Midterm Flashcards
What is the angle of the needle when performing a ABG on the radial artery?
45 degrees
what is the angle of the needle when performing an ABG on the brachial artery?
60 degrees
What is the angle of the needle when performing an ABG on the femoral artery?
90 degrees
What is the guage of the needle when performing an ABG on the brachial artery?
20-22
What is the gauge of the needle when performing an ABG on the femoral artery?
20
What is the gauge of the needle when performing an ABG on a radial artery?
22-25
T/F: A 25 gauge needle is larger than a 14 gauge needle
False. As the gauge number increases, the size of the needle decreases
What are the primary reasons for drawing an ABG?
Ventilation
Oxygenation
Acid base balance
Disease severity
Therapy implications
What is the primary site chosen in adults and children for ABGs?
The radial artery
Why is the radial artery the first choice for an ABG?
The hand has collateral circulation due to the presence of the ulnar artery which will facilitate blood flow in the case where the radial artery is severely damaged
w do you assess a patient for collateral blood flow?
Modified allens test
Block radial and ulnar arteries for a few seconds while patient makes a fist and then release the ulnar artery. The palm should rapidly become pink
What would a negative result on the modified allens test look like?
the palm of the patient would remain blanched and not become pink after allowing flow through the ulnar artery
What are the most common hazards associated with ABGs?
Pain
Bleeding
Infection
Hematoma
What are common medications that prevent clotting?
Heparin
Warfin
Asperin
Xaralto
What laboratory results do we look at to associate a patients risk of bleeding?
Platelet count
Prothrombin time
Partial thromboplastin time
International normalized ratio
What is the normal range for prothrombin time?
13-15 seconds
Below what platelet count should you consult a physician regarding taking an ABG?
<50,000
What is the normal range for platelet counts?
150k-400k
What factors can negatively affect the accuracy of an ABG?
Air bubbles
Delayed analysis
Liquid heparin
What is the normal partial thromboplastin time?
22-29 sec
A prothrombin time of what would contraindicate drawing an ABG?
> 30 sec
A partial thromboplastin time of what would contraindicate drawing an ABG?
> 60 sec
What effect can air bubbles have on an ABG?
Increases pH
Decreases PaCO2
Moves PaO2 toward 150 mmHg
What effect can a delayed analysis have on an ABG?
Decrease in pH
Increase in PaCO2
Decrease in PaO2
hat effect can liquid heparin have on an ABG?
Decrease pH towards 7
Decreases PaCO2 toward 0
Moves PaO2 toward 150 mmHg
What are the primary pieces of clinically relevant information that can be gained from an ABG?
Partial pressure of oxygen
Partial pressure of CO2
pH
HCO3
What are the 2 primary assessment pieces of information gathered from an ABG?
Acid base balance
Oxygenation
What is the normal range for pH of human blood?
7.35-7.45
Describe the relationship between the partial pressure of CO2 and pH
Inverse
Increase in PaCO2 = decrease in pH
What is the normal level of HCO3 in the blood?
22-26 mEq/L
What is the relationship between HCO3 and pH?
Direct
Increase in HCO3 = Increase in pH
T/F: Oxygenation has no relation to pH
True
At what PaO2 is a patient considered mildly hypoxic?
60-80
At what PaO2 is a patient considered moderately hypoxic?
40-59
At what PaO2 is a patient considered severely hypoxic?
<40
What are the steps for ABG interpretation?
Assess pH
Assess PaCO2
Assess HCO3-
Do the arrow thing. Opposite = Respiratory, Same = Metabolic
Oxygen assessment
Describe full compensation
Full compensation is when the pH has returned to a normal level due to changes in respiration of bicarbonate levels
What are the benefits of an A-line?
Easy access for blood sampling
Continuous monitoring of arterial blood pressure
Describe partial compensation
The buffering organ is outside of its normal range, but pH is still not quite normal
Describe what a mode is on a ventilator
A set of instructions that tells a ventilator how to deliver a breath
Describe what a trigger is
A trigger is a qualifying event that the ventilator identifies as a signal to deliver a breath
What are the 5 ways a breath can be triggered?
Time
Manually
Pressure
Flow
Electric activity of the diaphragm
How does a patient trigger a breath with pressure?
Patient inhalation causes a pressure drop in the circuit resulting in a breath being triggered
ow does a patient trigger a breath with flow?
Patient sips some flow away from bias flow in the circuit
I have no fucking idea what this means
Describe what happens after a breath is triggered
Expiratory valve closes
Pressure/flow are introduced into the circuit
Circuit is pressurized
Lungs expand
Describe what a cycle is in terms of breath delivery
A cycle is the end of the DELIVERY of a breath, not the end of a total cycle of breath
What can cause cycling of a breath?
Time
Volume
Flow
Violation of a rule
What are the components of total cycle time?
I-time
E-time
What are the 5 basic ventilator settings?
target
PEEP
Rate
FiO2
What capacity is preserved by PEEP?
FRC
How is PEEP maintained on the ventilator?
The exhalation valve preserves a preset level of pressure once the flow of exhalation has been released
The vent circuit still carries some level of flow after exhalation even though a new breath is not being delivered
How does cardiac output change during negative pressure inspiration and positive pressure inspiration? Why?
The cardiac output during negative pressure inspiration will be greater because the negative pressure generated by the movement of the chest away from the lungs will result in a negative intrapulmonary pressure which will result in the vessels and chambers of the heart being pulled on slightly and expanded allowing for more blood flow. The opposite occurs during positive pressure inspiration where gas is forced into the lungs resulting in positive pressure being applied to the heart and vessels restricting flow and compromising cardiac output
Describe what happens to intrapleural pressure during inspiration and expiration with an unassisted breath
At base level there is a negative pressure in the intrapleural space due to the elastic recoil of the lungs inward and the chest wall outward. During inspiration, the chest wall moves outward pulling on the intrapleural space creating an increase in negative pressure. As the breath is released, the chest wall recoils inward resulting in a decrease in the negative pressure experienced in the pleural space
Describe what happens to intrapulmonary pressure during unassisted breathing
during inspiration, intrapulmonary pressure drops as the lungs are pulled outwards by the expansion of the chest wall, however at the end of inspiration the pressure has returned to zero. During expiration, the intrapulmonary pressure climbs above zero briefly due to the elastic recoil of the lungs and chest wall pushing on the pulmonary vessels briefly. The pressure elevates to 5 cmH20 briefly but returns to zero
Describe what happens to the pleural pressure during a positive pressure breath
During a positive pressure breath, the pleural pressure goes from being negative (which is where it is normally) to being positive
Describe how gas is distributed during a positive pressure breath when a patient is supine and why
region of the lungs and decreased perfusion towards the ventral region of the lungs. During a positive pressure breath, the positive pressure will open the portion of the lungs with the greatest compliance which are the portions in the ventral region. These portions are less perfused than the dorsal portions which will result in a VQ mismatch
What is the definition of transairway pressure?
