Dose of Adrenaline and dopamine in bradycardia
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bradycardia management epinephrine dopamine
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I now have comprehensive data from multiple authoritative emergency medicine and anesthesia textbooks. Here is the complete answer:
Adrenaline (Epinephrine) and Dopamine in Bradycardia
Both drugs are second-line agents used when atropine fails or is contraindicated. They are given as IV infusions, not bolus doses (except in cardiac arrest).
Step-by-step Management Context
- First line: Atropine - 1 mg IV every 3-5 min, max total dose 3 mg
- If atropine fails or is inappropriate (e.g., heart transplant, Mobitz II / third-degree AV block with wide QRS): start epinephrine or dopamine infusion, and prepare for transcutaneous pacing (TCP)
- Atropine is unlikely to work in infranodal blocks (Mobitz II, complete heart block) - go straight to TCP + chronotropes
Adrenaline (Epinephrine) - IV Infusion for Bradycardia
| Parameter | Detail |
|---|---|
| Indication | Symptomatic bradycardia unresponsive to atropine; cardiogenic shock with bradycardia |
| Preparation | 1 mg in 500 mL normal saline (concentration: 2 mcg/mL) |
| Starting dose | 2 mcg/min IV infusion |
| Titration | Escalate as needed at 3-5 minute intervals |
| Range | 2-10 mcg/min |
| Mechanism | Alpha + Beta adrenergic effects: increases HR, BP, CO |
"For IV infusion in patients with cardiogenic shock or symptomatic bradycardia, the dose is 1 milligram in 500 mL of normal saline beginning at 2 to 10 micrograms/min and escalating as needed at 3- to 5-minute intervals." - Tintinalli's Emergency Medicine
Pediatric dose (cardiac arrest / symptomatic bradycardia): 0.01 mg/kg IV/IO of 1:10,000 solution (0.1 mL/kg), max single dose 1 mg, repeat every 3-5 min PRN.
Dopamine - IV Infusion for Bradycardia
| Parameter | Detail |
|---|---|
| Indication | Symptomatic bradycardia, especially if hypotension co-exists |
| Starting dose | 2-5 mcg/kg/min IV |
| Usual range | 2-20 mcg/kg/min, titrated by 5-10 mcg/kg/min increments |
| Maximum dose | Up to 50 mcg/kg/min (some sources 20-50 mcg/kg/min) |
| Mechanism (dose-dependent): | |
| - Low dose (2-5 mcg/kg/min) | Dopaminergic + mild beta-1: increases HR and inotropy |
| - Medium dose (5-10 mcg/kg/min) | Beta-1 dominant: increases HR, BP, CO |
| - High dose (>10-15 mcg/kg/min) | Alpha dominant: vasoconstriction, decreases renal perfusion |
"Dopamine is a catecholamine with both alpha- and beta-adrenergic actions and can be titrated to target heart rate or vasoconstriction more selectively. At lower doses, dopamine has a more selective effect on inotropy and heart rate; at higher doses (>10 mcg/kg/min), it also has vasoconstrictive effects." - Miller's Anesthesia
Quick Comparison
| Feature | Epinephrine | Dopamine |
|---|---|---|
| Dose form in bradycardia | 2-10 mcg/min infusion | 2-20 mcg/kg/min infusion |
| Weight-based dosing? | No (fixed mcg/min) | Yes (mcg/kg/min) |
| Preferred if hypotension present | Yes | Yes |
| Preferred if low risk of arrhythmia | Either | Dopamine preferred |
| Arrhythmia risk | Higher | Lower at low doses |
Key Points
- Both are bridge therapies until transcutaneous or transvenous pacing is established
- Neither works well in complete heart block with wide QRS - pacing is the definitive treatment
- In post-cardiac transplant patients, atropine is ineffective (denervated heart); use isoproterenol 2-10 mcg/min or pacing
