Ventilators Flashcards
1
Q
Ventilation eliminates what?
A
CO2
2
Q
What are the 2 major functions of the lung?
A
ventilation
oxygenation
3
Q
The CO2 gas of metabolism enters ______, and the CO2 gas is expelled form the lungs on exhalation.
A
the alveoli of the lungs
4
Q
What is one method to start waking people up?
A
Increase their CO2 to stimulate them to breath
5
Q
How is oxygenation best represented?
A
the partial pressure of O2 in the arterial blood (PaO2)
6
Q
What normally dictates the minute ventilation?
A
quantity of CO2 produced
7
Q
In the absence of dx, high altitude, and pharmacologic intervention, what is the PaCO2 of spontaneous ventilation?
A
40 mmHg
8
Q
The force exerted by the ventilator is measured by what?
A
pressure
9
Q
What 2 things must pressure overcome that impede motion during inspiratoin?
A
compliance
resistance
10
Q
When mechanical ventilation is used, exhlaation is passive or active?
A
passive
11
Q
Compliance and resistance may be regarded as the “load” facing the inspiratory pressure that results in the 2 fundamental varialbes:
A
TV
inspiratory flow
12
Q
WHen inspiratory flow is matched to a desired TV, the inspiratory _____ varies to the given load.
A
pressure
13
Q
When the inspiratory flow is matched to a desired inspiratory pressure, the ___ varies to the given load.
A
TV
14
Q
Cough suppression can cause?
A
retention of secretions in tube
15
Q
What occurs d/t changes in physiologic and mehcanism dead space?
A
V/Q mismatch
16
Q
What are 2 cons to suctioning the tube?
A
it can cuase negative pressure - results in atelectasis and entrainment of Nitrogen that reduces teh fraction of inspired O2
17
Q
___ causes an increase in intrathoracic pressure during inspiration.
A
IPPV
18
Q
What can elevated intrathoracic pressures decrease?
A
blood flow returning to heart, (& CO)
19
Q
PEEP can decrease ____
A
venous return
20
Q
What is an injury r/t pressure of mechanical ventilation?
A
barotrauma
21
Q
What are s/s of barotrauma if a full pneumo does not occur?
A
physiologic and pathologic changes r/t alveolar overstreatching
22
Q
What is injury r/t volume and mechanical ventilatioN?
A
volutrauma
23
Q
What is damage r/t shear stress from the opening and closing of alveoli durign mechanical ventilation called?
A
atelectrauma or shear trauma
24
Q
What causes atelectrauma?
A
pressure and volume related changes
25
What is optimal PEEP usually?
5-15 cmH20
26
What is recommended TV?
6-8 mL/kg
27
What is TV based off of ?
IBW
28
What is a typical I:E ratio?
1:2 or 1:4
29
Inverse Ratio VentilatioN: The objective is to _____ mean airway pressure and minimize _____ pressure with a desired outcome of recruiting collapsed alveoli w/o _____.
increase
peak
overdistention
30
What vent pressure directly corresponds w/ alveolar recruitment, reduction in shunt fraction, and increased oxygenation?
Mean airway pressure
31
What should you keep your peak pressure less than?
40
32
What pushes or drives the gas to the patient in a ventilator?
bellows or piston
33
The desgination of ascenidng or descending bellows was based on bellows movemnt on _____.
exhalation
34
An ascending bellow ___ during exhalation
rises
35
A descending bellow ___ during exhalation
falls
36
In the event of a circuit disconnect or significant leak, what bellow (asending or descending) would not fill or would improperly fill udring exhalation?
ascending
37
What type of bellow could fill whether a circuit disconnect, leak, or normal exhalation was present?
hanging
38
Hanging bellow ventilators must rely on a ____ to detect leaks and inadequate FGF.
separate reservoir bag
39
___ pressure gas typically is used to drive the bellows.
high
40
A hole or perforation in the bellows can subject the patient to driving gas pressures and result in _____.
barotrauma
41
With a piston ventilator, what is used to drive or displace the piston within the cylinder to cause gas flow?
electric motor
42
What is believed to be improved with piston vs. bellows d/t precise postion of piston?
TV accuracy
43
A leak occuring at the piston diaphragm could cause a loss of circuit gas to the room with _____ during inspiration.
hypoventilation
44
Piston ventilators use what to monitor for circuit leaks or inadequate FGF?
Fresh gas decoupling w/ a separate reservoir bag
45
What does a turbine ventilator rely on to produce a drive gas pressure?
spinning turbine
46
With turbine ventilators, higher revolutions per minutre are associated with _____, while lower RPMs are associated w/ _____.
higher pressures
lower circuit pressures
47
What ventilator type is associated with circuit dead space reduction, improved gas mixing, and rapid establishment of desired gas concentrations?
