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Transcutaneous oxygen and carbon dioxide during the first half year of life in premature and normal term infants
T Hoppenbrouwers1, J E Hodgman, K Arakawa
1Department of Pediatrics, University of Southern California School of Medicine, Los Angeles.
Insights
Infant transcutaneous blood gas levels (PtCO2 and PtcCO2) change significantly during the first 6 months. Ventilatory regulation matures, impacting sleep state modulation and sudden infant death syndrome risk.
Area of Science:
- Neonatal physiology
- Respiratory control in infants
- Sleep studies
Background:
- Infant respiratory regulation undergoes significant development post-birth.
- Understanding gas exchange variability during sleep is crucial for assessing infant health.
- The period between 1 and 3 months is a critical window for sudden infant death syndrome (SIDS) risk.
Purpose of the Study:
- To investigate changes in transcutaneous oxygen (PtCO2) and carbon dioxide (PtcCO2) levels and variability during different sleep states in infants.
- To compare gas exchange parameters between healthy preterm and term infants.
- To assess the maturation of ventilatory regulation during early infancy.
Main Methods:
- Polysomnography with continuous transcutaneous PO2 and PCO2 monitoring in 33 infants (19 preterm, 14 term).
- Recordings conducted from 40 weeks postconceptional age up to 6 months.
- Computer analysis of polygraphic data to determine gas levels and variability during awake, active sleep, and quiet sleep states.
Main Results:
- No significant differences in PtCO2 or PtcCO2 between preterm and term infants at corrected ages.
- PtCO2 levels increased, while PtcCO2 levels decreased between 40 weeks and 3 months.
- Sleep states modulated PtcCO2 levels and variability, and PtCO2 variability, but not PtCO2 levels.
- Transient declines in PtCO2 and hypercapnic PtcCO2 values decreased with age, though hypercapnia prevalence warrants reevaluation of criteria.
Conclusions:
- Ventilatory control shows continuous adaptation between 1 and 3 months of age.
- Sleep state influences gas exchange regulation in infants.
- Findings suggest a need to refine hypercapnia criteria for transcutaneous measurements in young infants.
Abstract:
Repetitive polysomnograms were recorded from a total of 33 infants, 19 healthy preterm infants, and 14 term controls between 40 wk postconceptional age and 6 mo of age. These nighttime recordings lasted 2-4 h, except at 52 wk in preterm infants and at 3 mo of age in term infants when an overnight 12-h recording was performed. Minute by minute values of transcutaneous PO2 (PtCO2) and transcutaneous PCO2 (PtcCO2) levels and variability during the awake state, active sleep, and quiet sleep were obtained through computer analyses of the polygraphic data. The results from preterm infants at corrected postconceptional age could not be differentiated from those of control infants. PtCO2 levels rose between 40 wk and 3 mo, and PtcCO2 levels declined. Sleep states modulated only the variability of PtcO2, not the level; in contrast, state modulation was seen in both variability and level of PtcCO2 throughout the age span studied. During sleep the number of transient declines in PtCO2 greater than 2.03 kPa (15 mm Hg) decreased with advancing age. Hypercapnic PtcCO2 values decreased with age as well, but their prevalence in healthy, young infants suggests the need for reevaluation of criteria for hypercapnia based on transcutaneous measurements. The data demonstrate that ventilatory regulation continues to undergo changes between 1 and 3 mo, the age of highest risk for sudden infant death syndrome.