- Do not add epinephrine to alkaline infusion solutions
Sources: Tintinalli's Emergency Medicine; Rosen's Emergency Medicine; Miller's Anesthesia, 10e; Harriet Lane Handbook, 23e
bradycardia algorithm according to ACLS
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ACLS bradycardia algorithm 2020 AHA steps
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Here is the complete ACLS Bradycardia Algorithm:
ACLS Adult Bradycardia Algorithm (2020 AHA Guidelines)
(Reprinted with permission - ACLS Advanced Cardiovascular Life Support Provider Manual. © 2020 American Heart Association)
Step-by-Step Breakdown
Step 1 - Initial Assessment
- Confirm heart rate < 50/min with bradyarrhythmia
- Check for a pulse - if no pulse, switch to Cardiac Arrest Algorithm
Step 2 - Identify and Treat Underlying Cause (Simultaneously)
- Maintain patent airway; assist breathing if needed
- Oxygen (if hypoxemic)
- Cardiac monitor to identify rhythm; monitor BP and SpO2
- Establish IV access
- 12-lead ECG if available - do NOT delay therapy
- Consider possible hypoxic and toxicologic causes
Common underlying causes:
- Myocardial ischemia / infarction
- Drugs (beta-blockers, calcium channel blockers, digoxin)
- Hypoxia
- Electrolyte abnormalities (e.g., hyperkalemia)
Step 3 - Key Decision: Is the Bradycardia Causing Symptoms?
Ask: Is there persistent bradyarrhythmia causing any of the following?
| Sign of Instability |
|---|
| Hypotension |
| Acutely altered mental status |
| Signs of shock |
| Ischemic chest discomfort |
| Acute heart failure |
- NO → Monitor and observe
- YES → Proceed to treatment
Step 4 - Symptomatic/Unstable: Give Atropine
Atropine - First-line drug
| Dose | |
|---|---|
| First dose | 1 mg IV bolus |
| Repeat | Every 3-5 minutes |
| Maximum total dose | 3 mg |
Key 2020 update: Dose increased from 0.5 mg to 1 mg per dose to improve efficacy and avoid paradoxical bradycardia (doses < 0.5 mg can cause paradoxical bradycardia).
Note: Atropine is NOT expected to work in:
- Mobitz type II second-degree AV block
- Third-degree (complete) AV block with wide QRS
- Post-cardiac transplant patients (denervated heart)
Step 5 - If Atropine is Ineffective: Three Options (can use simultaneously)
| Option | Drug / Intervention | Dose |
|---|---|---|
| A | Transcutaneous Pacing (TCP) | Rate typically 60-80/min; use sedation |
| B | Dopamine IV infusion | 5-20 mcg/kg/min - titrate; taper slowly |
| C | Epinephrine IV infusion | 2-10 mcg/min - titrate to response |
TCP and drug infusion can be used together (and/or).
Step 6 - Consider
- Expert consultation (cardiology)
- Transvenous pacing (definitive treatment for high-degree AV block)
Important Clinical Notes
| Scenario | Action |
|---|---|
| Mobitz II / complete heart block | Skip atropine - go directly to TCP + pacing preparation |
| Post-cardiac transplant | Atropine ineffective - use isoproterenol 2-10 mcg/min or pace |
| Suspected drug toxicity (BB, CCB) | Treat the cause (glucagon, calcium, lipid emulsion) |
| Reversible cause found | Treat the cause first |
Quick Dose Summary Box (from the Algorithm)
| Drug | Dose |
|---|---|
| Atropine | 1 mg IV bolus, repeat q3-5 min, max 3 mg |
| Dopamine | 5-20 mcg/kg/min IV infusion |
| Epinephrine | 2-10 mcg/min IV infusion |
Sources: Barash's Clinical Anesthesia 9e; Miller's Anesthesia 10e (Fig. 82.6 - 2020 AHA Adult Bradycardia Algorithm); AHA ACLS Guidelines 2020
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