Category: Education

Presentation Description

No description available.


Presentation Transcript

PowerPoint Presentation:


PowerPoint Presentation:


PowerPoint Presentation:

The Anaesthesia Machine The anaesthesia machine is a device which delivers a precisely-known but variable gas mixture, including anaesthetizing and life-sustaining gases.

Functioning :

Functioning gas supply gas inlet pressure reduction flowmeter vapourizer common gas outlet breathing circuit patient

PowerPoint Presentation:

vaporizer bellow Corrugated tube Soda lime Flow meteRr ventilator APL valve Scavenging system

PowerPoint Presentation:

HISTORY : • 1917 – Boyle machine with a water sight feed type of flowmeter is introduced by Henry Edmund Gaskin Boyle. • 1920 – A vapourizing bottle is incorporated to the machine. • 1926 – A 2nd vaporizing bottle and by-pass controls are incorporated. • 1930 – A Plunger device is added to the vaporizing bottle. • 1933 – A dry-bobbin type of flowmeter is introduced. • 1937 – Rotameters displayed dry-bobbin type of flowmeters

PowerPoint Presentation:

Anesthetic Machines Anesthetic machines began appearing at the end of the 19 th century Early anesthetic machines were utilized in dental anesthesia for administration of N 2 O and O 2 Initial machines were either: Continuous flow – continuous flow throughout inspiration and expiration ( eg . Heidbrink , Foregger , Boyle) Intermittent flow – flow of gas during inspiration only ( eg . McKesson) Machines evolved to incorporate reducing valves, flow meters, vaporizers and circuits with carbon dioxide absorption


Apparatus for administration of inhalational anaesthesia & O2 Provide continuous flow Part of anaesthesia workstation All machines comply with ASTM standard ANAESTHESIA MACHINE


SYSTEM COMPONENTS ELECTRICAL Master switch Power failure Reserve power Electrical outlets Circuit breakers Data communication ports PNEUMATIC HIGH PRESSURE INTERMEDIATE PRESSURE LOW PRESSURE ALTERNATIVE OXYGEN CONTROL


PNEUMATIC SYSTEM HIGH PRESSURE Cylinders Hanger Yoke Cylinder Pressure Indicator(Gauge) Pressure Regulators INTERMEDIATE PRESSURE Master Switch Pipeline Inlet Connections Pipeline Pressure Indicators Piping Gas Power Outlets Oxygen Pressure Failure Devices Gas Selector Switch Second stage Pressure Regulator Oxygen Flush Flow Adjustment Control LOW PRESSURE Flowmeters Hypoxia Prevention Safety Devices Unidirectional(Check) Valves Pressure Relief Device Low Pressure Piping Common (Fresh) Gas Outlet

PowerPoint Presentation:

The Anesthesia Machine High Intermediate Low Pressure Circuit


HIGH PRESSURE SYSTEM Receives compressed gases from cylinders at high,variable pressures and reduces it to lower,more constant pressure suitable for use in the machine Constitutes from cylinders to pressure reducing valves A) COMPRESSED GAS CYLINDERS : • made up of alloy [ steel,molybdenum(0.15 - 0.25 %),chromium] • Aluminium cylinders – MRI COMPATIBLE Nonliquefied(0 2, ,N 2 ,Air,He) • Compressed gases Liquefied(N 2 O, CO 2 )






COMPRESSED GAS CYLINDERS Different sizes – A,B,C,D,E ( E most commonly used) Filling ratio/density-percent ratio of wt of gas to the wt of water that cylinder hold at 60 0 F Service pressure- maximum pres to which cylinder may be filled at 70 F International color coding – O2 – WHITE CO2 - GRAY N2O - BLUE He - BROWN N2 - BLACK AIR - WHITE & BLACK Units of pressure( 100kPa = 760mmHg = 14.7psi =1atms )


COMPARATIVE FEATURES COLOR CODE BOILING POINT CYLINDER PRES. CAPACITY(SIZE D) CAPACITY(SIZE E) PHASE OF COMPOUND CYLINDER VALVES OXYGEN CYLINDER NITROUS CYLINDER Black with white shoulder Blue - 183 degree C -89 degree C 1900 psi 750 psi 400L 940L 600L 1600L Gaseous Liquid Diaphragm type Packing type


COMPRESSED GAS CYLINDER Testing of a cylinder : Tensile Test Hydraulic Test( every 5 years ) Cylinder markings – date of filling,service pres,manufacture’s name,transportation number,cylinder number,DOT specification,testing date




