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 C, 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.After intubation he is on mechanical ventilation and remains sedated with a RASS of -2.

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

Learning Objectives:

Assess baseline status
Recognize moderate ARDS

Recommended Actions:

None

Ventilator settings are:

Mode	VT (L)	PIP (cmH2O)	Flow (L/min)	I:E	TI (s)	RR (bpm)	PEEP (cmH2O)	FiO2
PC-CMV	NA	20	NA	NA	0.6	10	10	0.60

Table 1. Data request validation results for Segment 1.

Property Name	Validation	Engine Value	Percent Error	Notes
InspiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	12.4	3.08%	Rinsp for moderate ARDS
ExpiratoryRespiratoryResistance(cmH2O_s/L)	EqualTo 12 [17]	12.4	3.08%	Rexp for moderate ARDS
RespiratoryCompliance(mL/cmH2O)	EqualTo 40 [305]	42.7	6.45%	C requested by SME for moderate ARDS
PhysiologicDeadSpaceTidalVolumeRatio	EqualTo 0.57 [230]	0.553	3.03%	VD/VT for moderate ARDS
ClinicalShuntFraction	[0.300,0.500] [222]	0.285	5.14%	QS/QT for moderate ARDS (determined from blood gas values)
HorowitzIndex(mmHg)	[100,200] [115]	120	0.00%	PaO2/FiO2 for moderate ARDS

Figure 2. Vitals and ventilator monitors for Segment 1.

Table 2. Data requests for Segment 1.

Property Name	Engine Value
Patient-Height(in)	75.0
Patient-IdealBodyWeight(kg)	84.5
InspiratoryRespiratoryResistance(cmH2O_s/L)	12.4
ExpiratoryRespiratoryResistance(cmH2O_s/L)	12.4
RespiratoryCompliance(mL/cmH2O)	42.7
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.596
ClinicalShuntFraction	0.285
MechanicalVentilator-TidalVolume(L)	0.413
BloodPH	7.28
Aorta-Oxygen-PartialPressure(mmHg)	72.0
Aorta-CarbonDioxide-PartialPressure(mmHg)	55.9
Aorta-Bicarbonate-Molarity(mEq/L)	26.6
OxygenSaturation	0.933
HorowitzIndex(mmHg)	120
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0608
MechanicalVentilator-RespirationRate(1/min)	34.5
MechanicalVentilator-MeanAirwayPressure(cmH2O)	13.3
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	20.0
MechanicalVentilator-PlateauPressure(cmH2O)	20.8
HeartRate(1/min)	71.4
SystolicArterialPressure(mmHg)	115
DiastolicArterialPressure(mmHg)	73.5
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	14.2
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	42.4
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	41.4
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	33.9
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	423
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.413
MechanicalVentilator-InspiratoryExpiratoryRatio	0.526
MechanicalVentilator-InspiratoryTidalVolume(L)	0.413
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.674
MechanicalVentilator-LeakFraction	4.63e-06
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.11
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	11.1
PhysiologicDeadSpaceTidalVolumeRatio	0.553
PhysiologicShuntFraction	0.288
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelCompliance(mL/cmH2O)	48.0
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10.0
TotalPositiveEndExpiratoryPressure(cmH2O)	10.1
EndTidalCarbonDioxidePressure(mmHg)	38.3
PhysiologicDeadSpace(mL)	327
AlveolarArterialGradient(mmHg)	336
AlveolarDeadSpace(mL)	158
AnatomicDeadSpace(mL)	169
ChestWallCompliance(L/cmH2O)	0.237
FractionOfInspiredOxygen	0.599
LungCompliance(L/cmH2O)	0.0590
VentilationPerfusionRatio	2.44
HeartStrokeVolume(mL)	83.5
HeartEjectionFraction	0.560
BloodVolume(L)	7.08
MeanArterialPressure(mmHg)	95.4
PulsePressure(mmHg)	41.1
CardiacOutput(L/min)	5.96
CarbonDioxideSaturation	0.465
RespiratoryExchangeRatio	0.818
SystemicVascularResistance(mmHg_s/mL)	0.911
OxygenConsumptionRate(mL/min)	311
CarbonDioxideProductionRate(mL/min)	255
Patient-AlveoliSurfaceArea(m^2)	15.3
Patient-ExpiratoryReserveVolume(L)	0.969
Patient-FunctionalResidualCapacity(L)	1.43
Patient-InspiratoryCapacity(L)	3.46
Patient-InspiratoryReserveVolume(L)	2.84
Patient-ResidualVolume(L)	0.457
Patient-TidalVolumeBaseline(L)	0.622
Patient-TotalLungCapacity(L)	4.89
Patient-VitalCapacity(L)	4.43

Segment 2

The patient is loaded onto the aircraft for transfer to Level III care. During transport the patient becomes agitated and respiratory rate increases and SpO2 has fallen. Learning Objectives:

Recognize hypoventilation due to increased secretions
Recognize gas trapping due to high respiratory rate (expiratory flow does not return to zero)

Recommended Actions:

Check for pneumothorax
Suction

Table 3. Data request validation results for Segment 2.

