quiz 6 Flashcards
(199 cards)
1
Q
When using a pressure volume loop to determine the upper and lower inflection points, where should optimal PEEP be set?
A
2-3 cmH2O above the lower inflection point
1
Q
Describe how you would get a pressure volume curve when using the low flow or quasi-static method
A
Automated procedure requiring a paralyzed patient
Flow introduced at 2 lpm
Not static, flow low enough to generate roughly equivalent values
Proceed to 45 cmH2O
2
Q
In simple terms, what is the lower inflection point?
A
The point at which compliance improves
3
Q
In simple terms, what is the upper inflection point?
A
The point at which compliance worsens
4
Q
In simple terms what is the deflation point?
A
The point at which the alveoli close down after being inflated
5
Q
What is the difference between over distension and hyperinflation?
A
Over-distention = overstretching of lung tissue (increased alveolar tension)
Hyperinflation = inflation of the lungs beyond their usual size
6
Q
Give an example of hyperinflated lungs vs overdistended lungs
A
Hyperinflated lungs would be the lungs of a patient with Emphysema
Overdistended lungs could be the lungs of an ARDS patient who is receiving mechanical ventilation which is straining individual alveoli but not hyper inflating the lung
7
Q
What factors are evaluated during a PEEP study?
A
PEEP
FiO2
PaO2
Blood pressure
PvO2
8
Q
What increments should PEEP be weaned at?
A
Increments of 2 cmH2O
9
Q
You have a patient on 10 of PEEP and 60% FiO2. Can the PEEP on this patient be weaned?
A
PEEP should not be weaned until FiO2 is below 40%
10
Q
Why can supine positioning be problematic for some patients?
A
Decreases FRC
Decreases V/Q matching
10
Q
What are the “minor” risks associated with proning?
A
Facial edema
Patient agitation
Pressure injuries
Dislocated shoulders
Pulled out ETTs, lines, catheters
Requires experienced staff
11
Q
What recommendation is proning given by the ARDS net study?
A
Strong recommendation in patients with P/F ratios less than 150
12
Q
How can the risks of proning be minimized?
A
Wrap patients in sheet
Support with strategic pillow placement
Memory foam pillows for face
Team approach
Practice
13
Q
How does proning affect V/Q matching?
A
Improves V/Q matching by allowing better ventilation of previously closed portions of the lung
Lungs are bigger in the back so proning allows the ventral portions to be better ventilated which can improve oxygenation
14
Q
How does proning affect pleural pressure?
A
Moves the heart so that it is no longer pressing down on the lungs
Pleural pressure is more uniformly distributed promoting alveolar recruitment
15
Q
What are “major” risks associated with proning?
A
Worsening dyspnea
Hypoxemia
Cardiac arrhythmia
Increased ICP
Limited patient examination
16
Q
If you have a patient with unilateral lung disease who is satting low, how should you position them and why?
A
Position them with the good lung down to increase perfusion to the good lung
17
Q
How does mean airway pressure affect oxygenation?
A
A higher MAP increases oxygenation because it favors alveolar recruitment
17
Q
Define Mean airway pressure
A
The average airway pressure during a total respiratory cycle
18
Q
What is the formula to determine mean airway pressure?
A
Paw = (PIP-PEEP) x (Itime/Etime) + PEEP
19
Q
What is the most effective way to raise Mean airway pressure?
A
Increase PEEP
20
Q
What can you adjust to increase mean airway pressure?
A
PEEP
PIP
Itime
21
Q
Define a recruitment maneuver
A
A sustained increase in airway pressure intended to open as many collapsed lung units as possible
22
Describe how you would perform a recruitment maneuver using CPAP
20 cmH2O for 20 seconds
30 for 30 seconds
40 for 40 seconds
30 for 30 seconds
20 for 20 seconds
23
What are the two properties that govern the behavior of lung tissue?
Elastic properties and viscous properties
24
Why is time an important factor when performing a recruitment maneuver?
