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Difficulty: HardPharmacological and Parenteral Therapies

A nurse is preparing to draw a blood specimen from a client's multi-lumen central venous catheter (CVC). A continuous intravenous infusion of 0.9% sodium chloride is currently running through a different lumen of the catheter. Arrange the following steps in the correct chronological order to obtain the blood sample safely and prevent laboratory result contamination.

  1. 1Pause the continuous intravenous infusion on the other lumen for at least 1 to 2 minutes.
  2. 2Scrub the needleless connector of the designated sampling lumen with an antiseptic swab.
  3. 3Flush the sampling lumen to verify patency, then withdraw and discard 5 to 10 mL of blood.
  4. 4Attach a new sterile syringe and withdraw the required volume of blood for the laboratory specimen.
  5. 5Flush the sampling lumen with 10 to 20 mL of 0.9% sodium chloride and restart the paused infusion.

Answer

The correct sequence is to first pause the active infusion, then scrub the hub, verify patency and discard the dead space fluid, draw the actual sample, and finally flush the line and restart the infusion.
The correct sequence ensures patient safety, prevents central line-associated bloodstream infections (CLABSI), and guarantees the integrity of the laboratory specimen. Pausing other infusions is the critical first step to prevent hemodilution. Aseptic technique (scrubbing the hub) must precede any line access. A discard sample is necessary to remove the fluid sitting in the catheter's dead space before obtaining the actual diagnostic sample. Finally, the line must be flushed to prevent clotting, and the paused infusion must be restarted.

Step-by-Step Solution

1
Pause the continuous intravenous infusion on the other lumen for at least 1 to 2 minutes.
The flow of intravenous fluids into the central circulation is temporarily halted.
This prevents hemodilution and ensures the drawn blood sample is not contaminated by the infusing fluids.
2
Scrub the needleless connector of the designated sampling lumen with an antiseptic swab.
The entry point for the syringe is disinfected.
Strict asepsis prevents the introduction of pathogens into the client's central bloodstream, preventing infection.
3
Flush the sampling lumen to verify patency, then withdraw and discard 5 to 10 mL of blood.
The catheter is confirmed to be patent, and the dead space is cleared of residual fluids.
Discarding the initial blood volume ensures that the subsequent sample consists of pure circulating blood rather than flush solution or residual fluids.
4
Attach a new sterile syringe and withdraw the required volume of blood for the laboratory specimen.
An uncontaminated diagnostic sample is successfully collected.
Using a fresh syringe ensures the actual specimen is accurately obtained for laboratory analysis.
5
Flush the sampling lumen with 10 to 20 mL of 0.9% sodium chloride and restart the paused infusion.
The catheter lumen is cleared of residual blood, and the client's continuous therapy is resumed.
A thorough flush prevents fibrin buildup and catheter occlusion, while restarting the infusion ensures therapeutic continuity.

Key Concept

Central Venous Catheter (CVC) Blood Specimen Collection (Discard Method)
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Topics

Pharmacological and Parenteral Therapies

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