Treatment of Croup with Racemic Epinephrine
For moderate to severe croup, nebulized racemic epinephrine at a dose of 0.05 mL/kg of 2.25% solution (maximum 0.5 mL) in 2 mL of normal saline is recommended, with hospital admission considered only after three doses are required. 1, 2
Dosing and Administration
- Standard dosing is 0.05 mL/kg of 2.25% racemic epinephrine (maximum 0.5 mL) in 2 mL normal saline administered by nebulizer 2
- Many institutions use a standardized 0.5 mL dose for all patients regardless of weight 2
- If racemic epinephrine is unavailable, L-epinephrine (1:1000) can be substituted at a dose of 0.5 mL/kg up to 5 mL 2, 3
- Low-dose L-epinephrine (0.1 mg/kg) has been shown to be non-inferior to conventional dosing (0.5 mg/kg) with potentially fewer side effects 4
Treatment Algorithm Based on Severity
- For mild croup: oral corticosteroids only, no nebulized treatments needed 1
- For moderate to severe croup with stridor at rest or respiratory distress: nebulized racemic epinephrine plus oral corticosteroids 1, 5
- All patients with croup requiring racemic epinephrine should receive at least a single dose of dexamethasone (0.6 mg/kg) 6, 7
Monitoring and Observation
- Patients must be observed for at least 2-3 hours after the last dose of racemic epinephrine to monitor for symptom rebound 1, 2
- The effect of racemic epinephrine is short-lived, lasting approximately 1-2 hours 8, 1
- Clinical improvement is typically seen within 10-30 minutes after administration 9
Admission Criteria
- Recent guidelines recommend considering hospital admission only after 3 doses of racemic epinephrine are required, rather than the traditional 2 doses 8, 2
- This "3 is the new 2" approach has been shown to reduce hospital admissions by 37-57% without increasing adverse outcomes or revisits 8, 2
- In one study, the admission rate among patients who received 2 or fewer racemic epinephrine doses was reduced by over 50% using this approach 8
Discharge Criteria
- Patients can be safely discharged if they have:
- No stridor at rest
- Minimal or no respiratory distress
- Adequate oral intake
- Parents able to recognize worsening symptoms 1
- Patients treated with racemic epinephrine, oral dexamethasone, and mist who show sustained response after 3 hours of observation can be safely discharged home 7
Important Cautions
- Nebulized racemic epinephrine should not be used in children who are shortly to be discharged or on an outpatient basis due to risk of rebound symptoms 8, 5
- Racemic epinephrine should never be used in the home setting due to its short duration of action and potential adverse effects 2
- Potential adverse effects include increased heart rate, myocardial irritability, and increased oxygen demand 2
Common Pitfalls to Avoid
- Discharging patients too early after nebulized epinephrine (before the 2-hour observation period) 1
- Failing to administer corticosteroids in conjunction with racemic epinephrine 1, 6
- Relying on radiographic studies for diagnosis rather than clinical assessment 5
- Using only 1-2 doses of racemic epinephrine as the threshold for hospital admission, which may lead to unnecessary hospitalizations 8