A novel method of distal end-tidal CO2 capnography in intubated infants: comparison with arterial CO2 and with proximal mainstream end-tidal CO2.
OBJECTIVE
The objective of this study was to evaluate a novel method of distal end-tidal CO2 capnography by comparison with PaCO2 and with the more standard method that measures mainstream proximal end-tidal CO2 in intubated infants.


METHODS
Included in the study were all infants who were ventilated with conventional mechanical ventilation and intubated with a double-lumen endotracheal tube in our NICU during the study period. Data were collected prospectively from 2 capnographs simultaneously and compared with PaCO2. Sidestream distal end-tidal CO2 was measured by a Microstream capnograph via the extra port of a double-lumen endotracheal tube. Mainstream proximal end-tidal CO2 was measured via capnograph connected to the endotracheal tube.


RESULTS
Twenty-seven infants (median [range] birth-weight: 1835 [490-4790] g; gestational age: 32.5 [24.8-40.8] weeks) participated in the study. We used for analysis 222 and 212 measurements of distal end-tidal CO2 and proximal end-tidal CO2, respectively. Distal compared with proximal end-tidal CO2 had a better correlation with PaCO2 and a better agreement with PaCO2. The accuracy of distal end-tidal CO2 decreased, but it remained a useful measure of PaCO2 in the high range of PaCO2 (>or=60 mmHg) or in conditions of severe lung disease. A subanalysis for infants who weighed<1500 g (13 infants, 84 observations) revealed a good correlation and agreement between distal end-tidal CO2 and PaCO2 and poor correlation and agreement for proximal end-tidal CO2.


CONCLUSIONS
Distal end-tidal CO2 measured via a double-lumen endotracheal tube was found to have good correlation and agreement with PaCO2, remained reliable in conditions of severe lung disease, and was more accurate than the standard mainstream proximal end-tidal CO2.
Kugelman
Amir
A
Pediatric Pulmonary Unit, Department of Neonatology, Bnai-Zion Medical Center, Bruce Rappaport Faculty of Medicine, 47 Golomb St, Haifa, 31048, Israel. dramir@netvision.net.il
Zeiger-Aginsky
Dana
D
Bader
David
D
Shoris
Irit
I
Riskin
Arieh
A
D001784:Blood Gas Analysis; D001785:Blood Gas Monitoring, Transcutaneous / Q000379:methods; D019296:Capnography / Q000379:methods*; D002245:Carbon Dioxide / Q000097:blood*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D007442:Intubation, Intratracheal; D007557:Israel; D016014:Linear Models; D008297:Male; D011336:Probability; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D012121:Respiration, Artificial / Q000379:methods; D012127:Respiratory Distress Syndrome, Newborn / Q000175:diagnosis* / Q000628:therapy*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013990:Tidal Volume
D002245:Carbon Dioxide