Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

APEX > Unit 6 - Anesthesia Machine > Flashcards

Unit 6 - Anesthesia Machine Flashcards

1
Q

How does the vaporizer minimize the effect of cooling on vapor pressure and vaporizer output?

A

temperature compensating valve adjusts ratio of vaporizing chamber flow to bypass flow and guarantees a constant vaporizer output over a wide range of temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does the vaporizer minimize the effect of cooling on vapor pressure and vaporizer output?

A

temperature compensating valve adjusts ratio of vaporizing chamber flow to bypass flow and guarantees a constant vaporizer output over a wide range of temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why will a febrile 70 kg adult become hypoxic with an O2 flow at 250 mL/min in a closed circuit system?

A

VO2 for avg adult is 250 mL/min
conditions like sepsis, fever, thyrotoxicosis increase VO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

2 immediate actions if O2 pipeline supply fails

A
  1. turn on O2 cylinder
  2. disconnect pipeline O2 supply
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What 2 functions does drive gas on a pneumatic ventilator serve?

A
  1. compresses bellows
  2. opens and closes spill valve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

position of ventilator spill valve during inspiration

A

closed

ensures that Vt goes to the patient and not to scavenger

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

minimum expiratory pressure needed to open ventilator spill valve

A

3 cm H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

2 complications of overuse of O2 flush valve

A

barotrauma
awareness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

where does the high pressure system begin and end

A

begins at the cylinder, ends at cylinder regulators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where does the intermediate pressure system begin and end

A

begins at pipeline, ends at flowmeter valves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

components of high pressure system

A
  • hanger yoke
  • yoke block with check valves
  • cylinder pressure gauge
  • cylinder pressure regulators
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

components of intermediate pressure system

A
  • pipeline inlets
  • pressure gauges
  • O2 pressure failure device
  • O2 second stage regulator
  • O2 flush valve
  • ventilator power inlet
  • flowmeter valves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

where does low pressure system begin and end

A

begins at flowmeter tubes, ends at common gas outlet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

components of low pressure system

A
  • flowmeter tubes (Thorpe tubes)
  • vaporizers
  • check valve, common gas outlet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does the low-pressure leak test assess

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how is low pressure leak test performed

A

by attaching a bulb to the CGO and creating negative pressure (-65 cm H2O)

If bulb reinflates within 10 seconds = fail, leak in system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

when is the low pressure leak test performed

A

before 1st case of day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

how to perform high-pressure leak test

A

Close APL, pressurizing circuit to 30 cm H2O

change in pressure reading = fail, leak

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what does a high pressure leak test check in a machine with vs. without a check valve

A
  • Machine with check valve: tests circuit & low-pressure system up to the check valve (does NOT assess for leak between check valve and rest of low-pressure system)
  • Machine without check valve: test assesses circuit and entire low-pressure system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

where is a check valve usually located

A

usually downstream from vaporizer, upstream from O2 flush

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

when is high pressure leak test performed

A

before the first case of the day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is the SPDD model

A

Nomenclature describes location of each gas handling component

Supply, Processing, Delivery, Disposal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is S in SPDD model & where is it located

A
  • Supply
  • How the gases enter the anesthesia machine
  • Location: pipeline to back of anesthesia machine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what is P in SPDD model and where is it located

A
  • processing
  • How the anesthesia machine prepares gases before delivery to patient
  • Location: inside machine up to common gas outlet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what is the first D in SPDD model and where is it located

A
  • delivery
  • How the prepared gases are brought to the patient
  • Location: breathing circuit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what is the 2nd D in SPDD model and where is it located

A
  • disposal
  • How the gases are removed from the breathing circuit
  • Location: scavenging system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

5 tasks of O2

A
  1. O2 pressure failure alarm
  2. O2 presure failure devices (failsafe)
  3. O2 flowmeter
  4. O2 flush valve
  5. ventilator drive gas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what is the purpose of PISS

A

pin index safety system

Prevents inadvertent misconnections of gas cylinders

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

what may allow PISS to be bypassed

A

Presence of >1 washer between hanger yoke assembly and stem of tank

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

pin configuration of O2, air, and N2O

A

O2 = 2,5
air = 1,5
N2O = 3,5

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

what ensures that gas is preferentially pulled from pipeline if a cylinder is left open

A

O2 cylinder pressure 1,900 psi drops to ~45 psi upon entry into intermediate system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what is DISS and what is its purpose

A

diameter index safety system

Prevents inadvertent misconnections of gas hose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is DISS and what is its purpose

A

diameter index safety system

Prevents inadvertent misconnections of gas hose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is the only way to determine cylinder content

A

the LABEL, not the color

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

why should O2 cylinder on the back of the machine be OFF when not in use

A

If you lose pipeline pressure and O2 cylinder is left open, you will use up O2 supply before the failsafe alarm sounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

