Ventilator Trouble shooting
Presented by Lily To & James Lindsey
Ventilator Troubleshooting
• Involves identification & resolution of a technical problem
• A problem is a situation in which one finds oneself in that can not be immediately corrected
Solving Ventilator Problems
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Access situation
Gather & analyze pertinent data
This information should point to a number of potential solutions
A solution should be tried – with making an observation of the patient’s response
A positive response leads to correction of the problem
A negative response – undo what was tried – find out why it didn’t work before attempting a new solution
Determining cause of the problem – helps prevent the problem from reoccurring
Protecting the Patient
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Always ensure patient safety
When alarm is triggered – check patient first
Look for LOC, increased WOB, use of accessory muscles, auscultation, SpO2, heart rate, skin color, diaphoresis
Distress - bag patient, if necessary
Check alarm & alarm settings
Identifying Patient Distress
• Notice when patient is “fighting the vent” or asynchrony
• Signs include: tachypnea, nasal flaring , diaphoresis, use of accessory muscles, retractions,
paradoxal chest abdomen movement, abnormal breath sounds, tachycardia, arrhythmia,
hypertension
Sudden Causes of Respiratory Distress
Patient – Ventilator asynchrony – Causes
Ventilator – Related Causes
• Artificial airway problems
• System leaks
• Bronchospasm
• Disconnected circuit
• Secretions
• Low FiO2
• Pulmonary edema
Improper Settings
• Pulmonary embolism
• Incorrect support mode
• Dynamic hyperinflation
• Abnormal respiratory drive
• Body positioning
• Pneumothorax
• Anxiety
• Sensitivity
• Flow
• Time cycled
• PEEP
Common Patient – Related Problems
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Airway problems
• Kinked ET tube, biting
• Displacement of tube in right lobe or upward
• Rupture of an artery
• Fistula obstructed ET tube
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Pneumothorax
• Look for increased work of breathing, nasal flaring, use of accessory muscles,
absence of breath sounds, uneven chest movement & cardiovascular assessment
Pneumothorax
• Bronchospasm
• Signs include:
• dyspnea, wheezing, increased work of breathing, paradoxical chest/abdomen movement,
retractions and increased RAW
• Secretions
• Evaluation can lead to differentiate problems
• Dry secretions – insufficient humidification?
• Copious amounts – pulmonary edema?
• Detect infection?
Common Patient – Related Problems
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Pulmonary Edema
• Cardiogenic pulmonary edema
• Sudden – thin, frothy, white to pink secretions. Follow through with additional testing – ECG, Bp,
JVD and Hx of heart disease
• Treatment includes medications to reduce preload and afterload (lasix), increase contractility (Lanoxin)
• Non-cardiogenic pulmonary edema
• Not sudden – increase in pulmonary capillary permeability (treatment similar to above)
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Dynamic Hyperinflation
• Auto-PEEP causes dynamic hyperinflation – leads to difficulty triggering ventilator & increased work of breathing
• Causes hypertension and reduced cardiac output
• Suspected when flow does not return to baseline in flow-time curve.
• Treatment: reduce TI, VE and correct RAW
• Abnormalities in Respiratory Drive
• Decrease is result of heavy sedation, neurological disorders, neuromuscular blockage
• Increase is result of pain, anxiety, peripheral sensory stimulation, medications and improper ventilator settings
Common Patient – Related Problems
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Changes in Position
• Can cause accidental extubation
• Alter oxygenation by bending, twisting circuit
• Cause mucous plugging
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Drug Induced Distress
• Can cause respiratory distress & maybe failure
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Abdominal Distention
• Distention - can be associated with other disorders that introduce air into the stomach
(ascites, GI bleed, liver & kidney problems)
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Pulmonary Embolism
• Emergency
• Leads to asynchrony
• Sudden onset – hypoxemia
• Patient presents with bilateral breath sounds, increased WOB, elevated HR,
Bp and RR
• Increasing flow and FiO2 does nothing to correct
• Treat with increased respiratory rate
• Capnography – helps us see – reduced VT & CO2
Ventilator – Related Problems
• Leaks – cuff, circuit
• Alarm activates
• Low/high pressure
• Low minute ventilation
• Inadequate Oxygenation
• SpO2 alarm
• Signs – hypoxemia
Puritan Bennet
840
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Inadequate Ventilator Support
• Causes increased work of breathing, respiratory acidosis & hypoxemia
• Leads to asynchrony
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Sensitivity
• Causes auto-triggering –setting too low - high pressure, patient can not trigger
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Flow Setting
• Air starvation – correct by increasing flow or changing flow pattern
