Dr. Sujay Halkur Shankar presented on the topic of weaning patients from mechanical ventilation. The presentation covered assessing patient readiness, different weaning methods like spontaneous breathing trials, factors that can cause difficulty weaning like respiratory, cardiac and neuromuscular issues, and post-extubation care. Spontaneous breathing trials are the preferred method of weaning and have higher rates of success than pressure support or intermittent mandatory ventilation. Factors that can contribute to weaning failure include increased respiratory load or drive, decreased respiratory muscle strength, and cardiac dysfunction induced by weaning.

1. Presenter: Dr. Sujay Halkur Shankar
Resident Preceptor: Dr. Gogineni Ratnakar
Faculty Preceptors: Dr. Ved Prakash Meena
Dr. Animesh Ray
Dr. Manish Soneja
Weaning
The art and science

2. Learning Objectives
• Assess for the readiness for weaning
• Understand the popular methods of weaning
• Learn the approach to a patient difficult to wean

3. Topic Outline
• Introduction
• Steps in weaning
• Post-extubation care
• Factors in weaning difficulty
• Tracheostomy and Long term care

4. Need not be gradual in all cases
80% of individuals needing temporary mechanical ventilation can be disconnected
Liberation or discontinuation are now the preferred terms
Weaning trials must be started for any patient who has been mechanically ventilated for 24
hours or more
Definition
Pilbeam's mechanical ventilation: physiological and clinical applications. 2012
The process of gradual discontinuation of ventilatory support from a patient

5. Problems with Mechanical Ventilation
Sellares J. Intensive Care Medicine. 2011

6. Boles J-M. European Respiratory Journal. 2007
Stages of Weaning

7. Topic Outline
• Introduction
• Steps in weaning
• Post-extubation care
• Factors in weaning difficulty
• Tracheostomy and Long term care

8. Readiness Testing
Weaning Methods
Extubation
Steps in Weaning

9. Readiness testing

10. Epstein S K. AJRCCM. 2000
 Clinicians underestimate the ability of a
patient to be weaned
 50% of self-extubated patients do not
require re-intubation
 65 – 85% of patients are ready to be
weaned on the first day of assessment
 To prevent harms of premature weaning
 Cardiac failure, respiratory failure, re-
intubation
To Wean Or Not to Wean
That is the question

11. Clinical
Criteria Weaning
Predictors

12. Clinical Criteria
Objective clinical values depicting the physiology of the patient to test readiness for weaning
30% patients who never satisfy conditions can also be weaned
Subjective criteria
Cause of respiratory failure has improved
Objective criteria
Adequate oxygenation PaO2 ≥ 60mmHg on FiO2 ≤ 40%
PEEP ≤ 5 – 8 cmH2O
PaO2/FiO2 ≥ 150
Stable cardiovascular system HR ≤ 140 bpm
Stable blood pressure with minimal/no vasopressors
Afebrile Temperature ≤ 38˚C
Metabolic status No respiratory acidosis (pH ≥ 7.25)
Acceptable electrolytes
Adequate mentation Alert/Easily arousable
No sedative infusions
Adequate Hemoglobin Hb ≥ 8 g/dL
MacIntyre N R. Chest. 2001

13. Weaning Predictors
Physiologic tests to test readiness for weaning
Study oxygenation and gas exchange, respiratory muscle capacity, load on the
respiratory system
May require special equipment for testing
Best studied and most reliable – Rapid Shallow Breathing Index

14. Oxygenation and Gas
Exchange
• PaO2/FiO2
• PaO2/PAO2
• (A-a) gradient
Respiratory system load and
muscle capacity
• Maximal Inspiratory Pressure
(MIP) (< -20 cmH2O)
• Compliance (Static and
Dynamic)
• Minute Ventilation
(< 10L/min)
• Respiratory frequency
(< 35/min)
• Tidal Volume (> 4 – 6mL/kg)
Integrative Indices
• RSBI (< 105
breaths/min/L)
• CROP Index
• CORE Index
• Integrative Weaning
Index (IWI)
Respiratory Drive
• P0.1 (> -6cmH2O)
• P0.1/MIP
Meade M. Chest. 2001
Weaning Predictors