The pressure required to produced airflow in the airways or
The pressure pressure required to overcome the resistance of the airway
What is the formula for transairway pressure?
PIP-Plat
What is the definition of transthoracic pressure?
The pressure required to expand or contract the lungs and the chest wall at the same time
What is the formula for transthoracic pressure
Plat-PEEP
What is trans respiratory pressure?
The pressure applied to the airway opening by a ventilator, BiPAP or BVM to expand the lungs and chest
What is the formula for transrespiratory pressure?
Transrespiratory pressure = transthoracic pressure + transairway pressure
What disease processes result in low compliance?
ILD
Pneumonia
pleural effusion
What is an assisted breath?
A breath is assisted if the ventilator provides some or all of the work of breathing
What is a mandatory breath?
A breath that is shaped by the machine outside of the patients control which is following the modes instructions
What does PC-CMV stand for?
Pressure control - continuous mandatory ventilation
What is a spontaneous breath?
A breath shaped by some degree by the patient
Patient triggered
Flow cycled
What is the control variable when using PC-CMV?
Pressure
What cycles the breath when using PC-CMV?
Time
What triggers the breath when using PC-CMV?
Time
Patient trigger
What is the control variable when using PC-CMV on adults?
Pressure delivered over PEEP (for adults)
What is the control variable for PC-CMV for peds?
Total PIP = PEEP plus added pressure
Describe the generic flow wave in a PC-CMV breath
Flow is front loaded
Flow is then responsive rather than fixed to maintain the pressure set by the RT
What does the pressure wave look like on PC-CMV?
Flat topped, indicates that once target pressure is reached it is held for the total Itime and then released when the breath is cycled via time
what determines and can affect tidal volume when using PC-CMV?
Pressure determines tidal volume
Can be affected by patient condition such as airway resistance or increased/decreased elastance
What are the ordered settings for PC-CMV?
PC
Rate
PEEP
FiO2
Itime (maybe)
What additional settings do you have to work with when using PC-CMV?
Itime
Rise time
Patient trigger
What is rise time?
Rise time is the time it takes for a pressure control breath to reach the pressure set in the mode parameters.
In what ways can Itime be set?
Seconds (milliseconds) (most frequent)
As a percentage of total cycle time
I/E ratio
What are other names for rise time because vent manufacturers are massive cucks who cant agree on one god damn naming convention?
Rise time
Pramp
Pressure rise
Inspiratory rise time
How can a patient trigger a breath when using PC-CMV?
Flow
Pressure
Electrical activity of the diaphragm
Why is it important to properly configure trigger sensitivity for a patient on mechanical ventilation?
If the trigger sensitivity is too high, the machine will deliver excess breaths
If the trigger sensitivity is too low, the machine will miss patient efforts
Describe the relative difficulty for a patient to trigger a breath on PC-CMV in regards to flow and pressure
Flow is easier for the patient to trigger a breath
Pressure is more difficult for a patient to trigger a breath
What is the control variable for VC-CMV?
Volume
What are the triggers for breaths with a patient on VC-CMV?
Time
Patient trigger
What cycles a breath in VC-CMV?
Volume
What are the settings generally ordered for a patient on VC-CMV?
Tidal volume
Rate
PEEP
FiO2
Itime (maybe)
Describe the appearance of the scalars in VC-CMV
The pressure scalar looks like a lean to with a straight roof
Flow can look like a box, however it is generally adjusted to look like a lean-to which puts more flow up front to mimic normal breathing
Volume looks like a shark fin but the forward section is a little straighter
Describe flow patterns in regard to VC-CMV
Flow is predetermined, however the delivery of the flow can be modified to either deliver constant flow (square top) or more flow up front to mimic PC-CMV flows which are more natural.
What are other settings that can be considered while using VC-CMV?
Flow wave type
Itime
Inspiratory pause
What does the vent calculate when the RT sets the Itime on the vent when in VC-CMV?
The vent calculates how much predetermined flow will be needed to meet the target Vt at the end of the Itime
When the target Vt has been met, the breath will then be cycled
What is the point of an inspiratory pause when using VC-CMV?
A zero flow state is needed to determine plateau pressure which cannot be measured if there is flow in the system
How long does an inspiratory pause need to be in order to read a plateau pressure?
As little as 0.5 seconds
Can a plateau pressure be measured when using a vent on PC-CMV?
Traditionally no. The vent will maintain the target pressure which will require some degree of flow however some vents are able to circumvent this…somehow. But mostly no. i think…
hat are the characteristics of a mandatory breath?
Ventilator controls the timing, tidal volume or inspiratory pressure
The machine triggers and cycles the breath
Note that mandatory breaths are assisted breaths
Can a patient trigger a mandatory breath?
Yes, but the vent will deliver a machine breath in CMV modes
What are the characteristics of a spontaneous breath?
Patient controls the timing and the tidal volume of the breath
Volume and/or pressure is not set by the operator but rather the patients demand and lung characteristics
What controls the volume and/or pressure during a spontaneous breath?
The patients demand and lung characteristics
T/F: a patient cannot trigger a manual breath
False, a patient can trigger a mandatory breath but will have no control over the breath delivered
T/F: when a patient is in a spontaneous breathing mode, pressure support is not offered by the ventilator
False. Pressure support may be offered by the vent at different levels by differing means
What is PC-CSV?
Pressure controlled continuous spontaneous ventilation
When using a vent in PC-CSV what triggers a breath?
The patient
What do the flow waves show in PC-CSV?
The amount of pressure support the patient is receiving
How is volume determined in PC-CSV?
Patient effort
What are other names for PC-CSV?
CPAP
CPAP with pressure support
Pressure support ventilation
SPONT
What are the ordered settings for PC-CSV?
PEEP
FiO2
Psupport
What are additional settings for PC-CSV?
Patient trigger
Rise time
PS flow cycle
Describe how flow is cycled in PC-CSV
By adjusting expiratory flow trigger sensitivity
Flow support (breath delivery) will stop at the selected flow rate
Selected flow rate is a percentage of peak flow (75%, 50%, 25%)
What is the relationship between the selected flow percentage and Itime when using a PC-CSV mode?
The higher the percentage is, the shorter the Itime will be
What happens if a patient fails to breath on PC-CSV?
A back up mode kicks in. If patient resumes spontaneous breathing, most vents will resume CSV
What is the main difference between PC-CMV and PC-CSV?
Both are instructed to reach a target pressure
Delivery in both modes is guided by rise time
BUT in PC-CSV, the patient does not have to endure a breath that is timed to be too long or too short like they might if they were in PC-CMV. They cycle the breath by changing their flow rate
What happens when a patient starts to exhale when they are on PC-CSV?
Inspiratory flow declines and the vent lets go of delivery
What happens if the vent develops a leak in the circuit?
