for arterial) to distinguish them.
• Dedicated Equipment: Standard intravenous tubing should never be connected to an arterial line. Arterial lines require specific, non-compliant tubing and transducers.
• Dual Verification: Before any fluid is connected to an arterial line, a dual-verification process should be performed by two qualified healthcare providers.
• Staff Education and Awareness: All staff involved in patient care must receive regular training on the function, risks, and safety protocols for arterial lines. This is especially crucial for junior staff.
• Monitoring Distal Perfusion: The extremity distal to the arterial line insertion site should be frequently monitored for signs of ischemia, such as coolness, mottling, or pain.
• Use of Different Connectors: The universal compatibility of Luer-lock connectors has been identified as a cause of wrong-route errors. Future medical device standards aim to use non-interchangeable connectors for different delivery systems to prevent misconnections.

Comparison: Arterial vs. Venous Access

Feature	Arterial Line	Venous Line
Primary Purpose	Continuous blood pressure monitoring; frequent blood sampling	Medication administration; fluid infusion
Blood Flow	Carries oxygenated blood away from the heart, under high pressure	Carries deoxygenated blood toward the heart, under low pressure
Location	Radial, femoral, or brachial arteries	Peripheral veins (arms, hands); Central veins (neck, chest)
Medication Risk	Extremely high risk of tissue ischemia, necrosis, and limb loss	Safe for most medications, but risk if extravasation occurs
Typical Infusions	Normal saline flush only	Medications, fluids, blood products, nutrition
Monitoring	Provides a real-time, beat-to-beat pressure waveform	Used to monitor fluid volume and central venous pressure (if central)

Conclusion

An arterial line is a vital monitoring tool in critical care, providing accurate, continuous blood pressure data and enabling frequent blood sampling without repeated needle sticks. However, it is not a route for general medication administration. The only fluids that should typically be given through an arterial line are saline-based flushes to prevent clotting. Administering medications through this route is exceptionally dangerous and can lead to severe and irreversible harm to the patient. Adherence to strict protocols, including proper labeling, dedicated equipment, and comprehensive staff training, is essential for ensuring patient safety and preventing catastrophic errors related to intra-arterial injection. Healthcare providers must remain vigilant and continuously educated on this critical aspect of pharmacology in the intensive care setting.

Visit the AHRQ PSNet for further details on preventing misconnections leading to arterial thrombosis.

Frequently Asked Questions

What is an arterial line used for, and how is it different from an IV?

An arterial line is a catheter placed in an artery primarily for continuous, accurate blood pressure monitoring and frequent blood sampling. It differs from an intravenous (IV) line, which is placed in a vein and used for administering medications and fluids.

Why is it so dangerous to inject medication into an arterial line?

Injecting medication into an artery can cause direct injury to the vessel, arterial spasm, and blood clots. This can restrict blood flow to the downstream tissues, causing severe pain, tissue death (necrosis), and potentially requiring amputation.

What types of medication are particularly dangerous to give intra-arterially?

Highly dangerous medications include barbiturates (like thiopental), benzodiazepines (like diazepam), hypertonic solutions, and certain antibiotics. These can cause severe vascular damage and thrombosis.

Are there any situations where medication is intentionally given intra-arterially?

Yes, in rare, specialized cases. High-dose chemotherapy can be delivered intra-arterially to target specific tumors, and thrombolytics can be infused directly into an artery to dissolve a clot. These are not routine procedures.

What happens if a medication error occurs and a drug is mistakenly injected into an arterial line?

The patient may experience intense pain, followed by signs of ischemia in the limb (coolness, mottling, sensory changes). The response requires immediate medical intervention, including consultation with specialists like vascular surgeons, to attempt to restore blood flow.

What safety measures are in place to prevent accidental injections into arterial lines?

Key safety measures include using dedicated equipment with distinct connectors, clear and prominent labeling and color-coding of arterial lines, and a dual-verification process before connecting any fluid. Regular staff training is also essential.

What is the only fluid typically administered through an arterial line?

The only fluid routinely administered through an arterial line is a continuous, slow infusion of normal saline (0.9% sodium chloride) to prevent the catheter from clotting and to maintain its patency.