Dobutamine Dosing for a 9-Year-Old Child Weighing 15 kg
Start dobutamine at 2–3 mcg/kg/min (30–45 mcg/min for this 15 kg child) without a loading dose, then titrate upward every 15 minutes by doubling the infusion rate based on clinical response, with a therapeutic range of 2–20 mcg/kg/min. 1, 2
Initial Dosing Strategy
- Begin at 2–3 mcg/kg/min (30–45 mcg/min absolute dose for a 15 kg patient), which translates to an infusion rate that can be calculated using the "Rule of 6" method or standard concentration tables 1, 2
- No loading dose is required for pediatric patients with myocardial dysfunction 2
- The FDA label permits starting as low as 0.5–1.0 mcg/kg/min in highly unstable patients, but guideline-based practice favors the 2–3 mcg/kg/min starting point 3, 2
Titration Protocol
- Double the dose every 15 minutes (e.g., 2.5 → 5 → 10 mcg/kg/min) based on clinical response 2
- Monitor for:
Therapeutic Range and Maximum Dose
- Standard therapeutic range: 2–20 mcg/kg/min (30–300 mcg/min for this 15 kg child), with most patients responding within this range 1, 2, 3
- Doses >20 mcg/kg/min are rarely required and carry higher risk of tachycardia and arrhythmias 2
- The FDA label notes that on rare occasions, infusion rates up to 40 mcg/kg/min have been used to obtain the desired effect, though this is exceptional 3
Practical Infusion Calculation
Using the "Rule of 6" method for pediatric dosing 2:
- 0.6 × body weight (kg) = milligrams diluted to total 100 mL of saline
- For this 15 kg child: 0.6 × 15 = 9 mg in 100 mL
- Then 1 mL/h delivers 0.1 mcg/kg/min
- To achieve 2.5 mcg/kg/min starting dose: 25 mL/h
- To achieve 5 mcg/kg/min: 50 mL/h
- To achieve 10 mcg/kg/min: 100 mL/h
Alternatively, using standard concentrations from the FDA label 3:
- For a 1,000 mcg/mL concentration and 15 kg patient at 2.5 mcg/kg/min: 2.25 mL/h
- At 5 mcg/kg/min: 4.5 mL/h
- At 10 mcg/kg/min: 9 mL/h
Critical Monitoring Requirements
- Continuous ECG telemetry is mandatory because dobutamine increases the risk of both atrial and ventricular arrhythmias, particularly at higher doses 1, 2
- Blood pressure monitoring (invasively or non-invasively) is required during administration 2
- Halt dose escalation if excessive tachycardia, new arrhythmias, or signs of myocardial ischemia develop 2
Pediatric-Specific Considerations
- Infants <12 months may be less responsive to dobutamine and may require higher doses or alternative agents, though this 9-year-old child should respond normally 2
- Pediatric patients demonstrate wide variability in hemodynamic responses and clearance kinetics, with mean plasma clearance of 82–151 mL/min/kg 4, 5
- In one pediatric study, cardiac index increased by >10% in four of seven patients at doses as low as 0.5 mcg/kg/min, but the standard starting dose remains 2–3 mcg/kg/min 4
- Dobutamine acts principally by stimulating β1-receptors, producing both inotropic and chronotropic effects; the intrinsically higher heart rate of children means tachycardia can reach unacceptable levels in some cases 6
Common Pitfalls and Safety Precautions
- Have esmolol (0.5 mg/kg) readily available to rapidly reverse excessive tachycardia or other adverse dobutamine effects 2
- Do not mix dobutamine with 5% Sodium Bicarbonate Injection or any other strongly alkaline solution due to physical incompatibility 3
- Do not use with agents containing both sodium bisulfite and ethanol 3
- In patients with atrial fibrillation, dobutamine may facilitate AV conduction and precipitate dangerous tachycardia; use extreme caution 2
- Diluted solutions should be used within 24 hours of preparation 3
When to Stop or Adjust
- Discontinue or reduce if worsening hypotension or arrhythmias occur 2
- Gradual tapering is recommended when discontinuing: decrease by steps of 2 mcg/kg/min every other day 2
- If the patient is on chronic beta-blockers, doses up to 20 mcg/kg/min may be required to overcome receptor blockade, though this is less common in pediatric patients 2