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
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
30. Candidates for early tracheotomy:
High levels of sedation
Marginal respiratory mechanics
Psychological benefit
Mobility may assist physical therapy efforts.
30
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
31
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.
Marginal mechanics: in whom a tracheostomy tube having lower resistance might reduce the risk of muscle overload
psychological benefit from the ability to eat orally, communicate by articulated speech, and experience enhanced mobility