Mild ARDS with Progressive Fall in Oxygenation

Description

A 22 year-old soldier was involved in a motor vehicle crash with rollover and ejection from the vehicle. He suffered multiple rib fractures, a right femur fracture, multiple lacerations and pulmonary contusion. He underwent internal fixation of the femur fracture, received 4 units of whole blood, had a chest tube placed for a small hemothorax and returned from the operating room on mechanical ventilation. The patient is sedated and is not currently triggering the ventilator. Intraoperatively 3 L of crystalloids were administered. The patient is 6'2'' tall, weighs 200 lbs and has no known comorbidities or allergies. Chest radiograph demonstrates bi-basilar early consolidation, presence of the chest tube and pulmonary contusion.

Figure 1. Chest radiograph demonstrates bi-basilar early consolidation, presence of the chest tube and pulmonary contusion.

Segment Validation

Segment 1

Learning Objectives:

Recognize mild ARDS
Recognize acceptable ventilator settings

Recommended Actions:

None

Ventilator settings are (VT Target = 6.9 mL/kg (ideal)):

Mode	VT (L)	PIP (cmH2O)	Flow (L/min)	I:E	TI (s)	RR (bpm)	PEEP (cmH2O)	FiO2
VC-CMV	0.567	NA	59	NA	0.6	20	5	0.4

Table 1. Data request validation results for Segment 1.

Property Name	Validation	Engine Value	Percent Error	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 567 [17]	550.4	3.0%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	11.4	5.1%	Rinsp for mild ARDS
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	11.4	5.1%	Rexp for mild ARDS
RespiratoryCompliance(mL/cmH2O)	EqualTo 40 [229]	41.66	4.1%	C for mild ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.54 [229]	0.4772	12.4%	VD/VT for mild ARDS
ShuntFraction	EqualTo 0.2 [229]	0.1998	0.1%	QS/QT for mild ARDS
HorowitzIndex(mmHg)	[200,300] [115]	210.8	0.0%	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)	74
Patient-IdealBodyWeight(kg)	82.2
InspiratoryRespiratoryResistance(cmH2O_s/L)	11.4
ExpiratoryRespiratoryResistance(cmH2O_s/L)	11.4
RespiratoryCompliance(mL/cmH2O)	41.7
PhysiologicDeadSpaceTidalVolumeRatio	0.477
ShuntFraction	0.2
MechanicalVentilator-TidalVolume(L)	0.55
BloodPH	7.25
Aorta-Oxygen-PartialPressure(mmHg)	84.3
Aorta-CarbonDioxide-PartialPressure(mmHg)	60.5
Aorta-Bicarbonate-Molarity(mEq/L)	26.8
OxygenSaturation	0.951
HorowitzIndex(mmHg)	211
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0808
MechanicalVentilator-RespirationRate(1/min)	20
MechanicalVentilator-MeanAirwayPressure(cmH2O)	8.54
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	28.9
MechanicalVentilator-PlateauPressure(cmH2O)	18.8
HeartRate(1/min)	69.3
SystolicArterialPressure(mmHg)	115
DiastolicArterialPressure(mmHg)	73.4
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	11
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	11.4
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	11.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	40
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	23
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	42.3
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	257
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.55
MechanicalVentilator-InspiratoryExpiratoryRatio	0.25
MechanicalVentilator-InspiratoryTidalVolume(L)	0.55
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.929
MechanicalVentilator-LeakFraction	6.19E-14
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0715
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	5.07
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5
TotalPositiveEndExpiratoryPressure(cmH2O)	5.08
EndTidalCarbonDioxidePressure(mmHg)	45.1
PhysiologicDeadSpace(mL)	275
AlveolarArterialGradient(mmHg)	162
AlveolarDeadSpace(mL)	110
AnatomicDeadSpace(mL)	164
ChestWallCompliance(L/cmH2O)	0.125
FractionOfInspiredOxygen	0.4
LungCompliance(L/cmH2O)	0.0637
VentilationPerfusionRatio	2.28
HeartStrokeVolume(mL)	87.1
HeartEjectionFraction	0.573
BloodVolume(L)	6.65
MeanArterialPressure(mmHg)	95.7
PulsePressure(mmHg)	41.8
CardiacOutput(L/min)	6.04
CarbonDioxideSaturation	0.193
RespiratoryExchangeRatio	0.828
SystemicVascularResistance(mmHg_s/mL)	0.902
OxygenConsumptionRate(mL/min)	310
CarbonDioxideProductionRate(mL/min)	256
Patient-AlveoliSurfaceArea(m^2)	43.5
Patient-ExpiratoryReserveVolume(L)	0.953
Patient-FunctionalResidualCapacity(L)	1.82
Patient-InspiratoryCapacity(L)	3.4
Patient-InspiratoryReserveVolume(L)	2.8
Patient-ResidualVolume(L)	0.87
Patient-TidalVolumeBaseline(L)	0.599
Patient-TotalLungCapacity(L)	5.23
Patient-VitalCapacity(L)	4.35