15. PaO2 ≥ 60mmHg (FiO2 ≤ 40%)
PEEP ≤ 5 – 8 cmH2O
PaO2/FiO2 ≥ 150
PaO2/PAO2 > 0.47
(A-a) < 350mmHg (FiO2 = 100%)
𝑃𝐴𝑂2 = 𝐹𝑖𝑂2 × (𝑃𝑎𝑡𝑚 − 𝑃𝐻2𝑂) −
𝑃𝑎𝐶𝑂2
0.8
Adequacy of Oxygenation
Pilbeam's mechanical ventilation: physiological and clinical applications. 2012

16. Respiratory system load and muscle capacity
Vital Capacity > 15mL/kg (IBW)
Minute Ventilation < 10 – 15L/min
Tidal Volume > 4 – 6mL/kg (IBW)
Respiratory rate < 35/min
Ventilatory pattern – Synchronous
and stable
MIP < -20 to -30 cmH2O
Pilbeam's mechanical ventilation: physiological and clinical applications. 2012

17. Others
Dynamic Compliance > 25mL/cmH2O
Static Compliance > 33mL/cmH2O
P0.1 > -6 cmH2O
Pilbeam's mechanical ventilation: physiological and clinical applications. 2012

18. RSBI
RSBI (breaths/min/L) = Respiratory rate (f) / Tidal Volume in L (Vt)
• Measured at least 1 minute after disconnecting from ventilator
• Threshold for successful weaning < 105 breaths/min/L

19. How though?

20. Tobin MJ. Intensive Care Medicine. 2006

21. Preparation for weaning
 Communicate with the patients
 Explain the procedure and calm them
 Record baseline parameters
 Keep a calm environment
 Position the patient upright in bed
 Suction the ET tube to ensure patency

22. Weaning methods

23. Spontaneous Breathing Trial (SBT)
Reduction in pressure support of PSV
Reduction in IMV support
Newer Methods

24. Spontaneous breathing trial
Weaning Technique Relative rate of success P value
Once daily SBT vs IMV 2.83 (1.36 – 5.89) < 0.006
Once daily SBT vs PSV 2.05 (1.04 – 4.04) < 0.04
Once daily SBT vs Intermittent SBT 1.24 (0.64 – 2.41) 0.54
130 of 546 patients failing a 2 hour SBT randomly assigned to wean via
daily SBT (using a T-piece), IMV or PSV
Esteban A. NEJM. 1995

25. 300 patients enrolled in a two arm RCT
Shorter duration of weaning (4.5 vs 6 days; p = 0.003)
Lower rates of post extubation respiratory failure (20%
vs 40%; p = 0.001)
Ely EW. NEJM. 1996

26. Types of SBT
T-Piece trial
Low levels of PSV (5 – 8 cmH2O)
Low level CPAP (5 cmH2O)
Automatic Tube Compensation (ATC)

28. 2017 ACCP/ATS Clinical Practice Guidelines
• Based on a meta-analysis of 4 randomized trials
• Higher extubation success (75.4% vs 68.9%; RR = 1.09, 95% CI
1.02 vs 1.18)
SBT be conducted with inspiratory pressure augmentation (5-8 cm
H2O) rather than without (T-piece or CPAP)
Ouellette DR. Chest. 2017

29. Automatic Tube Compensation?
Study/Year No of Patients Study Design Results Remarks
Haberthur C et al/2002 90 RCT
1. PSV
2. T- Piece
3. ATC + CPAP 5 cm H20
Rate of successful
extubation similar with
modes
Half the patients who
failed with PSV or T-
tube tolerated ATC -
successfully extubated
Cohen JD et al/2006 99 RCT
1. CPAP
2. CPAP + ATC
Extubation
96% vs 85%,
p = 0.08
Cohen JD et al/2009 180 RCT
1. ATC
2. PSV
Extubation
94% vs 86%
p = 0.12
Higher predictive value
of RSBI in ATC