WHO tank colors

A

air = black and white
O2 = white
N2O = blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

how many L in O2 tank

A

660 L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

O2 tank psi

A

1900

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

which is a liquid in the container: O2, air, N2O

A

N2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

max L in air cylinder

A

625 L

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

max psi of air cylinder

A

1900

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

max L in N2O cylinder

A

1590

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

max psi of N2O cylinder

A

745

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

weight of a N2O container full vs empty

A

full = 20.7 lbs
empty = 14.1 lb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

why does O2 exist as a gas in the tank

A

bc its critical temperature is below room temperature (-119 deg C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

what physics law is used to calculate contents of O2 container

A

Boyle’s

pressure inside cylinder inversely r/t volume at a constant temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

calculation to determine how much O2 is in cylinder

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

calculation to determine how long O2 tank will alst

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

why is N2O a liquid inside the tank

A

because N2O liquefies under pressure (critical temp is 36.5 C, above room temp of 20 C)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

when does N2O psi decrease

A

only when all liquid is consumed

at this point, tank is more than ¾ empty - approximately 136 L (at 400

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

when does N2O psi decrease

A

only when all liquid is consumed

at this point, tank is more than ¾ empty - approximately 136 L (at 400

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

what is the only reliable way to determine volume of N2O remaining in tank

A

weigh it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

is CO2 a liquid or gas in container

A

liquid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

max volume & service pressure of CO2 cylinder

A
  • Max volume = 1590 L
  • Service pressure = 893 psi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Most delicate part of cylinder

A

cylinder valve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

what should be inserted if you dont have a replacement cylinder

A

yoke plug
if the check valve fails and there’s no plug, gas that should be going to patient will exit machine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

what does an MRI-safe cylinder look like

A

silver, top is the color of the gas it contains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

why should a cylinder always be opened slowly

A

recompression of gas as it travels through outlet can produce significant heat

dust or debris between tank and yoke can serve as fuel (very rare)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

how to fix hissing sound from a cylinder leak

A
  • 1st tighten connection
  • If that doesn’t work, replace washer between cylinder and hanger yoke assembly
  • If that doesn’t work, use a different cylinder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Fire triad

A

oxidizer, fuel, igniter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

what increases risk of fire or explosion with O2 and N2O cylinders

A
  • Temperatures > 130 F or 57 C increases risk of fire or explosion
  • Oiling the cylinder increases risk by combining O2 or N2O with oil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

safety feature on cylinders in case of fire

A

If there’s a fire, a safety release device opens

allows cylinder to slowly empty contents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Wood’s metal:

A

bismuth, lead, tin, and cadmium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

what is “cracking” a cylinder

A

slowly opening the cylinder to flush the valve outlet clean of dust & debris

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

non-magnetic metal

A

aluminum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Sets standards for required components of anesthesia machine

A

American Society for Testing and Materials (ASTM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Created the 1993 Anesthesia Machine Pre-Use Checkout Procedures

A

Food and Drug Administration (FDA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Sets standards for acceptable occupational exposure to volatiles anesthetics

A

Occupational Safety and Health Administration (OSHA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Sets the standards for compressed gas cylinders

A

United States Department of Transportation (DOT)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

how are cylinders tested for leaks by DOT

A

subjected to 1.66 times its service pressure (ex. 1900 psi tested to 3154 psi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

how often should cylinder safety check be performed per DOT

A

Must be tested every 5 years (10 years with special permit indicated by 5-point star on label)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

what’s required on the cylinder label

A
  • Government agency (DOT)
  • Type of metal used to construct cylinder
  • Maximum filling pressure (psi)
  • Serial number
  • Manufacturer
  • Owner
  • Date of last inspection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

Main purpose of O2 pressure failure device

A

monitor for/against low O2 pressure in machine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

what does O2 pressure failure device alert

A

depleted O2 tank, drop in pipeline pressure, or disconnected O2 hose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

2 components of O2 pressure failure device

A
  1. threshold alarm
  2. pneumatic device
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

when does the threshold alarm sound

A

when O2 pipeline < 28-30 psi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

purpose of pneumatic device in O2 pressure failure device

A

↓ or stops flow of N2O when pressure in O2 < 20 psi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

only gas that passes directly from its source to its flow valve at the flowmeter

A

oxygen

All other gases must encounter fail-safe valve before entering flowmeter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

all or nothing response in GE Datex-Ohmeda O2 failsafe device

A

O2 pressure < 20 psi will completely stop the flow of nitrous oxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

O2 failure protection device in Drager machine

A
  • Decreased pipeline pressure = proportionate decrease in N2O flow
  • The flow of nitrous oxide is stopped only when oxygen pressure is extremely low
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

4 ways to tell if oxygen failure pressure safety device is working

A
  1. Turn ON O2 and N2O flow
  2. Make sure the backup oxygen cylinder is closed & then disconnecting the oxygen pipeline
  3. As you remove the O2 source, the N2O flow should stop just before the O2 flow stops
  4. Reintroducing the O2 supply to the anesthesia machine should result in both gases restored to their previous flow rates
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

what is the gas pressure in the high pressure system

A

cylinder pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

what is the gas pressure in the intermediate pressure system

A

pipeline = 50 psi
tank = 45 psi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

3 safety relief devices that prevent a cylinder from exploding when ambient temp increases

A
  1. fusible plug made of Wood’s metal (melts at increased temp)
  2. frangible disk that ruptures under pressure
  3. valve that opens at elevated pressures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

how does oxygen-pipelinen crossover allow a hypoxic mixture

A

failsafe device responds to pressure (not flow)

if there’s pipeline crossover, the pressure of the 2nd gas will produce pressure to defeat failsafe

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

4 ways the proportioning device (hypoxia prevention safety device) might allow delivery of hypoxic mixture

A
  1. O2 pipeline crossover
  2. leaks distal to flowmeter valves
  3. admin of 3rd gas (helium)
  4. defective mcehanic or pneumatic components
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