Turbine b/c constant flow of turbine
48
What two significant events occur in a normal ventilator breath?
inspiration
exhalation
49
____ describes the event that transitions the ventilator from exhalation to inspiration and from inspiration to exhalation.
cycling behavior
50
A sensor can be used to initiate inspiration on spontaneous patient effort in what vent mode?
pressure support ventilation (PSV)
51
The trigger, an observed parameter to allow inspiration to occur, can be ___, ___, or ____.
pressure
volume
flow values
52
Cycling from inspiration to exhalation can occurs as a result of achieving a _____, ___, ___, or ____.
set volume, pressure, flow, or time
53
Exhalation is typically a ____ event.
passive
54
Pressures in the airway can be manipulated during exhalation by the addition of ____
PEEP
55
A _____ is used in ventilation when the inspiratory flow waveform is controlled around the use of a high-pressure source; the source in this case is typically greater than 5x the airway pressure.
flow generator
56
A _____ is used when the pressure waveform is controleld around the use of a low-pressure source, usually near or moderately higher than the airway pressure.
pressure generator
57
When a ____ source is used, changes in patient compliance and resistanc ehave little effect on the inspiratory flow waveform.
high pressure
58
With a ____ source, changes in compliance and resistance affect the inspiratory flow waveform.
low-pressure
59
Constant flow generator is a ___ pressure ventilator???
high
60
Constant pressure generator is a ___ pressure ventialtor???
low
61
A variable flow generator can provide different flow waveforms such as ___, ___, or ____ flow.
increasing/ascending ramp
Decreasing/descednign ramp
sinusoidal flow
62
What accompanies high pressure ventilation?
hypotension
63
Declining inspiratory flow settings allow time for ____ at the end of ____
gas redistribution
inspiration
64
An accelerating inspiratory flow setting is intended to achieve ventilation while minmizing the effect on _____
intrathoracic pressure
65
The prolongation of the ____ period maximizes the time for venous return.
expiratory
66
What flow setting incorporates:
prolonged exhalation
Rapid inspiration w/ no plateua
accelerating inspiratory flow
67
What flow setting incorporates:
normal flow until lungs are filled
plateua for distribution
Declining inspiratory flow
68
A TV maintained after inspiratory flow ceases, a so-called ___ or _____, provides the opportunity for gas to redistribute within the lung.
plateau
inspiratory hold
69
Inspiratory hold settings on ventilators improve what?
gas exchange
70
IRV is a means of increasing mean airway pressures w/o increasing what?
peak airway pressure
71
IRV is defined as an I:E ratio greater than ___.
1:1
72
What are two concerns with IRV?
breath stacking
auto-peep
73
At the end of each breath, the pressure is commonly maintained at an end-expiratory pressure of ___ above 0 b/c of the weight of valves and bellows, although some ventilators provide direct control to set additional PEEP.
2-4 cmH2O
74
Dr. White's recommendation is that if you use a PEEP >___, you should transport to ICU with PEEP valve.
10
75
PEEP can affect what?
venous return to the heart
76
The introduction of a constrictive orifice during exhalation can benefit some patients with advanced lung disease d/t the fact that the expiratory retard will ___ expiratory flow rate and allow more ____ flow to better empty the lungs.
decrease
laminar
77
When might the introduction of expiratory retard/constrictive orifices be beneficial?
with severe bronchoconstriction (status asthmaticus)
78
Why is expiratory retard rarely used?
can cause breath stackign and potentially dangerous high pressure
79
In combination w/ O2, anesthetic gas typically flows continuosly from where?
common gas outlet
80
T/F: FGF commonly contributes to actual delivered TV if it continues to flow into the breathing circuit during the inspiratory phase.
True - however newer vents offer fresh gas uncoupling by electronically interrupting or diverting FGF during inspiratory phase
81
___ and ___ caused by expanding hoses explain why delivered TV are frequently less than desired.
gas compression
compliance volume losses
82
Loss of ___ is greatest and most variable in machiens that have an external ventilator connected to a circuit that includes a soda lime absorber and humidifer.
TV - the total volume of gas that may be compressed in the circuit often exceeds 6 L
83
For every 10 cmH2O pressure, approximately ___% of the compressible volume is lost from teh circuit.
1%
84
These TV losses typically are overcome by default of FGF (in a fresh gas uncouple ventilator), which at ____L/min would add 100 mL to the circuit during a _ second of inspriation period.
3 L/min
2 second
85
What are the 3 ventilaotr mode categories?
controlled breathing
assisted or supported
spontaneous breathing
86
___ is the fixed parameter in VCV.
volume
87
With VCV what other vent parameters must be set?
