Airway Obstruction in Premature Newborns: A Missing Link: In Reply

In Reply .— Ng et al, in response to our article,1 raise some important points that we feel require additional clarifications. Their first concern regards the classification of apneas and therefore the type of apnea that olfactory treatment is effectively able to prevent. In our study, we focused on central apneas. Consistent with general acceptation,2,3 apneas were classified as central when “complete cessation of breathing movements” occurred. Indeed, during pure obstructive apnea, thoracic movements still persist, and such events were not further considered in our study. Ng et al are right to outline that some mixed events occur. In a great majority, these events are of central origin, followed by an obstructive component.4 They are effectively more difficult to distinguish from pure central apneas on the basis of thoracic movements, because part of such episodes occurs in the absence of any respiratory effort.4 In consequence, some events that we considered as central may have been in fact central-obstructive apnea. We agree on this point. Nevertheless, the risk of error should …