2 ways pipeline crossover can cause hypoxic mixture

A
  1. O2-pipeline crossover not detected
  2. flowmeter leak (upstream of flowmeters)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

how does an oxygen pressure failure device work

A

shuts off and/or proportionately reduces N2O flow if O2 pressure < 20 psi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

how does an proportioning device work

aka hypoxia prevention safety device

A

prevents you from setting a hypoxic mixture with flow control valves

limits N2O flow to 3x O2 flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

N2O max with functioning proportioning device

A

75%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

components of the link 25 system

GE Datex-Ohmeda

A
  • O2 & N2O flowmeter valves mechanically linked by a chain (mechanical component)
  • Incorporates a second stage regulator for oxygen and nitrous oxide (pneumatic component)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

purpose of link 25 system

GE Datex-Ohmeda

A

If you adjust the flow control valves in such a way that it would create a hypoxic mixture, a gear engages, and oxygen flow is automatically increased

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

how are O2 and N2O connected in Oxygen Ratio Monitor Controller (Drager)

A

pneumatically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

4 times the proportoning device can’t prevent a hypoxic mixture (won’t alarm)

A
  1. Oxygen pipeline crossover
  2. Leaks distal to the flowmeter valves
  3. Administration of a 3rd gas (helium)
  4. Defective mechanic or pneumatic components
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

what is a Thorpe tube

A

traditional flowmeter

Controls and measures the FGF that travels towards the vaporizers and CG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

what allows fresh gas to enter flowmeter

A

opening flowmeter valve (flow control valve)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

2 opposing forces that determine flowmeter float position

A

1) FGF pushes up, 2) gravity pushes down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

4 types of flowmeter floats

A

skirted, plumb bob, nonrotating, ball

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

where is flow measurement taken in the flowmeter

A

at the widest part of the float

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

which flowmeter floats are read at the top vs. middle

A
  • Read at the top: skirted, plumb bob, nonrotating
  • Read in the middle: ball
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

what is the annular space

A

area between float and side wall of the flowmeter

Geometry of annular space affects flow pattern through it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

what aspect of a flowmeter provides a constant gas pressure throughout wide range of flow rates

A

“variable orifice” architecture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

laminar flow is dependent on:

A

gas viscosity

Poiseulle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

laminar flow is dependent on:

A

gas viscosity

Poiseulle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

turbulent flow is dependent on:

A

gas density

Graham’s Law

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

predicts laminar flow

A

Re < 2000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

predicts turbulent flow

A

Re > 4000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

predicts transitional flow

A

Re 2000-4000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

Reynold’s number calcualtion

A

(density * diameter * velocity) / viscosity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

most delicate part of the machine

A

flowmeters (glass)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

what is the safest flowmeter configuration on anesthesia machine

A

o2 flowmeter should always be furthest right

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

how can a leak in the flowmeters cause delivery of a hypoxic mixture

A

a leak will allow oxygen to escape from low pressure system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

why should oxygen flowmeter always be furthest right (closest to manifold outlet)

A

if a leak develops in any other flowmeters, it won’t reduce the FiO2 delivered

if a leak develops inside O2 flowmeter, can still cause hypoxic mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

why should oxygen flowmeter always be furthest right (closest to manifold outlet)

A

if a leak develops in any other flowmeters, it won’t reduce the FiO2 delivered

if a leak develops inside O2 flowmeter, can still cause hypoxic mixture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

how do you calculate FiO2 set at flowmeter

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

max FiO2 delivered with nasal cannula

A

6 L = 44%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

formula for total Vt delivered to patient in machines with fresh gas coupling

A

= Vt set on ventilator + FGF during inspiration - volume lost to compliance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

how is total Vt delivered to patient calculated in machines with fresh gas coupling

A
  1. convert FGF from L/min to mL/min
  2. multiply FGF by I:E ratio
  3. calculate Vt per breath
  4. add volume set on ventilator to FGF during inspiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

what 4 things impact Vt delivered to patient in a machine that couples FGF to Vt

A
  1. any change in FGF
  2. bellows height
  3. RR
  4. I:E ratio
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

how does increased FGF impact Vt, Vm, PIP, and EtCO2 in machines that couple FGF to Vt

A

↑ Vt, Vm, PIP
expect EtCO2 to decrease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

how does decreased FGF impact Vt, Vm, PIP, and EtCO2 in machines that couple FGF to Vt

A

↓ Vt, Vm, PIP
expect EtCO2 to increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

vent changes that increase delivered Vt in machines that couple FGF & Vt

A
  1. decreased RR
  2. increased I:E (ex. 1:2 to 1:1)
  3. increased FGF
  4. increased bellows height
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q

vent changes that decrease delivered Vt in machines that couple FGF & Vt

A
  1. inc. RR
  2. dec I:E ratio (ex. 1:2 to 1:3)
  3. dec FGF
  4. dec bellows height
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

what is compliance

A

a change in volume for a given change in pressure

it is a measure of distensibility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

what is compliance

A

a change in volume for a given change in pressure

it is a measure of distensibility

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

how does positive pressure inside the breathing circuit affect the circuit

A

causes it to expand

This quantity of gas does not reach the patient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

how does positive pressure inside the breathing circuit affect the circuit

A

causes it to expand

This quantity of gas does not reach the patient, and therefore does not

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

volume lost to circuit =

A

circuit compliance * peak pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

what is the splitting ratio

A

when FGF enters vaporizer, it either goes into vaporizing chamber & becomes 100% saturated with anesthetic agent or goes into bypass chamber and does not contact anesthetic agent

