Weaning from Mechanical
Ventilation and Extubation
1
Objectives
• Identify different methods of titrating support
during weaning
• Factors to consider when weaning
• Identify the recommendations for weaning
developed by the AARC guidelines
• Identify when to abort a SBT
• Identify when a patient is ready for extubation
• Identify and treat post extubation difficulties
2
Objectives
• Identify appropriate strategies, management
and goals when a patient has failed an SBT
3
Methods of Titrating Support
During Weaning
• Support can be reduced as patient’s become
increasingly able to resume part of the work
of breathing
• Three traditional methods:
– SIMV
– PSV
– T piece weaning
• Closed loop ventilation
4
Methods of Titrating Support
During Weaning- SIMV
• SIMV
– Theory underlying is that the patient’s muscles
would work during breaths spontaneous and rest
during mandatory breaths.
– Reduce rate progressively, 1-2 breaths at a time
– PSV from 5-10 can be added- esp. important as
the rate is reduced
– In reality the respiratory muscles perform
significant work in both spontaneous and
mandatory breaths
5
Methods of Titrating Support
During Weaning- PSV
• PSV- patient controls the rate, timing, and
depth of each breath
• Patient triggered, pressure limited, flow cycled
• Set PSV– level that accomplishes a reasonable ventilatory
pattern -usually PSV is 5- 15 cmH2O
– Level that reestablished baseline RR and VT
6
Methods of Titrating Support
During Weaning- PSV
• Gradually reduce PSV as long as RR and Vt is
maintained and pt has no signs of distress
• Once PSV is reduced to 5 cmH2O, PS is just to
overcome work imposed by the ventilator
system
7
Methods of Titrating Support
During Weaning- T - Piece Trial
• Oldest form available
• Advantage to accomplish through the vent –
alarms
• Disadvantage- increased workload
8
Methods of Titrating Support
During Weaning
• No one method is more superior than the
other
• If one method doesn’t‘ work, another may
9
Evaluation of Weaning Attempt
A patient who appears to be ready for discontinuation of ventilatory
support is being weaned with SIMV. The data below indicate the
patient's progress. No PSV or CPAP is used to support spontaneous
breaths.
(Pilbeam and Cairo, Susan P., J.M.. Mechanical Ventilation, 4th
Edition. C.V. Mosby, 022006. p. 446).
10
• 80% of patients do not require a slow
withdrawal process and can be removed
within a few hours or days from support.
– Post Op
– Drug Overdose
– Exacerbations of Asthma
11
Factors to consider
• Some will require support during weaning
• O2 and Peep
• Some may require artificial airway after vent is
withdrawn
• Some need all of the above
12
Where does all this rational come
from?
1999-The Federal Agency for Healthcare Policy and
Research asked the McMaster University Outcomes
Research Unit to perform comprehensive review of
literature on ventilator withdrawal.
Task force used this review to create evidence-based
guidelines for weaning for patients that require more
than 24 hours of ventilator support.
AARC and Resp. Care Journal 2002.
13
What is the first thing that we need to consider
before we begin weaning attempts?
a.
b.
c.
d.
FiO2
Rate
Whether the underlying problem is resolved
None of the above
14
Recommendation 1.
In patients requiring mechanical ventilation for > 24
hours, a search for all the causes that may be
contributing to ventilator dependence should be
undertaken.
This is particularly true in the patient who has failed
attempts at withdrawing the mechanical ventilator.
Reversing all possible ventilatory and nonventilatory
issues should be an integral part of the ventilator
discontinuation process.
15
Is the Respiratory Failure Resolved?
•
•
•
•
•
Neurological
Respiratory Factors
Metabolic and Ventilatory Muscle Function
Cardiovascular Factors
Psychological Factors
Even if the patient’s disease that led to
ventilation has improved or reversed,
still need to consider overall condition
16
Recommendation 2.
Patients receiving mechanical ventilation for respiratory failure should
undergo a formal assessment of discontinuation potential if the following
criteria are satisfied:
• Evidence for some reversal of the underlying cause of respiratory failure;
• Adequate oxygenation .requiring positive end-expiratory pressure [PEEP] <
8 cm H2O; FIO2 < 0.5) and pH (eg, > or = 7.25);
• Hemodynamic stability
• The capability to initiate an inspiratory effort.
• Sedation vacation
• GCS >8
• Afebrile
17
Criteria
•
•
•
•
•
•
•
•
PEEP < or = 8 cm H2O;
FIO2 < or = 0.5
pH > or = 7.25
Hemodynamic stability
The capability to initiate an inspiratory effort.
Sedation vacation
GCS >8
Afebrile
Although these tell us about potential for
a successful discontinuation, assessments
made during a 30-120 minute SBT may be
the most useful guide for making a
decision about discontinuation
18
Weaning criteria
• Stable, spontaneously breathing and alert.
• 75% of patients who meet criteria tolerate an
initial trial of SBT
• 30% who never satisfy criteria are successfully
weaned
• No single measure has been established that
is uniformly successful in predicting a patient’s
“weanability.”
19
Recommendation 3.
