SEMINAR ON SEMINAR ON MECHANICAL VENTILATIONMECHANICAL VENTILATION

GuideGuide

Dr. G.Singh (MS)Dr. G.Singh (MS)

Co-Guide Co-Guide

Dr. A.M. Lakra (MD)Dr. A.M. Lakra (MD)

-Rajan Kumar

IntroductionIntroduction

Cornerstone for intensive care medicineCornerstone for intensive care medicine Ventilate is derived from Latin word Ventilate is derived from Latin word

“ventus”“ventus” meaning meaning wind.wind. VentilationVentilation is movement of  is movement of airair into and outside  into and outside

the body the body The ventilators must overcome the The ventilators must overcome the

pressure generated by the elastic recoil of pressure generated by the elastic recoil of the lung at end inspiration plus the the lung at end inspiration plus the resistance to flow at the airway.resistance to flow at the airway.

Ventilators provide infusion of a blend of air Ventilators provide infusion of a blend of air or oxygen into the circuit.or oxygen into the circuit.

HistoryHistory

In In 1543, Vesalius1543, Vesalius demonstrated the ability to demonstrated the ability to maintain the beating heart in animals with open maintain the beating heart in animals with open chest.chest.

In In 1780,1780, such technique were first applied to such technique were first applied to humanshumans

In In 1887, fell-o-dwyer apparatus1887, fell-o-dwyer apparatus was used for was used for translaryngeal ventilation via a bellows.translaryngeal ventilation via a bellows.

In In 1928, the drinker–Shaw iron lung1928, the drinker–Shaw iron lung based on based on negative pressure ventilationnegative pressure ventilation

From From 1930-19501930-1950 – such machines were the – such machines were the mainstay in ventilation of mainstay in ventilation of victims of poliovictims of polio epidemicsepidemics

Basic anatomyBasic anatomy

Respiratory physiologyRespiratory physiology

Tidal volumeTidal volume Respiratory rateRespiratory rate Minute volumeMinute volume Inspiratory Reserve VolumeInspiratory Reserve Volume Expiratory Reserve VolumeExpiratory Reserve Volume Inspiratory Capacity (IRV + TV)Inspiratory Capacity (IRV + TV) Residual VolumeResidual Volume Functional Residual Capacity (ERV + RV)Functional Residual Capacity (ERV + RV) Vital capacity (IRV + TV + ERV)Vital capacity (IRV + TV + ERV) Total Lung Capacity (IRV + TV + ERV + RV)Total Lung Capacity (IRV + TV + ERV + RV) ComplianceCompliance Dead spaceDead space

MECHANICAL VENTILATORMECHANICAL VENTILATOR

Ventilators are Ventilators are specially designed pumpsspecially designed pumps that can support the ventilatory function of that can support the ventilatory function of the respiratory system and improve the respiratory system and improve oxygenation through application of high oxygenation through application of high oxygen content gas and positive pressure.oxygen content gas and positive pressure.

ComponentsComponents

Bacterial filterBacterial filter Pneumotachometer, valves & solenoidsPneumotachometer, valves & solenoids HumidifierHumidifier Heater/ thermostatHeater/ thermostat Oxygen analyserOxygen analyser Pressure manometerPressure manometer Chamber for nebulising drugChamber for nebulising drug CompressorCompressor BatteryBattery

GoalsGoals

Achieve and maintain adequate pulmonary gas Achieve and maintain adequate pulmonary gas

exchange exchange

Minimise the risk of lung injuryMinimise the risk of lung injury

Reduce patient work of breathingReduce patient work of breathing

Optimise patient comfortOptimise patient comfort

ClassificationClassification

1. 1. ICU VentilatorsICU Ventilators

The condition of lung is poorThe condition of lung is poor

2. 2. Anaesthetic ventilatorsAnaesthetic ventilators

The condition of lung is goodThe condition of lung is good

3. 3. Transport ventilatorTransport ventilator

The ventilator is compact and used for transportation of The ventilator is compact and used for transportation of

victim/patients from one site to othervictim/patients from one site to other

4. 4. Other/specialOther/special

(a) (a) High frequency ventilatorHigh frequency ventilator

(i) High frequency positive pressure ventilator(i) High frequency positive pressure ventilator

