2.2. Difficult venous access simulator
SECONDARY
A simulator was developed especially for this study (Kyoto Kagaku Co., Japan) (Fig. Difficult venous access simulator. (a) Simulated vessels cannot be seen in the simulator with the eye. (b) Near-infrared imaging with the simulator, allowing 1 to see simulated vessels. (c) Ultrasound imaging with the simulator providing a view of simulated vessels.Punctures continued until 3 consecutive successful attempts were made. Even if 3 consecutive successful attempts were not achieved, the trial was terminated after 20 attempts. Three consecutive attempts were hypothesized to represent proficiency with the technique. Success was defined when water in the lumen of the simulated vessel was aspirated from the catheter after placement. Failure was defined as failure to place the catheter into the simulated vessel within 3 minutes, or not to achieve 3 consecutive successes within 20 attempts. The procedure time was defined as the time from the start of puncture to confirmation of water backflow from the simulated vessel. Participants performed the puncture using the assigned method (near-infrared or ultrasound), then performed using the other method (crossover study).The primary outcome measure of the study was the rate of successful first attempts, and the secondary outcome measures included procedure time and the number of 3 consecutive successful attempts. Data were electronically stored in an anonymized manner.