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Strength of the Breuer-Hering inflation reflex in term and preterm infants
J P De Winter1, I T Merth, A Berkenbosch
1Department of Pediatrics, Leiden University, Netherlands.
Insights
The Breuer-Hering inflation reflex (BHIR) weakens with age. Respiratory distress syndrome (RDS) increases BHIR strength due to altered respiratory mechanics in infants.
Area of Science:
- Neonatal physiology
- Respiratory control mechanisms
Background:
- The Breuer-Hering inflation reflex (BHIR) plays a role in regulating breathing patterns.
- Factors like gestational age and respiratory conditions may influence BHIR strength in infants.
Purpose of the Study:
- To investigate the impact of respiratory distress syndrome (RDS), respiratory system mechanics, and gestational age on the BHIR in infants.
- To characterize the developmental trajectory of BHIR strength in preterm and term infants.
Main Methods:
- Studied three infant groups: ventilated preterm infants (with/without RDS), preterm infants over the first year, and healthy term infants.
- Assessed BHIR strength using end-inspiratory occlusions and measuring expiratory time ratios.
- Measured respiratory system static compliance via the multiple-occlusion technique.
Main Results:
- BHIR strength decreased with increasing gestational age in ventilated preterm infants.
- RDS and low respiratory compliance attenuated the decline in BHIR strength.
- BHIR strength was similar in preterm and term infants at term-equivalent age.
- BHIR strength diminished during the first year post-preterm birth.
Conclusions:
- BHIR strength decreases with advancing gestational and postnatal age.
- RDS increases BHIR strength by altering respiratory system mechanics.
Abstract:
The effect of the presence of the respiratory distress syndrome (RDS) or related factors (static compliance of the respiratory system and transcutaneous blood gases) and gestational age on the strength of the Breuer-Hering inflation reflex (BHIR) was studied in three groups of infants. Twenty-six ventilated preterm infants with and without RDS were studied 6 h after birth (group 1). In 24 preterm infants, we followed the development of reflex strength during the first year of life (group 2). Twenty-one healthy nonintubated term infants were studied within the first week of life (group 3). The BHIR was initiated by end-inspiratory occlusions, and the strength was characterized by the ratio of expiratory time after and without preceding airway occlusion. The static compliance of the respiratory system in ventilated infants was assessed by the multiple-occlusion technique. In group 1, reflex strength declined with increasing gestational age; in the presence of RDS or low respiratory compliance, the decline was less. Transcutaneous blood gases did not affect reflex strength. At term age, reflex strength was similar in spontaneously breathing preterm (group 2) and term infants (group 3). The BHIR decreased in strength during the first year after preterm birth. We conclude that 1) the strength of the BHIR decreases with increasing gestational and postnatal ages and 2) RDS, due to changes in respiratory system mechanics, causes an increase in reflex strength.