principles of mechanical ventilation in icu raafat abdel azim
TRANSCRIPT
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Principles ofPrinciples of
Mechanical VentilationMechanical Ventilationin ICUin ICU
Raafat Abdel AzimRaafat Abdel Azim
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TTT of the cause
ETI + MV
PEEP
O2
DrugsIVFV
Secretions
ECMO
ECCO2R
CFAV
Treatment of Respiratory Failure
NPPV
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Oxygen SupplementationOxygen Supplementation
Aim: Aim: PPAAOO2 PaO PaO2 > 60 mmHg (60:100) > 60 mmHg (60:100) If < 60 If < 60 abrupt abrupt of saturation & content of saturation & content If > 100 If > 100 no more benefit no more benefit
Not > 50% > 24hNot > 50% > 24h Potential complication: OPotential complication: O2 PaCOPaCO2
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Methods of OMethods of O22 Supplementation Supplementation
(O(O22 Devices) Devices)
100%
OO22
AIR
(21% OO22)
?% OO22
Flow Rate? Patient’s IFR?
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OO22 Devices Classification Devices Classification
High O2
(up to 100%)Controlled O2
(set)%
Delivered O2 %
Flow Capacity
High Flow Low Flow
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1.1. Nasal CannulaNasal Cannula
Low flow, low O2
OO22 Devices Devices
•Low flow 0.5 – 5 L/min
•Maximal tracheal FIO2 0.4 – 0.5
(cannot be precisely controlled, VE)FR No in FIO2
Drying and irritating effect
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2.2. Air-Entrainment Face Masks Air-Entrainment Face Masks (Venturi Masks)(Venturi Masks)
OO22 Devices Devices
High flow, controlled O2
O2
Air
•High FR
•FIO2 precisely controlled (0.24 – 0.5)
by changing jet nozzle
adjusting FR•Most useful in COPD patients (titratable)
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3.3. Aerosol Face MasksAerosol Face Masks
Moderate flow, variable O2
OO22 Devices Devices
•Large side holes, large bore tubing, a nebulizer
•Flow matching can be evaluated by observing the aerosol mist
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4.4. Reservoir Face MasksReservoir Face Masks
High flow, high O2
OO22 Devices Devices
FR is adjusted so that the reservoir bag remains distended
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5.5. Resuscitation Bag-Mask-Valve UnitResuscitation Bag-Mask-Valve Unit
OO22 Devices Devices
Mask held firmly over the face air entrainment
High flow > 15 L/min
Bag need not be compressed to supply O2
High flow, high O2
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ABGABG PaOPaO22??
SaOSaO22??
PaCOPaCO2 2 > 6 mmHg (in 30 min) = significant > 6 mmHg (in 30 min) = significant
retentionretention
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NPPVNPPV
NPPV ventilator
Nasal mask
Face mask
or or
Standard Ventilator
PS Volume cycled
Patient triggered
•Better tolerated
•Less effective in mouth breathers and edentulous patients
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NPPVNPPV
Not recommended unless the patient is:Not recommended unless the patient is: Alert, oriented & cooperativeAlert, oriented & cooperative Not having:Not having:
Swallowing dysfunctionSwallowing dysfunction Difficulty clearing secretionsDifficulty clearing secretions HypotensionHypotension Uncontrolled arrhythmiasUncontrolled arrhythmias Acute cardiac ischemiaAcute cardiac ischemia Acute GI hemorrhageAcute GI hemorrhage
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May not be desirable with:May not be desirable with: levels of ventilatory requirementslevels of ventilatory requirements
(( C requires C requires P) P) ability to adequately clear secretionsability to adequately clear secretions
(especially with face mask)(especially with face mask) Careful observation and monitoringCareful observation and monitoring Possible G distension & aspiration riskPossible G distension & aspiration risk
NPPVNPPV
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NPPVNPPVSettings
Specialized Unit Standard Ventilator
PS mode
8-12 cmH2O IPAP
AC mode10 ml/kgPEEP or EPAP
Titrate P, V & FIO2 PaO2 & PaCO2
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ETI and MVETI and MVETI when?ETI when?
PaOPaO2 2 < 60 (F< 60 (FIIOO22 >> 0.5) 0.5)
PaCOPaCO2 2 + + pHpH Respiratory muscle fatigueRespiratory muscle fatigue Loss of protective upper airway reflexesLoss of protective upper airway reflexes Ineffective cough + Ineffective cough + secretionssecretions Level of consciousnessLevel of consciousness
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Seconds%I:E
Time
I E
Mode
MVO2 in air
How?
