1. Pathophysiology
   1. CNS control
      1. Sensor
         1. O2
         2. PH
      2. Drive
         1. Medular
   2. Ventilation
      1. Respiratory Muscle
         1. Main respiratory muscle
         2. Accessory muscle
      2. Airway
         1. Nasal and oral cavity
         2. Oropharynx
         3. Larynx
         4. vocal cord
         5. Trachea
         6. Bronchus and bronchial trea
         7. Avoelar
         8. Bronchial artery
   3. Oxygenation
      1. Avoelar
      2. Interstial
      3. vessel
   4. Pulmonary Perfusion
      1. Right heart
      2. Pul, Artery
      3. Aveolar capilary
      4. Pul. vein
      5. Left heart
   5. Systemic Delievery and perfusion
      1. Cardiac output
         1. Heart rate
         2. Stroke volume
            1. Preload
            2. Contratility
            3. Afterload
      2. Hb
      3. SaO2
         1. Ventilation
         2. oxygenation
         3. Pul. Perfusion
2. System Approach
   1. Neuropsychiatry
   2. Cardiovascular
   3. Respiratory
   4. Hematology
   5. Metaboloc/Endocrine
3. Type
   1. Exertional dyspnea
   2. