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. @subsection autotoc_md739 Segment Validation @subsubsection autotoc_md740 Segment 1 Learning Objectives: - Evaluate ventilatory status Recommended Actions: - None <br> Ventilator settings are: <table class="markdownTable"> <tr class="markdownTableHead"> <th class="markdownTableHeadNone"> 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	-1.90%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [18]	11.5	-4.43%	Rinsp for mild ARDS
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [18]	11.5	-4.43%	Rexp for mild ARDS
RespiratoryCompliance(mL/cmH2O)	EqualTo 50 [316]	52.3	4.50%	C requested by SME for mild ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.54 [238]	0.516	-4.50%	VD/VT for mild ARDS
ClinicalShuntFraction	[0.200,0.400] [229]	0.215	0.00%	QS/QT for mild ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	[200,300] [119]	181	-9.75%	PaO2/FiO2 for mild ARDS

Figure 1. 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)	52.3
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.413
ClinicalShuntFraction	0.215
MechanicalVentilator-TidalVolume(L)	0.441
BloodPH	7.36
Aorta-Oxygen-PartialPressure(mmHg)	90.1
Aorta-CarbonDioxide-PartialPressure(mmHg)	42.9
Aorta-Bicarbonate-Molarity(mEq/L)	26.2
OxygenSaturation	0.971
HorowitzIndex(mmHg)	181
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)	91.0
SystolicArterialPressure(mmHg)	129
DiastolicArterialPressure(mmHg)	69.3
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)	34.0
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	0.220
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	11.5
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	11.5
TotalRespiratoryModelCompliance(mL/cmH2O)	57.9
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
TotalPositiveEndExpiratoryPressure(cmH2O)	8.54
EndTidalCarbonDioxidePressure(mmHg)	36.7
PhysiologicDeadSpace(mL)	222
AlveolarArterialGradient(mmHg)	249
AlveolarDeadSpace(mL)	99.2
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.159
FractionOfInspiredOxygen	0.499
LungCompliance(L/cmH2O)	0.0790
VentilationPerfusionRatio	1.01
HeartStrokeVolume(mL)	59.2
HeartEjectionFraction	0.459
BloodVolume(L)	5.53
MeanArterialPressure(mmHg)	99.7
PulsePressure(mmHg)	59.9
CardiacOutput(L/min)	5.39
CarbonDioxideSaturation	0.0431
RespiratoryExchangeRatio	0.809
SystemicVascularResistance(mmHg_s/mL)	1.06
OxygenConsumptionRate(mL/min)	228
CarbonDioxideProductionRate(mL/min)	184
Patient-AlveoliSurfaceArea(m^2)	28.0
Patient-ExpiratoryReserveVolume(L)	0.738
Patient-FunctionalResidualCapacity(L)	1.38
Patient-InspiratoryCapacity(L)	2.63
Patient-InspiratoryReserveVolume(L)	2.18
Patient-ResidualVolume(L)	0.647
Patient-TidalVolumeBaseline(L)	0.459
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.

Learning Objectives:

Recognize worsening oxygenation
Respond to high pressure alarm

Recommended Actions:

Evaluate for pneumothorax
Decrease tidal volume to get acceptable delta P
Increase respiratory rate to get same minute ventilation
Increase rate and minute ventilation alarm thresholds

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)	417		-5.64%	VT reduced by PIP alarm cycling
InspiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment1 (11.5) [18]	22.8		99.15%	Rinsp for increased PIP
ExpiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment1 (11.5) [18]	22.8		99.15%	Rexp for increased PIP
RespiratoryCompliance(mL/cmH2O)	EqualTo 40 [316]	41.0	2.40%		C requested by SME for moderate ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.57 [238]	0.554	-2.87%		VD/VT for moderate ARDS
OxygenSaturation	LessThan Segment1 (0.971) [316] [320]	0.930		-4.22%	SpO2
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	GreaterThan Segment1 (23.4) [316]	33.2		41.84%	PIP
MechanicalVentilator-PlateauPressure(cmH2O)	GreaterThan Segment1 (17.0) [316]	19.5		15.05%	Pplat
ClinicalShuntFraction	[0.300,0.500] [229]	0.319	0.00%		QS/QT for moderate ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	[100,200] [119]	130	0.00%		PaO2/FiO2 for moderate ARDS
HighPressureAlarmTriggered-FinalState	EqualTo True [316]	True	Pass		High PIP Alarm