(ii) High frequency jet ventilator(ii) High frequency jet ventilator

(iii) High frequency oscilitation ventilator (iii) High frequency oscilitation ventilator

ICU ventilatorICU ventilator

A. A. Positive pressure ventilation (PPV)Positive pressure ventilation (PPV)

(a) Non invasive PPV(a) Non invasive PPV

(i) Nasal mask(i) Nasal mask

(ii) Facial mask(ii) Facial mask

These has less complications and as effective as invasive These has less complications and as effective as invasive

ventilators ventilators

(b) Invasive PPV(b) Invasive PPV

(i) Nasotracheal tube(i) Nasotracheal tube

(ii) Oro tracheal tube(ii) Oro tracheal tube

(iii) Tracheostomy(iii) Tracheostomy

B.Negative pressure ventilationB.Negative pressure ventilation

Iron lung machineIron lung machine

The machine creates a negative pressure to expand the The machine creates a negative pressure to expand the

chest wall so that the lungs can expand inside it with the chest wall so that the lungs can expand inside it with the

negative intrapleural pressure.negative intrapleural pressure.

Ventilator cycleVentilator cycle

pausepause

pausepause

inspirationinspiration

expirationexpiration

PrinciplesPrinciples

– Gas flows only down the pressure gradient, Gas flows only down the pressure gradient, i.e. from areas of high pressure to low i.e. from areas of high pressure to low pressure.pressure.

– Exhalation is a passive process, ventilators Exhalation is a passive process, ventilators expend energy only during inhalationexpend energy only during inhalation

– Mechanical ventilation is produced through the Mechanical ventilation is produced through the interaction of only 5 variablesinteraction of only 5 variables

1.1.Time Time

2.2.VolumeVolume

3.3.PressurePressure

4.4. inspiratory: expiratory (I:E) ratio inspiratory: expiratory (I:E) ratio

5.5.FlowFlow

ObjectivesObjectives

Improve O2 &CO2 gas exchangeImprove O2 &CO2 gas exchange

– Reverse hypoxemiaReverse hypoxemia

– Prevent progressive hypercapniaPrevent progressive hypercapnia

– Reverse acute respiratory acidosisReverse acute respiratory acidosis

Improve ventilation distributionImprove ventilation distribution

– Prevent and reverse lung collapse Prevent and reverse lung collapse

– Reduce venous admixtureReduce venous admixture

Assist respiratory muscleAssist respiratory muscle– Decreased O2 cost of breathing Decreased O2 cost of breathing – Relieve resp. distress Relieve resp. distress

Improve lung complianceImprove lung compliance– Increase alveolar recruitmentIncrease alveolar recruitment

- Return lung to resting lung volumes- Return lung to resting lung volumes

IndicationsIndications

On the basis of blood gas analysisOn the basis of blood gas analysis

1. PO2 <50mmHg on room air1. PO2 <50mmHg on room air

<60mmHg on oxygen support (FIO2 >50%)<60mmHg on oxygen support (FIO2 >50%)

2. PCO2 >50mmHg2. PCO2 >50mmHg

3. pH <7.253. pH <7.25

4. PO2/FIO2 <250mmHg 4. PO2/FIO2 <250mmHg

5. p (A-a ) O2 gradient >350 mmHg on 100% O2.5. p (A-a ) O2 gradient >350 mmHg on 100% O2.

On the basis of pulmonary functionOn the basis of pulmonary function

1.1. Resp. Rate >35/minResp. Rate >35/min

2.2. Vital capacity <15ml/kgVital capacity <15ml/kg

3.3. Dead space volume (VD/VT) >0.6 (60%)Dead space volume (VD/VT) >0.6 (60%)

4.4. Tidal volume <5ml/kgTidal volume <5ml/kg

Basic physics related to Basic physics related to mechanical ventilationmechanical ventilation

Paw = flow× resistance + volume ∕ compliance + PEEPPaw = flow× resistance + volume ∕ compliance + PEEP

Pressure at point B is equivalent to the alveolar pressure and is determined by Pressure at point B is equivalent to the alveolar pressure and is determined by the volume inflating the alveoli divided by the compliance of the alveoli plus the the volume inflating the alveoli divided by the compliance of the alveoli plus the baseline pressure (PEEP).baseline pressure (PEEP).

