Breathing and Swallowing: The Next Frontier

Abstract

The anatomical overlap of the pathways for air passage and nutrition necessitate precise coordination between the two vital functions. Neuroanatomic structures in the brainstem for sucking, breathing, and swallowing are also in close proximity and must swiftly coordinate the processes. In a healthy neonate, the oropharyngeal experience and stimulation of early feeding enables respiratory control during suckling to develop. Despite wide variability among the methods used to investigate breathing and swallowing coordination in infancy, a consistent finding of postswallow exhalation has been reported. Postswallow exhalation is significant because the positive airflow of exhalation is believed to provide airway clearance. Preterm neonates and infants swallow during all phases of the respiratory cycle, but ultimately progress to the most commonly reported pattern, which is inhale-swallow-exhale. This pattern is similar to the adult pattern of exhale-swallow-exhale. Monitoring respiratory signals during nonnutritive sucking and early feeding may help to identify newborns with increased risk of aspiration and assist with clinical decision making.

Vertebrate Evolution Conserves Hindbrain Circuits despite Diverse Feeding and Breathing Modes

“…Therefore, bringing fluid into the mouth to be swallowed is likely the fundamental process common to all developing vertebrates. For example, it is known that fetal swallowing of amniotic fluid emerges right after major organogenesis around 10–14 weeks of gestation in human and is observed in early development of chicks, sheep, rodents, and monkeys ( Ross and Nijland, 1998 ; Delaney and Arvedson, 2008 ; Mashayekhi et al, 2011 ; Gross and Trapani-Hanasewych, 2017 ; Maynard et al, 2020 ). This process of transporting fluid into the body is repeatedly executed and requires coordinated activation of oropharyngeal muscles ( Sherman et al, 1990 ).…”