Disorders of Ventilation

Question 1

Normal PaCO2 at sea level

Answer 1

37-43 mm Hg

Question 2

Clinical features of hypoventilation

Answer 2

Decreased minute ventilation

Increased dead space fall

Question 3

Major categories of hypoventilation

Answer 3

Parenchymal lung and chest wall disease
Sleep disordered breathing
Neuromuscular disease
Respiratory drive disorders

Question 4

Hallmarks of obstructive lung diseases

Answer 4

Increased dyspnea

Increased sputum production

Question 5

Hallmarks of interstitial lung diseases

Answer 5

Progressive dyspnea

Cough

Question 6

Stages of patients with chronic hypoventilation from neuromuscular or chest wall disease

Answer 6

Asymptomatic
Nocturnal hypoventilation
Daytime hypercapnia

Question 7

Hallmark of all alveolar hypoventilation syndromes

Answer 7

INCREASED alveolar PCO2 (PACO2) + PaCO2

Question 8

Suggestive finding in hypoventilation syndromes

Answer 8

Increased plasma bicarbonate in the absence of volume depletion

Question 9

Confirmatory test for hypoventilation syndromes

Answer 9

ABG: Increased PaCO2, Normal pH

Question 10

Screening test identifies patients likely to have OSA, validated in primary care setting

Answer 10

Berlin questionnaire

Question 11

Measures daytime sleepiness however not validated in outpatient primary care settings

Answer 11

Epworth Sleepiness Scale (ESS)

Question 12

Pre-operative evaluation for OSA

Answer 12

STOP-Bang questionnaire

Question 13

Hypoventilation more marked during sleep

Answer 13

Respiratory drive or neuromuscular disorders

Question 14

Potential therapy if with high cervical spinal cord lesions or respiratory drive disorders, may improve QOL

Answer 14

Phrenic nerve or diaphragm pacing

Question 15

BMI >/= 30 kg/m2 +
sleep-disordered breathing +
chronic daytime alveolar hypoventilation (PaCO2 >/= 45 mmHg at sea level in the absence of other known causes of hypercapnia)

Answer 15

Obesity Hypoventilation Syndrome

Question 16

Apnea hypopnea index (AHI) in OHS

Answer 16

> /=5 + daytime sleepiness

Question 17

Risk factors for OHS

Answer 17

BMI >40 kg/m2

AHI >30/hr

Question 18

Treatment for OHS

Answer 18

Weight reduction

CPAP during sleep

Question 19

Absent respiratory response to hypoxia or hypercapnia, mildly Inc PaCO2 while awake, markedly increased PaCO2 during non-REM sleep

Answer 19

Central Hypoventilation Syndrome

Question 20

Treatment of Central Hypoventilation Syndrome

Answer 20

NIPPV
Mech Vent
Phrenic nerve or diaphragmatic pacing

Question 21

Ventilation in excess of metabolic requirements (CO2 production) leading to decreased PaCO2

Answer 21

Hyperventilation

Question 22

ABG finding in hyperventilation

Answer 22

Compensated respiratory with a near-normal pH, low PaCO2 and low calculated bicarbonate