Moderate ARDS with Tension Pneumothorax

Description

A 25 year-old patient was injured following an explosive detonation. He suffered a traumatic amputation of the right lower extremity below the knee, multiple puncture wounds from fragments in the left lower extremity and lost consciousness at the scene. A tourniquet was applied and the hemorrhage mitigated. Both eardrums were ruptured and his GCS was 12. He underwent a massive transfusion, received 10 units of whole blood, crystalloid infusions and platelets. In the operating room primary control of hemorrhage was achieved and the lower extremity amputation addressed using standard techniques. The patient arrived from the operating room on mechanical ventilation. He was sedated and is not currently triggering the ventilator. The patient is 5'9" tall, weighs 170 lbs and has no known comorbidities or allergies.

Figure 1. Chest radiograph demonstrates subcutaneous air and small pneumomediastinum. There is no pneumothorax.

Segment Validation

Segment 1

Learning Objectives:

Assess baseline status
Recognize moderate ARDS

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-AC	0.488	NA	52	NA	0.6	24	5	0.4

Ventilator alarm settings are:

High PIP = 37 cmH2O (~10 cmH2O above the initial value or a max of 40 cmH2O)
Low MVe = 8.7 L/min (~25% below the initial value)
Low VT = 360 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 488	484	0.735%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	12.4	3.04%	Rinsp for moderate ARDS
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	12.4	3.05%	Rexp for moderate ARDS
RespiratoryCompliance(mL/cmH2O)	EqualTo 40 [304]	41.0	2.42%	C requested by SME for moderate ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.57 [229]	0.553	2.97%	VD/VT for moderate ARDS
ClinicalShuntFraction	[0.300,0.500] [221]	0.357	0.00%	QS/QT for moderate ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	[100,200] [115]	142	0.00%	PaO2/FiO2

Figure 2. Vitals and ventilator monitors for Segment 1.

Table 2. Data requests for Segment 1.

Property Name	Engine Value
Patient-Height(in)	69.0
Patient-IdealBodyWeight(kg)	70.7
InspiratoryRespiratoryResistance(cmH2O_s/L)	12.4
ExpiratoryRespiratoryResistance(cmH2O_s/L)	12.4
RespiratoryCompliance(mL/cmH2O)	41.0
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.467
ClinicalShuntFraction	0.357
MechanicalVentilator-TidalVolume(L)	0.484
BloodPH	7.36
Aorta-Oxygen-PartialPressure(mmHg)	56.9
Aorta-CarbonDioxide-PartialPressure(mmHg)	46.3
Aorta-Bicarbonate-Molarity(mEq/L)	26.2
OxygenSaturation	0.902
HorowitzIndex(mmHg)	142
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.280
MechanicalVentilator-RespirationRate(1/min)	24.0
MechanicalVentilator-MeanAirwayPressure(cmH2O)	9.01
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	27.3
MechanicalVentilator-PlateauPressure(cmH2O)	17.3
HeartRate(1/min)	106
SystolicArterialPressure(mmHg)	111
DiastolicArterialPressure(mmHg)	80.7
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	11.6
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	40.2
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	21.7
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	32.3
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	268
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.484
MechanicalVentilator-InspiratoryExpiratoryRatio	0.316
MechanicalVentilator-InspiratoryTidalVolume(L)	0.484
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.789
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.263
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	5.26
PhysiologicDeadSpaceTidalVolumeRatio	0.553
PhysiologicShuntFraction	0.362
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelCompliance(mL/cmH2O)	48.2
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5.00
TotalPositiveEndExpiratoryPressure(cmH2O)	5.28
EndTidalCarbonDioxidePressure(mmHg)	35.2
PhysiologicDeadSpace(mL)	274
AlveolarArterialGradient(mmHg)	200
AlveolarDeadSpace(mL)	132
AnatomicDeadSpace(mL)	141
ChestWallCompliance(L/cmH2O)	0.120
FractionOfInspiredOxygen	0.400
LungCompliance(L/cmH2O)	0.0643
VentilationPerfusionRatio	1.92
HeartStrokeVolume(mL)	58.5
HeartEjectionFraction	0.481
BloodVolume(L)	5.57
MeanArterialPressure(mmHg)	96.0
PulsePressure(mmHg)	30.0
CardiacOutput(L/min)	6.21
CarbonDioxideSaturation	0.225
RespiratoryExchangeRatio	0.814
SystemicVascularResistance(mmHg_s/mL)	0.882
OxygenConsumptionRate(mL/min)	251
CarbonDioxideProductionRate(mL/min)	205
Patient-AlveoliSurfaceArea(m^2)	12.8
Patient-ExpiratoryReserveVolume(L)	0.820
Patient-FunctionalResidualCapacity(L)	1.21
Patient-InspiratoryCapacity(L)	2.93
Patient-InspiratoryReserveVolume(L)	2.39
Patient-ResidualVolume(L)	0.393
Patient-TidalVolumeBaseline(L)	0.541
Patient-TotalLungCapacity(L)	4.14
Patient-VitalCapacity(L)	3.75

Segment 2

The patient is loaded in the aircraft for transport to trauma center care. Twenty minutes into the transport SpO2 falls and PIP and Pplat are increased. The patient remains sedated and is not triggering the ventilator.

