Hypoxemic Respiratory Failure - Pneumonia

Description

A 23 year old soldier suffered developed shortness of breath, substernal chest pain and a productive cough following burn pit exposure. He was started on broad spectrum antibiotics and steroids for a suspected respiratory tract infection. Initial chest x-ray demonstrated some minor hilar infiltrates. On day 5 of his antibiotic course he developed worsening dyspnea, was febrile to 39.5 degC, a breathing frequency of 32 bpm and his SpO2 was 91%. He was placed on high flow nasal cannula at 50% and 40 L/min. After 12 hours he was intubated. The soldier is 6'3'' and weighs 215 lbs. Suctioning reveals thick, tenacious, brownish-yellow secretions. Therapeutic bronchoscopy is performed and 15-20 ml secretions removed and sent for culture and sensitivity. Initial gram stain suggests acinetobacter baumanni. Antibiotics are changed to a carbapenem. He is scheduled for CCATT to definitive care in the morning.

Figure 1. Chest radiograph demonstrates bilateral infiltrates with right middle and lower lobe consolidation, but no signs of barotrauma.

Segment Validation

Segment 1

Diagnosis: Mild Pneumonia.
After intubation he is on mechanical ventilation and remains sedated with a RASS of -2.
Ventilator settings are (delivered VT of 520 ml):

Mode	VT (L)	PIP (cmH2O)	Flow (L/min)	I:E	TI (s)	RR (bpm)	PEEP (cmH2O)	FiO2
PC-CMV	NA	24	NA	NA	0.5	10	8	0.60

Vital signs demonstrate a hyperdynamic response to illness blood gas suggests mild ARDS.

Table 1. Data request validation results for Segment 1.

Property Name	Validation	Engine Value	Percent Error	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 520 [17]	521.5	0.3%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	11.63	3.2%	Rinsp for moderate ARDS
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	11.63	3.2%	Rexp for moderate ARDS
RespiratoryCompliance(mL/cmH2O)	EqualTo 35 [229]	40.14	13.7%	C for moderate ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.57 [229]	0.5151	10.1%	VD/VT for moderate ARDS
ShuntFraction	EqualTo 0.3 [229]	0.2443	20.4%	QS/QT for moderate ARDS
HorowitzIndex(mmHg)	[100,200] [115]	157.5	0.0%	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)	75
Patient-IdealBodyWeight(kg)	84.5
InspiratoryRespiratoryResistance(cmH2O_s/L)	11.6
ExpiratoryRespiratoryResistance(cmH2O_s/L)	11.6
RespiratoryCompliance(mL/cmH2O)	40.1
PhysiologicDeadSpaceTidalVolumeRatio	0.515
ShuntFraction	0.244
MechanicalVentilator-TidalVolume(L)	0.522
BloodPH	7.2
Aorta-Oxygen-PartialPressure(mmHg)	94.4
Aorta-CarbonDioxide-PartialPressure(mmHg)	69.2
Aorta-Bicarbonate-Molarity(mEq/L)	27.1
OxygenSaturation	0.958
HorowitzIndex(mmHg)	157
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.191
MechanicalVentilator-RespirationRate(1/min)	21.4
MechanicalVentilator-MeanAirwayPressure(cmH2O)	10.7
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	23.9
MechanicalVentilator-PlateauPressure(cmH2O)	21.1
HeartRate(1/min)	117
SystolicArterialPressure(mmHg)	110
DiastolicArterialPressure(mmHg)	81.2
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	11.2
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	11.6
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	11.6
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	40
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	32.8
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	45.1
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	410
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.522
MechanicalVentilator-InspiratoryExpiratoryRatio	0.217
MechanicalVentilator-InspiratoryTidalVolume(L)	0.522
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.543
MechanicalVentilator-LeakFraction	0
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0924
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	8.09
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8
TotalPositiveEndExpiratoryPressure(cmH2O)	8.19
EndTidalCarbonDioxidePressure(mmHg)	49
PhysiologicDeadSpace(mL)	305
AlveolarArterialGradient(mmHg)	300
AlveolarDeadSpace(mL)	136
AnatomicDeadSpace(mL)	169
ChestWallCompliance(L/cmH2O)	0.131
FractionOfInspiredOxygen	0.599
LungCompliance(L/cmH2O)	0.0585
VentilationPerfusionRatio	2.18
HeartStrokeVolume(mL)	58.3
HeartEjectionFraction	0.463
BloodVolume(L)	7.09
MeanArterialPressure(mmHg)	96.2
PulsePressure(mmHg)	29.3
CardiacOutput(L/min)	6.81
CarbonDioxideSaturation	0.181
RespiratoryExchangeRatio	0.831
SystemicVascularResistance(mmHg_s/mL)	0.805
OxygenConsumptionRate(mL/min)	330
CarbonDioxideProductionRate(mL/min)	274
Patient-AlveoliSurfaceArea(m^2)	38.3
Patient-ExpiratoryReserveVolume(L)	0.967
Patient-FunctionalResidualCapacity(L)	1.8
Patient-InspiratoryCapacity(L)	3.45
Patient-InspiratoryReserveVolume(L)	2.84
Patient-ResidualVolume(L)	0.836
Patient-TidalVolumeBaseline(L)	0.618
Patient-TotalLungCapacity(L)	5.26
Patient-VitalCapacity(L)	4.42

