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 [18] (Table 3).
Compliance: All compliances were taken from Maj et al [238] (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 [238] (Table 2).
Shunt: Values for QS/QT were a compromise between Maj et al [238] (Table 2, venous admixture) and Torres et al [382] (Table 3) to give realistic PO2 results for the simulated ventilator settings.
Ventilator Settings: All ventilator settings were takeng from Arnal et al [18] (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 [18] 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 [18] (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 [133].

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	Notes
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [18]	11.6	-3.12%	Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [18]	11.6	-3.12%	Rexp
RespiratoryCompliance(mL/cmH2O)	EqualTo 40 [238]	41.2	3.09%	C
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.54 [238]	0.516	-4.49%	VD/VT (determined from blood gas values)
ClinicalShuntFraction	EqualTo 0.2 [238] [382]	0.204	1.83%	QS/QT (determined from blood gas values)
MechanicalVentilator-TidalVolume(mL)	EqualTo 414 [18]	422	1.84%	VT (measured)
BloodPH	[7.28,7.40] [18]	7.36	0.00%	pH
Aorta-Oxygen-PartialPressure(mmHg)	[72.0,88.0] [18]	78.1	0.00%	PaO2
Aorta-CarbonDioxide-PartialPressure(mmHg)	[37.0,46.0] [18]	42.9	0.00%	PaCO2
OxygenSaturation	[0.940,0.970] [133]	0.958	0.00%	SpO2
HorowitzIndex(mmHg)	[232,284] [18]	253	0.00%	PaO2/FiO2
HorowitzIndex(mmHg)	[200,300] [119]	253	0.00%	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)	41.2
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.504
ClinicalShuntFraction	0.204
MechanicalVentilator-TidalVolume(L)	0.422
BloodPH	7.36
Aorta-Oxygen-PartialPressure(mmHg)	78.1
Aorta-CarbonDioxide-PartialPressure(mmHg)	42.9
Aorta-Bicarbonate-Molarity(mEq/L)	26.2
OxygenSaturation	0.958
HorowitzIndex(mmHg)	253
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)	72.8
SystolicArterialPressure(mmHg)	114
DiastolicArterialPressure(mmHg)	73.7
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)	34.7
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	197
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.422
MechanicalVentilator-InspiratoryExpiratoryRatio	0.833
MechanicalVentilator-InspiratoryTidalVolume(L)	0.422
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.750
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.379
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	10.4
PhysiologicDeadSpaceTidalVolumeRatio	0.516
PhysiologicShuntFraction	0.218
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	11.6
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	11.6
TotalRespiratoryModelCompliance(mL/cmH2O)	45.9
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10.0
TotalPositiveEndExpiratoryPressure(cmH2O)	10.4
EndTidalCarbonDioxidePressure(mmHg)	37.7
PhysiologicDeadSpace(mL)	217
AlveolarArterialGradient(mmHg)	114
AlveolarDeadSpace(mL)	96.6
AnatomicDeadSpace(mL)	120
ChestWallCompliance(L/cmH2O)	0.146
FractionOfInspiredOxygen	0.309
LungCompliance(L/cmH2O)	0.0585
VentilationPerfusionRatio	0.794
HeartStrokeVolume(mL)	76.5
HeartEjectionFraction	0.567
BloodVolume(L)	4.14
MeanArterialPressure(mmHg)	95.3
PulsePressure(mmHg)	40.4
CardiacOutput(L/min)	5.57
CarbonDioxideSaturation	0.0434
RespiratoryExchangeRatio	0.811
SystemicVascularResistance(mmHg_s/mL)	0.977
OxygenConsumptionRate(mL/min)	193
CarbonDioxideProductionRate(mL/min)	156
Patient-AlveoliSurfaceArea(m^2)	27.2
Patient-ExpiratoryReserveVolume(L)	0.687
Patient-FunctionalResidualCapacity(L)	1.28
Patient-InspiratoryCapacity(L)	2.45
Patient-InspiratoryReserveVolume(L)	2.05
Patient-ResidualVolume(L)	0.594
Patient-TidalVolumeBaseline(L)	0.406
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	Notes
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [18]	12.4	3.13%	Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [18]	12.4	3.13%	Rexp
RespiratoryCompliance(mL/cmH2O)	EqualTo 35 [238]	35.6	1.81%	C
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.57 [238]	0.554	-2.86%	VD/VT (determined from blood gas values)
ClinicalShuntFraction	EqualTo 0.3 [238] [382]	0.304	1.27%	QS/QT (determined from blood gas values)
MechanicalVentilator-TidalVolume(mL)	EqualTo 396 [18]	405	2.21%	VT (measured)
BloodPH	[7.26,7.41] [18]	7.35	0.00%	pH
Aorta-Oxygen-PartialPressure(mmHg)	[70.0,94.0] [18]	73.2	0.00%	PaO2
Aorta-CarbonDioxide-PartialPressure(mmHg)	[39.0,50.0] [18]	43.8	0.00%	PaCO2
OxygenSaturation	[0.940,0.970] [133]	0.950	0.00%	SpO2
HorowitzIndex(mmHg)	[140,188] [18]	147	0.00%	PaO2/FiO2
HorowitzIndex(mmHg)	[100,200] [119]	147	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
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.521
ClinicalShuntFraction	0.304
