P106 Evaluating new and old transcutaneous CO₂ sensor performance during polysomnography

Abstract Introduction Transcutaneous CO₂ (TcCO₂) monitoring helps detect hypoventilation during polysomnography, but sensor performance may deteriorate over time. We assessed whether a TcCO₂ sensor operating beyond the manufacturer’s stated useful life (old: >36 months) negatively impacts performance compared to a newer sensor (new: <12 months). Methods In this prospective, observational study, 19 patients undergoing polysomnography were monitored concurrently with both the same new and old TcCO₂ sensors. We measured mean TcCO₂ values, T90 response times, and subjective signal quality. Data analysis included paired t-tests, F-tests, Bland–Altman analyses, and Chi-Square tests. p<.05 was significant. Results Mean TcCO₂ values (n = 19) did not differ significantly between the new and the old sensors (40.6 ± 4.8 vs. 39.2 ± 4.9 mmHg, p=.17). The variance of the two sensors was also not significantly different (F-test ratio of 0.60; Levene’s test p=.975). Bland–Altman of TcCO₂ values (n = 19) showed only a small bias with a mean difference of +1.25 mmHg, but with wide limits of agreement (-6.31 to +8.92 mmHg), indicating substantial variability between the two sensors. The new sensor demonstrated a faster T90 response time (45.0 ± 4.9 vs. 95.9 ± 14.4 s, p<.0001) and better subjective signal quality (84.2% vs. 47.4% good quality, X2 = 5.73, p=.017) compared to the old sensor. Conclusion TcCO₂ values showed no significant difference between a new and old sensor, despite relatively large variability in agreement. However, deterioration in response time and subjective signal quality demonstrate a worse performance of the old sensor. Further research using multiple TcCO₂ sensor pairs is needed to determine if findings are consistent and broadly applicable.