1. Weaning Modes and Protocol

2. Causes of Ventilator Dependence Assessment for Discontinuation Trial
Spontaneous Breathing Trial (SBT)
Extubation Criteria
Failure of SBT
Weaning Modes
Weaning Protocols
Role of Tracheostomy
Long-term Facilities

3. Stages of Mechanical Ventilation
The six stages are defined in table 1 and are as follows: 1) treatment of acute respiratory failure (ARF); 2) suspicion that weaning may be possible; 3) assessment of readiness to wean; 4) spontaneous breathing trial (SBT); 5) extubation; and possibly 6) reintuba-tion.
weaning process represents 40–50% of the total duration of mechanical ventilation 2

4. Causes of Ventilator Dependence
Who is the “ventilator dependent’?
Mechanical ventilation > 24 h or
Failure to respond during discontinuation attemps
In patients requiring mechanical ventilation for 24 h, 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.

5. Causes of Ventilator Dependence
Description
Causes
Central drive
Peripheral nerves
Neurologic controller
Mechanical loads
Ventilatory muscle properties
Gas exchange properties
Respiratory system
Cardiac tolerance of ventilatory muscle work
peripheral oxygen demands
Cardiovascular system
Psychological issues
Ventilatory muscle properties: inherent strength/endurance; metabolic state/nutrients/oxygen delivery and extraction
Gas exchange properties: vascular properties and ventilation/perfusion matching

6. Assessment for Discontinuation Trial
Criteria for discontinuation trial:
Evidence for some reversal of the underlying cause for respiratory failure
Adequate oxygenation and pH
Hemodynamic stability; and
The capability to initiate an inspiratory effort
Oxegenation: (eg, PaO2/Fio2 ratio 150 to 200; requiring positive end-expiratory pressure [PEEP] 5 to 8 cmH2O; Fio to 0.5)
pH (eg, 7.25);
, hemodynamic stability is defined by the absence of active myocardial ischemia and the absence of clinically significant hypotension (ie, a condition requiring no vasopressor therapy or therapy with only low-dose vasopressors such as dopamine or dobutamine, 5 g/kg/min)

7. Assessment for Discontinuation Trial
Extubation failure
8-fold higher odds ratio for nosocomial pneumonia
6-fold to 12-fold increased mortality risk
Reported reintubation rates range from 4 to 23% for different ICU populations

8. Assessment for Discontinuation Trial
Criteria Used in Weaning/Discontinuation in different studies

9. Assessment for Discontinuation Trial
Measurements used To Predict the Outcome of a Ventilator Discontinuation Effort in More Than One Study

10. Spontaneous Breathing Trial
Formal discontinuation assessments should be performed during spontaneous breathing
An initial brief period of spontaneous breathing can be used to assess the capability of continuing onto a formal SBT.
the initial few minutes of an SBT should be monitored closely before a decision is made to continue (this is often referred to as the “screening”
phase of an SBT)
CPAP, however, conceivably could enhance breath triggering in patients with significant auto-PEEP

11. Spontaneous Breathing Trial
How to assess patient tolerance?
the respiratory pattern
the adequacy of gas exchange
hemodynamic stability, and
subjective comfort.

12. Criteria Used in Several Large Trials To Define Tolerance of an SBT*
Spontaneous Breathing Trial
Criteria Used in Several Large Trials To Define Tolerance of an SBT*
*HR heart rate; Spo2 hemoglobin oxygen saturation.

13. Spontaneous Breathing Trial
The tolerance of SBTs lasting 30 to 120 min should prompt consideration for permanent ventilator discontinuation

14. Spontaneous Breathing Trial
Frequency of Tolerating an SBT in Selected Patients and Rate of Permanent Ventilator Discontinuation Following a Successful SBT*
*Values given as No. (%). Pts patients.
†30-min SBT.
‡120-min SBT.

15. Do Not Wean To Exhaustion

16. Weaning to Exhaustion RR > 35/min Spo2 < 90% HR > 140/min
Sustained 20% increase in HR
SBP > 180 mm Hg, DBP > 90 mm Hg
Anxiety
Diaphoresis

17. Mechanical Ventilation
> 100
Rest 24 hrs
PaO2/FiO2 ≥ 200 mm Hg
PEEP ≤ 5 cm H2O
Intact airway reflexes
No need for continuous infusions of vasopressors or inotrops
RSBI
Daily SBT
<100
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
RR > 35/min
Spo2 < 90%
HR > 140/min
Sustained 20% increase in HR
SBP > 180 mm Hg, DBP > 90 mm Hg
Anxiety
Diaphoresis
min
Other causes of failure next slide
Extubation No

18. Extubation Criteria Ability to protect upper airway
Effective cough
Alertness
Improving clinical condition
Adequate lumen of trachea and larynx
“Leak test” to identify patients who are at risk for post-extubation stridor

19. Post Extubation Stridor
Extubation Criteria
Post Extubation Stridor
The Cuff leak test during MV:
Set a tidal Volume 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

20. Post Extubation Stridor
Extubation Criteria
Post Extubation Stridor
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.