• Formal discontinuation assessments should be done during
spontaneous breathing rather than while the patient is still
receiving substantial ventilatory support.
• An initial brief period of spontaneous breathing should be
used to assess the capability of continuing onto a formal SBT.
• During the SBT assess the patient’s respiratory pattern,
adequacy of gas exchange, hemodynamic stability, and
subjective comfort.
• The tolerance of SBTs lasting 30 to 120 minutes should
prompt consideration for permanent ventilator
discontinuation.
20
Weaning criteria- During SBT
• Muscle strength
–
–
–
–
VC >15ml/kg or > 1.0 lpm
Ve <10 l/min
TV > 250 or = 5-8 ml/kg
f 8-20
• Dependant on patients disease process
– Ventilatory pattern is synchronous and stable
– NIF = -20 or greater
– RSBI = <105 (f/VT)
77%-85% of patients who pass an SBT
can beweaned and extubated without
requiring reintubation
21
SBT
• SBT lasts at least 30 minutes but not more
than 120 minutes
• low level of CPAP – e.g. 5 cm H2O
• Low level PSV- e.g. 5-8 cm H2O
• T piece
• Auto Tube Compensation
• All provide good results
22
Signs that patient is failing SBT
• RR > 30-35 BPM (also watch for change greater than 10BPM or decrease
to below 8)
• VT < 250 mL (5- ml/kg)
• Significant BP changes
• HR increases 20% or exceeds 140 BP
• Sudden onset PVC’s (more than 4-6 per minute)
• Diaphoresis
• Clinical signs- such as deteriorating ABG’s or saturations
23
You should consider ending an SBT under which of the following
circumstances?
A. The RR increases from 20 to 25 breaths per min
B. The Vt decreases from 350 mL to 150 mL
C. The systolic blood pressure decreases from 150 to 140 mm Hg
D. The heart rate increases from 90 to 100 beats per min
24
Recommendation 4.
• The removal of the artificial airway from a patient
who has successfully been discontinued from
ventilatory support should be based on assessments
of airway patency and the ability of the patient to
protect the airway.
25
Removal of Airway
• Asses airway patency and ability to protect airway
• Risks:
– Aspiration
– Inability to clear secretions
– Unsuccessful Cuff Leak Test
• Successful leak test does not guarantee that post-extubation
difficulties will not arise.
• 80% of patients that intentionally self-extubate do no need to
be re intubated
26
Cuff Leak Test
• To qualify- the patient must no longer NEED
Ventilatory support
– Cuff is deflated
– A leak around the cuff during spontaneous
breathing suggests that the airway is adequate
and successful extubation is likely.
27
NiPPV
• Beneficial for those who need some degree of support
• Helps ease the transition from invasive ventilation to
spontaneous breathing
• Benefits:
– Improves survival
– Lowers Mortality rate
– Reduces risk of nosocomial pneumonia
– Shortens ICU and hospital stays
28
Criteria for NiPPV
• Resolutions of problems leading to Respiratory
Failure
• Ability to tolerate SBT for 10-15 minutes
• Strong cough reflex
• Hemodynamic Stability
• Minimal Secretions
• Low O2 requirements
• Optimum nutrition status
Patient cooperation is key to success
29
Failed Weaning Attempt
A 76-year-old man with a history of COPD has been
on ventilatory support for 4 days, since he had a heart
attack. The ventilator settings are:
Vt = 700 mL; SIMV
rate = 8 breaths/min; FIO2 = 0.5; PEEP/CPAP = 5 cm
H2O. ABG results on these settings are: pH = 7.37;
PaCO2 = 36 mm Hg; PaO2 = 78 mm Hg; SpO2 = 93%.
The patient currently meets all criteria for weaning and
is placed on a T-piece. Within 10 minutes he develops
restlessness, tachycardia, rapid, shallow breathing,
and diaphoresis. The SpO2 drops from 93% to 90%,
and the pulmonary artery wedge pressure rises from 12 to
17 mm Hg. The patient does not complain of chest pain
and has no dysrhythmias.
What do you think is responsible for the failed weaning
attempt?
(Pilbeam and Cairo, Susan P., J.M.. Mechanical
Ventilation, 4th Edition. C.V. Mosby, 022006. p. 463).
30
Weaning
Failure
31
Recommendation 5.
• Patients receiving mechanical ventilation for
respiratory failure who fail an SBT should have
the cause for the failed SBT determined. Once
reversible causes for failure are corrected, and
if the patient still meets the criteria listed in
Table 3, subsequent SBTs should be performed
every 24 hours.
32
Factors in Weaning Failure
SBT should be performed every 24 hours once:
1. Reversible causes have been corrected AND
2. Patient still meets criteria for discontinuation
Avoid pushing patient to point of
exhaustion as it will only delay
success
33
Factors in Weaning Failure, cont’d
• Other causes of or complications
– Inadequate pain control
– Inappropriate sedation
– Impaired fluid status
– Need for Bronchodilator Therapy
– Other disease processes (i.e., MI)
34
Factors in Weaning Failure, cont’d
• Non- Respiratory Factors that may complicate
weaning:
– Cardiac Factors
– Acid- Base Factors
– Metabolic
– Pharmacological Agents
– Nutritional Status
– Psychological Factors
(See Table 20-2 on page 461.)