Volume
f
VT
% (FIO2)
PEEPOthers
Alarms & LimitsWave form
FlowTrig. sensitivity 1717
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Mechanism of action of the ventilator (Mode of operation):
4 phases
Inspiratory phase
Expiratory phase
Cycling from I to ECycling from E to I
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Two phases: I & ETwo phase transitions:
From I to E = expiratory cyclingBetween E and I = inspiratory cycling
Inspiration can itself sometimes have two phases: an active ‘flow’ (TI flow) phase during which gas is being delivered to the patientan end-inspiratory pause (TI pause )The total duration of inspiration is made of the sum of these two:
TI = TI flow + TI pause
Respiratory cycle
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2020
Intra-thoracic pressures
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Pressure gradients within the thorax
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Distending pressures
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Control of Parameters of Ventilation
• VT
• f (frequency= rate)
• VM
• I:E ratio
• Flow Rate
• Flow Profile
• Trigger Sensitivity
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IFR (Inspiratory Flow Rate)IFR (Inspiratory Flow Rate)VT (ml)f (b/min)Cycle time
(s)IFRTI (s)TE (s)I:E
L/minL/sml/s
5002060/20 = 360110000.52.51:5
300.5500121:2
Time (sec)
0.500
100
200
300
400
500
600
1.5 2.5 3.5 4.5 5.51 2 3 4 5 6
60 L/min30 L/min
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Inspiratory WaveformsInspiratory Waveforms
30
30
60
60
0
Constant Decelerating Accelerating (ramp)
Sinusoidal (reverse ramp)
TI TI TI TI
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The Ventilation Cycle
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Paw
0 t
PmaxPplat
IF E
ZEEP
IPPV
20
I EP
ause2727
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• Duration of ventilation cycle (sec)
• f (60/duration)
• I phase (IF period, IP period)
• E phase
• VT, VM
• TI, TE, I:E
FVPT2828
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Inspiratory Phase
During the IF period:Paw depends on:
• The airway resistance (R)
• The total thoracic compliance (C) (V/P)
RC2929
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PP PP
P
P
P
PP
PP
P
P
P
Resistance
Flow Rate: FRP3030
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Paw
0 t
20
N R F R F
Resistance
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Calculation of Airway Resistance (Raw) in a Ventilated Patient
Raw = (PIP – Pplat) / Flow
Example: If in a given situation,PIP = 40 cm H2O,Pplat = 38 cm H2O,flow = 60 L/min (i.e., 1 L/s),Raw will be:= (40 − 38)/1= 2 cm H2O/L/s.
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Compliance
C
C
P PVolume
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PVolume: VP
P
Compliance
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During I pause
• No gas F into or out of the lungs Paw depends only on VI & CT
• Gas redistributes among alveoli
• This improves gas distribution in the lungs of patients with small AWD (BA, smokers).
Pause
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Paw
0 t
20
C R
Secretions
Bronchospasm
Kinked ETT
EB intubation
CW rigidity
Pulmonary edema
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Compliance = V/P
Dynamic compliance:
= VT/(PIP-PEEP) L/cmH2O Static compliance:
= VT/(Pplat-PEEP) L/cmH2O
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Time Constants of the LungTime Constants of the LungIn most diseases, the involvement of the lung is not uniform. Regional differences in C and R occur. Owing to this, alveoli in different parts of the lung behave differently; diseased alveoli take longer to fill and to empty.
The rate of filling of an individual lung unit is referred to as its time constant.
For a particular lung unit
Time Constant = R x C3838
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It takes the equivalent of 5 time constants for the lung to completely fill (or to empty).
In the time afforded by one time constant, 63% of the lung will fill (or empty); two time constants allow 86% of the inspiratory or expiratory phase to be completed; three time constants allow for 95%, and four time constants for 98%.
