Mild TBI with worsening ARDS

Description

A 25 year-old active duty Marine was involved in a training accident where a Humvee was wrecked. She has a mild traumatic brain injury, flail chest and pulmonary contusions. The patient is 5'7" tall, weighs 170 lbs and has no known allergies. She is sedated and not triggering the ventilator.

Figure 1. Chest radiograph demonstrates bilateral patchy opacities and ground glass appearance.

Segment Validation

Segment 1

Learning Objectives:

Evaluate ventilatory status

Recommended Actions:

None

Ventilator settings are:

Mode	VT (L)	PIP (cmH2O)	Flow (L/min)	I:E	TI (s)	RR (bpm)	PEEP (cmH2O)	FiO2
VC-CMV	0.450	NA	53	NA	0.53	27	8	0.21

Table 1. Data request validation results for Segment 1.

Property Name	Validation	Engine Value	Percent Error	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 450	440	2.30%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	11.5	4.48%	Rinsp for mild ARDS
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	11.5	4.48%	Rexp for mild ARDS
RespiratoryCompliance(mL/cmH2O)	EqualTo 50 [305]	51.7	3.40%	C requested by SME for mild ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.54 [230]	0.516	4.60%	VD/VT for mild ARDS
ClinicalShuntFraction	[0.200,0.400] [222]	0.205	0.00%	QS/QT for mild ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	[200,300] [115]	292	0.00%	PaO2/FiO2 for mild ARDS

Figure 2. Vitals and ventilator monitors for Segment 1.

Table 2. Data requests for Segment 1.

Property Name	Engine Value
Patient-Height(in)	67.0
Patient-IdealBodyWeight(kg)	61.6
InspiratoryRespiratoryResistance(cmH2O_s/L)	11.5
ExpiratoryRespiratoryResistance(cmH2O_s/L)	11.5
RespiratoryCompliance(mL/cmH2O)	51.7
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.477
ClinicalShuntFraction	0.205
MechanicalVentilator-TidalVolume(L)	0.440
BloodPH	7.39
Aorta-Oxygen-PartialPressure(mmHg)	61.2
Aorta-CarbonDioxide-PartialPressure(mmHg)	42.3
Aorta-Bicarbonate-Molarity(mEq/L)	26.0
OxygenSaturation	0.926
HorowitzIndex(mmHg)	292
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.541
MechanicalVentilator-RespirationRate(1/min)	26.8
MechanicalVentilator-MeanAirwayPressure(cmH2O)	11.5
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	26.9
MechanicalVentilator-PlateauPressure(cmH2O)	17.0
HeartRate(1/min)	110
SystolicArterialPressure(mmHg)	125
DiastolicArterialPressure(mmHg)	74.5
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	11.8
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	11.5
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	11.5
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	51.4
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	23.3
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	29.8
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	126
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.440
MechanicalVentilator-InspiratoryExpiratoryRatio	0.318
MechanicalVentilator-InspiratoryTidalVolume(L)	0.440
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.650
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.480
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	8.48
PhysiologicDeadSpaceTidalVolumeRatio	0.516
ShuntFraction	0.204
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	11.5
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	11.5
TotalRespiratoryModelCompliance(mL/cmH2O)	61.2
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.55
EndTidalCarbonDioxidePressure(mmHg)	32.4
PhysiologicDeadSpace(mL)	222
AlveolarArterialGradient(mmHg)	58.3
AlveolarDeadSpace(mL)	99.2
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.160
FractionOfInspiredOxygen	0.209
LungCompliance(L/cmH2O)	0.0790
VentilationPerfusionRatio	2.64
HeartStrokeVolume(mL)	51.1
HeartEjectionFraction	0.422
BloodVolume(L)	5.53
MeanArterialPressure(mmHg)	99.9
PulsePressure(mmHg)	50.6
CardiacOutput(L/min)	5.62
CarbonDioxideSaturation	0.0284
RespiratoryExchangeRatio	0.815
SystemicVascularResistance(mmHg_s/mL)	1.02
OxygenConsumptionRate(mL/min)	220
CarbonDioxideProductionRate(mL/min)	180
Patient-AlveoliSurfaceArea(m^2)	28.0
Patient-ExpiratoryReserveVolume(L)	0.738
Patient-FunctionalResidualCapacity(L)	1.38
Patient-InspiratoryCapacity(L)	2.63
Patient-InspiratoryReserveVolume(L)	2.16
Patient-ResidualVolume(L)	0.647
Patient-TidalVolumeBaseline(L)	0.479
Patient-TotalLungCapacity(L)	4.02
Patient-VitalCapacity(L)	3.37

