Anesthetist's Techniques:
Failure to properly connect and utilize the available scavenging equipment.
Poor choice of or imperfect fitting of the facemask.
Leaving gas flows on with the breathing system disconnected from the patient.
Anesthetic equipment:
High pressure system (components between the flow meters and the high-pressure N2O source and the flow meters)
Low pressure system (components between the flow meters and the patient in the anesthesia machine and in the ventilator)
Loose, defective or absent gaskets and seals.
Worn-out or defective bags and breathing hoses.
Loosely assembled or deformed slip joints and the threaded connections.
Loose flow meter tubes.
Inadequately designed or poorly maintained scavenging system.
Spillage when vaporizers are filled.
Why Hospital Gas Monitoring?
Studies have shown numerous health effects associated with the exposure to waste anesthetic agents. These include increased risk of spontaneous abortion to females exposed to anesthetic gases in hospitals with incidence 1.5 to 2 times greater than in unexposed females. Further, other surveys have shown a possible relationship between occupational health exposure of hospital operating room personnel to anesthetic gases and the onset of toxic symptoms or mutagenic risks.
Acute effects:
Loss of concentration
Fatigue
Depression
Headache
Reproductive effects & chronic effects:
Loss of fertility
Spontaneous abortion
Miscarriage
Birth defects
Malignant diseases
Other Observations:
* These changes are only temporary and are reversed within 9 days.
For these reasons many countries have imposed recommendations for the limits of exposure to Nitrous Oxide and other anesthetic gases for already existing and for newly constructed or renovated operating rooms. Air Sampling of Hospital Gases in Operating Rooms
Air sampling in the operating room can be accomplished by instantaneously sampling with a syringe. This method will only accurately represent the personnel exposure when the air conditioning system provides ideal mixing and when the leak of the anesthetic agent is constant. Because leak rate will vary from moment to moment during clinical anesthesia, the interpretation of such samples must be made with caution.
An alternative to the instantaneous sampling is to sample over a period of time sufficient to average out the short-term variations. This "time weighted" sampling method is normally made by using personnel sampling pumps, with either temporary storage in gas tight bags or charcoal tubes; however this is ineffective to N2O. Such samples are then carried to the laboratory where the samples are treated in a Mass Spectrometer.
The disadvantage of this method is that it is time consuming and the delay between sampling and analysis result will prevent the personnel from reacting to any rapid changes in the gas concentration. For this reason, continuously monitoring of hospital gas is preferable, as this will provide the immediate concentration level at a specific point. This is illustrated in Figure 1 that is based on measurement results with continuously monitoring of hospital gas from an operating room.
This product has not be cleared by the US FDA.
