The Science Journal of the American Association for Respiratory Care

2008 OPEN FORUM Abstracts

ASSESSMENT OF END TIDAL CO2 DURING PEDIATRIC AND ADULT SEDATION FOR ENDOSCOPIC PROCEDURES.

Daniel Yarchi2, Ayala Cohen3, Tatiana Umansky3, Ron Shaoul1



Background: Pulse oximetry has become the standard of care during endoscopic procedures despite the fact that significant alveolar hypoventilation may be undetected.

Objective:
to study the value of end tidal CO2 measurement during pediatric and adult endoscopic procedures under general anesthesia (GA) and conscious sedation (CS). Methods: Oridion™ Microcap™ Hand Held Capnography using Smart Bite Bloc™ with O2 delivery have been used for the procedures. Microstream® non-dispersive infrared (NDIR) spectroscopy is used to measure the concentration of molecules that absorb infrared light in CO2 exhaled by the subject. For each patient we defined an "event" according to recorded parameters (pulse rate, respiratory rate, saturation and end tidal CO2).
Patients: We studied 57 patients, ages ranged between 4-62 years. Nineteen (33.3%) had CS and 38 (66.6%) had GA.

Results:
Twenty patients had no events, 32 had 1 event and 5 patients had 2 events. The highest observed frequency of an event was noted during upper endoscopy under GA (0.35), followed by upper endoscopy under CS (0.32). Fitted univariate logistic regression models indicated that higher variability in ETCO2 is associated with a higher probability for an event, p<.0001, and that an increase in age is associated with a lower probability for an event, p<.0001. Significant differences in the frequencies of SPO2 events were related to the type of procedure p=0.0002, (highest estimated probability for upper endoscopy) and GA (p<0.0001). Similar conclusions were obtained based on the fitted multivariate model.

Conclusions:
ETCO2 contributes significantly to the prediction of events during endoscopy. Lower mean of ETCO2, higher variability of ETCO2, younger age, general anesthesia and upper endoscopy increase the probability of an event.