The lung tissue is not homogenous
The elastic behavior of the lungs is quickly activated
The viscous behavior of the lungs slows activation resulting in slowed inhalation and exhalation
25
Recruitment maneuvers in PC-CMV can be performed in 2 different ways. Describe the method that requires rapid implementation of high PEEP
Place patient in PC-CMV
Set PC to 20 cm H2O above PEEP
Increase PEEP to 40 cmH2O
Sustain for 40-60 seconds
Decrease PEEP to a level that will sustain recruitment
26
Recruitment maneuvers in PC-CMV can be performed in 2 different ways. Describe the method that requires incremental increases in PEEP
Place patient in PC-CMV
Increase PEEP by 5 cmH2O and hold for 2-5 minutes
Repeat increase with other parameters held constant
Monitor for changes in compliance
27
Describe periodic recruitment maneuvers
Aka periodic hyperinflation
Larger than normal tidal volumes delivered periodically to protect again atelectasis
28
What correlation did one study find between sustained high PEEP and blood pressure?
One study found that the benefits of sustained high PEEP are found in the first 10 seconds of the maneuver and that blood pressure decreases after those ten seconds
29
What is APRV?
Airway pressure release ventilation
30
What is TCAV?
Time controlled adaptive ventilation
31
Describe the breathing pattern in APRV
Sustained inspiratory pressure to benefit oxygenation with brief releases of the pressure to release carbon dioxide
32
How does APRV increase alveolar recruitment?
Increases alveolar recruitment through extended inspiratory times
33
How does APRV maintain alveolar stability?
By only allowing for a brief period of exhalation to release carbon dioxide, APRV prevents the alveoli from being able to completely deflate and collapse
34
How is rate set in APRV?
By manipulating Thigh and Tlow
34
What are the ordered settings for APRV?
Thigh
Tlow
Phigh
Plow
FiO2
35
How do you set Phigh?
From VC CMV = use Pplat
From PC CMV = use peak pressure
From PRVC = use peak pressure
36
What do you set Plow to?
Zero
37
How do you set Tlow?
Read the peak expiratory flow
Take that number and multiply by 0.75
The number calculated should be where exhalation ends
37
Describe the slope you would see in a patient on APRV if they have normal lungs
The slope should be about 45 degrees
38
Describe the slope you would see in a patient on APRV if they had decreased compliance
The slope would be “steeper”
Slide calls it 30 degrees, which only makes sense if you are measuring from the y axis, so keep that in mind
39
How do you set Thigh?
Calculate TCT from old mode
Subtract Tlow you calculated from old TCT
The difference is Thigh
40
What did the study on pigs with ARDS ventilated on APRV TCAV vs ARDSnet protocols demonstrate?
Compliance was better on APRV
41
Why did APRV TCAV work better on pigs than ARDSnet?
Alveoli need time to recruit, the sustained inspiratory pressure of APRV with the short exhalation periods allowed for the alveoli to be recruited and stay open
In short, MAP was increased
42
What patients might find APRV more comfortable?
Critically ill patients with a very high respiratory rate may find APRV more comfortable
42
What can Tlow tell us about the compliance of the lung?
Shorter Tlow indicates lower compliance
Longer Tlow indicates higher compliance
43
What are the benefits of spontaneous breathing on APRV?
Aids in recruitment
Helps maintain negative pressure in pleural space
Supports venous return
44
What are some of the risks associated with ARPV?
Higher MAP can mean decreased cardiac output
Minute ventilation tends to be lower on APRV than on other modes creating problems with ventilation
45
If you want to increase the RR on APRV, what would you do?
Decrease Thigh
46
What are the different kinds of non-invasive respiratory support?
HHFNC
CPAP
BiPAP
Negative pressure ventilation
47
If you want to increase tidal volume on APRV, what would you do?
Increase Phigh
48
What is NPPV?
Noninvasive positive pressure ventilation
49
What is NIV?
Noninvasive ventilation
50
What is BiPAP?
Bilevel positive pressure ventilation
51
In order for a patient to be on CPAP, they must be what?
Spontaneously breathing
52
What kind of interfaces can be used with CPAP?
Oronasal mask
Hybrid mask
Total face mask
Nasal pillows
Nasal mask
53
CPAP can also be thought of as
EPAP
PEEP
54
What does the positive pressure of CPAP do?
Stent open the airways
Increase FRC by recruiting alveoli
Improve gas exchange
Reduce diaphragmatic work
55
What are the indications for CPAP?