63 86 95 98 10012
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5
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Example:
A lung unit with a normal Raw of 1 cm H2O/L/sand a normal compliance of 0.1 L/cm H2O would have a time constant of:
= 1 × 0.1= 0.1 s
Five times this is 0.5 s, which would be the time required for this unit to fill or empty satisfactorily. This information comes useful while setting a ventilator’s TI and TESince diseased air units take longer to fill, deliberatelyprolonging the TI may enable such units to participatemore meaningfully in gas exchange
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Goals of Mechanical Ventilation
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Provide appropriate O2 supplementation
Assure adequate alveolar VM
work of breathing (WOB)
patient comfort during respiration
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• To provide adequate minute alveolar ventilation
• and to side effects
necessary to maintain the desired PaCO2
PPV ITP
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Adequate Ventilation
• PaCO2 of 40 mmHg = 5.3% of 760 mmHg40/760 = 0.053
• Normal resting VCO2= 200 ml/min= 0.2 L/min• This requires VM of 3.8 L
0.2/ ? = 0.0530.2/ 0.053 =
• Add dead space (VD)
Goals
3.8 L/min
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• N = 2.2 ml/Kg (1 ml/pound) 150 ml in a 70 Kg (154 pound) adult• = 0.15 x 10 (f) =• Required VM = 3.8 + 1.5 =
• A larger VM is required for patients who have VD or VCO2
1.5 L/min
5.3 L
Goals, Adequate Ventilation
For VCO2 For VD
VD phys = VD ana + VD alvVD ana = conducting airways = 150 ml in a 70 Kg adultVD alv is created when non-perfused alveoli are ventilated (negligible in health, expands in disease)This 150 ml of VD ana is reduced by ETT and can be cut down to about 60% by tracheostomy
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• When VCO2 & VD are stable:
VM 1/ PaCO2
VM x PaCO2 = constant
• e.g., PaCO2 = 50 mmHg with VM = 5 L/min
VM to 7 L/min PaCO2 to 36 mmHg
Goals, Adequate Ventilation
V1 x P1aCO2 = V2 x P2aCO2
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VM =VT x f
Manipulation of VT has a different effect on the PaCO2 than does altering f.
Consider the following:A set VT of 500 ml and f of 10 b/min results in a VM of 500 × 10 = 5,000 ml/min. The same VM can be produced by a VT of 250 ml delivered at f of 20 b/min, i.e., 250 × 20 = 5,000 ml/min. If, however, the VD is taken into consideration, the implications of these two settings are vastly different.Assuming a VD phys of 150 ml, the alveolar ventilation (the effective ventilation or the ventilation that takes part in gas exchange) in the first example would be:
(500 – 150) × 10 = 3,500,and in the second example would be:
(250 – 150) × 20 = 2,000.
PaCO2 is inversely proportional not to all of the VM, but to that part of the ventilation that is independent of VD (i.e., the alveolar ventilation VA)
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Side effects
Goals
ITP
VR
EDV
CO
PVR RVAPPV
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Goals, Side Effects
PPV
ITP PA > PAP VVD
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All these effects mean Paw
Therefore, a goal of PPV is to mean Paw while maintaining adequate ventilation and oxygenation
Goals
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Effect of IFR on mean Paw
Mean Paw = area under the curve
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Modes (examples)Modes (examples)
Volume controlled Volume controlled IPPV (CMV)IPPV (CMV)
Pressure controlled Pressure controlled (PCV) (PLV)(PCV) (PLV)
IRVIRV
CPAPCPAP AA ACAC IMVIMV SIMVSIMV PSVPSV BIPAPBIPAP APRVAPRV Other modesOther modes
Breathing support
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Volume Controlled Ventilation Volume Controlled Ventilation (Controlled Mode Ventilation) (CMV) (IPPV)(Controlled Mode Ventilation) (CMV) (IPPV) Initial settings:Initial settings:
ff 10-12 /min10-12 /min VVTT 8-10 ml/Kg 8-10 ml/Kg FFIIOO22 11 I:EI:E 1:2 (1:3 in COPD)1:2 (1:3 in COPD)
AimAim pHpH 7.36 : 7.447.36 : 7.44 PaOPaO22 60: 100 mmHg60: 100 mmHg PaCOPaCO22 36: 44 mmHg36: 44 mmHg
Adjust settings (ABG, SpOAdjust settings (ABG, SpO22 > 92-94%) > 92-94%)5353
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IPPVIPPV Preset f & VPreset f & VTT
No patient interaction with ventilatorNo patient interaction with ventilator Advantage: rests muscles of respirationAdvantage: rests muscles of respiration Disadvantages: requires sedation/NMB, Disadvantages: requires sedation/NMB,
potential adverse hemodynamic effects, potential adverse hemodynamic effects, muscle atrophymuscle atrophy
