COPD Cliffnotes

Question 1

What is COPD?

Answer 1

A obstructive disease that causes airflow limitation not fully reversible with bronchodilators.

• Consists of chronic bronchitis and emphysema
• Excessive, chronic inflammation, hyperinflation, and bronchospasm

Question 2

What is chronic bronchitis defined by?

Answer 2

Productive cough for 3 months in each of 2 successive years.

• prone to pneumonia —> hemophilia influenza B
• Chronic inflammation, excessive mucus production, bronchospasm, air trapping, and hyperinflation are key anatomical changes

Question 3

What is emphysema?

Answer 3

Permanent enlargement of alveoli

• destruction of pulmonary capillaries, weak distal airways, air trapping, and hyperinflation

Question 4

What other reason could COPD occur if not from an external environment or lifestyle?

Answer 4

A-1 anti trypsin (AAT) deficiency

• Genetic condition that prevents AAT from being produced in the body, predisposing the lungs to airway damage
• in a nutshell, without AAT an enzyme gradual breaks down the the alveoli walls leading to reduce surface area and stiffer lungs

Question 5

Chest x-ray findings for COPD?

Answer 5

Flattened ribs, hyperlucent lung fields, flattened diaphragms

Question 6

Gold standard for COPD diagnosis?

Answer 6

PFT

• FEV1/FVC ratio < 0.7
• FEV1 is used to determine severity of disease i.e >80 mild, 50-80 moderate etc etc

Question 7

What is used to determine COPD severity irrespective of PFT tests?

Answer 7

CAT and MMRC score

• CAT = 8 item questionnaire
• mmRC scale of 4 on breathless on walking

Question 8

COPD management

Answer 8

Reduce risk factors and manage exacerbations

• pharmacology
• low RR (allow time for exhalation)

Question 9

Anatomic alternations caused by chronic bronchitis?

Answer 9

Thickening of bronchial walls, increased mucus production, and inflammation leading to narrowed airways

Question 10

Anatomical alterations caused by Empysema?

Answer 10

Destruction of alveolar walls and capillaries, causing large irregular air spaces (bullae) and loss of elastic recoil

• impedes airflow and air trapping

Question 11

COPD effect on Cardiopulmonary system?

Answer 11

1. Increased WOB due to hyperinflation and air trapping
2. Hypoxemia/hypercapnia due to impaired gas exchange (low v/q)
3. Pulmonary hypertension and Cor pulmonale due to hypoxemia which increases the heart demand

Question 12

How is Oxygenation/Ventilation/Perfusion affected by COPD

Answer 12

• Oxygenation: Impaired due to alveolar destruction and V/Q mismatch, often resulting in hypoxemia.
• Ventilation: Difficult due to airway obstruction and loss of elastic recoil, leading to air trapping and hypercapnia.
• Perfusion: Blood flow is diverted away from poorly ventilated alveoli (a compensatory response), leading to V/Q mismatch and further reducing oxygenation.

Question 13

What are signs of increased airway resistance?

Answer 13

• EtCO2 with a slow rise/ramp before inspiration
• flow waveform not returning to baseline on a vent

Question 14

COPD Ventilation Goals?

Answer 14

PRVC w/tight settings

• Permissive hypercapnia ph >7.25 if needed
• SpO2 88-92% for CO2 retainers
• Vt 6-8 ml/kg, Plats < 30, RR 10-14
• PEEP@80% of total peep to reduce intrinsic PEEP
• Ti < 1s, Te 2-4s
• Heated circuit to reduce dead space

Question 15

What are asthma ventilation goals?

Answer 15

PRVC w/tight settings

• Permissive hypercapnia ph >7.25 if needed
• SpO2 88-92% for CO2 retainers
• Vt 6-8 ml/kg, Plats < 30, RR 10-14
• PEEP 0-5
• Ti < 1s, Te 2-4s (longer TEs)
• Heated circuit to reduce dead space

Question 16

How does pulmonary hypertension (increased PVR) affect the heart

Answer 16

Increases myocardial work leading to RV failure/cor pulmanle

• Increased PVR = Increased afterload = pressure overload meaning RV dilates/fails = cor pulmanole
• Clinically = worsen RV function, edema, JVD, Hepatomeagly, ascites and lower CO = increased fatigue w/worsened function

Question 17

Low v/q vs High v/q

Answer 17

• Low v/q ratio = perfusion exceeds ventilation
• high v/q ratio - ventilation exceeds perfusion

Question 18

Why is polycythemia associated with COPD patients?

Answer 18

Chronic hypoxemia stimulates increased BRC production via erythropoietin (EPO) from the kidneys

• EPO is released by the kidneys to stimulate the bone marrow to produce more RBCs. Its a compensation mech.

Question 19

Why is polycythemia (thick blood) bad?

Answer 19

polycythemia worsens pulmonary hypertension and strains the heart.

• Increases risk of stroke, thromboembolism, and cor pulmonale