Pressure at point A (equivalent to airway pressure measured by the ventilator) Pressure at point A (equivalent to airway pressure measured by the ventilator) is the sum of the product of flow and resistance due to the tube and pressure at is the sum of the product of flow and resistance due to the tube and pressure at point B.point B.

Flow, volume and pressure are variables while resistance Flow, volume and pressure are variables while resistance

and compliance are constants.and compliance are constants.

It follows from the relationship between pressure, flow and It follows from the relationship between pressure, flow and

volume that by setting one of pressure, volume or flow and volume that by setting one of pressure, volume or flow and

the pattern in which it is delivered which includes the time the pattern in which it is delivered which includes the time

over which it is delivered the other two become constants.over which it is delivered the other two become constants.

It also follows that it is not possible to present more than It also follows that it is not possible to present more than

one of these variables at a time.one of these variables at a time.

Components of Inflation Pressure

Components of Inflation Pressure

Begin InspirationBegin Inspiration Begin ExpirationBegin Expiration

11

22

BBAA

1. PIP 1. PIP 2. 2. PPplatplat/Alveolar Pressure/Alveolar PressureA. Airway ResistanceA. Airway ResistanceB. Distending PressureB. Distending Pressure

Time (sec)Time (sec)

PPawaw

(cm H(cm H22O)O)

Components of Inflation Pressure

Components of Inflation Pressure

Begin InspirationBegin Inspiration Begin ExpirationBegin Expiration

11

22

BBAA

1. PIP 1. PIP 2. 2. PPplatplat/Alveolar Pressure/Alveolar PressureA. Airway ResistanceA. Airway ResistanceB. Distending PressureB. Distending Pressure

Time (sec)Time (sec)

PPawaw

(cm H(cm H22O)O)

CyclingCycling

Time cycledTime cycled Pressure cycledPressure cycled Volume cycledVolume cycled

Time cycledTime cycled – these cycle to expiration once a – these cycle to expiration once a predetermined time is elapsed since inspiration.predetermined time is elapsed since inspiration.

Tidal volume is determined by set inspiratory flow Tidal volume is determined by set inspiratory flow and inspiratory timeand inspiratory time

Used in Used in – Operation theatersOperation theaters– In neonatesIn neonates

Pressure cycledPressure cycled

These cycled to expiration once a predetermined pressure These cycled to expiration once a predetermined pressure

is reached, so if there is leak in circuit the predetermined is reached, so if there is leak in circuit the predetermined

pressure will not reached and pt. will remain in inspiration pressure will not reached and pt. will remain in inspiration

conversely, if airway pressure is high, bronchospasm or conversely, if airway pressure is high, bronchospasm or

tube kinking there will be premature end of inspiration and tube kinking there will be premature end of inspiration and

patient can be hypoventilated. patient can be hypoventilated.

Volume cycledVolume cycled – Inspiration is terminated when a preset – Inspiration is terminated when a preset

tidal volume is delivered.tidal volume is delivered.

So theoretically, the patient cannot be hypoventilated even So theoretically, the patient cannot be hypoventilated even

if the lung compliance (airway pressure) changes but if the lung compliance (airway pressure) changes but

actually this is not the case, a portion of tidal volume is lost actually this is not the case, a portion of tidal volume is lost

(120-150ml) in the ventilator breathing circuit and if (120-150ml) in the ventilator breathing circuit and if

patient’s pulmonary compliance is decreased (peak patient’s pulmonary compliance is decreased (peak

inhalation pressure will increase) the delivered tidal volume inhalation pressure will increase) the delivered tidal volume

can further be decreased.can further be decreased.

The accurate, tidal volume reaching to patients can only be calculated by The accurate, tidal volume reaching to patients can only be calculated by

putting a spirometer at the endotracheal tube.putting a spirometer at the endotracheal tube.

e.g. most commonly used in ICUs e.g. most commonly used in ICUs

Disadvantage – they deliver fixed tidal volume so if airway pressure Disadvantage – they deliver fixed tidal volume so if airway pressure

becomes high and still same tidal volume is be delivered the chances of becomes high and still same tidal volume is be delivered the chances of

barotrauma are increased.barotrauma are increased.

