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Transcript of Ventilator Graphics Vijay Deshpande, MS, RRT, FAARC Emeritus Professor Georgia State University...
Ventilator Graphics
Vijay Deshpande, MS, RRT, FAARC
Emeritus ProfessorGeorgia State UniversityAtlanta, Georgia, USA
Adjunct Visiting Professor,Manipal UniversityCollege of Allied Health SciencesManipal, Karnataka, INDIA
Mechanical Ventilation
GraphicsSCALARS LOOPS
Inspiratory Flow Pattern Inspiratory Flow Pattern
Inspiration
Expiration
Time (sec)
Flo
w (
L/m
in)
Beginning of inspirationexhalation valve closes
Peak inspiratory flow ratePIFR
Beginning of expirationexhalation valve opens
Total cycle timeTCT
Insp. timeTI
Expiratory Time TE
Expiratory Flow PatternExpiratory Flow Pattern
Inspiration
Expiration
Time (sec)
Flo
w (
L/m
in)
Beginning of expirationexhalation valve opens
Peak Expiratory Flow RatePEFR
Duration of expiratory flow
Expiratory time
TE
Auto-PEEPAuto-PEEP
Inspiration
Expiration
NormalPatient
Time (sec)
Flo
w (
L/m
in)
Air TrappingAuto-PEEP
}
Inadequate Inspiratory FlowInadequate Inspiratory Flow
Flow (L/min)
Time (sec)
NormalAbnormal
Active Inspiration or Asynchrony
Patient’s effort
Inspiration
Expiration
Time (sec)
Vo
lum
e (m
l)
Inspiratory Tidal Volume
TI
Volume Ventilation breaths are Volume Cycled
Volume Cycling
Air LeakAir LeakV
olu
me
(ml)
Time (sec)
Air Leak
Components of Inflation PressureComponents of
Inflation Pressure
Begin Expiration
P aw (
cm H
2O)
Time (sec)
Begin Inspiration
PIP
Pplateau
(Palveolar)
Transairway Pressure (PTA)}Exhalation Valve Opens
Expiration
Inspiratory Pause
Inadequate Inspiratory Flow
Adequate Flow
Time (sec)
Inadequate Flow
Pa
w
(cm
H2O
)
Assisted Mode(Volume-Targeted Ventilation)
Assisted Mode(Volume-Targeted Ventilation)
Time (sec)
FlowL/m
Pressurecm H2O
VolumemL
Preset VTVolume Cycling
Patient triggered, Flow limited, Volume cycled Ventilation
From: Essentials of Ventilator Graphics- An interactive CD. Vijay Deshpande, MS, RRT and Ruben Restrepo, MD, RRT. Available at www.respiratorybooks.com
SIMV(Volume-Targeted Ventilation)
SIMV(Volume-Targeted Ventilation)
Spontaneous Breaths
FlowL/m
Pressurecm H2O
VolumemL
Pressure
Flow
Volume
(L/min)
(cm H2O)
(ml)
SIMV + PS (Pressure-Targeted Ventilation)
SIMV + PS (Pressure-Targeted Ventilation)
PS Breath
Set PS levelSet PC level
Time (sec)
Time-Cycled Flow-Cycled
Fig 7.21
PSVPSV
Time (sec)
Flow CyclingFlow Cycling
Set PS level
Set PS level
FlowL/m
Pressurecm H2O
VolumemL
PSV Flow-Cycle CriteriaF
low
T
Peak Inspiratory Flow
5%20%
40%
CPAP + PSV ( BiPAP ) CPAP + PSV ( BiPAP )
Set PS level
CPAP level
Time (sec)
FlowL/m
Pressurecm H2O
VolumemL
Flow Cycling
Fig 7.31
Components of Pressure-Volume LoopComponents of Pressure-Volume Loop
Volume (mL)
Insp
irat
ion
Expirat
ion
PIP
VT
Paw (cm H2O)
Air LeakAir Leak
Volume (ml)
Pressure (cm H2O)
Air Leak
Inadequate Inspiratory FlowInadequate Inspiratory Flow
Paw (cm H2O)
Volume (ml)
NormalAbnormal
Active Inspiration
Inappropriate Flow
Increased RawIncreased Raw
Pressure (cm H2O)
Higher PTA
Norm
al S
lope
Vol (mL)
Lower S
lope
Lung Compliance Changes and the P-V LoopLung Compliance Changes and the P-V Loop
Volume (mL)
PIP levels
Preset VT
Paw (cm H2O)
COMPLIANCEIncreasedNormalDecreased
COMPLIANCEIncreasedNormalDecreased
Volume Targeted Ventilation
Over-distentionOver-distention
Volu
me (
ml)
Pressure (cm H2O)
With little or no change in VT
With little or no change in VT
Paw rises
Paw rises
NormalAbnormal
Preset Tidal Volume
Lung Compliance Changes and the P-V Loop
Lung Compliance Changes and the P-V Loop
Volume (mL)
PIP levels
Preset VT
Paw (cm H2O)
COMPLIANCEIncreasedNormalDecreased
COMPLIANCEIncreasedNormalDecreased
Volume Targeted Ventilation
Flow-Volume LoopFlow-Volume Loop
Volume (ml)
PEFR
FRC
Inspiration
Expiration
Flo
w (
L/m
in) PIFR
VT
Air LeakAir Leak
Inspiration
Expiration
Volume (ml)
Flow (L/min)
Air Leak in mL
NormalAbnormal
Air TrappingAir TrappingInspiration
Expiration
Volume (ml)
Flow (L/min)
Does not returnto baseline
NormalAbnormal
Assisted Mode (Pressure-Targeted Ventilation)Assisted Mode (Pressure-Targeted Ventilation)
Pressure
Flow
Volume
(L/min)
(cm H2O)
(ml)
Set PC level
Time (sec)
Time-Cycled
Patient Triggered, Pressure Limited, Time Cycled Ventilation
Assisted Mode(Volume-Targeted Ventilation)
Assisted Mode(Volume-Targeted Ventilation)
Time (sec)Time (sec)
FlowL/m
Pressurecm H2O
