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Objectives
Case set up
Compare cases for set up
Positions, effects on patient, risks
Fluid replacement, scavenging
Suction
Ventilator set up
Patient Positioning
Indications, precautions, complications and procedure for each of the following patient positions:
Supine
Prone
Lithotomy
Beach chair
Lateral decubitus
Supine/ fracture table
General Concepts in positioning
sedated/ anesthetized patients should not be placed in positionsthey are not comfortable in when they are awake
Compromise between what patient can tolerate structurally and physiologically, and what is required for surgical access
Physiologic instability may be magnified by rapidly moving seriously ill patients
Positioning
Bony prominences can produce ischemic necrosis of overlying tissue unless proper padding is required
Enhanced by hypothermia and hypotension
Caution particularly with ulnar nerve
Supine
Lying horizontally
Arm pressure points padded and either tucked to side or abducted
Abduct less than 90 degrees
Extend hands ventrally
Ensure perfusion to the hand, no skin to metal contact and no stretch on brachial neurovascular bundle
No compression in the axilla
Bony contacts at occiput, elbows & heals padded
Supine
Horizontal supine, minimal changes to vascular system
If tipped into trendelenburg or reverse trendelenburg, effects of gravity on blood flow significant.
Pressures change 2mmHg for each 2.5cm above or below level of the heart
Supine
Reverse trendelenburg
Blood pools in legs, decreasing effective circulating volume
Decreased cardiac output
Decreased systemic perfusion
Perfusion pressure in brain correspondingly decreased compared to if measured at level of the heart
Ventilation dynamics are enhanced
Supine
Trendelenburg
Increased pressure in cerebral veins
Can increase ICP
Congestion around eyes and airway
Negative impact on ventilation
Supine
Pregnant uterus rests on great vessels of the abdomen
Aortocaval compression- therefore tilt into Left lateral decubitus position/ left uterine displacement
Supine
Excessive flexion or extension of the spine in anesthetized patients who are placed in unique surgical positions may contribute to spinal cord ischemia and catastrophic neurological damage
Prone
Venous pooling in legs, decreased preload and decreased cardiac output
If pressure is on abdominal viscera, transmitted to veins in spinal canal, causes increased bleeding in spine procedures
Extensive spine procedures in the prone position is associated with post operative visual loss (associated with blood loss, anemia & hypotension)
Prone
Importance of secure airway
Always have stretcher outside room in case airway is lost
Congestion of face and airway
Check eyes & ears carefully
Ensure arms not extended > 90 degrees, and well padded
Lithotomy
Gynecologic and urologic procedures
Supine, arms crossed on trunk or extended laterally on arm boards
Flex lower extremities at hip and knee
Both limbs simultaneously elevated and separated
Nerve injury possible if hips flexed greater than 90 degrees
Lithotomy
Ensure padding over lower extremities if pressure points exist
Can get hypotension if legs lowered quickly or decreased effective circulating blood volume
Decreases diaphragmatic excursion and impairs ventilation
Caution with hands and watch BP when leveling table back to neutral
Lithotomy
Elevated lower extremity positions may reduce perfusion pressure in the elevated extremities
conditions for developing compartment syndromes, especially when extremities are elevated for prolonged periods
Maintain perfusion pressure to extremities
Beach Chair
Often intubated as access to airway is difficult
Ensure ETT well secured and stays in place while moving patient and bed
Caution with elevating head of table with venous pooling and hypotension
Case reports with decreased cerebral perfusion
Lateral Decubitus
Turned onto one side
(left side down = left lateral decubitus position)
Place an axillary roll just under chest to take pressure off axillary neurovascular bundle
V/Q mismatch may occur, particularly with co-existing pulmonary disease
Caution with pressure to eyes & ears
Fracture Table
For repair of fractured femur
Pelvis is retained in place by a vertical pole at perineum with the foot of the injured extremity fixed to a mobile rest
Traction is applied between the foot and pelvis
Perineal crush injury possible
Setting up the case
Assist with surgical draping, while maintaining the integrity ofthe sterile field
Avoid walking between or crossing over sterile fields
Setting up the case
Prepare, in consultation with the anaesthesiologist, medication needs for general and regional anesthesia
Emergency Drugs
Selection and preparation of medications, checked and labelled for usage as appropriate
For every case:
Succinylcholine 20 mg/ml 10mL syringe
Atropine 0.4mg/ml- 0.6 mg/ml vials, 1mL syringe
Ephedrine 5mg/ml (50mg vial/ 10cc)
Phenylephrine 100mcg/ml (10mg/100cc)
CAS monitors
Required:
Pulse oximeter
Apparatus to measure blood pressure, either directly or noninvasively
Electrocardiography
Capnography, when endotracheal tubes or laryngeal masks are inserted.