Segment 2

The patient is loaded in the aircraft for transport to level III care. Twenty minutes into the transport, SpO2 falls and both PIP and Pplat are increased. The patient is triggering the ventilator.
Learning Objectives:

Recognize worsening ARDS (moderate)
Adjust vent settings for safety

Recommended Actions:

Increase FiO2 to 0.5
Decrease VT to 490 mL to get acceptable DP

Table 3. Data request validation results for Segment 2.

Property Name	Validation	Engine Value	Percent Error	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 567 [17]	555.4	2.1%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	12.37	3.1%	Rinsp for moderate ARDS
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	12.38	3.1%	Rexp for moderate ARDS
RespiratoryCompliance(mL/cmH2O)	EqualTo 35 [229]	34.31	2.0%	C for moderate ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.57 [229]	0.5531	3.0%	VD/VT for moderate ARDS
ShuntFraction	EqualTo 0.3 [229]	0.3906	26.2%	QS/QT for moderate ARDS
HorowitzIndex(mmHg)	[100,200] [115]	139.9	0.0%	PaO2/FiO2

Figure 3. Vitals and ventilator monitors for Segment 2.

Table 4. Data requests for Segment 2.

Property Name	Engine Value
Patient-Height(in)	74
Patient-IdealBodyWeight(kg)	82.2
InspiratoryRespiratoryResistance(cmH2O_s/L)	12.4
ExpiratoryRespiratoryResistance(cmH2O_s/L)	12.4
RespiratoryCompliance(mL/cmH2O)	34.3
PhysiologicDeadSpaceTidalVolumeRatio	0.553
ShuntFraction	0.391
MechanicalVentilator-TidalVolume(L)	0.555
BloodPH	7.28
Aorta-Oxygen-PartialPressure(mmHg)	55.9
Aorta-CarbonDioxide-PartialPressure(mmHg)	56.2
Aorta-Bicarbonate-Molarity(mEq/L)	26.6
OxygenSaturation	0.874
HorowitzIndex(mmHg)	140
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0996
MechanicalVentilator-RespirationRate(1/min)	25.9
MechanicalVentilator-MeanAirwayPressure(cmH2O)	9.08
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	28.1
MechanicalVentilator-PlateauPressure(cmH2O)	21.9
HeartRate(1/min)	102
SystolicArterialPressure(mmHg)	113
DiastolicArterialPressure(mmHg)	80.3
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	14.4
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	12.3
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	33.4
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	24
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	33
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	269
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.555
MechanicalVentilator-InspiratoryExpiratoryRatio	0.349
MechanicalVentilator-InspiratoryTidalVolume(L)	0.555
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.809
MechanicalVentilator-LeakFraction	0
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.26
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	5.26
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5
TotalPositiveEndExpiratoryPressure(cmH2O)	5.1
EndTidalCarbonDioxidePressure(mmHg)	35.7
PhysiologicDeadSpace(mL)	318
AlveolarArterialGradient(mmHg)	204
AlveolarDeadSpace(mL)	154
AnatomicDeadSpace(mL)	164
ChestWallCompliance(L/cmH2O)	0.12
FractionOfInspiredOxygen	0.4
LungCompliance(L/cmH2O)	0.0494
VentilationPerfusionRatio	3.48
HeartStrokeVolume(mL)	66.3
HeartEjectionFraction	0.498
BloodVolume(L)	6.68
MeanArterialPressure(mmHg)	97.1
PulsePressure(mmHg)	32.4
CardiacOutput(L/min)	6.75
CarbonDioxideSaturation	0.204
RespiratoryExchangeRatio	0.824
SystemicVascularResistance(mmHg_s/mL)	0.82
OxygenConsumptionRate(mL/min)	304
CarbonDioxideProductionRate(mL/min)	250
Patient-AlveoliSurfaceArea(m^2)	14.9
Patient-ExpiratoryReserveVolume(L)	0.919
Patient-FunctionalResidualCapacity(L)	1.34
Patient-InspiratoryCapacity(L)	3.28
Patient-InspiratoryReserveVolume(L)	2.69
Patient-ResidualVolume(L)	0.418
Patient-TidalVolumeBaseline(L)	0.599
Patient-TotalLungCapacity(L)	4.62
Patient-VitalCapacity(L)	4.2

Segment 3

Patient transport continues.

