Anesthesia Machine Flashcards
1
Q
- Pipeline gases are supplied at pressures of about ______ psi:
A. 25
B. 40
C. 50
D. 75
A
- C. Pipeline gases are supplied at pressures between 45 and 55 psi. This is in contrast to cylinder gas pressures, which are much higher, and are reduced by pressure regulators to less than 50 psi.
2
Q
- Which of the following prevents delivery of hypoxic gas mixture once the oxygen pressure falls below 25 psi?
A. Diameter index safety system
B. Pin index safety system
C. Inspiratory check valve
D. Fail-safe valve
A
- D. The fail-safe valve automatically closes nitrous oxide (and other gases) to prevent delivery of hypoxic gas mixture to the patient. The fail-safe valve is designed to be activated when oxygen pressure falls below 25 psi.
3
Q
- The oxygen-flush valve provides which of the following oxygen flows (L/min) to the common gas outlet?
A. 10
B. 25
C. 50
D. 90
A
- C. The oxygen-flush valve provides gas flow at pipeline pressures of about 45 to 55 psi at 35 to 75 L/min. The high flow of oxygen is provided directly to the common gas outlet, bypassing the flowmeters and vaporizers. One should be careful when using the oxygen-flush valve, as high gas flows at high pressures can cause lung barotrauma in the patient.
4
Q
- Gas flowmeters
A. Are gas-specific
B. Have a gas flow rate which depends on viscosity at high turbulent flows
C. Have a gas flow rate which depends on density at low laminar flows
D. Are cylindrical in shape
A
- A. Gas flowmeters are calibrated for a particular gas. Gas flow rate depends on its viscosity at low laminar flows, and its density at high turbulent flows. Flowmeters are tapered in shape, with the diameter the smallest near the bottom of the tube.
5
Q
- Which of the following flowmeters is situated nearest to the gas outlet?
A. Nitrous oxide
B. Oxygen
C. Air
D. None of the above
A
- B. The oxygen flowmeter is situated nearest to the gas outlet. This is because, if a leak develops in the flowmeter tubes, a hypoxic gas mixture can be delivered to the patient. To minimize this, the oxygen flowmeter is positioned downstream and nearest to the gas outlet.
6
Q
- Modern vaporizers are
A. Agent-specific
B. Temperature-compensated
C. Pressure-compensated
D. Both A and B
A
- D. Modern vaporizers are agent-specific and temperature-compensated. Also, specific fillers are available for each volatile agent, which prevent filling on the wrong agent. A constant concentration of agent is delivered, unaffected by temperature or flow rates. Temperature compensation is achieved by a metallic strip composed of two different metals, which expands/contracts to deliver a constant concentration of vapor.
7
Q
- The Tec 6 desflurane vaporizer
A. Is electrically heated to 39°C
B. Is pressurized to 3 atm
C. Is pressure-compensated
D. All of the above
A
- A. The Tec 6 desflurane vaporizer is electrically heated to 39°C and pressurized to 2 atm. This is done because desflurane boils at room temperature at sea level (1 atm). The heating and pressurization optimizes the delivery of desflurane.
8
Q
- Variable bypass vaporizers should be located
A. Between the common gas outlet (upstream) and the flowmeters (downstream)
B. Between the flowmeters (upstream) and the common gas outlet (downstream)
C. Between the gas pipeline and the flowmeters
D. Inside the circle system
A
- B. Vaporizers are located between the flowmeters (upstream) and the common gas outlet (downstream). In other words, vaporizers are located outside the circle system. This decreases the likelihood of delivery of high vapor concentrations when using the oxygen-flush valve.
9
Q
- A standing or ascending bellow is preferred for anesthesia ventilators, as disconnection is indicated by
A. Collapse
B. Filling by gravity
C. Disconnection alarm
D. Stoppage of flowmeter gas
A
- A. An ascending bellow collapses when disconnection occurs. A descending bellow, however, continues to fill by gravity when disconnection occurs. Therefore, ascending bellows are preferred for anesthesia ventilators.
10
Q
- The National Institute for Occupational Safety and Health (NIOSH) recommends limiting operating-room concentration of nitrous oxide to ______ ppm:
A. 10
B. 25
C. 50
D. 100
A
- B. NIOSH recommends limiting operating-room concentration of nitrous oxide to 25 ppm. Minimizing operating-room pollution is important to prevent health-related effects in health-care providers. Waste-scavenging systems are utilized to decrease operating-room pollution.
11
Q
- The National Institute for Occupational Safety and Health (NIOSH) recommends limiting operating-room concentration of volatile inhalational agents to ______ ppm:
A. 0.2
B. 0.5
C. 1
D. 2
A
- D. NIOSH recommends limiting operating-room concentration of volatile agents to 2 ppm. Minimizing operating-room pollution is important
12
Q
- Capacity of an oxygen “E” cylinder is approximately ______ L:
A. 500
B. 600
C. 650
D. 750
A
- C. The capacity of an “E” cylinder of oxygen is about 625 to 700 L. The pressure in a full cylinder is about 1,800 psi at 20°C. Cylinders are color-coded, with oxygen being green, nitrous oxide being blue, and air being yellow.
13
Q
- If pressure in a full nitrous oxide “E” cylinder is 745 psi at 20°C, the pressure in a half-full cylinder will be about ______ psi:
A. 186
B. 248
C. 372
D. 745
A
- D. Pressure in a half-full “E” cylinder of nitrous oxide will still be 745 psi. Nitrous oxide is present in the cylinder as a liquid, and therefore, the volume remaining in the cylinder does not reflect the pressure in the cylinder. Capacity of an “E cylinder” of nitrous is about 1590 L. It is not until three-fourth of the gas is consumed (about 400 L remaining) that the pressure in the cylinder begins to fall. Therefore, the reliable way to determine the remaining nitrous oxide in the cylinder is to weigh the cylinder. The empty weight of the cylinder is stamped on the cylinder.
14
Q
- Which of the following system prevents the wrong gas cylinder being attached to the anesthesia machine?
A. Diameter index safety system
B. Pin index safety system
C. Hanger yoke assembly system
D. Gauge-safety system
A
- B. Cylinder manufactures have adopted the pin index safety system, which prevents attachment of wrong gas cylinder to the anesthesia machine. The diameter index safety system prevents attachment of the wrong gas hose from the wall supply. Hanger yoke assembly is the method of attachment of gas cylinders to the anesthesia machine.
15
Q
- A line-isolation monitor
A. Warns that an electrical shock is imminent
B. Warns of a fault between the power line and the ground
C. Warns of the presence of two faults
D. Trips the ground leakage circuit breaker
A
- B. A line-isolation monitor, when alarming, indicates that a single fault has occurred between the power line and the ground. As soon as the alarm is triggered, the equipment should be checked, especially the last equipment that was plugged in. A single fault does not cause an electrical shock, as two faults are required to produce a shock.