Atelectasis
Acute hypoxemic respiratory failure
Acute cardiogenic pulmonary edema
56
How does CPAP help patients with sleep apnea?
Eliminates soft tissue obstruction in the upper airway
56
How does CPAP help patients with cardiogenic pulmonary edema?
Continuous pressure can help push back the fluid in the lungs
57
What are the initial CPAP settings for PEEP and FiO2?
PEEP = 5-10 cm H2O
FiO2 = either match what they were on previously if on supplemental oxygen or start at 100% and wean down
58
List the interfaces that can be used for BiPAP
Oronasal mask
Nasal mask
Helmet
Total facemask
Hybrid mask
Helmet
Nasal pillows
59
What are the two pressure supplied by BiPAP?
IPAP
EPAP
60
What is EPAP equivalent to?
CPAP
PEEP
61
What is IPAP equivalent to?
PIP
Pressure support
62
EPAP is meant to improve patient ______
Oxygenation
63
IPAP is mean to improve patient ______
Ventilation
64
How does IPAP improve patient ventilation?
Pressure support
Increases tidal volume
Decreases WOB
65
When is BiPAP shown to have the most useful implimentation?
COPD
ACPE
Post op respiratory failure
Prevention of post extubation respiratory failure
66
What are the basic initial settings for BiPAP?
EPAP = 5-10 cmH2O
IPAP = 10-15 cmH2O
FiO2 = Start high and wean
67
What should the minimal pressure difference between IPAP and EPAP be?
At least 5 cmH2O
68
What is the number one reason a patient will fail on CPAP or BiPAP?
Wont comply or tolerate mask
69
What are the benefits of HHFNC?
Provide precise FiO2
Flowshes CO2 from anatomic dead space
Decrease upper airway resistance
Increase pharyngeal pressure and lung volume
Added humidity
70
What are the clinical indications for HHFNC?
Acute hypoxemic respiratory failure
Risk of hypoxemic respiratory failure post extubation
71
What are the flow settings on HHFNC for adults?
1-40 lpm, 60 max
72
What are the flow settings on HHFNC for pediatrics?
1-20 lpm
73
What are the flow settings on HHFNC for infants?
1-8 lpm
74
What are the benefits of increasing the flow when using a HHFNC?
Decrease WOB
Improve oxygenation
Improve ventilation
75
What is an example of some devices that uses negative pressure ventilation?
The iron lung
Chest cuirass
Hayek ventilator
Pneumosuit
76
What are the initial settings when using a negative pressure ventilation device?
Rate of 12-24 bpm
Inspiratory pressure of -10 to -35 cm H2O
77
What are the advantages of NPV?
Simplicity of device
Maintenance of the airway
Allows patient to eat and talk
78
What are the disadvantages of NPV?
Bulky large machine
Access to patient is limited
Reduced venous return
Upper airway soft tissue obstruction
79
what driving pressure has been associated with increased survival in patients with ARDS?
less than or equal to 15 mmHg
80
How do you calculate driving pressure?
Driving pressure = Plat - PEEP
81
How do you calculate compliance?
Change in volume / change in pressure
82
How do you calculate resistance?
Change in pressure / flow in liters per second
83
When using NIV what are the two sources of leaks?
Leak around mask
Leak built into the circuit
83
What are some possible indications for NIV?
COPD
Acute asthma
Cardiogenic pulmonary edema
Immunocompromised patients in respiratory failure
Post extubation vent support
Preintubation vent support to avoid acute desaturation
84
What are some contraindications for NIV?
Inability to protect airway
Inability to clear secretions
Poor neurological status
Significant facial trauma
Cardiac or respiratory arrest
Unstable hemodynamic status
Untreated pneumothorax
85
What is APAP?
Autopostive airway pressure
A mode of CPAP
Auto titrates pressure and adjusts to changes in phrayngeal wall vibrations, inspiratory flow limitation, hypopnea, apnea
86
What is ramp time in regards to CPAP?
Amount of time the machine takes to reach maximum set pressure
Lets patients acclimate
87
What are the three modes on BiPAP (V60)?
Spontaneous/Timed
PCV
AVAPS
88
Describe the spontaneous/timed BiPAP mode
Pressure support with backup rate
Flow cycled (if triggering breaths) time cycled if not
89
What are the ordered setting in Spontaneous/timed?
