This document provides an overview of evidence and guidelines for weaning patients from mechanical ventilation, with a focus on neurological patients. It discusses definitions of weaning, the interaction between the brain and lungs, weaning algorithms, classifications of weaning difficulty, factors influencing weaning success, and assessments used to determine patient readiness for weaning trials. The execution of weaning involves conducting spontaneous breathing trials to assess tolerance of breathing without support before considering extubation. Research studies are referenced that evaluated outcomes of protocolized versus non-protocolized weaning approaches in ICU patients.

1. WEANING FROM MECHANICAL
VENTILATION IN NEUROLOGICAL PATIENTS-
AN EVIDENCE BASED APPROACH
SUCHARITA RAY
PRECEPTOR:
DR KARAN MADAN
DR DEEPA DASH
01/01/2015

2. THE CHECKLIST
 DEFINITION OF WEANING
 THE BRAIN LUNG INTERACTION
 WEANING ALGORITHM
 CLASSIFICATION AND PATHOPHYSIOLOGY
 THE EXECUTION
 CRITICAL ILLNESS NEUROMUSCULAR
ABNORMALITIES
 NEWER MODALITIES OF WEANING

3. DEFINITION OF WEANING
Hall JB et al, JAMA; 1987
Slutsky AS, Chest 1993
“Gradual withdrawal
of mechanical ventilation and concomitant resumption
of
spontaneous breathing”
•Ventilatory assistance NEED NOT BE DECREASED
GRADUALLY in all patients with acute respiratory failure
•“LIBERATION FROM" and “DISCONTINUATION OF“
mechanical ventilation are now preferred

4. SOME PRELIMINARIES
• 30% of patients admitted to ICUs require
mechanical ventilation
• Delayed weaning increases costs, risks of
nosocomial pneumonia, cardiac-associated
morbidity, and death.
• Early weaning often results in reintubation, and
associated complications due to prolonged
ventilation
Esteban A, Anzueto A, Frutos F, et al. Characteristics and outcomes in adult patients
receiving mechanical ventilation: a 28-day international study. JAMA 2002; 287:345–355.

5. JAMA 2002, Vol 287, No 3 ( Reprint)

6. Context of the Research:
To study the outcome of mechanical ventilation in a large
number of unselected, heterogeneous patients.
Objectives
1. To determine the survival of patients receiving
mechanical ventilation
2. Relative importance of factors influencing
survival.
Esteban A et al. Characteristics and Outcomes in Adult Patients Receiving
Mechanical Ventilation: A 28-Day International study. JAMA.2002;287(3):345-355.

7. Design, Setting, and Subjects:
• Prospective cohort of consecutive adult patients
• Admitted to 361 ICUs
• Received mechanical ventilation for more than 12 hours
• March 1, 1998 - March 31, 1998.
Main Outcome Measure:
All-cause mortality during ICU unit stay.
Esteban A et al. Characteristics and Outcomes in Adult Patients Receiving
Mechanical Ventilation: A 28-Day International study. JAMA.2002;287(3):345-355.

8. SOME OF THE NUMBERS INVOLVED:
• Total number of patients admitted in the study period: 15757
 MEDICAL/SURGICAL: 77%
 MEDICAL 19%
 SURGICAL 4%
• Total number of patients receiving mechanical ventilation for
more than 12 hours: 5183 (33%)
• Total number of patients followed up for entire course of
mechanical ventilation: 5131 ( 99%)

10. THE ATTEMPT AT WEANING:
TOTAL NUMBER: 5199 attempts in 3640 (70.2%) patients
• Once-daily weaning trial--- 2833 (77.8%) attempts
• Multiple weaning trials--- 510 (14.0%) attempts
• Gradual reduction of pressure support--- 752 (20.7%)
attempts
WEANING METHODS:
• T-tube------------------1725 (51.6%) attempts
• CPAP------------------ 643 (19.2%) attempts
• PS of 7 cm H2O---- 943 (28.2%) attempts

12. FACTORS INDEPENDENTLY ASSOCIATED
WITH MORTALITY
Age
SAP II Score at ICU Admission
Prior functional status
MV initiated due to coma of any cause
ARDS
Sepsis
Inotropic support
MODS
JAMA, January 16,2002; Vol 287, No 3

