Obesity Hypoventilation Syndrome

Question 1

Obesity Hypoventilation Syndrome

Answer 1

Increased work of breathing & increased needs to augment minute ventilation & maintain adequate alveolar ventilation =>

1. Patient can increase ventilatory drive & minute ventilation => normal ventilation & eucapnia => OSA or Simple Obesity.
2. Patient cannot increase ventilatory drive & minute ventilation => Hypoventilation especially during sleep, hypercapnia & hypoxemia => OSA or OSA + OHS

Question 2

Affect on ventilation

Answer 2

Impaired alveolar ventilation

Question 3

Affect on PaCO2

Answer 3

Increased

Question 4

Affect on PaO2

Answer 4

Reduced

Question 5

Affect on chest wall compliance

Answer 5

Reduced

Question 6

Symptoms

Answer 6

• Progressive dyspnoea
• Dry cough
• Headache
• Confusion
• Lethargy

Question 7

Signs

Answer 7

• Finger clubbing
• Obesity, kyphosis, scoliosis
• Fibrotic crepitations
• Clinical signs of pleural effusions of ascites
• Cyanosis

Question 8

PFTs

Answer 8

Restrictive pattern: decreased FVC & FER>70.

Question 9

ABGs

Answer 9

Type I resp failure & type II resp failure

Question 10

Pleural ultrasound

Answer 10

Diaphragmatic excursion, pleural effusions

Question 11

Abdominal ultrasound

Answer 11

Ascites

Question 12

Bloods

Answer 12

Connective tissue disease, eosinophilia