Automatic tubing compensation or Tubing resistance compensation
Outside of OSA, when is CPAP used?
Noninvasive ventilation of patient with oxygenation problems or heart failure
Sometimes used for spontaneous breathing trials for extubation readiness
Describe IMV
Intermittent mandatory ventilation
Delivers mandatory and spontaneous breaths based on patient effort and desired rate
What are the ordered settings for PC-IMV?
Pressure
Rate
PEEP
FiO2
Itime
Pressure support
Patient trigger
Rise time
PS flow cycle
Patient effort within the trigger window is met with what kind of breath when using PC-IMV?
Spontaneous breath
How does the vent know when to deliver a breath and what kind of breath to deliver when using PC-IMV?
The mode algorithm maintains a trigger window
Patient effort within the trigger window is met with a spontaneous breath
Patient effort within the synchronization window is met with what?
A mandatory breath that counts as the rate breath
What have IMV modes historically been used for?
Weaning patients off the vent
What are the ordered settings for VC-IMV?
Tidal volume
Rate
PEEP
FiO2
Itime
Pressure support
Patient trigger
Rise time
PS flow cycle
What is a risk associated with the vent delivering too much pressure?
Barotrauma
List some alarms that would qualify as life threatening, high priority alarms that are GUARANTEED to go off right as you are about to go on lunch
Power failure
Electronic failure
Exhalation valve failure
High or low pressure from gas source
List some alarms that would qualify as life threatening, but medium priority and definitely correlated to go off when you’re about to go on a bathroom break after 6 hours
Circuit leak
Circuit occlusion
FiO2 blender failure
High or low PEEP
Humidification failure
List some non-life threatening alarms that will go off about 50 million times every shift slowly draining what is left of your sanity, your humanity, and your will to live leaving you a dried up husk of human (aka Zeke)
High or low minute ventilation
High or low tidal volume
High or low PIP
autoPEEP
What are some reasons why the high pressure alarm goes off?
Patient coughs
Secretions
Mucous plug
Patient-vent asynchrony
Where should you set the high pressure alarm
10-15 cm H2O above acceptable PIP
What are some reasons the low pressure alarm might go off?
Disconnection
Leak
Malfunctioning PEEP valve
Suctioning
What should you generally set the low pressure alarm to?
8 cm H2O
5-10 cm H2O below PIP
Why might a patient have a high minute ventilation?
Discomfort
Asynchrony
Anxiety
Pain
Waking up from anesthesia
What are some reasons a patient might be tachypneic that arent comfort related?
Neurologic conditions
Fever
Elevated metabolism
Metabolic acidosis
DKA
OVERLY SENSITIVE TRIGGER SETTING
What should the high minute ventilation alarm be set to?
10-15% above baseline minute ventilation
Why might a patient have a low minute ventilation?
Sedation
Neurologic problems
Low metabolic rate
Hypothermia
What should the low minute ventilation alarm be set to?
10-15% below guaranteed minute ventilation
Consider PBW
Why might the high tidal volume alarm go off?
Discomfort
Changes in patient condition
PC or PS set too high
Breath stacking
Why might the low tidal volume alarm go off?
Sedation
Neuro problems
Low metabolic rate
Changes in patient condition
What should the low tidal volume alarm be set to?
10-15% below set tidal volume or target tidal volume
What is the standard apnea alarm for adults?
20 seconds
What is the primary and secondary control variable when using PRVC?
Primary: Pressure with adaptable targeting
Secondary: volume with setpoint targeting
What is the trigger for patients on PRVC?
Time
Patient trigger
What cycles the breath when using PRVC?
Time
What are the ordered settings when using PRVC?
Rate
PEEP
FiO2
Itime
Patient trigger
Rise time
How does the vent determine what pressure to deliver in PRVC?
By adjusting pressure until the breath meets the target value
Breath larger than target = less pressure
Breath smaller than target = more pressure
What are the ordered settings for PRVC IMV?
Tidal volume
Rate
PEEP
FiO2
Itime
Pressure support
What are the ordered settings for APRV?
P-high
P-low
T-high
T-low
FiO2
What are the benefits of PRVC
Guarantees Vt and Ve like VC-CMV
Provides flow up front like PC-CMV
Decreases patient asynchrony
What are the settings for PR-VC IMV
Target Vt
Rate
PEEP
FiO2
Itime
Pressure support
Patient trigger
Rise time
PS Flow Cycle
What are the ordered settings for PR-VC IMV
Target Vt
Rate
PEEP
FiO2
Itime
Pressure support
What is APRV?
Airway pressure release ventilation
What are the possible settings for APRV?
P-high
P-low
T-high
T-low
FiO2
Patient trigger
Rise time
What are the ordered settings for APRV?
P-high
P-low
T-high
T-low
FiO2
PC-CMV and VC-CMV have a lot of the same settings. What settings do the two modes not have in common?
VC-CMV - Flow wave type and Inspiratory pause
PC-CMV - Rise Time and Patient trigger
What ordered settings are shared between PC-CMV and VC-CMV?
Rate
PEEP
FiO2
Itime
Which modes do not have a Rate as part of their ordered settings?
PC-CSV
APRV
Which mode incorporates an inspiratory pause into its main settings?
VC-CMV
Which modes incorporate a pressure support flow cycle?
PC-CSV
PC-IMV
VC-IMV
PRVC-IMV
What mode does not directly incorporate a PEEP setting?
APRV
PEEP might still be measurable or be able to be set, but not directly. Will find out
Which modes incorporate a pressure support setting?
PC-CSV
PC-IMV
VC-IMV
PRVC IMV
Which modes do not incorporate and Itime setting?
PC-CSV
APRV
A breath is defined as what?
A breath is one cycle of positive flow (inspiration) and negative flow (expiration) defined in terms of the flow time curve
Describe in basic terms what constitutes an assisted breath
A breath is assisted if the ventilator provides some or all of the work of breathing
What are the three basic breath sequences?
Continuous mandatory ventilation (CMV)
Intermittent mandatory ventilation (IMV)
Continuous spontaneous ventilation (CSV)
What are the 5 basic ventilatory patterns?
VC-CMV
VC-IMV
PC-CMV
PC-IMV
PC-CSV
PRVC-PS (not sure what this is, check book)
How are modes of ventilation classified?
Modes of ventilation are classified according to their control variable, breath sequence, and targeting scheme(s)
What does it mean if a patient is on full ventilatory support?
The vent is providing 100% of patients ventilatory needs
What are the advantages of having a patient on full ventilatory support?
Minimizes or eliminates patients work of breathing
Allows for ventilatory muscle rest and recovery from ventilatory muscle dysfunction
What does it mean if a vent mode has assist control?
Assist control means the patient triggers the vent to give a breath
What kind of breath will a patient receive if they trigger a breath in CMV?
They will receive the exact same breath as they would if it was a mandatory breath
What triggers a PC-CMV breath?
Time or patient
What is the target in PC-CMV?
