Nitrous oxide does not affect automated air tonometry in children.

Area of Science:

• Anesthesiology
• Critical Care Medicine
• Pediatric Surgery

Background:

• Automated air tonometry is a method for measuring gastric CO2 (PrCO2).
• Nitrous oxide is commonly used in general anesthesia.
• The effect of nitrous oxide on automated air tonometry in pediatric patients is not well established.

Purpose of the Study:

• To evaluate the impact of nitrous oxide on automated air tonometry in pediatric patients undergoing general anesthesia.
• To determine if nitrous oxide affects PrCO2 readings obtained via automated air tonometry.

Main Methods:

• Ten children aged 1-3 years undergoing elective surgery received general anesthesia.
• Anesthesia was induced using sevoflurane with either oxygen/nitrous oxide (30%/70%) or oxygen/air (FIO2 0.3).
• Gastric CO2 (PrCO2) and end-tidal CO2 (PETCO2) were measured, and the Pr-ETCO2 gap was calculated to account for changes in PaCO2.

Main Results:

• Switching from nitrous oxide/oxygen to air/oxygen decreased balloon pressure by 10.4%.
• Switching from air/oxygen to nitrous oxide/oxygen increased balloon pressure by 6.4%.
• No significant changes in the calculated Pr-ETCO2 gap were observed during gas mixture changes.

Conclusions:

• Nitrous oxide does not significantly affect air tonometric PrCO2 readings in pediatric patients.
• Automated air tonometry can be safely used in conjunction with nitrous oxide during general anesthesia in children.
• These findings support the clinical utility of automated air tonometry in pediatric anesthesia settings where nitrous oxide is administered.