Sensitivity and Specificity of a Novel Approach to Confirm the Depth of the Endotracheal Tube: A Pilot Study

This study aimed to explore the sensitivity and specificity an approach to confirm the depth of the endotracheal tube. It was a prospective, diagnostic study (Registration number: chiCTR-TRC-14005170) conducted in the Department of Anesthesiology of West China Hospital. A total of 100 patients underwent general anesthesia were included. The distance between the upper margin of the cuff and the manubriosternal joint (CM) and the distance between the upper margin of the cuff and the carina (CC) were measured. The accuracy of the confirmed approach against fiberoptic bronchoscopy (FOB) was evaluated. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. The correlation and agreement between CM and CC were explored. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were determined to be 94.74% (95% CI: 87.07–98.55%), 79.17% (95% CI: 57.85–92.87%), 93.51% (95% CI: 85.49–97.86%), 82.61% (95% CI: 61.22%–95.05%), respectively. The κ value was 0.75 (95% CI: 0.60–0.90). There was a significant correlation between CM and CC (P < 0.001) with a correlation coefficient of 0.91(95% CI: 0.87–0.94). Bland and Altman plots also demonstrated a good agreement between the CM and CC. This novel method may be used to confirm the depth of the endotracheal tubes.