MechanicalVentilator-ARDS

MechanicalVentilatorARDS

Description

A male patient with a predicted body weight of 60 kg is mechanically ventilated with varying severities of ARDS. These are the data sources:

  • Resistance: Rinsp is assumed equal to Rexp, taken from Arnal et al [1] (Table 3).
  • Compliance: All compliances were taken from Maj et al [8] (Table 1) derived as tidal volume (ie, mL/kg x PBW calcualted with ARDS equation for males) divided by driving pressure. Mild ARDS was mean minus 1 standard deviatio; moderate ARDS was the mean value; severe ARDS was mean plus 1 standard deviation.
  • Dead space: VD/VT values were taken from Maj et al [8] (Table 2).
  • Shunt: Values for QS/QT were a compromise between Maj et al [8] (Table 2, venous admixture) and Torres et al [13] (Table 3) to give realistic PO2 results for the simulated ventilator settings.
  • Ventilator Settings: All ventilator settings were takeng from Arnal et al [1] (Table 2) for a male patient aged 73 years and predicted body weight of 60 kg. Note that the mode for simulation is PC-CMV, which is equivalent to the mode used by Arnal et [1] for passive pateints. Equivalent settings for tidal volume, rate, and inspiratory time can be used for volume control simulations.
  • Blood Gas Values: Expected blood gas value for outputs of Pulse simulator were taken from the most complete source: Arnal et al [1] (Table 2). FiO2 values for moderate and severe ARDS were adjusted upward to give the expected P/F ratios for the given PaO2 ranges. Expected values for SpO2 were calculated from PaO2 using the equation from Gadrey et al [4].

Segment Validation

Segment 1

Diagnosis: Mild ARDS (severity = 0.3).
Ventilator settings are (VT Target = 6.9 mL/kg (ideal)):

Mode VT (mL) PIP (cmH2O) Flow (L/min) I:E TI (s) RR (bpm) PEEP (cmH2O) FiO2
PC-CMV 414 Adjust NA 0.83 1.3 21 10 0.31
Table 1. Data request validation results for Segment 1.
Property Name Validation Engine Value Percent Error Percent Change Notes
InspiratoryRespiratoryResistance(cmH2O_s/L) EqualTo (12.0) [1] 11.6 3.17%   Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L) EqualTo (12.0) [1] 11.6 3.18%   Rexp
RespiratoryCompliance(mL/cmH2O) EqualTo (40.0) [8] 40.9 2.20%   C
ApparentPhysiologicDeadSpaceTidalVolumeRatio EqualTo (0.540) [8] 0.545 0.925%   VD/VT (determined from blood gas values)
ApparentShuntFraction EqualTo (0.200) [8] [13] 0.151 27.9%   QS/QT (determined from blood gas values)
MechanicalVentilator-TidalVolume(mL) EqualTo (414) [1] 422 1.82%   VT (measured)
BloodPH [7.28,7.40] [1] 7.37 0.00%   pH
Aorta-Oxygen-PartialPressure(mmHg) [72.0,88.0] [1] 107 19.8%   PaO2
Aorta-CarbonDioxide-PartialPressure(mmHg) [37.0,46.0] [1] 44.4 0.00%   PaCO2
OxygenSaturation [0.940,0.970] [4] 0.982 1.24%   SpO2
HorowitzIndex(mmHg) [232,284] [1] 347 20.0%   PaO2/FiO2
HorowitzIndex(mmHg) [200,300] [3] 347 14.5%   PaO2/FiO2


Figure 1. Vitals and ventilator monitors for Segment 1.