13. Lone and Walsh Critical Care 2011, 15:R102

14. METHODS: Retrospective Cohort Study
STUDY LOCATION: 3 ICU units in a UK region from 2002 to
2006.
PROLONGED MECHANICAL VENTILATION: Requiring
mechanical ventilation 21 days or more
OUTCOMES: Mortality and Hospital Resource Use
Lone and Walsh Critical Care 2011, 15:R102

16. Age mean (SD) 349 7,499 59.6 (15.2) 56.9 (18.1) 0.001
CPR in 24 hours before
ICU admission n (%)
349 7,499 23 (6.6) 663 (8.8) 0.15
Number of co-morbidities
n (%)
340 7,228 <0.001
None 276 (81.2) 5,317(73.6)
1 50 (14.7) 1,211 (16.8)
2 or more 14 (4.1) 700 (9.7)
Surgical status n (%) 347 7,463 <0.001
Tracheostomy placed
during admission n (%)
349 7,499 219 (62.8) 470 (6.3) <0.001

17. ICU mortality n (%) 317 7,103 83 (26.2) 1,654
(23.3)
0.23
Hospital mortality n (%) 305 6,763 123(40.3) 2,286(33.8) 0.02
Length of ICU stay (days)
Mean no of days
349 7,499
37.2(16.1) 3.8 (4.9)
No of days ventilated
Mean (SD)
349 7,499
33.2 14.7) 2.9 (4.2)

18. THE BRAIN LUNG INTERACTION
ARDS survivors show persistent cognitive deterioration at
discharge
Mechanisms of cognitive dysfunction?
Hypoxemia
Hypoxia- HIF-1alpha and HIF-2alpha
HYPOXIA INDUCED FACTORS HAVE A ROLE IN:
Angiogenesis,
Energy metabolism
Cell survival/ Neural stem cell growth
Miltbrand EB, Angus DC: Potential mechanisms and markers of critical illness-associated cognitive
dysfunction. Curr Opin Crit Care 2005, 11:355-359.

19. There is no such thing as an isolated head injury
Target of MODS.
Progression to ALI
Delirium
Dementia
Cognitive decline
Loss of IQ
Mood disorders
Memory disorders
MAN MACHINE MAN
Gonzalvo R, Marti-Sistac O, Blanch L, Lopez- Aguilar J. Bench-to-bedside review: brain-lung interaction
in the critically ill–a pending issue revisited. Crit Care. 2007;11(3):216.

20. (1) improve brain oxygenation
THERAPEUTIC TARGETS OF VENTILATION IN THE
NEUROLOGICALLY ILL PATIENT
(2) improve cerebral blood flow.
(3) discordant therapeutic targets
Lowe GJ, Ferguson ND. Lung-protective ventilation in neurosurgical patients. Curr Opin Crit Care. 2006;12(1):3

21. YES / NO? IF YES THEN HOW
THE NEURO ICU GUY ON A VENTILATOR

22. Cochrane Database of Systematic Reviews 2014, Issue 11. Art. No.: CD006904.
DOI: 10.1002/14651858.CD006904.pub3.

23. OBJECTIVES
1. Comparison of total duration of mechanical ventilation of
using protocols versus non-protocolized practice.
2. Differences in outcomes measuring weaning duration, harm
(adverse events) and resource use (intensive care unit
(ICU) and hospital length of stay, cost)
3. Variations in outcomes by type of ICU, type of protocol and
approach to delivering the protocol (professional-led or
computer-driven).
Cochrane Database of Systematic Reviews 2014, Issue 11. Art. No.: CD006904.
DOI: 10.1002/14651858.CD006904.pub3.

24. SELECTION CRITERIA:
Randomized controlled trials (RCTs) and quasi-RCTs of
protocolized weaning versus non-protocolized weaning in
critically ill adults.
Main results:
17 trials (with 2434 patients)
Cochrane Database of Systematic Reviews 2014, Issue 11. Art. No.: CD006904.
DOI: 10.1002/14651858.CD006904.pub3.

