acute respiratory failure and basic ventilator … 2020/day...identify acute respiratory distress...

Acute Respiratory Failure and

Basic Ventilator ManagementHeather A. Wallace, MSc., MPAS. PA-C

LT, MSC, USN

Describe anatomy and physiology of the respiratory system

Identify causes of acute respiratory failure

Identify acute respiratory distress syndrome (ARDS)

Describe strategies for the treatment of acute respiratory distress syndrome (ARDS)

List some adjunct rescue modalities for severe refractory hypoxemia

Evaluate an arterial blood gas

Identify initial approach to mechanical ventilation

44 yo F

PMH: HTN, DM2, PCOS

CC: sore throat, fever, cough x 3 days, and SOB x 2 days

Presentation: Peripheral cyanosis, tachypneic

VS: 101.1F, 90/60, HR 125, RR 42, Sat 54%

(+) for Influenza A

44 yo F, + Flu A PCR

You now decide to:

1. Write rx for Tamiflu, antipyretic, and analgesic

2. Order a CBC, Chemistry panel, UA

3. Write her a sick note for 3 days

4. Order a CXR

Controller(CNS)

Wiring (PNS)Bellows

(Thoracic cavity)

Airway Lungs/Alveoli

One way of viewing respiratory physiology is by function and structural components

Intrapulmonary airways3

Lungs/Alveoli

44 yo F

PMH: HTN, DM2, PCOS

CC: sore throat, fever, cough x 3 days, and SOB x 2 days

Presentation: Peripheral cyanosis, tachypneic

VS: 101.1F, 90/60, HR 125, RR 42, O2Sat 54%

(+) for Influenza A


You now decide to:

1. Obtain a CT of her chest

2. Give her a fluid bolus

3. Plan for RSI and mechanical ventilation

4. Start high flow nasal cannula

Diffuse alveolar flooding

Increased right-to-left shunt across the lungs (more alveoli

with V/Q =0)

Decrease in PaO2Resistance to O2 therapy

Hypoxemic respiratory failure

Increased V/Q mismatch (more alveoli with V/Q << 1)

Lungs/Alveoli


You now decide to:

1. Obtain a CT of her chest

2. Give her a fluid bolus

3. Plan for RSI and mechanical ventilation

4. Start high flow nasal cannula

44 yo F, + Flu A PCR (PBW=60kg)

You set her initial vent settings to:

1.AC mode, RR 20, Vt=520cc, FIO2 100%, PEEP 5cm H2O

2. AC mode, RR 12, Vt=360cc, FIO2 100%, PEEP 12cm H2O

3. Pressure Support mode, RR 20, Vt=520cc, FIO2 100%, PEEP 5cm H2O


Mechanical ventilator breathsVolume (flow controlled or time cycled)Pressure control (pressure controlled, time cycled)Pressure support (pressure controlled, flow cycled)

Forces during Inspiration and Expiration 3Pressure-Time Curve During Volume Control Ventilation 18,

Characteristic pressure-flow waveforms for spontaneous breathing and ventilated breaths 4,

Modes - combination of breaths to create ventilation strategy

Continuous mandatory ventilation (CMV)

With all volume or all pressure controlled breaths

Assist control ventilationWith all volume or all pressure controlled breaths

Stand-alone pressure support ventilation (PSV)Synchronized intermittent mandatory ventilation (SIMV)

Volume or pressure control basal or back up breaths synchronized to patient effort plus humidified gas for additional spontaneous breathing

Overview of Selected Modes of Ventilation4

SettingsTidal volume (VT) Respiratory rate (RR) Positive end-expiratory pressure (PEEP)Fraction of inspired oxygen (FiO2)Flow rate

Understanding lung protection17

ARDSNet Mechanical Ventilation Protocol 12

44 yo F with ARDS, + Flu A PCR (PBW=60kg)

You set her initial vent settings to:

1.AC mode, RR 20, Vt=520cc, FIO2 100%, PEEP 5cm H2O

2. AC mode, RR 12, Vt=360cc, FIO2 100%, PEEP 12cm H2O



Uncompensated Acid-Base

DisturbancespH PCO2 (mmHg) HCO3- (mEq/L) Common Cause

None (normal value)