130
Q

what determines the splitting ratio

A

setting dial on desired concentration

  • Higher concentration directs more fresh gas through vaporizing chamber
  • Lower concentration directs more fresh gas through bypass chamber
131
Q

what determines the final anesthetic concentration exiting the vaporizer

A

before leaving the vaporizer, the 2 fractions from the splitting ratio mix

132
Q

purpose of baffles & wicks in vaporizer

A

increase surface area & turbulence, ensures fresh gas inside chamber becomes 100% saturated with anesthetic agent

133
Q

what is vapor pressure

A

pressure exerted by a vapor in equilibrium with its liquid phase inside a closed container

↑ temperature = ↑ vapor pressure

134
Q

what is latent heat of vaporization

A

number of calories needed to convert 1g liquid into vapor without causing a change in temperature

135
Q

what does a temperature compensating valve in the vaporizer do

A

adjusts ratio of vaporizing chamber flow to bypass chamber flow

Either a bimetallic strip or expansion element

136
Q

what does a temperature compensating valve in the vaporizer do

A

adjusts ratio of vaporizing chamber flow to bypass chamber flow

Either a bimetallic strip or expansion element

137
Q

Guarantees constant vaporizer output over a wide range of temperatures

A

Temperature compensating valve

138
Q

how does the temp compensating valve affect bypass chamber flow

A
  • Colder= increases vaporizing chamber flow, ↓ VP, ↓ vaporizer output
  • Hotter = increases bypass chamber flow
139
Q

why are most modern vaporizers out of circuit

A

isolated from anesthetic breathing system

Can remove vaporizer from anesthesia machine without compromising integrity of breathing system

140
Q

VP of sevo, des, and iso

A
  • Sevoflurane = 157 mmHg
  • Isoflurane = 238 mmHg
  • Desflurane = 669 mmHg
141
Q

most likely cause of vaporizer leak

A

loose filler cap

142
Q

most common location for leak in low-pressure system

A

Internal leak in the vaporizer

143
Q

Estimated liquid anesthetic usage

A

liquid anesthetic used per hour (mL) = vol% x FGF (L/min) x 3

144
Q

what should you do if the vaporizer is tipped

A

1) drain vaporizer
2) run high FGF through vaporizer for 20-30 min or until all liquid anesthetic is vaporizers

145
Q

when can a vaporizer be used again after a vaporizer is tipped

A

When expired gas analysis no longer detects anesthetic agent, can fill and use on a patient

146
Q

method to eliminate worry of tipping vaporizer

A

Set to transport mode (T)

147
Q

what is the pumping effect

A

can increase concentration of anesthetic leaving vaporizer (vaporizer output)

Can be from anything that causes gas that has already left vaporizer to re-enter vaporizing chamber

148
Q

what generally causes pumping effect

A
  1. PPV
  2. O2 flush valve
149
Q

what eliminates concern of pumping effect

A

Check valve anywhere between vaporizer and CGO

150
Q

what eliminates concern of pumping effect

A

Check valve anywhere between vaporizer and CGO

151
Q

prevents simultaneous administration of different anesthetic gases

A

interlock system

Makes sure FGF only travels through one vaporizer at a time

152
Q

prevents simultaneous administration of different anesthetic gases

A

interlock system

Makes sure FGF only travels through one vaporizer at a time

153
Q

why is a special vaporizer required for des

A
  • significantly less potent than other volatiles & has VP close to atmospheric pressure
  • To achieve the same depth of anesthesia, absolute volume of des that must be vaporized is higher
  • Heating and pressurizing Tec 6 to 39 C and 2 atm solves these issues
154
Q

why can’t a variable bypass vaporizer be used for desflurane

A

would require bypass flow well beyond the limits of the anesthesia machine to dilute des to clinically useful concentration d/t its high VP

155
Q

how does ambient pressure affect Tec 6 vaporizer

A
  • Lower ambient pressure (higher altitude) requires higher setting on dial
  • Higher ambient pressure (hyperbaric O2 tank) requires lower setting on dial
156
Q

calculation for required dial setting of desflurane in different pressures

A
157
Q

which volatile uses an injector vaporizer

A

desflurane

158
Q

method of vaporization for variable bypass vaporizer

A

flow over

159
Q

method of vaporization for injector vaporizer

A

gas/vapor blender

heat creates vapor that is injected into fresh gas

160
Q

method of vaporization for injector vaporizer

A

gas/vapor blender

heat creates vapor that is injected into fresh gas

161
Q

which type of vaporizer compensates for changes in elevation

A

variable bypass

162
Q

where is the oxygen analyzer

A

Resides in inspiratory limb of breathing circuit or component of multigas monitor

163
Q

what does the oxygen analyzer measure

A

monitors oxygen concentration (not pressure)

164
Q

only device downstream of flowmeters that can detect a hypoxic mixture

A

oxygen analyzer

165
Q

what can detect hypoxic mixture caused by leak in O2 flowmeter

A

oxygen analyzer

166
Q

how does the Galvanic Fuel-Cell work

A

Increasing oxygen tension generates a current across two electrodes

167
Q

which is faster - galvanic fuel cell or paramagnetic device

A

paramagnetic

168
Q

how does the paramagnetic device work in the oxygen analyzer

A

increasing oxygen tension creates an increased magnetic attraction

169
Q

which is self-calibrating - galvanic fuel cell or paramagnetic device

A

paramagnetic

170
Q

how can a hypoxic mixture be created in closed-circuit anesthesia

A
  • If consumption increases, but delivery remains constant
  • only O2 analyzer will detect
171
Q

causes of reduced FiO2 during low flow anesthesia in closed circuit

A

(↑ O2 consumption): sepsis, pain, SNS stimulation, thyrotoxicosis, fever, etc.