Segment 2

The patient is loaded in the aircraft for transport to SAMMC. Halfway through the flight the ventilator starts alarming high inspiratory pressure. The SpO2 falls while PIP and Pplat increase. The patient is now triggering the ventilator at a much higher rate.
Learning Objectives:

Recognize worsening oxygenation
Respond to high pressure alarm

Recommended Actions:

Decrease tidal volume

Table 3. Data request validation results for Segment 2.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 450	445	1.07%		VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment1 (11.5) [17]	16.1		40.6%	Rinsp for increased PIP
ExpiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment1 (11.5) [17]	16.1		40.7%	Rexp for increased PIP
RespiratoryCompliance(mL/cmH2O)	EqualTo 30 [305]	28.4	5.53%		C requested by SME for severe ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.65 [230]	0.630	3.20%		VD/VT for severe ARDS
ClinicalShuntFraction	GreaterThan 0.4 [222]	0.412		3.08%	QS/QT for severe ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	LessThan 100 [115]	147		47.3%	PaO2/FiO2 for severe ARDS

Figure 3. Vitals and ventilator monitors for Segment 2.

Table 4. Data requests for Segment 2.

Property Name	Engine Value
Patient-Height(in)	67.0
Patient-IdealBodyWeight(kg)	61.6
InspiratoryRespiratoryResistance(cmH2O_s/L)	16.1
ExpiratoryRespiratoryResistance(cmH2O_s/L)	16.1
RespiratoryCompliance(mL/cmH2O)	28.4
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.685
ClinicalShuntFraction	0.412
MechanicalVentilator-TidalVolume(L)	0.445
BloodPH	7.41
Aorta-Oxygen-PartialPressure(mmHg)	30.9
Aorta-CarbonDioxide-PartialPressure(mmHg)	40.7
Aorta-Bicarbonate-Molarity(mEq/L)	25.9
OxygenSaturation	0.673
HorowitzIndex(mmHg)	147
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.142
MechanicalVentilator-RespirationRate(1/min)	41.1
MechanicalVentilator-MeanAirwayPressure(cmH2O)	15.5
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	38.6
MechanicalVentilator-PlateauPressure(cmH2O)	26.1
HeartRate(1/min)	165
SystolicArterialPressure(mmHg)	121
DiastolicArterialPressure(mmHg)	81.2
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	18.3
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	16.0
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	16.2
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	27.7
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	14.6
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	19.0
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	143
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.445
MechanicalVentilator-InspiratoryExpiratoryRatio	0.587
MechanicalVentilator-InspiratoryTidalVolume(L)	0.445
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.994
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	2.07
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	10.1
PhysiologicDeadSpaceTidalVolumeRatio	0.630
ShuntFraction	0.417
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelCompliance(mL/cmH2O)	33.2
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.14
EndTidalCarbonDioxidePressure(mmHg)	21.0
PhysiologicDeadSpace(mL)	271
AlveolarArterialGradient(mmHg)	107
AlveolarDeadSpace(mL)	148
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.120
FractionOfInspiredOxygen	0.210
LungCompliance(L/cmH2O)	0.0405
VentilationPerfusionRatio	5.17
HeartStrokeVolume(mL)	36.5
HeartEjectionFraction	0.337
BloodVolume(L)	5.54
MeanArterialPressure(mmHg)	101
PulsePressure(mmHg)	40.0
CardiacOutput(L/min)	6.03
CarbonDioxideSaturation	0.0318
RespiratoryExchangeRatio	0.787
SystemicVascularResistance(mmHg_s/mL)	0.955
OxygenConsumptionRate(mL/min)	192
CarbonDioxideProductionRate(mL/min)	151
Patient-AlveoliSurfaceArea(m^2)	5.59
Patient-ExpiratoryReserveVolume(L)	0.672
Patient-FunctionalResidualCapacity(L)	0.703
Patient-InspiratoryCapacity(L)	2.40
Patient-InspiratoryReserveVolume(L)	1.92
Patient-ResidualVolume(L)	0.0315
Patient-TidalVolumeBaseline(L)	0.479
Patient-TotalLungCapacity(L)	3.10
Patient-VitalCapacity(L)	3.07

Segment 3

Ventialtor settings are changed. Decrease VT to prevent premature cycling by high-pressure alarm.

