Welcome to your Test 18 What is the color code for an oxygen cylinder in Europe according to EN ISO 407? Black body, white shoulder Green body, white shoulder Grey body, black shoulder Blue body, white shoulder None What is the pin index system used for? Regulating gas flow from the cylinder Preventing incorrect cylinder attachment Measuring pressure inside cylinders Indicating cylinder content None What is the pressure of a full oxygen E-cylinder (size D/E) at 20°C? 137 bar (2000 psi) 60 bar 4 bar 1 bar None Which of the following statements about nitrous oxide cylinders is TRUE? They contain gas only They are filled to 137 bar Pressure remains constant while liquid is present They have pin index 2,5 None The pin index for nitrous oxide is: 2,5 1,5 3,5 4,7 None What is the approximate volume of oxygen in a full E-cylinder? 200 L 500 L 660 L 1600 L None What is the pressure in an empty oxygen cylinder? 137 bar 1 bar 50 bar 4 bar None Which of the following gas cylinders is most affected by ambient temperature? Oxygen Nitrous oxide Air Heliox None The function of the Bodok seal in a cylinder yoke is to: Regulate pressure Filter gas Ensure airtight seal Lock the cylinder None Which component reduces the pressure of gas exiting a cylinder before entering the anaesthesia machine? Regulator Flowmeter Vaporizer Check valve None The pipeline pressure for oxygen supply in an anaesthesia machine is approximately: 137 bar 4 bar 1 bar 10 bar None What is the safety system that prevents misconnection of gas hoses to pipeline outlets? Pin index NIST DISS Schrader valve None In a pipeline failure, which gas source is automatically prioritized by the anaesthesia machine? Cylinder Pipeline Vaporizer Air pump None What material is typically used in medical gas pipeline construction? Steel PVC Copper Aluminium None Which of the following gases is not typically piped in hospital wall outlets? Oxygen Nitrous oxide Air Halothane None What is a major risk of pipeline cross-connection? Low pressure alarm Hypoxia Air embolism Circuit leak None What is the function of a check valve in a gas supply system? Reduces pressure Allows gas to flow one way only Vaporizes gas Measures flow None Pipeline failure should be suspected when: Flowmeter shows zero Oxygen failure alarm activates Vaporizer overflows Bellows collapse None What is the likely pipeline pressure when a wall outlet for air is working correctly? 1 bar 4 bar 10 bar 14.7 psi None In the event of pipeline gas contamination, which supply should be used? Continue with pipeline Use gas scavenger Switch to cylinder supply Turn off machine None In the anaesthesia machine, oxygen failure safety devices: Shut off nitrous oxide when oxygen fails Control vaporizer output Maintain equal flows Reduce pipeline pressure None Which flowmeter is most critical for safety? Nitrous oxide Air Oxygen Carbon dioxide None The rotameter (flowmeter) operates based on: Bernoulli’s principle Boyle’s law Variable orifice, constant pressure Constant orifice, variable pressure None What happens when the oxygen flush valve is pressed? High flow oxygen bypasses flowmeters and vaporizers Vapourized agent is added Flow reduces to patient Alarms activate None The oxygen flowmeter is placed: Upstream of other gases Downstream of other gases At the inlet Randomly None If the bobbin in a flowmeter is stuck at the bottom, what is the most likely consequence? Inaccurate low flow reading Excess oxygen delivered Hypoxic mixture delivered Vaporizer malfunction None Which of the following is a hypoxic guard system on modern anaesthesia machines? Pin index Proportioning system (e.g., Link 25) Pressure regulator Oxygen analyzer None A gas flowmeter tube is tapered because: It looks better Gas viscosity changes with pressure Area increases to maintain constant pressure drop It simplifies calibration None When using low fresh gas flows (e.g. 0.5 L/min), which of the following becomes most important? Type of vaporizer Flowmeter calibration Accuracy of O₂ analyzer Cylinder color coding None What is the minimum oxygen concentration that modern machines deliver when nitrous oxide is used? 50% 25% 21% 35% None What is the primary function of the oxygen fail-safe valve? To deliver 100% oxygen during pipeline failure To monitor oxygen concentration To shut off nitrous oxide when oxygen pressure fails To measure oxygen flow None What is the function of the second-stage pressure regulator? Controls