COMPRESSED GAS CYLINDER Body Components of a cylinder : Shoulder Valve Port Stem


COMPRESSED GAS CYLINDER Cylinder valve : made up of bronze/brass either packed type/diaphragm type parts – port,stem,handle,pres.relief device conical depression,pin index safety system,valve outlet connection for large cylinders . Pin index safety system- noninterchangeable O2 - 2,5 N20 – 3,5 AIR – 1,5 CO2( <7.5%)-2,6 CO2( >7.5%)-1,6 ENTONOX-7

PowerPoint Presentation:

PISS PISS (pin-index safety system) prevents misconnection of a cylinder to the wrong yoke. Keep cylinders closed except when checking machine, or while in use (if O2 from pipeline is unavailable)

PowerPoint Presentation:

cylinder size Dimensions(OD*Length in inch ) Weight (pounds) of empty cy. Oxygen N2O CO2 Air B 3.5 *13 5 200L 1900 psig 370L 838 psig D 4.5*17 11 400L 1900 940L 745 940L 838 375L 1900 E 4.25*26 14 660L 1900 1590L 745 1590L 838 625L 1900 M 7*43 63 3450L 2200 7570L 745 7570L 838 2850L 1900 G 8.5*51 97 13800L 745 12300L 838 5050L 1900 H 9.25*51 119 6900L 2200 15800L,745 6550L 2200

PowerPoint Presentation:


PowerPoint Presentation:

Pressure relief device. (safety relief device, safety device) Purpose :to vent the cylinders contents to the atmosphere if the pressure of the enclosed gas increases to a dangerous level. TYPES 1) Rupture Disc 2)Fusible Plug 3)COMBINATION OF 1 & 2 4)Pressure Relief Valve


PRESSURE RELIEF VALVE It is a spring loaded device designed to reclose and prevent discharge of cylinder contents after normal pressures have been restored There is a set pressure at which it will discharge. This is marked on the cylinder.

Handle (handwheel, key):

Handle (handwheel, key)


RULES FOR SAFE USE OF CYLINDERS No part should ever be subjected to temp. >54degree C (130F) or < -7degree C(20F) Valve is the most easily damaged part Color of the cylinder shouldn’t be relied on for identification Only one sealing washer should be used Cylinder valve should always be opened SLOWLY to prevent adiabatic process

PowerPoint Presentation:

HOW LONG BEFORE O2 TANK IS EXHAUSTED??? -The time to exhaustion is calculated by dividing the remaining O2 volume in the cylinder by the rate of consumption of O2. -Remaining volume in liters (L) in an E-cylinder is calculated by dividing the cylinder pressure in psig by 2000 psig and multiplying by 660 L.




B. HANGER YOKE PROVIDES GAS TIGHT SEAL ENSURES UNIDIRECTIONAL GAS FLOW CHECK VALVE ASSEMBLY –Allows gas from a Cylinder to enter a machine but prevents gas from exiting the machine when there is no cylinder in yoke. Placing a cylinder in a yoke – cylinder valve and yoke should not be contaminated with oil/grease Yoke checked to make certain that two pin index safety system pins are present. Most common cause of leak is defective or missing washer . SUPPORTS & ORIENTS CYLINDERS

C. Cylinder pressure indicator(Gauge):

C. Cylinder pressure indicator(Gauge) Displays the cylinder pressure for each gas scale must be at least >33 % max.filling pressure of Cylinder Also known as Bourdon’s pres.gauge Recent advances in electronics machines Digital pressure readouts LED

C. Cylinder pressure indicator(Gauge):

C. Cylinder pressure indicator(Gauge) Bourdon gauge is a device that senses pressure and converts the pressure to displacement Bourdon-pressure gauge is available in various tube shapes : curved or C-shaped, helical, and spiral. The reading indicated on a dial by the pointer is proportional to the pressure applied C - type Bourdon tubes are used for low pressure ranges and helical / spiral tubes for higher pressure ranges.


D. PRESSURE REGULATING VALVES INDICATIONS To prevent barotrauma to the patient To prevent damage to flow control valves,tubings and other parts of apparatus Continual adjustment of flow control valve would have to be made to maintain constant flow rate


D. PRESSURE REGULATING VALVE PHYSICAL PRINCIPLE A P a p TYPES Adjustable Means for the user to adjust delivery pressure Found on transport gas cylinders Preset Preset at factory Requires a tool to adjust Delivery pres.

