Podcast
Questions and Answers
What is the primary action of propranolol?
What is the primary action of propranolol?
- Enhance vagal tone on the heart
- Stimulate cardiac β-receptors
- Release adrenaline from adrenal glands
- Antagonize cardiac β-receptors (correct)
What occurs after the administration of a high dose of adrenaline?
What occurs after the administration of a high dose of adrenaline?
- Decreased heart rate
- Increased cardiac excitability (correct)
- Reduced arrhythmia risk
- Enhanced vagal inhibition
Which of the following sequences for drug administration is correct?
Which of the following sequences for drug administration is correct?
- Adrenaline, Propranolol, Atropine (correct)
- Atropine, Propranolol, Adrenaline
- Atropine, Adrenaline, Propranolol
- Propranolol, Atropine, Adrenaline
What is the expected effect on heart rate after administering propranolol following adrenaline?
What is the expected effect on heart rate after administering propranolol following adrenaline?
What is the effect of atropine when administered after propranolol?
What is the effect of atropine when administered after propranolol?
Which of the following descriptions best fits the action of adrenaline?
Which of the following descriptions best fits the action of adrenaline?
How does the heart rate respond during the first administration of adrenaline compared to the second administration?
How does the heart rate respond during the first administration of adrenaline compared to the second administration?
What is indicated by the presence of arrhythmia after administering adrenaline?
What is indicated by the presence of arrhythmia after administering adrenaline?
Flashcards
What is adrenaline's effect on heart rate and rhythm?
What is adrenaline's effect on heart rate and rhythm?
Adrenaline stimulates both alpha and beta receptors in the heart. It is a powerful stimulant of heart rate and contractility, potentially leading to irregular rhythms.
How does propranolol counteract adrenaline's effects on the heart?
How does propranolol counteract adrenaline's effects on the heart?
Propranolol blocks beta receptors in the heart, effectively slowing down heart rate and reducing the risk of arrhythmias caused by adrenaline.
What is atropine's effect on heart rate?
What is atropine's effect on heart rate?
Atropine blocks muscarinic receptors in the heart, weakening the inhibitory influence of the vagus nerve. This effectively increases heart rate.
Why is rapid adrenaline administration important?
Why is rapid adrenaline administration important?
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Why is slow propranolol administration important?
Why is slow propranolol administration important?
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What is the purpose of the ECG in this experiment?
What is the purpose of the ECG in this experiment?
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Why is adrenaline administered multiple times?
Why is adrenaline administered multiple times?
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What is the purpose of the specific sequence of medication administration?
What is the purpose of the specific sequence of medication administration?
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Study Notes
Effect of Propranolol on Adrenaline-Induced Arrhythmia
- Adrenaline is an α and β agonist.
- Activation of cardiac β receptors leads to cardiac excitation.
- High doses or rapid injection of adrenaline can induce cardiac arrhythmia.
- Propranolol is a cardiac β receptor antagonist.
- Atropine is an M receptor antagonist in the heart. It relieves the inhibitory effect of the vagus nerve on the heart.
Drug Administration Procedure
- Administer 0.3 ml/kg of 0.02% adrenaline rapidly. Record ECG 5 minutes later.
- Once ECG returns to normal, administer 0.5 ml/kg of 0.2% propranolol slowly. Record ECG 5 minutes after propranolol.
- Repeat step one (adrenaline) and record ECG 5 minutes later.
- Administer 1.6 ml/kg of 0.1% atropine. Record ECG 1-2 minutes later.
- Repeat step two (propranolol) and record ECG 3 minutes after propranolol.
- Repeat step one (adrenaline) and record ECG 5 minutes after.
Cautions and Considerations
- Administer adrenaline rapidly.
- Administer propranolol slowly.
- Analyze the difference in effects on blood pressure and heart induced by adrenaline, propranolol, and atropine.
- Determine if administering adrenaline three times has a different effect.
Results Summary
| Treatment Stage | Heart Rate | Rhythm |
|---|---|---|
| 1st Adrenaline | Slow-fast | Obvious arrhythmia |
| Propranolol after 1st Adrenaline | Slow | Normal |
| 2nd Adrenaline | Slow | Rare abnormalities |
| Atropine | Faster | Normal |
| 2nd Propranolol after 2nd Adrenaline | Slow | Normal |
| 3rd Adrenaline | N/A | No changes |
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