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Drager V500
Other Problems
• Auto-PEEP – makes vent more difficult for patient to trigger a breath – correct by increasing E-time
• PSV - may cause asynchrony with certain disorders and if it is set too low
Common Alarm Situations
Normal Alarm Settings:
• V T:
high, 200ml above setting – low, 100ml below setting
• Pressure: high, 10cmH2O above PIP – low, 5cmH2O below PIP
• Rate: high, 10 bpm above setting – low, 5 bpm below setting
• Flow: high, 2L above setting – low, 2L below setting
• Apneic:
20 seconds
• FiO2: high, 5% above setting – low, 5% below setting
Common Alarm Situations
Low Pressure Alarm Causes:
• Patient disconnected
• Circuit leaks – inspiratory/expiratory circuits
• Ventilator related disconnections
• Humidifiers, filters, water traps, nebulizers, closed circuit
catheter
• Temperature monitors
• Exhalation valve leak
• Cracked, unseated, improperly connected
• Airway leaks
• Improper cuff inflation
• Cut hole in pilot balloon/ cuff
• Migration of ET tube
• Chest tube leaks
High Pressure Alarm Causes:
• Coughing
• Biting, kinking, positioning of ET tube
• Herniation of ET tube/cuff
• Increased airway resistance (secretions, edema,
bronchospasm)
• Decreased compliance (pneumothorax, pulmonary
embolism)
• Patient – ventilator asynchrony
• Accumulation of water in circuit
• Kinking in inspiratory circuit
*Most often activated by leaks*
• Malfunction with inspiratory/expiratory valves
Additional Alarms
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Low PEEP/CPAP
• Activated when airway pressure falls below desired baseline during PEEP/CPAP
• Causes include: leaks or by active inspiration
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Apnea alarm
• 20 seconds
• Causes: patient apneic or disconnection, leaks, sensitivity setting
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Low-Source Gas Pressure/ Power Alarm
• If gas or power source fails
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I:E Ratio Alarm
• Most ventilators do not allow I:E ratio to be set less than 1:1
• Causes: flow set too low for desired VT delivery
• I:E – may change with a change in waveform (constant to descending - lengthens TI in VC)
Additional Alarms
• High PEEP/CPAP alarms
• Causes are similar to those of high pressure
• flow-cycle modes , check for leaks
• Low VT, low VE or low flow alarms
• Causes are similar to low pressure alarms
• Determine if spontaneous ventilation has decreased
• Check all alarms
• Check flow sensors, disconnection/malfunction
Flow Sensor
• High VT, high VE or high flow alarms
• Check sensitivity setting, causes auto-triggering
• Check patient for possible cause of increased VE
• Check alarm settings
• If nebulizer in use, reset alarm until treatment is completed
• Check flow sensors, contamination/malfunction
• Low/high FiO2 alarms
• Check gas source
• Check built-in oxygen analyzer is functioning properly
Nebulizer
Flow-Volume
Use of Ventilator Graphics to Identify Ventilator Problems
• Ventilator graphics can alert of abnormalities before
obvious signs appear
• Flow-time & Pressure-time graphs are used for accessing
patient triggering, flow starvation, auto-PEEP, I:E time,
flow pattern, plateau time, rise times and asynchrony
• Volume-time graph accesses auto-PEEP
• Pressure-Volume loop accesses leaks, overdistention,
increased RAW, asynchrony and patient triggering
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Flow-Volume loops are used to access
obstructive/restrictive lungs, the effects of bronchodilators
and leaks
• Waveform ringing in Flow-time & Pressure-time
Occurs when flow & pressure are very high at a beginning
of a breath – a result of oscillation of air at beginning of a
breath
Use of Ventilator Graphics to ID Problems
Leaks – low pressure, low volume , low minute ventilation or apnea will trigger alarm
Pressure-Volume Loop
Flow-Volume Loop
Leak
Flow-time curve
Leak
Volume-time curve
Auto-PEEP, air trapping
Examples of additional graphic curves
Pressure-Volume Loop
Obstruction: administer bronchodilator
Overdistention
Correct: increase E-time
Overdistention
Correct: reduce volume, pressure
Unexpected Ventilator Responses
Unseated/Obstructed Expiratory Valve
• Blocked or unseated valve, unable to get expiratory pause – plateau pressure
High Tidal Volume Delivery
• Occurs with small volume nebulizer (SVN)
• Flowmeters can add extra flow – can increase tidal volume
Excessive CPAP/PEEP
• Eliminate leaks – causes application of high flow to maintain CPAP/PEEP
Nebulizer Impairment of Patient’s Ability to Trigger PSV
• Nebulizer makes it more difficult for patient to trigger ventilator
• Usually occurs with external gas sourced nebulizer
• Use manufacturer’s nebulizer if provided
Flowmeter 840
Increased VT, VE or rate alarm
N
o
Please Note always start by checking patient’s stability and is adequately ventilated
Is patient demand
VE increased
yes
Check cause of increased VE demand
to determine if change is needed
Is vent
Auto-triggering
yes
1. Check sensitivity setting
2. Check the MMV setting
Is a nebulizer
In use
yes
Adjust vent settings until
treatment is completed
Is flow sensor
malfunctioning
yes
Is alarm set
too low
yes
Check operators
Manual/contact
manufacturer
1.
2.
3.