MechanicalVentilator-TidalVolume(L)	0.405
BloodPH	7.35
Aorta-Oxygen-PartialPressure(mmHg)	73.2
Aorta-CarbonDioxide-PartialPressure(mmHg)	43.8
Aorta-Bicarbonate-Molarity(mEq/L)	26.2
OxygenSaturation	0.950
HorowitzIndex(mmHg)	147
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)	75.2
SystolicArterialPressure(mmHg)	114
DiastolicArterialPressure(mmHg)	74.2
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)	33.7
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	346
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.405
MechanicalVentilator-InspiratoryExpiratoryRatio	0.845
MechanicalVentilator-InspiratoryTidalVolume(L)	0.405
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.768
MechanicalVentilator-LeakFraction	9.85e-14
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.450
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	12.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	12.4
PhysiologicDeadSpaceTidalVolumeRatio	0.554
PhysiologicShuntFraction	0.320
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)	37.3
PhysiologicDeadSpace(mL)	233
AlveolarArterialGradient(mmHg)	265
AlveolarDeadSpace(mL)	113
AnatomicDeadSpace(mL)	120
ChestWallCompliance(L/cmH2O)	0.134
FractionOfInspiredOxygen	0.499
LungCompliance(L/cmH2O)	0.0495
VentilationPerfusionRatio	0.715
HeartStrokeVolume(mL)	75.5
HeartEjectionFraction	0.563
BloodVolume(L)	4.15
MeanArterialPressure(mmHg)	95.3
PulsePressure(mmHg)	39.8
CardiacOutput(L/min)	5.68
CarbonDioxideSaturation	0.0930
RespiratoryExchangeRatio	0.808
SystemicVascularResistance(mmHg_s/mL)	0.958
OxygenConsumptionRate(mL/min)	189
CarbonDioxideProductionRate(mL/min)	153
Patient-AlveoliSurfaceArea(m^2)	10.9
Patient-ExpiratoryReserveVolume(L)	0.671
Patient-FunctionalResidualCapacity(L)	0.976
Patient-InspiratoryCapacity(L)	2.40
Patient-InspiratoryReserveVolume(L)	1.99
Patient-ResidualVolume(L)	0.305
Patient-TidalVolumeBaseline(L)	0.406
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 [18]	13.1	9.38%		Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [18]	13.1	9.38%		Rexp
RespiratoryCompliance(mL/cmH2O)	EqualTo 33 [238]	32.7	-0.97%		C
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.65 [238]	0.630	-3.14%		VD/VT
ClinicalShuntFraction	EqualTo 0.4 [238] [382]	0.405	1.19%		QS/QT (determined from blood gas values)
MechanicalVentilator-TidalVolume(mL)	EqualTo 396 [18]	402	1.48%		VT (measured)
BloodPH	[7.21,7.34] [18]	7.34	0.02%		pH
Aorta-Oxygen-PartialPressure(mmHg)	[68.0,80.0] [18]	68.5	0.00%		PaO2
Aorta-CarbonDioxide-PartialPressure(mmHg)	[44.0,56.0] [18]	44.8	0.00%		PaCO2
OxygenSaturation	[0.920,0.950] [133]	0.940	0.00%		SpO2
HorowitzIndex(mmHg)	[85.0,100] [18]	85.7	0.00%		PaO2/FiO2
HorowitzIndex(mmHg)	LessThan 100 [119]	85.7		-14.28%	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)	32.7
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.596
ClinicalShuntFraction	0.405
MechanicalVentilator-TidalVolume(L)	0.402
BloodPH	7.34
Aorta-Oxygen-PartialPressure(mmHg)	68.5
Aorta-CarbonDioxide-PartialPressure(mmHg)	44.8
Aorta-Bicarbonate-Molarity(mEq/L)	26.3
OxygenSaturation	0.940
HorowitzIndex(mmHg)	85.7
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)	82.3
SystolicArterialPressure(mmHg)	114
DiastolicArterialPressure(mmHg)	76.7
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)	30.8
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	582
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)	12.7
PhysiologicDeadSpaceTidalVolumeRatio	0.630
PhysiologicShuntFraction	0.421
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	13.1
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	13.1
TotalRespiratoryModelCompliance(mL/cmH2O)	36.2
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	12.0
TotalPositiveEndExpiratoryPressure(cmH2O)	12.8
EndTidalCarbonDioxidePressure(mmHg)	34.5
PhysiologicDeadSpace(mL)	264
AlveolarArterialGradient(mmHg)	504
AlveolarDeadSpace(mL)	144
AnatomicDeadSpace(mL)	120
ChestWallCompliance(L/cmH2O)	0.126
FractionOfInspiredOxygen	0.799
LungCompliance(L/cmH2O)	0.0450
VentilationPerfusionRatio	0.611
HeartStrokeVolume(mL)	69.6
HeartEjectionFraction	0.541
BloodVolume(L)	4.14
MeanArterialPressure(mmHg)	96.1
PulsePressure(mmHg)	36.9
CardiacOutput(L/min)	5.73
CarbonDioxideSaturation	0.141
RespiratoryExchangeRatio	0.810
SystemicVascularResistance(mmHg_s/mL)	0.959
OxygenConsumptionRate(mL/min)	190
CarbonDioxideProductionRate(mL/min)	154
Patient-AlveoliSurfaceArea(m^2)	5.45
Patient-ExpiratoryReserveVolume(L)	0.663
Patient-FunctionalResidualCapacity(L)	0.703
Patient-InspiratoryCapacity(L)	2.37
Patient-InspiratoryReserveVolume(L)	1.96
Patient-ResidualVolume(L)	0.0404
Patient-TidalVolumeBaseline(L)	0.406
Patient-TotalLungCapacity(L)	3.07
Patient-VitalCapacity(L)	3.03

Scenario Output Plots

Figure 4. Select outputs from the scenario.