Using Bladder Scanner when does it indicate catheterization

you are using the scanner to evaluate the patient for urinary retention. this often happens in patients who have some degree of neurogenic bladder (http://www.healthsystem.virginia.edu/uvahealth/adult_urology/neurblad.cfm). so, the scanner is a tool being used to assist the healthcare professional and tell them how much urine is present in the bladder. why is that important to know? at what amount of urine in the neurogenic bladder is the person going to begin to "dribble" urine and have an incontinence problem? the other concern is how long do you want the patient to go without emptying the bladder of urine? what is the danger of urine sitting for long hours in bladder? think about the requirements that an infection needs to thrive and what is going on with someone who has the kind of condition that causes them to have a neurogenic bladder and who is being intermittently catheterized. how long do you want to leave the urine that accumulates in that bladder?