Dual controlDual control – can work in both volume control and pressure control – can work in both volume control and pressure control

mode and can switch over from one mode to other depending on mode and can switch over from one mode to other depending on

requirements.requirements.

Modes of mechanical Modes of mechanical ventilationsventilations

Characterized by three variables Characterized by three variables

The parameter used to initiate or ‘The parameter used to initiate or ‘triggertrigger’ a breath’ a breath

The parameter used to ‘The parameter used to ‘limitlimit’ the size of breath, ’ the size of breath,

andand

the parameter used to terminate inspiration or the parameter used to terminate inspiration or

‘‘cyclecycle’ the breath.’ the breath.

In In controlled ventilationcontrolled ventilation modesmodes – time triggered Inspiratory – time triggered Inspiratory

phase is concluded once a desired volume, pressure or flow phase is concluded once a desired volume, pressure or flow

is attained but the expiratory time (Et) will form the difference is attained but the expiratory time (Et) will form the difference

between the inspiratory time (It) and the preset respiratory between the inspiratory time (It) and the preset respiratory

cycle time.cycle time.

In In Assist modeAssist mode – the ventilator is pressure or flow triggered – the ventilator is pressure or flow triggered

The magnitude of the breath is controlled or limited by one of The magnitude of the breath is controlled or limited by one of

three variablesthree variables

Volume, pressure or flow.Volume, pressure or flow.

Controlled mode ventilation(CMV)/ intermittent positive pressure ventilation (IPPV):Controlled mode ventilation(CMV)/ intermittent positive pressure ventilation (IPPV):

in this mode patient’s own effort is nil. Only ventilator is delivering the preset tidal volume at in this mode patient’s own effort is nil. Only ventilator is delivering the preset tidal volume at

preset frequencypreset frequency

Assist controlled ventilation(AC):Assist controlled ventilation(AC): in this mode assist means the ventilator in this mode assist means the ventilator

supplementation of patient initiated breath (which itself doesnot have adequate tidal supplementation of patient initiated breath (which itself doesnot have adequate tidal

volume) and control means back up rate which is set up by clinician.volume) and control means back up rate which is set up by clinician.

Synchronized intermittent mandatory ventilation (SIMVSynchronized intermittent mandatory ventilation (SIMV): in this mode ventilator will deliver ): in this mode ventilator will deliver only between patient’s efforts or to coincide with the beginning of spontaneous effort.only between patient’s efforts or to coincide with the beginning of spontaneous effort.

Advantages of SIMVAdvantages of SIMV over CMV over CMV1.1. Less haemodynamic depressionLess haemodynamic depression2.2. Patient on CMV/IPPV need heavy sedation or muscle relaxant.Patient on CMV/IPPV need heavy sedation or muscle relaxant.3.3. Less V/Q mismatchLess V/Q mismatch4.4. No sense of breathlessness between ventilatory cyclesNo sense of breathlessness between ventilatory cycles5.5. More rapid weaningMore rapid weaning

DisadvantagesDisadvantages

1.increased work of breathing can cause muscular fatigue.1.increased work of breathing can cause muscular fatigue.

2.increased chances of hypocapnia (due to hyperventilation)2.increased chances of hypocapnia (due to hyperventilation)

Positive end expiratory pressure (PEEP)Positive end expiratory pressure (PEEP) indicationsindications

pulmonary edemapulmonary edema

ARDSARDS

In thoracic surgery to minimize postoperative bleeding.In thoracic surgery to minimize postoperative bleeding.

Physiological PEEP (in normal intubated patient to prevent Physiological PEEP (in normal intubated patient to prevent

atelectasis)atelectasis)

Mechanism of PEEPMechanism of PEEP Positive pressure given at end expiration prevents alveoli to collapse and small airways to close. So more time is available Positive pressure given at end expiration prevents alveoli to collapse and small airways to close. So more time is available

for gaseous exchangefor gaseous exchange Side effectsSide effects of PEEP of PEEP1.1. Hypotension and decrease in cardiac output: PEEP compresses venules in alveolar septa leading to decreased venous Hypotension and decrease in cardiac output: PEEP compresses venules in alveolar septa leading to decreased venous

return. So optimal PEEP is the value which maintain oxygen saturation >90% without decreasing the cardiac output return. So optimal PEEP is the value which maintain oxygen saturation >90% without decreasing the cardiac output significantly.significantly.