Agent-specific anesthetic gas monitor, when inhalation anesthetic agents are used.
CAS monitors
Exclusively available for each patient:
Apparatus to measure temperature
Peripheral nerve stimulator, when neuromuscular blocking drugs are used
Stethoscope - either precordial, esophageal or paratracheal
Appropriate lighting to visualize an exposed portion of the patient.
Preparation for Local/ standby
Standard CAS standard monitors in use
Anesthesia available to provide sedation
Local anesthetic as per surgeon (watch doses)
Have emergency drugs available
Preparation for Sedation
CAS monitors
Emergency drugs available, IV, oxygen
Useful to monitor capnography
Many drugs can be used to provide sedation
Midazolam
Fentanyl
Remifentanil
Ketamine
Preparation for Regional
CAS monitors
Emergency Drugs available, iv, oxygen
Again, variety of drugs may be used
Midazolam
Fentanyl
ketamine
Titrate to effect
Preparation for Regional
Neuromuscular stimulator, electrodes - ultrasound available
Surface electrode - dressing if catheter
Skin prep - local anesthetic for skin
Local anesthetic for skin infiltration - gloves
Local anesthetic for nerve block
Nerve stimulating needle for block
Preparing for Spinal/Epidural
CAS monitors, iv, oxygen may be required
Emergency drugs available - skin prep
Prepackaged trays - trays
Local anesthetic/ opiod for injection - local anesthetic
Ready to assist with patient positioning
Preparing for General Anesthesia
CAS monitors
iv fluids
Machine checked
Other lines as necessary
Emergency drugs ready
( Drugs for case ready )
Any other lines, procedures, equipment ready if anticipated
Preparing for General Anesthesia
Suction
Oxygen
Laryngoscope
ETT
Stylet
Consider Airway and location of A/W backup equipment
Emergency Situation- Anaphylaxis
ABC’s
Fluid resuscitation
Large bore iv access available
Epinephrine titrated to response
start at 10 mcg, escalate dose as required,
50-100mcg if hypotensive,
1mg ACLS dose
Emergency Situation- Anaphylaxis
H1 blocker
Benadryl 50mg
Corticosteroid
Hydrocortisone 50-100mg
Stop inciting allergen exposure
Emergency Situations- Cardiovascular Events
ABC’s
ACLS protocols
Responses dictated by clinical scenario
Crash cart available
Ensure CPR started
Emergency Situations- Increased ICP
Head of bed 30 degrees elevated
Ensure adequate cerebral venous drainage
General goals:
Avoid hypoxemia
Avoid hypotension/ maintain cerebral perfusion
CPP= MAP - ICP
Avoid abrupt hypertension
Emergency Situations- Increased ICP
Pharmacologic measures to lower ICP
Moderate hyperventilation pCO2 30-35, (short term)
Mannitol 0.5-1g/kg through 50 micron filter
Lasix 0.5mg/kg
How to manage emergencies
Malignant hyperthermia
Hypermetabolic disorder of skeletal muscle
Intracellular hypercalcemia in muscle activates metabolic pathways
Energy depletion, acidosis, membrane destruction, cell death
Heritable component, not invariably present by family history
Hallmark- hypercarbia, tachycardia, tachypnea, hyperthermia, rigidity, arrhythmias, hyperkalemia, renal failure, DIC, death
Emergency Situations- Malignant Hyperthermia
ABC’s
Ensure MH crisis issued - MH cart
Stop triggering agents - hyperventilate, 100% O2,
Finish case ASAP high flows
Dantrolene 2.5mg/kg, repeat q5min prn until 10mg/kg
(20mg mix with 60ml sterile H2O
Emergency Situations- Malignant Hyperthermia
Arterial line- blood work and blood gasses
Begin cooling patient
Treat supportively
Patient will need ongoing treatment in ICU
Determine case requirements for suction; such as:Airway suctionGastric suctionThoracic suctionSurgical suctionPost-surgical wound drainage
Suction
Airway
Have suction ready as part of any induction
Attached to bronchoscopy port
Gastric
Bowel obstructions- low intermittent suction
Cell Saver
Cell saver
Intraoperative blood salvage
Anticoagulate salvaged blood as it leaves the surgical field
Separates rbc’s from other components and debris
Washes the rbc’s for return to patient
Cell Saver
Useful for procedures with anticipated significant blood loss
Reduce the use of autologous rbc transfusion
Contraindications:
infection - malignant cells
Contamination with urine, bowel contents, amniotic fluid
Cell saver
Complications
Dilutional coagulopathy
