Lecture 9b - Acute Trauma: ARDS - acute respiratory distress syndrome

Question 1

What changes occur as a result of #rib or flail segment

Answer 1

• pain
• decreased movement of ribs
• decreased gas mvmnt = decreased paO2
• decreased gas mvmnt = increase paCO2 - increased -load, decreased pump efficiency
• decreased secretion movement - decrease cough effectiveness, decreased lung vols = decreased EFR

Question 2

What are some examples of blunt trauma to the lungs/rib cage

Answer 2

rib #
flail segment
sternal fracture
pulmonary contusion - bruising of lung

Question 3

What are the effects of a pulmonary contusion

Answer 3

activation of coagulation cascade

• impaired lung function
• decreased co2 movement - decrease in Cl, incr resp load
• decrease 02 movement - decreased SA

Question 4

Physio managment for rib#, pulmonary contusion

Answer 4

pain management
- if intubated - MHI for gas, Suction for secretion
- if spontaneously breathing - DBE for gas, huff/cough
positioning
mobs

Question 5

What is the definition of ARDS/Acute lung injury (ALI)

Answer 5

clinical syndrome characterized by non-cardiogenic pulmonary edema with bilateral disuse alveolar damage

results from endothelial injury/inflammation and increased microvascular permeability

Question 6

What are the characteristics of ARDS

Answer 6

acute hypoxaemic resp failure (within a week)
new bilateral diffuse infiltrates on CXR consistent with pulmonary edema
no clinical evidence of heart failure, fluid overload, or chronic lung disease

Question 7

what is the BERLIN definition criteria for ARDS

Answer 7

Mild - 200-300mmHg paO2/Fio2
Moderate: 100-200
Severe: <100

Question 8

What are the causes of ARDS (direct lung insult)

Answer 8

pneumonia 
aspiration of gastric contents
lung contusion
near drowning 
inhalation of toxic gas
fat embolus

Question 9

What are the causes of ARDS (indirect lung insult)

Answer 9

sepsis 
non thoracic trauma 
multiple transfusions 
pancreatitis 
cardiopulmonary bypass
severe burns
drug overdose

Question 10

ARDS pathogenesis 3 phases? and key features

Answer 10

1) Exudative phase - fluid accumulation - damage to alveolar capillary barrier (leaky), inflammatory infiltrates, surfactant dysfunction
2) Proliferative phase - thickening of endo,epithelium and insterstitial space
Fibrotic Phase - interstitial fibrosis, vascular occlusion

Question 11

ARDS pathophysiology for o2 and co2 movement

Answer 11

o2 - decrease SA - caused by fluid filled alveoli and perfusion of non-ventilated alveoli, pulmonary vasoconstriction/microvascular occlusion

co2- increased resp load - decreased CL- pulmonary oedema and patchy infiltrated. decreased CL b/c of fibrosis in later stage, increase Raw = oedema, emphysematous type changes in later stage

decreased pump efficiency - increased RR and Ve –> resp mm fatigue, increased alveolar dead space

Question 12

ARDS medical management

Answer 12

mechanical vent
prone lying
management of underlying insult

Question 13

Risks of ventilation with ARDS

Answer 13

Barotrauma -high airway pressures
volutrauma - high lung volumes –> regional overinflation

inflammation occurs in response to mechanical ventilatory forces. the combo of these 2 traumas exacerbate the diffuse alveolar damage associated with the syndrome

Question 14

Why do you place a patient with ARDS in prone lying

Answer 14

• alveolar recruitment and reinflation of dorsal (posterior) lung
• improves v/q mismatch
• improves oxygenation

Question 15

Physio managment of ARDS

Answer 15

position
suction
MHI
exercises/early mob