25. AUTHORS’ CONCLUSIONS
Use of protocols can be said to have:
1. Reduced duration of mechanical ventilation
2. Reduced weaning duration
3. Reduced length of ICU stay
Protocolized approach brought about these reductions in
medical, surgical and mixed ICUs
Protocolized approach did not bring about any effect in
neurosurgical ICUs.
Cochrane Database of Systematic Reviews 2014, Issue 11. Art. No.: CD006904.
DOI: 10.1002/14651858.CD006904.pub3.

26. JM Boles et al Eur Respir J 2007: 29: 1033-1056
A Esteban et al Chest 1994: 106: 1188-1193
Tindol GA et al Chest 1994: 105: 1804-1807
Admit Discharge
Treatment of
ARF
Assess
readiness
to wean
Extubation ? Reintubation
Suspicion SBTSuspicion
Assess
readiness
to wean
40- 50% of total duration of
mechanical ventilation
Unplanned extubation – 0.3- 16%
~50% do not require re intubation
THE WEANING ALGORITHM

27. TERMINOLOGY
Extubation & absence of
ventilatory support 48hrs post
extubation
Failed SBT
Reintubation/resumption of
ventilatory support post extubation
Death within 48hrs post extubation
S
U
C
C
E
S
S
F
A
I
L
U
R
E
JM Boles et al Eur Respir J 2007: 29: 1033-10

28. CLASSIFICATION
SIMPLE
• 70 %
• Single SBT
DIFFICULT
• 15 – 20 %
• Upto 3 SBT
• Upto 7 days
after first SBT
PROLONGED
• 10 - 15%
• > 3 SBT
• > 7 days after
first SBT
JM Boles et al Eur Respir J 2007: 29: 1033-10

29. PATHOPHYSIOLOGY
• Neuromuscular - CINMA
• Neuropsychological
• VIDD
• Metabolic
• Overweight
• Baseline Status
• Demand
• Airway
Resistance
• Compliance
• Settings
Respiratory Cardiac
Neurological
Nutritional
and
Metabolic
VIDD : Ventilator Induced Diaph. Dysfunction CINMA : Critical Illness NeuroMusc
Abnromalities

30. RESPIRATORY LOAD
Increased
WOB
Inappropriate
ventilator settings
Patient ventilator
dyssynchrony
Compliance
Pneumonia
Pulmonary edema
Fibrosis
Chest wall
Resistance
Bronchospasm
DHI
ET tube
Glottic edema
JM Boles et al Eur Respir J 2007: 29: 1033-10

31. JM Boles et al Eur Respir J 2007: 29: 1033-10
A Esteban et al Chest 1994: 106: 1188-1193
Tindol GA et al Chest 1994: 105: 1804-1807
Admit
?
Discharge
Treatment of
ARF
Assess
readiness
to wean
SuspicionSuspicion
Assess
readiness
to wean

32. Identifying Candidates for a Trial of
Spontaneous Breathing
MacIntyre NR. Evidence-based assessments in the ventilator discontinuation process. Respir Care 2012;
57:1611–1618.
Respiratory Criteria:
PaO2 ≥ 60 mm Hg on FiO2 ≤ 0.4;
PEEP ≤ 5–10 cm H2O;
PaO2/FiO2 ≥ 150–300)
PaCO2 at normal or baseline levels
Able to initiate a respiratory effort ( PI max > - 30 cm H20)
Cardiovascular Criteria
Stable CV System
( HR ≤ 140; stable BP; no (or minimal) pressors)

33. Identifying Candidates for a Trial of
Spontaneous Breathing
MacIntyre NR. Evidence-based assessments in the ventilator discont process. Respir Care 2012;
57:1611–1618.
Appropriate Mental Status
Adequate mentation
(Arousable, GCS ≥ 13, no continuous sedative infusions)
Absence of Correctible Comorbid Conditions
Afebrile (temperature 38°C)
Adequate hemoglobin (Hb 8–10 g/dL)
Stable metabolic status (Acceptable electrolytes)
Physician believes in possibility of discontinuation

34. READINESS ASSESSMENT
“The Wean Screen”
Subjective
Adequate cough
Absence of excessive
tracheobronchial
secretion
Resolution of disease
acute phase
Objective
Hemodynamic stability
Stable metabolic status
Adequate oxygenation
Adequate mentation
Adequate pulmonary
function
JM Boles et al Eur Respir J 2007: 29: 1033-1056