Respiratory acidosis

Respiratory alkalosis

Metabolic acidosis

Metabolic alkalosis


Intubated and mechanical ventilation initiated

CXR demonstrated b/l alveolar infiltrates

IBW 60kg

6 hours later:

VS: 99F, 120/75, HR 105, RR 30, Sat 92%

On AC 18 breaths per min

FIO2 80%, PEEP 12cm H2O

Vt = 360cc

Ppeak = 35, Pplat =32cm H2O

ABG = 7.37 /38 /64 /92%

Timing - Acute. Within 72 hours of a recognized risk factor or within 7 days.

Chest imaging - Bilateral opacities consistent with pulmonary edema are seen of chest radiograph or chest CT scan.

Origin of pulmonary edema - Respiratory failure not fully explained by cardiac failures or volume overload.

Hypoxemia

Mild ARDS: 200 < PaO2/FIO2 </= 300 with PEEP or CPAP >/= 5cmH2O

Moderate ARDS: 100 < PaO2/FIO2 < /= 200 with PEEP or CPAP > /= 5cmH2O

Severe ARDS: PaO2/FIO2 < /= 100 with PEEP 5cmH2O

Risk Factors: Sepsis, SIRS, shock, Trauma, acid aspiration, near-drowning, multiple emergency blood product transfusions, pancreatitis, DIC, burn




IBW 60kg

6 hours later:

VS: 99F, 120/75, HR 105, RR 30, Sat 92%

On AC 18 breaths per min

FIO2 80%, PEEP 12cm H2O

Vt = 360cc

Ppeak = 35, Pplat =32cm H2O

ABG = 7.37 /38 /64 /92%

ABGs

Oxygenation

FiO2

PEEP

Ventilation

RR

44 yo F with ARDS, + Flu A PCR

You now decide to:

1. Decrease Vt to 300cc

2. Increase PEEP to 15cm H2O

3. Add Inhaled NO

4. Initiate prone ventilation


The best evidence now suggests you:

1. Administer cis-atracurium

2. Institute ECMO

3. Start HFOV (high frequency oscillatory ventilation

4. Prone position the patient

Prone Position Ventilation

Neuromuscular Blockade (NMB)

High Frequency Oscillatory Ventilation (HFOV)

Extracorporeal membrane oxygenation

Inhaled Nitric Oxide (iNO)


The best evidence now suggests you:

1. Administer cis-atracurium

2. Institute ECMO

3. Start HFOV (high frequency oscillatory ventilation

4. Prone position the patient




IBW 60kg

10 hours later:

She is still on the vent. Failing to wean. Has proximal myopathy w/ strength 2-3/5 in most muscle groups.

Failed 40% 5/5 SBT two days in a row after 25 minutes. RR 30

FIO2 40%, PEEP 5 cm H2O

Vt = 200cc

RSBI =115


You know decide to:

1. Continue to optimize medical management and attempt SBT daily in advance of liberation

2. Proceed with a tracheostomy and daily face mask trials

3. Proceed with a tracheostomy and PSV/CPAP 5/5 trials

4. Extubate to high flow nasal cannula

Awakening

Breathing

Coordination

Delirium

Early Mobility

Family Engagement

Classification of Acute Respiratory Failure 9

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6. Neurosciences - ABPN Neurology Boards: Neural Control of Respiration. Draw It to Know It. http://www.drawittoknowit.com/course/neurosciences-abpn-boards/autonomics/specialized-circuitry/1307/neural-control-of-respiration. Accessed December 26, 2019.

7. Aminoff MJ, Josephson SA, eds. Aminoff’s Neurology and General Medicine. 5 edition. Amesterdam: Academic Press; 2014.

8. Physiology: Overview of Airway Physiology. Draw It to Know It. http://www.drawittoknowit.com/course/physiology/respiratory/overview/1282/overview-of-respiratory-structures-and-functions. Accessed December 28, 2019.