pipeline pressure Reduces oxygen pressure to constant level Supplies gas to flowmeters Bypasses vaporizers None What property of a flowmeter allows accurate low-flow readings? Constant temperature Tapered bore Vertical alignment High gas pressure None At low gas flows, flowmeter readings depend mainly on: Pressure Laminar flow (viscosity-dependent) Turbulent flow (density-dependent) Temperature None What is the main reason why flowmeters must be calibrated for each gas? To account for gas color Different viscosities and densities Cost of calibration Availability of gas None Which gas would show the greatest flow error if oxygen and nitrous oxide flowmeters were accidentally swapped? Oxygen Nitrous oxide Air Heliox None The oxygen flush valve delivers gas at which pressure? 1 bar 2 bar 4 bar 40–60 psi (2.8–4.2 bar) None Which of the following bypasses the vaporizer when activated? Flowmeter Oxygen flush valve Common gas outlet Proportioning system None What is the most common cause of barotrauma during manual ventilation? High O₂ flow Obstructed scavenging Use of vaporizer Using oxygen flush during inspiration None What is the function of the common gas outlet (CGO)? Supplies oxygen to scavenger Delivers anesthetic gas to the breathing system Bypasses vaporizers Prevents barotrauma None What is the main role of the flowmeter? Reduce pressure Measure volume of gas Control and measure gas flow rate Oxygenate patient directly None Which vaporizer is typically agent-specific and keyed to accept only one volatile? TEC 6 Plenum Desflurane vaporizer Variable-bypass vaporizer None Why is desflurane vaporized differently than other agents? Its low boiling point High MAC value It’s not volatile Very high viscosity None Vaporizers are designed to deliver: Gas at room temperature A fixed volume of agent A constant output regardless of flow An accurate concentration of anesthetic vapor None A temperature-compensated vaporizer achieves accurate output by: Heating the agent Using electronic sensors Adjusting splitting ratio based on temperature Bypassing the vaporization chamber None If a vaporizer is tipped during transport, what should be done before use? Flush with high flow oxygen for 20 min Turn it on immediately Empty it Use nitrous oxide only None What is the function of the check valve near the CGO? Prevent backflow into machine Control anesthetic concentration Regulate cylinder pressure Calibrate vaporizer None What is the best method for detecting hypoxic mixtures? Fail-safe valve Oxygen analyzer Vaporizer accuracy None The "minimum O₂ flow" feature in modern machines typically provides: 25 mL/min 150 mL/min 200 mL/min 50 mL/min None Why should the oxygen flowmeter be placed downstream in the gas manifold? It is easier to access Reduces pipeline pressure Prevents delivery of hypoxic mixtures Ensures constant temperature None A sudden drop in oxygen pressure with no change in flow could indicate: Flowmeter error Leaky vaporizer Oxygen pipeline crossover Cylinder overfill None Which of the following gases is most likely to produce a hypoxic mixture if misconnected? Nitrogen Nitrous oxide Helium Medical air None During pre-use check, you should verify: Vaporizer smells okay O₂ analyzer calibration Patient’s weight Flowmeter float height None The O₂-N₂O proportioning device operates on what principle? Density Pressure differential Mechanical linkage Vaporization point None A leak in the low-pressure system of an anaesthesia machine is best detected by: Visual inspection Electronic alarm Negative-pressure leak test Turning off vaporizers None When using desflurane, which additional safety feature is included in the vaporizer? Lockout switch Heating element and pressure regulator External vaporization chamber Oxygen bypass None A scavenging system prevents: Barotrauma Hypoxia OR contamination by anesthetic gas Cylinder explosions None The most reliable method to prevent hypoxic gas delivery is: Color-coded cylinders Pin index system Proportioning systems + O₂ analyzer Regular vaporizer checks None A rise in back pressure in the anaesthesia machine most likely indicates: Cylinder leak Expired soda lime Obstruction in scavenging or expiratory limb Overfilled vaporizer None What is the primary purpose of the APL valve in manual ventilation? Deliver constant oxygen Prevent inhalation of CO₂ Maintain positive pressure Control circuit pressure during expiration None Time's up