2.2. Increased pulmonary artery pressure and right ventricular strain: it is due to compression of capillaries in alveolar septa.Increased pulmonary artery pressure and right ventricular strain: it is due to compression of capillaries in alveolar septa.3.3. Increased dead space because of overdistension of normal alveoli.Increased dead space because of overdistension of normal alveoli.4.4. Increased pleural and mediastinal pressure.Increased pleural and mediastinal pressure.5.5. These increased pressures can cause pulmonary barotrauma These increased pressures can cause pulmonary barotrauma

Inverse ratio ventilation (IRV):Inverse ratio ventilation (IRV): ratio of inspiration to ratio of inspiration to expiration is reversed(2:1, while normal ratio is 1:2). expiration is reversed(2:1, while normal ratio is 1:2). Prolonged inspiration will maintain positive pressure. So Prolonged inspiration will maintain positive pressure. So more or less it acts like PEEP. It is better than PEEP and more or less it acts like PEEP. It is better than PEEP and there is even distribution of ventilation.there is even distribution of ventilation.

Pressure support ventilation (PSVPressure support ventilation (PSV): if a patient is on ): if a patient is on spontaneous respiration with adequate frequency but not spontaneous respiration with adequate frequency but not adequate tidal volume,this mode is helpful in increasing adequate tidal volume,this mode is helpful in increasing the tidal volume.the tidal volume.

Pressure controlled ventilation (PCV):Pressure controlled ventilation (PCV): in this mode in this mode

pressure is preset and ventilator terminates inspiration once pressure is preset and ventilator terminates inspiration once

preset pressure is achieved. So if airway pressure varies preset pressure is achieved. So if airway pressure varies

patient is prone for ventilation but advantage is that chances patient is prone for ventilation but advantage is that chances

of barotrauma is less and there is choice of extending of barotrauma is less and there is choice of extending

inspiratory time, facilitating better oxygen.inspiratory time, facilitating better oxygen.

BIPAPBIPAP: bipap means positive pressure both during : bipap means positive pressure both during inspiration and expiration. Typical setting is 8-20 cm H2O inspiration and expiration. Typical setting is 8-20 cm H2O positive pressure during inspiration and 5 cm H2O during positive pressure during inspiration and 5 cm H2O during expiration.it is combination of PSV and PEEP.expiration.it is combination of PSV and PEEP.

Airway pressure release ventilation (APRV)Airway pressure release ventilation (APRV) applied to applied to patient on CPAP where there is periodic release of patient on CPAP where there is periodic release of CPAP to decrease the incidence of barotrauma and CPAP to decrease the incidence of barotrauma and hypotension.hypotension.

High frequency ventilationHigh frequency ventilation: this mode is : this mode is

applicable in conditions in which adequate tidal applicable in conditions in which adequate tidal

volume cannot be delivered. So minute volume is volume cannot be delivered. So minute volume is

maintained by high frequency.maintained by high frequency.

TYPES OF WAVES FORMSTYPES OF WAVES FORMS

Pressure waveformsPressure waveforms– Rectangular Rectangular – Exponential riseExponential rise– Sine Sine

Volume waveformsVolume waveforms– Ascending rampAscending ramp– SinusoidalSinusoidal

Flow waveformsFlow waveforms– RectangularRectangular– SinusoidalSinusoidal– Ascending rampAscending ramp– Descending rampDescending ramp– Exponential decayExponential decay

Flow PatternsFlow Patterns

ACCELERATINGACCELERATING

DECELERATINGDECELERATING

SINESINE

SQUARESQUARE

Flow PatternsFlow Patterns

ACCELERATINGACCELERATING

DECELERATINGDECELERATING

SINESINE

SQUARESQUARE

Setting of ventilatorSetting of ventilator

Tidal volumeTidal volume I:E ratioI:E ratio FrequencyFrequency PEEPPEEP Trigger sensitivity (for Trigger sensitivity (for