Intermediate Pressure System:

37 Intermediate Pressure System Receives gasses from the regulator or the hospital pipeline at pressures of 40-55 psig Consists of: Pipeline inlet connections Pipeline pressure indicators Piping Gas power outlet Master switch Oxygen pressure failure devices Oxygen flush Additional reducing devices Flow control valves

Pipeline Inlet Connections:

38 Pipeline Inlet Connections It is the entry point of gases from pipelines.Mandatory for N 2 O and O 2 , also for air and suction too Inlets are non-interchangeable due to specific threading as per the Diameter Index Safety System (DISS ) fittings. Each inlet must contain a check valve to prevent reverse flow from machine to piping(similar to the cylinder yoke ) Filter present at inlet,pore size 100µm or less.

Pipeline pressure indicators:

39 Pipeline pressure indicators Needed to monitor the pipeline pressure of each gas. Usually found on a panel on the front of the machine ,may be colour coded. Should register pressure between 50-55 psig . Indicator should be on the pipeline side of the check valve in the pipeline inlet. If a cylinder valve is open and pipeline supply fails there will be no change in indicator pressure till cylinder is nearly empty. If gas pressure coming from a cylinder via a pressure regulator exceeds pipeline pressure and a cylinder valve is open, gas will be drawn from the cylinder. Cylinder valve should be closed when pipeline supply is in use.


40 Pipings Used to connect components inside the machine. Must be able to withstand 4 times higher pressure without rupturing. Leaks between pipeline inlet \ cylinder pressure reducing device and flow control valves should not exceed 25ml per minute. If pressure reducing system is included , maximum allowable leakage should not exceed 150 ml per minute.

Gas Power Outlet:

41 Gas Power Outlet Supply oxygen or air to ventilators. Check valve present. Spring loaded valve present.

Oxygen Failure Safety Devices:

42 Oxygen Failure Safety Devices Machine standard requires that an anesthesia machine be designed so that whenever the oxygen supply pressure is reduced below normal, the oxygen concentration at the common gas outlet does not fall below 19% A Fail-Safe valve is present in the gas line supplying each of the flowmeters except O 2 . This valve is controlled by the O 2 supply pressure and shuts off or proportionately decreases the supply pressure of all other gasses as the O 2 supply pressure decreases Historically there are 2 kinds of fail-safe valves Pressure sensor shut-off valve ( Ohmeda ) Oxygen failure protection device ( Drager )

Intermediate pressure system:

Intermediate pressure system

Oxygen Supply Failure Alarm:

44 Oxygen Supply Failure Alarm The machine standard specifies that whenever the oxygen supply pressure falls below a manufacturer-specified threshold (usually 30 psig ) a medium priority alarm shall blow within 5 seconds . Electronic alarms: A pressure operated electric switch operates this alarm\ Ohmeda : 28 psig Drager : 30-37 psig Pneumatic alarms (aka Bowman’s Whistle ): Uses a pressurized canister that is filled with oxygen when the anesthesia machine is turned on. When the oxygen pressure falls below a certain value, the alarm directs a stream of oxygen through a whistle

Limitations of Fail-Safe Devices/Alarms:

45 Limitations of Fail-Safe Devices/Alarms These devices depend on pressure and not flow so have limitations. Fail-safe valves do not prevent administration of a hypoxic mixture ,they do not prevent anaesthetic gas from flowing if there is no flow of O 2 . These devices prevent hypoxia from problems occurring upstream in the machine circuitry (disconnected oxygen hose, low oxygen pressure in the pipeline and depletion of the oxygen cylinder). Do not prevent hypoxia from accidents such as pipeline crossovers or a cylinder containing the wrong gas. Equipment problems that occur downstream (like leaks , partial closure of oxygen flow control valve) are not prevented by these devices.

Intermediate pressure system:

Intermediate pressure system

Second-Stage Pressure Regulator:

47 Second-Stage Pressure Regulator Located just upstream of the flow control valves Receives gas from the pipeline inlet or the pressure regulator and reduces it further to 26 psig for N 2 O and 14 psig for O 2 Purpose is to eliminate fluctuations in pressure supplied to the flow indicators caused by fluctuations in pipeline pressure

Oxygen Flush Valve (O2+):

48 Oxygen Flush Valve (O2+) Receives O 2 from pipeline inlet or cylinder pressure regulator and directs high, unmetered flow to the common gas outlet (downstream of the vaporizer) Machine standard requires that the flow between 35 and 75 L/min Single –purpose, self closing device.Designed to minimize unintentional activation.Labelled “O 2 +” . Hazards May cause barotrauma Dilution of inhaled anesthetic Accidental activation Internal leakage, Flush may stick

PowerPoint Presentation:

49 Flush valves for gases other than oxygen are not permitted. Oxygen flush can be activated regardless of whether machine is turned ON or OFF. Pressure delivered is 60 psig.

