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Difficulty: MediumPharmacological and Parenteral Therapies

A nurse is preparing to draw a diagnostic blood specimen from a client's central venous catheter (CVC) using the syringe method. Arrange the following actions in the correct procedural sequence. All options must be used.

  1. 1Scrub the needleless connector of the catheter with an appropriate antiseptic swab.
  2. 2Flush the catheter lumen with 10 mL of preservative-free 0.9% sodium chloride.
  3. 3Withdraw and discard a 5 mL waste sample of blood from the catheter lumen.
  4. 4Attach a new sterile syringe and withdraw the required volume of blood for the specimen.
  5. 5Flush the catheter vigorously with 10 to 20 mL of 0.9% sodium chloride using a pulsatile method.

Answer

The correct sequence is to disinfect the hub, flush the line to check patency, withdraw a waste sample, draw the actual specimen, and finally flush the line to clear residual blood.
When drawing blood from a central venous catheter, maintaining sterility and ensuring an uncontaminated sample are paramount. Scrubbing the hub is the first step to prevent central line-associated bloodstream infections. Flushing the line confirms patency. The critical step of withdrawing a waste sample ensures that the subsequent diagnostic sample is not diluted by the normal saline flush or residual medications. After obtaining the specimen, a larger volume flush is required to completely clear the lumen of blood, preventing fibrin buildup and occlusion.

Step-by-Step Solution

1
Scrub the needleless connector of the catheter with an appropriate antiseptic swab.
The entry point is disinfected.
This prevents the introduction of microorganisms into the client's bloodstream and reduces the risk of central line-associated bloodstream infections (CLABSI).
2
Flush the catheter lumen with 10 mL of preservative-free 0.9% sodium chloride.
Catheter patency is confirmed.
Flushing ensures the line is open and clears previously infused fluids that could mix with the blood.
3
Withdraw and discard a 5 mL waste sample of blood from the catheter lumen.
The flush solution is removed from the line.
Discarding the initial blood prevents dilution and contamination of the diagnostic specimen by the saline.
4
Attach a new sterile syringe and withdraw the required volume of blood for the specimen.
The diagnostic sample is obtained.
This sample will accurately reflect the client's physiological laboratory values without interference from flush solutions.
5
Flush the catheter vigorously with 10 to 20 mL of 0.9% sodium chloride using a pulsatile method.
Residual blood is cleared from the line.
A final flush prevents blood from pooling and clotting in the catheter, maintaining its long-term patency.

Key Concept

Central Venous Catheter Blood Specimen Collection Procedure
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Topics

Pharmacological and Parenteral Therapies

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