35
Recommendation 6.
• Patients receiving mechanical ventilation for
respiratory failure who fail an SBT should
receive a stable, nonfatiguing, comfortable
form of ventilatory support.
36
Maintain ventilation after SBT
failure
–
Clinical focus for the 24 hours after a failed
SBT is:
1. maintain adequate muscle unloading
2. optimizing comfort (sedation)
3. preventing complications
4. patient load needs to be non fatiguing
Do not focus on aggressive ventilatory
support reduction
37
Maintain ventilation after SBT
failure, cont’d
• When patient fails SBT, repeated testing the same day is no
benefit
• No evidence to support that gradual reduction strategy is
better than providing full, stable support between once daily
SBT’s
• One finding of the task force was how poorly clinicians assess
the potential for ventilator discontinuation, esp in patients
considered ventilator dependent for longer than several days.
• This emphasizes the need for more focused assessment
strategies
38
The clinical focus for the 24 hours after a failed SBT should concentrate on all
of the following EXCEPT:
A. Optimizing Comfort
B. Continuing to try and reduce ventilatory support
C. Preventing Complications
D. Maintain stable ventilation and not allow patient to fatigue
39
Recommendation 7.
• Anesthesia/sedation strategies and ventilator
management aimed at early extubation
should be used in postsurgical patients.
40
Early extubation in post op patients
1. Focus needs to be early extubation in post-op
patients
2. Ventilated primarily because of depressed
respiratory drive and pain
Due to the unreliable respiratory drive, utilize modes that
guarantee a breathing rate and Ve.
41
Recommendation 8.
• Weaning/discontinuation protocols designed
for nonphysician health care professionals
(HCPs) should be developed and implemented
by ICUs. Protocols aimed at optimizing
sedation should also be developed and
implemented.
42
Weaning protocols
• Development and implementation of therapist driven
protocols (TDP’s) in ICU’s
• TDP’s have been found to be safe and to reduce hospital costs
by shortening the time required for ventilatory support
• Significant drop in extubation failures and
shorter weaning times when TDPs’ are used.
• Studies suggest that physicians are way too
Conservative when considering whether a
patient is ready for SBT or extubation
43
44
All of the following are true for TDP protocols EXCEPT
A. They shorten weaning time
B. They significantly reduce extubation times
C. Physicians are aggressive in starting SBT’s
D. They are less costly than conventional weaning techniques
45
Recommendation 9.
• Tracheostomy should be considered after an
initial period of stabilization on the ventilator
when it becomes apparent that the patient
will require prolonged ventilator assistance.
Tracheotomy should then be performed when
the patient appears likely to gain one or more
of the benefits ascribed to the procedure.
46
Tracheostomy’s
Patients who may derive particular benefit from early tracheotomy are the
following:
1. Patients need high levels of sedation to tolerate ET tubes
2. Patients have marginal respiratory efforts (often manifested as
tachypnea) – a trach tube has lower resistance which can help reduce the
WOB
3. Patients who will benefit from the ability to eat orally,
enhanced communication (Speech), and
have enhanced mobility; and
4. Patients in whom enhanced mobility may assist
physical therapy efforts
47
Tracheostomy’s cont’d
• Patients have less facial discomfort
• Reduced WOB, deadspace and better secretion
removal
48
Tracheotomy is most indicated for which of the following patients
A. Those requiring low levels of sedation to tolerate ET
B. Those with strong respiratory mechanics who rarely exhibit
tachypnea
C. Those who may gain psychological benefit from the ability to eat, talk
and have greater mobility
D. Those with good mobility and easy tolerance of physical therapy
efforts
49
Recommendation 10.
Unless there is evidence for clearly irreversible
disease (eg, high spinal cord injury or
advanced amyotrophic lateral sclerosis), a
patient requiring prolonged mechanical
ventilatory support for respiratory failure
should not be considered permanently
ventilatordependent until 3 months of
weaning attempts have failed.
50
Ventilator Dependence
Unless there is evidence of
Irreversible disease (ALS, paralysis,
etc.) a patient should not be
considered “ventilator dependent”
until 3 months have passed and all weaning
attempts have failed.
51
Recommendation 11
• RT’s should be familiar with facilities in their communities, or
units in hospitals they staff, that specialize in managing
patients who are vent dependent
• When medically stable for transfer, patients who have failed
ventilator discontinuation attempts in the ICU should be
transferred to those facilities that have shown that they are
successful in accomplishing ventilator discontinuation.
52
Recommendation 12.
• Weaning strategy in the long term patient
should be slow-paced and should include
gradually lengthening self-breathing trials.
53
Weaning the long term patient in
long term facilities
1. Reduce amount of support
2. Reduce invasiveness of support
3. Increase independence
4. Preserve or improve current
function
5. Maintain medical stability
Protocols are usually individualized rather than fixed
like in ICU.
54
Weaning the long term patient in
long term facilities, cont’d.
• Weaning is slow
• Daily SBT’s are not performed because patients
won’t be weaned successfully in 24 hours
55