The document discusses various methods for weaning patients off mechanical ventilation, including SIMV, T-piece trials, CPAP/BiPAP, and pressure support. It notes major factors to consider for each patient such as their primary illness, ventilatory support needs, and other medical conditions. Key criteria for determining readiness for weaning trials and extubation include respiratory rate, vital capacity, gas exchange values, hemodynamic stability, and underlying disease improvement. Factors that could lead to weaning or extubation failure are also outlined.

1. Dr Sangita Agale
Assistant professor
Anaesthesia department
VDGIMS,LATUR

3. Before titration is begun, the method for weaning
should be considered. Titration should be patient
specific, taking into consideration the patient's
primary illness, length of ventilatory support, and
other confounding medical conditions. Four
major modes of titration are commonly used:
1. SIMV
2. T-piece
3. CPAP / BiPAP
4. Pressure Support

4.  T-piece trials are usually used with resting periods
of assist control (AC) ventilation. The advantage to
this approach is that while weaning the patient is
doing all the work of breathing, and while on AC
the patient is allowed to rest.
 AC with T-piece trials may work best in the patient
with COPD or other chronic lung conditions that
cause respiratory muscle weakness.

5.  Synchronized intermittent mandatory ventilation
(SIMV) is most useful in patients whom a rapid
change in intrathoracic pressure would cause
hemodynamic instability.
 Patients with cardiovascular disease can suffer
from congestive failure due to increased venous
return that occurs with rapid changes in thoracic
pressure.
 SIMV allows for gradual change from positive
pressure ventilation to spontaneous (negative)
pressure ventilation.

6.  Continuous positive airway pressure (CPAP) and
bi-level positive airway pressure (BiPAP) are
effective in providing expiratory support to
maintain oxygenation and prevent alveolar
collapse during titration.
 They also maintain a level of positive intrathoracic
pressure that may be helpful in the cardiovascular
patient.
 BiPAP adds inspiratory support to CPAP, which may
be helpful in preventing respiratory muscle
fatigue.

7.  Pressure support (PS) provides inspiratory support
to help overcome airway resistance and decrease
respiratory muscle fatigue.
 PS may be helpful in retraining respiratory muscles
in a patient who has been on long-term
ventilation.

8.  Usually sedation is discontinued when weaning is
begun. This often results in a wide-awake,
frightened patient who is "bucking" the ventilator
and pulling on the tube.
 Most patients say that mechanical ventilation is
extremely uncomfortable, and moderately painful.
Therefore, it would make sense to manage the
patient's pain and discomfort for the best
outcome.
 Include sedation, pain control, and anxiety control
in modest amounts to keep the patient
comfortable but conscious during weaning.

9.  Once the previous planning has been done, Check
the patient's nutritional status.
 Assure adequate rest the night before weaning.
 Shortly before weaning, suction the patient and
allow several minutes for his oxygenation to
return to normal. Using 100% FiO2 during
suctioning helps to accomplish this

10.  Start the weaning trial at the appropriate time of
day.
 Mornings can be difficult for several reasons:
1. Preload may be higher in the morning
2. Respiratory function is worse in the morning
(circadian effects)
3. Interruptions are more frequent (rounds, shift
change, etc.)

11.  Determination of assessment parameters for continued
weaning (Go), cautious weaning (Caution), weaning
discontinuation (Stop) should be made before the trial is
begun.Some general guidelines are below:
1. Go:
 No respiratory distress
 Hemodynamically stable
2. Caution:
 Mild respiratory distress
 Hemodynamic changes
3. Stop:
 Respiratory distress, respiratory acidosis
 Vital sign changes: increased RR, HR, B/P

12.  RR<30
 VC>15ML/KG
 Rapid shallow breathing index(RR/TV)>100
 Max inspiratory force>-20cm h20
 VD/VT<0.6
 Pao2>80 with fio2 0.4
 Paco2<45
 Ph>7.3
 PAo2-Pao2<300 on Fio2 1
 Qs/Qt<15%
 Conscious pt
 Cardiovascular stability
 Metabolically stable
 Underlying disease process should have improved

13.  The Cuff leak test during MV:
 Set a tidal Volume 10-12 ml/kg
 Measure the expired tidal volume
 Deflated the cuff
 Remeasure expired tidal volume (average of 4-6 breaths)
 The difference in the tidal volumes with the cuff inflated
and deflated is the leak
 A value of 130ml  85% sensitivity
95% specificity
Extubation Criteria

14.  Cough / Leak test in spontaneous breathing
 Tracheal cuff is deflated and monitored for the first 30
seconds for cough.
 Only cough associated with respiratory gurgling (heard
without a stethoscope and related to secretions) is taken
into account.
 The tube is then obstructed with a finger while the patient
continues to breath.
 The ability to breathe around the tube is assessed by the
auscultation of a respiratory flow.
Extubation Criteria

15. Daily SBT
<100
Mechanical Ventilation
RR > 35/min
Spo2 < 90%
HR > 140/min
Sustained 20% increase in HR
SBP > 180 mm Hg, DBP > 90 mm Hg
Anxiety
Diaphoresis
30-120 min
PaO2/FiO2 ≥ 200 mm Hg
PEEP ≤ 5 cm H2O
Intact airway reflexes
No need for continuous infusions of vasopressors or inotrops
RSBI
Extubation
No
> 100
Rest 24 hrs
Yes
Stable Support Strategy
Assisted/PSV
24 hours
Low level CPAP (5 cm H2O),
Low levels of pressure support (5 to 7 cm H2O)
“T-piece” breathing