TV
RR
I:E ratio
88
With VCV, airway pressure rises ____ with time as the gas volume is pushed into the lung.
linearly
89
With VCV, the peak airway pressure is direclty r/t ____ and inversely r/t ____.
airway resistance
lung compliance
90
With PCV, the fixed parameter is what?
pressure
91
In pressure control ventilation, the ____ is controlled.
peak airway pressure
92
What ventilator parameters must be set with PCV?
peak airway pressure
RR
I:E ratio
93
With PCV, ____ are delivered at the start of inspiration, and the flow is rapidly diminished with maintaining _____.
high flows
constant pressure
94
With PCV, flow tends to decrease ___.
exponentially
95
With PCV, the TV is directly proportional to ____ and inversly proportional to _____.
lung compliance
airway resistance
96
Which vent mode allows the ventilator to change the inspiratory pressure dynamically based on the compliance fo the respiratory system?
Volume guarantee PCV
97
In a steady-state system using PCV, a sudden increase in pulmonary compliance would lead to what?
Large TV
hyperventilation
98
What mode decreases patient-ventilator dyssynchrony and minimizes coughing, bucking, and straining?
Assisted and support ventilator mdoes
99
The transition from effortless breathing to spontaneous breathing during emergence is commonly associated w/ risks of ___, ___, and ____
hypoxemia
hypercarbia
dyssynchrony
100
In assisted control ventilation (ACV), the patient's effort to breath is manifested as ______in the airway pressure, and a predetermined negative pressure triggers the vent to deliver a ____.
a negative deflection
set TV
101
W/ ACV, as long at the patient triggers the vent more than the interval defined by the set control rate, a controlled breath _____ delivered.
will not
102
ACV minute ventilation =
sum of delivered control breaths + patient's triggered breaths
103
With proportional assisted ventilation (PAV), the ____ correlates with respiratory effort.
TV
A more negative effort is rewarded w/ greater TV.
104
Pressure support ventilation (PSV) is the pressure equivalent of ___.
AV
105
What vent parameters are set with PSV mode?
inspiratory time
peak airway pressure
trigger
106
In ______, the clinician sets mandatory ventilator breaths by either volume or pressure at a defined rate and inspiratory time.
Intermittent mandatory ventilation (IMV)
107
What is the problem with IMV mode?
risk of patient receiving a mandatory breath while not having completed a spontaneous or assisted breath
108
To avoid breath stackin in IMV mode, what was created?
SIMV
109
What parameters must be set with SIMV mode?
mandatory volume or pressure
RR
inspiratory time
110
With SIMV, if the pressure or flow does not exceed the set limit parameters, teh mandatory breath is delivered at _____.
the beginning of the respiratory interval
111
With SIMV, if the pressure or flow exceeds the set parameter, teh mandatory breath is delivered at ___.
the end of the respiratory interval
112
____, ___, ___, ____ can be monitored for all phases of anesthetic managment in which the patient spontaneously breaths.
pressure
volume
flow
RR
113
the CPAP number represents the ____ between exhalation adn inhalation, when the gas flow within the airway is zero
airway pressur
114
With CPAP, when the pt inhales, a ___ is created within the airway in relation to the set CPAP number, allowing gas to flow into the patient.
relatively negative pressure
115
With CPAP, when the patient exhales, the airway pressure ____ the set CPAP number allowing gas to exit.
exceeds
116
On the anesthesia workstation, how is CPAP set?
manually w/ the adjustable pressure-limiting valve (APL)
117
What can CPAP help do?
recruit alveoli
facilitate oxygenation
118
On the pressure-volume curve, CPAP can shift function to the ___ and allow the best compliance characteristics of the lung to be manifested.
right
119
CPAP can decrease what?
venous return adn CO
120
High-frequency ventilaiton is generally defined as ____ breath cycles/min but has technically been defined by the FDA as a rate exceeding ___ breath cycles per minutes.
60-3000
150
121
____ uses a nasotracheal tube or catheter w/o side holes to insufflate a controlled anesthestic gas mix. Small TV and rates of 60-120 breaths/min are used. Inspiration is active and exhalation is passive.
high frequency positive pressure ventilation(HFPPV)
122
What are the 3 types of high frequency ventilations?
HFPPV
High frequency jet ventilation (HFJV)
High frequency oscillatory ventilation (HFO)
123
____ uses the highest frequencies, smallest volumes, and active expiratory phase through oscillation using piston pumps or diaphragms
HFO
124
HFO has rate of ____ cycles/min
400-2400
125
T/F: in HFO, sinusoidal waveforms w/ I:E ratio of 1:1 are generated
true
126
What are 3 advantages to high frequency ventilation?
low airway pressures for bullous lung dx
small excursions for peripheral lung surgery
prevention of barotrauma in neonates
127
With airway pressure-release ventilation (APRV), during the inspiratory cycle, _____ is delivered for a preset period of time.
high pressure CPAP
128
WIth APRV, during expiration, ____ is released to a lower pressure for the time of exhalation.
airway pressure
129
When can overpressurization of the airway occur? (3 things)
coughing against the vent
vent settings excessive for the first breath
when the O2 flush button is pressed during inspiratory phase