Figure 2. 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)	41.0
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.435
ClinicalShuntFraction	0.319
MechanicalVentilator-TidalVolume(L)	0.417
BloodPH	7.35
Aorta-Oxygen-PartialPressure(mmHg)	64.7
Aorta-CarbonDioxide-PartialPressure(mmHg)	44.2
Aorta-Bicarbonate-Molarity(mEq/L)	26.3
OxygenSaturation	0.930
HorowitzIndex(mmHg)	130
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.97
MechanicalVentilator-RespirationRate(1/min)	24.6
MechanicalVentilator-MeanAirwayPressure(cmH2O)	14.1
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	33.2
MechanicalVentilator-PlateauPressure(cmH2O)	19.5
HeartRate(1/min)	110
SystolicArterialPressure(mmHg)	127
DiastolicArterialPressure(mmHg)	73.7
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	9.95
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	22.8
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	22.8
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	40.7
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	16.2
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	34.0
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	343
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.407
MechanicalVentilator-InspiratoryExpiratoryRatio	0.435
MechanicalVentilator-InspiratoryTidalVolume(L)	0.417
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.458
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.60
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	9.60
PhysiologicDeadSpaceTidalVolumeRatio	0.554
PhysiologicShuntFraction	0.322
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	22.8
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	22.8
TotalRespiratoryModelCompliance(mL/cmH2O)	48.1
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.01
TotalPositiveEndExpiratoryPressure(cmH2O)	9.98
EndTidalCarbonDioxidePressure(mmHg)	37.9
PhysiologicDeadSpace(mL)	239
AlveolarArterialGradient(mmHg)	276
AlveolarDeadSpace(mL)	116
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.143
FractionOfInspiredOxygen	0.499
LungCompliance(L/cmH2O)	0.0591
VentilationPerfusionRatio	0.782
HeartStrokeVolume(mL)	49.8
HeartEjectionFraction	0.414
BloodVolume(L)	5.54
MeanArterialPressure(mmHg)	100
PulsePressure(mmHg)	52.9
CardiacOutput(L/min)	5.47
CarbonDioxideSaturation	0.112
RespiratoryExchangeRatio	0.804
SystemicVascularResistance(mmHg_s/mL)	1.05
OxygenConsumptionRate(mL/min)	223
CarbonDioxideProductionRate(mL/min)	179
Patient-AlveoliSurfaceArea(m^2)	11.2
Patient-ExpiratoryReserveVolume(L)	0.707
Patient-FunctionalResidualCapacity(L)	1.04
Patient-InspiratoryCapacity(L)	2.52
Patient-InspiratoryReserveVolume(L)	2.06
Patient-ResidualVolume(L)	0.333
Patient-TidalVolumeBaseline(L)	0.459
Patient-TotalLungCapacity(L)	3.56
Patient-VitalCapacity(L)	3.23

Segment 3

Ventilator settings are changed. Decrease VT to prevent premature cycling by high-pressure alarm with increased RR to maintain alveolar ventilation.

Learning Objectives:

Evaluate status

Recommended Actions:

None

Ventilator settings are updated to:

TV = 450 mL -> 350 mL
Flow = 35 L/min -> 28 L/min
RR = 20 bpm -> 34 bpm

Ventilator alarm settings are updated to:

Low VT = 263 mL (~25% below the initial value)
High RR = 40 bpm (~10 bpm above the initial value or a max of 40 bpm)

Table 5. Data request validation results for Segment 3.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 350	346	-1.13%		VT (measured)
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	LessThan Segment2 (33.2) [316]	31.6		-4.86%	PIP
HighPressureAlarmTriggered-FinalState	EqualTo False [316]	False	Pass		High PIP Alarm

Figure 3. 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)	43.3
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.500
ClinicalShuntFraction	0.269
MechanicalVentilator-TidalVolume(L)	0.346
BloodPH	7.34
Aorta-Oxygen-PartialPressure(mmHg)	72.2
Aorta-CarbonDioxide-PartialPressure(mmHg)	44.7
Aorta-Bicarbonate-Molarity(mEq/L)	26.3
OxygenSaturation	0.947
HorowitzIndex(mmHg)	145
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	4.92
MechanicalVentilator-RespirationRate(1/min)	33.7
MechanicalVentilator-MeanAirwayPressure(cmH2O)	16.7
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	31.6
MechanicalVentilator-PlateauPressure(cmH2O)	19.0
HeartRate(1/min)	98.4
SystolicArterialPressure(mmHg)	128
DiastolicArterialPressure(mmHg)	72.0
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	11.7
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	22.8
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	22.8
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	43.2
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	14.7
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	32.1
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	346
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.346
MechanicalVentilator-InspiratoryExpiratoryRatio	0.816
MechanicalVentilator-InspiratoryTidalVolume(L)	0.346
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.509
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	2.97
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.00
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	11.0
PhysiologicDeadSpaceTidalVolumeRatio	0.554
PhysiologicShuntFraction	0.274
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	22.8
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	22.8
TotalRespiratoryModelCompliance(mL/cmH2O)	48.4
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8.02
TotalPositiveEndExpiratoryPressure(cmH2O)	12.9
EndTidalCarbonDioxidePressure(mmHg)	37.5
PhysiologicDeadSpace(mL)	239
AlveolarArterialGradient(mmHg)	269
AlveolarDeadSpace(mL)	116
AnatomicDeadSpace(mL)	123
ChestWallCompliance(L/cmH2O)	0.163
FractionOfInspiredOxygen	0.498
LungCompliance(L/cmH2O)	0.0594
VentilationPerfusionRatio	0.722
HeartStrokeVolume(mL)	54.3
HeartEjectionFraction	0.437
BloodVolume(L)	5.54
MeanArterialPressure(mmHg)	101
PulsePressure(mmHg)	56.5
CardiacOutput(L/min)	5.34
CarbonDioxideSaturation	0.138
RespiratoryExchangeRatio	0.806
SystemicVascularResistance(mmHg_s/mL)	1.08
OxygenConsumptionRate(mL/min)	225
CarbonDioxideProductionRate(mL/min)	181
Patient-AlveoliSurfaceArea(m^2)	11.2
Patient-ExpiratoryReserveVolume(L)	0.707
Patient-FunctionalResidualCapacity(L)	1.04
Patient-InspiratoryCapacity(L)	2.52
Patient-InspiratoryReserveVolume(L)	2.06
Patient-ResidualVolume(L)	0.333
Patient-TidalVolumeBaseline(L)	0.459
Patient-TotalLungCapacity(L)	3.56
Patient-VitalCapacity(L)	3.23

Scenario Output Plots

Figure 4. Select outputs from the scenario.