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Paw
0 t
PmaxPplat
IF E
ZEEP
IPPV
20
I EP
ause5555
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Inspiratory Plateau Pressure (PInspiratory Plateau Pressure (Pplatplat))
PPawaw at end of I with no gas flow present at end of I with no gas flow present
It estimates PIt estimates PA A at end Iat end I Indirect indicator of alveolar distensionIndirect indicator of alveolar distension
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I:E RatioI:E Ratio
Spontaneous breathing I:E = 1:2Spontaneous breathing I:E = 1:2 TTII determinants with preset V breaths: determinants with preset V breaths:
VVTT
GFRGFR ff I pauseI pause
TTEE passively determined passively determined
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I:E RatioI:E Ratio
TTEE too short for exhalation too short for exhalation Breath stackingBreath stacking Auto-PEEPAuto-PEEP
Auto-PEEP by Auto-PEEP by T TII
GFRGFR VVTT
ff
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During the expiratory phaseDuring the expiratory phase
VT
FRC
FRC
EI
FRCIA contents•Pulmonary edema•ARDS
PEEPPaO2 PaO2
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Paw
0 t
PEEP
IPPV + PEEP
6060
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PEEPPEEP
PEEP, When?PEEP, When?PaOPaO22 < 60 mmHg (FIO < 60 mmHg (FIO22 >> 0.5) 0.5)
ActionAction
Expansion of collapsed perfused alveoliExpansion of collapsed perfused alveoli PaOPaO22
CCLL
FRCFRC Prevention of absorption atelectasisPrevention of absorption atelectasis
Improvement of V/Q QS/QT
6161
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PEEP, HowPEEP, How??2.5-5 cmH2.5-5 cmH22O O incrementsincrements until PaO until PaO22 > 60 > 60
(FIO(FIO22 << 0.5) 0.5)
Goal:Goal: PEEP with maximum improvement of PaOPEEP with maximum improvement of PaO2 2
without hazardswithout hazards HazardsHazards
• COP (VR, PVR, left septal displacement)• Barotrauma (Pnx, Pnp, SC emphysema) abrupt PaO2 & COP
PEEPPEEP
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Best PEEP
Best PEEP
O2 transport
Static CL
Don’t give PEEP > 15 cmH2OHow to avoid COP
IVFVInotropicsPA catheter
PEEPPEEP
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Paw
0Sigh phase
Pmax
Int PEEP
PEEP
Intermittent PEEP(Expiratory Sigh)
t
6464
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Auto-PEEPAuto-PEEP Can be measured on some ventilatorsCan be measured on some ventilators peak, plateau, and mean Pawpeak, plateau, and mean Paw Potential harmful physiologic effectsPotential harmful physiologic effects
PEEPPEEP
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Paw
t
Pressure-limited ventilation (PLV) (PCV)
Pmax
Pplat
0
6666
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PCVPCV
Used to limit inflationary pressuresUsed to limit inflationary pressures Allows setting of TAllows setting of TII
Complexity of interacting ventilatory variablesComplexity of interacting ventilatory variables
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Paw
0
20
t I E
Inverse Ratio Ventilation (IRV)
Improves oxygenationNeonatesARDS
Alveolar recruitment by creating auto PEEP
No advantage over 1:1 (+PEEP) at f < 15
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IRVHypoxemic RF
Optimize PEEP
FIO2 requirements > 0.6 or SaO2 < 90%
Consider IRV
VC- IRV PC- IRV
IFR I pause I:E with decelerating flows
Most effective
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Indications of IRVIndications of IRV
ARDS with severe hypoxemic RF (especially ARDS with severe hypoxemic RF (especially with with FIOFIO22 requirements and PEEP) requirements and PEEP)
No uniformly accepted criteria. Proposed No uniformly accepted criteria. Proposed criteria:criteria: VC-IRV:VC-IRV:
FIOFIO22 > 0.6 or PEEP >10 cmH > 0.6 or PEEP >10 cmH22O to maintain SaOO to maintain SaO22
>90%>90% PC-IRV:PC-IRV:
Above parameters + PIP Above parameters + PIP >> 45 cmH 45 cmH22OO7070
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Point of Reference:Spontaneous Breathing (SB)
Breathing Support
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Paw
0 t
SB
-ve
+ve
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Paw
0 t
CPAP
CPAP
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CPAP No machine breaths delivered Allows SB at elevated baseline P
Patient controls f & VT
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Assisted Ventilation (A)Paw
0
A
t
S
Patient f and timingHazard: hypoventilation
If or No S
No A
7575
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Paw
0
A+CProvides a minimum f below which C
Assist-Control (AC)
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AC
Preset VPreset VTT & minimal f & minimal f
