troubleshooting and weaning

1. Mechanical ventilation-II
Presenter:
Dr.Tirtha Raj Bhandari
2nd year Resident
NAMS
Moderator:
Consultant Dr.Krishna Bhattarai
KCH,Maharajgunj
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2. Objectives:
 To know common troubleshooting during
mechanical ventilation
 To discuss different troubleshooting
 To discuss management of troubleshooting
 To discuss steps of weaning
 To discuss different weaning criteria
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3. Common Troubleshooting
1) Ventilator alarms
2) Hypoxia(Desaturation)
3) Hypotension
4) Patient ventilator dysynchrony
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4. Assessment
 Is the chest moving and is it moving
symmetrically?
 Is the patient cyanosed?
 What is the arterial saturation?
 Is the patient haemo-dynamically stable?
-Do not forget to observe respiratory pattern and
feature of respiratory distress
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5. High Airway Pressure
Why does this matter??
-Risk of barotrauma
-Hypoventilation(premature termination by high
airway pressure)
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6. Causes of high airway pressure;
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7. CONTD
 Ventilator malfunction/setting
 circuits problems
 Endotracheal tube obstruction
 Increase airway resistance
 Decrease compliance of lung
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8. Dynamic Compliance Static compliance(lung)
Bronchospasm Obesity
Kinking of tubes Atelectasis, ARDS
Airway obstruction(mucus, secretions) Pneumothorax
Retained secretion
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9. Dynamic compliance  PIP
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10. Static Compliance Both PIP and PLAT
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11. Low Airway Pressure/volume
Why it is important??
-Risk of hypoventilation hypoxia and
hypercarbia(Lactic and respiratory acidosis) 
Deasaturation Bradycardia Cardiac Arrest
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13. Auto-peep
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14. Causes of Auto-peep formation
 Inadequate time for expiration, either by flow
limitation or development of resistance in airway
or endotracheal tube
 More time for inspiration
 Obstructive airway disease
 High minute ventilation( High Tidal Volume, High
Frequency)
 Dysynchrony
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15. Pathophysiological Consequences of air
trapping
 Air-trappingDynamic hyperinflation Autopeep
leads following consequences,
1) Increase intra-thoracic pressure
2) Increase work of breathing
3) Decrease preload  Hypotension
4) Worsened V/Q mismatch
5) Increase risk of barotrauma
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19. Management of Auto-PEEP
 Depends upon cause
-decrease MV
-allow sufficient time for expiration
-bronchodilator
-use higher size tube
-remove obstruction in airway
-increase sedation
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20. Desaturation(Hypoxia)
Causes:
 Ventilatory Malfunction
 ET tube disconnection(circuit malfunction), cuff
leak
 Oxygen failure
 Any causes of hypoxic respiratory failure
 Special consideration: endobronchial intubation,
pneumothorax, collapse of part of lung,
pulmonary edema, bronchospasm and pulmonary
embolism
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21. Management
 Increase Fio2 to 1.0
 Check whether the chest is moving or not
 Briefly examine chest to determine the cause of desaturation
 If cause is not obvious manually ventilate the patient with
100% oxygen to exclude ventilator malfunction as the cause
 Treat underlying cause
 Alter ventilator settings to improve oxygenation
 Chest x-ray
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24. Hypotension
Immediately after the initiation of mechanical ventilation
hypotension can occur:
Causes:
 Relative Hypovolaemia: reduction in venous return exacerbated
by positive intra-thoracic pressure.
 Drug induced vasodilation and myocardial depression: all
induction agents have some short lived vaso-dilatory myocardial
depressant effects.
 Tension pneumothorax
 Gas trapping (dyanamic hyperinflation)
Delayed cause may be due to pathological process going on in
patient’s body.
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25. Management
 Depends upon causes
-fluid therapy
-decrease positive pressure/peep
-treat air trapping
-chest tube(if pneumothorax)
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26. Dysynchrony
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27. Dysynchrony
Why it is important??
-increases airway pressure
-air trapping
-increase work of breathing
-hypoventilation
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28. Dysynchrony
According to its relationship to specific phases of the
delivered breath:
 breath initiation/trigger,
 flow delivery and
 breath cycling/termination.
*Asynchrony/dysynchrony index(asynchony/RR) >10%
is significant
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30. Ineffective trigger
Causes: improper setting of sensitivity, weak
patient effort, auto-peep
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31. Auto-trigger
Causes: low trigger sensitivity, circuit leak, water in the circuit, cardiac oscillation.
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32. Double trigger
Causes: unusually high ventilatory demand, low PaO2/FiO2, longer/too short inspiratory time of patient
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33. Flow Dysynchrony
Causes: High respiratory drive, insufficient flow setting
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34. Premature cycling
Causes: Increase neural inspiratory time, earlier termination of inspiration by ventilator34

35. Delayed cycling
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36. Management
 Select the appropriate mode
 Proper trigger setting
 Adjust adequate flow
 Adjust proper cycling
 Clear airway
 Treat auto-peep
 Sedation
 Neuromuscular blockade
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37. WEANING
 Weaning is the process of withdrawing mechanical
ventilatory support and transferring the work of
breathing from the ventilator to the patient.
 In most cases, weaning may be accomplished
rapidly from full ventilatory support to unassisted
spontaneous breathing.
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41. Weaning success
 Weaning success is defined as absence of
ventilatory support 48 hours following the
extubation.
 The spontaneous breaths are unassisted by
mechanical ventilation,
 Supplemental oxygen, bronchodilators, pressure
support ventilation, or continuous positive airway
pressure may be used to support and maintain
adequate spontaneous ventilation and
oxygenation.
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42. Weaning In Progress
 Weaning in progress is an intermediate category
(between weaning success and weaning failure)
for patients who are extubated but continue to
receive ventilatory support by noninvasive
ventilation (NIV)
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43. Weaning Failure
 Weaning failure is defined as either the failure of
spontaneous breathing trial (SBT) or for
reintubation within 48 hours following extubation.
 Patients who fail the SBT often exhibit the
following clinical signs: tachypnea, tachycardia,
hypertension, hypotension, hypoxemia, acidosis,
or arrhythmias.
 Physical signs of SBT failure may include
agitation, distress, diminished mental status,
diaphoresis, and increased work of breathing
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45. CONTD
 Causes of failure are
1) Increase airway resistance
2) Decrease in compliance of lungs
3) Respiratory muscle fatigue
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46. Spontaneous Breathing Trail
 The patient may be discontinued from full ventilatory
support and placed on a spontaneous breathing mode
via the ventilator or T-tube (Brigg’s adaptor) for up to
30 minutes.
 Oxygen and low level pressure support may be used to
supplement oxygenation and augment spontaneous
breathing.
 The criteria for passing an SBT include normal
respiratory pattern (i.e., absence of rapid shallow
breathing), adequate gas exchange, and hemodynamic
stability.
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48. Rapid Shallow Breathing Index(RSBI)
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<100=success of weaning
>100=failure of weaning

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50. ANY QUESTIONS???
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51. Summary
 Mechanical ventilation may encounter lots of
troubleshooting.
 Always first rule out ventilator failure during
troubleshooting by disconnecting it.
 Weaning is gradual process ,it starts from the
time of start of mechanical ventilation to
extubation and success of weaning.
 We should know how to wean and criteria for it,
and factors hindering it.
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52. THANK YOU
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