Flow adjustment controls:

50 Flow adjustment controls Controls rate of flow of gas through it’s associated flow indicator by manual adjustment of a variable orifice . Current standard requires that there be only one flow control valve for each gas. It must be adjusted or identifiable with it’s flow indicator.


51 Components Body - screws into the anaesthesia machine Stem and Seat - have fine threads,when valve is closed the pin at the end of the stem fits into the seat,occluding the orifice. - when stem is turned outward an opening between pin and stem is created allowing gas to flow. Control knob – joined to the stem.

Control Knob:

52 Control Knob Touch coded. Color coded. Joined to stem. It should be large enough so that it can be turned easily.

PowerPoint Presentation:

53 ROTATORY STYLE KNOB: F low control knob for O 2 must have fluted profile. be as large as or larger than that for any other gas. Knobs are turned counter clockwise to increase the flow and clockwise to decrease the flow. all other flow control knobs must be round. If other types of flow control knobs are present the O 2 control must look and feel different from the other controls.

PowerPoint Presentation:

54 USE : Flow control knobs should operate smoothly and be easy to adjust. Knob should be turned clockwise only until the flow of gas ceases, because further tightening may result in damage to pin/ seat . When a machine is not being used, gas source should be closed or disconnected.The flow control valves should be opened until the gas pressure is reduced to zero and then closed. Flow control valves should be checked to see that they are closed before use of machine is resumed.

Problems with flow control valves:

55 Problems with flow control valves Inadvertent alterations . Loose or worn knob - may respond to a light touch or accidental brushing. Leakage through open flow control valves . Failure to allow adequate gas flow.

Low Pressure System:

56 Low Pressure System Extends from the flow control valves to the common gas outlet Consists of: Flow meters Hypoxia prevention safety devices Unidirectional valve Pressure relief devices Common gas outlet Vaporizers and their mounting devices

PowerPoint Presentation:

The Anesthesia Machine High Intermediate Low Pressure Circuit


FLOWMETER ASSEMBLY TUBE: made of glass, Thorpe tube . Glass tubes intended for ball indicator have rib-guides which are thickened bars that run the length of tube. Rib guides hold the ball indicator in the center of tube Can have a single or double taper Single taper tube have gradual increase in diameter from the bottom to top - used where there are different tubes for low & high flow Dual taper tubes have 2 different tapers on the inside of same tube.One for fine flows and one for coarse flows - used when only one tube is used for a gas

PowerPoint Presentation:

INDICATOR: float or bobbin,made of aluminium Free - moving device within the tube if it moves erratically readings may be inaccurate In non-rotating float type reading is taken at the upper rim Bobbin is made antistatic to prevent sticking to wall of flowmeter . Rotating indicators ( rotameters ) have upper rim ,diameter of which is larger than body. Slanted grooves or flutes are cut into the rim.There is often a coloured dot on one side of indicator. When gases pass between the rim and tube wall flutes cause the indicator to rotate.Reading taken at the upper rim Ball indicator reading is taken at the ball’s mid point Types: non rotating H type,ball,rotating .

PowerPoint Presentation:

STOP: present at the top of flowmeter tube prevents indicator from plugging the outlet. Also prevents indicator from rising to a point where it cannot be seen. HAZARD: stop might break off and fall on indicator – registers less flow than is actually occuring . SCALE: is marked on or immediately adjacent to tube Flowmeters are calibrated in liters per minute

PowerPoint Presentation:

Oxygen: Graduated in 100ml/ min,divisions from 100 to 2000ml/min and in 1000ml/min divisions from 2000 ml – 5000ml/min. Carbon-dioxide: Graduated in 100ml/min divisions from 100-2000ml/min Cyclopropane : Graduated in 50 ml/min divisions from 50-750ml/min Nitrous Oxide: Graduated in 1L divisions from 1- 10 L/min Modern machines have flowmeter lights

Flowmeter :

63 Flowmeter When the flow control valve is opened the gas enters at the bottom and flows up the tube elevating the indicator The indicator floats freely at a point where the downward force on it (gravity) equals the upward force caused by gas molecules hitting the bottom of the float Because the tube is tapered the annular opening around the indicator increases with height and more gas flows around the float

