Learning Curves

Although many of the variables that influence the outcome of medical procedures (such as lumbar epidural blocks) to be learned cannot be included in the model that defines the learning curve, the use of a curve to show the progress of learning a particular task over time is the most practical way to describe how quickly the operator’s performance is improving. The analysis of LC-CUSUM (learning curve-cumulative sum technique) can be used to assess competence in practical procedures in the medical field by establishing an acceptable and unacceptable failure rate at the beginning of the process, providing a clear graphic representation of the trend of outcomes of a series of consecutive procedures (epidural blocks) performed over time. The LC CUSUM curve can be used to analyze epidural block performance observing one subject for the progression of several skills such as the number of attempts (number of times the Tuohy needle is completely retracted and reinserted from and into the skin before finding the epidural space), the number of redirections (number of trajectory changes without completely retracting the needle from the skin before finding the epidural space), and the number of times the epidural block results in an anesthesia success (decrease in pain from uterine contraction). Despite some limitations, CUSUM analysis is a powerful tool for the evaluation of medical staff performance, allowing for timely corrections and/or improvements.