assist mode) assist mode) FIO2FIO2

5-7 ml/kg5-7 ml/kg

1:21:2

10-12 bpm10-12 bpm

3–5 cmH2O3–5 cmH2O

-1 to -2 cmH2O-1 to -2 cmH2O

50%50%

Normal ABG ValuesNormal ABG Values

pHpH PaCO2PaCO2 PaO2PaO2 SaO2SaO2 HCO3HCO3¯̄ Base excessBase excess

7.35 - 7.457.35 - 7.45

35 – 45 mmHg35 – 45 mmHg

70 – 100 mmHg70 – 100 mmHg

93 - 98%93 - 98%

22 – 26 mEq/L22 – 26 mEq/L

-2.0 to 2.0 mEq/L-2.0 to 2.0 mEq/L

Ventilator parameters adjustment Ventilator parameters adjustment according to blood gasesaccording to blood gases

GoalsGoals PIPPIP PEEPPEEP RATERATE FiO2FiO2 TiTi

PCO2PCO2 ________ ________

PCO2PCO2 ________ ________

PO2PO2 __________

PO2PO2 __________

MonitoringMonitoring

Clinical Clinical

RadiologicalRadiological

BiochemicalBiochemical

BacteriologicalBacteriological

othersothers

Clinical monitoringClinical monitoring

General AppearanceGeneral Appearance Level of activityLevel of activity Response to stimulusResponse to stimulus Eye openingEye opening PosturePosture PerfusionPerfusion ColorColor EdemaEdema

Movement of chestMovement of chest

Retractions Retractions

SynchronizationSynchronization

Air entryAir entry

Adequacy of mechanical breathAdequacy of mechanical breath

Pulse oximetryPulse oximetry

EtCO2 monitoringEtCO2 monitoring

ABG analysisABG analysis

Capillary gas determinationCapillary gas determination

Transcutaneous monitoringTranscutaneous monitoring

Oxygenation indicesOxygenation indices

Monitoring of O2 & CO2 statusMonitoring of O2 & CO2 status

Ventilator ParametersVentilator Parameters PIPPIP PEEPPEEP MAPMAP RRRR Ti & I:E RatioTi & I:E Ratio FiO2FiO2 VTVT Trends of Ventilator ParametersTrends of Ventilator Parameters Pulmonary GraphicsPulmonary Graphics

Hemodynamic StabilityHemodynamic Stability

OxygenationOxygenation

Adequacy of CirculationAdequacy of Circulation

Radiological MonitoringRadiological Monitoring

When to do Chest X-ray ?When to do Chest X-ray ?

At the start of ventilationAt the start of ventilation

Before surfactant administrationBefore surfactant administration

After ET tube changeAfter ET tube change

Sudden deteriorationSudden deterioration

Prior to extubationPrior to extubation

Post extubationPost extubation

Biochemical MonitoringBiochemical Monitoring

Blood GasesBlood Gases

Blood SugarBlood Sugar

Serum calciumSerum calcium

Serum electrolytesSerum electrolytes

Bacteriological MonitoringBacteriological Monitoring

Blood cultureBlood culture

ET tube cultureET tube culture

Other MonitoringOther Monitoring

Humidification & warming of ventilator circuit gasesHumidification & warming of ventilator circuit gases

Position of patientPosition of patient

SkinSkin

Fluid & electrolytesFluid & electrolytes

Nutrition statusNutrition status

SensoriumSensorium

Infection controlInfection control

Sedation in Mechanically Sedation in Mechanically Ventilated PatientsVentilated Patients

BenzodiazepinesBenzodiazepines OpioidsOpioids NeurolepticsNeuroleptics PropofolPropofol KetamineKetamine DexmedetomidineDexmedetomidine

Maintenance of SedationMaintenance of Sedation

Titrate dose to ordered scaleTitrate dose to ordered scale– Motor Activity Assessment Scale Motor Activity Assessment Scale MAASMAAS– Sedation-Agitation Scale Sedation-Agitation Scale SASSAS– Modified Ramsay Sedation ScaleModified Ramsay Sedation Scale

Rebolus prior to all increases in the Rebolus prior to all increases in the maintenance infusionmaintenance infusion

Daily interruption of sedationDaily interruption of sedation

NEUROMUSCULAR NEUROMUSCULAR BLOCKING AGENTSBLOCKING AGENTS

Difficult to asses adequacy of sedationDifficult to asses adequacy of sedation Polyneuropathy of the critically illPolyneuropathy of the critically ill Use if unable to ventilate patient after Use if unable to ventilate patient after

patient adequately sedatedpatient adequately sedated Have no sedative or analgesic propertiesHave no sedative or analgesic properties

TroubleshootingTroubleshooting Is it working ?Is it working ?