35. Measurements Used to Predict a Successful Trial of
Spontaneous Breathing
Measurement Threshold for
Success
Range of
likelihood Ratios
Tidal Volume (Vt) 4-6 ml/kg 0.7-3.8
Respiratory Rate
(RR)
30-38 bpm 1.0-3.8
RR/Vt Ratio 60-105 bpm/L 0.8-4.7
Maximum
Inspiratory Pressure
( P I max)
-15 to -30 cm of
H2O
1.0-3.0
MacIntyre NR. Evidence-based assessments in the ventilator discontinuation process. Respir Care 2012;
57:1611–1618.

36. JM Boles et al Eur Respir J 2007: 29: 1033-1056
A Esteban et al Chest 1994: 106: 1188-1193
Tindol GA et al Chest 1994: 105: 1804-1807
Admit ? Discharge
Treatment of
ARF
Assess
readiness
to wean
Suspicion SBT

37. THE SPONTANEOUS BREATHING TRIAL
THE TRADITIONAL APPROACH:
 Gradual reduction in ventilatory support over hours to days
 Put patients back on a ventilator at night to “rest them”
 Spontaneous breathing trials (SBTs) are conducted with no
ventilatory support
(To help identify patients capable of unassisted breathing)

38. Using the
Ventilator Circuit
Pressure
Support
Disconnecting
the Ventilator
METHODS OF SPONTANEOUS BREATHING
TRIALS

39. FORMS OF SPONTANEOUS BREATHING
TRIALS
Low level of
CPAP (5 cm
H2O)
Low levels of
PSV (5-8 cm
H2O)
Flow-triggering
with no
pressure
support
T- piece
breathing
Esteban A et al Am J Respir Crit Care Med 1

40. I-Using the Ventilator Circuit
 Often conducted while the patient breathes through the
ventilator circuit.
 Advantage: Can monitor the tidal volume (VT) and
respiratory rate (RR),
 Rapid, shallow breathing (indicated by an increase in
the RR/VT ratio) is a common breathing pattern in
patients who fail the SBT.
 Drawback: Resistance to breathing through the
ventilator circuit  Increased work of breathing

41. II-Pressure Support
 Low levels of pressure support (5 cm H2O) are used.
 To counteract the resistance to breathing through the
ventilator circuit,
 What is the benefit?

42. No PSV PSV 1 Hr Post Extubn
Number of Patients 50 40 90
50
40
90
WorkofbreathingJ/L
Number of Patients
Work of Breathing during SBT with/out PSV
Mehta S, Nelson DL, Klinger JR, et al. Prediction of post-extubation work of
breathing. Crit Care Med 2000; 28:1341–1346.

43. Simple breathing circuit for spontaneous breathing trials
that are independent of the ventilator.
The T-shaped adapter in the circuit is responsible for the
popular term T-piece that is used for this circuit
The T-piece

44. The theoretical advantages of the T-piece
The work of breathing is lower when breathing
through a T-piece circuit compared to a
ventilator circuit (although this is unproven).
The major disadvantage of the T-piece circuit is the
inability to monitor the respiratory rate and tidal
volume.

45. RSBI – Rapid Shallow Breathing Index
• 1 min after spontaneous breathing
• < 105 breaths/min/l
Yang KL, TobinMJ, N Engl J Med 1991
RSBI = Respiratory rate (per min)
Tidal volume (L)

46. SEARCH PERIOD: 1971 to 1998
DATABASES SEARCHED: MEDLINE, EMBASE,
HealthSTAR, CINAHL, the Cochrane Controlled Trials
Register and the Cochrane Database of Systematic
Reviews.

47. Weaning interventions:
‘For stepwise reductions in mechanical support,
PSV/multiple daily T-piece trials could be superior to
SIMV.’
‘For trials of unassisted breathing, low levels of pressure
support could be beneficial.’
These thresholds are not completely based on
objective data and appear to be related to
physician judgement.

