Mechanical Ventilation Flashcards
What is the goal of mechanical ventilation?
- to give supportive respiratory therapy
- Support and improve ventilation and perfusion
- Bridge to recovery or until decision of EOL
- Non curative
What is mechanical ventilation?
oxygen is moved in and out of the lung by mechanical means. It requires a endotracheal tube or a tracheostomy
What are the two types of mechanical ventilation?
Negative pressure ventilation
Positive pressure ventilation
Examples of positive pressure ventilation
- Volume ventilation or pressure ventilation
2. PEEP and CPAP (NIVVP)
Indications for mechanical ventilation are?
- Apnea
- Unprotected airway
- Acute Respiratory Failure
- Acute Respiratory Distress Syndrome (ARDS)
- Severe Hypoxemia
- Severe Respiratory Muscle fatigue/impairment
What are some examples of severe respiratory muscle fatigue/impairment?
COPD or spinal cord injury (C5, C7)
When are PEEP and CPAP commonly used?
when the patient is over sedated or can’t protect their ariway
When is volume ventilation or pressure ventilation used?
when the patient cannot breath on their own
Data related reason to ventilate
- CO2 more than 50
- O2 less than 50
- RR ineffective, more than 40
- RR less than 8
- pH 7.3 or less
Others: diminished or absent breath sounds, swallow expansion, ARDS, respiratory muscle fatigue
What is a ventilator mode?
the way that inspiration/expiration are provide or set
How do you select the ventilator mode?
- based on the patient’s individual status
2. ABG, LOC, respiratory drive, therapeutic needs
How recommend the mode?
RT and RN
What considerations do you need to incorporate when setting up. a ventilator?
- Patient weight (ideal weight for height even if skinny or overweight)
- LOC
- Patients response
6 components of ventilator settings are?
- FiO2
- Rate: frequency of breaths per minute
- Tidal volume
- Positive end-expiratory pressure
- Sensitivity
- Max pressure limits
What is tidal volume?
how much air that the patient will get with each breath
What is normal tidal volume?
MV tidal volume? ARDS tidal volume?
Normal: 5mL/kg
MV: 6-8 mL/kg
ARDS: 4-8 mL/kg
What is permissive hypercapnia?
pCO2 of 50-70mmhg
May be allowed to avoid barotrauma
What is PEEP (positive end-expiratory pressure)?
The pressure in the lungs above atmospheric pressure that exists at the end of expiration that can be kept to maintain airway patency
Keeps positive pressure on the lungs at the end of respiration cycle to keep alevoli open
Vent setting: sensitivity
amount of effort from a patient that is required to innate a breath
What happens if the max pressure limit is met?
The ventilation will release any excess pressure to avoid barotrauma
What is the usual pressure limit on MV?
10-20 cm H2O above peak inspiratory pressure
What is the goal PaO2 for a patient of MV?
above 60
The way negative ventilation works
- A device chamber surrounds the outside of the chest with negative pressure
- Chest is pulled outward and air enter the lungs
- Expiration is negative
Examples of negative ventilation
Iron lung or cuirass
Adevantages/disadvantages to negative pressure ventilation
Advantage: no artificial airway and can be done at home
Disadvantage: volume per breath can’t really be measured, uncontrolled therapy and skin damage
What patients is negative pressure ventilation commonly used for? Not used for?
Used for neuromuscular disorders like MS or MD
NOT used for critical care
How does positive pressure mechanical ventilation work?
- Positive pressure is applied to the airways at inspiration
- Intrathoracic pressure increased with inspiration as the ventilator sends measured tidal volume or breath in - this stays positive until breath ends
When is positive pressure ventilation is applied to the airways and is their expiration active or passive?
applied on inspiration and their expiration is passive
What are the two volume modes and are they used often?
- Assist control
- Synchronized intermittent mandatory ventilation (SIMV)
These are rarely used
What are the three pressure modes? Why are they more commonly used?
- Pressure support ventilation
- PEEP
- CPAP
More commonly used, safe and effective
How does assist control work?
Tidal volumes and number of breaths are set
Patient can initiate their own breaths which the set tidal volume will be given and the machine will still give the set breaths per minute
Pros and cons of assist control
Pros:
- Decrease WOB
- Some independence
Cons:
1. Hypo or hyperventilation if settings are too slow or too fast
What is the purpose of PEEP?
to make sure that the alveoli do not collapse
What is SIMV (synchronized intermittent mandatory ventilation)?
A set number of breaths with a set volume
Patient is able to breath on their own with their own volume
When is the SIMV breath delivered?
At the end of the expiration so patient is comfortable
What are the uses of SIMV?
- Weaning - allows improved synchrony between patent and ventilator
- More comfort for patient
- Used in. combo with pressure support for wean
Pros and cons for SIMV
Pros
1. Decrease positive pressure breath
Improve CO
Cons:
- Hypoventilation if rate is too low and patient is not taking own breaths
- Close monitoring
- Rate too low –> paitinet become fatigued and acidotic
Is SIMV used very often?