Pressure
What cycles the breath in PC-CMV?
Time
What determines the tidal volume in PC-CMV?
The Pressure Control or Inspiratory Pressure Limit
What effect will decreased compliance have on the breath received by a patient on a PC-CMV mode? Why?
If a patients compliance decreases and the pressure setting remains the same, their tidal volume will decrease as the pressure required to reach the desirable tidal volume will be greater than what the vent is set to meet
What will happen to a patients tidal volume if their compliance increases due to their condition improving?
Their tidal volume will increase and the pressure setting on the vent will have to be decreased accordingly to ensure that the lungs are not being over inflated due to the increased compliance
What can happen to tidal volume if Itime is increased in PC-CMV?
The tidal volume may increase as a result of increased Itime due to the pressure being placed on the lungs for a longer period of time allowing for more alveoli to be recruited
What are the advantages of PC-CMV?
Provides full ventilatory support
Allows for ventilatory muscle rest and recovery
Inspiratory pressure remains constant when changes in compliance and resistance are met
Desired tidal volume can be achieved by adjusting pressure control level or Itime
What are disadvantages to PC-CMV?
Tidal volume varies when changes in patient effort, system compliance or airway resistance are present
No guaranteed minimum minute ventilation because tidal volume may vary
What happens if PEEP is increased and PIP remains the same for a patient on a vc-cmvvent on PC-CMV?
The delta P will decrease resulting in a decrease in delivered tidal volume
Why is it important to consider trigger sensitivity when adjusting settings on the vent?
Improper trigger sensitivity could result in the delivery of erroneous breaths or inadvertently increase the patients work of breathing when they are trying to get a breath but cant
What can happen if an inadequate Etime is set on the ventilator?
autoPEEP may develop
Air trapping
What triggers a breath for a patient on VC-CMV?
Patient trigger
Time trigger
How is a breath cycled with VC-CMV?
Volume
Time
How does PIP influence compliance for a patient on VC-CMV?
As a patients compliance increases, the total PIP needed to reach their desired tidal volume decreases.
As a patients compliance decreases, the total PIP needed to reach their desired tidal volume increases
What can cause an increase in PIP in patients on VC-CMV?
Decreased compliance
Secretions
What is the main advantage to VC-CMV?
Tidal volume remains constant when changes in resistance and compliance are present
Guaranteed minimum minute ventilation delivered are based set on minimum frequency and tidal volume
What are the disadvantages associated with VC-CMV?
Unsafe PIPs may occur with reduced compliance or increased resistance as tidal volumes are maintained
Unsafe plateau pressures may occur with inappropriate tidal volume settings or reduced lung compliance
Inspiratory flow rate is typically fixed and may result in patient ventilator asynchrony
What is the definition of partial ventilatory support?
Partial ventilatory support requires the patient to continue to breathe spontaneously to maintain adequate alveolar ventilation but provides enough support required to maintain appropriate CO2
What does partial ventilatory support allow for that full ventilatory support does not?
Maintains ventilation and reduces loss of ventilatory muscle strength
What kind of breaths does IMV deliver?
Spontaneous and mandatory breaths depending on patient effort and trigger settings
What are the advantages of PC-IMV?
Inspiratory pressure remains constant when changes in resistance and compliance are met
Desired tidal volume can be achieved by adjusting pressure control level
Spontaneous breathing maintains ventilatory muscle activity
Does PC-IMV provide partial or full ventilatory support?
PC-IMV provides both full and partial ventilatory support and is based on the set mandatory rate
What patients may have difficulty tolerating PC-IMV or PC-SIMV?
Patients with rapid shallow breathing
Describe breaths given with VC-IMV
Breaths can be mandatory or spontaneous
Expiration to inspiration is patient or time triggered
Breath is cycled by volume or time
What are the advantages of VC-SIMV?
Improved patient ventilatory synchrony and patient tolerance-wont put one breath on top of another
Level of support ranges from full ventilatory support, to partial ventilatory support to no support
Describe PRVC
Pressure regulated volume control
Provides volume targeted pressure control breaths using an adaptive targeting scheme
How is the desired tidal volume achieved on PRVC?
Pressure is automatically adjusted in between breaths to reach the target tidal volume based on varying compliance resistance or patient effort
When would a bed-side PFT be useful?
To assess disease progression and how it is affecting respiratory function
Evaluation for need of mechanical ventilation
Assess whether or not a patient is ready to be weaned from mechanical ventilation
What is the critical value for tidal volume based on IBW or PBW?
Less than 4-5 mL/kg
What are the critical values for respiratory rate?
< 5 or >35 bpm
How do you calculate RSBI?
RSBI = F / Vt (L)
What is a normal value for RSBI?
Equal to or less than 50
What is a critical value for RSBI?
Equal to or greater than 105
What is the normal for vital capacity in adults?
70 mL per kg in IBW or PBW
What is the critical value for vital capacity?
Less than 10-15 mL per kg
What can MIP or NIF be used for?
Monitor and assess readiness to wean vent patients
Assess the degree of respiratory muscle impairment
What pressure should a normal healthy adult be able to generate on a MIP or NIF?
-80 to -120 cmH2O
What is the critical value for MIP or NIF?
0 to -20 cmH20
Describe how you would instruct a patient to take a MIP/NIF test
Have patient exhale as much as possible
Have patient breath in as quick and hard as they can while the inspiratory port is occluded
Observe and repeat over 3 attempts or until your patient passes out.
What PFT values demonstrate a need for ventilatory support?
A vital capacity of less than 10-15 ml/kg
MIP/NIF is dropping or greater than -20 cmH2O (remember the negative)
What are the specific indications for mechanical ventilation?
apnea
acute respiratory failure
impending respiratory failure
severe oxygenation or ventilation problems
What are the main types of flow patterns?
Constant = square
Decelerating
Ascending
Sine
What is the equation for determining what FiO2 you should put a patient on who is receiving mechanical ventilation?
Desired FiO2 = Known PaO2 x Known FiO2 / Desired PaO2
What are the risks associated with high FiO2s?
Oxygen toxicity
Absorption atelectasis
Describe absorption atelectasis
Nitrogen is washed out of the alveoli by excess oxygen, oxygen dissolves into the blood resulting in a low partial pressure in the alveoli causing atelectasis
What is extrinsic PEEP?
Level of PEEP set on the ventilator
What is intrinsic PEEP
Amount of pressure in the lungs at the end of exhalation
What is total PEEP?
Extrinsic PEEP + Intrinsic PEEP
What are the functions of PEEP?
maintain/restore FRC
Enhance tissue oxygenation
Recruit alveoli and maintain them in an aerated state
A pulse oximeter reading of 90% indicates a PaO2 of what?
At least 60 mmHg
What is the minimum level of PEEP set on most patients?
2-6 cm H2O
PEEP usually set to 5
When is PEEP considered therapeutic?
