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Weaning Modes and Protocol

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Weaning Modes and Protocol 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 ... – PowerPoint PPT presentation

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Title: Weaning Modes and Protocol


1
Weaning Modesand 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
2
4
Causes of Ventilator Dependence
  • Who is the ventilator dependent?
  • Mechanical ventilation gt 24 h
  • or
  • Failure to respond during discontinuation attemps

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
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

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.

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
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
Frequency of Tolerating an SBT in Selected
Patients and Rate of Permanent Ventilator
DiscontinuationFollowing a Successful SBT
Spontaneous Breathing Trial
Values given as No. (). Pts patients. 30-min
SBT. 120-min SBT.
15
Do Not Wean To Exhaustion
16
Weaning to Exhaustion
  • RR gt 35/min
  • Spo2 lt 90
  • HR gt 140/min
  • Sustained 20 increase in HR
  • SBP gt 180 mm Hg, DBP gt 90 mm Hg
  • Anxiety
  • Diaphoresis

17
Mechanical Ventilation
Low level CPAP (5 cm H2O), Low levels of
pressure support (5 to 7 cm H2O) T-piece
breathing
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
  • 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

20
Post Extubation Stridor
Extubation Criteria
  • 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

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
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

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

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

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

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

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 24-72 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 lt 30
  • Minute ventilation of lt 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
Predictor Value
Evaluation of ventilatory drive P 0.1 lt 6 cm H2O
Ventilatory muscle capability Vital capacity Maximum inspiratory pressure gt 10 mL/kg lt -30 cm H2O
Ventilatory performance Minute ventilation Maximum voluntary ventilation Rapid shallow breathing index Respiratory rate lt 10 L/min gt 3 times VE lt 105 lt 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/Vtgt105 95 wean attempts unsuccessful
  • RR/Vtlt105 80 successful
  • One of the most predictive bedside parameters.

50
Measurements Performed Either While Patient Was
Receiving Ventilatory Support or During a
BriefPeriod of Spontaneous Breathing That Have
Been Shown to Have Statistically Significant LRs
To Predict theOutcome of a Ventilator
Discontinuation Effort in More Than One Study
51
Weaning to Exhaustion
  • RR gt 35/min
  • Spo2 lt 90
  • HR gt 140/min
  • Sustained 20 increase in HR
  • SBP gt 180 mm Hg, DBP gt 90 mm Hg
  • Anxiety
  • Diaphoresis

52
Work-of-Breathing
  • 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
0
-5
-5
55
0
Auto PEEP 10
-5
-15
56
PEEP 10
Auto PEEP 10
5
-5
57
Preparation Factors Affecting Ventilatory Demand
58
(No Transcript)
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 lt 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
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