30. Duration of SBT
Minimum of 30 minutes and can go up to 120 minutes
30 minutes and 120 minutes of T Piece trials have similar outcomes
(526 patients, 75.9% vs 73.0%, p = 0.43)
Patient’s failing an initial SBT or those requiring prolonged ventilation may
require 120 minute SBT
Esteban A. AJRCCM. 1997

31. Liang G. Respiratory Care. 2018

32. Subjective failure of SBT
Agitation and anxiety
Depressed mental status
Diaphoresis
Cyanosis
Increased accessory muscle activity
Facial signs of distress
Esteban A. NEJM. 1995; Ely EW. AJRCCM. 1999

33. Objective failure of SBT
Respiratory rate > 35 breaths/min (Or increase in 10 breaths/min or
decrease in 8 breaths/min below baseline)
Tidal volume < 250mL to 300mL
Heart rate > 140bpm or > 20% from baseline
Sudden onset VPC (more than 4 to 6 per minute)
Significant change in blood pressure
- Drop of 20 mmHg systolic
- Rise of 30 mmHg systolic
- SBP >180 mmHg
- Change of > 10 mmHg of diastolic
Desaturation with SO2 < 90% or PaO2 < 60mmHg (FiO2 ≤ 40%)
Esteban A. NEJM. 1995; Ely EW. AJRCCM. 1999

34. SBT
Success Extubation
Failure
Daily SBT
Early extubation to NIV

35. Failed SBT
Daily SBT vs Intermittent
SBT – showed no difference
in weaning success
Diaphragmatic fatigue
appears within the first 24
hours of mechanical
ventilation
Find the etiology for
failure
Laghi F. J Appl Physiol. 1995

36. Weaning with PSV
SBT/Extubate
PS 6 – 8
cmH2O and
PEEP = 5cm
H2O
Reduce PS by
2 – 4 cmH2O
twice daily
Monitor
clinically
Set PS about
80% of
Ppeak
Record Vt
and Ppeak
More useful in prolonged weaning
SBTs after reduction in PS by 50%
IMV is not used for weaning

37. Extubation

38. Extubation
Removal of the endotracheal tube
Final step in liberating patient from mechanical ventilation
Safety of extubation must be assessed prior to extubation

39. Assessment of airway protection
Cough Consciousness Secretions

40. Consciousness:
- Ideal - alert/arousable
- Neck Holding: Hold neck off the bed for 5 seconds
Secretions:
- Thick secretions not a contraindication
- Suctioning < 2 – 3 hours
Cough:
- Assessed during deep suctioning
- PEF ≥ 60 L/min (Spirometry)
- Index card – Ability to wet a card 1 – 2 cm from ETT
Salam A. Intensive Care Medicine. 2004

41. Post-extubation stridor
Incidence: <10% of cases
Causes: Vocal cord edema, laryngeal injury, vocal cord dysfunction
Risk factors:
Jaber S. Intensive Care Medicine. 2003
Prolonged intubation
Age > 80 years
Female gender
Ratio of ETT to laryngeal diameter > 45% (On CT)
ETT size > 8mm in men and > 7mm in women
Traumatic intubation
History of asthma
Excessive tube motility due to improper fixation

42. Cuff Leak Test
Qualitative: Listening to air movement around the ETT
Quantitative:
 In Volume controlled ventilation
 < 110mL or less than 12 – 24% of Vti – Negative cuff leak
 Sensitivity: 15 – 85%; Specificity: 70 – 99%
Vti – Vte
> 110mL
Associated with adequate
patency of airway
(Specificity 99%)
Kriner EJ. Respiratory Care. 2005

43. Role of glucocorticoids
Khemani RG. Cochrane Library. 2009

44. Selecting the right patient is more important
than the number of doses administered
Acceptable regimens:
Role of glucocorticoids
Khemani RG. Cochrane Library. 2009
IV Methylprednisolone 20mg Q4H for 4 doses
IV Methylprednisolone 40mg Single dose 4 hours prior