48. JM Boles et al Eur Respir J 2007: 29: 1033-10
A Esteban et al Chest 1994: 106: 1188-1193
Tindol GA et al Chest 1994: 105: 1804-1807
Admit Discharge
Treatment of
ARF
Assess
readiness
to wean
Extubation ? Reintubation
Suspicion SBT

49. (CHEST 2006; 130:1664–1671)
“ To assess the factors associated with reintubation
in patients who had successfully passed a SBT.”

50. Methods:
Prospectively collected clinical data from adults admitted to
ICUs of 37 hospitals in eight countries
Readiness-to-wean criteria:
(1) Improvement in the underlying condition that led to ARF
(2) Alert/able to communicate
(3) Core temperature not > 38°C
(4) No therapy with vasoactive drugs
(5) Adequate gas exchange, as indicated by a Po2 of at least
60
Undergone invasive mechanical ventilation for > 48 h
Deemed ready for extubation.

52. Success vs. Failure
1. Signs of respiratory distress: Agitation, diaphoresis,
rapid breathing, and use of accessory muscles of respiration.
2. Signs of respiratory muscle weakness:
Paradoxical inward movement of the abdominal wall during
inspiration.
3. Adequacy of gas exchange in the lungs: PaO2,
PaO2/FIO2 ratio, arterial PCO2, and gradient between end-tidal
and arterial PCO2.
4. Adequacy of systemic oxygenation: Central
venous O2 saturation.

53. SBT FAILURE - SUBJECTIVE
Agitation and anxiety
Depressed mental status
Diaphoresis
Cyanosis
Increased accessory muscle activity
Facial signs of distress
Thoraco-abdominal paradox
Esteban A et alN Engl J Med 1995 Ely EW et al, Am J Respir Crit Care Med
1999

54. SBT FAILURE - OBJECTIVE
PaO2 < 50–60 mmHg or SaO2 < 90% on FIO2 > 0.5
PaCO2 >50 mmHg or an increase in PaCO2 >8 mmHg
pH < 7.32 or a decrease in pH > 0.07 pH units
fR/VT > 105 breaths/min/L
fR > 35 breaths/min or increased by >50%
A
B
G
VENTILATOR
Esteban A et alN Engl J Med 1995: Ely EW et al, Am J Respir Crit Care Med 1999
CARDIOVASCULAR
fC >140 beats/min or increased by >20%
Cardiac arrhythmias
Systolic BP > 180 mm Hg or increased by
>20%
Systolic BP <90 mm Hg

55. • A majority of patients (∼80%) who tolerate
SBTs for 2 hours can be permanently
extubated
• Longer periods of SBTS for patients with
prolonged periods of ventilator dependence
(≥3 weeks)
• For patients who fail initial attempts at
unassisted breathing  daily SBTs.
MacIntyre NR, Cook DJ, Ely EW Jr, et al. Evidence-based guidelines for weaning and
discontinuing ventilatory support: a collective task force facilitated by the ACCP, the AARC, and
the ACCCM. Chest 2001; 120(Suppl):375S–395S.

56. NEUROMUSCULAR COMPETENCE
CINMA : Critical Illness NeuroMuscular
Abnormalities
CoplinWM, Am J Respir Crit Care Med 2000
Depressed central
drive
Encephalitis/ ischemia
Metabolic alkalosis
Sedatives and hypnotics
Peripheral dysfunction
GBS, MG, MND
CINMA
VIDD
Drug induced

57. Critical Illness Neuromuscular
Abnormalities (CINMA)
• Most frequent acute polyneuropathy in ICUs
• Incidence 30- 58% (80% in MODS, 100% in septic
shock)
• Bilateral symmetrical proximal motor deficit
• Sensorimotor axonopathy
• Limb and respiratory muscle weakness
• Strongly associated with failed weaning
• Lasts months to years after discharge
Severity of illness
Duration of multiple (≥ 2) organ dysfunction
Duration of vasopressor and catecholamine support
Duration of ICU stay
Hyperglycaemia
Female sex
Renal failure and renal replacement therapy
Hyperosmolality
Parenteral nutrition
Low serum albumin
Neurological failure
Aminoglycosides
NMB and steroids
Nicola L. Lancet Neurol 2011; 10: 931–4

58. CINMA BUNDLE
Nicola L. Lancet Neurol 2011; 10: 931–4
A
B
C
D
E
Awakening
Breathing
Coordination of
awakening/
breathing
Delirium
assessment
Early exercise