Learning Objectives:

Recognize need to increase PEEP to keep on PEEP matrix

Recommended Actions:

Increase PEEP to 10 to keep on PEEP matrix

Ventilator settings are updated to:

FiO2: 0.4 -> 0.5
VT: 567 -> 490 mL
Flow: 59 -> 50 L/min

Mode	VT (L)	PIP (cmH2O)	Flow (L/min)	I:E	TI (s)	RR (bpm)	PEEP (cmH2O)	FiO2
VC-CMV	0.490	NA	50	NA	0.6	20	5	0.5

Table 5. Data request validation results for Segment 3.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 490 [186]	471.6	3.8%		VT (measured)
Aorta-Oxygen-PartialPressure(mmHg)	GreaterThan Segment 2 (55.91) [304] [308]	60.85		8.8%	PaO2
ShuntFraction	EqualTo Segment 2 (0.3906) [304] [308]	0.3915	0.2%		QS/QT

Figure 4. Vitals and ventilator monitors for Segment 3.

Table 6. Data requests for Segment 3.

Property Name	Engine Value
Patient-Height(in)	74
Patient-IdealBodyWeight(kg)	82.2
InspiratoryRespiratoryResistance(cmH2O_s/L)	12.4
ExpiratoryRespiratoryResistance(cmH2O_s/L)	12.4
RespiratoryCompliance(mL/cmH2O)	35.8
PhysiologicDeadSpaceTidalVolumeRatio	0.553
ShuntFraction	0.391
MechanicalVentilator-TidalVolume(L)	0.472
BloodPH	7.23
Aorta-Oxygen-PartialPressure(mmHg)	60.8
Aorta-CarbonDioxide-PartialPressure(mmHg)	63.7
Aorta-Bicarbonate-Molarity(mEq/L)	26.9
OxygenSaturation	0.884
HorowitzIndex(mmHg)	122
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.21
MechanicalVentilator-RespirationRate(1/min)	30.9
MechanicalVentilator-MeanAirwayPressure(cmH2O)	8.99
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	24.8
MechanicalVentilator-PlateauPressure(cmH2O)	18.6
HeartRate(1/min)	92.4
SystolicArterialPressure(mmHg)	113
DiastolicArterialPressure(mmHg)	78.4
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	14.6
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	12.3
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	36.5
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	23.8
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	32.7
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	345
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.472
MechanicalVentilator-InspiratoryExpiratoryRatio	0.448
MechanicalVentilator-InspiratoryTidalVolume(L)	0.472
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.751
MechanicalVentilator-LeakFraction	0
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.668
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	5.67
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5
TotalPositiveEndExpiratoryPressure(cmH2O)	5.21
EndTidalCarbonDioxidePressure(mmHg)	36.2
PhysiologicDeadSpace(mL)	318
AlveolarArterialGradient(mmHg)	275
AlveolarDeadSpace(mL)	154
AnatomicDeadSpace(mL)	164
ChestWallCompliance(L/cmH2O)	0.113
FractionOfInspiredOxygen	0.499
LungCompliance(L/cmH2O)	0.0492
VentilationPerfusionRatio	3.57
HeartStrokeVolume(mL)	72.3
HeartEjectionFraction	0.522
BloodVolume(L)	6.72
MeanArterialPressure(mmHg)	96.4
PulsePressure(mmHg)	34.8
CardiacOutput(L/min)	6.68
CarbonDioxideSaturation	0.193
RespiratoryExchangeRatio	0.827
SystemicVascularResistance(mmHg_s/mL)	0.821
OxygenConsumptionRate(mL/min)	309
CarbonDioxideProductionRate(mL/min)	256
Patient-AlveoliSurfaceArea(m^2)	14.9
Patient-ExpiratoryReserveVolume(L)	0.919
Patient-FunctionalResidualCapacity(L)	1.34
Patient-InspiratoryCapacity(L)	3.28
Patient-InspiratoryReserveVolume(L)	2.69
Patient-ResidualVolume(L)	0.418
Patient-TidalVolumeBaseline(L)	0.599
Patient-TotalLungCapacity(L)	4.62
Patient-VitalCapacity(L)	4.2

Segment 4

Patient transport has ended.

