SCAVENGING SYSTEM By Dr Ahmed Mostafa Assist Prof
SCAVENGING SYSTEM By Dr. Ahmed Mostafa Assist. Prof. of anesthesia and I. C. U.
Definition Scavenging is the collection and removal of vented anesthetic gases from the OR. Since the amount of anesthetic gas supplied usually far exceeds the amount necessary for the patient, OR pollution is decreased by scavenging. Scavenger and operating room ventilation efficiency are the two most important factors in reduction of waste anesthetic gases (WAGs).
Types 1. Active (suction applied): Active systems require a means to protect the patient's airway from the application of suction, or buildup of positive pressure. 2. Passive (waste gases proceed passively down corrugated tubing through the room ventilation exhaust grill of the OR): Passive systems require that the patient be protected from positive pressure buildup only.
Components of the scavenger system
Components of the scavenger system 1. Gas collection assembly: (tubes connected to APL and vent relief valve). 2. Transfer tubing (19 or 30 mm, sometimes yellow color-coded). 3. Scavenging interface: It is the most important component. It protects the breathing circuit from excess positive or negative pressure.
Components of the scavenger system 4. Gas disposal tubing: (carries gas from interface to disposal assembly). 5. Gas disposal assembly: (active or passive - active most common, uses the hospital suction system).
Components of the scavenger system Scavenging interface: It is the most important component. It protects the breathing circuit from excess positive or negative pressure. Positive-pressure relief is mandatory to vent excess gas in case of occlusion distal to a closed interface. . If active disposal system must have negative pressure relief as well. Reservoir highly desirable with active systems.
Components of the scavenger system Scavenging interface: The scavenger interfaces may be: A. Open (to the atmosphere): Are found on most new gas machines. Are safer for the patient. Has no valves, and is open to atmosphere. It should be used only with active systems
Components of the scavenger system Scavenging interface: B. Closed: Gases within the interface may communicate with the atmosphere only through valves; the older type).
Hazards of scavenging 1. Obstruction distal to interface causes barotrauma or excess negative pressure (action: disconnect gas collection tubing from back of pop-off valve [APL], or turn off suction at scavenger interface). 2. Occupational exposure. 3. Barotrauma or inability to ventilate.
Avoiding waste gas exposure Good mask fit. Avoid un-scavengeable techniques if possible (insufflation). Prevent flow from breathing system into room air (only turn on agent and nitrous oxide after mask is on face, turn them off before suctioning). Washout anesthetics (into the breathing circuit) at the end of the anesthetic.
Avoiding waste gas exposure Don’t spill liquid agent. Use low flows. Use cuffed tracheal tubes when possible. Check the machine regularly for leaks. Disconnect nitrous oxide pipeline connection at wall at the day’s end (beginning? ). Total intravenous anesthesia.
THANK YOU Dr. Ahmed Mostafa
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