59. CRITICAL ILLNESS NEUROMUSCULAR
ABNORMALITIES
First described in Canada and France in 1984.
The reported prevalence of CINMA : 50–100%
Most common peripheral neuromuscular disorders
encountered in the ICU setting & usually involve both muscle
and nerve.
CINMA is a function of :
Severity of illness,
Multiple organ dysfunction,
Exposure to corticosteroids,
Hyperglycemia
Prolonged ICU stay

60. Ventilator Induced Diaphragmatic Damage
(VIDD)
 Loss of diaphragmatic force-
generating capacity related to the
use of mech. ventilation
 Rapid onset (<18 hrs in animal
studies)
 Other causes to be ruled out
 Mechanism
 Muscle atrophy
 Muscle fibre remodelling
 Oxidative stress
 Structural injury
Jubran A; Respir Care; 2006
Vassilakopoulos T, Petrof BJ; Am J Respir Crit Care Med, 2004
MV 3 d
MV 47 d
• Avoid CMV if possible
• Patient Ventilator Synchrony
• Adequate nutrition
• Avoid steroids if possible – catabolic
effect
“ NAVA : Neurally Adjust
Ventilatory Assist”

61. ORIGINAL ARTICLE
Neuromuscular dysfunction associated with delayed
weaning from mechanical ventilation in patients with
respiratory failure
Yehia Khalil a, Emad El Din Mustafa a, Ahmed Youssef a,
Mohamed Hassan Imam b,*, Amni Fathy El Behiry

62. THE AIM OF THE STUDY:
To evaluate the role of the neuromuscular factors responsible for
difficult weaning from mechanical ventilation.
Methods: Total of 59 patients with 31 patients having PMV
*Prolonged mechanical ventilation duration ≥ 14 days
Successful weaning: 18 (58%)
Failed weaning ( & subsequent death): 13 (42%)
Study period: May 2009 - May 2010.
American Journal of Medicine (2012) 48, 223–232

63. American Journal of Medicine (2012) 48, 223–232
Corticosteroids intake and neuromuscular
dysfunction.
EMG / NCV findings with the outcome and
duration of mechanical ventilation

64. PI max and neuromuscular dysfunctions.
Albumin, Mg, Ca, Ph & neuromuscular dysfunctions.

65. NUTRITIONAL AND METABOLIC
FACTORS
Steroids
Myopathy
Glycemic control
Infections
Nutrition
Overweight
Malnutrition
Anemia
Trace elements
JM Boles et al Eur Respir J 2007: 29: 1033-1056

66. ROLE OF ELECTROLYTES
K Mg Ca PO4
+ 2+2+ 3-
* Benotti PN, Bistrian B. Metabolic and nutritional aspects of weaning from
mechanical ventilation. Crit Care Med 1989; 17:181–185.
** Malloy DW, Dhingra S, Solren F, et al. Hypomagnesemia and respiratory
muscle power. Am Rev Respir Dis 1984; 129:427–431

67. • DAILY T
PIECE
TRIALS
• PSV
SLOW
WEANING • SUCCESSFUL
WEANING
EXTUBATE AND
POST
EXTUBATION
CARE
• ROLE OF NIV
RE
INTUBATION
WHEN
REQUIRED
• DAILY SBT
• PRESSURE SUPPORT
WEANING
PSV : Pressure Support Ventilation NIV : Non Invasive Ventilation
SBT : Spontaneous Breathing Trial
WEANING PROCESS

68. NEGATIVE TO POSITIVE TRIAD
EXCESSIVE
SEDATION
EXCESSIVE
ASSIST
PATIENT-
VENTILATOR
ASYNCHRON
Y
PROLONGED
MECHANICAL
VENTILATION
PATIENT-
VENTILATOR
SYNCHRONY
SPONTANEOU
S
BREATHING
SEDATION
MANAGEMEN
T
EARLY
WEANING – 3
S

69. EXTUBATION
Removal of the artificial airway once the mechanical
ventilation is not deemed to be necessary

70. The basics of extubation*
• It should never be performed to reduce the
work of breathing
• The work of breathing can actually
increase after extubation
* Khamiees M, Raju P, DeGirolamo A, et al. Predictors of extubation outcome in patients who have successfully
completed a spontaneous breathing trial. Chest 2001; 120:1262–1270.

