High Carboxyhaemoglobin Levels in Preterm Infant Linked to Bronchopulmonary dysplasia and IVH

A potential marker of oxidative stress in the neonatal population is carboxyhaemoglobin (COHb). Despite being readily available with potential clinical utility, COHb levels are currently not routinely considered in the clinical assessment and monitoring of disease progression in prematurely born infants. Also, studies assessing the relationship of COHb to BPD and other free-radical-related diseases are limited. Therefore, Dr Theodore Dassios and his team conducted a study to assess the relationship of COHb levels in the first seven days of birth to the development of BPD and other free-radical-related diseases.

In a retrospective analysis, the researchers included 104 infants born at less than 30 weeks of gestation and routinely performed COHb via blood gas samples. The major outcome assessed was maximum COHb per infant per day recorded for the first 28 days and BPD and other free-radical-related diseases including intraventricular haemorrhage (IVH). They also recorded the severity of BPD, requirement for home oxygen on discharge and survival to discharge.

Key findings of the study:

• Upon analysis, the researchers found that infants who developed BPD (n = 76) had significantly higher COHb levels in the first seven days [1.7% ] compared to those that did not develop BPD [1.6%].
• They also found higher COHb levels in the first seven days after birth in infants with grade three/four IVH [n = 20; 1.9%] compared to those without [1.6%].
• However, they noted that the COHb levels were not associated with the duration of ventilation, BPD severity or survival to discharge.

The authors concluded, "Raised COHb levels may act as an early warning sign, allowing clinicians to differentiate prematurely born infants at greater the risk of developing a free-radical-related disease, in particular BPD and IVH. This may allow identification of prematurely born infants who could benefit from novel antioxidant therapies to potentially mitigate the harmful consequences of oxidative stress."

They further added, " As an existing resource, COHb levels could also offer a cost-effective method of enhancing routine care provided to prematurely born infants admitted to the neonatal unit."

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DOI: https://doi.org/10.1016/j.earlhumdev.2021.105523