mechanical ventilation (2)
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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
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