LIBERATION“Judgement Call”

Dr Ikhwan bin Wan Mohd Rubi, MD (UKM)

Supervisor:Dr Mohd Ridhwan Mohd Noor

Outline

• Introduction• Weaning and its evolution• Classification of weaning• Principles, Assessment; Clinical and Objectives• Spontaneous Breathing Trial– Approach, protocol, criteria to pass

• Extubation, failed extubation• Role of NIV & also tracheostomy• Causes of failed SBT• Algorithm of weaning

Introduction

• MV is the defining event in ICU mx• A life saving intervention in acute resp failure

and other disease entities• The aim of ventilatory support is to unload the

patient’s respiratory pump

Why Wean early ???

Increased risk of

VAP

Increased ICU length

of stay

Increased hospital length

of stay

Increased morbidity &

mortality

Increased cost

Decreases the availability of

ICU beds

Can adversely affect the patient

outcome

• Major goal is actually to LIBERATE pts from MV as early as possible while AVOIDING premature weaning

Weaning

• Def: A process of transition/gradual withdrawal of MV support that transfers the WOB from ventilator to the patient– Removal of a necessary (short term) but potentially

damaging (prolonged) intervention as early as feasible

• This period may take many forms ranging from abrupt to gradual withdrawal from ventilatory support

• Goal is to facilitate effective spontaneous breathing while reducing ventilatory support

• BALANCE between reducing ventilatory support without increasing pt’s WOB to the point of fatigue and failure

• The process of reloading the respiratory pump

Weaning

Adequate ventilatory support(minimizing respiratory fatigue)

Minimizing support (increasing pt’s resp autonomy)

Not over assisting, but not to cause fatigue

Evolution of Weaning

• >than a decade ago, weaning from PPV was often a slow gradual process of reduction in ventilatory support (IMV)

• Introduction of SIMV mode and later PSV• Numerous studies have investigated methods

and tools for identifying readiness of mechanically ventilated pts for successful liberation from MV

Facts75% of mechanically ventilated patients are easy to be

weaned off the ventilator with simple process; Hall JB, Wood LDH: Liberation of the patient from mechanical

ventilation, JAMA 1987, 257: 1621-1628

10-15% patients require use of a weaning protocol over a period of 24-72 hours

5-10% require a gradual weaning over longer time

1% of patients become chronically dependent on ventilator

Classification of WeaningGroup/ category Definition

Simple weaning Patients who proceed from initiation of weaning to successful extubation on the first attempt without difficulty

Difficult weaning Patients who fail initial weaning and require up to three SBT or as long as 7 days from the first SBT to achieve successful weaning

Prolonged weaning Patients who fail at least three weaning attempts or require >7 days of weaningafter the first SBT

Classification of Patients According to the Weaning Process

Group Definition FrequencyICU mortality

Hospital mortality

(1)Simple weaning

Patients who proceed from initiation of weaning to successful extubation on the first attempt without difficulty

69% 5% 12%

(2) Difficult weaning

Patients who fail initial weaning and require up to three SBT or as long as 7 days from the first SBT to achieve successful weaning

16%

25%

(3) Prolonged weaning

Patients who fail at least three weaning attempts or require 7 days of weaning after the first SBT

15%

Boles, et al. Eur Respir J 2007

Principles

In Short

• Consider weaning ASAP• Consider weaning once underlying causes

resolved/improved• Evaluate early & at least daily• CNS/CVS/Resp(patency/protection) must intact

before extubation• Minimize/discontinue sedation for daytime SBT• UNLESS in irreversible underlying disease

When to begin the weaning process?

• Numerous trials performed to develop criteria for success weaning, however, not useful to predict when to begin the weaning

• Physicians must rely on clinical judgement• Consider when the reason for IPPV is stabilised and

the patient is improving and haemodynamically stable

• Daily screening may reduce the duration of MV and ICU cost

Schematic Representation of the Different Stages Occurring in aMechanically Ventilated Patient

Definition of the different stages, from initiation to mechanical ventilation to weaning

Stages Definitions

Treatment of ARF Period of care and resolution of the disorder that caused respiratory failure and prompted mechanical ventilation

Suspicion The point at which the clinician suspects the patient may be ready to begin the weaning process

Assessing readiness to wean Daily testing of physiological measures of readiness for weaning (NIF, fR/VT) to determine probability of weaning success

Spontaneous breathing trial Assessment of the patient’s ability to breathe spontaneously

Extubation Removal of the endotracheal tube

Reintubation Replacement of the endotracheal tube for patients who are unable to sustain spontaneous ventilation

Martin J. Tobin2001

Protocol Weaning is More Effective than No Protocol

• Numerous studies have demonstrated that protocol weaning decreases mechanical ventilation days.

• Vitacca AJRCCM 2001;164:225-30 • Henneman CCM 2001;29:297-03 • Kollef New Horizons 1998;6:52-60 • Kollef CCM 1997;25:567-74

• All studies utilized a daily screening and subsequent spontaneous breathing trial to test the patient’s potential for discontinuing mechanical ventilation.