Learning Objectives:

Recognize and treat pneumothorax

Recommended Actions:

Increase in Pplat with same tidal volume indicates decreased compliance
This observation along with diminished breath sounds and hyper-resonance with percussion on one side indicate pneumothorax
Recommend needle decompression

Table 3. Data request validation results for Segment 2.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 488	451	7.98%		VT (measured)
RespiratoryCompliance(mL/cmH2O)	LessThan Segment1 (41.0) [304]	20.8		-49.2%	C
SystolicArterialPressure(mmHg)	LessThan Segment1 (111) [304]	69.8		-37.0%	BP
DiastolicArterialPressure(mmHg)	LessThan Segment1 (80.7) [304]	56.8		-29.7%	BP
Aorta-Oxygen-PartialPressure(mmHg)	LessThan Segment1 (56.9) [185]	26.3		-53.7%	PaO2
OxygenSaturation	LessThan Segment1 (0.902) [304] [308]	0.528		-41.5%	SpO2
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	GreaterThan Segment1 (27.3) [304]	37.6		37.8%	PIP
MechanicalVentilator-PlateauPressure(cmH2O)	GreaterThan Segment1 (17.3) [304]	27.0		56.1%	Pplat

Figure 3. Vitals and ventilator monitors for Segment 2.

Table 4. Data requests for Segment 2.

Property Name	Engine Value
Patient-Height(in)	69.0
Patient-IdealBodyWeight(kg)	70.7
InspiratoryRespiratoryResistance(cmH2O_s/L)	14.8
ExpiratoryRespiratoryResistance(cmH2O_s/L)	14.8
RespiratoryCompliance(mL/cmH2O)	20.8
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.549
ClinicalShuntFraction	0.725
MechanicalVentilator-TidalVolume(L)	0.451
BloodPH	7.35
Aorta-Oxygen-PartialPressure(mmHg)	26.3
Aorta-CarbonDioxide-PartialPressure(mmHg)	47.3
Aorta-Bicarbonate-Molarity(mEq/L)	26.2
OxygenSaturation	0.528
HorowitzIndex(mmHg)	66.1
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0388
MechanicalVentilator-RespirationRate(1/min)	24.4
MechanicalVentilator-MeanAirwayPressure(cmH2O)	10.3
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	37.6
MechanicalVentilator-PlateauPressure(cmH2O)	27.0
HeartRate(1/min)	148
SystolicArterialPressure(mmHg)	69.8
DiastolicArterialPressure(mmHg)	56.8
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	11.0
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	14.8
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	14.8
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	20.5
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	13.8
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	25.8
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	277
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.451
MechanicalVentilator-InspiratoryExpiratoryRatio	0.295
MechanicalVentilator-InspiratoryTidalVolume(L)	0.451
MechanicalVentilator-PeakExpiratoryFlow(L/s)	1.05
MechanicalVentilator-LeakFraction	8.20e-05
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0423
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	5.04
PhysiologicDeadSpaceTidalVolumeRatio	0.553
PhysiologicShuntFraction	0.382
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelCompliance(mL/cmH2O)	42.1
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5.00
TotalPositiveEndExpiratoryPressure(cmH2O)	5.04
EndTidalCarbonDioxidePressure(mmHg)	27.5
PhysiologicDeadSpace(mL)	274
AlveolarArterialGradient(mmHg)	123
AlveolarDeadSpace(mL)	132
AnatomicDeadSpace(mL)	141
ChestWallCompliance(L/cmH2O)	0.0663
FractionOfInspiredOxygen	0.399
LungCompliance(L/cmH2O)	0.0322
VentilationPerfusionRatio	3.19
HeartStrokeVolume(mL)	24.1
HeartEjectionFraction	0.345
BloodVolume(L)	5.59
MeanArterialPressure(mmHg)	63.2
PulsePressure(mmHg)	13.1
CardiacOutput(L/min)	3.58
CarbonDioxideSaturation	0.292
RespiratoryExchangeRatio	0.755
SystemicVascularResistance(mmHg_s/mL)	0.912
OxygenConsumptionRate(mL/min)	243
CarbonDioxideProductionRate(mL/min)	184
Patient-AlveoliSurfaceArea(m^2)	12.8
Patient-ExpiratoryReserveVolume(L)	0.820
Patient-FunctionalResidualCapacity(L)	1.21
Patient-InspiratoryCapacity(L)	2.93
Patient-InspiratoryReserveVolume(L)	2.39
Patient-ResidualVolume(L)	0.393
Patient-TidalVolumeBaseline(L)	0.541
Patient-TotalLungCapacity(L)	4.14
Patient-VitalCapacity(L)	3.75

Segment 3

Needle decompression procedure performed.