21. Extubation Criteria
The risk of postextubation upper airway obstruction increases with
the duration of mechanical ventilation
female gender
trauma, and
Repeated or traumatic intubation

22. Failure of SBT Correct reversible causes for failure
adequacy of pain control
the appropriateness of sedation
fluid status
bronchodilator needs
the control of myocardial ischemia, and
the presence of other disease processes
Subsequent SBTs should be performed every 24 h
if the patient still meets the criteria for SBT
strong evidence that twice-daily SBTs offer no advantage over a single SBT and, thus, would serve only to consume unnecessary clinical resources

23. 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 :

24. Failure of SBT Left Heart Failure:
Increased metabolic demands
Increases in venous return and pulmonary edema
Appropriate management of cardiovascular status is necessary before weaning will be successful

25. Failure of SBT
Factors affecting ventilator demands

26. Failure of SBT
Therapeutic measures to enhance weaning progress

27. Weaning Modes
Patients receiving mechanical ventilation for respiratory failure who fail an SBT should receive a stable, nonfatiguing, comfortable form of ventilatory support

28. Modes of Partial Ventilator Support
Weaning Modes
Modes of Partial Ventilator Support
*SIMV synchronized intermittent mandatory ventilation; PSV pressure support ventilation; VS volume support; VAPS(PA) volume assured pressure support (pressure augmentation); MMV mandatory minute ventilation; APRV airway pressure release ventilation.

29. Weaning Modes PSV: Pressure Support
Gradual decrease in the level of PSV on regular basis (hours or days) to minimum level of 5-8 cm H2O
PSV that prevents activation of accessory muscles
Once the patient is capable of maintaining the target ventilatory pattern and gas exchange at this level, MV is discontinued

30. Weaning Modes SIMV: synchronized intermittent mandatory ventilation
Gradual decrease in mandatory breaths
It may be applied with PSV
Has the worst weaning outcomes in clinical trials
Its use is not recommended

31. Weaning Modes New Modes VS, Volume support Automode
MMV, mandatory minute ventilation
ATC, automatic tube compensation
ASV, adaptive support ventilation
Because none of these studies offer evidence that gradual support strategies are superior to stable support strategies between SBTs, the
clinical focus for the 24 h after a failed SBT should be on maintaining adequate muscle unloading, optimizing comfort (and thus sedation needs), and avoiding complications, rather than aggressive ventilatory support reduction
NPPV is recently used to facilitate the discontinuation

32. Weaning Protocols
With the assisted modes, to achieve patient comfort and minimize imposed loads, we should consider:
sensitive/responsive ventilator-triggering systems
applied PEEP in the presence of a triggering threshold load from auto-PEEP
flow patterns matched to patient demand, and
appropriate ventilator cycling to avoid air trapping are all important to

33. Weaning Protocols Weaning protocols
Developed by multidisciplinary team
Implemented by respiratory therapists and nurses to make clinical decisions
Results in shorter weaning times and shorter length of mechanical ventilation than physician-directed weaning
Sedation protocols should be developed and implemented
two-step protocol driven by HCPs using a daily screening procedure followed by an SBT in those who met the screening criteria
In the context of emerging data about the benefits of NPPV and the substantial roles of HCPs in providing this treatment, there should be efforts made to develop HCP-driven protocols for this modality
not be used to replace clinical judgment, but rather to complement it.
Dynamic tool can be modefied
institutions must be prepared to commit the necessary resources to develop and implement protocols. For instance, adequate staffing

34. Role of Tracheotomy Candidates for early tracheotomy:
High levels of sedation
Marginal respiratory mechanics
Psychological benefit
Mobility may assist physical therapy efforts.
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

35. Role of Tracheotomy 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

36. Role of Tracheotomy Concerns: Risk associated with the procedure
Long term airway injury
Costs
Presently, no data support the competing contentions that early tracheotomy either decreases or increases the risk of ventilator-associated pneumonia
More recent studies, however, have established that standard surgical tracheotomy can be performed with an acceptably low risk of perioperative complications
the risk of tracheal stenosis after tracheotomy is not clearly higher than the risks of subglottic stenosis from prolonged translaryngeal intubation
the cost of tracheotomy can be lowered if it is performed in the ICU
Even when tracheotomy is performed in an operating room, the cost may be balanced by cost savings if a ventilator-dependent patient can be moved from an ICU setting after the placement of a tracheostomy

37. Long-term Facilities
Unless there is evidence for clearly irreversible disease (e.g., high spinal cord injury or advanced amyotrophic lateral sclerosis), a patient requiring prolonged mechanical ventilatory (PMV) support for respiratory failure should not be considered permanently ventilator-dependent until 3 months of weaning attempts have failed.