45. Topic Outline
• Introduction
• Steps in weaning
• Post-extubation care
• Factors in weaning difficulty
• Tracheostomy and Long term care

46. Weaning success: 48 hours of unassisted breathing
Hoarseness, sore throat and cough are common
Post-extubation stridor:
 Treat with nebulized racemic epinephrine (0.5mL, 2.25% epinephrine in 3mL NS)
 Heliox treatment (70% Helium and 30% Oxygen)
 Steroids
 May require re-intubation
Post-extubation care
Pilbeam's mechanical ventilation: physiological and clinical applications. 2012

47. Post-extubation respiratory failure
Risk factors
• Age > 65 yr
• > 1 SBT failure
• Chronic heart failure
• PaCO2 > 45 mmHg after extubation
• Medical/surgical co-morbid illness
• Poor cough reflex
• BMI > 35 kg/m2
Fernando Frutos-Vivar,et al Chest 2006

48. All extubated patients must be oxygenated
For patients at high risk for extubation failure who have been receiving mechanical
ventilation for more than 24 hours, and who have passed a spontaneous breathing
trial, we recommend extubation to preventative NIV (Strong recommendation,
moderate grade of evidence).
ACCP/ATS Guidelines
High Risk Low Risk
NIV is recommended Low flow oxygen
High flow oxygen
Ouellette DR. Chest. 2017

49. Topic Outline
• Introduction
• Steps in weaning
• Post-extubation care
• Factors in weaning difficulty
• Tracheostomy and Long term care

50. Weaning
Failure
Failure of SBT
Re-intubation
within 48
hours

51. Types of weaning
Simple Weaning (70%)
• Single SBT
Difficult Weaning (10 – 20%)
• 1 to 3 SBT
• Weaned within 7 days
Prolonged Weaning (10 – 15%)
• More than 3 SBT
• Weaning takes more than 7 days from first SBT
Boles JM. Eur Respir J. 2007

52. PO4
Mg K
Ca
Weaning Failure

53. Respiratory factors
RESPIRATORY LOAD
Inappropriate ventilator settings – Increased WoB
Reduced compliance
• Pneumonia
• Pulmonary edema
• Pleural effusion
Increased resistive load
• Narrow ET tube
• Bronchoconstriction
• Increased airway secretions
• Post-extubation: glottic oedema
RESPIRATORY DRIVE
• Sedation
• Metabolic alkalosis
• CVA, encephalitis,
cerebral edema
RESPIRATORY MUSCLE STRENGTH
• Nutrition
• Ventilator induced diaphragmatic dysfunction
• Metabolic disturbances
K/Ca/Mg/PO4
• Critical illness neuromyopathy
Eskandar. Crit Care Clin. 2007

54. Cardiac Factors
Weaning induced ischemia/failure: 20 – 60% cases of difficult weaning
Difficult to identify if SBT is performed with PEEP
Pro-BNP levels: Difficulty is expected if
- Elevated levels before SBT
- Elevated levels after an SBT
- > 20% rise during an SBT
2D Echo: Helps identify systolic or diastolic dysfunction

55. Neuromuscular causes
Central causes: OSA with hypoventilation, central apneas, stroke
Critical illness myopathy/polyneuropathy
- ≥ 25% of mechanically ventilated patients after 7 days
- Risk Factors: Sepsis, Multi-organ failure, SIRS
- Abrupt onset over 24 hours or progress over days
- Aggressively treat the underlying cause

56. Metabolic causes PO4
Mg K
Ca
Raised pCO2 in
chronic
hypercapnia
Bicarbonate
excretion
during MV
Acute
respiratory
acidosis
during SBT
Falsely
interpreted
as failure of
SBT
Metabolic acidosis causes compensatory Respiratory alkalosis – Increase in the work
of breathing
Hypothyroidism