• Compared with usual care, use of weaning protocols can reduce the duration ofi. mechanical ventilation by 25%ii. weaning duration by 78%iii. length of stay in intensive care unit by 10%

Assessment of readiness to wean

A Daily routine follow up should be done in every patient receiving mechanical ventilation and exploring the following condition

1. Clinical assessment2. Objective measures

i. Respiratory criteriaii. Cardiovascular criteriaiii. Neurological criteria

Clinical Assessment

1. Resolution of acute phase of disease for which patient was intubated; indication of mechanical ventilation is reversed

2. Adequate cough (subjective)3. Absence of excessive tracheobronchial

secretion; frequency of trachea suctioning; characteristic of secretion

Objective measures

1) Respiratory criteria (O2 and ventilation)i. Adequate O2; PaO2≥60mmHg on FiO2≤0.5 &

PEEP≤8cmH2Oii. No significant respiratory acidosis; pH and PaCO2

appropriate for patient’s baseline respiratory status

iii. RR <35breaths/miniv. Vt >5mls/kgv. MV <12l/min (<10-12)

Objective measures

2) Cardiovascular criteriai. HR <140/minii. BP normal with minimal or no vasopressor

support (i.e Dopamine <5mcg/kg/min)iii. No evidence of myocardial ischemia

Objective measures

3) Neurological criteriai. Pt is arousable or GCS ≥ 13

In isolation, none is highly predictiveIn cluster, acceptable high predictive capacityOnce deemed ready, proceed to SBT

Once ready, proceed to SBT

Spontaneous Breathing Trial (SBT)

• Conducted when – connected to ventilator – or being removed from ventilator (T piece)

1) SBT through ventilatori. Use PSV of 5-7cmH2O + low PEEP 5cmH2Oii. Patient’s safety is ensure, back up ventilation can

be provided if necessaryiii. Vt and RR can be monitored

Spontaneous Breathing Trial (SBT)

2) SBT through a T-piecei. Deliver O2 enriched gas at high flow rates

(greater than the pt’s ins flow rate) through the horizontal arm of the T-shaped circuit

ii. The advantage is the reduced WOB with the T-shaped circuit

Tobin. Principles and Practice of Mechanical Ventilation, McGraw-Hill, 1994, s1192

Weaning : Selecting an Approach!!!• Many studies have compared the different

methods of weaning

• Common conclusions are

No clear superiority exists between T-tube weaning and pressure support based weaning

SIMV is the least efficient technique of weaning

The best approach may be the one with which the clinician is most familiar and is based on a sound rationale

Cuff leak test

• Extubation failure- need for reintubation within 72hrs of extubation

• Increased Risk in advanced age, high severity of illness at ICU admission & extubation, preexisting chronic resp/CVS disease.

• Reintubation also increased morbidity and mortality

• Intensivist needs to identify pts at increased risk and be prepared to reinstitute ventilation early to prevent adverse outcome

• Good mentation, competent airway, minimal secretions, good respiratory muscle strength and adequate CVS reserve are ESSENTIAL for successful extubation

• Still no validated predictors to indicate extubation failure

• One need to be alert for extubation failure and intervene early to prevent further morbidity/mortality

Approach to difficult to wean patient

• Weaning failure; any one of:i. Failure SBTii. Reintubation/ resumption of ventilator within

48hrsiii. Death within 48hrs of extubation

If patient fails SBT:

• Increase ventilator setting to previously tolerated level or higher if necessary until pt stable again and wait 24hr before trying again

• Search thoroughly and systematically for potentially reversible aetiologies

• Use PSV as a weaning tool by gradually reducing PS by 2cmH2O once or twice a day as tolerated

• Once PS is reduced to a minimal level (10cmH2O), rpt SBT daily until pt can be successfully extubated

• Concept of nocturnal rest in conjunction with daytime resp ms training is important

Role of NIV in weaning

• As an alternative in weaning technique– Rationale: to facilitate earlier removal of ETT while

still allowing a progressive stepwise reduction of ventilator support

– Involves extubating the pt who has failed a SBT directly onto NIV (PS+CPAP)• ONLY in pt with good airway protection, strong cough

and minimal secretions

– In practice, NIV mainly used to facilitate weaning in COPD pts

• Prophylactic measure in pt with high risk for reintubation– CAREFULLY SELECTED pt (i.e postoperative pt-

abdominal/vascular surgery)

Role of NIV in weaning

Role of tracheostomy

• Must be considered:– In any pt deemed difficult to wean (pt who fail initial SBT

and required up to 3 SBTs or up to 7 days to pass a SBT– Certainly in all pt with prolonged wean

• Potential benefits: less sedative requirement, more secure airway, reduction in oropharyngeal trauma, prevention of VAP, reduction in WOB, earlier transition to oral feeding, improved pt’s comfort and communication

• Optimal timing; early or late??

Caused of failed SBT/weaning

Caused of failed SBT/weaning

Caused of failed SBT/weaning

Algorithm of weaning

This is a general guideline in ICU pt’s care of management. Care is revised to meet individual patient's needs.Today presentation DO NOT prohibit or impede the planned rapid weaning and extubation of patients.

Summary

• Prediction based on Clinical ‘gestalt’ frequently inaccurate, thus it is sound rationale to based clinical judgement along with objective weaning predictors in clinical decision making

• Following weaning protocol significantly reduce duration of MV

• Certain weaning parameters shows conflicting results; not sufficiently accurate for liberation decision-making

• Successful liberation depends on the application of skilled judgement, decision making, and medical/nursing interventions

THANK YOU