Segment 2

Diagnosis: Increased Secretions.
The patient is loaded onto the aircraft for transfer to Level III care. During transport the patient becomes agitated and respiratory rate increases, SpO2 has fallen, and ETCO2 has increased.

Table 3. Data request validation results for Segment 2.

Property Name	Validation	Engine Value	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	LessThan Segment 1 (521.5) [17]	266.4	-48.9%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment 1 (11.63) [304] [308]	26.64	129.1%	Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment 1 (11.63) [304] [308]	26.64	129.1%	Rexp

Figure 3. Vitals and ventilator monitors for Segment 2.

Table 4. Data requests for Segment 2.

Property Name	Engine Value
Patient-Height(in)	75
Patient-IdealBodyWeight(kg)	84.5
InspiratoryRespiratoryResistance(cmH2O_s/L)	26.6
ExpiratoryRespiratoryResistance(cmH2O_s/L)	26.6
RespiratoryCompliance(mL/cmH2O)	42.2
PhysiologicDeadSpaceTidalVolumeRatio	0.515
ShuntFraction	0.212
MechanicalVentilator-TidalVolume(L)	0.266
BloodPH	7.08
Aorta-Oxygen-PartialPressure(mmHg)	112
Aorta-CarbonDioxide-PartialPressure(mmHg)	93.3
Aorta-Bicarbonate-Molarity(mEq/L)	27.8
OxygenSaturation	0.962
HorowitzIndex(mmHg)	191
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0406
MechanicalVentilator-RespirationRate(1/min)	33.3
MechanicalVentilator-MeanAirwayPressure(cmH2O)	12.2
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	24
MechanicalVentilator-PlateauPressure(cmH2O)	16.3
HeartRate(1/min)	142
SystolicArterialPressure(mmHg)	109
DiastolicArterialPressure(mmHg)	83.6
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	8.88
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	26.6
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	26.7
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	42.1
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	16.7
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	50.4
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	395
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.266
MechanicalVentilator-InspiratoryExpiratoryRatio	0.385
MechanicalVentilator-InspiratoryTidalVolume(L)	0.266
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.338
MechanicalVentilator-LeakFraction	0.000195
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.99
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	9.99
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8
TotalPositiveEndExpiratoryPressure(cmH2O)	8.04
EndTidalCarbonDioxidePressure(mmHg)	59.7
PhysiologicDeadSpace(mL)	305
AlveolarArterialGradient(mmHg)	239
AlveolarDeadSpace(mL)	136
AnatomicDeadSpace(mL)	169
ChestWallCompliance(L/cmH2O)	0.153
FractionOfInspiredOxygen	0.586
LungCompliance(L/cmH2O)	0.0585
VentilationPerfusionRatio	1.64
HeartStrokeVolume(mL)	48.3
HeartEjectionFraction	0.411
BloodVolume(L)	7.1
MeanArterialPressure(mmHg)	96.3
PulsePressure(mmHg)	25.3
CardiacOutput(L/min)	6.83
CarbonDioxideSaturation	0.157
RespiratoryExchangeRatio	0.835
SystemicVascularResistance(mmHg_s/mL)	0.804
OxygenConsumptionRate(mL/min)	338
CarbonDioxideProductionRate(mL/min)	282
Patient-AlveoliSurfaceArea(m^2)	38.3
Patient-ExpiratoryReserveVolume(L)	0.967
Patient-FunctionalResidualCapacity(L)	1.8
Patient-InspiratoryCapacity(L)	3.45
Patient-InspiratoryReserveVolume(L)	2.84
Patient-ResidualVolume(L)	0.836
Patient-TidalVolumeBaseline(L)	0.618
Patient-TotalLungCapacity(L)	5.26
Patient-VitalCapacity(L)	4.42

Segment 3

Suction patient.

