when flushing my patients supra pubic catheter , urine is coming into the syringe. This has happened twice. Bladder spasm cause this? We flush it with NS and let it drain thru tube from gravity. Should I be pushing the NS thru with the plunger instead of thru gravity? When the urine comes back into the syringe it is painful for her and she urinates thru her urethra. I know its not clogged because this happened again right after she came back from having it changed.