Weaning from Mechanical Ventilation€¦ · Yet, invasive mechanical ventilation is associated with...

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Srinivas Samavedam MD, DNB, FRCP, FNB, EDIC,DHQM Director, Critical Care, Century Super Specialty Hospital Weaning from Mechanical Ventilation

Transcript of Weaning from Mechanical Ventilation€¦ · Yet, invasive mechanical ventilation is associated with...

Page 1: Weaning from Mechanical Ventilation€¦ · Yet, invasive mechanical ventilation is associated with risks and complications that prolong the duration of mechanical ventilation and

Srinivas SamavedamMD, DNB, FRCP, FNB, EDIC,DHQM

Director, Critical Care,

Century Super Specialty Hospital

Weaning from Mechanical Ventilation

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Background

In intubated patients, mechanical ventilation offers essential ventilatory support, while the respiratory system recovers from acute respiratory failure.

Yet, invasive mechanical ventilation is associated with risks and complications that prolong the duration of mechanical ventilation and increase the risk for death.

Safely weaning the patient from the ventilator as soon as possible is paramount.

Weaning process is a continuum lasting from intubation until hospital discharge.

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Consequences of inappropriate weaningDelayed

Airway trauma

VAP

Ventilator induced lung injury

DVT, GI bleed

Increased sedation

Premature

• Respiratory muscle fatigue

• Cardiorespiratory compromise

• Failed extubation

• Loss of airway protection

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Where is the main action?

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Classification - Weaning Process

Brochard : based on the ability to wean

Simple weaning: Patient tolerates first spontaneous breathing trial (SBT) and is successfully extubated (70% of all patients).

Difficult weaning: Patient fails to tolerate initial SBT, successful weaning requiring up to three SBTs or up to 7 days from first SBT.

Prolonged weaning: Patient fails at least three SBTs or takes more than 7 days after the first

SBT.

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Classification - Weaning

Weaning Success : absence of ventilatory support 48hr following extubation

Weaning Failure : Failed SBT Reintubation / resumption of ventilatory support following extubationDeath within 48 h following extubation

Weaning in progress : requiring NIV post extubation

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Weaning – Steps Determine readiness for weaning

Weaning parametersPhysiological parametersIndices

How to weanSedation managementModeProtocolised

Difficulty in weaning

Tracheostomy

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Readiness Testing

The patient’s capacity to breathe spontaneously is often underestimated.

Rapid weaning must be balanced against the risks of premature spontaneous breathing.

Objective assessments are favored because subjective, clinical judgment appears to be relatively inaccurate in assessing readiness.

Nevertheless, 30% of patients never satisfying objective readiness criteria can still be successfully weaned.

Only 5 predictors shown to have good predictive value

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Weaning Parameters

Has the primary pathology resolved??????

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Weaning Indices

Negative inspiratory force (maximal inspiratory pressure)

Minute ventilation

Respiratory frequency

Tidal volume

Frequency–tidal volume ratio ( f/VT)60-105

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Steps For Weaning

• Sedation Management

• Modes of weaning

Conventional modes

Advanced modes

SBT – Spontaneous breathing trial

• Protocolised weaning

• Post-extubation care and monitoring

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Modes Of Weaning

Conventional modes

• PS ventilation

• SIMV

• t – piece

PSV better than SIMV

Advanced modes

• ATC

• ASV

• PAV

• NAVA

Role of NIV in weaning

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Spontaneous Breathing Trial

The best way to determine suitability for discontinuation of mechanical ventilation is to perform a SBT

t piece trial

Pressure Support with PEEP

CPAP

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Failure Criteria Of SBTWeaning failure is defined as either the failure of SBT or the need for reintubation

within 48 h following extubation

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Weaning Failure – Causes Primary Pathology

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Non Invasive Ventilation As A Weaning Tool

In weaning, NIV has been studied for three different indications, which should be strictly separated

First, NIV has been used as an alternative weaning modality for patients who are intolerant of the initial weaning trial – stable COPD patients

Secondly, NIV has been used as a treatment option for patients who have been extubated but developed ARF within 48 hrs – Rescue therapy

Thirdly, NIV has been used as a prophylactic measure after extubation for patients who are at high risk for re intubation but who did not develop ARF

COPD patients , Patients with CAD / CHF , Post operative

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Criteria For Extubation Failure

RR > 25 breaths per minute for >2 hours

HR > 140 beats per minute or sustained increase or decrease >20%

Clinical signs of respiratory muscle fatigue or increased work of breathingSaO2 < 90%; PaO2 < 80 mmHg on FI,O2 > 0.50

Hypercapnia (PaCO2 > 45 mmHg or >20% from pre-extubation), pH <7.33

Worsening CNS status

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Contemporary approach

Use of advanced modes

Assessment of fluid balance

Assessment of diaphragmatic function

Assessment of right heart function

Nutritional augmentation

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Tricks of the trade

Prepare for weaning at the time of intubation

Choose the biggest possible tube

Avoid overloading the patient with fluids and nutrition

Don’t stress a recovering heart

Do not ignore acid base and electrolyte imbalances

Ask the patient!

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