Table 5. Data request validation results for Segment 3.

Property Name	Validation	Engine Value	Percent Error	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	EqualTo 520 [17]	521.9	0.4%		VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	LessThan Segment 2 (26.64) [304] [308]	11.62		-56.4%	Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L)	LessThan Segment 2 (26.64) [304] [308]	11.63		-56.4%	Rexp

Figure 4. Vitals and ventilator monitors for Segment 3.

Table 6. Data requests for Segment 3.

Property Name	Engine Value
Patient-Height(in)	75
Patient-IdealBodyWeight(kg)	84.5
InspiratoryRespiratoryResistance(cmH2O_s/L)	11.6
ExpiratoryRespiratoryResistance(cmH2O_s/L)	11.6
RespiratoryCompliance(mL/cmH2O)	41.2
PhysiologicDeadSpaceTidalVolumeRatio	0.515
ShuntFraction	0.251
MechanicalVentilator-TidalVolume(L)	0.522
BloodPH	7.19
Aorta-Oxygen-PartialPressure(mmHg)	97.1
Aorta-CarbonDioxide-PartialPressure(mmHg)	71.1
Aorta-Bicarbonate-Molarity(mEq/L)	27.2
OxygenSaturation	0.96
HorowitzIndex(mmHg)	162
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.224
MechanicalVentilator-RespirationRate(1/min)	22.1
MechanicalVentilator-MeanAirwayPressure(cmH2O)	10.8
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	23.9
MechanicalVentilator-PlateauPressure(cmH2O)	21.1
HeartRate(1/min)	128
SystolicArterialPressure(mmHg)	110
DiastolicArterialPressure(mmHg)	82.4
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	11.5
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	11.6
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	11.6
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	40.1
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	32.8
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	46.2
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	410
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.522
MechanicalVentilator-InspiratoryExpiratoryRatio	0.225
MechanicalVentilator-InspiratoryTidalVolume(L)	0.522
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.551
MechanicalVentilator-LeakFraction	0
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.112
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	8.11
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	8
TotalPositiveEndExpiratoryPressure(cmH2O)	8.23
EndTidalCarbonDioxidePressure(mmHg)	50.2
PhysiologicDeadSpace(mL)	305
AlveolarArterialGradient(mmHg)	301
AlveolarDeadSpace(mL)	136
AnatomicDeadSpace(mL)	169
ChestWallCompliance(L/cmH2O)	0.148
FractionOfInspiredOxygen	0.599
LungCompliance(L/cmH2O)	0.0585
VentilationPerfusionRatio	2.26
HeartStrokeVolume(mL)	52.9
HeartEjectionFraction	0.433
BloodVolume(L)	7.12
MeanArterialPressure(mmHg)	96.3
PulsePressure(mmHg)	27.5
CardiacOutput(L/min)	6.75
CarbonDioxideSaturation	0.179
RespiratoryExchangeRatio	0.834
SystemicVascularResistance(mmHg_s/mL)	0.813
OxygenConsumptionRate(mL/min)	335
CarbonDioxideProductionRate(mL/min)	279
Patient-AlveoliSurfaceArea(m^2)	38.3
Patient-ExpiratoryReserveVolume(L)	0.967
Patient-FunctionalResidualCapacity(L)	1.8
Patient-InspiratoryCapacity(L)	3.45
Patient-InspiratoryReserveVolume(L)	2.84
Patient-ResidualVolume(L)	0.836
Patient-TidalVolumeBaseline(L)	0.618
Patient-TotalLungCapacity(L)	5.26
Patient-VitalCapacity(L)	4.42

Scenario Output Plots

Figure 5. Select outputs from the scenario.