15. Respiratory Support for Asthma Exacerbation

Oxygen Support

• Nasal Cannula
  • Low flow setup
  • Flow range: 1/32L to 4L
  • Oxygen wall sources are available for use throughout the hospital
  • Fraction of inhaled oxygen (FiO2) is variable depending on the size of the child, respiratory rate, and amount of room air entrained.
  • General rule: FiO2 increases 3-4% per liter of flow (ex: 1L NC = FiO2 24%)
• OxyMask
  • Low flow device
  • Flow range 1-15L/min
  • FiO2 range 24-90%
    • True FiO2 is variable depending on the respiratory rate, minute ventilation, and the amount of air being entrained.
  • Consider for patients who are mouth breathing and do not tolerate nasal cannula or require 5L/min or more
  • Notify attending MD of patient’s oxygen requirement according to the limits referenced in the PEWS respiratory tool and/or when not able to maintain sat target goals on higher liter flows.
• Partial Non-Rebreather Mask
  • Deliver FiO2 up to ~70%
  • Low flow device with high FiO2 delivery
  • Flow range: 10-15L and reservoir bag must remain inflated
  • RTs must let attending MD know if FiO2 demands meet or exceed 50%

High Flow Nasal Cannula (HFNC)

• Considered a high flow device when flows are >10L
• Flow ranges: Up to 60L and FiO2 can be titrated from 21-100%
• Max FiO2 = 40%
• Aerosols provided through HFNC should be delivered at 0.25L/kg/min or less to ensure proper deposition
  • Max flow for asthmatic on HFNC receiving aerosol neb on med/surg = 0.25L/kg/min up to 10L and 40% FiO2

Non-Invasive Ventilation

• Administered in PICU setting only
• Positive pressure ventilation provided through a facemask or nasal mask set up
• Continuous Positive Airway Pressure (CPAP)
• Bilevel Positive Airway Pressure (BiPAP)
• Oxygen may be bled into the system for delivery

Intubation and Mechanical Ventilation

Covered in the PICU section of this reference guide.

Albuterol Therapy

• Can be provided via metered-dose inhaler (MDI) or nebulizer
• Albuterol is titrated via Bronchodilator Weaning Protocol
• Continuous Albuterol Dosing:
  • <20kg = 10mg/hour
  • >20kg = 15mg/hour
  • 20mg/hr reserved for PICU only
• A Situation Awareness Huddle should be initiated after 4 hours of continuous albuterol on the med/surg floors
  • A patient may continue receiving continuous albuterol past 4 hours as long as objective improvement can be documented. Improvement is defined as at least two of the following:
    • Decreased respiratory rate (RR)
    • Decreased oxygen requirement
    • Decreased Respiratory Care Score
    • Decreased Pediatric Early Warning Score (PEWS)
  • Total delivery time should be considered cumulative from ED to floor
  • Providing a therapeutic break from continuous does not restart the 4 hour limit
• Respiratory Therapists will assess patients every 30 minutes for the first hour and every hour subsequently. Communication must be open between physician and RT throughout.
• Consideration for need to increase to higher level of care should be considered if there is concern for impending or actual respiratory arrest. The progression from respiratory distress to respiratory failure to respiratory arrest can vary by patient. Respiratory failure can progress rapidly and be difficult to reverse. Therefore, it is important to emphasize the signs of impending respiratory arrest (e.g. altered level of consciousness, hypercapnia, silent chest or absence of wheezing, worsening hypoxemia). 
  
  

Reference: https://www.nhlbi.nih.gov/sites/default/files/media/docs/EPR-3_Asthma_Full_Report_2007.pdf