When it is greater than 5 cm H2O
When considering patient oxygenation, when should you increase FiO2 and when should you increase PEEP?
Patient with a low PaO2 on less than 60% = increase FiO2
Patient with a low PaO2 on more than 60% = PEEP
What are the two options for humidifying air on a ventilator?
Heat moisture exchangers
Heated humidifiers
When performing a vent check, what should you check on the vent and in the room as part of the routine check?
Alarm settings
External alarm connection
Air and oxygen connections
Power supply
Resuscitation bag and mask
Suction
ETT secure
What is a normal range for triggering a breath using pressure on a ventilator?
-0.5 to -2.0 cm H2O
How is a breath triggered with flow?
Ventilator has bias flow which is the amount of flow available in the circuit and can recognize when there is an absence of flow due to patient effort
What is auto PEEP and when does it occur?
Auto PEEP is air trapping
Occurs in patients with a prolonged expiratory phase
What issues can auto PEEP create?
Will make triggering a breath more difficult for the patient
What effect can a leak in the circuit have?
A leak in the circuit will cause a pressure change which can result in false or auto triggering of breaths
What is rise time?
The time in which airway pressure builds to the maximum pressure value set
Where is rise time found?
Only found in pressure breaths
PCV
CSV
PRVC
BiPAP
What are the benefits of a longer Itime?
Larger tidal volume
More lung recruitment
Increased mean airway pressure
What are the cons for longer Itime?
Shorter time for exhalation can lead to air trapping
Not comfortable for patient
What is the relationship between flow and Itime?
Faster the flow = shorter the Itime
Slower the flow = longer the Itime
What factors can affect PIP?
Itime
Tidal volume
Flow
Compliance and resistance of patient lungs
What is a closed loop mode?
Vent takes information it receives from the patients and alters how it delivers the breath
What is an open loop mode?
Mode delivers a breath based on the information entered by the RT and does not respond to input from the patient
Define a set point targeting scheme
RT instructs the ventilator to deliver a certain breath, the vent delivers a breath as it was instructed
What are examples of modes with set point targeting schemes?
PC-CMV
VC-CMV
Define an adaptive targeting scheme
The delivered breath is monitored and the delivery of the next breath will be influenced by the previous breath
What are examples of modes with adaptive targeting schemes?
PRVC
Define an optimal targeting scheme
Uses an algorithm to determine the best way to deliver breaths based off the patient
What are the disadvantages of setpoint targeting?
High PIPs
Low tidal volumes
Vigilant monitoring with lots of adjustments
What are the clinical advantages of adaptive targeting?
Patient comfort
Fewer adjustments
What are the clinical advantages or PC-CMV and VC-CMV?
Guaranteed volumes
Guaranteed pressures
What are the clinical disadvantages of PC-CMV and AC-CMV?
High PIPS
Low tidal volumes
Lots of monitoring and adjustment
What are the clinical advantages of adaptive PRVC?
Patient comfort
Few adjustments
What are the clinical disadvantages of PRVC?
Works against and inappropriately chosen patient
What are the settings for VC-MMV?
Vt
RR
PEEP
FiO2
Itime
PS
Flow cycle sensitivity
Which manufacturer uses VC-MMV?
Drager
What does the operator set on VC-MMV?
Operator sets a CMV volume and rate to meet a target minute ventilation
If a patient triggers a breath on VC-MMV what will the mode do?
Deliver a pressure support breath according to the set level of pressure support
How are breaths delivered on VC-MMV?
If the patient meets the minimum minute ventilation target, all breaths will be spontaneous
If the patient does not meet the minimum minute ventilation target, mandatory breaths will be given
T/F: Mandatory breaths are not synchronized with patient effort in VC-MMV
False. In VC-MMV mandatory breaths are synchronized with patient effort
Describe a situation where VC-MMV would be appropriate to use
A patient is sedated and paralyzed. At first the patient is giving no effort because of paralyzation and the vent delivers completely mandatory breaths to meet the set minimum minute ventilation set. As the paralytic wears off, the patient will begin to give spontaneous efforts that will be pressure supported, but not enough to meet MMV so mandatory breaths will continue to be delivered in addition to spontaneously triggered breaths. When the paralytic completely wears off, the patient will be able to trigger and breath more independently resulting in mandatory breaths being reduced as spontaneous supported breaths take over
What are the targets set for VC-MMV?
Primary = Volume
Secondary = pressure
What is automode found on?
Getinge
What does automode do?
Provides seamless shifting back and forth between mandatory and spontaneous breaths in response to patient conditions
How is automode dissimilar to MMV?
It doesnt target a MV
How is automode dissimilar to IMV?
Automode drops mandatory breaths
What kind of breaths does automode deliver?
Mandatory and spontaneous
How does automode determine whether or not to deliver a mandatory or spontaneous breath?
If the patient is triggering breath at a rate greater than the set rate, all breaths will be spontaneous
If the patient is triggering breaths at a rate less than the set rate, some breaths will be spontaneous, others will be mandatory
What is ASV found on? What does it mean?
Hamilton vents
Adaptive support ventilation
What is the target of ASV?
Minute ventilation
How does ASV achieve its target?
ASV achieves it target minute ventilation by using an algorithm to tritrate rate and tidal volume to meet minute ventilation target
T/F: In ASV, the operator sets the pressure control level
False.
T/F: In ASV, the operator does not set the pressure support level
True
What default does ASV target for minute ventilation?
100 mL/Kg of IBW
Example, 70 kg patient would get 7.0 L/m as MV target
How does the vent decide what kind of breath to deliver in ASV?
Patient effort = pressure supported breath
Responds to low minute ventilation with mandatory pressure controlled breaths
What factors does the ASV algorithm determine?
Determines mandatory rate
Determines pressure to achieve Vt
Determines inspiratory time
Determines start up breath pattern
What is a safety frame in an ASV mode?
A safety frame defines acceptable combinations of rate and volume
What is the “A” variable on the safety frame in ASV?
Pressure
What are the ordered settings for ASV?
Ideal body weigh
% minute ventilation
PEEP
FiO2
Pramp
ETS
Patient trigger
What are the axes present on the ASV graph?
Y axis = volume
X axis = RR
What pieces of information are related by the safety frame on the ASV graph?
A = pressure
B = tidal volume
C = frequency
D = low rate
What are the clinical advantages of optimal targeting?
Is a very comfortable mode for the patient
Can potentially be used from intubation to extubation
Adapts to changing conditions
What types of patients would not be a good fit for ASV?
Patients with restrictive lung diseases
Patients in hypercapnic respiratory failure since rates cant be adjusted manually
Post cardiothoracic surgery patients
How does volume support provide only spontaneous breaths yet reach set tidal volume?
Volume support acts like PRVC in that it provides a titrated pressure support in order to reach a goal tidal volume
What is automatic tubing compensation?