VolumemL
Preset VT
Volume Cycling
Patient triggered, Flow limited, Volume cycled Ventilation
Assisted Mode (Pressure-Targeted Ventilation)
Assisted Mode (Pressure-Targeted Ventilation)
Pressure
Flow
Volume
(L/min)
(cm H2O)
(ml)
Set PC level
Time (sec)Time (sec)
Time-Cycled
Patient Triggered, Pressure Limited, Time Cycled Ventilation
Scalars in Assisted Mode
FIGURE 1
Pressure Control VentilationFlow – Time Scalar
Flow
Time
TIMECYCLING
TI
Fig 8.16
PCV with long T I or Decreased Lung Compliance
Exhalation ValveOpens
Inspiratory flowDecreases to zero
No FlowPeriod
Flow
Time Set TI
Fig 8.17
Flow
Time
TI
Pressure Control Ventilation with inadequate TI
TIME CYCLINGExhalation valve opens
Fig 8.18
Pressure Control Ventilation - Effect of Changes in Lung Compliance on Flow-time scalar
Flow
TIMECYCLING
A
B
C
TI
A : Decreased ComplianceB : Normal complianceC : Increased Compliance
Fig 8.19
Thank You !
Apnea Alarm
Patient becomes Apneic Disconnection inSedated Patient
Oversedation inPatients on Low rate SIMV or PCV
“Ventilator inoperative”
Alarm
Absent Electrical Source(Unplugged)
Power Failure
Internal Batteryhas very low charge
High Minute Volume or High
Respiratory Frequency
Pain Anxiety
Hypoxemia
Low PEEP Alarm
Active Inspiration Inappropriate Alarm setting
A leak in the circuit
Other Useful Alarms
● High Minute Volume
Check Sensitivity setting for trigger level If using external nebulizer, reset the alarm until the treatment is completed, and then reset it to the initial setting. Check physiological causes of increased minute ventilation
● Low FiO2
Check Gas Source pressures Check Oxygen sensor for proper function (using oxygen analyzer)
High Pressure Alarm
Asynchrony(patient fighting)
Increased Resistance
Decreased Lung Compliance
Coughing
Secretions Bronchospasm
Kinking or displacement of
the tube
Pneumothorax Pulmonary
Edema, Pleural
Effusion
Inadequate Flow
Auto PEEP, Improper
Sensitivity
Low Pressure Alarm
Leak In the System,Tracheal Tube Cuff Leak, Chest tube leakage
Proximal PressureLine Disconnected
PatientDisconnection
Associated withlow minute ventilationor low tidal volume
Low Tidal volume or
Low Minute Volume
Leak In the System
Partial Disconnection
Increase in f or decreasein Tidal Volume( In Volume Ventilation)
Increased Resistanceand/or Decreased Lungcompliance
(Leak in the system does NOTTrigger low volume alarm)
IN VOLUME VENTILATION IN PRESSURE VENTILATION
42
Double triggering
Volume-targeted ventilation. Notice the circled double volume breath and the pressure-time Waveform to drop below baseline triggering another breath immediately following the first breath. Hallmark of double triggering-peak pressure of the second breath rises as the second breath is stacked on the first breath.
From Nilsestuen J, Hargett K. Using Ventilator Graphics to Identify Patient-Ventilator Asynchrony. Resp Care 2005;50(2):202-234
43
Double triggering
44
Causes Commonly occurs with VC continuous mandatory
ventilation Also with PSV with high termination flow criterion High respiratory drive Insufficient respiratory support such as minute ventilation
or tidal volume too low with a high respiratory rate. Patient’s Itime (neural) is different (longer) than the
ventilator set Itime Small Vt and short inspiratory time
Missed trigger with pressure control ventilation using the expiratory flow waveform.
The arrow points to the positive flow deflection that is the hallmark sign of a missed trigger.
Missed triggers
45From: Branson R, Blakeman T, Robinson B. Respiratory Care, 2013
Ineffective inspiratory efforts corrected by flow and expiratory time
COPD receiving assist-control ventilation with a constant Vt of 0.55 L. Arrows indicate ineffective ventilation with flow rate at 30 L/min in A.
Black arrows indicate ineffective inspiratory efforts.
Inspiratory flow rate was increased to 90 L/min which decreased inspiratory time and prolonged expiratory time.
This reduced dynamic hyperinflation and the number of ineffective ventilations was reduced.
Increasing flow rate can help reduce ineffective triggeringin COPD patients with dynamic hyperinflation.
During pressure control ventilation reducing inspiratory time will prolong expiratory time to help reduce dynamichyperinflation.
From:Kondili E, Prinianakis G, Georgopoulos D. Patient-Ventilator interaction. Br J Anaesth 2003;91(1):106-119 46
Inspiratory Rise Time
Inspiratory Time