71. The basics of extubation*
The increased work of breathing is due to an increased
respiratory rate or breathing through a narrowed glottis
The considerations that must be addressed prior to extubation:
(a) the patient’s ability to clear secretions from the airways
(b) the risk of symptomatic laryngeal edema following
extubation.
* Khamiees M, Raju P, DeGirolamo A, et al. Predictors of extubation outcome in patients who
have successfully completed a SBT. Chest 2001; 120:1262–1270.

72. Criteria to define patients at high risk for
extubation failure
Nava et al. * Ferrer et al. **
Chronic heart failure Age >65 years
More than one consecutive
failed weaning trial
Cardiac failure
More than one comorbidity Apache II score >12 at
time of extubation
PaCO2 >45mmHg after
extubation
Weak cough
* Nava SG, Gregoretti C, Fanfulla F, et al. Noninvasive ventilation to prevent respiratory failure after extubation in high-risk
patients. Crit Care Med 2005; 33:2465–2470.
** Ferrer M, Valencia M, Nicolas JM, et al. Early non-invasive ventilation averts extubation failure in patients at risk. a
randomized trial. Am J Respir Crit Care Med 2006; 173:164–170.

73. ASSESSMENT BEFORE EXTUBATION
• Alertness and muscle function - Ability to lift the
head off of the bed for 5 seconds
• Adequate cough reflex (must not require
suctioning more than every 2 hours)
• Adequate airway patency - CUFF LEAK TEST
MacIntyre NR. Evidence-based guidelines for weaning and discontinuing ventilatory support: a collective task force.
Chest 2001; 120(Suppl): 375S–395S

74. Airway Protective Reflexes
 Protection determined by the strength of the gag and cough
reflexes.
 Cough strength: “ Hold a piece of paper 1–2 cm from the
end of the endotracheal tube and asking the patient to
cough. If wetness appears on the paper, the cough strength
is considered adequate.”
 *Diminished strength/absence of cough/gag reflexes will not
necessarily prevent extubation, but identifies patients who
need prevention from aspiration.
Bach JR, Saporito LR. Criteria for extubation and tracheostomy tube removal for patients with ventilatory failure: a
different approach to weaning. Chest 1996; 110:1566 –1571

75. Post Extubation Laryngeal Edema
(PELE)
• Upper airway obstruction from laryngeal edema is the
major cause of failed extubation
• Reported in 5–22% of patients who have been
intubated for longer than 36 hours.
• Contributing factors include difficult & prolonged
intubation, endotracheal tube diameter, and self-
extubation.
*Jaber S, Chanques G, Matecki S, et al. Post-extubation stridor in intensive care
unit patients. Risk factors evaluation and importance of the cuff test. Intensive
Care Med 2003; 29:63–74.

76. The Cuff-Leak Test
 The volume of inhaled gas that escapes through the larynx
when the cuff on the ET tube is deflated.
 Designed to determine the risk of symptomatic upper airway
obstruction from laryngeal edema after the endotracheal tube
is removed.
 Absence of air leak: High risk of upper airway obstruction
following
 Extubation

77. INTERPRETATION
• An air leak does not indicate a low risk of
upper airway obstruction following
extubation, regardless of the volume of
leak.
• Leak of less than 110 mL or 10 – 15% ?
• The test is not universally accepted. Results
of a cuff leak test do not alter patient
management
• Clinical relevance of the test is unproven.

