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Reg Anesth Pain Med. 2012 May-Jun;37(3):334-9. doi: 10.1097/AAP.0b013e3182475fba.

Ultrasound-guided regional anesthesia: how much practice do novices require before achieving competency in ultrasound needle visualization using a cadaver model.

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Department of Anaesthesia, St. Vincent's Hospital, Melbourne, Australia.



Ultrasound needle visualization is a fundamental skill required for competency in ultrasound-guided regional anesthesia. The primary objective of this study using a cadaver model was to quantify the number of procedures that novices need to perform before competency, using a predefined dynamic scoring system was achieved in ultrasound needle visualization skills.


Fifteen trainees, novices to ultrasound-guided regional anesthesia, performed 30 simulated sciatic nerve blocks in cadavers. After each procedure, a supervisor provided feedback regarding quality-compromising behaviors. Learning curves were constructed for each individual trainee by calculating cusum statistics. Trainees were categorized into those who were proficient, not proficient, and undetermined. A mathematical model predicted the number of procedures required before an acceptable success rate would be attained. Logistic regression was used to identify factors associated with success.


There was wide variability in individual cusum curves. The mean number of trials required to achieve competency in this cohort was 28. Trainees were categorized as proficient (n = 6), not proficient (n = 5), and undetermined (n = 4). With each subsequent procedure, there was a significant increase in the likelihood of success for trainees categorized as not proficient (P = 0.023) or undetermined (P = 0.024) but not for trainees categorized as proficient (P = 0.076). Participants recruited later in the study had an increased likelihood of success (P < 0.001).


Trainees became competent in ultrasound needle visualization at a variable rate. This study estimates that novices would require approximately 28 supervised trials with feedback before competency in ultrasound needle visualization is achieved.

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