–Look at the patient !!Look at the patient !!–Listen to the patient !!Listen to the patient !!– Pulse Ox, ABG, EtCOPulse Ox, ABG, EtCO22

– Chest X rayChest X ray– Look at the vent (PIP; expired TV; Look at the vent (PIP; expired TV;

alarms)alarms)

TroubleshootingTroubleshooting

When in doubt, DISCONNECT THE When in doubt, DISCONNECT THE PATIENT FROM THE VENT, and begin bag PATIENT FROM THE VENT, and begin bag ventilation.ventilation.

Ensure you are bagging with 100% O2.Ensure you are bagging with 100% O2. This eliminates the vent circuit as the source This eliminates the vent circuit as the source

of the problem.of the problem. Bagging by hand can also help you gauge Bagging by hand can also help you gauge

patient’s compliancepatient’s compliance

TroubleshootingTroubleshooting

Airway first: is the tube still in? (may need Airway first: is the tube still in? (may need DL/EtCO2 to confirm) Is it patent? Is it in the DL/EtCO2 to confirm) Is it patent? Is it in the right position?right position?

Breathing next: is the chest rising? Breath Breathing next: is the chest rising? Breath sounds present and equal? Changes in sounds present and equal? Changes in exam? Atelectasis, bronchospasm, exam? Atelectasis, bronchospasm, pneumothorax, pneumonia? (Consider pneumothorax, pneumonia? (Consider needle thoracentesis)needle thoracentesis)

Circulation: shock? Sepsis?Circulation: shock? Sepsis?

TroubleshootingTroubleshooting

Well, it isn’t working…..Well, it isn’t working…..– Right settings ? Right Mode ?Right settings ? Right Mode ?– Does the vent need to do more work ?Does the vent need to do more work ?

Patient unable to do soPatient unable to do so Underlying process worsening (or new problem?) Underlying process worsening (or new problem?)

– Air leaks?Air leaks?– Does the patient need to be more sedated ?Does the patient need to be more sedated ?– Does the patient need to be extubated ?Does the patient need to be extubated ?

TroubleshootingTroubleshooting

Patient - Ventilator InteractionPatient - Ventilator Interaction– Vent must recognize patient’s respiratory efforts Vent must recognize patient’s respiratory efforts

(trigger)(trigger)– Vent must be able to meet patient’s demands Vent must be able to meet patient’s demands

(response)(response)– Vent must not interfere with patient’s efforts Vent must not interfere with patient’s efforts

(synchrony)(synchrony)

TroubleshootingTroubleshooting

Improving Ventilation and/or OxygenationImproving Ventilation and/or Oxygenation– can increase respiratory rate (or decrease rate if can increase respiratory rate (or decrease rate if

air trapping is an issue)air trapping is an issue)– can increase tidal volume/PAP to increase tidal can increase tidal volume/PAP to increase tidal

volumevolume– can increase PEEP to help recruit collapsed can increase PEEP to help recruit collapsed

areasareas– can increase pressure support and/or decrease can increase pressure support and/or decrease

sedation to improve patient’s spontaneous effortsedation to improve patient’s spontaneous effort

Trouble ShootingTrouble Shooting

Ventilator alarms Ventilator alarms

Airway pressureAirway pressure

-high/low-high/low Tidal volume Tidal volume Inspiratory flow Inspiratory flow Expiratory flow Expiratory flow Triggering Triggering FiO2FiO2

Weaning from ventilatorWeaning from ventilator

It means discontinuing the ventilatory support.It means discontinuing the ventilatory support.

Guidelines are:Guidelines are:

1. pO2 >60 mm Hg (or oxygen saturation > 1. pO2 >60 mm Hg (or oxygen saturation > 90%) on FIO2 <50% and PEEP <5mmHg.90%) on FIO2 <50% and PEEP <5mmHg.

