Should normal saline be added to the piggyback infusion?

Should Normal Saline Be Added to the Piggyback Infusion?

Yes, adding normal saline to flush piggyback (IVPB) infusions is recommended to ensure complete medication delivery, particularly for small-volume infusions where residual medication remains in the administration set and bag after the primary infusion completes.

Rationale for Normal Saline Flush

When administering intermittent secondary IV infusions (piggyback), a significant amount of medication remains in the tubing and bag after the infusion appears complete. Research demonstrates that without an ancillary flushing technique, substantial drug loss occurs, potentially compromising therapeutic efficacy 1.

Key Clinical Considerations

For Medication Delivery:

• Residual medication in the secondary administration set and bag represents a clinically significant volume
• This is particularly critical for small-volume IVPB infusions where the proportion of residual drug is higher
• A standardized flushing technique optimizes drug delivery and ensures the patient receives the intended dose 1

For Emergency Medications: Multiple guidelines support normal saline as the preferred flush solution in critical situations:

• Endotracheal drug administration: When medications are given via endotracheal tube during resuscitation, they should be followed with at least 5 mL of normal saline and 5 consecutive positive-pressure ventilations 2
• Anaphylaxis management: Normal saline is specifically recommended for IV access and fluid replacement, with aqueous epinephrine diluted in 10 mL of normal saline for IV administration 3
• Pediatric resuscitation: All endotracheal medications require flushing with 5 mL of normal saline followed by 5 ventilations 2

Practical Implementation

Standard technique for IVPB administration:

1. Allow the piggyback infusion to complete
2. Add normal saline to the secondary bag (typically 20-50 mL depending on tubing volume)
3. Infuse the saline flush to clear residual medication from the tubing
4. This ensures complete medication delivery without drug loss

Volume considerations:

• The flush volume should be sufficient to clear the entire secondary administration set
• Standard secondary tubing holds approximately 20-30 mL
• Adjust flush volume based on tubing length and patient fluid tolerance

Important Caveats

• For patients with severe fluid restrictions (congestive heart failure, renal disease), use the minimum effective flush volume while still ensuring complete drug delivery
• Document the flush volume as part of total fluid intake
• This recommendation applies to standard medication administration; emergency resuscitation scenarios follow specific protocols outlined above

The evidence consistently supports using normal saline as the preferred solution for flushing IV lines and ensuring complete medication delivery across multiple clinical contexts 3, 2, 3, 1.