Is blood supposed to be drawn from midline (peripherally inserted central catheter) catheters?

Blood Collection from Midline Catheters

Blood should not be routinely drawn from midline catheters due to increased risk of complications including thrombosis and infection.

Understanding Midline Catheters

Midline catheters are peripheral venous access devices that are longer than standard peripheral IV catheters but do not extend into central veins like peripherally inserted central catheters (PICCs). They typically terminate in the basilic or brachial veins of the upper arm.

Key Considerations for Blood Collection

• Infection Risk: Drawing blood from midline catheters increases the risk of catheter-related bloodstream infections (CRBSI) by potentially introducing contaminants during the access procedure 1.

• Thrombosis Risk: Midlines have a higher risk of superficial venous thrombosis compared to PICCs (odds ratio 2.30; 95% CI, 1.48-3.57) 2, and blood sampling can further increase this risk by causing mechanical trauma to the vessel wall.

• Catheter Occlusion: Repeated blood draws can lead to catheter occlusion, reducing the functional lifespan of the device 1.

Evidence-Based Recommendations

When Blood Collection is Necessary

If blood collection from a midline catheter is absolutely necessary (such as in cases of difficult venous access), follow these guidelines:

1. Blood Culture Collection:

   • If catheter-related bloodstream infection (CRBSI) is suspected, collect paired blood cultures from both the midline catheter and a peripheral vein 1.
   • If peripheral access is impossible, draw samples from different catheter lumens (if available) at different times 1.

2. Technique for Blood Collection:

   • Use strict aseptic technique with chlorhexidine-alcohol preparation 1.
   • Allow adequate drying time for the antiseptic to prevent blood contamination 1.
   • After collection, flush thoroughly with saline to prevent occlusion 1.

Preferred Alternatives

• Peripheral Venepuncture: Whenever possible, collect blood samples from peripheral veins rather than from the midline catheter 1.

• Central Venous Access: For patients requiring frequent blood sampling, consider a central venous catheter rather than a midline, especially for long-term use 1.

Complications of Midline Blood Collection

• Thrombosis: Midline catheters have been associated with higher rates of superficial venous thrombosis compared to PICCs 3.

• Infection: While midlines generally have lower CRBSI rates than PICCs for short-term use 4, any manipulation of the line increases infection risk.

• Mechanical Complications: Recent research shows midlines have a higher overall complication rate compared to PICCs (IRR 2.37; 95% CI, 1.12-5.02) 5.

Clinical Pitfalls to Avoid

• Routine Use for Blood Collection: Avoid using midlines as a routine blood collection site, even when they appear convenient 1.

• Inadequate Flushing: Always flush with saline after any access of the midline to maintain patency 1.

• Ignoring Signs of Complications: Monitor for signs of thrombophlebitis, infection, or occlusion, especially after blood collection 6.

By following these evidence-based guidelines, healthcare providers can minimize risks associated with midline catheters while ensuring appropriate vascular access for necessary therapies.