172
Q

O2 consumption in avg adult

A

250 mL/min

173
Q

only device to detect oxygen-pipeline crossover

A

O2 analyzer

174
Q

what should you assume when oxygen analyzer alarms

A

pipeline crossover has occurred until other causes can be ruled out

175
Q

2 things to do if O2 pipeline supply fails

A

1) turn ON O2 cylinder, 2) disconnect pipeline O2 supply

176
Q

what should you do if the oxygen analyzer alarms and O2 concentration in breathing circuit is not increasing with O2 cylinder on

A

assume machine malfunction and ventilate with Ambu (using different O2 tank or room air)

177
Q

how to conserve tank O2 in event of oxygen pipeline failure

A

using low flows

if using machine with O2 as driving pressure to compress bellows, hand ventilate the patient to conserve O2 (if machine uses air to power ventilator or is piston-driven, can remain on ventilator)

178
Q

provides path for O2 to travel from intermediate pressure system to breathing circuit

A

O2 flush

179
Q

flow and pressure O2 flush button exposes circuit to

A

O2 flow of ~35-75 L/min, O2 pressure of ~50 psi (pipeline pressure)

180
Q

negative effect of using O2 flush during inspiration

A

barotrauma

Ventilator spill valve is closed during inspiration

181
Q

negative effect of using O2 flush during inspiration

A

barotrauma

Ventilator spill valve is closed during inspiration

182
Q

2 Functions of Drive Gas on Pneumatic Ventilator

A
  1. Compresses bellows
  2. Opens & closes ventilator spill valve
183
Q

separate the drive gas circuit from the patient breathing circuit

A

bellows

184
Q

2 risks associated with pressing the O2 flush valve

A

barotrauma and awareness

185
Q

how does drive gas compress bellows on pneumatic ventilator

A
  • inspiration: drive gas flow increases pressure in ventilator chamber & creates a pressure gradient that pushes fresh gas in pts lungs
  • expiration: flow stops and pressure gradient reverses (pressure in chest > inside bellows), pt can exhale Vt
186
Q

function of spill valve in pneumatic ventilator

A
  • During inspiration, drive gas closes spill valve & ensures that Vt goes to pt and not scavenging
  • During exhalation, flow of gas drive stops
187
Q

function of spill valve in pneumatic ventilator

A
  • During inspiration, drive gas closes spill valve & ensures that Vt goes to pt and not scavenging
  • During exhalation, flow of gas drive stops
188
Q

why is intrinsic PEEP possible in pneumatic ventilators

A

exhaled Vt first refills bellows & after circuit pressure > ~3 cm H2O, spill valve opens and excess gas exits scavenger

189
Q

amount of air going to bellows =

A

Vt + flowmeter flow during exporation

190
Q

3 things that happen during inspiration in pneumatic ventilators

A
  1. drive gas compresses bellows
  2. drive gas closes spill valve
  3. fresh gas from ventilator geos to patient
191
Q

3 things that happen during expiration in pneumatic ventilators

A
  1. expired gas refills bellows
  2. bellows fill completely
  3. when circuit pressure > 2-4 cm H2O expired gas is directed through spill valve to scavenger
192
Q

2 methods that reduce barotrauma with O2 flush valve

A

1.Fresh gas decoupling
2.Inspiratory pressure limiter

193
Q

what is fresh gas coupling

A

what is set on ventilator is actually what’s delivered to patient

Vt delivered by ventilator is isolated from flowmeters and O2 flush valve

194
Q

what is the Inspiratory pressure limiter

A

can limit breathing circuit pressure during inspiration

when breathing circuit pressure rises above setpoint, excess gas is vented to scavenger (think of as APL valve for ventilator)

195
Q

how can O2 flush cause awareness

A

Excessive use adds dilutes partial pressure of volatile, may lead to awareness (gas from flush doesn’t pass through vaporizers & adds gas to circuit that doesn’t have volatile)

196
Q

gas inside bellows =

A

exhaled Vt + FGF during expiration

197
Q

consequences of leak in bellows

A
  • Drive gas mixes with patient circuit
  • Increased inspired FiO2 (if drive gas is oxygen)
  • Decreased inspired FiO2 (if drive gas is air or air-oxygen mixture)
  • Barotrauma (may transmit high gas pressure to breathing circuit)
  • Dilution of volatile concentration (can lead to awareness)
198
Q

