HRF Overview
Defining hypoxic respiratory failure (HRF)
HRF is a relative deficiency of oxygen in arterial blood, often associated with insufficient ventilation.1 This deficiency can be reflected by progressive respiratory and metabolic acidosis and remains a persistent challenge in the management of some newborns.2,3
Common underlying diseases of HRF*
Idiopathic PPHN
- No underlying lung disease4
Respiratory distress syndrome2,4†
- Acute lung injury
- Surfactant deficiency or inactivation
- Pulmonary edema, volume loss
Meconium aspiration syndrome4,5†
- Airway obstruction with gas trapping
- Surfactant inactivation
- Pneumonitis
Transient tachypnea of the newborn4†
- Streaky lungs with fluid in the minor fissure
- Mild hypoxemia
- Occasionally profound and/or prolonged hypoxemia
Pneumonia/sepsis2,4-6†
- Patchy infiltrates and/or ground glass appearance
- Hypoxemia and systemic hypotension
- Group B streptococcus or gram-negative organisms
Transient tachypnea was not one of the primary diagnoses of patients in the INOMAX pivotal trials.
*© Crown copyright [2000-2005] Aukland District Health Board.
†Images courtesy of John P. Kinsella, MD, and Steven H. Abman, MD.
HRF in Neonates: Pathophysiology2
Pathophysiology of HRF in neonates2:
- Intrapulmonary shunt: Pulmonary arterial blood reaches the pulmonary venous side without passing through ventilated areas of the lung
- Extrapulmonary shunt (PPHN): Right-to-left shunting of blood bypasses the lung through fetal channels (patent ductus arteriosus and/or foramen ovale)
- Ventilation/perfusion (V/Q) mismatch: Imbalance between ventilation and perfusion
Decreased V/Q
Normal V/Q
