Noninvasive monitoring of end-tidal CO2 via nasal cannulas in spontaneously breathing children during the perioperative period.
OBJECTIVE
To determine the correlation between end-tidal CO2 and PaCO2 values measured via nasal cannulas in spontaneously breathing children during the perioperative period.


METHODS
Prospective evaluation.


METHODS
Pediatric intensive/intermediate care unit in a tertiary care referral center.


METHODS
Thirty postoperative surgical and trauma patients aged < or = 18 yrs (average age 7.8 yrs [range 6 months to 16 yrs] and average weight 28.3 kg (range 8.5 to 69).


RESULTS
Spontaneously breathing, nonintubated patients with an arterial cannula in place were selected for study. End-tidal CO2 was sampled from nasal cannulas by a sidestream aspirator and was estimated by infrared spectroscopy. The difference between PaCO2 and end-tidal CO2 was compared using linear regression analysis. A total of 55 blood gas measurements were obtained on the 30 patients. The PaCO2 to end-tidal CO2 gradient was < or = 4 torr in 54 of the 55 samples. The mean PaCO2 was 39.5 +/- 3.3 torr (5.27 +/- 0.44 kPa) with a mean end-tidal CO2 value of 39.7 +/- 3.8 torr (5.29 +/- 0.51 kPa). Linear regression analysis of arterial vs. end-tidal CO2 yielded a slope of 0.992 and p = .0001.


CONCLUSIONS
End-tidal CO2 measurement by infrared spectroscopy provided an accurate estimation of PaCO2 in this patient population. Its use may limit the need for invasive monitoring and/or repeated arterial blood gas analysis.
Department of Anesthesiology, Vanderbilt University, Nashville, TN 37232.
J D
JD
Tobias
J F
JF
Flanagan
T J
TJ
Wheeler
J S
JS
Garrett
C
C
Burney
D000293:Adolescent; D002245:Carbon Dioxide / Q000502:physiology*; D002404:Catheterization / Q000295:instrumentation; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D016014:Linear Models; D016343:Monitoring, Intraoperative / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data; D009666:Nose; D010313:Partial Pressure; D011446:Prospective Studies; D012119:Respiration / Q000502:physiology*; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation / Q000706:statistics & numerical data; D013990:Tidal Volume / Q000502:physiology
D002245:Carbon Dioxide