Table 2. Data requests for Segment 1.
Property Name Engine Value
Patient-Height(in) 64.3
Patient-IdealBodyWeight(kg) 60.0
InspiratoryRespiratoryResistance(cmH2O_s/L) 11.6
ExpiratoryRespiratoryResistance(cmH2O_s/L) 11.6
RespiratoryCompliance(mL/cmH2O) 40.9
ApparentPhysiologicDeadSpaceTidalVolumeRatio 0.545
ApparentShuntFraction 0.151
MechanicalVentilator-TidalVolume(L) 0.422
BloodPH 7.37
Aorta-Oxygen-PartialPressure(mmHg) 107
Aorta-CarbonDioxide-PartialPressure(mmHg) 44.4
Aorta-Bicarbonate-Molarity(mEq/L) 26.1
OxygenSaturation 0.982
HorowitzIndex(mmHg) 347
IntrinsicPositiveEndExpiratoryPressure(cmH2O) 0.385
MechanicalVentilator-RespirationRate(1/min) 21.0
MechanicalVentilator-MeanAirwayPressure(cmH2O) 15.1
MechanicalVentilator-PeakInspiratoryPressure(cmH2O) 21.5
MechanicalVentilator-PlateauPressure(cmH2O) 20.8
HeartRate(1/min) 69.9
SystolicArterialPressure(mmHg) 115
DiastolicArterialPressure(mmHg) 72.9
MechanicalVentilator-TotalPulmonaryVentilation(L/min) 8.84
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L) 11.6
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L) 11.6
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O) 40.5
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O) 36.7
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg) 34.4
MechanicalVentilator-EndTidalOxygenPressure(mmHg) 196
MechanicalVentilator-ExpiratoryTidalVolume(L) 0.422
MechanicalVentilator-InspiratoryExpiratoryRatio 0.833
MechanicalVentilator-InspiratoryTidalVolume(L) 0.422
MechanicalVentilator-PeakExpiratoryFlow(L/s) 0.750
MechanicalVentilator-LeakFraction 7.27e-14
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O) 0.379
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O) 10.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O) 10.4
PhysiologicDeadSpaceTidalVolumeRatio 0.516
ShuntFraction 0.0902
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L) 11.6
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L) 11.6
TotalRespiratoryModelCompliance(mL/cmH2O) 47.6
ExtrinsicPositiveEndExpiratoryPressure(cmH2O) 10.0
TotalPositiveEndExpiratoryPressure(cmH2O) 10.4
EndTidalCarbonDioxidePressure(mmHg) 37.7
PhysiologicDeadSpace(mL) 217
AlveolarArterialGradient(mmHg) 81.0
AlveolarDeadSpace(mL) 96.6
AnatomicDeadSpace(mL) 120
ChestWallCompliance(L/cmH2O) 0.142
FractionOfInspiredOxygen 0.309
LungCompliance(L/cmH2O) 0.0585
VentilationPerfusionRatio 1.73
HeartStrokeVolume(mL) 80.5
HeartEjectionFraction 0.578
BloodVolume(L) 4.15
MeanArterialPressure(mmHg) 95.4
PulsePressure(mmHg) 42.2
CardiacOutput(L/min) 5.62
CarbonDioxideSaturation 0.134
RespiratoryExchangeRatio 0.827
SystemicVascularResistance(mmHg_s/mL) 0.969
OxygenConsumptionRate(mL/min) 195
CarbonDioxideProductionRate(mL/min) 162
Patient-AlveoliSurfaceArea(m^2) 27.2
Patient-ExpiratoryReserveVolume(L) 0.687
Patient-FunctionalResidualCapacity(L) 1.28
Patient-InspiratoryCapacity(L) 2.45
Patient-InspiratoryReserveVolume(L) 2.02
Patient-ResidualVolume(L) 0.594
Patient-TidalVolumeBaseline(L) 0.435
Patient-TotalLungCapacity(L) 3.73
Patient-VitalCapacity(L) 3.14

Segment 2

Diagnosis: Moderate ARDS (severity = 0.6).
Ventilator settings are (VT Target = 6.6 mL/kg (ideal)):

