Apex- Anesthesia Machine

Question 1

Where does the high pressure system begin and end?

intermitediate pressure system?

low pressure system?

Answer 1

Cylinders → Cylinder Regulators

Pipeline → Flowmeter VALVES

Flowmeter TUBES → common gas outlet

Question 2

What tests the integrity of the low-pressure circuit from the flowmeter valves to the common gas outlet?

how is it done?

what would signify an issue?

Answer 2

low-pressure leak nest

attach a bulb to the CGO and create neg pressure

• must be performed with teh vaporizers off, and then again with each vaporizer turned on one at a time
• if the bulb inflates, theres a leak in the system

Question 3

Components of the high-pressure system (4)

Answer 3

Question 4

Components of the intermediate-pressure system (7)

Answer 4

Question 5

Components of the low-pressure system (4)

Answer 5

Question 6

Pipeline vs tank psi

Answer 6

Pipeline = 50
Tank = 45

Question 7

T/F: when doing a low-pressure leak test, the FGF must be off

Answer 7

True

if you have a vent with a minimum FGF- you have to turn off the machine to do the test

Question 8

when doing a low-pressure test, should you be on the bag or vent?

Answer 8

bag

low pressure tests from flowmeter VALVES to CGO

Question 9

How often should the low-pressure test be performed?

Answer 9

before the first case of each day

lol

Question 10

PISS vs DISS

Answer 10

PISS- pin index - prevents wrong cylinder
DISS- diameter index - prevents wrong pipeline

Question 11

PISS configurations for Air

O2

Nitrous

Answer 11

Air 1,5

o2 2,5

nitrous 3,5

Question 12

The O2 cylinder pressure drops from ~2,000psi to what psi upon entry into the intermediate system

why?

Answer 12

~45 psi

to ensure gas is preferentially puplled from the pipeline if a cylinder is left open
(pipeline ~ 50psi)

Question 13

Why should there only be one washer between the hanger yoke assembly and the stem of the tank?

Answer 13

bc more than one may allow for the PISS system to be bypassed

Question 14

Service pressure and max volume of:

O2

Air

N20

Answer 14

O2= 1900psi/660L

Air = 1900psi/625L

N20= 745psi/ 1590L

Question 15

service pressure of nitrous oxide

Answer 15

745psi

1590L

Question 16

maximum volume of nitrous oxide in an e-cylinder

Answer 16

1590L

745psi

Question 17

why does nitrous oxide exist as a liquid inside the cylinder?

Answer 17

bc it’s critical temp is above room tempearure (~36.5)

-critical temp is the highest temp a gas can exist as a liquid

Question 18

How many L of nitrous oxide gas is remaining in the tank when there is no more liquid present

what about 400psi

Answer 18

250L

400psi = 136L

Question 19

t/f: the cylinder valve is the most delicate component of the cylinder

Answer 19

True

the silver part on top - this is why a cylinder needs to be stored in an upright position
bc if it falls down and goes boom, and the top silver piece breaks off (the cylinder valve) - the o2 tank becomes a missle

Question 20

why do we need to stand up the cylinder tank in a locked postion when not in use? what wil lhappen if it falls?

Answer 20

if it falls, the cylinder valve (the top silver piece) can break off (it’s delicate) and then the o2 tank can become a missle

Question 21

What makes a o2 tank MRI safe and how can you tell that it is?

Answer 21

-made of aluminum
-mainly silver with the top portion being the color of the gas it contains (green = o2)

*but the best way to determine the contents is to READ the label- not examine the color

Question 22

What kind of safety relief device is made by woods metal

what’s in woods metal

when would it provide safety and how?

Answer 22

fusible plug

BLT with Cheese- Bismuth, Lead, Tin, Cadmium

in the event of a fire, it would melt, to slowly release o2 contents - instead of exploding

Question 23

What’s in woods metal

Answer 23

Bismuth
Lead
Tin
Cadmium

BLT with Cheese

Question 24

Weight of a full nitrous oxide tank vs empty

Answer 24

full = 20.7#
empty= 14.1#

oh come on

Question 25

World Health Organization colors for Air, O2, and Nitrous

Answer 25

Air = black and white O2 = white Nitrous = blue

Question 26

Does Carbon dioxide exist as a liquid or gas inside the cylinder | max volume? ## Footnote service pressure?

Answer 26

liquid | 1590L (same as nitrous) ## Footnote 838psi

Question 27

T/F: if youre changing the cylinder on the andesthesia machine, it's ok to lay the cylinder on its side temporarily

Answer 27

True

Question 28

If you remove a cylinder from the anesthesia machine but don't have a replacement, what do you have to do?

Answer 28

Insert a yoke plug

Question 29

If you open the cylinder and hear a hissing sound- what does that indicate and what do you need to do?

Answer 29

leak -tighten the connection

Question 30

T/F: if there is a leak, add an additional washer between the cylinder and hanger yoke assembly

Answer 30

FALSE- dont do this - allows bypassing PISS

Question 31

Which gases are oxidizers | fire triangle components?