Reinfusion of contaminants- fat, leukocytes, red blood cell stroma, air, free hemoglobin, heparin, bacteria, debris from surgical field
Anesthesia Workstation
High pressure circuit
Cylinders including N2O, O2 & Air
O2 2200psi -> 50 psi
N20 750 psi -> 50 psi
Decreased through pressure regulators
High Pressure SystemReceives gasses from the high pressure E cylinders attached to the back of the anesthesia machine (2200 psig for O2, 745 psig for N2O)
Consists of:Hanger Yolk (reserve gas cylinder holder)Check valve (prevent reverse flow of gas)Cylinder Pressure Indicator (Gauge)Pressure Reducing Device (Regulator)
Usually not used, unless pipeline gas supply is off
E Size Compressed Gas Cylinders
Cylinder Cylinder CharacteristicsCharacteristics
OxygenOxygen Nitrous OxideNitrous Oxide Carbon DioxideCarbon Dioxide AirAir
ColorColor White White (green)(green)
BlueBlue GrayGray Black/White Black/White (yellow)(yellow)
StateState GasGas Liquid and gasLiquid and gas Liquid and gasLiquid and gas GasGas
Contents (L)Contents (L) 625625 15901590 15901590 625625
Empty Weight Empty Weight (kg)(kg)
5.905.90 5.905.90 5.905.90 5.905.90
Full Weight (kg)Full Weight (kg) 6.766.76 8.808.80 8.908.90
Pressure Full Pressure Full (psig)(psig)
20002000 750750 838838 18001800
Hanger Yolkorients and supports the cylinder, providing a gas-tight seal and ensuring a unidirectional gas flow into the machine
Index pins: Pin Index Safety System (PISS) is gas specific prevents accidental rearrangement of cylinders (e.g.. switching O2 and N2O)
Anesthesia Workstation
Intermediate pressure circuit
Includes pipeline O2 and N20 at 50-55psi
Extends to flow control valves
Intermediate Pressure SystemReceives gasses from the regulator or the hospital pipeline at pressures of 40-55 psig
Consists of:Pipeline inlet connectionsPipeline pressure indicatorsPipingGas power outletMaster switchOxygen pressure failure devicesOxygen flushAdditional reducing devicesFlow control valves
Pipeline Inlet ConnectionsN2O and O2, usually have air and suction too
Inlets are non-interchangeable due to specific threading as per the Diameter Index Safety System (DISS)
Each inlet must contain a check valve to prevent reverse flow (similar to the cylinder yolk)
Low Pressure System
Extends from the flow control valves to the common gas outlet
Consists of:Flow metersVaporizer mounting deviceCheck valveCommon gas outlet
Anesthesia Workstation
Cylinder supply source is back-up if pipeline supply fails
Fail-safe valve located downstream from N2O supply sources
Interface between O2 & N20 with proportioning system
Prevent delivery of hypoxic gas mixtures
Anesthesia Workstation
High priority alarm- if O2 supply pressure is less than a critical pressure (<30psi)
Regulated flow enters low pressure circuit with adjustments in flowmeters
Gas mixture travels through a common manifold directed to vaporizer
Precise amounts of inhaled anesthetics added, controlled by dial flow
Anesthesia Workstation
Fresh gas flow with added anesthetic vapor travel to common gas outlet
Datex-Ohmeda have one-way check valves between vaporizer and common gas outlet
Prevent back flow into the vaporizer during PPV
Minimize effects of downstream intermittent pressure fluctuations on inhaled anesthetic concentrations
One-way check valve influences preoperative leak test
Pipeline Supply Source
Critical errors have occurred if incorrect supply attached to machines
Pipeline inlet fittings are gas specific with threaded fittings
Diameter Index Safety System (DISS)
If pipeline crossover suspected: turn on back-up O2 cylinder
Pipeline supply must then be disconnected
Cylinder Supply Source
E cylinders
Pin Index Safety System
Pressure reducing valve downstream
If not turned off, will be preferentially used
Volume of gas remaining in the cylinder is proportional to cylinder pressure
Oxygen supply pressure failure safety device
Designed to not allow hypoxic mixture delivery
Alarm sounds if oxygen pressure falls
O2 linked with delivery of other gasses to be oxygen dependent
If O2 pressure falls, other gas delivery falls
Flowmeters
Indicator float position is where upward force from gas flow equals downward force on float from gravity
O2 flow knob physically different from other gas knobs
