Mild TBI with worsening ARDS

Description

A 25 year-old patient 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-AC	0.450	NA	35	NA	0.8	24	8	0.5

Ventilator alarm settings are:

High PIP = 33 cmH2O (~10 cmH2O above the initial value or a max of 40 cmH2O)
Low MVe = 6.8 L/min (~25% below the initial value)
Low VT = 330 mL (~25% below the initial value)
High RR = 34 bpm (~10 bpm above the initial value or a max of 40 bpm)

Table 1. Data request validation results for Segment 1.

Property Name	Validation	Engine Value	Percent Error	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 450	441	1.92%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	11.5	4.53%	Rinsp for mild ARDS
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	11.5	4.53%	Rexp for mild ARDS
RespiratoryCompliance(mL/cmH2O)	EqualTo 50 [305]	52.6	5.13%	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]	0.192	4.07%	QS/QT for mild ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	[200,300] [115]	196	1.91%	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)	52.6
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.456
ClinicalShuntFraction	0.192
MechanicalVentilator-TidalVolume(L)	0.441
BloodPH	7.38
Aorta-Oxygen-PartialPressure(mmHg)	98.0
Aorta-CarbonDioxide-PartialPressure(mmHg)	43.8
Aorta-Bicarbonate-Molarity(mEq/L)	26.1
OxygenSaturation	0.977
HorowitzIndex(mmHg)	196
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.536
MechanicalVentilator-RespirationRate(1/min)	24.0
MechanicalVentilator-MeanAirwayPressure(cmH2O)	11.6
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	23.4
MechanicalVentilator-PlateauPressure(cmH2O)	17.0
HeartRate(1/min)	90.5
SystolicArterialPressure(mmHg)	129
DiastolicArterialPressure(mmHg)	69.5
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	10.6
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	11.5
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	11.5
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	51.9
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	28.6
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	33.7
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	345
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.441
MechanicalVentilator-InspiratoryExpiratoryRatio	0.471
MechanicalVentilator-InspiratoryTidalVolume(L)	0.441
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.650
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.490
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	8.49
PhysiologicDeadSpaceTidalVolumeRatio	0.516
PhysiologicShuntFraction	0.194
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	11.5
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	11.5
TotalRespiratoryModelCompliance(mL/cmH2O)	58.5
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.54
EndTidalCarbonDioxidePressure(mmHg)	36.9
PhysiologicDeadSpace(mL)	222
AlveolarArterialGradient(mmHg)	238
AlveolarDeadSpace(mL)	99.2
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.163
FractionOfInspiredOxygen	0.499
LungCompliance(L/cmH2O)	0.0790
VentilationPerfusionRatio	2.03
HeartStrokeVolume(mL)	59.1
HeartEjectionFraction	0.459
BloodVolume(L)	5.53
MeanArterialPressure(mmHg)	99.7
PulsePressure(mmHg)	59.6
CardiacOutput(L/min)	5.35
CarbonDioxideSaturation	0.0987
RespiratoryExchangeRatio	0.821
SystemicVascularResistance(mmHg_s/mL)	1.07
OxygenConsumptionRate(mL/min)	227
CarbonDioxideProductionRate(mL/min)	186
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 the medical center. 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:

Respond to increased PIP
Recognize dyssynchrony

Recommended Actions:

Evaluate for pneumothorax
Decrease RR to remove dyssynchrony

Table 3. Data request validation results for Segment 2.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	LessThan Segment1 (441)	438		-0.754%	VT reduced by PIP alarm cycling
InspiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment1 (11.5) [17]	22.8		99.1%	Rinsp for increased PIP
ExpiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment1 (11.5) [17]	22.8		99.1%	Rexp for increased PIP
RespiratoryCompliance(mL/cmH2O)	EqualTo 40 [305]	42.6	6.37%		C requested by SME for moderate ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.57 [230]	0.554	2.91%		VD/VT for moderate ARDS
OxygenSaturation	LessThan Segment1 (0.977) [305] [309]	0.948		-2.96%	SpO2
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	GreaterThan Segment1 (23.4) [305]	27.2		15.8%	PIP
MechanicalVentilator-PlateauPressure(cmH2O)	GreaterThan Segment1 (17.0) [305]	20.2		18.7%	Pplat
ClinicalShuntFraction	[0.300,0.500] [222]	0.264	12.7%		QS/QT for moderate ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	[100,200] [115]	144	0.00%		PaO2/FiO2 for moderate 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)	22.8
ExpiratoryRespiratoryResistance(cmH2O_s/L)	22.8
RespiratoryCompliance(mL/cmH2O)	42.6
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.562
ClinicalShuntFraction	0.264
MechanicalVentilator-TidalVolume(L)	0.438
BloodPH	7.37
Aorta-Oxygen-PartialPressure(mmHg)	72.2
Aorta-CarbonDioxide-PartialPressure(mmHg)	44.9
Aorta-Bicarbonate-Molarity(mEq/L)	26.1
OxygenSaturation	0.948
HorowitzIndex(mmHg)	144
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	2.97
MechanicalVentilator-RespirationRate(1/min)	24.0
MechanicalVentilator-MeanAirwayPressure(cmH2O)	13.8
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	27.2
MechanicalVentilator-PlateauPressure(cmH2O)	20.2
HeartRate(1/min)	95.2
SystolicArterialPressure(mmHg)	129
DiastolicArterialPressure(mmHg)	70.2
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	10.5
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	22.8
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	22.8
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	42.2
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	22.8
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	32.7
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	345
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.442
MechanicalVentilator-InspiratoryExpiratoryRatio	0.471
MechanicalVentilator-InspiratoryTidalVolume(L)	0.438
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.416
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.78
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	9.78
PhysiologicDeadSpaceTidalVolumeRatio	0.554
PhysiologicShuntFraction	0.265
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	22.8
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	22.8
TotalRespiratoryModelCompliance(mL/cmH2O)	47.5
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.01
TotalPositiveEndExpiratoryPressure(cmH2O)	11.0
EndTidalCarbonDioxidePressure(mmHg)	36.1
PhysiologicDeadSpace(mL)	239
AlveolarArterialGradient(mmHg)	267
AlveolarDeadSpace(mL)	116
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.161
FractionOfInspiredOxygen	0.499
LungCompliance(L/cmH2O)	0.0594
VentilationPerfusionRatio	2.00
HeartStrokeVolume(mL)	57.4
HeartEjectionFraction	0.450
BloodVolume(L)	5.54
MeanArterialPressure(mmHg)	100
PulsePressure(mmHg)	59.2
CardiacOutput(L/min)	5.46
CarbonDioxideSaturation	0.158
RespiratoryExchangeRatio	0.818
SystemicVascularResistance(mmHg_s/mL)	1.05
OxygenConsumptionRate(mL/min)	223
CarbonDioxideProductionRate(mL/min)	183
Patient-AlveoliSurfaceArea(m^2)	11.2
Patient-ExpiratoryReserveVolume(L)	0.707
Patient-FunctionalResidualCapacity(L)	1.04
Patient-InspiratoryCapacity(L)	2.52
Patient-InspiratoryReserveVolume(L)	2.04
Patient-ResidualVolume(L)	0.333
Patient-TidalVolumeBaseline(L)	0.479
Patient-TotalLungCapacity(L)	3.56
Patient-VitalCapacity(L)	3.23

Segment 3

Ventilator settings are changed. Decrease RR to remove dyssynchrony.

Learning Objectives:

Evaluate status

Recommended Actions:

None

Ventilator settings are updated to:

RR = 24 bpm -> 12 bpm

Table 5. Data request validation results for Segment 3.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
HighPressureAlarmTriggered-FinalState	EqualTo False [305]	False	Pass		High PIP Alarm

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)	22.8
ExpiratoryRespiratoryResistance(cmH2O_s/L)	22.8
RespiratoryCompliance(mL/cmH2O)	40.6
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.518
ClinicalShuntFraction	0.278
MechanicalVentilator-TidalVolume(L)	0.446
BloodPH	7.36
Aorta-Oxygen-PartialPressure(mmHg)	70.2
Aorta-CarbonDioxide-PartialPressure(mmHg)	45.4
Aorta-Bicarbonate-Molarity(mEq/L)	26.2
OxygenSaturation	0.944
HorowitzIndex(mmHg)	141
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.176
MechanicalVentilator-RespirationRate(1/min)	23.8
MechanicalVentilator-MeanAirwayPressure(cmH2O)	12.5
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	30.6
MechanicalVentilator-PlateauPressure(cmH2O)	20.7
HeartRate(1/min)	97.3
SystolicArterialPressure(mmHg)	129
DiastolicArterialPressure(mmHg)	71.3
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	10.6
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	22.8
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	22.8
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	40.6
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	19.8
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	32.8
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	346
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.446
MechanicalVentilator-InspiratoryExpiratoryRatio	0.465
MechanicalVentilator-InspiratoryTidalVolume(L)	0.446
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.512
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.72
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	9.72
PhysiologicDeadSpaceTidalVolumeRatio	0.554
PhysiologicShuntFraction	0.283
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	22.8
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	22.8
TotalRespiratoryModelCompliance(mL/cmH2O)	46.6
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.18
EndTidalCarbonDioxidePressure(mmHg)	36.1
PhysiologicDeadSpace(mL)	239
AlveolarArterialGradient(mmHg)	263
AlveolarDeadSpace(mL)	116
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.143
FractionOfInspiredOxygen	0.499
LungCompliance(L/cmH2O)	0.0591
VentilationPerfusionRatio	2.00
HeartStrokeVolume(mL)	56.1
HeartEjectionFraction	0.444
BloodVolume(L)	5.55
MeanArterialPressure(mmHg)	101
PulsePressure(mmHg)	58.1
CardiacOutput(L/min)	5.45
CarbonDioxideSaturation	0.183
RespiratoryExchangeRatio	0.816
SystemicVascularResistance(mmHg_s/mL)	1.06
OxygenConsumptionRate(mL/min)	220
CarbonDioxideProductionRate(mL/min)	180
Patient-AlveoliSurfaceArea(m^2)	11.2
Patient-ExpiratoryReserveVolume(L)	0.707
Patient-FunctionalResidualCapacity(L)	1.04
Patient-InspiratoryCapacity(L)	2.52
Patient-InspiratoryReserveVolume(L)	2.04
Patient-ResidualVolume(L)	0.333
Patient-TidalVolumeBaseline(L)	0.479
Patient-TotalLungCapacity(L)	3.56
Patient-VitalCapacity(L)	3.23

Scenario Output Plots

Figure 5. Select outputs from the scenario.