38. Long-term Facilities
Critical-care practitioners should familiarize themselves with specialized facilities in managing patients who require prolonged mechanical ventilation
Patients who failed ventilator discontinuation attempts in the ICU should be transferred to those facilities

39. Long-term Facilities
Weaning strategies in the PMV patient should be slow-paced and should include gradually lengthening SBTs
Psychological support and careful avoidance of unnecessary muscle overload is important for these types of patients
ICU patients receiving PMV can be discontinued effectively and safely from ventilation when they are transferred to units dedicated to that activity

40. Thank You

41. Introduction
75% of mechanically ventilated patients are easy to be weaned off the ventilator with simple process
10-15% of patients require a use of a weaning protocol over a hours
5-10% require a gradual weaning over longer time
1% of patients become chronically dependent on MV

42. Readiness To Wean Improvement of respiratory failure
Absence of major organ system failure
Appropriate level of oxygenation
Adequate ventilatory status
Intact airway protective mechanism (needed for extubation)

43. Oxygenation Status
PaO2 ≥ 60 mm Hg
FiO2 ≤ 0.40
PEEP ≤ 5 cm H2O

44. Ventilation Status
Intact ventilatory drive: ability to control their own level of ventilation
Respiratory rate < 30
Minute ventilation of < 12 L to maintain PaCO2 in normal range
Functional respiratory muscles

45. Intact Airway Protective Mechanism
Appropriate level of consciousness
Cooperation
Intact cough reflex
Intact gag reflex
Functional respiratory muscles with ability to support a strong and effective cough

46. Function of Other Organ Systems
Optimized cardiovascular function
Arrhythmias
Fluid overload
Myocardial contractility
Body temperature
1◦ degree increases CO2 production and O2 consumption by 5%
Normal electrolytes
Potassium, magnesium, phosphate and calcium
Adequate nutritional status
Under- or over-feeding
Optimized renal, Acid-base, liver and GI functions

47. Predictors of Weaning Outcome
Value
Evaluation of ventilatory drive:
P 0.1
< 6 cm H2O
Ventilatory muscle capability:
Vital capacity
Maximum inspiratory pressure
> 10 mL/kg
< -30 cm H2O
Ventilatory performance
Minute ventilation
Maximum voluntary ventilation
Rapid shallow breathing index
Respiratory rate
< 10 L/min
> 3 times VE
< 105
< 30 /min

48. Maximal Inspiratory Pressure
Pmax: Excellent negative predictive value if less than –20 (in one study 100% failure to wean at this value)
An acceptable Pmax however has a poor positive predictive value (40% failure to wean in this study with a Pmax more than –20)

49. Frequency/Volume Ratio
Index of rapid and shallow breathing RR/Vt
Single study results:
RR/Vt> % wean attempts unsuccessful
RR/Vt< % successful
One of the most predictive bedside parameters.

50. Measurements Performed Either While Patient Was Receiving Ventilatory Support or During a Brief Period of Spontaneous Breathing That Have Been Shown to Have Statistically Significant LRs To Predict the Outcome of a Ventilator Discontinuation Effort in More Than One Study*

51. Weaning to Exhaustion RR > 35/min Spo2 < 90% HR > 140/min
Sustained 20% increase in HR
SBP > 180 mm Hg, DBP > 90 mm Hg
Anxiety
Diaphoresis

52. Work-of-Breathing High airway resistance Low compliance
Pressure= Volume/compliance+ flow X resistance
High airway resistance
Low compliance
Aerosolized bronchodilators, bronchial hygiene and normalized fluid balance assist in normalizing compliance, resistance and work-of-breathing

53. Auto-PEEP Increases the pressure gradient needed to inspire
Use of CPAP is needed to balance alveolar pressure with the ventilator circuit pressure
Start at 5 cm H2O, adjust to decrease patient stress
Inspiratory changes in esophageal pressure can be used to titrate CPAP

54. Gradient -5 -5

55. Gradient
Auto PEEP +10 -5
-15

56. PEEP 10
Gradient
Auto PEEP +10 5 -5

57. Preparation: Factors Affecting Ventilatory Demand

59. The frequency to tidal volume ratio (or rapid shallow breathing index, RSBI) is a simple and useful integrative indicator of the balance between power supply and power demand. A rapid shallow breathing index < 100 generally indicates adequate power reserve. In this instance, the RSBI indicated that spontaneous breathing without pressure support was not tolerable, likely due in part to the development of gas trapping.
Even when the mechanical requirements of the respiratory system can be met by adequate ventilation reserve, congestive heart failure, arrhythmia or ischemia may cause failure of spontaneous breathing.

60. Integrative Indices Predicting Success

61. Measured Indices Must Be Combined With Clinical Observations

62. Three Methods for Gradually Withdrawing Ventilator Support
Although the majority of patients do not require gradual withdrawal of ventilation, those that do tend to do better with graded pressure supported weaning than with abrupt transitions from Assist/Control to CPAP or with SIMV used with only minimal pressure support.

63. Thank You