This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anaesthesia
True about scavenging action in OT – 
Select and explain. 
A. Outlet connection is 22 mm male fitting, B. Interface limit pressure is 0 to +2 cm H2O, C. The charcoal as an adsorbent should not be used, D. Scavenging is defined as the collection of excess gases from equipment used in administrating anesthesia or exhaled by the patient and removal of these gases to an appropriate places discharge outside the working environment
D: Scavenging is defined as the collection of excess gases from equipment used in administrating anesthesia or exhaled by the patient and removal of these gases to an appropriate places discharge outside the working environment
Answer: D: Scavenging is defined as the collection of excess gases from equipment used in administrating anesthesia or exhaled by the patient and removal of these gases to an appropriate places discharge outside the working environment 
Explanation: Scavenging system is to eliminate exhaled gases from OT to minimize theatre pollution. Maximum permissible concentration of N2O in theatre is 25 ppm and that of halogenated agents is less than 2 ppm.