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]	51.8	3.51%	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]	0.195	2.30%	QS/QT for mild ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	[200,300] [115]	294	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)	51.8
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.476
ClinicalShuntFraction	0.195
MechanicalVentilator-TidalVolume(L)	0.440
BloodPH	7.39
Aorta-Oxygen-PartialPressure(mmHg)	61.6
Aorta-CarbonDioxide-PartialPressure(mmHg)	42.1
Aorta-Bicarbonate-Molarity(mEq/L)	26.0
OxygenSaturation	0.928
HorowitzIndex(mmHg)	294
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)	111
SystolicArterialPressure(mmHg)	125
DiastolicArterialPressure(mmHg)	74.8
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)	29.7
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
PhysiologicShuntFraction	0.196
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	11.5
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	11.5
TotalRespiratoryModelCompliance(mL/cmH2O)	61.1
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.55
EndTidalCarbonDioxidePressure(mmHg)	32.4
PhysiologicDeadSpace(mL)	222
AlveolarArterialGradient(mmHg)	57.9
AlveolarDeadSpace(mL)	99.2
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.160
FractionOfInspiredOxygen	0.209
LungCompliance(L/cmH2O)	0.0790
VentilationPerfusionRatio	2.19
HeartStrokeVolume(mL)	50.0
HeartEjectionFraction	0.418
BloodVolume(L)	5.53
MeanArterialPressure(mmHg)	99.8
PulsePressure(mmHg)	49.8
CardiacOutput(L/min)	5.53
CarbonDioxideSaturation	0.0284
RespiratoryExchangeRatio	0.813
SystemicVascularResistance(mmHg_s/mL)	1.03
OxygenConsumptionRate(mL/min)	217
CarbonDioxideProductionRate(mL/min)	176
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	1.06%		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		40.6%	Rexp for increased PIP
RespiratoryCompliance(mL/cmH2O)	EqualTo 30 [305]	28.4	5.51%		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]	0.406		1.54%	QS/QT for severe ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	LessThan 100 [115]	148		47.8%	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	0.687
ClinicalShuntFraction	0.406
MechanicalVentilator-TidalVolume(L)	0.445
BloodPH	7.41
Aorta-Oxygen-PartialPressure(mmHg)	31.0
Aorta-CarbonDioxide-PartialPressure(mmHg)	40.7
Aorta-Bicarbonate-Molarity(mEq/L)	25.9
OxygenSaturation	0.675
HorowitzIndex(mmHg)	148
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.138
MechanicalVentilator-RespirationRate(1/min)	41.1
MechanicalVentilator-MeanAirwayPressure(cmH2O)	15.5
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	38.6
MechanicalVentilator-PlateauPressure(cmH2O)	26.1
HeartRate(1/min)	170
SystolicArterialPressure(mmHg)	120
DiastolicArterialPressure(mmHg)	80.7
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	18.3
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	16.1
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	16.1
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	27.8
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	14.6
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	18.9
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)	2.06
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	10.1
PhysiologicDeadSpaceTidalVolumeRatio	0.630
PhysiologicShuntFraction	0.407
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelCompliance(mL/cmH2O)	33.8
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.14
EndTidalCarbonDioxidePressure(mmHg)	20.9
PhysiologicDeadSpace(mL)	271
AlveolarArterialGradient(mmHg)	108
AlveolarDeadSpace(mL)	148
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.121
FractionOfInspiredOxygen	0.210
LungCompliance(L/cmH2O)	0.0405
VentilationPerfusionRatio	3.20
HeartStrokeVolume(mL)	34.5
HeartEjectionFraction	0.328
BloodVolume(L)	5.54
MeanArterialPressure(mmHg)	99.9
PulsePressure(mmHg)	39.2
CardiacOutput(L/min)	5.88
CarbonDioxideSaturation	0.0317
RespiratoryExchangeRatio	0.790
SystemicVascularResistance(mmHg_s/mL)	0.972
OxygenConsumptionRate(mL/min)	195
CarbonDioxideProductionRate(mL/min)	154
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	3.13%		VT (measured)
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	LessThan Segment2 (38.6) [186]	37.8		-1.94%	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)	16.1
RespiratoryCompliance(mL/cmH2O)	27.7
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.588
ClinicalShuntFraction	0.411
MechanicalVentilator-TidalVolume(L)	0.339
