The Quality of Ultrasound-guided Peripheral Nerve Blocks, Nerve Injury, Bleeding Complications and Learning - a Prospective Observational Cohort Study

Introduction Peripheral nerve blocks are often used in anaesthesia. They can be used as the only method of anaesthesia during surgery or in combination with other methods, e.g., general anaesthesia and sedation. Moreover, peripheral nerve blocks are used to treat postoperative pain, alleviate pain in trauma patients, and for painful procedures.

For a method to be clinically useful, it is essential to understand the factors contributing to high success rates. It is equally important to know the complications related to the method. Finally, it is essential to establish a robust learning system where the anesthesiologists can track their nerve block performance over time and compare it to high performers and general performance. Therefore, we aim to establish a prospective and ongoing database to gain insight into 1) Factors contributing to block quality, e.g., success rate and nerve block duration; 2) Frequencies and types of nerve injuries and bleeding complications associated with the block procedure; 3) Tracking of block performance by anaesthesiologists. These three points are described in more detail below:

1. Success rate (block quality) It is difficult to get an overview of the success rates of peripheral nerve blocks. Most studies focus on one specific nerve block, and the number of included patients is often low. In addition, the block procedure is performed by a few anaesthesiologists who are highly skilled in the specific procedure. By establishing a database, including the most used peripheral nerve blocks used in different settings, i.e., surgery, perioperative pain management, and painful procedures, and by including anaesthesiologists with varying levels of experience and expertise, it will be possible to get a more detailed picture of factors that are important for achieving high success rates.
2. Complications Nerve injury. Peripheral nerve blocks are generally considered safe to use with low complication rates. However, complications can be severe and result in permanent nerve injury. Therefore, it is essential to get an overview of block-related complications and factors associated with these complications. Different regions have specific characteristics, and complications probably follow a characteristic pattern. A database with sufficient data will allow us to detail essential factors for understanding how complications develop and turn into permanent injuries.

Bleeding. Today, many patients receive anticoagulant therapy. We will, therefore, collect data on bleeding complications associated with the block procedure. 3. Learning Ultrasound-guided peripheral nerve blocks require a certain amount of skill to deposit LA in the correct place. By gathering data on block quality from individual anaesthesiologists over time it will be possible to gain insight into learning curves and factors important for learning different block procedures.

Methods Study design: Observational prospective cohort study. Setting: Initially, a single-centre study at the Department of Anaesthesiology, North Zealand Hospital. We envision to include as many centres as possible in Denmark.