ARDS & Oxygenation

Question 1

What does ARDS stand for?

Answer 1

Acute respiratory distress syndrome

Question 2

Definition of ARDS?

Answer 2

Respiratory failure second to pulmonary or systemic insult without evidence of heart failure

Question 3

Onset of ARDS?

Answer 3

Generally 12-48hrs but up to 1 wk of trigger

Question 4

Causes of ARDS?

Answer 4

MC: Sepsis, aspiration/inhalation of harmful substances, burns, trauma, pneumonia, intubation
Other: OD, high altitude sickness, multiple transfusions, DIC, pancreatitis

Question 5

Pathophys of ARDS?

Answer 5

Damage to capillary and alveolar endothelial cells d/t increased vascular permeability and diminished surfactant —> pulmonary edema & alveolar collapse causing hypoxemia

Question 6

Characteristics of ARDS?

Answer 6

Rapid onset dyspnea (tachypnea, retractions), crackles, abnormal CXR, hypoxemia refractory to O2, shock can develop

Question 7

CXR for ARDS?

Answer 7

Diffuse bilateral patchy infiltrates (air bronchograms)

-venus congestion, cardiomegaly, pleural effusion uncommon

Question 8

Treatment for ARDS?

Answer 8

aggressive dx & tx of underlying disorder, usually intubation needed/adjustments to ventilator to avoid O2 toxicities
-supportive tx: fluids, fever control

Question 9

Are there any preventative measures for ARDS?

Answer 9

None identified

Question 10

Is steroid therapy effective for ARDS?

Answer 10

Not proven

Question 11

Mortality rate of ARDS?

Answer 11

30-40% (90% if secondary to sepsis)

Question 12

If ARDS patients survive, they will have some degree of _______ _________

Answer 12

chronic symptoms

Question 13

What is a cricothyrotomy?

Answer 13

Emergency surgical airway (incision made between thyroid cartilage and cricoid cartilage)

Question 14

Indications for a cricothyrotomy?

Answer 14

Unable to intubate or maintain oxygenation w/ bagging, severe facial trauma

Question 15

Relative C/I of cricothyrotomy?

Answer 15

<12 y/o, obliteration of landmarks, coagulopathy

Question 16

Alternative to cricothyrotomy?

Answer 16

Needle cricothyrotomy w/ transtracheal jet ventilation

Question 17

Indications for needle cricothyrotomy w/ transtracheal jet ventilation?

Answer 17

Acceptable in peds, safer in coagulopathy

Question 18

Does needle cricothyrotomy w/ transtracheal jet ventilation protect the airway?

Answer 18

No

Question 19

What does needle cricothyrotomy w/ transtracheal jet ventilation require?

Answer 19

Clear upper airway passages and oral/nasal airway devices

Question 20

Procedure diagram

Question 21

What is the importance of pre-oxygenation?

Answer 21

Extends the duration of safe apnea

Question 22

What is safe apnea defined as?

Answer 22

The time until a patient reaches a saturation level of 88% to 90%

Question 23

Process of pre-oxygenation?

Answer 23

De-nitrogenating residual capacity of the lungs to maximize O2 storage w/in the lungs

Question 24

In a patient breathing room air before rapid sequence tracheal intubation (PaO2 90-100) desaturation will occur in how long between sedative/paralytic administration and airway placement (and how it can change with pre-oxygenation)?

Answer 24

in the 45-60 seconds between the two
*3 min HIGH FLOW O2 (NC+NRB) WILL INC TIME UP TO 8 min

Question 25

Positioning of the patient for pre-oxygenation in order to maximize upper airway dimensions/promote airway patency?

Answer 25

Position pt w/ external auditory meatus on same horizontal plane as sternal notch (20 degrees from horizontal), or reverse trendelenburg

Question 26

OOPS mnemonic of failed intubation desaturation?

Answer 26

Oxygen, On, Pull mandible forward, Sit patient up

Question 27

What is a bad combination for ventilation and oxygenation?

Answer 27

Combining loss of tone with recumbency, oral obstruction by tongue, alveolar collapse

Question 28

What are the four phases of a mechanical breath?

Answer 28

Triggering, Inspiration, Cycling, Expiration

Question 29

What is triggering (phase of mechanical breath)?

Answer 29

Transitioning from expiration to inspiration caused by elapsed time or patient initiation

Question 30

What is inspiration (phase of mechanical breath)?

Answer 30

Flow of gas from ventilator to patient (set for specific volume of pressure)

Question 31

What is cycling (phase of mechanical breath)?

Answer 31

Transitioning from inspiration to expiration d/t decreased flow, elapsed time, or delivered volume

Question 32

What is expiration (phase of mechanical breath)?

Answer 32

Ventilator flow stops & gas passively flows out of lungs

Question 33

Where is the volume control/assist control (VC/AC) ventilator mode most commonly used?

Answer 33

ED

Question 34

Volume control settings in VC/AC ventilator mode?

Answer 34

Target tidal volume 6-8mL/kg, and respiratory rate 10-14 breaths/min are set

Question 35

Assist control settings in VC/AC ventilator mode?

Answer 35

Patient effort triggers breath (delivered at set volume or pressure), a breath will be automatically delivered if not initiated by the patient within a set time

Question 36

Advantages of VC/AC ventilator mode?

Answer 36

Dec work of breathing, guaranteed minute ventilation

Question 37

Disadvantages of VC/AC ventilator mode?

Answer 37

May lead to excessive inspiratory pressures

Question 38

Other ventilator modes (other than VC/AC)?

Answer 38

PC/AC (pressure control/assist control), SIMV (synchronized intermittent mandatory ventilation), PSV (pressure support ventilation)

Question 39

PEEP! watch lecture !

Question 40

What can ARDS be secondary to (oxygenation wise)?

Answer 40

High tidal volumes from oxygenation

Question 41

How to prevent ARDS secondary to oxygenation?

Answer 41

-Use low tidal volumes (6mL/kg) and limited distending pressures
*tidal volume set according to predicted body weight based on height

-Increase PEEP & place in prone position once ARDS begins
*higher PEEP in pts w/ obesity or ascites