Clean & calibrate sensor
Clear sensor line
Check its function and replace if needed
Adjust alarm setting
1. Check machine for sensitivity level for auto-triggering
2. Check for cause of increased VE
3. Ensure alarms have been properly set
4. External nebulizer used; reset alarm until treatment is completed
5. Check flow sensors for calibrations, contamination or malfunction
Low pressure. Low PEEP, low VT, low VE
N
o
Is patient disconnected
yes
Reconnect
Is there a leak in the circuit
yes
Repair/replace circuit
Is there a cuff leak
yes
Reinflate cuff/check it’s pressure –replace tube if
necessary
Is there a chest tube leak
yes
Contact physician/monitor pt
Is proximal airway pressure
line obstructed
yes
Clear the line
Is the flow sensor
malfunctioning
yes
Alarm set inappropriately
yes
Check manual/contact trained
specialist
1.
2.
3.
Clear sensor & recalibrate it
Clear sensor line & recheck
Check sensor function & replace sensor if necessary
Reset
1. Check for disconnection
2. Check for leaks in ventilator, circuits, airway & chest tubes
3. Check proximal pressure line is connected & unobstructed
4. Low-pressure maybe accompanied by a low minute volume or low tidal volume alarm
High pressure, High PEEP alarms
N
o
Is artificial airway completely obstructed
Can it be cleared
yes
Change artificial airway
Is pt coughing
yes
Suction or relieve irritation
Are there secretions in the airway
yes
Suction pt
Is the circuit obstructed
yes
Is ET tube being bitten
yes
Insert a bite block
Is the position of artificial airway altered
yes
Reposition artificial airway
Is the Raw increased or compliance increased
Continued
yes
1.
2.
1.
2.
3.
4.
Drain condensation 3. kinks in ventilator circuit
Check water traps
Assess & Correct
Secretions
5. Pulmonary edema
Bronchospasm 6. Pneumothorax
Mucosal edema 7. Pleural effusion
Pneumonia
8. Other
Continued - High pressure, High PEEP
N
o
1.
2.
3.
Check inspiratory gas flow
Check sensitivity
Check vent parameters
4. Check mode of ventilation
5. Consider sedation
1.
2.
3.
Check & treat for increased Raw (suction, bronchodilator)
Increase flow to shorten Ti and increase TE
Decrease VE
Is pt breathing
asynchronously
yes
Auto-PEEP present
yes
Is exhalation valve
malfunctioning
yes
Fix or replace valve
Is the venting pressure too
high
yes
Reduce pressure
Is alarm set too low
yes
Increase alarm setting
Check for possible causes
ET cuff blocking the end of
the artificial airway
1. Pt coughing; determine if secretions have built up in airway or pt is biting ET tube
2. Check for kinks or displacement of ET tube and circuit
3. Check to see if RAW has increased or CL has decreased
4. Check is patient is breathing synchronously with vent
5. Determine if there is auto-PEEP has developed
6. Make sure the expiratory filter & expiratory valve are functioning properly.
I:E Indicator
N
o
Is an adverse ratio desired
yes
Activate inverse ratio
Is vent time cycled
yes
Decrease inspiratory time
Is volume being used with set
flow too low
yes
Increase flow
Is volume being used with a set
volume too high
yes
Decrease volume
Is the rate too high
yes
Decrease rate
Is vent flow reduced due to
mechanical problem, increased
Raw, or decreased compliance
yes
Eval patient & vent’s performance
and correct problem
Change mode or VE parameters
1. Usually indicates I:E ratio greater than 1:1
2. If inverse is goal: disable I:E ratio limit or ignore alarm
3. If normal I:E desired: check alarm
If increased RAW/decreased CL has resulted in lower flow, tx cause
If flow is too low for desired VT, increase flow or change waveform
Apneic Alarm
N
o
Is an actual apneic episode occurring
yes
Readjust vent support
Is the alarm setting appropriate
yes
Reset alarm
Is vent insensitive to patient effort
yes
Reset the sensitivity
Is there a leak
yes
See low pressure alarms
Is flow or pressure sensor faulty
yes
Clean recalibrate, check & replace
sensor if necessary
Check operator’s manual/contact
trained technician
1. Is patient apneic
2. Check for leaks
3. Check sensitivity to make sure vent can detect patient effort
4. Check alarm time interval and volume setting
References:
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AARC Clinical Practice Guidelines
Basic Clinical Lab Competencies for Respiratory Care, 5th Ed., White
Cardiopulmonary Anatomy & Physiology, Essentials of Respiratory Care, 6th Ed, Des Jardins
Egan’s Fundamentals of Respiratory Care, 10th Ed, Kacmarek, Stoller, Heuer
emedicine.com
Equipment Theory for Respiratory Care, 4th Ed., White
John Hopkins Medical Health Library, hopkinsmedicine.org
MayoClinic.com
Mechanical Ventilation Physiological and Clinical Applications, 5th Ed 2014, Pilbeam
Medline Plus, 2013
Medscape
NCBI, National Center for Biotechnology Information, U.S. National Library of Medicine, 2013
NDNR, Naturopathic Doctor News & Review, 2013
RC Journal
Respiratory Care, Principles & Practice, 2nd Ed, Hess
The Essentials of Respiratory Care, 4th Ed, Kacmarek