Environmental

Question 1

It has been reported that approx 73% of humans with smoke inhalation injury experience respiratory failure and __% will progress to ARDS

Answer 1

20%

Question 2

What is a major contributor to the pathophysiology of smoke inhalation?

Answer 2

Inspiration of superheated particulate matter (soot)

Question 3

Why is inhalation of soot such a big deal?

Answer 3

1 - direct heat damage
2 - particles and be contaminated with toxins that get transported to the alveoli

Question 4

The major result of upper airway injury during fires?

Answer 4

Edema and inflammation leading to airway obstruction

Question 5

When does the peak of airway edema occur post fire/smoke inhalation?

Answer 5

24 hours

Question 6

During smoke inhalation, what causes the majority of lower airway injury?

Answer 6

Chemical irritation

Question 7

What is the series of events that occur after inhalation of smoke in the lower airways?

Answer 7

1 - production of neutropeptides
2 - activation of vagal nerve sensory fibers containing pro inflammatory peptides, neurokinins and calcitonin gene-related peptide
3 - severe inflammatory response
4 - sequelae include bronchconstriction, pulmonary vasoconstriction, fluid accumulation

Question 8

Name for the degenerated epithelial cells, mucus and fluid in the airways after smoke inhalation

Answer 8

Airway casts

Question 9

What is released during smoke inhalation in the lower airways that worsens VQ mismatch

Answer 9

NO

Question 10

What are the two phases of lower airway injury after smoke inhalation? When does bronchopneumonia occur? Why?

Answer 10

Hyperactive phase
Prolonged recovery phase

Pneumonia develops in the recovery phase due to disrupted bronchial epithelium and impaired innate immune system

Question 11

What are changes that occur in lung parenchyma after smoke inhalation

Answer 11

Increased fluid flux
Lack of surfactant
Loss of hypoxic pulmonary vasoconstriction (more NO)
Atelectasis
Fibrin deposition (procoagulant)

Question 12

What are systemic effects of smoke inhalation?

Answer 12

Ocular - direct corneal damage, ulceration
Cardiac - LV dysfunction (direct injury or RV hypertension)
Pulmonary - hypoxemia, hypercapnia

Question 13

What is considered a risk factor for the development of hypercoagulability on people?

Answer 13

CO inhalation

Question 14

What are the two most toxic compounds present in smoke

Answer 14

CO
HC

Question 15

What is CO’s affinity for Hb compared to oxygen?

Answer 15

200-250 x

Question 16

CO has what effect on the oxyhemoglobin dissociation curve?

Answer 16

Left (oxygen is LOCKED on, less to tissue)

Question 17

What are the “other” mechanisms of CO intracellular toxicity?

Answer 17

Inhibition of cytochrome oxidase enzyme (cells can’t use oxygen)

Inhibition of cytochrome c-oxidase (electron chain dysfunction, superoxide production, mitochondrial stress)

Question 18

Primary toxic effect of HC?

Answer 18

Inhibits electron transport chain impairing ATP production

Question 19

What neurologic syndrome occurs after smoke inhalation? When can it occur? What is the cause?

Answer 19

Delayed neurologic syndrome (DNS)
10 hours - 6 days
CO

Question 20

Hyperlactatemia in a patient with adequate perfusion parameters with a history of being in a house fire ahould raise suspicion for…

Answer 20

Carbon monoxide intoxication

Question 21

What is the half life of CO at room air

Answer 21

320 min

Question 22

What is the half life of CO at FiO2 of 1?

Answer 22

70 min

Question 23

What are considerations to make when choosing what method of oxygen to use in a smoke inhalation patient?

Answer 23

Burns on/around the nose preventing cannula placement
Excessive exudate
Upper airway obstruction (temp trach)
Neuro hypercapnia/ bad enough lower airway disease (MV)

Question 24

Other than oxygen, what is the major focus for managing smoke inhalation patients?

Answer 24

Clearing airway secretions

Question 25

Methods to clear airway secretions (smoke inhalation)

Answer 25

Early ambulation
Chest physical therapy
Airway suctioning

Question 26

What are aerosolized medications that can be used for smoke inhalation patients? List each’s benefit

Answer 26

Albuterol - bronchodilation, anti-inflammatory, promote alveolar fluid clearance

Epinephrine - bronchodilator, vasoconstriction, break up secretions

NAC - mucolytic (BUT can cause bronchconstriction)

Heparin - reduce airway fibrin casts, paper showed reduced mortality with use

Question 27

A recent meta-analysis of human patients with inhalation injury concluded that what nebulized drug was associated with reduced mortality, improved lung function, and shortened the period of MV?

Answer 27

Nebulized heparin

Question 28

What are the antidotes for HC toxicity? Which is safer and why?

Answer 28

Amyl nitrate and sodium thiosulfate
Hydroxycobalamin

Hydroxycobalamin because it binds cyanide to form cyanocobalamin (not methemoglobinemia)