57. Drugs and sedatives
Aminoglycosides – Neuromuscular
blockade – Rare cause of weaning failure
ATS Recommendation
For acutely hospitalized patients ventilated
for more than 24 h, we suggest protocols
attempting to minimize sedation
Strom T. Lancet. 2010

58. Nutrition
Ventilated patients with severe infection can be given up to
35kcal/kg
Undernutrition
- Wasting of muscles (including diaphragm and cardiac)
- Blunts central response to hypoxia and hypercapnia
Overnutrition
- Increased metabolic rate and increased workload on the
respiratory system due to CO2 production

59. Psychological
Depression, anxiety, delirium, pain
Depression - 40% patients undergoing prolonged weaning
Patients with delirium can be twice as hard to wean
How to tackle?
- Explain the process to the family and caregivers
- Medications to treat psychiatric issues and adjustment of sedative doses
- Reassurance
- Adequate sleep and a stimulating environment

60. • 60 year old male
• COPD and CAD
• Admitted for CAP
• Intubated in view of respiratory failure
• Condition improved with antibiotics
• Decided to be weaned
• SBTs initiated – failed – Tachycardia; Tachypnea
Ramu Re-admitted (A case scenario)

61. Vt Ppeak
RR Pplat
MVe PEEP
400 28
2522
8.8 6
SBT
Vt Ppeak
RR Pplat
MVe PEEP
200 40
2944
8.8 6

62. Vt Ppeak
RR Pplat
MVe PEEP
400 28
2522
8.8 6
SBT
Vt Ppeak
RR Pplat
MVe PEEP
200 40
3844
8.8 6

63. Vt Ppeak
RR Pplat
MVe PEEP
400 28
2522
8.8 6
SBT
Vt Ppeak
RR Pplat
MVe PEEP
500 30
2630
15 6

64. Topic Outline
• Introduction
• Steps in weaning
• Post-extubation care
• Factors in weaning difficulty
• Tracheostomy and Long term care

65. Advantages:
◦ Easier airway management
◦ Improved patient comfort and communication
◦ Reduction in sedative use
◦ Earlier transition to oral feeding
◦ Reduced oropharyngeal trauma
◦ Prevention of VAP
Disadvantages
◦ Long term risk of tracheal stenosis
◦ Procedure-related complication rate (4% - 36%)
Tracheostomy
Griffiths J. BMJ. 2005

66. Meta-analysis of the data from studies
Significant effect on the duration of mechanical ventilation and the length of stay in intensive
care
Unable to confirm an effect of early (2- 10 days) tracheostomy in reducing the risk of pneumonia
or death
Strong consideration for those likely to need mechanical ventilation for more than 2 weeks
Tracheostomy - timing
Griffiths J. BMJ. 2005

67. Site where weaning and rehabilitation are the primary focus
 Acute condition of the patient has to be resolved
 Patient should be stable on a mechanical ventilator
 Stable airway and a route for nutrition
Consists of intensivists, internists, nurses and respiratory therapists who identify
weaning goals and coordinate the weaning process
Long term care facilities

68. Newer modes for weaning

69. NAVA – Neurally Adjusted Ventilator Assist
Verbrugghe W. Respiratory Care. 2011

70. NAVA - Synchrony
Problems of asynchrony
• Increased need of sedation and
muscle relaxants
• Increased transpulmonary
pressure – Barotrauma
• Prolonged duration of ventilation
Verbrugghe W. Respiratory Care. 2011

71. Respiratory
Rate
No trigger
PCV
Spont <
Target
PS/SIMV
Spont >
Target
PSV
Adaptive Support Ventilation
Advantages
Provides Automated weaning
Fewer human resources are needed at bedside
Fernandez J. Indian J Crit Care Med. 2013

72. Take Home Message
 Test readiness before weaning
 Daily SBT with inspiratory augmentation
 Mechanical ventilation for > 2 weeks : Early tracheostomy
 If weaning fails, look thoroughly for the cause and correct
 NAVA and ASV are newer, more advanced modes for weaning

73. Thank you