High Pressure System
Color coding of gases
This simulation uses the U.S. color coding by default with tank and outlet colors indicating oxygen and nitrous oxide. The international (ISO) color code and others may be selected by clicking on the "Gas Color Codes" link to the right of the animation.
The simulation shows Quick connectors for O2, N2O and vacuum, which can be connected and disconnected by clicking with the left button of a mouse.
The Pin Index Safety System is used on size E and smaller cylinders.
The pins protruding from the cylinder yoke of a particular gas have
a unique configuration that fits into corresponding holes in the cylinder
valve. This prevents the misconnection of cylinders to the wrong yokes.
This secondary function of the cylinder pressure regulator can be observed in the simulation. For example, if the oxygen cylinder is open, the higher O2 pipeline pressure closes the pressure regulator and prevents gas from flowing from the cylinder. If the O2 pipeline supply is then disconnected, oxygen can then flow through the pressure regulator.
Can the cylinder pressure gauge indicate that
an empty cylinder is full?
To observe this behavior of the cylinder pressure gauge in the simulator, open and close the oxygen cylinder with the O2 pipeline supply connected. The cylinder pressure will indicate a positive pressure but will not drop back to zero when the cylinder is closed again. When the O2 pipeline supply is disconnected and an O2 draw is created using the flush valve or the O2 flow control valve, the cylinder pressure gauge will display zero again.
Function of the fail-safe device
The action of the fail-safe device can be observed in the simulation when the O2 supply (pipeline or cylinder) is shut off with the N2O supply (pipeline or cylinder) still present.Function of the low pressure alarm
The low pressure or oxygen supply failure alarm will go off when there is a significant increase or decrease of the O2 supply pressure. This occurs when there is a sudden loss of cylinder or pipeline pressure or when the anesthesia machine is turned on or off. A commonly used mechanism utilizes a pressurized canister that is filled with oxygen when the anesthesia machine is turned on. The stream of oxygen that goes into the canister passes through a whistle, and a sound can be heard when the machine is turned on. If the oxygen pressure then falls below a certain value, this canister will empty and direct a reverse stream of oxygen through the whistle. This alarm may not be heard if the O2 supply pressure drops very gradually over a long time.
The low pressure alarm can be heard in the simulation by disconnecting and then reconnecting the O2 pipeline supply (with the O2 cylinder closed).
Ventilator drive gas circuit dependence on pressurized
The flow of oxygen can be traced from its source in the simulation. Part of the oxygen flow can be seen entering the drive gas circuit and compressing the bellows.
Using the oxygen flush
The lungs will overinflate and flash red in the simulation when the oxygen flush in continuously pressed during the inspiratory phase of mechanical ventilation.O2 flush button pressed during mechanical ventilation and expiration
If the oxygen flush is pressed during the expiratory phase of mechanical ventilation, the bellows will initially fill rapidly to its maximum capacity. After reaching maximum capacity, any pressure in excess of 2-4 cm H2O will be vented through the pressure relief valve.
The ventilator pressure relief valve underneath the bellows can be seen to open during the expiratory phase of mechanical ventilation.Inability to use O2 flush for jet ventilation
Despite the high flow rate that can be obtained by pressing the O2 flush, it is actually not the best choice for jet ventilation during cricothyrotomy. A significant pressure drop occurs across the O2 flush valve, which significantly diminishes the tidal volumes delivered to the patient during jet ventilation through the narrow bore (high flow resistance) of the needle. An auxiliary ball-in-tube oxygen flowmeter mounted on the anesthesia machine and supplied with 50 psig O2 is the recommended mode of administering O2 during jet ventilation. Even though the flowrate through the ball-in-tube flowmeter typically does not exceed 15 L/min, the pressure drop is lower across the ball-in-tube flowmeter when it is wide open. The higher outlet pressure from the ball-in-tube flowmeter makes it more suitable for use in jet ventilation.
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