Push-Pull Method for Blood Draws from Pediatric Central Venous Catheters
Direct Recommendation
The push-pull method is a safe and reliable waste-free blood sampling technique for pediatric central venous catheters that should be implemented as standard practice in the PICU to reduce iatrogenic blood loss and prevent transfusion-related complications. 1
Evidence Supporting the Push-Pull Method
The push-pull technique has been validated specifically for pediatric CVC blood sampling through evidence-based practice implementation in the PICU setting 1. This method eliminates the traditional discard volume, thereby significantly reducing sampling-related blood loss—a critical concern in pediatric patients who are particularly vulnerable to iatrogenic anemia 1.
Key Implementation Points
The technique involves:
- Drawing blood into the syringe and immediately pushing it back into the catheter to mix with the dead space volume 1
- Repeating this push-pull action several times to ensure adequate mixing 1
- Then drawing the sample for laboratory testing without any discard volume 1
This approach has been demonstrated to provide accurate laboratory results while protecting pediatric patients from cumulative blood loss that can necessitate transfusions 1.
Critical CVC Management Considerations
Dedicated Lumen for Specific Uses
When using CVCs for blood sampling in pediatric patients, one lumen should be dedicated exclusively to parenteral nutrition if PN is being administered 2. However, for routine monitoring in patients on long-term PN, blood sampling via CVC is acceptable when full aseptic protocol is followed 2.
Multi-Lumen Catheter Risks
Multi-lumen catheters carry increased infection risk (10-20% sepsis rate) compared to single-lumen catheters (0-5% sepsis rate) 2. When multi-lumen CVCs are necessary, strict protocols must be maintained: one lumen reserved exclusively for its designated purpose, no blood sampling from PN lumens during active infusion, and avoidance of blood transfusion or central venous pressure measurement through dedicated lumens 2.
Common Pitfalls to Avoid
Do not routinely use the CVC for blood sampling if it compromises line integrity or increases manipulation frequency, as this elevates infection risk 2. The exception is patients requiring long-term PN where routine monitoring necessitates CVC access, provided strict aseptic technique is maintained 2.
Avoid using CVCs with catheter-to-vessel diameter ratios >0.45, as this increases thrombosis risk 3. Right-sided insertion is strongly preferred over left-sided (relative risk of thrombosis 4.4 for left-sided) 3.
Age-Specific Considerations
Pediatric CVC complications are closely linked to age, body size, and immune status 4. Younger children and infants face higher complication rates and require more careful monitoring during blood sampling procedures 4. The bimodal age distribution of central venous thrombosis—with peaks in the neonatal period and adolescence—means heightened vigilance is needed in these populations 3.
Safety Profile
The push-pull protocol has been evaluated and found safe for standard PICU use across different CVC types 1. This waste-free approach directly addresses the major source of blood loss in critically ill children while maintaining laboratory accuracy 1.