Key words: scavenger system, breathing circuit , Anesthesia, vaporizer, ventilation,
During inspiration, the patient will inspire both fresh gas and gas stored in the reservoir bag or ventilator bellows. Inspired gas travels through the carbon dioxide absorber
canister, past the one-way inspiratory valve, to the patient. During exhalation, gas travels from the patient, past the one-way expiratory valve, to the reservoir bag (or ventilator bellows, depending upon the position of the bag–ventilator selector switch). The one-way valves establish the direction of gas flow in the breathing circuit. Carb
on dioxide is not rebreathed because exhaled gas is directed through the carbon dioxide absorber canister prior to being reinhaled. Fresh gas from the anesthesia machine flows continuously into the breathing circuit.
Mechanical ventilation
Anesthetic Machine Parts and Functions
Pressure Manometer : Indicates the pressure that is within the breathing circuit and the patient's airways/lungs. The pressure is normally zero
Vaporiser: Contains the anesthetic gas in liquid form, which is converted to vapour as the oxygen flows through it. Precisions settings ensure that the proper percentage of anesthetic is delivered.
Flutter Valves: Inspiratory and expiratory valves that ensure unidirectional flow of gases through the breathing circuit.
Reservoir bag: Acts as a reservoir of gases for the patient to breathe; This bag also allows us to manually ventilate a patient
Soda lime canister: Contains soda lime which absorbs the carbon dioxide and water vapour expired by the patient.
Tank Pressure Gauge: Measures the pressure of a gas (in psi or kPa), such as oxygen, contained within a tank
Oxygen Flow Meter: Regulates the volume of oxygen supplied to the anesthetic system and to the patient. The amount of oxygen delivered to the patient is measured in L/minute. This volume is determined based on the size of the patient and the type of breathing circuit being used.
Disinfecting / cleaning / sterilizing...
each of the parts that has a direct contact with the patient and its garbage must be sterilized or rejected in order to avoid infections nosocomiales
Scavenger System
Active System: As stated, an active system must be attached to some form of suction or evacuation unit, which would be the facility wall or pipeline suction. In most instances, there are separate plug-ins on the wall for scavenging suction and patient suction. Somewhere in the scavenger apparatus, there will be a means of adjusting the negative pressure from the wall, so the suction will not be too strong or too weak to be effective. Active systems need some form of negative pressure relief to ensure the suction will not be so strong as to create a vacuum within the anesthesia machine itself.
Passive system: A passive system is a low-pressure system that relies on the passive flow of gas out of the machine and is connected to some sort of egress out of the room
Conclusion
The most important piece of equipment that the anaesthesiologist uses is the anaesthesia machine. The basic function of an anaesthesia machine is to prepare a gas mixture of precisely known, but variable composition
is necesary ensure that the machine is functioning properly prior to use by (1) testing electronic and computer performance, (2) calibrating flow sensors and oxygen monitors, (3) measuring breathing circuit compliance and leakage, and (4) testing the ventilator.
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