2. pCo2 <50 mmHg2. pCo2 <50 mmHg

3. Respiratory rate <20/min3. Respiratory rate <20/min

4. Vital capacity >15ml/kg4. Vital capacity >15ml/kg

5. VD/VT <0.65. VD/VT <0.6

6. Tidal volume > 5ml/kg6. Tidal volume > 5ml/kg

7. Minute ventilation <10 litres/min7. Minute ventilation <10 litres/min 8. Inspiratory pressure <-30 cm H2O8. Inspiratory pressure <-30 cm H2O 9. rapid shallow breathing index (RSBI) should be <1009. rapid shallow breathing index (RSBI) should be <100 = respiratory rate (breaths/min)/tidal volume (in = respiratory rate (breaths/min)/tidal volume (in

litres)litres) 10. Arterial pH is normal10. Arterial pH is normal 11. Normal cardiac status11. Normal cardiac status 12. Normal electrolytes12. Normal electrolytes 13. Adequate nutritional status13. Adequate nutritional status

Method of weaningMethod of weaning

Although weaning process vary from patient to patient and is Although weaning process vary from patient to patient and is

possible to wean patient in any mode of ventilation except control possible to wean patient in any mode of ventilation except control

mode ventilationmode ventilation

Pulmonary barotraumaPulmonary barotrauma

PneumothoraxPneumothorax

PneumomediastinumPneumomediastinum

Bronchopleural fistulaBronchopleural fistula

PneumocardiumPneumocardium

Air embolismAir embolism

ComplicationsComplications

infectioninfection

Pulmonary (ventilator assoc. pneumonia)Pulmonary (ventilator assoc. pneumonia)

Urinary Urinary

Wound infectionWound infection

iv cannula relatediv cannula related

complications due to prolonged intubationcomplications due to prolonged intubation

Airway edemaAirway edema

Sore throatSore throat

Laryngeal ulcer and granulomaLaryngeal ulcer and granuloma

GITGIT

1.1. stress ulcerstress ulcer

2.2. paralytic ileusparalytic ileus

cardiovascular:cardiovascular: right ventricular strain or even rt ventricular failure right ventricular strain or even rt ventricular failure

nosocomial infectionsnosocomial infections

liver and kidney dysfunctionliver and kidney dysfunction due to decreased cardiac output due to decreased cardiac output

neuromuscular weaknessneuromuscular weakness

ciliary activity impairmentciliary activity impairment

oxygen toxicityoxygen toxicity

prolonged immobilizationprolonged immobilization

bed sores, thromboembolismbed sores, thromboembolism

Acute Deterioration - DOPEAcute Deterioration - DOPE

Displaced tubeDisplaced tube

Obstructed Tube ( blocked tube)Obstructed Tube ( blocked tube)

PneumothoraxPneumothorax

Equipment FailureEquipment Failure

Gradual DeteriorationGradual Deterioration

Increase in primary pathologyIncrease in primary pathology InfectionInfection AnemiaAnemia Hypo tensionHypo tension DyselectrolytemiaDyselectrolytemia HypoglycemiaHypoglycemia Progression to CLDProgression to CLD

CARE OF THE PATIENT ON CARE OF THE PATIENT ON VENTILATORVENTILATOR

Care of unconscious patientCare of unconscious patient SedationSedation AnalgesiaAnalgesia Care of conscious patientCare of conscious patient Care of all vascular lines and tubesCare of all vascular lines and tubes Nutritional supportNutritional support

Respiratory careRespiratory care Care of ET Tube/Tracheostomy TubeCare of ET Tube/Tracheostomy Tube AntibioticAntibiotic BronchodilatorsBronchodilators MucolyticMucolytic PhysiotherapyPhysiotherapy

- chest- chest

- limb- limb Humidification/ warming of airwayHumidification/ warming of airway Prevention of aspirationPrevention of aspiration

TAKE HOME MESSAGETAKE HOME MESSAGE

Learned by surgical residentLearned by surgical resident

Surgical aetiology decides resultsSurgical aetiology decides results

Monitoring clinical and laboratory criteriaMonitoring clinical and laboratory criteria

Avoid as far as possible ; difficult weaningAvoid as far as possible ; difficult weaning

Elective ventilation useful armamentElective ventilation useful armament