9. Fink MD MP. Textbook of Critical Care. 7 edition. (Vincent MD PhD J-L, MCCM FA, eds.). Philadelphia, PA: Elsevier; 2017.

10. The Acute Respiratory Distress Syndrome Network. Ventilation with Lower Tidal Volumes as Compared with Traditional Tidal Volumes for Acute Lung Injury and the Acute Respiratory Distress Syndrome. N Engl J Med. 2000;342:1301-1308. doi:DOI: 10.1056/NEJM200005043421801

11. The National Heart, Lung, and Blood Institute ARDS Clinical Trials Network. Higher versus Lower Positive End-Expiratory Pressures in Patients with the Acute Respiratory Distress Syndrome. N Engl J Med. 351:327-336. doi:DOI: 10.1056/NEJMoa032193

12. NIH NHLBI ARDS Clinical Network Mechanical Ventilation Protocol Summary. http://www.ardsnet.org/files/ventilator_protocol_2008-07.pdf. Accessed January 20, 2020.

13. Assessment of Low tidal Volume and elevated End-expiratory volume to Obviate Lung Injury (ALVEOLI). http://www.ardsnet.org/files/alveoliV1_1999-07-20.pdf. Accessed January 20, 2020.

14. Hager DN, Krishnan JA, Hayden DL, Brower RG. Tidal Volume Reduction in Patients with Acute Lung Injury When Plateau Pressures Are Not High. Am J Respir Crit Care Med. 2005;172(10):1241-1245. doi:10.1164/rccm.200501-048CP

15. Amato MBP, Meade MO, Slutsky AS, et al. Driving Pressure and Survival in the Acute Respiratory Distress Syndrome. N Engl J Med. 2015;372(8):747-755. doi:10.1056/NEJMsa1410639

16. Villar J, Martín-Rodríguez C, Domínguez-Berrot AM, et al. A Quantile Analysis of Plateau and Driving Pressures: Effects on Mortality in Patients With Acute Respiratory Distress Syndrome Receiving Lung-Protective Ventilation*. Crit Care Med. 2017;45(5):843. doi:10.1097/CCM.0000000000002330

17. Hubmayr RD, Pannu S. Understanding lung protection. Intensive Care Med. 2015;41(12):2184-2186. doi:10.1007/s00134-015-4100-y

18. Alviar CL, Miller PE, McAreavey D, et al. Positive Pressure Ventilation in the Cardiac Intensive Care Unit. J Am Coll Cardiol. 2018;72(13):1532-1553. doi:10.1016/j.jacc.2018.06.074

19. Young D, Harrison DA, Cuthbertson BH, Rowan K, Collaborators for the T. Effect of Early vs Late Tracheostomy Placement on Survival in Patients Receiving Mechanical Ventilation: The TracMan Randomized Trial. JAMA. 2013;309(20):2121-2129. doi:10.1001/jama.2013.5154

20. Jubran A, Grant BJB, Duffner LA, et al. Effect of Pressure Support vs Unassisted Breathing Through a Tracheostomy Collar on Weaning Duration in Patients Requiring Prolonged Mechanical Ventilation: A Randomized Trial. JAMA. 2013;309(7):671-677. doi:10.1001/jama.2013.159

21. Papazian L, Forel J-M, Gacouin A, et al. Neuromuscular Blockers in Early Acute Respiratory Distress Syndrome. N Engl J Med. 2010;363(12):1107-1116. doi:10.1056/NEJMoa1005372

22. Early Neuromuscular Blockade in the Acute Respiratory Distress Syndrome. N Engl J Med. 2019;380(21):1997-2008. doi:10.1056/NEJMoa1901686

23. Guérin C, Reignier J, Richard J-C, et al. Prone Positioning in Severe Acute Respiratory Distress Syndrome. N Engl J Med. 2013;368(23):2159-2168. doi:10.1056/NEJMoa1214103

24. Ferguson ND, Cook DJ, Guyatt GH, et al. High-Frequency Oscillation in Early Acute Respiratory Distress Syndrome. N Engl J Med. 2013;368(9):795-805. doi:10.1056/NEJMoa1215554

25. Combes A, Hajage D, Capellier G, et al. Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome. N Engl J Med. 2018;378(21):1965-1975. doi:10.1056/NEJMoa1800385

26. Thompson BT, Chambers RC, Liu KD. Acute Respiratory Distress Syndrome. N Engl J Med. 2017;377(6):562-572. doi:10.1056/NEJMra1608077

Thank you

–Johnny Appleseed

“Type a quote here”

I have no financial interests to disclose with regard to this subject or the contents of the presentation.