movement of ascending bellows

A

rise during expiration

199
Q

movement of descending bellows

A

falls with inspiration

200
Q

classic problem with descending bellows

A

may continue to rise & fall with circuit disconnect

201
Q

which type of bellows is considered safer

A

ascending

will only partially fill if there’s a leak

202
Q

which type of bellows is considered safer

A

ascending

will only partially fill if there’s a leak

203
Q

mechanism of piston ventilator

A

Utilize electric motor to compress piston & generate positive pressure

Will not consume tank O2 in event of pipeline failure

204
Q

mechanism of piston ventilator

A

Utilize electric motor to compress piston & generate positive pressure

Will not consume tank O2 in event of pipeline failure

205
Q

what do piston ventilators require for bellow compresion during MV

A

O2

206
Q

what is fresh gas decoupling in a piston ventilator

A

Deliver constant Vt regardless of changes to FGF, RR, I:E

207
Q

function of positive pressure relief valve in piston ventilator

A

opens at 75 +/- 5 cm H2O

prevents excessive pressure in circuit

208
Q

function of Negative pressure relief valve in piston ventilator

A

opens at -8 cm H2O

entrains room air, protects patient against negative end-expiratory pre

209
Q

function of Negative pressure relief valve in piston ventilator

A

opens at -8 cm H2O

entrains room air, protects patient against negative end-expiratory pre

210
Q

do piston ventilators add PEEP like gas-driven bellows

A

Nope

211
Q

why do gas-driven bellows add PEEP

A

automatically add 2-3 cm H2O d/t design of ventilator spill valve

212
Q

movement of breathing bag during mechanical ventilation with piston ventilator

A

Bag inflates during inspiration, deflates during expiration

Bag won’t move when pt initiates spontaneous breaths while on ventilator

213
Q

movement of breathing bag during mechanical ventilation with piston entilator

A

Bag inflates during inspiration, deflates during expiration

Bag won’t move when pt initiates spontaneous breaths while on ventilator

214
Q

Delivers a preset Vt over predetermined time

A

volume controlled ventilation

215
Q

Delivers a preset inspiratory pressure over predetermined time

A

pressure controlled ventilation

216
Q

what causes PIP to increase in VCV

A

↑ airway resistance or ↓ lung compliance

217
Q

variable factors in VCV

A

Inspiratory pressure varies with compliance

218
Q

variable factors with PCV

A

Vt and inspiratory flow vary with compliance

219
Q

variable factors with PCV

A

Vt and inspiratory flow vary with compliance

220
Q

fixed settings in VCV

A

Vt, inspiratory flow rate, inspiratory time

221
Q

fixed settings in PCV

A

PIP, inspiratory time

222
Q

variable settings in PCV

A

Vt, inspiratory flow

223
Q

inspiratory flow in VCV

A

held constant during inspiration

224
Q

inspiratory flow in PCV

A

typically uses decelerating pattern – begins high to achieve inflation pressure, then slows to maintain constant inflation pressure

225
Q

advantages of PCV

A
  • Delivers larger Vt for given inspiratory airway pressure
  • Inspiratory flow pattern may improve gas exchange
  • Reduces risk of ventilator-assoc. lung injury (VALI)
  • Useful if pt has low compliance or to compensate for leaks
226
Q

PCV Disadvantages

A
  • Increased airway resistance or decreased lung compliance = ↓ Vt
  • Extra attention to conditions that alter compliance or resistance (cause Vt to change)
227
Q

things that can cause decreased Vt with PCV

A

decreased compliance (pneumoperitoneum, Trendelenburg), increased resistance (bronchospasm, kinked ETT)

228
Q

things that cause increased Vt with PCV

A

increased compliance (pneumoperitoneum released, Tburg to supine), decreased resistance (bronchodilators, suctioning airway secretions)

229
Q

3 situations when PCV is better than VCV

A
  • Patient has low compliance: pregnancy, obesity, laparoscopy, ARDS
  • High PIP would be dangerous: LMA, neonate, emphysema
  • Need to compensate for leak: LMA, uncuffed ETT
230
Q

what does a negative deflection just before breath indicates

A

patient-triggered breath

231
Q

which breath is assisted and which is spontaneous

A

green = assisted
blue = spontaneous

232
Q

controlled mandatory ventilation

A

Machine initiated breath delivers preset Vt & RR on fixed schedule

233
Q

why is CMV assoc. with risk of patient-ventilator asynchrony

A

Doesn’t compensate for pt initiated breaths

234
Q

best vent mode for apneic patients

A

CMV

235
Q

assist control mode

A
  • Machine initiated breath delivers preset Vt & RR
  • Spontaneous breaths receive full preset Vt
236
Q

risk of overbreathing with assist control

A

hyperventilation & respiratory alkalosis

237
Q

risk of overbreathing with assist control

A

hyperventilation & respiratory alkalosis

238
Q

vent mode that allows the patient to breath spontaneously between machine initiated breaths

A

SIMV

239
Q

how does SIMV guarantee a set minute ventilation

A

the more the patient works, the less assistance the ventilator provides and vice versa

240
Q

PCV-VG

A

Benefits of pressure control ventilation, but also guarantees a predetermined Vt while applying the minimum pressure required to achieve it

241
Q

PSVPro

A
  • “Pro” = protect
  • Spontaneously breathing patient receives PSV
  • If pt becomes apneic, ventilator converts to pressure-control ventilation (PCV)
  • When pt resumes spontaneous ventilation, ventilator goes back to PSV
242
Q

2 benefits of CPAP

A

augments the pt’s spontaneous breath, reduces airway collapse during expiration

243
Q

difference in CPAP and PSV

A

PSV only applies pressure to the circuit when the patient initiates a breath (there is nothing during expiration)