Learning Objectives:

Evaluate effects of changes

Recommended Actions:

Increase PEEP to improve oxygenation
Increase FiO2 to get SpO2 88-95%

Ventilator settings are updated to:

TV = 450 mL -> 350 mL

Mode	VT (L)	PIP (cmH2O)	Flow (L/min)	I:E	TI (s)	RR (bpm)	PEEP (cmH2O)	FiO2
VC-CMV	0.350	NA	42	NA	0.52	27	8	0.21

Table 5. Data request validation results for Segment 3.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 350	339	3.09%		VT (measured)
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	LessThan Segment2 (38.6) [186]	37.9		-1.90%	PaO2

Figure 4. Vitals and ventilator monitors for Segment 3.

Table 6. Data requests for Segment 3.

Property Name	Engine Value
Patient-Height(in)	67.0
Patient-IdealBodyWeight(kg)	61.6
InspiratoryRespiratoryResistance(cmH2O_s/L)	16.1
ExpiratoryRespiratoryResistance(cmH2O_s/L)	16.6
RespiratoryCompliance(mL/cmH2O)	27.7
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.588
ClinicalShuntFraction	0.416
MechanicalVentilator-TidalVolume(L)	0.339
BloodPH	7.39
Aorta-Oxygen-PartialPressure(mmHg)	25.2
Aorta-CarbonDioxide-PartialPressure(mmHg)	42.7
Aorta-Bicarbonate-Molarity(mEq/L)	26.0
OxygenSaturation	0.531
HorowitzIndex(mmHg)	121
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0169
MechanicalVentilator-RespirationRate(1/min)	30.6
MechanicalVentilator-MeanAirwayPressure(cmH2O)	13.1
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	37.9
MechanicalVentilator-PlateauPressure(cmH2O)	20.8
HeartRate(1/min)	167
SystolicArterialPressure(mmHg)	122
DiastolicArterialPressure(mmHg)	81.5
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	10.4
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	15.8
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	16.6
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	27.5
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	11.4
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	24.0
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	135
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.457
MechanicalVentilator-InspiratoryExpiratoryRatio	0.361
MechanicalVentilator-InspiratoryTidalVolume(L)	0.339
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.957
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.494
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	8.49
PhysiologicDeadSpaceTidalVolumeRatio	0.630
ShuntFraction	0.416
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelCompliance(mL/cmH2O)	34.1
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.02
EndTidalCarbonDioxidePressure(mmHg)	26.2
PhysiologicDeadSpace(mL)	271
AlveolarArterialGradient(mmHg)	104
AlveolarDeadSpace(mL)	148
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.111
FractionOfInspiredOxygen	0.209
LungCompliance(L/cmH2O)	0.0403
VentilationPerfusionRatio	3.85
HeartStrokeVolume(mL)	36.5
HeartEjectionFraction	0.336
BloodVolume(L)	5.55
MeanArterialPressure(mmHg)	101
PulsePressure(mmHg)	40.6
CardiacOutput(L/min)	6.11
CarbonDioxideSaturation	0.0432
RespiratoryExchangeRatio	0.778
SystemicVascularResistance(mmHg_s/mL)	0.948
OxygenConsumptionRate(mL/min)	185
CarbonDioxideProductionRate(mL/min)	144
Patient-AlveoliSurfaceArea(m^2)	5.59
Patient-ExpiratoryReserveVolume(L)	0.672
Patient-FunctionalResidualCapacity(L)	0.703
Patient-InspiratoryCapacity(L)	2.40
Patient-InspiratoryReserveVolume(L)	1.92
Patient-ResidualVolume(L)	0.0315
Patient-TidalVolumeBaseline(L)	0.479
Patient-TotalLungCapacity(L)	3.10
Patient-VitalCapacity(L)	3.07

Segment 4

Ventialtor settings are changed. PEEP and FiO2 increased.

