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Difficulty: Very hardPharmacological and Parenteral Therapies

A telemetry nurse is caring for a client who suddenly develops paroxysmal supraventricular tachycardia (SVT). The client's heart rate is 205 beats/min, and blood pressure is 114/72 mm Hg. The client is alert and reports feeling a "racing heart." The client has a double-lumen central venous catheter (CVC) in the right internal jugular vein. The proximal lumen is infusing continuous normal saline, and the distal lumen is capped. No peripheral intravenous access is available. The healthcare provider is at the bedside and verbally orders, "Administer adenosine 6 mg rapid IV push stat."

What is the most appropriate action by the nurse?

  1. Clarify the prescription with the provider to reduce the adenosine dose to 3 mg due to the central venous administration routeAnswer
  2. B
    Administer the 6 mg of adenosine rapidly through the capped distal lumen, follow with a 20 mL rapid saline flush, and elevate the client's right arm
  3. C
    Question the prescription for adenosine and advocate for immediate synchronized cardioversion due to the severity of the tachycardia
  4. D
    Administer the 6 mg of adenosine slowly over 1 to 2 minutes through the distal lumen to minimize the risk of a prolonged asystolic pause

Answer

The nurse must clarify the order with the provider to reduce the adenosine dose from 6 mg to 3 mg because the medication will be administered via a central venous catheter.
The correct answer identifies that the standard initial dose of adenosine (6 mg) must be reduced when given via a central line. Adenosine causes transient atrioventricular (AV) node block to terminate SVT and has a half-life of less than 10 seconds. The standard 6 mg dose is calculated for peripheral IV administration, factoring in natural degradation as the drug travels up the arm to the heart. When administered via a central venous catheter (CVC) that terminates in the superior vena cava, the drug reaches the cardiac tissue almost instantly and in a much higher concentration. According to resuscitation guidelines, the initial adenosine dose must be reduced by half (to 3 mg) for central administration to prevent profound, prolonged asystole or high-degree heart blocks. The nurse must act as a patient advocate and clarify this order with the provider.

Step-by-Step Solution

1
Assess the client's hemodynamic stability and presenting rhythm.
The client is in SVT but remains hemodynamically stable (alert, blood pressure 114/72 mm Hg), making pharmacological intervention appropriate over electrical cardioversion.
Differentiating between stable and unstable SVT dictates whether the client receives medications (adenosine) or immediate synchronized cardioversion.
2
Evaluate the prescribed medication dose against the available intravenous access route.
The provider ordered 6 mg of adenosine, which is the standard peripheral dose. However, the client only has a central venous catheter (CVC).
Medication pharmacokinetics, particularly for rapidly acting cardiac drugs, can change drastically based on the route of administration.
3
Determine the appropriate dosage adjustment for central line administration.
Resuscitation guidelines require reducing the initial adenosine dose to 3 mg when administered centrally.
Central administration bypasses peripheral degradation, delivering the medication to the heart instantly. A full 6 mg central dose drastically increases the risk of prolonged asystole.
4
Formulate the safest nursing action based on the findings.
The nurse must hold the medication and clarify the order with the provider to reduce the dose to 3 mg before administration.
Nurses must verify that all components of a medication prescription are safe and appropriate for the client's specific clinical situation, acting as the final safety checkpoint.

Key Concept

Pharmacokinetics of Adenosine via Central Venous Access
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Topics

Pharmacological and Parenteral Therapies

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