Answer 31

nitrous oxide and oxygen | oxidizer, fuel, igniter

Question 32

Gas cylinder should never be exposed to temps above what degrees (F + C)

Answer 32

130 degrees F 57 degrees C

Question 33

why shouldn't you oil the cylinder valve

Answer 33

bc it increases risk of fire

Question 34

What would happen if you didn't insert a yoke plug in an empty cylinder spot?

Answer 34

If the check valve were to fail & there is no cylinder or yoke plug - gas that should be going to the patient will exit the anesthesia machine

Question 35

Match: American Society for Testing and Materials (ASTM), FDA, OSHA, DOT: -sets the standards for the required components of the anesthesia machine -sets standards for compressed gas cylinders -sets standards for acceptable occupational exposure to volatile anesthetics -creates standard machine checkout procedures

Answer 35

-sets the standards for the required components of the anesthesia machine - ASTM -sets standards for compressed gas cylinders- DOT -sets standards for acceptable occupational exposure to volatile anesthetics- OSHA -creates standard machine checkout procedures- FDA

Question 36

A cylinder must be tested how often? | it's tested to how many times it's service pressure?

Answer 36

every 5 years -10 years with a specia permit indicated by a 5-pointed star on the label | 1.66x it's service pressure

Question 37

7 pieces of information required on the cylinder label according to US DOT

Answer 37

1. Government agency (DOT) 2. type of metal 3. max filling pressure 4. serial number 5. manufactorer 6. owner 7. date of last inspection

Question 38

What monitors for low oxygen pressure in the anestheisa machine | another name for it ## Footnote 3 instances it would alarm

Answer 38

Oxygen-Pressure Failure Device | Fail-safe device ## Footnote 1. depleted o2 tank 2. drop in pipeline pressure 3. disconnected o2 hose

Question 39

T/F: the failsafe device will alarm in the setting of an o2 pipeline crossover

Answer 39

False- the failsafe device monitors pressure - not o2 concentration

Question 40

2 components of the failsafe device (o2 pressure failure device) | does it reside in the high, intermediate, or low pressure system?

Answer 40

1. **a threshold alarm **that sounds when o2 pipeline pressure falls below **28-30psi** 2. A Pneumatic device that *reduces or stops the flow of nitrous oxide *when the pressure in the o2 pipeline falls *below 20psi *

Question 41

Does the fail-safe device monitor pressure or concentration

Answer 41

pressure

Question 42

What would you do if you suspect a pipeline cross over? 2 steps

Answer 42

1. open o2 cylinder on machine 2. disconnect o2 pipeline from machine

Question 43

Which machines failsafe device stops nitrous commpletely when o2 psi < 20 vs proportionatlly : drager vs GE Datex-Ohmeda)

Answer 43

Drager - proportional decrease GE Datex-Ohmeda - all or nothing

Question 44

How would you know if the o2 pressure failure device is working?

Answer 44

okay so the o2 pressure failure device alarms when psi <30 apex says to turn on o2 and nitrous flow verify o2 cylinder is closed then d/c the o2 pipeline once o2 source is disconnected, watch the flow meeters and the nitrous oxide flow should stop before the o2 flow stops retinruducing the o2 pipeline should result in both gases restored to previous flow rates

Question 45

The hypoxia prevention safety device will: A. Shut off the flow of nitrous oxide if the o2 supply pressure is < 30psi B. limit the nitorus flow to 3x the o2 flow C. Alarm if the Fio2 is < 21% D. prevent a hypoxic mixture if a third gas is used

Answer 45

B

Question 46

When you're administering nitrous oxide, the proporitioning device ensure that the FiO2 never drops below what % ?

Answer 46

25%

Question 47

The proportioning device maintsins a max of what ratio of nitrous to o2?

Answer 47

3:1

Question 48

T/F: the proportioning device will prevent hypoxia with the administration of a third gas

Answer 48

False | ie) helium

Question 49

T/F: the o2 pressure failure device and the hypoxia prevention safety device are not the same thing

Answer 49

True ## Footnote pressure failure device = fail-safe device hypoxia prevention safety device = proporitoning device

Question 50

What is the oxygen-ratio monitor controller

Answer 50

monitors the ratio of o2 to n20 (drager machine) automatically adjusts n20 to go no grater than 3:1 (pneumatic device)

Question 51

What is another name for the proportion device?

Answer 51

Hypoxia prevention safety device

Question 52

The internal diameter of the flow tubes are (narrowest/widest) at the base and (narrows/widens) with ascent

Answer 52

narrowest at the base widens as it goes up

Question 53

To monimize the risk of hypoxic mixture in the setting of a cracked flowmeter, the O2 flowmetere should be positionined where? | where is this location on US machines?