IPAP
EPAP
FiO2
Rate
Itime
Rise
Ramp
90
If a patients breaths are blue, what does that mean? (bipap V60)
Spontaneous breathing
91
If the patients breaths are orange, what does that mean? (BiPAP V60)
Timed breaths
92
What is PCV on a V60 BiPAP?
Pressure control Ventilation
All breaths are mandatory
Can be patient or time triggered
93
What are the ordered settings for PCV on BiPAP V60?
IPAP
EPAP
FiO2
Rate
I time
Rise
Ramp
94
What is AVAPS?
Average volume assured pressure support
95
What mode on a ventilator do AVAPS mimic?
PRVC
96
What are the ordered settings for AVAPS?
Rate
EPAP
Itime
Minimum P
Maximum P
Rise
FiO2
97
What can cause asynchrony when a patient is on a BiPAP?
Inappropriate cycling
Trigger asynchrony
Autotriggering if vent is too sensitive
98
What can cause inappropriate cycling on a BiPAP?
Inspiratory times that are too long/short
Leak that cannot be compensated for by the machine
99
What can cause trigger asynchrony on a BiPAP?
Inappropriate trigger thresholds
Leak around the mask
100
What factors can affect NPPV compliance?
Poor patient understanding/education
Improper interface size, selection and fit
Drying of nose and mouth
High inward flow during exhalation
High fear and anxiety
101
What are the most common complications of using NPPV?
Skin issues
102
Besides skin issues, what are other complications associated with NPPV?
Nasal irritation
Dry mouth
Painful pressure in ears
Gastric bloating
Claustrophobia
Eye irritation
Air leak
103
What are some ways to avoid skin breakdown when using NPPV?
Routinely check site
Apply barrier
Rotation of masks (different mask types
104
What questions should we be asking ourselves when determining if a patient is ready to be weaned from the vent?
Has the underlying cause for respiratory failure been reversed?
Is the patient adequately oxygenating and ventilating?
Is the patient hemodynamically stable?
Is the patient capable of spontaneous effort?
104
How can we determine whether or not the underlying cause of intubation has been reversed?
The best way is to check a patients progress in their chart. Information like their history of vent settings, past xrays, ABGs, labs, vital signs medications and fluid balance all play a part in determining if they are ready for an SBT or extubation
105
What signs that a patient on NPPV should be intubated?
Maxed out NVVP settings
Patient fatigue
Continuing acidosis or hypoxemia
Hemodynamic instability
106
A patient who is adequately oxygenating should have a P/F ratio of?
Greater than 150-200
107
A patient who is adequately oxygenating and ventilating should have a PEEP of
Less than or equal to 8 cmH2O
108
A patient who is adequately oxygenating should have an FiO2 on the ventilator of
Less than or equal to 40%
109
A patient who is adequately ventilating should have a pH of
Greater than 7.25
110
What is weaning
The gradual reduction of ventilatory support from a patient whose condition is improving
111
What does it mean if a patient is capable of spontaneous effort?
That the chemoreceptors in their brain are successfully signaling their respiratory muscles to inhale and exhale
112
T/F: A patient can require ventilatory support and weaning can begin
True
113
What are the 3 primary options for weaning?
IMV
PSV
T-piece trials
114
T/F: the majority of patients who have been intubated cannot be extubated for at least a week
False. 80% of patients do not require gradual weaning
115
Patients who are able to be extubated without gradual weaning are frequently
Post op patients
Uncomplicated drug overdose
Non respiratory cause for intubation
116
What was the original strategy when using SIMV to wean patients?
Gradual reduce mandatory breaths to increase patients spontaneous breaths while giving them support and rest with mandatory breaths
117
What have we learned about weaning using IMV?
IMV extends the patients time on the ventilator
118
What unintended consequences did IMV have?
Increased patient effort
Increased asynchrony
Increased respiratory rate
119
Describe PSV weaning
Clinician adjusts the ventilatory workload for spontaneous breaths
120
Describe T-piece weaning
Place patient on t-piece for 5-10 minutes and gradually increase the time spent on the t piece
121
What is the goal of PSV weaning
Enhance the endurance of the respiratory muscles while limiting fatigue
122
What controls the frequency timing and depth of each breath in PSV?
