The accuracy of non-invasive nasal capnography in morbidly obese patients after bariatric surgery.
OBJECTIVE
to assess the accuracy of nasal capnography for the monitoring of ventilation in extubated morbidly obese patients, following bariatric surgery.


METHODS
prospective descriptive study.


METHODS
Post-anesthesia care unit.


METHODS
25 consecutive morbidly obese patients admitted to the PACU after open bariatric surgery.


METHODS
Patients had a nasal cannula designed to administer oxygen (3 L/min) and to sample expired CO2 by a coaxial catheter.


METHODS
Capnographic waveform, end-tidal CO2 (ETCO2) and respiratory rate (RRd) were displayed by a capnometer (Datex-Ohmeda). Arterial CO2 pressure (PaCO2) was measured by blood gas analysis. Respiratory rate was measured by visual inspection of chest breathing motions (RRm). Differences between PaCO2 and ETCO2 and between RRd and RRm were calculated for every simultaneous set of measurements.


RESULTS
Bias, precision, limits of agreement (bias +/- 2 precisions) between PetCO2 and PaCO2 were respectively as follows: 3.1, 1.4, 0.3 to 5.9 mmHg with a Pearson correlation coefficient of 0.6 and a P value of 0.001. As for RRd v/s RRm the values were: 2, 0.5, 1 to 3 breaths per minute and 0.8 with the same P value for the Pearson coefficient.


CONCLUSIONS
Limits of agreement between PaCO2 and ETCO2 pressure and between RRd and RRm are clinically acceptable. Nasal capnography is accurate for the monitoring of ventilation in extubated morbidly obese patients, following bariatric surgery.
Yazigi
Alexandre
A
Department of Anesthesia and Intensive Care, Hotel-Dieu de France Hospital, School of Medicine, Saint Joseph University, Beirut, Lebanon.
Zeeni
Carine
C
Richa
Freda
F
Chalhoub
Viviane
V
Sleilaty
Ghassan
G
Noun
Roger
R
D000328:Adult; D000768:Anesthesia, General; D050110:Bariatric Surgery; D015992:Body Mass Index; D019296:Capnography / Q000379:methods* / Q000706:statistics & numerical data*; D002245:Carbon Dioxide / Q000032:analysis; D003422:Critical Care; D005260:Female; D006801:Humans; D007442:Intubation, Intratracheal; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D009767:Obesity, Morbid / Q000503:physiopathology* / Q000601:surgery*; D011446:Prospective Studies; D015203:Reproducibility of Results
D002245:Carbon Dioxide