Answer 53

closest to the common gas outlet | Far right

Question 54

T/F: flowmeters are calabritated for each specific gas

Answer 54

True

Question 55

What is the space between the ball float and the wall of the flowmeter called

Answer 55

the annular space

Question 56

T/F: glass flowmeters resists the buildup of static electricity

Answer 56

True

Question 57

Should o2 be positioned first or last in the sequence of flowmeters

Answer 57

last/downstream | ie) closest to the CGO/pt ## Footnote incase there is a crack in any of the upstream flowmeters - this prevents a hypoxic mixture but a crack in the o2 flow meter can still produce a hypoxic mixture

Question 58

At high FGF, gas flow is (turbulant/laminar) and depdendent on gas (density/viscostiy) - what law ## Footnote At low FGF, gas flow is (turbulant/laminar) and depdent on gas (density/viscosity) - what law

Answer 58

High FGF- turbulent- density- grahams ## Footnote Low FGF - laminar, viscosity, pousilles

Question 59

What is the o2% delivered with 1L air and 3L o2

Answer 59

80% ## Footnote [Air flow rate x 21) + (O2 flow rate x 100)] / Total flow rate 1 x 21 = 21 + 300 = 321/4 = 80.25

Question 60

O2 nasal cannula %s: 1L- 2L- 3L- 4L- 5L- 6L-

Answer 60

1L- 24% 2L- 28% 3L - 32% 4L- 36% 5L - 40% 6L - 44% ## Footnote RA = 21% - then just go to 24% and add by 4

Question 61

% of O2 delivered with a nasal cannula can range from what

Answer 61

24-44%

Question 62

Steps in figuring out tidal volume with FGF is coupled to it

Answer 62

1. convert FGF from L/min to ml/min 2. multiply FGF by I:E ratio 3. Calculate the tv per breath (FGF/RR) 4. Add volume set on vent to FGF during inspiration ## Footnote * I:E ratio of 1:2 means over 1 minute, 20 seconds is spent in inspiration and 40 in expiration * said another way, 1/3 spent in inspiration and 2/3 spent in exhalation * so for #2- if I:E ratio is 1:2, your multipling by 1/3 or 0.33333

Question 63

A vent if programmed to deliver a tidal volume of 600mls. If the breathing circuit compliance is 5ml/cm H20 and the peak pressure is 25cm H20, what is the total tidal volume delivered to the patient? A. 425mls B. 450mls C. 475mls D. 500mls

Answer 63

C. 475 mls ## Footnote 5ml/cmh20 x 25cm H20 = 125ml 600 - 125ml = 475mls *when the vent produces postive pressure inside the breathing circuit, some of this gas causes the circuit to expand. This quantiy of gas doesnt reach the patient and doesnt contribute to the tidal volume the pt recieves

Question 64

Change in volume/ Change in pressure = what?

Answer 64

compliance

Question 65

The isoflurane dial is set to 2%. What % of fresh gas exiting the vaporizing chamber is saturated with isoflurane? Enter your answer as a percentage

Answer 65

100% ## Footnote Modern variable bypass vaporizers split fresh gas into 2 parts: 1. some fresh gas enters the vaporizing chamger and becomes 100% saturated with the volatile agent 2. The rest of the fresh gas bypasses the vaporizing chamber and does not pick up the anesthetic vapor Before leaving the vaporizer, these two fractions mix, and this determines the final anesthetic concentration exitin the vaporizer

Question 66

What does it mean when a vaporizer is "variable bypass?"

Answer 66

it means when fresh gas enters the vaporizer, someo f it encounters the liquid anesthetic and the rest bypasses it. You determine the splitting ratio (how much fresh gas contacts the liquid) by setting the concentration on the dial.

Question 67

What does it mean when a vaporizer is "flow-over"

Answer 67

so as fresh gas enters the vaporizing chamber with the liquid anesthetic, it flows over a series of baffles and wicks. The baffles and wicks increase surface area and turbulence, ensuring the fresh gas incide the vaporizing chamber becomes 100% saturated with the anesthetic agent ## Footnote variable bypass vaporiziers: **-flow-over wick** -temperature compensated -out-of-circuit -agent specific

Question 68

T/F: the temperature compensating valve on a vaporizer adjusts the ratio of the vaporizing chamber flow to bypass flow and guarantees a constant vaporizer output over a wide range of temperatures

Answer 68

True ## Footnote variable bypass vaporiziers: -flow-over wick **-temperature compensated** -out-of-circuit -agent specific

Question 69

T/F: the variable bypass vaproizer is positioned OUTSIDE of the breathing circuit

Answer 69

true ## Footnote variable bypass vaporiziers: -flow-over wick -temperature compensated **-out-of-circuit** -agent specific

Question 70

T/F: variable bypass vaporizers are agent specific

Answer 70

True - each vaporizer is calibrated to one anesthetic agent. Fillling a vaporizer with the incorrect anesthetic can lead to catastrophic errors in output ## Footnote variable bypass vaporiziers: -flow-over wick -temperature compensated -out-of-circuit **-agent specific**

Question 71

T/F: variable bypass vaporizers automatically compensate for vaporizer output at changes in elevation

Answer 71

True

Question 72

Vapor pressure is (directly/inversely) proportional to temperature

Answer 72

directly proportional ## Footnote increased temp = increased vapor pressure

Question 73

What describes the # of calories needed to convert 1g of liquid into vapor without causing a change in temp

Answer 73

Latent heat of vaporization

Question 74

What is the most common cause of a vaporizer leak? | what could it result in?

