What is the protocol for isoprenaline (isoproterenol) infusion?

From the Guidelines

Isoprenaline (isoproterenol) infusion should be prepared at a concentration of 1-2 mg in 500 mL of 5% dextrose or normal saline (2-4 mcg/mL) and started at 0.5-1 mcg/minute, titrating gradually to effect, typically up to 5 mcg/minute, though doses up to 10 mcg/minute may be used in critical situations, as recommended by the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.

Key Considerations for Isoprenaline Infusion

• The infusion rate should be adjusted based on heart rate response, with a target heart rate typically between 60-100 beats per minute, depending on the clinical indication.
• Continuous monitoring of heart rate, blood pressure, ECG, and symptoms is crucial during administration.
• Isoprenaline is a non-selective beta-adrenergic agonist used for temporary management of symptomatic bradycardia unresponsive to atropine, as a bridge to pacemaker placement, and in certain cases of heart block, torsades de pointes, or refractory bronchospasm.
• Side effects include tachycardia, arrhythmias, hypotension, tremor, headache, and myocardial ischemia, necessitating caution in patients with coronary artery disease, tachyarrhythmias, or hypertension.
• Emergency resuscitation equipment should be immediately available, and the infusion should be reduced or discontinued if significant adverse effects occur.

Clinical Context and Evidence

The 2018 ACC/AHA/HRS guideline provides recommendations for the acute medical management of bradycardia attributable to sinoatrial node dysfunction (SND) or atrioventricular block, including the use of isoproterenol 1. The guideline emphasizes the importance of individualizing treatment based on the underlying cause of bradycardia, the presence of symptoms, and the patient's clinical context. Isoproterenol's nonselective beta-adrenergic agonist properties make it useful for enhancing sinus and atrioventricular nodal function without exerting a significant vasopressor effect, although its use requires careful monitoring due to potential side effects 1.

From the FDA Drug Label

DOSAGE AND ADMINISTRATION Initiate Isoproterenol Hydrochloride Injection at the lowest recommended dose and increase gradually based on patient response (2.2) Recommended initial dosage: Shock: 0.5 mcg to 5 mcg per minute as an intravenous infusion (2.2) DOSAGE AND ADMINISTRATION Initiate Isoproterenol Hydrochloride Injection at the lowest recommended dose and increase gradually based on patient response (2.2) Recommended initial dosage: Shock: 0.5 mcg to 5 mcg per minute as an intravenous infusion (2.2)

The protocol for isoprenaline (isoproterenol) infusion is to:

• Initiate at the lowest recommended dose
• Increase gradually based on patient response
• Recommended initial dosage for shock: 0.5 mcg to 5 mcg per minute as an intravenous infusion 2 2

From the Research

Isoprenaline Infusion Protocol

The protocol for isoprenaline (isoproterenol) infusion is not explicitly stated in the provided studies. However, the following information can be gathered:

• Isoprenaline is used to increase the heart rate and is administered as a continuous infusion 3.
• The dose of isoprenaline can vary, with one study using increasing doses of 1.7 micrograms/min and 3.4 micrograms/min each given for 30 min 3.
• Another study used a dose of 2-4 microg/min to facilitate the induction of supraventricular and ventricular tachycardias during electrophysiological study 4.
• The infusion of isoprenaline can cause paradoxical bradycardia in some patients, which can be a sign of hypervagotonia or organic conduction disturbance 4.

Key Considerations

When administering isoprenaline infusion, the following should be considered:

• The patient's heart rate and rhythm should be closely monitored 4, 3.
• The dose of isoprenaline should be adjusted according to the patient's response 3.
• The patient should be evaluated for any signs of adverse effects, such as paradoxical bradycardia or cardiac arrest 4, 5.
• The use of isoprenaline should be guided by clinical guidelines and the patient's individual needs 6, 7.