Property Name	Validation	Engine Value	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	LessThan Segment1 (413)	203	-50.8%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment1 (12.4) [305] [309]	20.5	65.8%	Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L)	GreaterThan Segment1 (12.4) [305] [309]	20.5	65.8%	Rexp

Figure 3. Vitals and ventilator monitors for Segment 2.

Table 4. Data requests for Segment 2.

Property Name	Engine Value
Patient-Height(in)	75.0
Patient-IdealBodyWeight(kg)	84.5
InspiratoryRespiratoryResistance(cmH2O_s/L)	20.5
ExpiratoryRespiratoryResistance(cmH2O_s/L)	20.5
RespiratoryCompliance(mL/cmH2O)	43.6
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.569
ClinicalShuntFraction	0.273
MechanicalVentilator-TidalVolume(L)	0.203
BloodPH	7.19
Aorta-Oxygen-PartialPressure(mmHg)	79.4
Aorta-CarbonDioxide-PartialPressure(mmHg)	70.0
Aorta-Bicarbonate-Molarity(mEq/L)	27.2
OxygenSaturation	0.934
HorowitzIndex(mmHg)	137
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.404
MechanicalVentilator-RespirationRate(1/min)	45.5
MechanicalVentilator-MeanAirwayPressure(cmH2O)	14.4
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	20.0
MechanicalVentilator-PlateauPressure(cmH2O)	16.8
HeartRate(1/min)	119
SystolicArterialPressure(mmHg)	110
DiastolicArterialPressure(mmHg)	81.9
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	9.23
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	20.5
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	20.5
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	43.4
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	20.3
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	35.6
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	409
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.203
MechanicalVentilator-InspiratoryExpiratoryRatio	0.833
MechanicalVentilator-InspiratoryTidalVolume(L)	0.203
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.460
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	2.09
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	12.1
PhysiologicDeadSpaceTidalVolumeRatio	0.553
PhysiologicShuntFraction	0.276
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	20.5
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	20.5
TotalRespiratoryModelCompliance(mL/cmH2O)	47.9
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10.0
TotalPositiveEndExpiratoryPressure(cmH2O)	10.4
EndTidalCarbonDioxidePressure(mmHg)	43.7
PhysiologicDeadSpace(mL)	327
AlveolarArterialGradient(mmHg)	289
AlveolarDeadSpace(mL)	158
AnatomicDeadSpace(mL)	169
ChestWallCompliance(L/cmH2O)	0.176
FractionOfInspiredOxygen	0.579
LungCompliance(L/cmH2O)	0.0589
VentilationPerfusionRatio	1.45
HeartStrokeVolume(mL)	55.5
HeartEjectionFraction	0.449
BloodVolume(L)	7.10
MeanArterialPressure(mmHg)	96.3
PulsePressure(mmHg)	28.4
CardiacOutput(L/min)	6.63
CarbonDioxideSaturation	0.608
RespiratoryExchangeRatio	0.827
SystemicVascularResistance(mmHg_s/mL)	0.827
OxygenConsumptionRate(mL/min)	323
CarbonDioxideProductionRate(mL/min)	267
Patient-AlveoliSurfaceArea(m^2)	15.3
Patient-ExpiratoryReserveVolume(L)	0.969
Patient-FunctionalResidualCapacity(L)	1.43
Patient-InspiratoryCapacity(L)	3.46
Patient-InspiratoryReserveVolume(L)	2.84
Patient-ResidualVolume(L)	0.457
Patient-TidalVolumeBaseline(L)	0.622
Patient-TotalLungCapacity(L)	4.89
Patient-VitalCapacity(L)	4.43

Segment 3

Patient is suctioned for large volume of thick secretions. Learning Objectives:

Recognize that suctioning decreased airway resistance and restored tidal volume)

Recommended Actions:

None

Table 5. Data request validation results for Segment 3.

Property Name	Validation	Engine Value	Percent Change	Notes
MechanicalVentilator-TidalVolume(mL)	GreaterThan Segment2 (203)	416	105%	VT (measured)
InspiratoryRespiratoryResistance(cmH2O_s/L)	LessThan Segment2 (20.5) [305] [309]	12.4	-39.7%	Rinsp
ExpiratoryRespiratoryResistance(cmH2O_s/L)	LessThan Segment2 (20.5) [305] [309]	12.4	-39.7%	Rexp

Figure 4. Vitals and ventilator monitors for Segment 3.

