Which drug should be used for rinsing the syringe before taking blood sample for ABG analysis?

Appeared in: Combined AIIMS - 2020 (Jodhpur, Bhopal, Patna, Raipur)

Explanation

Heparin is an anticoagulant used both in vivo (in the body) and in vitro (in the lab/syringe).
Its primary function in this context is to prevent the blood sample from clotting, which is essential for an accurate Arterial Blood Gas (ABG) analysis.
Commercially prepared ABG syringes are pre-heparinized for this purpose.
The other options are vasoactive drugs used for cardiovascular support and have no anticoagulant properties.

Option B: Dobutamine is a beta-1 adrenergic agonist, a type of inotropic agent. It is used to increase the contractility of the heart, primarily in cases of cardiogenic shock or severe heart failure.
Option C: Dopamine is a catecholamine that acts as a vasopressor and inotrope. Its effects are dose-dependent, and it is used to manage low blood pressure, low heart rate, and cardiac arrest.
Option D: Adrenaline (epinephrine) is a potent hormone and neurotransmitter used in emergencies like cardiac arrest, anaphylaxis, and severe asthma attacks. It is a powerful vasopressor and cardiac stimulant.

Clinical Relevance

Nursing practice connection: Knowing Anticoagulation for Arterial Blood Gas (ABG) sample collection helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Accurate ABG results are critical for diagnosing and managing life-threatening conditions like respiratory failure, metabolic acidosis/alkalosis, and septic shock. A clotted sample delays diagnosis and treatment.
Improper technique, such as leaving excess heparin in the syringe, can dilute the sample and falsely lower the pH and bicarbonate levels, leading to misdiagnosis.
What if? If a patient is already on systemic anticoagulant therapy (like a heparin infusion), the nurse must apply pressure to the puncture site for a longer duration (10-15 minutes) to ensure hemostasis and prevent compartment syndrome.

How to Approach the Question

First, identify the core purpose of the action described in the question: rinsing a syringe for an ABG sample.
Recognize that the goal is to prevent the blood from clotting, which would ruin the sample.
Therefore, the question is asking you to identify an anticoagulant from the list of options.
Review the options and classify each drug. Heparin is a well-known anticoagulant.
Dobutamine, Dopamine, and Adrenaline are all catecholamines/sympathomimetics used for cardiovascular support. Eliminate them as they do not prevent clotting.

Concept Tested & Keywords

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E6 Pharmacology Nurses Shanbhag 3e p. 226-228

E6 Pharmacology Nursing Lilley 11e Part 1 p. 318-320

Practise the full Combined AIIMS - 2020 (Jodhpur, Bhopal, Patna, Raipur)

Attempt every question from this paper in a timed mock, then review the full solution for each one.