244
Q

P1 and P2 in BiPAP

P = pressure

A
  • P1 = inspiratory positive airway pressure (think pressure support for a spontaneous breath)
  • P2 = Expiratory positive airway pressure (think CPAP during exhalation)
245
Q

when is BiPAP useful

A

patient with COPD or when CPAP isn’t quite enough

246
Q

what is APRV

Airway Pressure Release Ventilation

A
  • Like BiPAP, but there is a high level of CPAP throughout most of the respiratory cycle
  • The high level of pressure is released at preset intervals to facilitate exhalation
247
Q

patient requirements for IRV

A

Requires a paralyzed and sedated patient (no spontaneous ventilation)

248
Q

when is IRV useful

A

patient with a small FRC or in the patient with ARDS

249
Q

risk with IRV (inverse ratio ventilation)

A

dynamic hyperinflation (auto-peep or breath stacking)

250
Q

what is IRV

A

IRV reverses typical I:E ratio by allocating more time to inspiration

251
Q

gas transport in conventional modes of ventilation

A

gas transport occurs by convection (large airways) and convection + molecular diffusion (small airways and alveoli)

252
Q

what is HFV

High Frequency Ventilation

A

HFV delivers a Vt below anatomic dead space in conjunction with a very high respiratory rate

253
Q

how does gas transport occur in HFV

A

ombination of molecular diffusion, coaxial flow, and high velocity flow

254
Q

how do carbon dioxide absorbents work

A

remove exhaled carbon dioxide from the breathing circuit

a base neutralizes an acid

255
Q

what should you do with exhausted soda lime in the middle of a surgical procedure

A

increase FGF to convert circle system into semi-open configuration

256
Q

best balance of mesh size in soda lime

A

4-8 mesh granules used

* Small granule = high surface area with high resistance
* Large granule

257
Q

best balance of mesh size in soda lime

A

4-8 mesh granules used

* Small granule = high surface area with high resistance
* Large granule

258
Q

how big is each granule of mesh in soda lime

A

Each granule is between 1/8 and 1/4 inch diameter  will pass through mesh with 4-8 holes per square inch

This size provides the best combination of absorptive capacity and airflow resistance

259
Q

2 Major Problems with Soda Lime

A

1) exhausted absorbent (no longer able to neutralize CO2)
2) desiccated absorbent (too dry)

260
Q

what makes soda lime a strong base

A

Sodium hydroxide

261
Q

when does soda lime turn blue-purple

A

As pH falls < 10.3, indicator dye such as ethyl violet will change to blue-purple

As CO2 consumes basic substrates, pH of absorbent ↓

262
Q

when does soda lime turn blue-purple

A

As pH falls < 10.3, indicator dye such as ethyl violet will change to blue-purple

As CO2 consumes basic substrates, pH of absorbent ↓

263
Q

Best indicator of expired soda lime:

A

presence of inspired CO2 in breathing circuit

264
Q

when can ethyl violet in soda lime revert to a colorless state

A

when machine not in use but quickly returns to blue-purple in presence of CO2 if exhausted

265
Q

___ is required to facilitate reaction of CO2 with CO2 absorbent

A

water

266
Q

when is absorbent dessicated

A

when its devoid of water

267
Q

water content of absorbent granules

A

Granules hydrated to 13-20% by weight

268
Q

adverse effect of desiccated absorbent

A

Increases production of carbon monoxide des > iso&raquo_space;> sevo) & compound A with sevo

269
Q

most unstable volatile in soda lime

A

sevo

270
Q

methods to ↓ Risk Carbon Monoxide & Compound A

A
  • Utilize low FGF to preserve water content
  • Turn off FGF in between cases
  • Change all absorbent at one time (not a single canister in dual canister set up)
  • Change canisters when ethyl violet signifies exhaustion
  • Change canisters if unsure about level of hydration (Ex. FGF left on overnight)
271
Q

why is aborbent strongly irritating to skin and mucous membranes

A

Sodium hydroxide is strongly alkaline

272
Q

purpose of silica in absorbent

A

provides hardness & minimizes dust production

273
Q

absorbent that doesn’t contain strong bases

A

Calcium Hydroxide Lime (Amsorb Plus)

no NaOH, KOH

274
Q

absorbent that doesn’t contain strong bases

A

Calcium Hydroxide Lime (Amsorb Plus)

no NaOH, KOH

275
Q

additive in calcium hydroxide lime that acts as a humectant

A

CaCl

276
Q

purpose of CaCl additive in calcium hydroxide lime

A

humectant (opposite of dessicant)

keeps absorbent moist

277
Q

purpose of CaCl additive in calcium hydroxide lime

A

humectant (opposite of dessicant)

keeps absorbent moist

278
Q

added to Calcium Hydroxide Lime to increase hardiness

A

calcium sulfate & polyvinylpyrrolidone

279
Q

Amsorb Plus Benefits

A
  • No carbon monoxide production
  • Very little or no compound A production
  • Lower risk of fire compared to soda lime
280
Q

Amsorb Plus Drawbacks

A
  • Soda lime can absorb 26 L CO2 per 100 g absorbent; calcium hydroxide can only absorb 20.6 L of CO2 per 100 g absorbent
  • Absorptive capacity is less than soda lime (requires more frequent replacement)
  • More expensive
281
Q

function of scavenger system

A

remove excess gas from anesthesia circuit & minimize environmental exposure to waste anesthetic gas