Answer 74

a loose filler cap | awareness

Question 75

What is the most common cause of a vaporizer leak? | what could it result in? ## Footnote what part of the machine check would detect a vaporizer leak?

Answer 75

a loose filler cap | awareness ## Footnote a low pressure system check (with the bulb)

Question 76

How do you calculate how much liquid anesthetic your using per hour in mls?

Answer 76

volume % x FGF (L/min) x 3

Question 77

What can happen if the vaporizer is tipped?

Answer 77

liquid anesthetic can spill from the vaporizing chamber to the bypass chamber --> this can increase vaporizer ouptut and result in anesthetic OD

Question 78

1mL of liquid produces howmany mLs of anesthetic vapor?

Answer 78

200mls

Question 79

what 2 things should you do if a vaporizer tips ## Footnote how do you know when it's okay to use again?

Answer 79

1. drain the vaporizer to remove the anesthetic liquid 2. turn the dial to it's highest % (8) and run high FGF through it for 20~30mins ## Footnote when the end tital agent reads 0

Question 80

What's it called when the gas that has left the vaporizerl, re-enters it, thereby increasing the concentration of anesthetic leaving the vaporizer? | what 2 things can lead to this? ## Footnote what eliminates this concern?

Answer 80

the pumping effect | PPV + use of the o2 flush valve ## Footnote The presence of a check valve between the vaporizer and the CGO

Question 81

Flows less than what or greater than what can lead to reduced vaporizer output?

Answer 81

flows less than 200ml/min or > 15L/min

Question 82

Does a variable bypass vaporizer need to be calibrated for elevation?

Answer 82

no

Question 83

What best describes the TEC 6 vaporizer (select 2) -It is pressurized to 2 atmospheres - It uses a flow-over design - it is heated to 42 degrees - its ouptut is increased inside a hyperbaric chamber

Answer 83

-it's pressurized to 2 atmospheres -its output is increased inside a hyperbaric chamber ## Footnote -it injects anesthetic vapor into the fresh gas (not flow-over design) - it's heated to 39 degrees (not 42) - output varies inversely with elevation (high elevation, decreased pressure, decreased ouput; low evelvation, high pressure, high output) *therefore, the vaporizer should be re-calibrated when itis going to be used in high-altitude locations

Question 84

The Tec 6 is heated to what temp

Answer 84

39 degrees C

Question 85

Des's vapor pressure and boiling point ## Footnote significance?

Answer 85

Vapor pressure = 669mmHg Boilign point = 22.8 degrees C ## Footnote vapor pressure very close to ATM (760) boiling pont very close to room temp *makes it des very volatile and very difficult to control at room temp; so small changes in room temp can signficantly alter vaporizer output

Question 86

Why is Des heated? | what is it heated to

Answer 86

bc it's boiling point is close to room temperature making it's output difficult to control at room temp -any increases or decreases in room temp would alter the output | 39 degrees C ## Footnote allows for a more controlled, consistent output

Question 87

Which device will be the FIRST to detect an oxygen pipeline crossover? A. Proportioning system B. O2 analyzer C. Fail-safe D. pulse-ox

Answer 87

B. oxygen analyzer

Question 88

Is the oxygen analyzer located i nthe inspiratory limb or expiratory limb?

Answer 88

inspiratory limb

Question 89

T/F: the oxygen analyzer can detect a hypoxic mixture caused by a leak in the oxygen flowmeter

Answer 89

True

Question 90

What is the last line of defense agaisnt a hypoxic mixture?

Answer 90

The oxygen analyzer

Question 91

What would be some causes of reduced FiO2 during low flow anesthesia?

Answer 91

Sepsis, pai, SNS stimulation, thyrotoxicosis, fever, ect ## Footnote *average o2 consumption for hte adult is 250ml/min - these situations increase oxygen demand, and can creat a hypoxic mixture during low flow anesthesia

Question 92

T/F: if there is a suspected pipeline crossover, you should immediately ventilate with an Ambu with the auxillary o2 flowmeter

Answer 92

False! -turn on your backup tank and d/c the pipeline from the machine ## Footnote the auxiliarry o2 will be the same o2 supply

Question 93

What supplies the auxillary o2 on the anesthesia machine?

Answer 93

the pipeline

Question 94

If theres question of a pipeline crossover- you should re-caliibrate the o2 analzyer

Answer 94

false ## Footnote worse to assume equipment malfunction and spend time troubleshooting - just assume it's the real thing and crack open your o2 tank and d/c the pipeline from the machine

Question 95

The o2 analyzer alarms, you open the o2 tank and d/c the pipeline from the machine...now what ?

