CO and NO pulmonary diffusing capacity during pregnancy: Safety and diagnostic potential

Area of Science:

• Pulmonary Medicine
• Maternal-Fetal Medicine
• Neonatal Medicine

Background:

• Pulmonary diffusing capacity measurements using inhaled gases are crucial for assessing lung function.
• Safety data for carbon monoxide (CO) and nitric oxide (NO) inhalation during pregnancy and in neonates are essential.

Purpose of the Study:

• To review scientific evidence on the safety of CO and NO inhalation for pulmonary diffusion capacity (DLCO and DLNO) testing in pregnant women and neonates.
• To assess maternal, fetal, and neonatal outcomes associated with these testing methods.

Main Methods:

• Review of eight studies involving 650 pregnant women undergoing DLCO measurements.
• Analysis of studies administering NO to 11 pregnant women and 1105 neonates for therapeutic purposes.
• Evaluation of reported maternal, fetal, and neonatal outcomes.

Main Results:

• No adverse maternal, fetal, or neonatal outcomes were reported in studies using CO for DLCO measurements.
• NO therapy was effective for pregnant women with pulmonary hypertension.
• NO therapy improved oxygenation and survival in neonates with respiratory failure and pulmonary hypertension, with minor transient side effects.

Conclusions:

• Maternal carboxyhemoglobin levels can safely increase to 5% with CO inhalation limits (0.3% for
• NO inhalation up to 80ppm for
• The risk of fetal or neonatal death from diffusion testing is minimal and significantly lower than general mortality risks.