From the Guidelines
High FiO2 should be avoided in infants with atrial septal defect (ASD) as it can exacerbate left-to-right shunting, leading to increased pulmonary blood flow and potential heart failure. The administration of high oxygen concentrations can decrease pulmonary vascular resistance while systemic vascular resistance remains unchanged or increases, creating a greater pressure gradient that forces more blood from the left atrium to the right atrium through the ASD [ 1 ]. This can result in pulmonary overcirculation, edema, and volume overload of the right heart, ultimately leading to heart failure. Furthermore, prolonged exposure to high oxygen concentrations can cause oxygen toxicity in the lungs, particularly in premature infants who are already at risk for conditions like bronchopulmonary dysplasia [ 1 ].
When supplemental oxygen is necessary for these infants, it should be carefully titrated to maintain adequate oxygenation, typically targeting an SpO2 of 90-95%, without providing excessive oxygen that could exacerbate the left-to-right shunt [ 1 ]. It is essential to balance the need for adequate oxygenation with the risk of worsening the ASD's hemodynamic effects. The American Heart Association and American Thoracic Society guidelines emphasize the importance of careful management of infants with ASD and other congenital heart defects to prevent complications and improve outcomes [ 1 ].
Key considerations in the management of infants with ASD include:
- Careful titration of supplemental oxygen to maintain adequate oxygenation without exacerbating left-to-right shunting
- Monitoring for signs of pulmonary overcirculation and heart failure
- Avoiding excessive oxygen exposure to prevent oxygen toxicity
- Regular follow-up with serial echocardiograms to assess the defect's hemodynamic effects and guide management decisions [ 1 ].
By prioritizing these considerations and carefully managing oxygen therapy, clinicians can help minimize the risks associated with ASD and improve outcomes for affected infants.
From the Research
High FiO2 in Infants with ASD
- High FiO2 is avoided in infants with atrial septal defect (ASD) due to the risk of exacerbating pulmonary hypertension (PH) 2.
- Infants with ASD are at a higher risk of developing PH, and high FiO2 can increase pulmonary blood flow, promoting PH 2.
- Studies have shown that infants with ASD have a higher incidence of PH compared to those without ASD, and high FiO2 can worsen the condition 2.
Pulmonary Hypertension in ASD
- Pulmonary hypertension is a common complication in adults with untreated ASD, with a prevalence of 8-10% 3.
- The development of PH in infants with ASD is associated with lower gestational age, smaller birthweight, and more prematurity complications 2.
- Infants with ASD and PH have a higher risk of right ventricular dysfunction, dilation, and hypertrophy compared to those without PH 2.
Management of ASD with PH
- The management of ASD with PH depends on the severity of the condition and the presence of other congenital heart defects 4, 5.
- Transcatheter closure of ASD can be an effective treatment for infants with PH, but it requires careful evaluation of the patient's hemodynamic data and clinical picture 5, 3.
- Fenestrated device closure has been shown to be a safe and effective treatment for adults with ASD-associated PH and decompensated heart failure 6.