Additional patient-initiated breaths receive preset VAdditional patient-initiated breaths receive preset VTT
Advantages: Advantages: WOB; allows pt. to modify V WOB; allows pt. to modify VM
Disadvantages: potential adverse hemodynamic Disadvantages: potential adverse hemodynamic effects or inappropriate hyperventilationeffects or inappropriate hyperventilation
Preferred initial mode in most situations
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IMV
0
Paw
St
Preset VT and f
SB is allowedMuscle atrophy is less likely
IMV PaCOPaCO2 < apneic threshold no SB IMV = IPPV
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Indications of IMVIndications of IMV
Drug overdoseDrug overdose Intermittent heavy sedationIntermittent heavy sedation Unstable ventilatory driveUnstable ventilatory drive Weaning (may be combined with PSV)Weaning (may be combined with PSV)
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Paw
0 tTriggering
window
Mandatory
S
Synch. Mandatory
NO
Preset VT and fSIMV
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SIMV•Preset VT at a preset f
•Additional SBs at VT & f determined by patient
•Often used with PSV
•Indications:•1ry means of MV if adequate VE is delivered
•Severe respiratory alkalosis•To prevent auto PEEP•Weaning
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SIMV
Potential advantagesPotential advantages Better patient-ventilator interactionBetter patient-ventilator interaction Less hemodynamic effectsLess hemodynamic effects
Potential disadvantages Potential disadvantages Higher WOB > CMV, ACHigher WOB > CMV, AC
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Pressure Support Ventilation (PSV)(Inspiratory Pressure Support = IPS)
(Assisted Spontaneous Breathing = ASB)
0
Paw
Spont.
PSV
Trig. Sensitivity
t
8383
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Paw
0
CPAP
t
PSV
8484
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PSV Pressure assist during SB (= ASB)Pressure assist during SB (= ASB) P assist continues until inspiratory effort P assist continues until inspiratory effort Delivered Delivered VVTT dependent on I effort & R/C of dependent on I effort & R/C of
lung/thoraxlung/thorax
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PSV
Potential advantagesPotential advantages Patient comfort Patient comfort WOB < SBWOB < SB May enhance patient-ventilator synchronyMay enhance patient-ventilator synchrony Used with SIMV to support SBUsed with SIMV to support SB
Indications:Indications: Stable patients receiving long-term MV (Stable patients receiving long-term MV (WOB)WOB) WeaningWeaning
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PSV
Potential disadvantages
–Variable VT if pulmonary R/C changes rapidly
–If sole mode of ventilation, apnea alarm is only backup
–Gas leak from circuit may interfere with cycling
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Paw
0 t
CPAP
Apnea alarm
15 s
IPPV
Apnea time
15-60 s
Apnea Ventilation
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Paw
0 t
Biphasic Intermittent Positive Airway Pressure
BIPAP (PCV+)
Spont.
Spont.
PCV
P1
P2
T high T low
P & T can be independently set
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SB superimposed on standard PCV
9090
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PCV: closed
BIPAP: controlled
E valve
9191
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Auto Flow
Auto flow Auto flow application of the "open application of the "open breathing system" even to Volume Controlled breathing system" even to Volume Controlled ventilation modesventilation modes
Can be used + any Volume oriented mode like Can be used + any Volume oriented mode like IPPVIPPV SIMVSIMV MMVMMV
BIPAP
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CPAP
SIMV-BIPAP
IPPV-BIPAP
Genuine BIPAP
No SB
SB only at P level
Continuous SB at 2 P levels
Continuous SB, both P levels are equal
Mode Contribution of SB
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SB possible at all times (open breathing system) Patient comfort
Patient is never locked out No fighting against the ventilator Can cough and clear his airways at any time
Sedation/MR required Improved SB Proph. & ttt of atelectasis No barotrauma or CVS Full ventilatory support, No switching between Full ventilatory support, No switching between
modes is requiredmodes is required
BIPAP
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Airway Pressure Release Ventilation (APRV)
P high PAO2
P low CO2
SB on 2 CPAP levels
E
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MV is achieved by MV is achieved by instead of instead of Paw Paw If no SB, APRV = PC-IRVIf no SB, APRV = PC-IRV Barotrauma (Barotrauma ( Pp Pp –– Pmean) Pmean) CVSCVS Indications: (not clear)Indications: (not clear)