Answer 95

verify that the o2 concentration in the circuit is increasing | -once concentration is increasing, conserve tank by using low fllows ## Footnote - if not, ventilate with an AMBU connected to a different O2 tank - also get hep to start setting up a TIVA *reconnect the pipeline ONLY after the supply has been tested

Question 96

What should be at the top of your differential when the o2 analyzer alarms?

Answer 96

pipeline crossover until proven otherwise ## Footnote dont assume equpiment malfunction!

Question 97

T/F: the O2 flush valve delivers a continuous pressure of 35-75psi

Answer 97

FALSE- READ! 35-75L/min @ 50psi (pipeline pressure)

Question 98

If your going to hit the o2 flush valve, what resp phase should you hit it in and why

Answer 98

the expiratory phase -the ventilator spill valve is closed during the inspiratory phase -pressing the o2 flush during the inspiratory phase transfers this pressure to the patients lungs (risk of barotrauma)

Question 99

Other than barotrauma, what other issue could occur with excessive use of the o2 flush valve?

Answer 99

awareness ## Footnote the gas from the o2 flush valve does not pass through the vaporizers and will dilute the partila pressure of the volatile agent and could lead to awareness

Question 100

T/F: you can use the o2 flush valve for jet ventilation

Answer 100

false- most manufacturers don't recommend it ## Footnote but some still do it as "off label" use

Question 101

Explain drive gas and pneumatic bellows during inspiration and expriation

Answer 101

During inspiration: -Drive gas flow builds pressure in the chamber, creating a pressure gradient that pushes fresh gas into the lungs - the increased pressure also closes the spill valve, ensursing vt goes to the pt and not the scavanger During expiration: -the drive gas flow stops, intrathroacic pressure builds, and once it exeeds the pressure in the chamber, the patient is able to exhale and refill the bellows -when the circuit pressure > 2-4cm h20, expired gas is directed through the spill valve to the scavanger

Question 102

2 functions of the drive gas on a pneumatic ventilator

Answer 102

1. compresses belllows 2. opens and closes the ventilator spill valve (regulate gas that goes to the scavanger)

Question 103

What is hte position of the ventilator spill valve during inspiration? ## Footnote why?

Answer 103

closed ## Footnote ensures that the tidal volume goes to the patietn and not to the scavenger

Question 104

What is the minimum expiratory pressure needed to open the ventilator spill valve ?

Answer 104

3cm H20

Question 105

Select the true statments about the pneumatic ventilator bellows (select 2) -a descendings bellows is made safer by fresh gas coupling -a descendings bellow cannot rise and fall with a circuit disconnect -a leak in the bellows may cause the reading on the o2 analyzer to increase -a hole in the bellows may caue barotrauma

Answer 105

-a leak in the bellows may cause the reading on the o2 analyzer to increase -a hole in the bellows may caue barotrauma ## Footnote a descendings bellows may continue to rise and fall in the event of a circuit disconnect - resh gas decoupling helps solve this problem

Question 106

Fresh gas flow decoupling vs coupling

Answer 106

decoupling = tv set is what the patient receives coupling = total Vt = Vt set on vent + FGF during inspiration - volume lost to circuit compliance

Question 107

Gas inside the bellows = Exhaled tidal volume + what | (vents that couple FGF)

Answer 107

Exhaled tv + FGF during expiration

Question 108

T/F: the piston ventilator incorporates the resevior bag into the ventilator circuit during mechanical ventilation

Answer 108

True! | I guess this is how you can gell if it's pneumatic vs piston bellows

Question 109

since piston ventilators incorprate the resevior bag during ventilation, when would the bag inflate/deflate and why

Answer 109

inflates during inspiration → bc excess fresh gas is diverted into the gag deflates during expiration

Question 110

with a piston ventilator, you lose your etco2 and suspect a circuit disconnect- whats something you could look out that would alert you to a circuit disconnect?

Answer 110

the resivor bag - if it's deflated - there is probably a disconnect (it inflates with inspiration) ## Footnote so i guess if you lose etco2 and ur bags still inflated, the vent is still delivering breaths but something else is going on - like a bronchospasm or tube migration

Question 111

Which type of vent has postive and negative pressure relief vales - pneumatic or piston?

Answer 111

piston

Question 112

when does the postive pressure relief valve open | what type of vent ## Footnote purpose?

Answer 112

+75cm H20 | piston vent ## Footnote decreases risk of barotrauma (doesn't eliminate)

Question 113

when does the negative pressure relief valve open | what type of vent ## Footnote what happens when it opens? issue?

Answer 113

-8cm h20 | piston ## Footnote room air is entrained into the breathing circuit to protect agaisnt negative end expriatory pressure this additional room air can dilute o2 and anesthetic concentrations

Question 114

why do descending bellows continue to fill during a circuit disconenct?