Not with newer ventilators, might find use of this on rehab units
What is pressure control ventilation (PCV) mode?
Set rate but tidal volumes are not set
Amount of pressure needed to provide rate is controlled
What is pressure control inverse ration?
combines pressure controlled ventilation with inverse ratio of inspiration and expiration
Normal RR is: 1:2 or 1:3
IVR is 1:1
What is IVR used in?
ARDS
What are the pros of airway pressure release ventilation (APRV)?
- Allows for release of pressure so if pt takes a giant breath then it won’t add more pressure if not needed, it will just release it
- Pt. can take a breath and the ventilator allows
- Less PPV
- Used for patients who need high pressure to open and recruit alveoli
- Decreases need for deep sedation
What are the advantages for PEEPS?
- Keeps the alveoli open by providing counter pressure to fluid extravasation
- Allows for hypercapnia
- Improves oxygenation
Indication for PEEPS
Patient can’t maintain a pO2 more than 60 mmhg on less that 50% FiO2
Optimal PEEPS is
5 cm H20
Can go as high as 20
Where is the pressure added during PEEPS and why is it important?
added to alveoli at the end of expiration
- Lung volume during expiration and between breaths increases
- FRC increase
- Alveoli are open longer or open if closed
which patients should PEEPS be used cautiously with?
increased ICP, low CO and hypovolemia
What are the disadvantages of PEEPS?
- Decreased CO
- Hemodynamic instability: hypotension and increased HR d/t decreased CO
- Barotrauma if PEEP too high
- Adverse effects and complications associated with PEEPS above 12cmH2O
- patient may be able to equilibrate within 30 minutes
Which type of patients is PEEPS commonly used on?
patient who have a pathology that predisposes their alveoli to collapse, generally d/t large amount of fluid in lungs
What is pressure support on vent settings?
preset pressure with each breath that is applied through the whole inspiratory phase to decrease WOB by decreasing airway resistance from both the artificial airway and the ventilatory circuitry
What is the point of pressure support?
reduce O2 demand and allow muscles to recover
When can pressure support be applied?
during the weaning process and other modes
Continuous positive airway pressure (CPAP)
Patient initiates own respirations with own tidal volume and rate
Positive pressure during both inspiration and expiration to keep alveoli open, prevent collapse during expiration
Can CPAP be used alone and with a vent?
yes, either applied with a MV or by accessary device
Added to ventilation mode for weaning
What is the best outcome for care while patient is on a ventilator?
The plan involves everyones!!
Interdisciplinary and collaborative team
Nursing responsibilities for artificial airway
- Maintain correct tube placement
- Maintain proper cuff inflation
- Monitor oxygenation and ventilation
- Maintain tube patently
- Assess for complications (too loose, pt. biting down)
- Provide oral care and maintain skin integrity
- Foster comfort and communication
What are two major complications of ET intubation?
- Unplanned extubation
2. Aspiration
What do you do if your patient has an unplanned extubation?
- Call for help
- monitor airway, bag, suction, intubation tray with ETT at bedside
- Make sure ETT is secure and exit mark documented
When a patient with an artificial needs tube feeding what do you need?
need to place an NG tube and get an x-ray to confirm it
Mircoaspiration can lead to..
VAP
Care for pt. on MV: respiratory assessment
- Every 1-2 hours and PRN
- Observe, auscultate, assess breath sounds, chest expansion and monitor for changes
- Airway security, ensure proper tube placement
- Monitor ABG, CXR, SpO2, EtCO2
- Assess s/s of any positive for negative changes
What s/s may you see with Resp changes on a MV? (8)
Respiratory distress Increase restlessness Secretions Change in VS Diaphoresis, Change in skin color S/S of hypoxia Hypercapnia
Care for pt. on MV: maintain airway patently and effective clearance
- Manage secretions by sanctioning
- Promote alveolar recruitment but chest PT, repositioning
- Prone positioning, lateral rotation bed used to promote used alveoli in dependent position
- Bronchodilators
Care for pt. on MV: Mobility
- Early mobility
- Turn the patient often
- Prone
- Get patient up and moving
What is the advantages to mobility while on MV?
improved outcomes, less complications, less death
Care for pt. on MV: nutrition
- Patient needs more calories d/t hyper metabolic state
How soon should feedings start and is enteral or parenteral feedings preferred?
Feeding should start within 24-48 hours of admission or intubation
Enteral feeds preferred but parenteral feeding can be used
What precaution do pts. with a Trach have at meal times?
Aspiration precautions
Care for pt. on MV: oral care
- every 2-4 hours with swab
- Scrub with Chlorhexidine (CHG) every 12 hours (every shift)
- Suction
How often should suction equipment be replaced?
every 24 hours
Care for pt. on MV: skin integrity
face, lips , tongue r/t airway and all over body for
pressure areas – protect and treat as necessary
What is the goal of the ventilator alarm?
warning or indicator of an event or important change
What should you monitor while the patient is on a ventilator?