Learning Objectives:

Recognize resolution of pneumothorax.

Recommended Actions:

SpO2, breath sounds, plateau pressure indicate pneumothorax resolved

Table 5. Data request validation results for Segment 3.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 488	484	0.765%		VT (measured)
RespiratoryCompliance(mL/cmH2O)	GreaterThan Segment2 (20.8) [304]	40.6		94.9%	C
SystolicArterialPressure(mmHg)	GreaterThan Segment2 (69.8) [304]	111		58.9%	BP
DiastolicArterialPressure(mmHg)	GreaterThan Segment2 (56.8) [304]	80.0		40.9%	BP
Aorta-Oxygen-PartialPressure(mmHg)	GreaterThan Segment2 (26.3) [185]	59.1		125%	PaO2
OxygenSaturation	GreaterThan Segment2 (0.528) [304] [308]	0.906		71.6%	SpO2
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	LessThan Segment2 (37.6) [304]	27.1		-27.9%	PIP
MechanicalVentilator-PlateauPressure(cmH2O)	LessThan Segment2 (27.0) [304]	17.5		-35.3%	Pplat

Figure 4. Vitals and ventilator monitors for Segment 3.

Table 6. Data requests for Segment 3.

Property Name	Engine Value
Patient-Height(in)	69.0
Patient-IdealBodyWeight(kg)	70.7
InspiratoryRespiratoryResistance(cmH2O_s/L)	12.4
ExpiratoryRespiratoryResistance(cmH2O_s/L)	12.4
RespiratoryCompliance(mL/cmH2O)	40.6
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.471
ClinicalShuntFraction	0.335
MechanicalVentilator-TidalVolume(L)	0.484
BloodPH	7.34
Aorta-Oxygen-PartialPressure(mmHg)	59.1
Aorta-CarbonDioxide-PartialPressure(mmHg)	48.5
Aorta-Bicarbonate-Molarity(mEq/L)	26.3
OxygenSaturation	0.906
HorowitzIndex(mmHg)	148
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.325
MechanicalVentilator-RespirationRate(1/min)	24.0
MechanicalVentilator-MeanAirwayPressure(cmH2O)	8.99
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	27.1
MechanicalVentilator-PlateauPressure(cmH2O)	17.5
HeartRate(1/min)	99.8
SystolicArterialPressure(mmHg)	111
DiastolicArterialPressure(mmHg)	80.0
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	11.6
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	39.5
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	21.9
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	33.7
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	267
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.484
MechanicalVentilator-InspiratoryExpiratoryRatio	0.316
MechanicalVentilator-InspiratoryTidalVolume(L)	0.484
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.777
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.252
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	5.25
PhysiologicDeadSpaceTidalVolumeRatio	0.553
PhysiologicShuntFraction	0.341
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelCompliance(mL/cmH2O)	48.3
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	5.00
TotalPositiveEndExpiratoryPressure(cmH2O)	5.33
EndTidalCarbonDioxidePressure(mmHg)	36.8
PhysiologicDeadSpace(mL)	274
AlveolarArterialGradient(mmHg)	196
AlveolarDeadSpace(mL)	132
AnatomicDeadSpace(mL)	141
ChestWallCompliance(L/cmH2O)	0.121
FractionOfInspiredOxygen	0.400
LungCompliance(L/cmH2O)	0.0643
VentilationPerfusionRatio	1.98
HeartStrokeVolume(mL)	60.4
HeartEjectionFraction	0.491
BloodVolume(L)	5.62
MeanArterialPressure(mmHg)	95.8
PulsePressure(mmHg)	31.0
CardiacOutput(L/min)	6.02
CarbonDioxideSaturation	0.302
RespiratoryExchangeRatio	0.812
SystemicVascularResistance(mmHg_s/mL)	0.903
OxygenConsumptionRate(mL/min)	249
CarbonDioxideProductionRate(mL/min)	202
Patient-AlveoliSurfaceArea(m^2)	12.8
Patient-ExpiratoryReserveVolume(L)	0.820
Patient-FunctionalResidualCapacity(L)	1.21
Patient-InspiratoryCapacity(L)	2.93
Patient-InspiratoryReserveVolume(L)	2.39
Patient-ResidualVolume(L)	0.393
Patient-TidalVolumeBaseline(L)	0.541
Patient-TotalLungCapacity(L)	4.14
Patient-VitalCapacity(L)	3.75

Scenario Output Plots

Figure 5. Select outputs from the scenario.