BACKGROUND: Transcranial color-coded duplex sonography (TCCD) is a non-invasive bedside tool with broad diagnostic potential in the intensive care setting. Implementation of TCCD requires repeated reliable measurements of flow velocities despite data acquisition by multiple operators with varying experience. Thus the learning curve of TCCD and agreement of measurements between experienced and inexperienced operators is of great interest and unstudied so far.
METHODS: Six untrained ICU-residents and 2 trained operators participated and performed TCCD examinations of the mean cerebral artery (MCA) in 10 volunteers. Measurements of the residents were compared to the according measurements of the trained operators. Operators were either actively supervised during their first five examinations or performed the examinations without supervision.
RESULTS: A total of 480 measurements were obtained. Mean flow velocity (MFV) did not differ significantly between trained and untrained operators in the two groups (p= 0.78 in not-supervised and p=0.82 in supervised group). We found a favorable learning curve in both groups (ICC 0.8, CI 95% 0.6-0.91- in not supervised and ICC 0.81 CI 95 % 0.63 - 0.92 in supervised group). However, supervision helped trainees to acquire skills more rapidly and to perform more accurate measurements (ICC 0.77 (95% CI 0.39-0.94) to ICC 0.91 (95% CI 0.77-0.98) and ICC 0.66 (95% CI 0.11-0.91) to ICC 0.84 (95% CI 0.58-0.96) respectively).
CONCLUSION: TCCD of the MCA in volunteers is an easy to learn tool with a favorable learning curve. A short term learning program including initial supervised measurements yields reliable results in the hands of inexperienced operators.