Flowmeter Physics:

64 Flowmeter Physics The rate of flow through the flowmeter tube depends on 3 things Pressure drop across the constriction : As gas flows around the indicator it encounters frictional resistance between the indicator and tube wall.there is loss of energy reflected in a pressure drop. This pressure drop is given by: weight of float/cross sectional area

PowerPoint Presentation:

Size of annular opening: The annular area varies while the pressure drop across the indicator remains constant for all positions in the tube. Physical characteristics of the gas : Low Flow: Small annular space, therefore flow is laminar, therefore flow is a function of gas viscosity .(Hagen- poiseuille equation)

PowerPoint Presentation:

High Flow: Large annular space, therefore flow is turbulent, therefore the flow is a function of gas density .( Graham,s law)

PowerPoint Presentation:

Flowmeters are calibrated at atmospheric pressure (760 torr ) and room temp( 20 deg C). Changes in temp & pressure will affect density and viscosity of a gas and affect flowmeter accuracy. In a hyperbaric chamber flowmeter will deliver less gas than indicated . With decreased barometric pressure (increased altitude), the actual flow rate will be greater than that indicated.

Arrangement of the Flow-Indicator Tubes:

68 Arrangement of the Flow-Indicator Tubes In the presence of a flowmeter leak (either at the “O” ring or the glass of the flow tube) a hypoxic mixture is less likely to occur if the O 2 flowmeter is downstream of all other flowmeter In A and B a hypoxic mixture can result because a substantial portion of oxygen flow passes through the leak, and all nitrous oxide is directed to the common gas outlet


AUXILIARY OXYGEN FLOWMETER Self contained flowmeter with its own flow control valve,flow indicator,& outlet Short tube with maximum flow of 10L/min Usually on the left side of the machine Can be used to supply O 2 to patient without turning ON the machine Older machines – works on pipeline supply,in newer ,works on cylinder & pipeline supply both.


PROBLEMS WITH FLOWMETERS Inaccuracy- if mixing of components occur Indicator problems – damage due to sudden projection to top of the tube. - worn or distorted Leaks – if flow control valve is left open, there is no cylinder or yoke plug in the yoke Using the wrong flowmeter – when flowmeter sequence is altered


HYPOXIA PREVENTION SAFETY DEVICES MANDATORY MINIMUM OXYGEN FLOW: Some machines require a minimum ( 50-250ml/min) flow of O 2 before other gas will flow Some machines activate an alarm if O 2 flow goes beyond a certain minimum. MINIMUM OXYGEN RATIO: Device to protect against operator selected delivery of a mixture of O 2 & N 2 O having O 2 conc below 21% O 2 . MECHANICAL LINKAGE: Exists between O 2 & N 2 O flow control valve There is a 14- tooth sprocket on N 2 O flow control valve & 29-tooth sprocket on O 2 flow control valve

PowerPoint Presentation:

Flow control valves are adjusted so that when 25% O 2 conc is reached ,a pin on O 2 sprocket engages a pin on O 2 flow control knob.This causes O 2 & N 2 O flow control valves to turn together to maintain minimum O 2 of 25%. If attempt is made to increase the N 2 O flow beyond that ratio, the O 2 flow is automatically increased. If O 2 flow is lowered too much the N 2 O flow is decreased proportionally An electronic system can be used to provide a minimum ratio of O 2 to N 2 O flow ALARMS: Available to alert the operator that O 2 -N 2 O flow ratio has fallen below a preset value


UNIDIRECTIONAL (CHECK ) VALVE During controlled ventilation a positive pressure from breathing circuit can be transmitted back to the machine Using O 2 flush valve may also cause this Unidirectional check valves are present to minimize these effects Valve is located between vaporizers and common gas outlet ,upstream of where O 2 flush flow joins fresh gas flow


PRESSURE RELIEF VALVE May be attached downstream of vaporizers on the back bar itself or near common gas outlet Prevents high pressure being transmitted to the machine Whenever preset pressure is exceeded valve opens to atmosphere and gas is vented outside Usually opens when pressure in the back bar exceeds 35kPa This valve limits the machine to provide jet ventilation Also known as the pop-off valve .


COMMON ( FRESH ) GAS OUTLET Receives all the gases and vapors from the machine and delivers the mixture to breathing system Some outlets have a 15-mm female slip-joint fitting with a coaxial 22-mm male connector Machine standard mandates that it be difficult to accidentally disengage the delivery hose from the outlet The pressure delivered at the outlet is 5 -8 psi


BACK BAR Part of frame of the Boyle’s machine which supports the rotameter,vaporizers and other accessories There are 2 metal rods in back bar Flowmeters and vaporizers are connected with each other and then bolted with the back bar.