N2O and O2 interfaced mechanically/ pneumatically, maximum 3:1 ratio
Oxygen flowmeter located downstream from other flowmeters in case of a leak
Limitations of Proportioning Systems
Machines equipped with proportioning systems can still deliver a hypoxic mixture under the following conditions:
Wrong supply gasDefective pneumatics or mechanics (e.g.. The Link-25 depends on a properly functioning second stage regulator)Leak downstream (e.g.. Broken oxygen flow tube)Inert gas administration: Proportioning systems generally link only N2O and O2
In general, an oxygen analyzer is the only machine safety device that can detect these problems (gas sampling done at the Y-piece of the patient circuit)
Oxygen Flush Valve
Direct communication with high pressure and low pressure circuit
Enters circuit downstream from vaporizers and from machine outlet check valve
100% O2 at 35-75 L/min (50 psi)
Potential problems: barotrauma, decreasing volatile anesthetic concentration, awareness
Oxygen Flush Valve (O2+)Receives O2 from pipeline inlet or cylinder reducing device and directs high, unmetered flow directly to the common gas outlet (downstream of the vaporizer)
Machine standard requires that the flow be between 35 and 75 L/min
The ability to provide jet ventilationvia the O2 flush valve is presence of a check valve between the vaporizer and the O2 flush valve (otherwise some flow would be wasted retrograde)
Vaporizers
Instrument designed to change a liquid anesthetic agent into its vapor and add a controlled amount of this vapor to the fresh gas flow
Important that each volatile anesthetic is in type specific vaporizer
Physical properties of volatile anesthetics
If incorrectly filled with inappropriate anesthetic, resulting output drastically changes
Vaporizers
Variable bypass- regulating anesthetic agent output
Concentration control dial determines ratio of flow through the bypass chamber and enters the vaporizer inlet
Gas channeled through the vaporizing chamber flows over the liquid anesthetic and becomes saturated with vapor
Flow over- method of vaporization
Vaporizers
Temperature compensated- maintains a constant vaporizer output over a wide range of operating temperatures
Agent specific
If vaporizer is overfilled or tilted, liquid anesthetic can spill into the bypass chamber
Final concentration of inhaled anesthetic is the ratio of the flow of the inhaled anesthetic to the total gas flow
Generic Bypass VaporizerFlow from the flowmeters enters the inlet of the vaporizer
The function of the concentration control valve is to regulate the amount of flow through the bypass and vaporizing chambers
Splitting Ratio = flow though vaporizing chamber/flow through bypass chamber
Examples include the Tec 3, Tec 4, Tec 5 and the Drager 19.1
Vaporizers- safety features
Agent- specific, keyed filling devices
Overfilling minimized because the filler port is located at the maximum safe liquid level
Firmly secured to a vaporizer manifold
Interlock system to prevent administration of >1 anesthetic agent
Desflurane’s Tec 6 Vaporizer
Because of physical properties of Desflurane, supplying it in a conventional vaporizer would lead to excessive cooling of the vaporizer
Vapor pressure is much higher than other volatile anesthetics
Much less potent (higher MAC)
Would vaporize many more volumes of Desflurane than other agents
Tec 6 electrically heated and vaporized
Tec-6 VaporizerElectronically heated and pressurized to achieve controlled vaporization of desflurane
2 independent circuits (fresh gas and vaporizer)
Vaporizer output is controlled by adjusting the concentration control valve (R2)
Pressure in the two limbs is equalized by the pressure regulating valve
Desflurane’s Tec 6 Vaporizer
Essentially a dual gas blender
By controlling the dial, the operator controls a variable restrictor valve
The Circuit: Circle SystemSo-called because the components are arranged in a circular manner
Arrangement is variable, but to prevent re-breathing of CO2, the following rules must be followed:
Unidirectional valves between the patient and the reservoir bagFresh-gas-flow cannot enter the circuit between the expiratory valve and the patientAdjustable pressure-limiting valve (APL) cannot be located between the patient and the inspiratory valve
