Upper airway reflexes in newborns with respiratory distress syndrome.

In 16 newborns with respiratory distress syndrome (RDS) not artificially ventilated, oesophageal pressure was recorded with an electromanometer and the reactions to mechanical stimulation of the upper airways by means of a nylon fibre were investigated. The results were compared with the values obtained in 16 newborns without cardiorespiratory disturbances. The reactions were evoked by mechanical stimulation of the airways. Mechanical stimulation of the nasal mucosa produced expulsive reactions only in 45% of cases in newborns with RDS as compared with 95% in healthy newborns (p less than 0.001). Stimulation of the oropharyngeal and laryngeal regions elicited expulsive reactions in 48% of cases in newborns with RDS, but 74% in healthy newborns (p less than 0.001). In other cases, inhibition of breathing or apnoea was the most common reaction. The expulsive component of responses such as sneezing, expiratory reaction and crying was weaker in newborns with RDS than in control infants. The inspiratory component of sneezing and coughing, on the contrary, was stronger in newborns with RDS. These results indicate that active elimination of irritants from the airways is reduced in newborns with RDS.