Technical validation of the EMMA capnometer under hyperbaric conditions.

Area of Science:

• Hyperbaric Medicine
• Critical Care Monitoring
• Respiratory Physiology

Background:

• End-tidal carbon dioxide (ETCO₂) monitoring is crucial for intubated patients in critical care.
• Standard ETCO₂ monitoring devices face challenges in hyperbaric environments.
• The EMMA mainstream capnometer's performance under hyperbaric conditions was investigated.

Purpose of the Study:

• To evaluate the accuracy and functionality of the EMMA mainstream capnometer under hyperbaric conditions.
• To determine if the EMMA capnometer is suitable for monitoring ETCO₂ during hyperbaric oxygen therapy.

Main Methods:

• The EMMA capnometer was compared to a reference Philips IntelliVue M3015B microstream capnometer.
• Testing involved calibrated gases with varying CO₂ concentrations at atmospheric pressure (101 kPa).
• Device performance was then assessed at hyperbaric pressures ranging from 121 kPa to 281 kPa.

Main Results:

• At 101 kPa, the EMMA capnometer showed a mean difference of -2.5 mmHg compared to expected CO₂.
• The EMMA capnometer functioned accurately up to 281 kPa, demonstrating a linear relationship with expected CO₂.
• Over-reading of CO₂ was observed above 141 kPa, with increased variance at therapeutic hyperbaric pressures.

Conclusions:

• The EMMA capnometer is functional up to 281 kPa in hyperbaric settings.
• Despite over-reading above 141 kPa, a linear relationship between expected and measured CO₂ was maintained.
• The EMMA capnometer shows potential clinical value for monitoring expired CO₂ during hyperbaric oxygen treatments.