Learning Objectives:

Recognize improvement due to change in vent settings
Consider changing mode to address work shifting

Recommended Actions:

None

Ventilator settings are updated to:

PEEP: 5 -> 10 cmH2O

Mode	VT (L)	PIP (cmH2O)	Flow (L/min)	I:E	TI (s)	RR (bpm)	PEEP (cmH2O)	FiO2
VC-CMV	0.567	NA	50	NA	0.6	20	10	0.5

Table 7. Data request validation results for Segment 4.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 490 [186]	471.7	3.8%		VT (measured)
RespiratoryCompliance(mL/cmH2O)	GreaterThan Segment 3 (35.84) [229]	36.05		0.6%	C
Aorta-CarbonDioxide-PartialPressure(mmHg)	EqualTo Segment 3 (63.71) [254]	65.26	2.4%		PaCO2
Aorta-Oxygen-PartialPressure(mmHg)	GreaterThan Segment 3 (60.85) [186]	65.69		8.0%	PaO2
HorowitzIndex(mmHg)	GreaterThan Segment 3 (121.9) [186]	131.6		8.0%	PaO2/FiO2
ShuntFraction	LessThan Segment 3 (0.3915) [186]	0.3444		-12.0%	QS/QT

Figure 5. Vitals and ventilator monitors for Segment 4.

Table 8. Data requests for Segment 4.

Property Name	Engine Value
Patient-Height(in)	74
Patient-IdealBodyWeight(kg)	82.2
InspiratoryRespiratoryResistance(cmH2O_s/L)	12.4
ExpiratoryRespiratoryResistance(cmH2O_s/L)	12.4
RespiratoryCompliance(mL/cmH2O)	36
PhysiologicDeadSpaceTidalVolumeRatio	0.553
ShuntFraction	0.344
MechanicalVentilator-TidalVolume(L)	0.472
BloodPH	7.22
Aorta-Oxygen-PartialPressure(mmHg)	65.7
Aorta-CarbonDioxide-PartialPressure(mmHg)	65.3
Aorta-Bicarbonate-Molarity(mEq/L)	27
OxygenSaturation	0.901
HorowitzIndex(mmHg)	132
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.144
MechanicalVentilator-RespirationRate(1/min)	29.4
MechanicalVentilator-MeanAirwayPressure(cmH2O)	13.6
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	28.9
MechanicalVentilator-PlateauPressure(cmH2O)	23.6
HeartRate(1/min)	89.5
SystolicArterialPressure(mmHg)	114
DiastolicArterialPressure(mmHg)	77.4
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	13.9
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	12.3
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	36
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	25
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	35.1
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	345
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.472
MechanicalVentilator-InspiratoryExpiratoryRatio	0.417
MechanicalVentilator-InspiratoryTidalVolume(L)	0.472
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.691
MechanicalVentilator-LeakFraction	2.53E-06
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.517
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	10.5
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10
TotalPositiveEndExpiratoryPressure(cmH2O)	10.1
EndTidalCarbonDioxidePressure(mmHg)	38.9
PhysiologicDeadSpace(mL)	318
AlveolarArterialGradient(mmHg)	263
AlveolarDeadSpace(mL)	154
AnatomicDeadSpace(mL)	164
ChestWallCompliance(L/cmH2O)	0.138
FractionOfInspiredOxygen	0.499
LungCompliance(L/cmH2O)	0.0495
VentilationPerfusionRatio	3.14
HeartStrokeVolume(mL)	76
HeartEjectionFraction	0.534
BloodVolume(L)	6.74
MeanArterialPressure(mmHg)	96.3
PulsePressure(mmHg)	36.4
CardiacOutput(L/min)	6.8
CarbonDioxideSaturation	0.19
RespiratoryExchangeRatio	0.828
SystemicVascularResistance(mmHg_s/mL)	0.806
OxygenConsumptionRate(mL/min)	310
CarbonDioxideProductionRate(mL/min)	257
Patient-AlveoliSurfaceArea(m^2)	14.9
Patient-ExpiratoryReserveVolume(L)	0.919
Patient-FunctionalResidualCapacity(L)	1.34
Patient-InspiratoryCapacity(L)	3.28
Patient-InspiratoryReserveVolume(L)	2.69
Patient-ResidualVolume(L)	0.418
Patient-TidalVolumeBaseline(L)	0.599
Patient-TotalLungCapacity(L)	4.62
Patient-VitalCapacity(L)	4.2

Scenario Output Plots

Figure 6. Select outputs from the scenario.