Circle Breathing System
Prevents rebreathing of CO2 by use of CO2 absorbents
Allows partial rebreathing of other exhaled gasses
Components:
Fresh gas inflow source - CO2 absorbent
Inspiratory and expiratory unidirectional valves - reservoir bag
Adjustable Pressure Limiting (APL) valve - Y-piece connector
Circle Breathing System
Unidirectional flow
Maintenance of relatively stabile inspired gas concentrations
Conservation of respiratory moisture and heat
Prevention of OR pollution
Disadvantage is- many possible sites for misconnections and leaks
The Adjustable Pressure Limiting (APL) Valve
User adjustable valve that releases gases to the scavenging system and is intended to provide control of the pressure in the breathing system
Increased pressure in the breathing system (from patient) pushes the diaphragm off its seat venting the excess gas into the scavenging system
The control knob controls the position of the diaphragm
Bag-mask Ventilation: Valve is usually left partially open. During inspiration the bag is squeezed pushing gas into the inspiratory limb until the pressure relief is reached, opening the APL valve. At this point the additional volume the patient receives is determined by the relative resistances to flow exerted by the patient and the APL valve
Mechanical Ventilation: The APL valve is excluded from the circuit when the selector switch is changed from manual to automatic ventilation
CO2 absorber
2 clear plastic canisters arranged in series
Soda lime, Baralyme and calcium hydroxide lime
Soda lime- calcium hydroxide, water, sodium hydroxide and potassium hydroxide, silica
CO2 + H2O <-> H2CO3
H2CO3 + 2NaOH (KOH) <-> Na2CO3 (K2CO3)+2H20 + heat
Na2CO3 (K2CO3) + Ca(OH)2 <->CaCO3 +2NaOH (KOH)
CO2 Absorber
pH indicator added to assess absorbent
Changes to violet color when pH of the absorbent decreases as a result of CO2 absorption
Indicates absorptive capacity of material has been consumed
Scavenging System
Collection and subsequent removal of waste anesthetic gases from the operating room
Minimizes OR pollution by removing excess gasses
National Institute for Occupational Safety and Health (NIOSH) standards
2ppm for halogenated agent alone
25 ppm for N2O
Halogenated with N20 0.5 ppm
Scavenging SystemsScavenging Interface: Protects the breathing circuit or ventilator from excessive positive or negative pressure. There are 2 kinds of scavenging interfaces:
Open: Contains no valves and is open to the atmosphere allowing both positive and negative pressure reliefClosed: Communicates with the atmosphere through valves
Gas Disposal Assembly: This assembly ultimately eliminates the waste gas. There are 2 kinds of gas disposal assemblies:
Passive: Uses the pressure of the waste gas itself to produce flow through the systemActive: Uses a central vacuum to induce flow in the system, moving the waste gas along. A negative pressure relief valve is mandatory (in addition to positive pressure relief)
Scavenging System
Adds to OR pollution:
Failure to turn off gas flow at end of case
Poorly fitting masks, flushing the circuit
Filling vaporizers
Other circuit types which are difficult to scavenge
Scavenging System
Active or passive
Active- uses central evacuation system to eliminate waste gases
Passive- pressure of waste gas itself produces flow
Waste anesthetic gases are vented through the APL valve or through the ventilator relief valve
Scavenging System
Potential problems:
Obstruction- excessive positive pressure in the breathing circuit and barotrauma
Excessive vacuum- negative pressures within the breathing circuit
Generic Ascending Bellows VentilatorBellows physically separates the driving gas circuit from the patient gas circuit
During the inspiratory phase the driving gas enters the bellow chamber resulting in:
Compression of bellows delivering the anesthetic gases within the bellows to the patientClosure of the overflow valve, preventing anesthetic gas from escaping into the scavenging system
During the expiratory phase the driving gas exits the bellows chamber.
Exhaled gas fills the bellowsExcess gas opens the overflow valve (PEEP of 2-3 cmH2O) allowing scavenging of excess gases to occur
Machine CheckAnesthesia Apparatus Checkout Recommendations, FDA. 1993.
