Evaluation of a dual-function pH and PCO2 in vivo sensor

Area of Science:

• Biomedical Engineering
• Physiological Monitoring
• Sensor Technology

Background:

• Continuous monitoring of blood pH and partial pressure of carbon dioxide (PCO2) is crucial for managing critically ill patients.
• Existing methods often require intermittent blood sampling, which can be invasive and provide delayed results.
• Development of reliable in vivo sensors for real-time acid-base status assessment is an ongoing area of research.

Purpose of the Study:

• To evaluate the performance of a newly developed dual-function sensor for measuring systemic arterial pH and PCO2.
• To assess the sensor's accuracy and reliability during continuous in vivo monitoring in an animal model.

Main Methods:

• A dual-function pH and PCO2 sensor was implanted in the femoral arteries of anesthetized dogs.
• Sensor measurements were compared with simultaneous blood samples analyzed by a bench instrument over a 7-hour period.
• Data from 207 pH and 212 PCO2 comparisons were statistically analyzed.

Main Results:

• The sensor demonstrated high accuracy for pH, with a mean difference of 0.0003 pH +/- 0.061 SD from the bench instrument.
• The sensor showed good accuracy for PCO2, with a mean difference of -1.43 mmHg +/- 5.17 SD from the bench instrument.
• The sensor maintained performance across various acid-base conditions, including acidosis and alkalosis.

Conclusions:

• The evaluated dual-function sensors are effective for trend monitoring of blood pH and PCO2 for at least 7 hours without recalibration.
• These sensors show potential as reliable in vivo devices for blood gas analysis, valuable for both research and clinical settings.
• Improvements in sensor construction consistency could further enhance their reliability for in vivo applications.