Mode VT (mL) PIP (cmH2O) Flow (L/min) I:E TI (s) RR (bpm) PEEP (cmH2O) FiO2
PC-CMV 396 Adjust NA 0.91 1.2 23 12 0.50
Table 3. Data request validation results for Segment 2.
Property Name Validation Engine Value Percent Error Percent Change Notes
InspiratoryRespiratoryResistance(cmH2O_s/L) EqualTo (12.0) [1] 12.4 3.08%   Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L) EqualTo (12.0) [1] 12.4 3.09%   Rexp
RespiratoryCompliance(mL/cmH2O) EqualTo (35.0) [8] 35.6 1.79%   C
ApparentPhysiologicDeadSpaceTidalVolumeRatio EqualTo (0.570) [8] 0.578 1.40%   VD/VT (determined from blood gas values)
ApparentShuntFraction EqualTo (0.300) [8] [13] 0.307 2.31%   QS/QT (determined from blood gas values)
MechanicalVentilator-TidalVolume(mL) EqualTo (396) [1] 405 2.19%   VT (measured)
BloodPH [7.26,7.41] [1] 7.36 0.00%   pH
Aorta-Oxygen-PartialPressure(mmHg) [70.0,94.0] [1] 83.6 0.00%   PaO2
Aorta-CarbonDioxide-PartialPressure(mmHg) [39.0,50.0] [1] 45.4 0.00%   PaCO2
OxygenSaturation [0.940,0.970] [4] 0.965 0.00%   SpO2
HorowitzIndex(mmHg) [140,188] [1] 167 0.00%   PaO2/FiO2
HorowitzIndex(mmHg) [100,200] [3] 167 0.00%   PaO2/FiO2


Figure 2. Vitals and ventilator monitors for Segment 2.


Table 4. Data requests for Segment 2.
Property Name Engine Value
Patient-Height(in) 64.3
Patient-IdealBodyWeight(kg) 60.0
InspiratoryRespiratoryResistance(cmH2O_s/L) 12.4
ExpiratoryRespiratoryResistance(cmH2O_s/L) 12.4
RespiratoryCompliance(mL/cmH2O) 35.6
ApparentPhysiologicDeadSpaceTidalVolumeRatio 0.578
ApparentShuntFraction 0.307
MechanicalVentilator-TidalVolume(L) 0.405
BloodPH 7.36
Aorta-Oxygen-PartialPressure(mmHg) 83.6
Aorta-CarbonDioxide-PartialPressure(mmHg) 45.4
Aorta-Bicarbonate-Molarity(mEq/L) 26.2
OxygenSaturation 0.965
HorowitzIndex(mmHg) 167
IntrinsicPositiveEndExpiratoryPressure(cmH2O) 0.465
MechanicalVentilator-RespirationRate(1/min) 22.9
MechanicalVentilator-MeanAirwayPressure(cmH2O) 17.7
MechanicalVentilator-PeakInspiratoryPressure(cmH2O) 24.7
MechanicalVentilator-PlateauPressure(cmH2O) 23.9
HeartRate(1/min) 67.4
SystolicArterialPressure(mmHg) 116
DiastolicArterialPressure(mmHg) 72.2
MechanicalVentilator-TotalPulmonaryVentilation(L/min) 9.27
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L) 12.4
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L) 12.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O) 35.5
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O) 31.9
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg) 32.3
MechanicalVentilator-EndTidalOxygenPressure(mmHg) 347
MechanicalVentilator-ExpiratoryTidalVolume(L) 0.405
MechanicalVentilator-InspiratoryExpiratoryRatio 0.845
MechanicalVentilator-InspiratoryTidalVolume(L) 0.405
MechanicalVentilator-PeakExpiratoryFlow(L/s) 0.768
MechanicalVentilator-LeakFraction 1.25e-13
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O) 0.450
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O) 12.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O) 12.4
PhysiologicDeadSpaceTidalVolumeRatio 0.554
ShuntFraction 0.263
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L) 12.4
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L) 12.4
TotalRespiratoryModelCompliance(mL/cmH2O) 39.5
ExtrinsicPositiveEndExpiratoryPressure(cmH2O) 12.0
TotalPositiveEndExpiratoryPressure(cmH2O) 12.5
EndTidalCarbonDioxidePressure(mmHg) 35.8
PhysiologicDeadSpace(mL) 233
AlveolarArterialGradient(mmHg) 250
AlveolarDeadSpace(mL) 113
AnatomicDeadSpace(mL) 120
ChestWallCompliance(L/cmH2O) 0.134
FractionOfInspiredOxygen 0.499
LungCompliance(L/cmH2O) 0.0495
VentilationPerfusionRatio 2.22
HeartStrokeVolume(mL) 83.7
HeartEjectionFraction 0.588
BloodVolume(L) 4.18
MeanArterialPressure(mmHg) 95.4
PulsePressure(mmHg) 43.5
CardiacOutput(L/min) 5.64
CarbonDioxideSaturation 0.182
RespiratoryExchangeRatio 0.831
SystemicVascularResistance(mmHg_s/mL) 0.965
OxygenConsumptionRate(mL/min) 198
CarbonDioxideProductionRate(mL/min) 164
Patient-AlveoliSurfaceArea(m^2) 10.9
Patient-ExpiratoryReserveVolume(L) 0.671
Patient-FunctionalResidualCapacity(L) 0.976
Patient-InspiratoryCapacity(L) 2.40
Patient-InspiratoryReserveVolume(L) 1.96
Patient-ResidualVolume(L) 0.305
Patient-TidalVolumeBaseline(L) 0.435
Patient-TotalLungCapacity(L) 3.37
Patient-VitalCapacity(L) 3.07

