They weren't. The ultrasound was given to physicians and Dr. Wiss, who I know well, is an expert and a teacher of trauma ultrasound. The reason it's not given to medics at the moment is that it requires a fair amount of training and exposure to real patients with different pathology. You can imagine the problems if someone is not familiar and they read it as having blood and there's not blood. Then it actually causes more problems. Or if you read it as a false negative when it was a positive it causes more problems. Hence, that's one of the reasons why Downsview is trying to develop an automated diagnosis program for the finding of blood.
So it was never deployed in the field for medics because of the training burden that it would imply for the med techs.