The patient
123
What triggers the breath in PSV?
The patient
124
What cycles the breath in PSV
Flow
125
What limits the breath in PSV?
Pressure support
126
What score on a MIP should a patient be able to accomplish in order for weaning?
MIP> -20
127
What vital capacity should a patient be capable of in order for weaning?
> 15 mL/kg
128
What frequency should a patient be breathing at in order to be considered for weaning?
<35
129
What should the patients RSBI be in order to be weaned?
<30-105
130
What are the general settings that a patient on a SBT should be placed on?
PS 5-8 cmH2O
PEEP 5-8 cmH2O
FiO2 <40-50%
130
How should you screen patients for extubation (besides checking all the normal parameters)?
Place patient on SBT for 2-5 minutes and see how they respond while assessing breathing pattern, vital signs and comfort
131
How long should a SBT last for?
30-120 minutes
132
What gas exchange parameters indicate that the SBT is successful?
SpO2 > 85-90%
PaO2 of 50-60 mmHg
Increase in PaCO2 of less than 10 mmHg
133
What hemodynamic indices are acceptable for a successful SBT?
HR < 120-140 with less than 20% change
Systolic BP < 180 and >90
134
What ventilatory pattern is indicative of a successful SBT?
RR < 30-35
Change in rate of < 50%
135
What are indications of a failed SBT?
A change in mental status
Discomfort
Increased WOB
136
What are common post extubation complications?
hoarseness
Sore throat
Cough
137
What medications can be used to control swelling post extubation if the patient's airway is swollen?
Racemic epinephrine
Steroids
138
What are some more serious post extubation complications?
Subglottic edema
Airway obstruction
Laryngospasm
Secretion management
139
What are some non invasive strategies for extubating patients?
Extubate to bipap
Extubate to HHFNC
140
Why might a recently intubated patient receive heliox?
Helium has a lower density than nitrogen which allows it to flow past obstructions with less resistance making breathing easier
141
Why could the termination of invasive mechanical ventilation increase stress on the cardiovascular system?
The positive pressure from the ventilator decreased venous return to the heart decreasing cardiac output and making the amount of work the heart had to do decrease. By removing the positive pressure, the venous return increases and therefore the amount of work the heart will have to do also increases
142
What factors may cause a patient to fail a SBT?
Cardiac factors
acid-base/metabolic factors
Drugs
Nutritional status
Psychological factors
143
Describe how issues with acid base balances can be caused by mechanical ventilation and how they can result in failure of SBTs or extubations
It is easy to hyperventilate patients who had previously been hypercapnic
This can result in a respiratory alkalosis or their kidneys decreasing the output of bicarbonate
Can also cause apnea due to removal of hypoxic drive post extubation
144
What does hypophosphatemia cause?
Muscular weakness
< 1.2 mmol
145
What does hypomagnesemia cause and who is at risk for having it?
Muscle weakness
Alcoholics
146
What does hypothyroidism cause?
Impairment of respiratory muscle function
Blunts central chemoreceptors to hypercapnia and hypoxemia
147
How do drugs affect a patient ability to be liberated from mechanical ventilation?
Some patients are unable to effectively metabolize sedatives and neuromuscular blockers making them difficult to wean
148
What physiological problems can result in poor drug metabolism?
Renal and liver function
Sepsis
Multisystem organ failure
149
What can cause acute myopathy in mechanically ventilated patients?
High dose steroids
Long terms NM blocking agents
150
What are the complications associated with overfeeding a MV patient?
Increase O2 consumption
Increase CO2 production
Increase minute ventilation
151
Why is malnutrition an important consideration for ventilated patients?
May occur prior to hospitalization resulting in a weaker patient that will have a harder time being liberated from the ventilator
Some patients also do not tolerate tube feeds well
Tube feeds tend to be carb heavy which doesnt support muscle growth or repair
152
What percentage of ICU patients will receive a trach?
10-15%
153
What psychological factors may prevent liberation from MV?
Fear
Anxiety
Delirium
ICU psychosis
Depression
Anger
Denial sleep deprivation
154
How can psychological factors that affect MV patients be potentially mitigated
Reassurance
Positivity
Treat patient like human
155
When is a tracheostomy considered early?
Within 7 days of mechanical ventilation
156
When is a tracheostomy considered late?