Answer 114

bc they will entrain room air

Question 115

T/F: a gas-driven bellow automatically adds 2-3cm of peep

Answer 115

true - due to the design of the ventilator spill valve

Question 116

T/F: the piston ventilator automaticall y adds 2-3cm of peep

Answer 116

fasle - gas driven vent due to the ventilator spill valve

Question 117

T/F: in a piston driven vent, if the pt is spontaneously breathing- the breathing bag will not inflate/deflate

Answer 117

true - only inflates/deflates when breaths are delivered by the ventilator

Question 118

Which statement fregarding PCV is true (select 2): -The risk of ventilator-associated lung injury is decreased -increased lung compliance will decrease Vt -gas flow decelerates during inspiration -the ventilator switches to expiration after a preset pressure is achieved

Answer 118

- the risk of vent-associated lung injury is decreased - gas flow decelerates during inspiration ## Footnote -bc preak pressure is fixed and tidal volume is variable, an increase in lung complicance will increase the Vt -the vent achieves a peak pressure very early in the inspiratory cycle and holds it for a time determined by the I:E ratio → therefore it does not immediately cycle after the peak pressure is achieved

Question 119

If your using volume control, what are you watching for cues regarding your patients compliance/degree of anesthesia ## Footnote what about if your using pressure control?

Answer 119

watching for changes in peak pressures ## Footnote pressure control- your watching for changes in volumes

Question 120

In inspiratory flow variable on VCV or PCV?

Answer 120

PCV- initially high to reach preset pressure then slows down to maitnain a cosntant pressure

Question 121

Which is more effective in reducing the risk of ventilator-associated lung inury - PCV or VCV ?

Answer 121

PCV

Question 122

Which vent mode would be better for a patient with low compliance? | 4 examples

Answer 122

PCV | pregnant, fat, laproscopic surgery, ARDS

Question 123

Which vent mode would be best if you needed to compensate for a leak with an LMA?

Answer 123

PCV - want to CONTROL the pressure and not go above 20 or you could insulflate the abdomen

Question 124

Which modes of mechanical ventilation are BEST duited for an LMA? (select 2): -SIMV -Inverse ratio ventilation -PSV -Controlled mandaroy ventilation

Answer 124

-SIMV and PSV

Question 125

difference b/t pressure control vs PC with volume guarentee

Answer 125

pressure control- you adjust pressure and see wehre volumes land PC-VG- guantees a pre-determined tidal volume and will apply the minum pressure required to achoive it | good for compliance changes intraop like laparoscopic surgery ## Footnote not quite sure how this differs from Volume contorl -you have a preset volume and it applies the minimum pressure required to achieve it

Question 126

What is SIMV?

Answer 126

A vent mode where you set a TV and RR but it allows the pt to breath spontaenously between machine breathes and the machine will coordinate with the pt breaths to meet the minimum minute ventilation

Question 127

What does the "pro" in PSV- pro stand for?

Answer 127

protect -if pt is spontaneously breathing - they will receive PSV -if they become apneic, the vent will convert to PCV -when they start spontaneously ventilating, the vent will go back to PSV

Question 128

Difference between PS, PEEP, CPAP, and BIPAP

Answer 128

PS- only suppports inhalation with set pressure PEEP- supports exhalation with pressure (keeping alveoli open) CPAP - supports inhalation and exhalation with the same set pressure (augments inhalation, and reduces airway collapse during expiration) BIPAP- adjustable CPAP where you can adjust inspiratory pressure support and expiratory pressure support

Question 129

What is I:E ratio?

Answer 129

it's how much time a pt spends inhaling vs exhaling

Question 130

T/F: the risk of assist control ventilation is respiratory alkalosis

Answer 130

True ## Footnote A/C: vent delivers set Vt and RR but pt can also breathe and if they overbreathe the vent, resp alk

Question 131

At what pH does ethyl violet change to purple? a. 7.5 B. 8.6 C. 10.3 D. 12.1

Answer 131

C. 10.3 ## Footnote who the fuck cares - when its purple - change it

Question 132

The size of co2 absorbent grandules must be between what size? | why?

Answer 132

4-8 mesh ## Footnote it's the size found to provide the best balance between absopritive capacity and work of breathing (absorptive capacity and airflow resistance)

Question 133

Why is it important to turn off your flows between leaving the room?

Answer 133

bc high flows can dry out (dessicate) the soda lime

Question 134

What is the component in soda lime that is strongly alkaline and irritating to the skin and mucous membranes? ## Footnote Whats added to provide hardness and minimize dusst production?

Answer 134

sodium hydroxide - the strong base that neutralizes carbon dioxide (an acid) ## Footnote silica

Question 135

Soda lime can absorb how much CO2 per 100g of absorbent?

