Diluted venous blood appears arterial: implications for central venous cannulation

Area of Science:

• Medical Procedures
• Vascular Access
• Patient Safety

Background:

• Central venous access is a common medical procedure.
• Arterial puncture is a potential complication during central venous catheterization.
• Distinguishing arterial from venous blood is critical for safe practice.

Purpose of the Study:

• To highlight the diagnostic challenge of arterial puncture during central venous access.
• To explain a common method for identifying inadvertent arterial puncture.
• To describe how saline can obscure the signs of arterial puncture.

Main Methods:

• Observational analysis of central venous access procedures.
• Review of blood aspiration characteristics.
• Assessment of blood color changes upon dilution.

Main Results:

• Inadvertent arterial puncture typically presents with bright red aspirated blood.
• Diluting aspirated blood with saline can alter its color.
• Dusky venous blood can appear bright red after saline dilution, mimicking arterial blood.

Conclusions:

• The bright red color of aspirated blood is a key indicator of arterial puncture.
• Saline dilution can misleadingly change the color of venous blood, potentially masking arterial puncture.
• Clinicians must be aware of this color change to avoid misinterpreting blood samples during central venous access procedures.