After 7 days of ventilation
157
Is there evidence to suggest that an early or late tracheostomy is beneficial in preventing VAP?
No
158
What should be considered prior to traching a patient?
Whether or not it will require high levels of sedation for the patient to tolerate the trach
Whether or not they have the necessary respiratory mechanics to justify a trach
159
What are the benefits of traching a patient?
Improved psychological benefit
Increased mobility
Lower WOB
Easier facilitation of discontinuation of MV
160
Why does getting a trach decrease the work of breathing?
Shorter tube = less resistance
Less tubing means less dead space
161
What can you look at on the vent screen to determine whether or not there is a leak in the system
The volume waveform will not return to zero on exhalation
161
What are the steps to discontinuing mechanical ventilation post tracheostomy?
PSV trials to strengthen respiratory muscles
Trach collar trials
Capping trials
Decannulation
162
What alarms could a leak provoke?
Low pressure
Low tidal volume
Low minute ventilation
Low peep
163
If you think there is a leak, what should you check?
All connections
Filters for cracks
Connection to the water bag
Temp probe in place?
Humidity probe in place?
HME
Closed suction catheter
164
You get a call from the nurse saying they hear a gurgling in the back of the patients throat. What is your first thought
Leaking cuff
ETT tube movement out of place
165
What should you do if you hear a gurgle in the back of the patients throat?
Check ETT for proper depth
Verify cuff is inflated
Verify cuff/pilot line/pilot balloon are not leaking
Change tube if problem cant be resolved
166
What does autotriggering look like on the vent?
Repetitive rapid identical breaths
167
How can you resolve autotriggering?
Find the leak that repeatedly triggers delivery
168
What is artifact triggering?
Triggering caused by fluid in circuit
Triggers settings being too sensitive and picking up the movement of artifacts
169
How can you resolve artifact triggering?
Remove artifact triggering the vent
Change trigger type
Make trigger less sensitive
170
What do missed triggers look like on the vent?
Irregularities in the pressure and flow waveforms
Waves going in the wrong direction
171
What causes missed triggers?
Patient efforts that are not recognized by the vent
172
What can result from repeated missed triggers?
Patient agitation
Increased WOB
Unnecessary sedation
173
How can you resolve issues with missed triggers?
Change trigger type
Make trigger more sensitive
Reduce respiratory rate
Check for autopeep
Confirm triggered breaths are indeed triggered
174
What does double triggering look like on the vent?
Pressure and flow going negative in the middle of breath delivery
Patients maximum inspiratory effort doesnt match the vents breath delivery
175
What are some ways to resolve a double trigger?
Adjust trigger
Change modes
Increase Itime
Increase Vt
176
What is a paradoxical or reverse trigger?
Ventilator delivers a breath which stimulates the patients diaphragm and they take a breath in the middle of the breath triggering the vent again
177
How can you resolve a reverse trigger
Decrease respiratory rate
Trial PC-CSV
Reduce sedation
Paralyze patient
178
What does flow asynchrony look like on the vent?
A dip in the pressure wave in the middle of the breath
179
What causes a flow asynchrony?
A patient not being happy with the amount of flow they are receiving
180
What can a flow asynchrony cause?
Shifts WOB from vent to patient
Leads to respiratory muscle fatigue
Increased O2 consumption
181
How can you resolve flow asynchrony?
Change mode to pressure control (delivers more flow up front)
Decrease Itime to increase flow
Change flow waveform in VC
182
What is flow overshoot?
A spike in pressure at the beginning of the pressure wave
183
What causes a flow overshoot?
Flow being given faster than the patient wants it
Flow is driven faster than airway resistance or lung compliance can receive it
184
How can you resolve a flow overshoot?
Lengthen Itime in volume modes
Lengthen rise time in pressure modes
185
How can you resolve delayed cycling?
Increase expiratory flow cycle sensitivity
Increase pressure support
Patient may need to be put on a rate
186
What does delayed cycling look like on the vent?
A spike at the end of the pressure wave indicating that the patient is trying to exhale will indicate delayed cycling
A downward slope in the flow wave prior to official exhalation will indicate delayed cycling
187
What can autopeep cause?
Increase PIP
Make triggering more difficult
Volutrauma
188
