Article Text

  1. E Lopez1,2,3,
  2. S Grabar1,4,
  3. A Barbier1,2,3,
  4. B Krauss5,6,
  5. P H Jarreau1,2,3,
  6. G Moriette1,2,3
  1. 1Faculte de Medecine, Universite Paris Descartes, Paris, France
  2. 2AP-HP, Groupe Hospitalier Cochin-Saint Vincent de Paul, Service de Medecine Neonatale de Port-Royal, Paris, France
  3. 3PremUP, Paris, France
  4. 4AP-HP, Groupe Hospitalier Cochin–Saint Vincent de Paul, Service de Biostatistiques, Paris, France
  5. 5Division of Emergency Medicine, Children’s Hospital, Boston, Massachusetts, USA
  6. 6Harvard Medical School, Boston, Massachusetts, USA


Background Two non-invasive techniques are available for monitoring carbon dioxide (CO2) in neonatal intensive care unit (NICU) patients. Transcutaneous monitoring (TcCO2) is widely used, whereas the application of end-tidal CO2 (capnography) has been limited in newborn infants, due to accuracy problems.

Objectives To determine in preterm infants the accuracy of end-tidal CO2 (EtCO2) monitoring, and to assess the influence of alveolar plateau duration; to compare EtCO2 and TcCO2 for detecting low and high values of PCO2.

Materials and Methods In 38 preterm infants (birth weight <1500 g) undergoing mechanical ventilation, recordings of EtCO2 (capnography using sidestream device: Capnostream) were performed. Results were compared with those of CO2 venous (umbilical venous catheter) pressure measured from one blood sample (PvCO2), and with simultaneous TcCO2 recordings. In EtCO2/PvCO2 measurement pairs, the bias (EtCO2/PvCO2) and the intraclass correlation coefficient (ICC) were calculated. EtCO2 and TcCO2 techniques were compared for the detection of low (PvCO2 <45 mm Hg) and high PCO2 (PvCO2 >60 mm Hg), using receiver operator characteristic curves (area under the curve, AUC).

Results 104 EtCO2/PvCO2 pairs obtained from 38 patients were analysed. The bias was −1 ± 7.8 mm Hg. It decreased when the alveolar plateau increased. The ICC was 0.28. AUC for EtCO2, compared with TcCO2, were: 0.82 versus 0.89 for high PCO2 (p = 0.18) and 0.89 versus 0.90 for low PCO2 (p = 0.71), respectively.

Conclusion In ventilated preterm infants, the correlation between EtCO2 and PvCO2 was low. Capnography may, however, be useful in the monitoring of CO2 trends.

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