Answer 135

16-26L ## Footnote prodigy said 14-23 - so i kept 23 in mind as part of my 23 list apex said specifically 26L so i feel like if i know 23 - i can at least be close to the answer

Question 136

T/F- if you notice your soda lime is exhausted and the pts inspired co2 is climbing, you should increase the pt's minute ventilation ## Footnote *most manufacturers don't recommend changing hte absorbent in the middle of the case

Answer 136

False! - your just ventilating the patient more more ventilation = more co2 into the sodalime thats exhausted already will worsen your problem ## Footnote instead- increase the FGF 1-2x the patients minute ventilation -this converts the circle system into a semi-open one - this shouldp revent rebreathing and the inspired co2 should go down

Question 137

What % of soda lime granules contain water

Answer 137

13-20%

Question 138

T/F- all halogenated anesthetics react with soda lime to produce carbon monxide

Answer 138

True ## Footnote Des > Iso >>> Sevo (comound A)

Question 139

T/F: to reduce carbon monixide build up, we should use low fresh gas flows

Answer 139

True - high FGF will dry it out faster

Question 140

To reduce the inhalation of compound A (interraction b/t sevo and dessicated soda lime) what should your minimum FGF be for: -up to 2 MAC hours -after 2 MAC hours

Answer 140

1-2L/min for up to 2 MAC hours increase to > 2LPM after 2 MAC hours

Question 141

Why is potassium hydroxide not used?

Answer 141

bc it dessicates faster, producing higher levels of carbon monixide and compound A

Question 142

Soda lime equation

Answer 142

1. Co2 + H20 = H2Co3 2. HCO3 + 2NAOH = Na2CO3 + water + heat 3. NaCO3 + Ca(OH)2 = CaOH3 + 2NAOH ## Footnote carbon dioxide exhaled from pt mixes with water on granules and produces **carbonic acid** 2. Carbonic acid combines with *sodium hydroxide* to produce sodium carbonate + water + heat 3. sodium carbonate combines with calcium hydroxide to produce **calcium carbonate and sodium hydroxide ** just remember on each side theres a carbonate (acid) + a hydroxide (base) and each next step starts with the product of the following

Question 143

What is Amsorb? | Benifits? ## Footnote Disadvantages?

Answer 143

Calcium hydroxixde -weaker base | no CO and no compound A ## Footnote high cost and low absorptive capcity

Question 144

Why was baralyme removed from the market?

Answer 144

increased risk of breathing circuit fires when combined with sevoflurane

Question 145

T/F: exhausted sodalime may revert to a colorless stae wehn the anesthesia machine is not in use

Answer 145

True ## Footnote doesn't mean it's regenerated - the color will return quickly to puprle in the presence of co2

Question 146

T/F; if your machine has a double chamber absorber, you must replace both canisters at the same time

Answer 146

True

Question 147

When compared to soda lime, what factor is increased with the use of calcium hydroxide soda lime? A. Carbon monixide B. Frequency of replacement C. CO2 absorption capacity D. Fire risk

Answer 147

B. frequency of repalcement ## Footnote it produces less CO has less absoprtion capcity and fire risk is with baralyme and sevo

Question 148

While a patient is ventilating spontaneously with an ETT, you notice that a fresh gas flow of 10L/min is required to fill the breathing bag and determine that the scavenger is malfunctioning. Which statement must be true? A. The negative pressure reilief valve has failed B. The positive pressure relief valve has failed C. There is an open scavenging system D. There is a passive scavenging system

Answer 148

A. The negative pressure relief valve has failed

Question 149

What are the five compontents of the scavenger system?

Answer 149

1. Gas collection assembly 2. Transfer tubing 3. Interface (open or closed) 4. gas disposal tubing 5. gas disposal system

Question 150

What determines the amount of gas that wremains in the circuit and the amount that is released to the scavenger during: Spontaneous ventilation vs Mechanical ventilation

Answer 150

Spontaneous ventilation - APL valve Mechanical ventilation - the ventilator spill valve

Question 151

Difference between active and passive scavenger systems ## Footnote vs open an dclosed

Answer 151

active - uses suction to remove waste gas passive - relys on the positive pressure of the FGF in the system to push the gas out ## Footnote open- the interface communicates with the operating room envionrment [canister with the ball float] closed- the interface does not communicate with the OR enivonrment (bag)

Question 152

Another name for the ventilator spill valve and what does it do

Answer 152

ventiiator relief valve - diverts excess gas inside pts breathing circuit to the scavenger (if pt is being mechanically ventilated) | if breathing spontaneously, APL valve does this

Question 153

What part of the scavenger contains a resovior for waste gas?

Answer 153

the scavenging interface

Question 154

b/t open and closed systems- which ones has to be only active and which oen can be active or passive

Answer 154

active only = open -open systems are open to the room air, suction (active) system are required in order to keep the waste gas in the system and not leak out to the atomosphere and anesthetize everyone closed systems can be active or passive

Question 155

which type of system is safer for the patient- an open scavenging system or a closed?