A setting that allows you to increase inspiratory pressure to overcome the resistance of an artificial airway
How does an operator set up automatic tubing compensation?
Find setting
Enter tubing type, diameter, and length of airway
What support does automatic tubing compensation offer to a patient who is spontaneously breathing with no other support?
Helps patient overcome airway resistance provided by the artificial airway
Theres not really any good evidence that it helps and just adds to complicating the targeting scheme
Describe the AI ventilation used by dragers smart care and hamiltons intellivent
Essentially offers automated patient weaning by using AI to determine the acceptable ranges of frequency of spontaneous breathing, tidal volume, EtCO2
Titrates pressure support to keep patient in an acceptable zone
What are the steps smartcare and intellivent use to move the patient throught the weaning process?
Stabilize
Wean
Challenge
What concerns do clinicians have regarding smartcare and intellivent?
Relies on SpO2 and EtCO2 which can be spotty at best with their accuracy due to patient movement or medications the patient may be on such as blood pressure medication
What is the formula for dynamic compliance?
Cdyn = VT / PIP-PEEP
What is the formula for static compliance?
Cstat = VT / Plat-PEEP
What is the formula for airway resistance?
Raw = PIP-Plat / Flow (Liters per second)
What factors can affect a patients PaO2 when they are being mechanically ventilated?
FiO2
MAP
Lung Function
I:E time
PEEP
What factors affect mean airway pressure
PIP
PEEP
I:E ratio
RR
What is normal airway resistance in non-intubated healthy people?
0.6-2.4 cmH2O/L/sec
What is normal airway resistance in healthy intubated people?
5-12 cmH2O/L/sec
T/F: Airway obstructions can lead to autoPEEP
True
What are the main causes of autoPEEP?
Obstructive diseases
Bad vent settings
What can cause changes in Cstat?
Pulmonary edema
Atelectasis
Consolidation
Pneumonia
Pneumothorax
Hemothorax
Pleural effusion
What does the P(a-ET)CO2 tell us?
The difference between arterial CO2 and end tidal CO2
Increases in the difference indicate an increase in deadspace
What is dead space?
Ventilation without perfusion
What can cause dead space?
PE
Loss of circulation
COPD
Being dead (cardiac arrest)
How do you determine the ratio of deadspace to tidal volume
VD/VT ratio
What is the formula for the VD/VT ratio?
PaCO2 - PeTCO2 / PaCO2
What is a normal VD/VT ratio?
.2-.4
What does an elevated VD/VT ratio mean?
An increased amount of deadspace
What can cause respiratory acidosis?
Parenchymal lung disease
Airway disease
Pleural abnormalities
Chest wall abnormalities
Neuromuscular disorders
CNS depressing
What are the diagnostic benchmarks for determining respiratory acidosis?
pH < 7.35
PaCO2 > 45 mmHg
What is the formula to determine an appropriate tidal volume for a patient on a vent with respiratory acidosis?
Desired VT = (known PaCO2 x Known VT) / Desired PaCO2
What is the formula for determining an appropriate RR with a patient on a vent with respiratory acidosis?
Desired RR = (Known PaCO2 x Known RR) / Desired PaCO2
What is the risk of a high respiratory rate?
autoPEEP
How can you determine if a patient has autopeep?
On exhalation, flow will not return to zero before a new breath is given
What can cause respiratory alkalosis?
Metabolic problems
Hypoxia
Medications
CNS disorders
What are the diagnostic benchmarks for diagnosing respiratory alkalosis?
pH > 7.45
PaCO2 < 35 mmHg
What are the most common causes of respiratory alkalosis in vented patients?
hyperventilation …..oops
Pain
Fever
Asynchrony
Hypoxemia
What are the diagnostic benchmarks for determining if someone has metabolic alkalosis?
pH > 7.45
HCO3 > 26 mEq/L
What are the diagnostic benchmarks for determining if someone has metabolic acidosis?
pH < 7.35
HCO3 < 22 mEq/L
What can cause a metabolic acidosis?
Ketoacidosis
Loss of bicarb (diarrhea)
Medications
Lactic acidosis
Toxins
What can cause a metabolic acidosis?
Loss of gastric fluid (vomiting, NG suctioning)
Diuretics
Medications
Will a patient with metabolic alkalosis become apneic?
Apparently not
What are some indications for suctioning?
Patients has a weak cough
Changes in waveform
Deterioration of oxygen saturation
What is the formula for determining the correct suction catheter size?
(ETT size x 3) / 2
What is the appropriate suction pressure for adults?
-100 to -120 mmHg
What is the appropriate suction pressure for children?
-80 to -100 mmHg
What is the appropriate suction pressures for infants?
-60 to -100 mmHg
What are some potential complications from suctioning?
Your patient hating you
Atelectasis
Hypoxemia
Loss of PEEP
Cardiac arrhythmias
Bradycardia
hypo/hypertension
Infection
T/F: For a patient on a vent, a SVN is more effective than an MDI with a spacer
False. MDIs with a spacer have been shown to be more effective than SVNs
What should be considered when giving an MDI through a vent?
Whether or not an HME is being used as it will take the medication out before it reaches the patient
What are some indications for bronchoscopy?
Presence of lesions
Evaluation of atelectasis or pulmonary infiltrates
Assess upper airway patency
Suspicious sputum cytologic results
What are contraindications for a bronchoscopy?
Hemodynamic instability
Poor oxygenation
When performing a bronchoscopy, what piece of equipment should be used to maintain PEEP?
No fucking clue, slides call it a PEEP keep. Probably just need to know that you need something special to maintain PEEP
What is normal urine production?
50-60 ml/hour
1 ml/kg/hour
What is the term for low urine output?
Oliguria
What is the term for high urine output?
Polyuria
What are the 5 drivers of hypoxemia?
Low oxygen tension of inspired gas
Alveolar hypoventilation
Diffusion defect
V/Q mismatch
Shunting
T/F: Healthy individuals have a natural V/Q mismatch
True. the apical sections of the lungs will have more ventilation and less perfusion than the bases which will have more perfusion and less ventilation
What is the most common cause of hypoxemia?
V/Q mismatch
What is a shunt?
Blood that does not participate in gas exchange either because of anatomical layouts or unventilated alveoli
What is ficks law?
Vgas = A/T x Dgas(P1-P2)
Vgas = volume of gas diffusing across a membrane
A = Surface area tension
T = thickness of the membrane
Dgas = diffusibility of the gas (solubility coefficient)
P1-P2 = pressure gradient
What is circulatory hypoxia?
Hypoxia caused by not having enough blood in circulation
What is anemic hypoxia?
When you have enough blood (for now) but insufficient red blood cells in the blood
What is histoxic hypocia?
When you have sufficient blood and RBCs, but for some reason tissues are unable to use the oxygen
What are the two main tools we have to combat hypoxia?
Supplemental oxygen
PEEP
What settings on the ventilator control ventilation?
Control variable
Rate
What settings on the ventilator control oxygenation?
