Monitoring ICP in the OR.

I am new to PACU and have been an ICU for 8 years. I recently recieved a patient in the PACU with a ventric that was connected to a pressure bag. I have never experienced it being set up with a pressure bag and have been taught that it was contraindicated. The reason being is that the pressure bag adds 2 mls an hour to keep the line open. Unfortunately the pressure bag also was heparinized. I immediately stated my concerns and then spoke with Anesthesia in regards to my concerns. They stated that this is normal in the OR, because the drainage system is open. They monitor the ICP for brief periods and then shut it off. Does anyone have any resources in regards to this? Is this contraindicated to attach a pressure bag? I believe the heparin is an unsafe practice d/t many reasons i.e. HIT and bleed to be the most concern.