Table 6. Data requests for Segment 3.

Property Name	Engine Value
Patient-Height(in)	75.0
Patient-IdealBodyWeight(kg)	84.5
InspiratoryRespiratoryResistance(cmH2O_s/L)	12.4
ExpiratoryRespiratoryResistance(cmH2O_s/L)	12.4
RespiratoryCompliance(mL/cmH2O)	43.0
ClinicalPhysiologicDeadSpaceTidalVolumeRatio	0.599
ClinicalShuntFraction	0.283
MechanicalVentilator-TidalVolume(L)	0.416
BloodPH	7.27
Aorta-Oxygen-PartialPressure(mmHg)	73.5
Aorta-CarbonDioxide-PartialPressure(mmHg)	57.9
Aorta-Bicarbonate-Molarity(mEq/L)	26.7
OxygenSaturation	0.933
HorowitzIndex(mmHg)	123
IntrinsicPositiveEndExpiratoryPressure(cmH2O)	0.0937
MechanicalVentilator-RespirationRate(1/min)	34.9
MechanicalVentilator-MeanAirwayPressure(cmH2O)	13.3
MechanicalVentilator-PeakInspiratoryPressure(cmH2O)	20.0
MechanicalVentilator-PlateauPressure(cmH2O)	20.9
HeartRate(1/min)	70.5
SystolicArterialPressure(mmHg)	115
DiastolicArterialPressure(mmHg)	73.0
MechanicalVentilator-TotalPulmonaryVentilation(L/min)	14.4
MechanicalVentilator-InspiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-ExpiratoryResistance(cmH2O_s/L)	12.4
MechanicalVentilator-StaticRespiratoryCompliance(mL/cmH2O)	42.6
MechanicalVentilator-DynamicRespiratoryCompliance(mL/cmH2O)	41.6
MechanicalVentilator-EndTidalCarbonDioxidePressure(mmHg)	35.1
MechanicalVentilator-EndTidalOxygenPressure(mmHg)	423
MechanicalVentilator-ExpiratoryTidalVolume(L)	0.417
MechanicalVentilator-InspiratoryExpiratoryRatio	0.536
MechanicalVentilator-InspiratoryTidalVolume(L)	0.416
MechanicalVentilator-PeakExpiratoryFlow(L/s)	0.693
MechanicalVentilator-LeakFraction	0.00
MechanicalVentilator-IntrinsicPositiveEndExpiratoryPressure(cmH2O)	1.16
MechanicalVentilator-ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10.0
MechanicalVentilator-TotalPositiveEndExpiratoryPressure(cmH2O)	11.2
PhysiologicDeadSpaceTidalVolumeRatio	0.553
PhysiologicShuntFraction	0.286
TotalRespiratoryModelInspiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelExpiratoryResistance(cmH2O_s/L)	12.4
TotalRespiratoryModelCompliance(mL/cmH2O)	46.4
ExtrinsicPositiveEndExpiratoryPressure(cmH2O)	10.0
TotalPositiveEndExpiratoryPressure(cmH2O)	10.1
EndTidalCarbonDioxidePressure(mmHg)	39.5
PhysiologicDeadSpace(mL)	327
AlveolarArterialGradient(mmHg)	331
AlveolarDeadSpace(mL)	158
AnatomicDeadSpace(mL)	169
ChestWallCompliance(L/cmH2O)	0.188
FractionOfInspiredOxygen	0.599
LungCompliance(L/cmH2O)	0.0591
VentilationPerfusionRatio	2.46
HeartStrokeVolume(mL)	86.1
HeartEjectionFraction	0.566
BloodVolume(L)	7.15
MeanArterialPressure(mmHg)	95.5
PulsePressure(mmHg)	42.4
CardiacOutput(L/min)	6.07
CarbonDioxideSaturation	0.493
RespiratoryExchangeRatio	0.821
SystemicVascularResistance(mmHg_s/mL)	0.896
OxygenConsumptionRate(mL/min)	314
CarbonDioxideProductionRate(mL/min)	258
Patient-AlveoliSurfaceArea(m^2)	15.3
Patient-ExpiratoryReserveVolume(L)	0.969
Patient-FunctionalResidualCapacity(L)	1.43
Patient-InspiratoryCapacity(L)	3.46
Patient-InspiratoryReserveVolume(L)	2.84
Patient-ResidualVolume(L)	0.457
Patient-TidalVolumeBaseline(L)	0.622
Patient-TotalLungCapacity(L)	4.89
Patient-VitalCapacity(L)	4.43

Scenario Output Plots

Figure 5. Select outputs from the scenario.