SAFETY FEATURES OF THE BOYLE ANAESTHESIA MACHINE Antistatic low friction black rubber wheels to the machine trolley. Cylinders : - colour coding - safety pin index system - safety relief valve - filling of cylinder Bourdon’s pressure gauze Pressure reducing valve

PowerPoint Presentation:

Flow meters : - colour,touch & placement coding - rotating bobbin - antistatic spray in flowmeters - downstream placement of oxygen flowmeter . - master and slave safety mechanism for gas delivery between N2O & O2

PowerPoint Presentation:

Radio-fluorescent plastic sheet behind flow meters Placement of vaporizers In older machines - copper plunger in Boyle’s bottle - Trilene interlock with closed circuit


Vaporizer inter-lock device Oxygen Flush Valve Sodalime and its indicator in closed circuit Black tubings of breathing system




DAILY CHECKLIST FOR ANAESTHESIA MACHINES INSPECT MACHINE Vaporizers: Turn off. Refill (if necessary). Tighten filler cap. CO2 absorber: Check fill level and usage. Replace after 10-12 hours of use. One-Way Valves (Circle system): Check function by breathing through circuit. CONFIRM OXYGEN SUPPLY IS ON Check cylinder pressure and/or piped gas lines. FLOWMETER Check bobbin/ball moves freely and spins.

PowerPoint Presentation:

PRESSURE CHECK MACHINE/CIRCUIT (each morning and any time bags or tubes are changed) Close pop-off valve. Occlude breathing tube by placing thumb over ET tube connection port. Pressurize circuit to 30cm H2O by using 3L/min O2 flow to fill bag. Turn off O2 flow and watch the pressure gauge for pressure loss. Turn on vaporizer (no O2 flow) and watch for drop in pressure. At any point, if pressure loss is detected, increase O2 flow slowly until pressure holds steady. *****FLOW ON O2 METER = RATE OF LEAK*****

PowerPoint Presentation:

Confirm that leakage does not exceed 300ml/min. If leak is >300ml/min the leak needs to be addressed. Open pop-off valve and confirm release of pressure. CHECK SCAVENGING SYSTEM Confirm connected to pop-off valve. Turn on extractor (active systems) and confirm rate of extraction. CHECK VENTILATOR FUNCTION (IF FITTED )


AMERICAN SOCIETY OF ANESTHESIOLOGISTS GUIDELINES FOR DETERMINING ANESTHESIA MACHINE OBSOLESCENCE Absolute Criteria An anesthesia machine shall be considered to be obsolete if any of the following criteria apply. I. . Lack of essential safety features A. Minimum oxygen ratio device (O2&N2O proportioning system) on a machine that can deliver nitrous oxide B. Oxygen failure safety (“fail-safe”) device C. Oxygen supply pressure failure alarm D. Vaporizer interlock device

PowerPoint Presentation:

E. Pin Index Safety System F. Non-interchangeable, gas-specific (e.g., Diameter Index Safety System (DISS)) connectors on the gas pipeline inlets II. Presence of unacceptable features A. Measured flow ( flowmeter -controlled) vaporizers (e.g., Copper Kettle, Verni-trol ) B. More than one flow control knob for a single gas delivered to the common gas outlet of the machine C. Vaporizer with rotary concentration dial such that the anesthetic vapor concentration increases when the dial is turned clockwise D. Connection(s) in scavenging system of the same (i.e., 15-mm or 22-mm) diameter as a breathing system connection III. Adequate maintenance no longer possible

PowerPoint Presentation:

Relative Criteria Consideration should be given to replacing an anesthesia machine if any of the following apply: 1. Lack of certain safety features Means to isolate the APL (adjustable pressure-limiting) valve during mechanical ventilation Oxygen flow control knob that is fluted and larger than the other flow control knobs

PowerPoint Presentation:

Oxygen flush control protected from accidental activation Main On/Off switch for electrical power to integral monitors and alarms Anti-disconnection device at the fresh gas outlet Airway pressure alarm (for detecting sustained positive pressure, negative pressure and high peak pressure)

PowerPoint Presentation:

II. Problems with maintenance III. Potential for human error IV. Inability to meet practice needs

PowerPoint Presentation:


authorStream Live Help