282
Q

how is constant pressure maintained in circuit with scavenging system

A

must only remove an amount of gas equal to FGF minus volume of gas lost due to patient’s O2 consumption

283
Q

most critical component of scavenging system

A

interface

removal of too much gas could create negative pressure in circuit, removal of too little increases risk of barotrauma

284
Q

how is FGF to scavenger controlled

what determines amount of gas remaining in circuit & amount released

A
  • Spontaneous ventilation determined by APL valve
  • Mechanical ventilation determined by ventilator spill valve
285
Q

how is FGF to scavenger controlled

what determines amount of gas remaining in circuit & amount released

A
  • Spontaneous ventilation determined by APL valve
  • Mechanical ventilation determined by ventilator spill valve
286
Q

5 Components of scavenging system

A
  1. Gas Collecting Assembly
  2. Transfer Tubing
  3. Scavenging interface
    a. Open System
    b. Closed System
  4. Gas Disposal Assembly Tubing
  5. Gas Disposal Assembly
287
Q

Collects waste gas from breathing circuit

A

Gas Collecting Assembly

288
Q

location of Gas Collecting Assembly

A

at APL & ventilator spill valve

289
Q

directs collected gas to interface (connects APL to scavenging interface)

A

Transfer tubing

290
Q

what type of scavenging can only be used with active system

A

open system interface

291
Q

benefits of open system scavenging interface

A

Removes risk barotrauma or removal of FGF from circuit

292
Q

risk of too much suction with open scavenging interface

A

entrains air in scavenger

293
Q

how do open vs closed scavenging interfaces connect to atmosphere

A
  • open = open to atmosphere
  • closed = communicates to atmosphere with pressure valves
294
Q

required for closed system scavenging interface with passive system

A

positive pressure relief

295
Q

required for closed system scavenging interface with active system

A

positive and negative pressure relief

296
Q

required for closed system scavenging interface with active system

A

positive and negative pressure relief

297
Q

required for closed system scavenging interface with active system

A

positive and negative pressure relief

298
Q

when does positive pressure relief valve pop off in closed interface

A

+5 cm H2O

299
Q

when does negative pressure relief valve entrain room air in closed interface active system

A

-0.5 cm H2O

300
Q

Removes gas from scavenging interface

A

Gas Disposal Assembly Tubing

301
Q

Directs gas from scavenger to hospital suction and ultimately atmosphere

A

Gas Disposal Assembly

302
Q

how does passive scavenging disposal remove gas

A

relies on positive pressure of fresh gas leaving interface

303
Q

how does active scavenging disposal remove gas

A

suction

304
Q

Most common source of preventable equipment-related complications

A

circuit disconnect

305
Q

Most common site of circuit disconnect

A

Y-piece

2nd most common: CO2 absorbent canister

306
Q

Most common site of circuit disconnect

A

Y-piece

2nd most common: CO2 absorbent canister

307
Q

Most common site of circuit disconnect

A

Y-piece

2nd most common: CO2 absorbent canister

308
Q

Most common site of circuit disconnect

A

Y-piece

2nd most common: CO2 absorbent canister

309
Q

Sources of Low Pressure in Circuit

A
  • Circuit disconnect
  • Leaks in circuit
  • Malfunction of bag/ventilator selector switch
  • Moisture buildup in flow sensors preventing proper function of ventilator
  • Incompetent ventilator spill valve (Vt directed to scavenger)
  • Defective CO2 absorbent canister
  • Leaks around CO2 absorbent (common after granules changed)
310
Q

4 ways to monitor for circuit disconnect

A

pressure, volume, EtCO2, vigilance

311
Q

monitors concentration of O2 in circuit

A

Oxygen analyzer

312
Q

what should you do if unable to ventilate due to low pressure

A

ventilate with bag-valve-mask and O2 tank while providing TIVA

313
Q

Consequences of ↑ circuit pressure

A
  • subcutaneous emphysema
  • ↓ venous return
  • ↓ CO
  • CV collapse
  • hypotension
  • PTX
  • barotrauma
  • high PEEP
314
Q

what should you do first if PIP increases enough to trigger high PIP alarm

A

irst rule out patient related causes (#1 – bronchospasm) and attempt to manually ventilate

315
Q

what should you assume if high PIP and when pt removed from ventilator (APL open) PIP returns to baseline

A

most likely explanation is failed ventilator spill valve

316
Q

what should you assume if high PIP and when pt removed from ventilator (APL open) circuit pressure ↑

A

most likely cause is that scavenger is occluded or positive pressure relief valve failed

317
Q

what should you do if PIPs are increased d/t occluded scavenging or positive relief valve failure

A

remove scavenger tubing from APL or remove pt from breathing circuit and ventilate with Ambu bag/begin TIVA

318
Q

Developed guidelines for max exposure to inhalational anesthetics in the OR

A

OSHA

319
Q

OSHA max exposure to inhalational anesthetics in the OR

A
  • Halogenated agents alone should be < 2 ppm
  • N2O alone should be < 25 ppm
  • Halogenated agents + N2O should be < 0.5 ppm and 25 ppm respectively
320
Q

Determinants of Exposure to Waste Gases

A
  1. Amount of OR ventilation and air turnover
  2. Functional status of anesthesia equipment
  3. Your practice as a CRNA
321
Q

how much negative pressure should be created for a proper negative pressure test

A

-65 cm H2O

APEX (54 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions