Sidestream end-tidal capnometry as related to infant's position and maturation.

UNLABELLED: The objective of this study was to investigate the effect of body position on sidestream, end-tidal carbon dioxide (EtCO2) wave measurements in maturing infants. Sidestream EtCO2 wave patterns were analysed longitudinally in 20 preterm infants (born at > or = 32 wk) at 32-37 wk gestation, and in 39 full-term controls. Capnography measurements included maximal EtCO2, inspired CO2 and frequency of apnoea events (>3 s) in the supine, supine with inclination, side and prone positions. Apnoea frequency decreased during maturation, and was less prevalent in the prone than in the supine and side positions in preterm as well as in term infants (p < 0.05). No clinically significant apnoea episodes were found in our cohort. EtCO2 in term infants was lower than that in preterm infants (p < 0.05) and was not affected by sleep position in the most premature (<33 wk) and in term infants (>36 wk). EtCO2 was higher in the prone position than in supine or side positions in infants between 33 and 35 wk gestation (p < 0.01). CONCLUSION: Short apnoeic episodes decrease during maturation, and are less prevalent in the prone position in maturing infants (32-37 wk). Only modest changes in EtCO2 were recorded in the different positions during maturation.

Capnography in spontaneously breathing preterm and term infants.

OBJECTIVE: To investigate sidestream EtCO2 wave patterns as related to prematurity. DESIGN: The EtCO2 wave pattern was analyzed longitudinally in 20 sequential preterm, 32-37 weeks of gestation and 39 fullterm controls. Infants with a cardiorespiratory disease, neurological deficit or a metabolic disorder were not included in the study. Sidestream EtCO2 was employed. Wave patterns were identified and baseline expiratory/inspiratory length and wave amplitude were measured. RESULTS: Two predominant (about 75%) wave patterns were identified: (i) (with plateau) significantly more prevalent among infants born at term as compared with preterm infants across their postconceptional ages (PCA) (P=0.005-0.04), (ii) (plateau free) significantly more prevalent among the youngest preterm infants as compared with the fullterm controls. Expiratory length was significantly correlated with respiratory rate (RR) across ages (P=0.01-0.001) whereas inspiratory length was correlated with RR among the two youngest groups of infants only (P=0.002 and 0.004). Wave patterns were not found to be affected by environmental temperatures, blood pressure, body weight, haemoglobin level, aminophylline or O2 supplementation. CONCLUSION: These findings suggest that EtCO2 wave pattern distribution among preterm infants is distinctly different from that of term controls, regardless of PCA, while inspiration is related to the degree of maturity. Alveolar pathology could probably be missed by sidestream capnography.