Obstructive Sleep Apnea

Question 1

Pulmonary hypertension benchmark

Answer 1

Pulmonary arterial pressure is higher than 20 mmHg at rest (normal is 10-14 mmHg)

Question 2

Symptoms of Obstructive sleep apnea

Answer 2

Shortness of breath
- most common

Chest pains

Palpitations

RHF signs

Syncope with exertion

Malaise

Cough/hemoptysis

Voice hoarseness due to impingement of the recurrent laryngeal nerve from pulmonary artery (super rare)

Signs:

• S2 split w/ S3/4 heart sound
• tricuspid regurgitation murmur
• JVD
• hepatomegaly w/ elevated liver enzymes
• Ascites
• similar to COPD on flow volume loops

Question 3

What benchmark of DLCO is required to start really thinking about pulmonary hypertension?

Answer 3

< 40% DLCO

Question 4

Pathophysiology of PH

Answer 4

Causes are not completely understood
- thought to be possible narrowing of pulmonary arteries leading to increase pulmonary resistance

Important to diagnosis ASAP since untreated/diagnosed PH = cor pulmonale
- poor prognosis at this point; 5yr survival = 30%

remember to think massive PE as diagnosis If acute rapid PH is present and signs of cor pulmonale occur

Question 5

Classes of pulmonary artery hypertension

Answer 5

Group 1: idiopathic (this is PAH)
- 85% is familial genetics with 75% of the 85% is due to loss of BMPR2 receptors 
Other causes in group 1
* drugs 
* connective tissue disorders 
* autoimmune infections (especially HIV)
* portal HTN 
* left-right congenital shunting 

Group 2: LHF (PH)

• MOST COMMON CLASS OF PH
• diagnosed with symptoms of LHF and ECG showing sings of RBBB, CHF and LVH
• current data suggests OSA is here

Group 3: hypoxic vasoconstriction (PH)

• WHO says THIS IS WHERE OSA IS LOCATED
• COPD and altitude changes also occur here
• this is also the group where cor pulmonale is most likely to occur

Group 4: chronic microemboli (PH)

• VQ mismatches with VQ scan usually diagnosises this
• perfusion portion = left side
• ventilation portion = right side

Group 5: everything else (PH)

• most common are
• hemolytic anemia
• systemic diseases such as sarcoidosis
• metabolic disorders
• all other congenital heart diseases other than left-right shunting

Question 6

Definition of sleep apnea

Answer 6

Recurrent nocturnal cessation of breathing for at least 10 seconds

Lab finds of OSA

• neck circumference > 17 inches = OSA
• elevation RBCs and hematocrit w/ normal WBCs and platelets
• ABG shows low O2 and possibly high CO2 (not always though)

Question 7

Sequelae of OSA

Answer 7

2nd polycythemia

Systemic HTN

Cardiac arrhythmias

Sudden death

Question 8

Two types of sleep apnea

Answer 8

Obstructive (OSA)

• excessive parapharyngeal tissue
• being obese
• adenotonsillar hypertrophy
• chronic hypoxia/ hypercapneic

Central

• toxins
• trauma
• infections
• stroke/ bleeding
• advanced Heart failure

Question 9

Treatment for obstructive sleep apnea

Answer 9

1st is always lifestyle choices

• lose weight and change diet
• modify sleeping position
• avoid alcohol and sedatives

2nd is BiPAPor CPAP

• BiPAP = use if pneumonia/HF or central causes are present w/ minimal CO2 retention
• CPAP = use if retaining CO2

Alternative treatments (is 1st and 2nd dont work)

• surgery
• oral appliances

Question 10

Treatment of PAH/PH

Answer 10

must determine primary cause 1st and treat that