PEEP
FiO2
List some reactive oxygen species
Superoxide ions (O2-)
Hydrogen peroxide (H2O2)
Hydroxyl ions (OH-)
What can large amounts of reactive oxygen species do to the body?
Damage lung tissue
Disrupt cell signaling
Break strands of DNA
What can hyperoxia cause?
Systemic vasoconstriction
Pulmonary vasodilation
Inflammation
Oxidative stress on pulmonary, cardiovascular and neurological systems
Create ROS
What is the normal partial pressure of oxygen in arterial blood?
80-100 mmHg
What is the normal partial pressure of oxygen in venous blood?
40 mmHg
What is the range of the partial pressure of oxygen in the alveoli when on room air and when on 100% oxygen?
100-673 mmHg
What is the normal saturation for mixed venous blood?
75%
What is the oxygen content of arterial blood?
20 vol%
What is the oxygen content of mixed venous blood?
15 vol%
What is normal oxygen delivery? (DO2)
1000 mL/m
What is normal oxygen consumption?
250 ml/min
What are the main goals for oxygenation?
Maintain a PaO2 of 60-90 mmHg
Try to keep FiO2 below 0.5-0.6
Maintain CaO2 at 20 mg/dL
What are the main dangers of prolonged high FiO2?
Oxygen toxicity
Absorption atelectasis
Violations of mode rules that are unsafe for vent patient are likely followed by
The cycling of the breath
List the rules for safe needle handling
Never bend, break or remove used needles from syringes by hand
Never point a used needle towards any part of you body
Never recap a used needle without a safety device
Never handle a used need with both hands
PEEP serves as an approximation of
Functional residual capacity
Who the actual fuck wrote this
T/F: a positive result on a modified allens test indicates that the ulnar artery provides good blood flow
t
ABGs uniquely reveal
Acid base disturbances
You will encounter patients on heparin, warfrin and xarelto, these drugs impact the drawing of an ABG by:
Impairing the bloods ability to clot
What is the preferred order to deliver vent settings during report?
Control variable / Rate / PEEP / FiO2
Which of the following would not be used to cycle a ventilator breath? Time, Flow, Pressure or volume?
Pressure
Hazards of drawing an ABG include:
Laceration of the artery
Pain
Infection
Hemorrhage
T/F: appropriately outfitted ventilators can detect a drop in volume and respond by delivering a breath
False
T/F: appropriately outfitted ventilators can detect a drop in volume and respond by delivering a breath
False
Before entering the room to draw an ABG an RT should:
Check for an ABG order
Perform hand hygiene
Don universal precautions
When performing an ABG on the brachial artery, what angle should the needle be positioned at?
60 degrees
What can an ABG tell an RT?
When intervention is no longer necessary
When to intervene in a disease process
The success or failure of an intervention
A common cause of metabolic acidosis is
Diabetic keto acidosis
How will a large air bubble affect the PaO2 of an ABG analysis?
Move the result towards 150
You are filling out your ventilator flowsheet for a patient on PRVC. What space should be left blank?
Waveform
This question is stupid
PC-IMV delivers 2 kinds of breath. One will be time cycled, the other will be:
Flow cycled
Transairway pressure represents
The pressure required to overcome airway resistance
The difference between PEP and plat
Occurs at the AC membrane
T/F: VC-CMV requires a rise time setting
False
What happens to the heart if a patient is on positive pressure ventilation
The heart is subtly squeezed (seriously who wrote this) and cardiac output and blood pressure can drop
In mechanical ventilation, a spontaneous breath is defined:
By the trigger and cycling characteristics of the breath
What mode is good for testing whether or not a patient is ready for extubation?
CSV
For a patient breathing spontaneously with no assistance, pleural pressure at the end of inspiration is:
-10 cm H2O
To calculate transpulmonary pressure on ventilator requires
That the patient have something like an esophageal balloon placed to approximate pleural pressure
T/F: The introduction of positive pressure breathing to a supine passive patient after intubation decreases the matching of ventilation and perfusion of the lung
True. the dorsal portion of the lungs will be better perfused but less ventilated and the ventral portion of the lungs will be better ventilated and less perfused
T/F: CSV does not require that the RT set a backup mode
False. When using CSV the RT must set a backup mode in case the patient goes apneic
The plateau pressure represents:
The pressure required to hold a tidal volume against the elastic recoil of the chest
“Static” compliance
Transrespiratory pressure represents:
The difference between PIP and PEEP
T/F: Getting a VC does not require a conscious patient
False
What would be the relative values for pH, PaCO2 and HCO3 that would represent a mixed metabolic acidosis?
pH > 7.45
Low PaCO2
High HCO3
Describe the modified allens test
Compress both the radial and the ulnar arteries, then release the ulnar artery
What tests/assessments can be used to assess a patients response to oxygen therapy?
Arterial blood gas
Patient assessment
Pulse oximetry
A patient is receiving 30% FiO2 and has a PaO2 of 66 mmHg and a PaCO2 of 32 mmHg. Describe their oxygenation status
Mild hypoxia
What is being measured if you instruct a patient to take a maximum deep breath and exhale completely?
Vital capacity
After an unsuccessful ABG attempt on a patient’s right radial site. You determine that their left brachial is the next best site to attempt. What needle angle change from the radial to brachial site is required?
45 to 60 degrees
Based on the following blood gas report, what is the most likely acid-base diagnosis?
pH: 7.20
PaCO2: 51 torr
HCO3-: 19.5 mEq/L
Mixed respiratory and metabolic acidosis
A physician asks you to provide serial measurements of the respiratory muscle strength of a patient with a progressive acute neuromuscular disorder. What would you use to measure this?
Negative inspiratory force or Maximum Inspiratory Pressure
When performing a modified Allen test on the left hand of a patient, you note that her palm, fingers and thumb remain blanched for 15 seconds after releasing pressure on the collateral artery. What should you do next?
Perform the modified allens test on the right hand
Prior to drawing an ABG sample, you note that the patient has a PT of 24 seconds and PTT of 55 seconds. Which of the following actions would be appropriate in this situation?
Allow extra time after the procedure to assure hemostasis
Your patient Jeffrey is paralyzed and fully supported on mechanical ventilation. At the end of inhalation, the pressure in his alveoli is:
Positive
Transrespiratory pressure can be represented as the difference between
PIP and PEEP
A PC-CMV mode will deliver breaths to your patient Jeanine with no regard for:
The volume of the breaths
For a patient receiving positive pressure ventilation, transpulmonary pressure represent the difference between:
Palveolar - Ppleural
A vent set to VC CMV with a square wave form will deliver what kind of flow?
Constant flow
A vent set to VC CMV with a decelerating wave form will deliver what kind of flow?
