Endoscopic intratracheal carbon dioxide measurements during pediatric flexible bronchoscopy.
BACKGROUND
CO2 monitoring is recommended for thoracic telescopic procedures and for spontaneous breathing general anesthesia in children. During flexible bronchoscopy (FB) in children, the various currently available methods of CO2 measurements are limited. The CO2 falls and increases have been reported in FB but it is unknown whether airway lesions predispose to CO2 change. The aim of this study was to describe and validate endoscopic intratracheal CO2 measurements in children undergoing FB under spontaneously breathing GA.


METHODS
Endtidal CO2 (P(E)CO2) measurements at the start (Start-CO2) and end (End-CO2) of FB on 100 consecutive children were performed using a newly designed endoscopic intratracheal method. To validate the method blood gas sampling was simultaneously performed in 28 children and results analyzed using the Bland and Altman method, intraclass correlation and 95% range for repeatability.


RESULTS
End-CO2 and CO2-change (End-CO2 minus Start-CO2) were significantly different in children with airway lesions (CO2 change: no lesion = 3 mmHg, extrathoracic airway lesion = 4.5, intrathoracic airway lesion = 8, P = 0.038). There was no significant difference in Start-CO2 values among the groups. CO2-change in those aged < or =12 months was similar to those >12 months. Intratracheal CO2 measurements were comparable with arterial blood values in the Bland and Altman plots. The intraclass correlation was 0.69 and 95% range for repeatability was 3.7-4.17 mmHg.


CONCLUSIONS
Midtracheal P(E)CO2 provides a useful estimate of P(a)CO2 for monitoring the respiratory status of children undergoing FB. The presence of airway lesions rather than age is associated with significant increased PCO2 rise.
Department of Respiratory Medicine, Royal Children's Hospital, Herston, Queensland, Australia. annechang@ausdoctors.net
Anne B
AB
Chang
Gregory E
GE
Moloney
Peter J
PJ
Harms
I Brent
IB
Masters
D000293:Adolescent; D000768:Anesthesia, General / Q000379:methods; D001784:Blood Gas Analysis / Q000379:methods; D001999:Bronchoscopy / Q000379:methods*; D019296:Capnography / Q000295:instrumentation / Q000379:methods; D002245:Carbon Dioxide / Q000032:analysis*; D002648:Child; D002675:Child, Preschool; D004724:Endoscopy / Q000379:methods*; D005260:Female; D005336:Fiber Optic Technology / Q000379:methods; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D011446:Prospective Studies; D015203:Reproducibility of Results; D013990:Tidal Volume; D014132:Trachea / Q000502:physiology
D002245:Carbon Dioxide