Respiratory Distress

Question 1

What are the muscles of inspiration?

Answer 1

Diaphragm is the most important
-with contraction, the abdominal contents move caudally and ventrally and the chest cavity increases in volume in the cranioventral direction
-the ribs are also lifted

External intercostals: with contraction the ribs are pulled cranially and ventrally

Accessory muscles of inspiration (when normal restful breathing is not effective enough)
-include the scalene (elevated first 2 ribs), the sternomastoid (pull the sternum cranially), and the alae nasi (nasal flare)

Question 2

What allows for inspiration?

Answer 2

The increase in volume of the thoracic cavity creates negative pressure–> air will flow from higher pressure (outside the body) to the lower pressure inside the body
-increasing the volume of the chest is an active process- requires energy to activate the musculature

Question 3

Describe the process of expiration

Answer 3

Passive (no energy is needed)
- muscles of expiration are not employed during normal tidal breathing
- elastic properties of the lung and chest wall allow for recoil to equilibrium
- when needed, abdominal wall contraction will lead to an increase in intra-abdominal pressure which will push the diaphragm cranially

Question 4

When abdominal muscles are engaged during breathing- is this more likely an inspiratory or expiratory problem?

Answer 4

Expiratory
- muscles are required to be activated to push air outwards

Question 5

What is the difference between labored breathing, dyspnea, tachypnea, and orthopnea?

Answer 5

Labored breathing- outward signs of breathing difficulty
Dyspnea- sensation of breathlessness (patients are panicking)
Tachypnea- increased respiratory rate
Orthopnea- positional increases in difficulty (often take on a posture of head and neck extension with abducted elbows)

Question 6

Generally, if the problem is localized to inspiration what does this indicate? What about expiration? What if there is increased effort during all phases? Short shallow breathing?

Answer 6

Inspiration: likely an upper respiratory problem
Expiration: likely a lower airway problem
Increased effort during all phases: likely parenchymal disease
Short shallow breathing: likely a pleural space disease

Question 7

What are the 3 most important things to do when you assess a patient to be in respiratory distress?

Answer 7

1. Minimize stress!
2. Oxygen supplementation (above air O2 -20%)
   - doesn’t always help but is relatively safe in the short term
   - be aware that method of delivery may induce stress (O2 cage, mask/flow by, hood, nasal cannula)
3. Provide sedation
   -reduces stress
   -butorphanol is a good option (takes edge off, safe)

*consider intubation when all else fails - reduces stress and work of breathing- short term solution (to perform imaging)
-if available may need to continue mechanical ventilation

Question 8

What is the one contraindication for supplemental oxygen?

Answer 8

Patient is on fire

Question 9

What should your physical exam look like for a patient in respiratory distress?

Answer 9

Brief- do over time to reduce stress
- visual inspection, brief auscultation, TPR, MM assessment

Question 10

Describe the diagnostic work up in cases of respiratory distress?

Answer 10

• no need to kill a patient to get diagnostic tests- that’s what necropsies are for
  -when the patient is calm and stable, you can then perform a full physical, get a blood sample, and imaging
  -most answers will get obtained through imaging (us for pleural effusion, thoracic radiographs)

Question 11

What are the main upper airway diseases that present to the ER?

Answer 11

• Laryngeal paralysis
• Tracheal collapse
• Foreign bodies
• Polyps (more likely in cats)
• Brachycephalic airway syndrome

Question 12

What are the main LOWER airway diseases that present to the ER?

Answer 12

-asthma (chronic bronchitis)
-eosinophilic bronchopneumopathies

Question 13

What are the main parenchymal diseases that present to the ER?

Answer 13

Pneumonia, pulmonary edema
-need to rapidly differentiate between cardiac and non-cardiac causes (based on history, signalment, and triage findings)
-then provide therapy based on assessment (diuretics vs bronchodilators or steroids)

Question 14

T/F: patients in congestive heart failure should be tachycardic and hyperthermic

Answer 14

False- hypothermic due to decreased CO

Question 15

How do you quickly diagnose heart failure on radiographs?

Answer 15

Pulmonary venous distension

Question 16

What will you see on radiographs of patients with pleural space disease?

Answer 16

-potentially pleural effusion, pneumothorax or diaphragmatic hernia
- can also find on ultrasound, or through a thoracic tap (preferred to do this before radiographs as they often arent stable enough for this)

Question 17

What are the different etiologies of thoracic wall disease?

Answer 17

Neurologic disease, muscular disease or orthopedic disease