Development and characterization of a point-of care rate-based transcutaneous respiratory status monitor

Abstract

Blood gas measurements provide vital clinical information in critical care. The current "gold standard" for blood gas measurements involves obtaining blood samples, which can be painful and can lead to bleeding, thrombus formation, or infection. Mass transfer equilibrium-based transcutaneous blood gas monitors have been used since the 1970s, but they require heating the skin to ≥42 °C to speed up the transcutaneous gas diffusion. Thus, these devices have a potential risk for skin burns. Here we report a new generation of noninvasive device for respiratory status assessment. Instead of waiting for mass transfer equilibrium, the blood gas levels are monitored by measuring the transcutaneous diffusion rate, which is proportional to blood gas concentration. The startup time of this device is almost independent of skin temperature, so the measurement can be made at any body temperature. The test results show that this device can track the blood gas levels quickly even at normal body temperature.

Carbon Dioxide Sensing—Biomedical Applications to Human Subjects

“…The NDIR track was then dropped until the mid-2010s and the advent of rate-based approaches by the team of Chatterjee, Ge, Iitani et al [ 317 , 318 , 319 , 320 ] at first and by the team of Grangeat et al [ 321 , 322 ] in a second move. If the latter work is insufficiently detailed—especially the explanations concerning the sensing part itself—the former allows for a sound understanding of the rate-based approach.…”

“…Thus, NDIR sensing can be used instead of a dye-based thin film, with better lifetime, accuracy, and selectivity over the latter. These advantages made NDIR sensing the foremost choice of the authors who considered using a rate-based approach for transcutaneous CO sensing [ 317 , 318 , 319 , 321 , 322 ].…”

What do masks mask? A study on transdermal CO2 monitoring

“…Fig. 1 B shows a simplified diagram of previously developed rate-based TrCO 2 measurement system [17] . The system automatically repeats a purging process with pure N 2 aeration for 30 sec and recirculation for 60 sec.…”

Real‐time dissolved carbon dioxide monitoring I: Application of a novel in situ sensor for CO2 monitoring and control

“…Versilon F‐5500‐A tubing, which is reported to have significantly low CO 2 diffusivity, was used to connect the system components together (shown as black lines in Figures ). The electronics for activating the valves and digitizing the readings of the sensors are controlled by a dedicated microcontroller, which is also responsible for communicating the data to the computer (Ge et al, ). The program is written in LabVIEW, which controls the valves, reads the sensors, logs the data, and calculates the slopes in real‐time.…”