BloodPH	7.39
Aorta-Oxygen-PartialPressure(mmHg)	25.3
Aorta-CarbonDioxide-PartialPressure(mmHg)	42.8
Aorta-Bicarbonate-Molarity(mEq/L)	26.0
OxygenSaturation	0.532
HorowitzIndex(mmHg)	121
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.625
MechanicalVentilator-RespirationRate(1/min)	30.6
MechanicalVentilator-MeanAirwayPressure(cmH2O)	13.1
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	37.8
MechanicalVentilator-PlateauPressure(cmH2O)	20.8
HeartRate(1/min)	172
SystolicArterialPressure(mmHg)	121
DiastolicArterialPressure(mmHg)	82.2
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	10.4
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	16.1
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	16.1
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	27.6
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)	0.956
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.489
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	8.49
PhysiologicDeadSpaceTidalVolumeRatio	0.630
PhysiologicShuntFraction	0.412
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelCompliance(mL/cmH2O)	33.6
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.63
EndTidalCarbonDioxidePressure(mmHg)	26.2
PhysiologicDeadSpace(mL)	271
AlveolarArterialGradient(mmHg)	102
AlveolarDeadSpace(mL)	148
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.111
FractionOfInspiredOxygen	0.209
LungCompliance(L/cmH2O)	0.0403
VentilationPerfusionRatio	2.36
HeartStrokeVolume(mL)	35.1
HeartEjectionFraction	0.327
BloodVolume(L)	5.55
MeanArterialPressure(mmHg)	101
PulsePressure(mmHg)	38.7
CardiacOutput(L/min)	6.03
CarbonDioxideSaturation	0.0447
RespiratoryExchangeRatio	0.774
SystemicVascularResistance(mmHg_s/mL)	0.960
OxygenConsumptionRate(mL/min)	182
CarbonDioxideProductionRate(mL/min)	141
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	2.96%		VT (measured)
Aorta-Oxygen-PartialPressure(mmHg)	GreaterThan Segment3 (25.3) [186]	68.6		172%	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)	28.6
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.594
ClinicalShuntFraction	0.408
MechanicalVentilator-TidalVolume(L)	0.340
BloodPH	7.30
Aorta-Oxygen-PartialPressure(mmHg)	68.6
Aorta-CarbonDioxide-PartialPressure(mmHg)	53.2
Aorta-Bicarbonate-Molarity(mEq/L)	26.5
OxygenSaturation	0.930
HorowitzIndex(mmHg)	68.8
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.216
MechanicalVentilator-RespirationRate(1/min)	37.0
MechanicalVentilator-MeanAirwayPressure(cmH2O)	16.0
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	30.2
MechanicalVentilator-PlateauPressure(cmH2O)	25.1
HeartRate(1/min)	101
SystolicArterialPressure(mmHg)	130
DiastolicArterialPressure(mmHg)	72.8
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	12.6
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	16.1
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	16.1
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	28.2
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	18.6
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	29.6
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	739
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.340
MechanicalVentilator-InspiratoryExpiratoryRatio	0.473
MechanicalVentilator-InspiratoryTidalVolume(L)	0.340
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.558
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.07
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	12.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	13.1
PhysiologicDeadSpaceTidalVolumeRatio	0.630
PhysiologicShuntFraction	0.413
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	16.1
TotalRespiratoryModelCompliance(mL/cmH2O)	34.2
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	12.0
TotalPositiveEndExpiratoryPressure(cmH2O)	12.2
EndTidalCarbonDioxidePressure(mmHg)	34.1
PhysiologicDeadSpace(mL)	271
AlveolarArterialGradient(mmHg)	663
AlveolarDeadSpace(mL)	148
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.118
FractionOfInspiredOxygen	0.998
LungCompliance(L/cmH2O)	0.0405
VentilationPerfusionRatio	2.33
HeartStrokeVolume(mL)	54.9
HeartEjectionFraction	0.437
BloodVolume(L)	5.63
MeanArterialPressure(mmHg)	102
PulsePressure(mmHg)	57.0
CardiacOutput(L/min)	5.55
CarbonDioxideSaturation	0.417
RespiratoryExchangeRatio	0.819
SystemicVascularResistance(mmHg_s/mL)	1.05
OxygenConsumptionRate(mL/min)	224
CarbonDioxideProductionRate(mL/min)	184
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.