Mild ALIMild ALI Alveolar hypoventilation states with minimal Alveolar hypoventilation states with minimal
airflow obstructionairflow obstruction
APRV
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Bilevel Positive Airway Pressure (BiPAP) System
A home care device PSV to augment patient ventilation
A non-invasive alternative to traditional management in non life support applications
2 levels of PP
PCycling between the 2 levels is in response to patient F
If the patient fails to initiate P change a timed phase9797
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Useful in (home care):Useful in (home care): Obstructive sleep apneaObstructive sleep apnea COPDCOPD Musculoskeletal disordersMusculoskeletal disorders
BiPAP
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BIPAP = PCV + SB at all timesBIPAP = PCV + SB at all times APRV = similar + extended times at higher PsAPRV = similar + extended times at higher Ps BiPAP system = a non continuous form of BiPAP system = a non continuous form of
breathing support breathing support
9999
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Advantages of different modesCMVCMVRests muscles of respirationRests muscles of respiration
ACACPatient determines amount of ventilatory supportPatient determines amount of ventilatory supportWOBWOB
SIMVSIMVImproved patient-ventilator interactionImproved patient-ventilator interactionInterference with normal CV functionInterference with normal CV function
PSVPSVPatient comfortPatient comfortImproved patient-ventilator interactionImproved patient-ventilator interactionWOBWOB
PCVPCVAllows limitation of PIPAllows limitation of PIPControl of I:EControl of I:E
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Disadvantages of different modesCMVCMVNo patient-ventilator interactionNo patient-ventilator interaction
Requires sedation/NMBRequires sedation/NMBMuscle atrophyMuscle atrophyPotential adverse hemodynamic effectsPotential adverse hemodynamic effects
ACACPotential adverse hemodynamic effectsPotential adverse hemodynamic effectsMay lead to inappropriate hyperventilationMay lead to inappropriate hyperventilation
SIMVSIMVWOB compared to ACWOB compared to AC
PSVPSVApnea alarm is only backupApnea alarm is only backupVariable effect on patient toleranceVariable effect on patient tolerance
PCVPCVPotential hyper- or hypoventilation with R/C Potential hyper- or hypoventilation with R/C changeschanges
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High Frequency Ventilation (HFV) What is it? What is it? VVT T (1-3 ml/kg)(1-3 ml/kg) , , ff Types:Types:
Applied to chest wall:Applied to chest wall:
HF body surface oscillationsHF body surface oscillations Applied at air openings:Applied at air openings:
HFPPVHFPPV 60-110 b/min60-110 b/min (60-100)(60-100) HFJVHFJV 110-400 b/min110-400 b/min (100-600)(100-600) HFOHFO 400-2400 b/min400-2400 b/min (300-3000)(300-3000)
102102
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AdvantagesAdvantages:: Raw and CRaw and CLL don don’’t affect efficacy of t affect efficacy of
ventilationventilation Paw Paw no no COP, no barotrauma COP, no barotrauma Reflex suppression of SB Reflex suppression of SB no need for no need for
sedatives/MRsedatives/MR
HFV
103103
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IndicationsIndications BP fistulaBP fistula Bronchoscopy, upper AW proceduresBronchoscopy, upper AW procedures ARDSARDS Patients at Patients at risk for barotrauma (stiff L + risk for barotrauma (stiff L + Paw)Paw) Patients who cannot be intubatedPatients who cannot be intubated ICPICP ShockShock Thoracic surgery (e.g., descending A. Aneurysm)Thoracic surgery (e.g., descending A. Aneurysm) LithotripsyLithotripsy
HFV
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Permissive Hypercapnia
Acceptance of Acceptance of Pa PaCOCO22, e.g., , e.g., V VTT to to peak peak
PawPaw
Contraindicated with Contraindicated with ICP ICP
Consider in severe asthma and ARDS Consider in severe asthma and ARDS
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Pediatric Considerations
Infants (< 5 kg)
–Time-cycled, PLV
–PIP initiated at 18–20 cm H2O
–Adjust to adequate chest movement or exhaled VT 10–15 mL/kg
–Low level of PEEP (2–4 cm H2O) to prevent alveolar collapse
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ChildrenChildren SIMV modeSIMV mode VVTT 10 mL/kg 10 mL/kg
Flow rate adjusted to yield desired TFlow rate adjusted to yield desired TII
Infants 0.6Infants 0.6––0.7 secs0.7 secs Toddlers 0.8 secsToddlers 0.8 secs Older 0.9Older 0.9––1.0 secs1.0 secs
f <18-20 /minf <18-20 /min PEEP 2-4 cm HPEEP 2-4 cm H22OO 107107
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108108