Respiratory Failure

Respiratory failure is the inability to provide O2 and/or remove CO2 at a rate that meets metabolic demands. Respiratory failure can evolve from diseases affecting the lungs (e.g., pneumonia, bronchiolitis), airway (e.g., croup), respiratory muscle strength (e.g., Guillain-Barre, Duchenne’s muscular dystrophy), chest wall (e.g., flail chest), or control of breathing (e.g., apnea of infancy, encephalopathy). Not all patients with respiratory failure require intubation and mechanical ventilation.

Acute hypoxemic respiratory failure is characterized by a PaO2 < 60mmHg or SpO2 < 90% with a normal or low PaCO2. Acute hypercapnic respiratory failure is characterized by a PaCO2 > 50mmHg.

Children with a need for any of the following interventions likely meet the criteria for acute respiratory failure:

Neonatal Period:

• ≥ 2L supplemental O2 via nasal cannula (as this provides CPAP)

• Any baby on CPAP, BiPAP, or mechanical ventilation.

Beyond the Neonatal Period:

• ≥ 4L per minute O2 by nasal cannula and/or ≥ 30% FiO2 (this level of support likely correlates to a PaO2:FiO2 ratio < 300 in children with normal hemoglobin).

• Any child on CPAP, BiPAP, or mechanical ventilation.

• Need for continuous albuterol (>2 hours)

Chronic Respiratory Failure (CRF) is usually a combination of chronic hypoxemia, hypercapnia, and compensatory metabolic alkalosis (elevated bicarbonate levels) of at least 28 days or longer. Patients with CRF usually require home supplemental O2 or ventilator support or have a baseline SaO2 < 88% on room air or PaCO2 > 50 mmHg with a normal pH.

Acute on Chronic Respiratory Failure describes patients with chronic respiratory failure along with worsening in their baseline respiratory symptoms or ANY increase in baseline O2 needs.