Will start with a high level of flow and then decrease to a lower level of flow
In mechanical ventilation, and assisted breath is
A breath where the patient is given any kind of support
A ventilatory mode with an “open-loop” targeting scheme:
Measures the delivery of the breath to ensure it is hitting the target parameters
For a patient on a ventilator breathing spontaneous breaths, the alveolar pressure at the end of exhalation is
The same pressure as PEEP
When volume is the control variable, the breath is cycled by volume. When pressure is the control variable, the breath is cycled by:
Time
When the ventilator cycles a breath:
The breath comes to the end of its Itime
A high priority alarm should/will
Should alarm ceaselessly until corrected
Will have auditory and visual components
Will be pre programmed on the vent
Transairway pressure is equal to the difference between
PIP and Plat
You are taking care of a mechanically ventilated COPD patient with ventilator settings of: VC-IMV 700 x 8 +5 45%. In order to ensure proper equilibration between alveolar and arterial gas tensions, how long should you wait before drawing an ABG?
30 minutes
PRVC ordered settings are a target Vt, rate, PEEP, and FiO2. PRVC follows this breath pattern:
PC-CMV
What considerations are used when changing a patient from a heat moisture exchanger to a heated ventilator circuit?
Length of intubation
Suction requirements
Aerosolized medication delivery
A rise time can be found in which modes?
PC-CMV
PC-IMV
CSV
Instrinsic PEEP can be defined as:
The amount of pressure in the lungs at the end of exhalation
In pressure control ventilation, an extended inspiratory time will result in
Higher tidal volumes
Shorter expiratory time
You just assisted in intubating a cardiac arrest in the emergency room. ROSC is obtained shortly after, and you initiate the ventilator. The resident requests the patient be placed on 100% oxygen to increase oxygen delivery as much as possible. Understanding the risks associated with high FIO2, what is another way that you may improve oxygenation?
Set a therapeutic PEEP level
What risk is associated with PEEP levels that are set too high?
What are some reasons you would increase Itime
What are some reasons you would increase Itime
Increase MAP
Increase Vt
Increase lung recruitment
Your patient is being mechanically ventilated in PC-CMV. You can determine an appropriate I-time setting by:
Matching the Itime to when the flow just meets zero
T/F: PEEP can only interfere with inspiratory flow
False. It can interfere with inspiratory and expiratory flow
T/F: PEEP decreases the time needed for exhalation
False, PEEP increases the time needed for exhalation
T/F: excess PEEP can lead to barotrauma
True
T/F: PEEP increases pressure within the alveoli
True
What ventilator parameters affect MAP?
PEEP
Itime
The difference between PPlat and PEEP indicates:
“The patients elasticity”
This just sounds wrong. Its their static compliance. Compliance and elasticity are NOT THE FUCKING SAME
A patient with high airway resistance is being mechanically ventilated in VC-CMV. Which of the following would be the most likely result?
High PIP
Give some examples of closed loop ventilator modes
PRVC
ASV
Automode PC-PS
The safety of such modes as Dräger SmartCare/Pressure Support and Hamilton’s Intellivent rests on:
The accuracy of ETCO2 and/or SpO2 data input into the ventilator
What are the benefits of AI enhanced vent modes?
Fewer visits to the beside to make adjustments
Patients can move comfortably between mandatory and spontaneous breaths
Full support for patients passive to the ventilator
What settings will the ASV mode determine without operator input?
RR
Vt
PC
PS
What assumption does ASV make regarding delivered tidal volume?
That the patient has little to no alveolar dead space
With a setpoint targeting scheme, ventilator modes:
Ensure delivery of breaths defined in the mode settings
What does the curve in ASV represent?
The combinations of RR and Vt that will yield a minute ventilation target
What does automatic tube compensation require the operator to enter?
Type of artificial airway
Size of artificial airway
What can cause increases in CO2 production?
Serious bodily injuries
Fevers
Increased metabolic demand
A patient is on PC-CMV, his tidal volume is reaching 8 mL/kg and his RR is 22. Without changing his Vt or RR setting, how can you potentially increase his minute ventilation?
Increasing Itime to increase MAP which may result in more alveolar recruitment and larger tidal volumes
What can an excessive loss of gastric contents cause?
Metabolic alkalosis
A patient with metabolic acidosis will present with
An elevated RR
What conditions can cause a respiratory acidosis?
COPD exacerbation
Status asthmaticus (CUZ WE FUCKING TALKED ABOUT THIS APPARENTLY)
Flail chest (chest wall defect)
Hemothorax (less room for gas exchange)
You walk into a patients room and notice that their tidal volumes are lower than they were a couple hours ago and their PIP has increased. After putting out your cigar and finishing your bag of chips, what would you do?
Suction
What lung attributes are indications for the use of PEEP
Bilateral chest infiltrates
Recurrent atelectasis with low FRC
Reduced lung compliance
What oxygenation standards are indications for the use of PEEP?
PaO2 < 60 on an FiO2 > 0.5
P/F ratio of less than 300
Refractory hypoxemia
What is the standard (according to steves slides) for refractory hypoxemia?
An increase in PaO2 of less than 10 after an increase in FiO2 of 20%
What is the purpose of PEEP?
Increased oxygenation
Maintain acceptable PaO2
Maintain acceptable pH
Recruit alveoli
Restore FRC
How does PEEP enhance oxygenation and help maintain an acceptable pH?
PEEP can stent airways open and recruit alveoli (and prevent them from collapsing) which allows for more effective gas exchange
What are the two kinds of PEEP?
Minimum PEEP
Therapeutic PEEP
What does minimum PEEP do?
Maintains a normal residual capacity
Why is FRC reduced in intubated patients?
Physical positioning
Changes in muscle tone
Lack of Pmus
Who receives minimum PEEP?
Everyone on a vent
Who receives therapeutic PEEP?
Your mom
ARDS
Cardiogenic pulmonary edema
Bilateral diffuse PNA
Anyone with oxygenation issues
What is considered therapeutic PEEP?
Anything above 5 cm H2O
How can therapeutic PEEP be delivered?
Mask CPAP
BiPAP (that thing we still havent learned about)
HFNC (sort of)
Ventilator (duh)
T/F: PEP therapy devices can be used to increase PEEP during exhalation
True
What device is often used to provide PEEP to treat decompensated heart failure patients non-invasively?
CPAP
What population would benefit most from the PEEP provided by HFNC?
Neonates
Some evidence it works in adults, but any PEEP provided by HFNC to adults is minimal at best
What are the risks of insufficient PEEP?
Decreased static compliance
Decreased FRC
Atelectasis
Repeatedly opening and closing alveoli
What are the risks of excessive PEEP?
Decreased static compliance
Decrease venous return
Decreased CO
Decreased BP
Barotrauma
Volutrauma
What are absolute contraindications for PEEP?
Untreated or tension pneumothorax
Hypovolemia
What are relative contraindications for PEEP?
Increased intracranial pressure
Recent lung surgery (blow the stump)
Patients with emphysema
Unilateral lung disorders
