Constructing a Learning Curve in Ultrasound Guided Needling - an Observational Study Using Cumulative Sum (Cusum) Analysis

Constructing a learning curve in ultrasound guided needling

Observational study - How many attempts, with continuous training and feedback, at in-plane ultrasound guided needling in a phantom model are required to attain competence?

The use of ultrasound to enable real-time needle visualisation during regional anaesthesia (placing local anaesthetic, via a needle, near nerves to result in numbing of an area of the body to be operated on) has gained in popularity in recent years. It has been recognised by NICE (National Institute for Clinical Excellence) and guidelines on training have been published, with UK equivalents pending. These call for training in the technique on models or 'phantoms' prior to patient contact.

It is unknown how much experience is necessary to attain competence in a phantom, prior to proceeding to patient contact. One study looking at experiential learning of the technique found a very wide range of experience needed between individuals.

In order to study the effect of any changes in training methods on the learning of the technique it is necessary to have a baseline learning curve.

The investigators are introducing a training package for anaesthetists new to the technique to meet the recommendations on initial phantom based training. Alongside this the investigators aim to gather prospective observational data allowing the investigators to generate a learning curve for the technique. This involves making a video recording of the ultrasound images of approximately 50 sequential attempts at performing a task in a phantom, with ongoing instruction and coaching. The whole training package will take approximately 1 hour.

These video clips will be reviewed and sequential attempts graded for quality of needle visualisation and task completion. This will allow the investigators to use a statistical method, Cumulative Sum (Cusum) analysis, to determine how many attempts were required to attain proficiency. The investigators hope to recruit approximately 20 participants to this pilot study, and from this determine the average amount of training necessary to attain proficiency. Using Cusum analysis requires the use of an acceptable failure rate, usually chosen arbitrarily. To add greater meaning to our findings the investigators will also invite anaesthetists experienced in the technique of in-plane ultrasound guided needling to participate. By measuring the actual success rate of our local trainers the investigators will be able to make a meaningful comparison of the training required to achieve a similar level of success.