78. REINTUBATION PARAMETERS
• RR > 25 breaths/min for 2 hrs
• HR > 140 beats/min or sustained increase or decrease
of >20%
• Clinical signs of respiratory muscle fatigue or increased
work of breathing
• SaO2 < 90%; PaO2 <60 mmHg on FIO2 >0.50
• Hypercapnia (PaCO2 >45 mmHg or >20% from pre-
extubation), pH <7.32
Fernando Frutos-Vivar,et al Chest 20

79. Pretreatment with Steroids?
 Pretreatment with intravenous corticosteroids :
 IV methylprednisolone, 20–40 mg every 4–6 hrs
 Duration: 12 to 24 hours prior to extubation

80. Khamiees M, Raju P, DeGirolamo A, et al. Predictors of extubation outcome in
patients who have successfully completed a spontaneous breathing trial. Chest 2001;
120:1262–1270.
• Brief period (12 to 24 hrs) of steroid therapy
prior to planned extubations, (in patients with
high risk of post-extubation laryngeal edema)
• A single dose of methylprednisolone (40 mg
IV) given 1 hour prior to extubation did not
reduce the incidence of post-extubation
laryngeal edema
• Thus there is no reason to administer
steroids only at the time of extubation.

81. Postextubation Stridor
 The first sign of a significant laryngeal obstruction
 High-pitched and wheezy, inspiratory prominence
 Reintubation is not always required
 No proven method for reducing laryngeal edema after
extubation.

82. Aerosolized Epinephrine
• Inhalation of aerosolised epinephrine (2.5 mL of 1%
epinephrine)
• Practice is unproven in adults.
• Found to be effective in children
• No advantage with racemic epinephrine over
standard (l-isomer) epinephrine

83. Noninvasive Ventilation
• Effective in reducing the rate of reintubation when
used immediately after extubation in patients with a
high risk of laryngeal edema
• No benefit in patients who develop post-extubation
respiratory failure.
• Benefit of NIV ventilation occurs when it is used as a
preventive measure early after extubation.

84. OTHER MODES OF VENTILATION
• NAVA (Neurally Adjusted Ventilatory Assist )
• Automatic Tube Compensation
• Proportional Assist Ventilation
• Adaptive Support Ventilation

85. Neurally Adjust Ventilatory Assist
(NAVA)
CNS
Phrenic nerve
Diaphragm excitation
Diaphragm contraction
Chest wall, lung & esophageal response
Airway pressure, flow, volume
CURREN
T
IDEAL
NAVA

86. NAVA
 Electrical activity of the diaphragm - Eadi
 Represents the patient's breathing effort
 Normal healthy adults EAdi < 10 uV
 Can assess : Respiratory drive
Synchrony
Unloading of respiratory muscles
Sinderby C, Nat Med 1999

87. ADAPTIVE SUPPORT VENTILATION
(ASV)
Advantages
 Provides Automated weaning
 Fewer human resources are needed at bedside
No trigger
PCV Spont < Target
PS/SIMV
Spont>
Target
PSV
Respiratory Rate

88. ROLE OF NIV
• Early weaning – failed SBT
• After conventional weaning to
prevent post extubation failure
• Respiratory failure post
extubation
R Chawla et al: Ind J Crit Care Med 2006

89. ROLE OF TRACHEOSTOMY
ADVANTAGES
Improved pt comfort
Effective airway
suctioning
Dec. airway resistance
Reduced dead space
Enhanced pt mobility
Improved speech
Ability to eat orally
DISADVANTAGES
Perioperative
complications
Late tracheal stenosis
Obstruction
Impaired swallowing
JE Heffner : Chest 2001; 120:477S– 481S

90. COMMON MISCONCEPTIONS ABOUT
TRACHEOSTOMY
 Early tracheostomy does not reduce the incidence
of VAP
 Early tracheostomy does not reduce mortality rate.
 Early tracheostomy reduces sedative requirements
and promote early mobilization
BEST TIME FOR TRACHEOSTOMY 7-14 DAYS
Terragni et al. Early vs. late tracheotomy for prevention of pneumonia in
mechanically ventilated adult ICU patients. JAMA 2010; 303:1483– 1489

91.  Liberate from ventilation
 SBT in any form
 Sedation,synchrony,
spontaneous breathing
 Daily SBT and PSV
equally effective, SIMV
least efficient for weaning
 Mechanical ventilation for
> 2 weeks : early
tracheostomy
TAKE HOME MESSAGE

92. Special thanks to:
Dr Gyaninder Pal Singh, Asst Professor
Department of Neuroanaesthesia
Dr Karan Madan, Asst Professor,
Department of Pulmonary Medicine
Dr Kavitha, Senior Resident
Department of Pulmonary Medicine
Dr Sryma Punjadath, Junior Resident
Department of Internal Medicine