Decrease in respiratory drive from CNS

Decrease in respiratory rate and tidal volume

Decrease in minute ventilation

Decrease in alveolar ventilation Loss of normal response to elevated PaCO2

PaCO2 increases pH and PaO2 decrease

Controller(CNS)

Decrease in respiratory muscle strength

Decrease in respiratory rate and tidal volume

Decrease in minute ventilation and alveolar ventilation

Loss of spontaneous sigh

Inactivation of surfactantUnstable alveoli

PaCO2 increases

pH and PaO2 decrease

MicroatelectasisDecrease in compliance

Increased [PAO2 -PaO2]

Bellows(Thoracic

cavity)

Airway obstruction

Decreased FEV1

Decrease in maximal voluntary ventilation

Decrease in maximal sustainable ventilation

Decreased ventilatory capacity (20L/min)

HyperinflationFlattened diaphragms

Airway

Increased work of breathing

(VCO2)

Increased VD/VT

Hyperventilation (early phase of

asthma)

Example: VCO2 rises from 200mL/min to 300mL/min

Example: VD/VT increases from 0.3 to 0.6

Example: PaCO2 falls from 40mmHg to 30mmHg

Increased ventilatory demand(VE increases from 7.1 L/min to 25

L/min)

Which of the following interventions has been associated with improved mortality in clinical trials of patients with ARDS?

1.Ventilation with low tidal volumes (6ml/kg of predicted body weight)

2.Ventilation with high PEEP (>10cm H2O)

3.Ventilation with inspiratory-to-expiratory ratio (I:E ratio) greater than 2:1

4.High-frequency oscillatory ventilation (HFOV)

Which of the following patients is most likely to have a mortality benefit from ventilation in the prone position?

1.A 54-year-old female with severe cardiogenic pulmonary edema supported by mechanical ventilation requiring high FIO2

2.A 45-year-old male with multifocal pneumonia and ARDS supported by mechanical ventilation (FIO2 0.7, PEEP 10, PaO2/FIO2 90)

3.A 35-year-old female with ARDS post-aspiration pneumonia supported by mechanical ventilation (FIO2 1.0, PEEP 5, PaO2/FIO2 250)

4.A 76-year-old male with severe influenza and ARDS supported by mechanical ventilation (FIO2 0.8, PEEP 12, PaO2/FIO2 180)

6

12

3

54

9 10

78

1

87

910

65

2

34

Segments of the pulmonary lobes. RLL, Right lower lobe. 1. Named branches of the tracheobronchial tree, viewed from the front 2

Intrapulmonary airways and circulation 3

Control of respiration 4

Controller(CNS) Wiring (PNS)

Bellows(Thoracic

cavity)Airway Lungs/Alveoli

Functional and structural components of respiration

Neural Control of Respiration6

Controller(CNS)

Ventral respiratory group (VRG)- Nucleus ambiguous (CN XI,

X)- Botzinger complex- Pre-Botzinger complex

(pacemaker cells - opioid sensitive)

Dorsal respiratory group (DRG)- Solitary tract

nucleus (CN IX, X)

Pneumotaxic center(medial parabrachial nucleus, Kolliker-fuse nucleus)

Apneustic center (diffuse lower pontine nucleus)

Phrenic motor neuronsC3,C4,C5 “keep the diaphragm alive…”

ANTERIOR POSTERIOR

The Respiratory System and PNS 7

Wiring (PNS)

Bellows(Thoracic

cavity)

Forces during Inspiration and Expiration 3

Airways8

Airway

Intrapulmonary airways3

Lungs/Alveoli

acute respiratory failure and basic ventilator … 2020/day...identify acute respiratory distress...

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