Segment 3

Diagnosis: Severe ARDS (severity = 0.9).
Ventilator settings are (VT Target = 6.6 mL/kg (ideal)):

Mode VT (mL) PIP (cmH2O) Flow (L/min) I:E TI (s) RR (bpm) PEEP (cmH2O) FiO2
PC-CMV 396 Adjust NA 1.0 1.2 25 12 0.80
Table 5. Data request validation results for Segment 3.
Property Name Validation Engine Value Percent Error Percent Change Notes
InspiratoryRespiratoryResistance(cmH2O_s/L) EqualTo (12.0) [1] 13.1 8.95%   Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L) EqualTo (12.0) [1] 13.1 8.97%   Rexp
RespiratoryCompliance(mL/cmH2O) EqualTo (33.0) [8] 33.1 0.256%   C
ApparentPhysiologicDeadSpaceTidalVolumeRatio EqualTo (0.650) [8] 0.708 8.50%   VD/VT (determined from blood gas values)
ApparentShuntFraction EqualTo (0.400) [8] [13] 0.454 12.7%   QS/QT (determined from blood gas values)
MechanicalVentilator-TidalVolume(mL) EqualTo (396) [1] 402 1.47%   VT (measured)
BloodPH [7.21,7.34] [1] 7.24 0.00%   pH
Aorta-Oxygen-PartialPressure(mmHg) [68.0,80.0] [1] 79.2 0.00%   PaO2
Aorta-CarbonDioxide-PartialPressure(mmHg) [44.0,56.0] [1] 61.9 9.95%   PaCO2
OxygenSaturation [0.920,0.950] [4] 0.944 0.00%   SpO2
HorowitzIndex(mmHg) [85.0,100] [1] 99.1 0.00%   PaO2/FiO2
HorowitzIndex(mmHg) LessThan (100) [3] 99.1   -0.915% PaO2/FiO2


Figure 3. Vitals and ventilator monitors for Segment 3.