16.  Gas flow to the inspiratory limb should be atleast
twice that of pt. minute ventilation in order to
meet pt peak respiratory rate
 An extension piece of at least 12 inches should be
added to expiratory limb to prevent entrainment
of room air
 If a patient is comfortable without signs of
detioration of gaseous exchange for 2 hrs , pt can
be safely extubated

17.  Increase in RR by > 10 breath/min or to > 40
breath/min
 Increase or decrease in BP by >20mmhg
 Increase or decrease in HR by >20 beat/min
 SaO2 <90% or PaO2<60mmhg
 Increase in PaCO2>5mmhg and/or decrease in
Ph<7.3
 Development of cardiac arrythmias
 Signs of increased work of breathing(e.g. accessory
muscle use, nasal flaring, intercostal recession,
paradoxical respiration
 Diaphoresis, complaints of dyspnoa, fatigue or pain
not relieved by reassurance
 Detoriation of ABG is a late indication

18. Failure of SBT
Increased resistance
Decreased compliance
Increased WOB and exhaustion
Auto-PEEP
Respiratory
Backward failure: LV dysfunction
Forward heart failure
Cardiovascular
Poor nutritional status
Overfeeding
Decreased Mg and PO4 levels
Metabolic and respiratory alkalosis
Metablic/Electrolytes
Infection/fever
Major organ failure
Stridor

19.  Start with 80% of RR of A/C
 Reduce SIMV rate in steps of 1-3 breath/min at each
step
 Moniter pt clinically and do the ABG
 If Ph >7.3 reduce the rate further in steps of 1-3
breath/min
 Reduce till a rate of 2-4 breath/min is reached
 If deterioration develops in any step, increase the
SIMV rate again
 Extubate the pt
 Allow the pt muscle to rest at night by increasing the
SIMV rate

20.  Set SIMV rate 2 breath/min less then in A/C plus
PSV15-20 cm H20
 Reduce SIMV rate in steps of 1-3 breath/min plus
PSV 15-20cm h20
 When SIMV reaches 2-4 breath/min, stop SIMV and
continue with PSV 15-20 cm H20
 Reduce PSV in steps of 2cm H20 until PSV until PSV
is 5-6 cm H20
 Extubate the pt.
 If deterioration develops in any step, increase the
SIMV/PSV rate again
 Allow the pt muscle to rest at night by increasing the
PSV rate

21.  Start with PSV 15-20 cm H20
 Reduce PSV in steps of 2cm H20 until PSV until
PSV is 5-6 cm H20
 Extubate the pt.
 If deterioration develops in any step, increase the
PSV rate again
 Allow the pt muscle to rest at night by increasing
the PSV rate

22.  RR<30
 VC>15ml/kg
 PAO2>60 on fio2<0.5
 Paco2<50
 Ph>7.3
 SIMV~1-2 breath/min
 Conscious pt
 Cardiovascular stability
 Metabolically stable

23.  It is defined as a need of reintubation within 7
days
 Predisposing conditions
1. Increased resistive loads
2. Increased chest wall elastic loads
3. Increased lung elastic loads
4. Decreased drive
5. Muscle weakness
6. Impaired neuromuscular transmission

24. 1. Bronchospasm
2. Airway edema, secretions
3. Upper airway obstruction
4. Obstructive sleep apnea
5. Endotracheal tube kinking
6. Secretions encrustation
7. Ventilatory circuit resistance

25.  Pleural effusion
 Pneumothorax
 Flial chest
 Obesity
 Ascitis
 Abdominal distension

26.  Hyperinflation
 Alveolar edema
 Infection
 atelectasis

27.  Drug overdose
 Brain stem lesion
 Sleep deprivation
 Hypothyroidism
 Starvation
 Metabolic alkalosis
 Myotonic dystrophy

28.  Electrolyte imbalance
 Myopathy
 Malnutrition
 steroids

29.  Critical illness polyneuropathy
 Neuromuscular blockers
 Aminoglycosides
 Guillain-Barré syndrome
 Mysthenia gravis
 Phrenic nerve injury
 Spinal cord lesion

30.  Candidates for early tracheotomy:
 High levels of sedation
 Marginal respiratory mechanics
 Psychological benefit
 Mobility may assist physical therapy efforts.
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31.  The benefits of tracheotomy include:
 improved patient comfort
 more effective airway suctioning
 decreased airway resistance
 enhanced patient mobility
 increased opportunities for articulated speech
 ability to eat orally, and
 more secure airway
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32.  Patient at high risk of extubation failure who have
passed SBT, transition to NIV has reduced ICU stay
and short and long term mortality.
 Initial SBT be conducted with inspiratory pressure
augmentation rather than T piece or CPAP was
associated with lower ICU mortality.
 Cuff leak test should be used only in patient with
high risk of stridor.
 Patients who failed cuff leak test but are otherwise
ready for extubation, systemic steroid 4 hr before
extubation should be used.

33. Thank
you