Categories of check:
• Emergency ventilation equipment - high pressure system
• Low-Pressure system - low pressure system
• Scavenging system - breathing system
• Monitors - final position
• Manual and automatic ventilation system
• Final Position
Preoperative Checklist- High Pressure System
Check O2 cylinder supply
-open cylinder and verify at least ½ full
-close cylinder
Check central Pipeline Supplies- check connections and pipeline gages
Preoperative Checklist- Low Pressure System
Check initial status of low pressure system- close flow control valves and turn vaporizers off- check fill level and tighten vaporizer’s filler cap
• Perform Leak Check - machine master switch and flow control valves OFF- attach suction bulb to common gas outlet- squeeze bulb until fully collapsed- verify bulb fully collapsed > 10 seconds- check same for each vaporizer
Low Pressure Circuit Leak Test
Checks the integrity of the anesthesia machine from the flow control valves to the common outlet (e.g. leaks at flow tubes, O-rings, vaporizer)
Two types of leak test (depending on presence or absence of check valve)
Oxygen Flush Positive-Pressure Leak Test: Only used in machines withoutcheck valves; basically just pressurize the low pressure circuit using the O2+ flush valve and look for leakNegative Pressure Leak Test: Used in machines with or without check valves (i.e. Ohmeda). Attach suction bulb to common gas outlet, squeeze repeatedly until fully collapsed and ensure that it remains collapsed for 10 seconds. Will detect leaks as small as 30 ml/min.
Preoperative Checklist- Low Pressure System
Turn on Machine Master Switch
Test flowmeters
- adjust flow off all gasses checking for smooth operation of floats and undamaged flow tubes
- attempt to create a hypoxic N2O/O2 mixture and verify correct changes in flow
Preoperative Checklist- Scavenging System
Adjust and check scavenging system
- ensure proper connections between scavenging system and APL valve and ventilator relief valve
- adjust waste gas vacuum
- fully open APL valve and occlude Y-piece
Preoperative Checklist- Scavenging System
- with minimum flow, allow scavenger reservoir bag to collapse completely and verify that absorber pressure gauge reads zero
- with O2 flush activated, allow scavenger reservoir bag to distend full, and verify that absorber pressure gauge reads <10 cm H2O
Preoperative Checklist- Breathing System
Calibrate O2 monitor
- ensure monitor reads 21% on room air
- verify low O2 alarm is enabled and functioning
- reinstall sensor in circuit and flush breathing system with O2
- verify that monitor now reads > 90%
Preoperative Checklist- Breathing System
Check Initial Status of Breathing System
- set switch to “bag” mode
- check that circuit is complete, undamaged and unobstructed
- verify that CO2 absorbent is adequate
- install breathing circuit accessory equipment to be used during case (HME)
Preoperative Checklist- Breathing System
Perform Leak Check of the Breathing System
- Set all gas flows to zero- Close APL valve and occlude Y-piece- Pressurize breathing system to 30 cmH2O with
O2 flush- Ensure that pressure remains fixed > 10seconds- Open APL valve and ensure pressure decreases
Preoperative Checklist- Manual and Automatic Ventilation Systems
Test Ventilation systems and unidirectional valves
-place a second breathing bag on Y-piece
-switch on automatic ventilation
-turn ventilator on and fill bellows and breathing bag with O2 flush
-set O2 flow to minimum, other gasses off
Preoperative Checklist- Manual and Automatic Ventilation Systems
- verify that during inspiration bellows deliver appropriate TV and that during expiration bellows fill completely- set fresh gas flow to approximately 5 L/min
-Verify ventilator bellows and simulated lungs fill and empty appropriately without sustained pressure and end expiration
-Check for proper functioning of unidirectional valves
Preoperative Checklist- Manual and Automatic Ventilation Systems
-switch to bag/APL mode- Ventilate manually and assure inflation
and deflation of artificial lungs and appropriate feel of system resistance and compliance
- Remove second breathing bag from Y-piece
Preoperative Checklist- Monitors
Check, calibrate and/or set alarm limits of all monitors- Capnometry- O2 analyzer- Pressure monitor with high and low A/W
pressure alarms- Pulse oximeter- Respiratory volume monitor
Preoperative Checklist- Final Position of Machine
Check final status of machine- vaporizers off- APL valve open- selector switch to “bag”- all flowmeters to zero/minimum- patient suction level adequate- breathing system ready to use
Oxygen Analyzer Calibration
only machine safety device that evaluates the integrity of the the low-pressure circuit continuously
Other machine safety devices are upstream from flow control valves
Expose O2 concentration sensing element to room air for calibration to 21%