- Check the ventilator settings frequently
- Check alarms frequently
AT LEAST once per shift
What is the safety rule of ventilator alarms?
if the cause of an alarm is not found and corrected immediately, remove patient from vent and manually ventilate using an AMBU bag until the problem is fixed
NEVER turn off alarm first, always assess the patient first!!
What could cause a high pressure alarm?
- Biting
- Secretion in the tubing
- Kinks in the tube
- Reduced compliance
- Water in circuit
- Coughing
What should you do for a high pressure alarm? (7)
- Take off vent and bag
- Suction to clear secretions
- Monitor for kinks
- Use bite lock
- Reposition
- Bronchodilator
- treat pain
What could cause a low pressure alarm?
- Circuit leaks
- Airway leaks
- Patient disconnected
What should you do with a low pressure alarm?
- Check connections
- Check cuff lead in ETT
- Normal 20-25 mmhg
What are the risks for prolonged immobility?
- DVT
- Pressure ulcer
- Contractures
- Prolonged LOS
Why is a patient on a tube restrained?
so that way the patient does not pull the tube
What is medications are used to keep the patient from moving with a tube in?
Neuromuscular blocking agent
How do you manage the mobility of a patient on a ventilator?
- Early mobility
- Turn and reposition Q2
- ROM
- Skin assessment including oral care and assessment of lips and mouth
What are the pulmonary complications with MV?
- Volutrauma/Barotrauma secondary to high TV, PEEP, noncompliant lung
- Volutrauma/Barotrauma may result in pneumothorax
What are the s/s of barotrauma?
- Sudden agitation
- Cough
- High pressure alarm
- Hypotension
- Absent breath sounds
How do you prevent barotrauma?
- Decrease TV
2. Monitor PAP (peak airway pressure)
How do you manage barotrauma?
chest tube
When does VAP occur?
48 hours or more after intubation
Complications associated with VAP
- Increased vent time
- Increased length of stay in ICU
- Increased length of stay
- Increased cost
What are the causes of VAP? (8)
- Upper airway defenses are bypassed
- Poor nutrition
- Contaminated airway upon intubation
- Contaminated equipment
- Poor hand washing
- Decreased cough
- Poor monitoring of cuff pressure
- immobility
How do you diagnose VAP?
- Chest X-ray with infiltrates on one or both sides
Clinical:
- Increase O2 requirement
- Purulent secretions
- Fever above 38
- Change in breath sounds
Micro:
- increased WBC
- Colonization sputum
What is the goal of the VAP bundle?
Prevent VAP, VTE, and stress-induced GI bleeds
What does the ventilator bundle include?
- Elevate HOB between 30-45 degrees
- Daily sedation interruption and daily assessment of readiness to extubate
- PUD prophylaxis
- DVT prophylaxis
- Oral care with Chlorhexidine
- Hand hygiene
Why is elevating the HOB important?
decreases VAP by decreasing risk of aspiration of GI contents or oropharyngeal and nasopharyngeal secretions
What should you do to prevent PUD?
- H2 blocker
- PPI
- Cytoprotective
- Sucralfate
What meds are withheld for daily sedation vacation and which are not?
Held: sedation medications
Not held: pain medication
Why are sedation vacations a thing?
- To assess neurologic readiness to extubate
2. Decrease time on ventilator –> decreased risk for VAP
DVT prophylaxis includes
- Anticoagulants
2. Compression devices
What are the parameters for weaning?
- PaO2 more than 60 mmhm on FiO2 less than 50%, PEEP of less than 8
- PaCO2 less than 45 mmhg
- RR less than 30
- Spontaneous TV more than 4-5 mL/kg
- Max inspiratory pressure (ability to cough) - 20 cm H2O
- Patient awake,alert, hemodynamically stable
What to assess the patient for while pt is on breathing trial
- Follow commands
2. Protect airway - test gag reflex if suctioning should cough
What is a spontaneous breathing trial?
allows patient to breath on their own without removing the vent
What does it mean to wean someone form the vent?
reducing ventilation support and resuming spontaneous ventilation
What are some mode for weaning?
- PRVC
- CPAP via Ventilator
- T-piece
- PSV
- SIMV
What should you monitor for while weaning?
- Weaning intolerance
- Dysrhythmias
- increase or decrease in pulse or BP
- Dyspnea, diaphoresis, restlessness
- increase in PaCO2
- PaO2 under 60 mmhg
What should you do to monitor and support a newly extubated patient for?
- Supplemental O2 and humidification
2. Pulmonary hygiene: positioning, suction, nebulizer
If patient is not tolerating the wean?
100% FiO2 and resume mechanical ventilation
What are other ARDS and ARF treatments?
- High dose steroid therapy
- Prone positioning
- Surfactant therapy
- High frequency oscillator ventilation (HFOV)
- Extracorporeal membrane oxygenation (ECMO/ECCO)
- Nitric oxide
- Neuromuscular blocking agents
