Improvement in Validity and Reliability of Airway Assessment Using Ultrasonography by Novice Personnel: A Learning Cohort Study

PURPOSE: To assess improvements in the validity and reliability of novices’ skills in performing ultrasonography for airway assessment. PATIENTS AND METHODS: A learning cohort study was conducted with 20 anesthesiology residents and 10 volunteers in the Department of Anesthesiology, Faculty of Medicine, Prince of Songkla University. The four parameters of airway assessment were soft tissue thickness at the level of 1) hyoid bone (STT-HY), 2) true vocal cords (STT-VC), 3) thyroid isthmus (STT-TI), and 4) suprasternal notch (STT-SN). The magnitude of discrepancies between the residents’ and experienced anesthesiologists’ measurements was evaluated over the sequence of measurements in the 10 volunteers. RESULTS: The mean ultrasonic measurements of STT-HY by the experienced anesthesiologists and residents were significantly different (11.09 ± 3.14 mm vs 8.53 ± 3.02 mm, respectively; P = 0.008), whereas measurements of STT-VC, STT-TI, and STT-SN were not (7.18 ± 1.70 vs 7.14 ± 1.93, P = 0.32; 7.81 ± 2.14 vs 7.73 ± 2.19, P = 0.62; and 11.32 ± 3.33 vs 10.30 ± 3.02, P = 0.35, respectively). The mean discrepancy between the residents’ and experienced anesthesiologists’ measurements was close to zero throughout the sequence of measurements of STT-TI and STT-VC. However, the residents’ measurements of STT-HY and STT-SN were considerably lower than those of anesthesiologists. The range of discrepancies between residents and experienced anesthesiologists in each sequential measurement was wide for all measurements, particularly for the measurement values of STT-HY, and the standard deviation of the discrepancies did not decrease over the sequence of measurements. CONCLUSION: Over the sequence of measurements for airway assessment in 10 volunteers by 20 residents in this learning trial, we found no evidence of improvement in measurement accuracy. Discrepancies between the residents’ and anesthesiologists’ measurements and the variability in discrepancy across residents were greatest in the measurement of STT-HY.