Answer 155

open- bc in the event that the scavenger gets blocked, excess pressure can be released out of the system and itno the enviornment instead of causing barotrauma to the patient ## Footnote the closed ssytem relys on pressure valves which could be faulty

Question 156

Which type of scavenger has pressure relief valves in the interface to protect the patient agaisnt extremes of pressure ? ## Footnote when would each be engaged?

Answer 156

Closed systems ## Footnote Positive pressure relief valve - prevents barotrauma in the event of scavenger obstruction negative pressure relief valve (active closed system only) - prevents against excessive suction , which van expose the breathing system to negative pressure leading to hypoxia and NPPE

Question 157

what type of scavenging interface requires a negative pressure relief valve

Answer 157

closed, active ## Footnote so just think negatie pressure would occur from too much suction- so it has to be an active system and whether it's open or closed -- open systems are open to the enviornment to prevent negative pressure - so it has to be a closed system

Question 158

t/f- open systems can be active or passive

Answer 158

false- closed ## Footnote open systems ahve tohave suction (active)

Question 159

t/f- passive systems require a negative pressure relief valve in the scavenging interface

Answer 159

false ## Footnote passive means no suction no suction = no negaitve pressure that can b created in the system

Question 160

Waste gas from the scavenger can go 1 of 2 places ....

Answer 160

1. waste gas receptacle 2. released into the atmoshphere

Question 161

max exposure: halogenated agents alone nitrous oxide alone when they are used together? | who makes these guidelines?

Answer 161

halogenated agents

Question 162

t/f- an opening scavenging system does not require postive or negative pressure relief valves

Answer 162

True ## Footnote it's open to the enviornment so: too much suction entrains room air into the scavenger too little suction vents scavenged gas into the OR

Question 163

T/F- if a passive scavening system is used (not connected to suction) - it MUST have a postive pressure relief valve

Answer 163

true ## Footnote doesn need a negative pressure valve tho bc no suction

Question 164

which component scavenger system determines if it's an open or closed system

Answer 164

the interface

Question 165

which valves must be present on a closed interface- active scavenger

Answer 165

positive AND negative (passive closed jsut neds negative)

Question 166

What is the MOST common cause of low circuit pressure? A. leak in corrugated tubing B. circuit disconnect C. incompetent ventilator relief valve D. improper fitting of co2 absorbent ## Footnote 2nd most common?

Answer 166

B. circuit disconnect ## Footnote 2nd most common = leak around the co2 absorbent

Question 167

4 things that can alert you to a circuit disconnect:

Answer 167

loss of pressure, volume, etco2 and your observation (no chest rise ,ect)

Question 168

How should you approach a question that talks about what will detect a circuit disconnect first ? things to consider...

Answer 168

1. will the montior alert you in real-time - or is there a delay (anything that eis electronic will have a delay and a longer response time) 2. if all the monitors have some degree of delay- which one is the shortest ?

Question 169

What should you do if the breathing circuit doesn't hold pressure in the middle of a cprocedure?

Answer 169

grab an ambu and ventilate with the aux o2 , call for extra hands, convert to TIVA

Question 170

During a general anethetic with ETT, the high peak pressure alarm sounds ; you switch the vent mode to bag mode and the peak pressure returns to baseline . What is the MOST likely explanation for the rise in PIP? A. failed positive pressure relief valve on the scavenger B. kinked ett C. bronchospasm D. ventilator spill valve malfunctioned | what can you look at before switching?

Answer 170

D. ventilator spill valve malfunctioned | plateu pressure - should be similar to PIP ## Footnote relief valve on the scavenger would affect both ventilator and spontaneous pt

Question 171

What is the function of the spill valve ## Footnote what would happen if it malfunctions

Answer 171

it vents excess fresh gas from the flowmeter to the scavenger | flowmeter or pneumatic bellows? ## Footnote the fresh gas would have no where to go and a high circuit pressure could result

Question 172

The transfer tubing joins which components of the scavenger (select 2) - scavenger interface - gas disposal assembly - APL valve - Gas disposal assembly tubing

Answer 172

APL valve > scavenger interface ## Footnote the gas disposal assembly tubing connects the scavenging interface othe gas disposal assembly

Question 173

What is the MIMIMUM amount of pressure when performing a high-pressure leak test on the anesthesia machine

Answer 173

30cm h20

Question 174

What is hte max flow rate delivered by the o2 flush valve?

Answer 174

75LPM ## Footnote 35-75LPM 50 Psi

Question 175

Which of the following components creates the GREATEST resistance to airflow? A. 90 degree elbow B. Unidirectional valve C. Endotracheal tube D. CO@ absorber

Answer 175

C. ETT

Question 176

Which of the following actions reduce compound A production (Select 2) - addition of Ca(OH)2 - removal of NaOH - addition of KOH - removal of CaCl2

Answer 176

addition of Ca(OH)2 & removal of NaOH ## Footnote NaOH and KOH are strong bases that act to facilitate the reaction process.