Learning Objectives:

Evaluate effects of changes

Recommended Actions:

None

Ventilator settings are updated to:

FIO2 = 0.50->1.00
PEEP = 8->12 cmH2O

Mode	VT (L)	PIP (cmH2O)	Flow (L/min)	I:E	TI (s)	RR (bpm)	PEEP (cmH2O)	FiO2
VC-CMV	0.350	NA	42	NA	0.52	27	12	1.00

Table 7. Data request validation results for Segment 4.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 350	340	3.03%		VT (measured)
Aorta-Oxygen-PartialPressure(mmHg)	GreaterThan 2 [186]	69.5		3.38e+03%	PaO2

Figure 5. Vitals and ventilator monitors for Segment 4.

Table 8. Data requests for Segment 4.

Property Name	Engine Value
Patient-Height(in)	67.0
Patient-IdealBodyWeight(kg)	61.6
InspiratoryRespiratoryResistance(cmH2O_s/L)	16.1
ExpiratoryRespiratoryResistance(cmH2O_s/L)	16.1
RespiratoryCompliance(mL/cmH2O)	28.4
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.596
ClinicalShuntFraction	0.415
MechanicalVentilator-TidalVolume(L)	0.340
BloodPH	7.30
Aorta-Oxygen-PartialPressure(mmHg)	69.5
Aorta-CarbonDioxide-PartialPressure(mmHg)	53.7
Aorta-Bicarbonate-Molarity(mEq/L)	26.5
OxygenSaturation	0.931
HorowitzIndex(mmHg)	69.7
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.314
MechanicalVentilator-RespirationRate(1/min)	37.5
MechanicalVentilator-MeanAirwayPressure(cmH2O)	16.0
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	30.4
MechanicalVentilator-PlateauPressure(cmH2O)	25.2
HeartRate(1/min)	95.3
SystolicArterialPressure(mmHg)	132
DiastolicArterialPressure(mmHg)	71.0
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	12.7
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	16.0
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	16.1
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	28.2
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	18.5
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	29.8
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	739
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.340
MechanicalVentilator-InspiratoryExpiratoryRatio	0.481
MechanicalVentilator-InspiratoryTidalVolume(L)	0.340
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.562
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.12
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	12.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	13.1
PhysiologicDeadSpaceTidalVolumeRatio	0.630
ShuntFraction	0.423
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelCompliance(mL/cmH2O)	34.5
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	12.0
TotalPositiveEndExpiratoryPressure(cmH2O)	12.3
EndTidalCarbonDioxidePressure(mmHg)	34.4
PhysiologicDeadSpace(mL)	271
AlveolarArterialGradient(mmHg)	661
AlveolarDeadSpace(mL)	148
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.135
FractionOfInspiredOxygen	0.998
LungCompliance(L/cmH2O)	0.0402
VentilationPerfusionRatio	3.86
HeartStrokeVolume(mL)	59.5
HeartEjectionFraction	0.453
BloodVolume(L)	5.63
MeanArterialPressure(mmHg)	102
PulsePressure(mmHg)	61.1
CardiacOutput(L/min)	5.67
CarbonDioxideSaturation	0.426
RespiratoryExchangeRatio	0.825
SystemicVascularResistance(mmHg_s/mL)	1.03
OxygenConsumptionRate(mL/min)	231
CarbonDioxideProductionRate(mL/min)	191
Patient-AlveoliSurfaceArea(m^2)	5.59
Patient-ExpiratoryReserveVolume(L)	0.672
Patient-FunctionalResidualCapacity(L)	0.703
Patient-InspiratoryCapacity(L)	2.40
Patient-InspiratoryReserveVolume(L)	1.92
Patient-ResidualVolume(L)	0.0315
Patient-TidalVolumeBaseline(L)	0.479
Patient-TotalLungCapacity(L)	3.10
Patient-VitalCapacity(L)	3.07

Scenario Output Plots

Figure 6. Select outputs from the scenario.