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Difficulty: HardPharmacological and Parenteral Therapies

A client with severe sepsis is receiving a continuous intravenous (IV) infusion of norepinephrine at 0.05 mcg/kg/min0.05\text{ mcg/kg/min} through the proximal lumen of a double-lumen central venous catheter (CVC). The healthcare provider orders an intermittent IV infusion of piperacillin/tazobactam 3.375 g3.375\text{ g} diluted in 100 mL100\text{ mL} of normal saline to be administered over 30 minutes30\text{ minutes}. A drug reference indicates that piperacillin/tazobactam is physically incompatible with norepinephrine. Which of the following is the most appropriate action by the nurse?

  1. Initiate the piperacillin/tazobactam infusion through the distal lumen of the CVC using an infusion pump set at 200 mL/hr200\text{ mL/hr}.Answer
  2. B
    Connect the piperacillin/tazobactam infusion to the lowest Y-site on the norepinephrine tubing and set the infusion pump to 100 mL/hr100\text{ mL/hr}.
  3. C
    Pause the norepinephrine infusion, flush the proximal lumen with normal saline, infuse the piperacillin/tazobactam at 200 mL/hr200\text{ mL/hr}, and then restart the norepinephrine.
  4. D
    Establish a new peripheral IV access to administer the piperacillin/tazobactam because incompatible medications cannot safely share the same CVC.

Answer

The nurse should initiate the antibiotic infusion through the distal lumen of the CVC at a rate of 200 mL/hr200\text{ mL/hr}.
A double-lumen central venous catheter contains two structurally separate internal lumens that do not mix within the catheter, allowing physically incompatible medications to be administered simultaneously. The medications exit into the high-flow environment of the superior vena cava, where immediate hemodilution prevents precipitation. The correct IV pump rate is mathematically derived by dividing the total volume (100 mL100\text{ mL}) by the infusion time in hours (0.5 hours0.5\text{ hours}), which equals 200 mL/hr200\text{ mL/hr}.

Step-by-Step Solution

1
Evaluate the design and safety properties of a double-lumen central venous catheter.
A double-lumen CVC contains two distinct, parallel internal pathways that exit at different points in the bloodstream.
This allows for the simultaneous administration of physically incompatible medications without them ever mixing inside the catheter.
2
Calculate the correct intravenous infusion rate for the piperacillin/tazobactam.
Divide the total volume by the time in hours: 100 mL÷0.5 hours=200 mL/hr100\text{ mL} \div 0.5\text{ hours} = 200\text{ mL/hr}.
IV pumps must be programmed in mL/hr\text{mL/hr} to safely deliver the medication over the prescribed 3030-minute timeframe.
3
Assess the clinical implications of the continuous norepinephrine infusion.
Norepinephrine is a critical, short-acting vasopressor. It must not be paused for the antibiotic infusion.
Interrupting a vasopressor in a septic client will rapidly lead to profound, life-threatening hypotension.

Key Concept

Administration of physically incompatible medications via multi-lumen central venous catheters and calculating accurate IV infusion pump rates.
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Topics

Pharmacological and Parenteral Therapies

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