Table 6. Data requests for Segment 3.
Property Name Engine Value
Patient-Height(in) 64.3
Patient-IdealBodyWeight(kg) 60.0
InspiratoryRespiratoryResistance(cmH2O_s/L) 13.1
ExpiratoryRespiratoryResistance(cmH2O_s/L) 13.1
RespiratoryCompliance(mL/cmH2O) 33.1
ApparentPhysiologicDeadSpaceTidalVolumeRatio 0.708
ApparentShuntFraction 0.454
MechanicalVentilator-TidalVolume(L) 0.402
BloodPH 7.24
Aorta-Oxygen-PartialPressure(mmHg) 79.2
Aorta-CarbonDioxide-PartialPressure(mmHg) 61.9
Aorta-Bicarbonate-Molarity(mEq/L) 26.9
OxygenSaturation 0.944
HorowitzIndex(mmHg) 99.1
IntrinsicPositiveEndExpiratoryPressure(cmH2O) 0.792
MechanicalVentilator-RespirationRate(1/min) 25.0
MechanicalVentilator-MeanAirwayPressure(cmH2O) 18.9
MechanicalVentilator-PeakInspiratoryPressure(cmH2O) 26.0
MechanicalVentilator-PlateauPressure(cmH2O) 25.0
HeartRate(1/min) 70.2
SystolicArterialPressure(mmHg) 117
DiastolicArterialPressure(mmHg) 72.2
MechanicalVentilator-TotalPulmonaryVentilation(L/min) 10.0
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L) 13.1
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L) 13.1
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O) 32.7
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O) 28.7
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg) 32.5
MechanicalVentilator-EndTidalOxygenPressure(mmHg) 581
MechanicalVentilator-ExpiratoryTidalVolume(L) 0.402
MechanicalVentilator-InspiratoryExpiratoryRatio 1.00
MechanicalVentilator-InspiratoryTidalVolume(L) 0.402
MechanicalVentilator-PeakExpiratoryFlow(L/s) 0.803
MechanicalVentilator-LeakFraction 0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O) 0.750
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O) 12.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O) 12.8
PhysiologicDeadSpaceTidalVolumeRatio 0.630
ShuntFraction 0.401
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L) 13.1
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L) 13.1
TotalRespiratoryModelCompliance(mL/cmH2O) 36.7
ExtrinsicPositiveEndExpiratoryPressure(cmH2O) 12.0
TotalPositiveEndExpiratoryPressure(cmH2O) 12.8
EndTidalCarbonDioxidePressure(mmHg) 36.3
PhysiologicDeadSpace(mL) 264
AlveolarArterialGradient(mmHg) 491
AlveolarDeadSpace(mL) 144
AnatomicDeadSpace(mL) 120
ChestWallCompliance(L/cmH2O) 0.132
FractionOfInspiredOxygen 0.799
LungCompliance(L/cmH2O) 0.0450
VentilationPerfusionRatio 2.72
HeartStrokeVolume(mL) 88.3
HeartEjectionFraction 0.596
BloodVolume(L) 4.34
MeanArterialPressure(mmHg) 96.0
PulsePressure(mmHg) 45.1
CardiacOutput(L/min) 6.20
CarbonDioxideSaturation 0.193
RespiratoryExchangeRatio 0.831
SystemicVascularResistance(mmHg_s/mL) 0.881
OxygenConsumptionRate(mL/min) 197
CarbonDioxideProductionRate(mL/min) 163
Patient-AlveoliSurfaceArea(m^2) 5.45
Patient-ExpiratoryReserveVolume(L) 0.663
Patient-FunctionalResidualCapacity(L) 0.703
Patient-InspiratoryCapacity(L) 2.37
Patient-InspiratoryReserveVolume(L) 1.93
Patient-ResidualVolume(L) 0.0404
Patient-TidalVolumeBaseline(L) 0.435
Patient-TotalLungCapacity(L) 3.07
Patient-VitalCapacity(L) 3.03

Scenario Output Plots


Figure 4. Select outputs from the scenario.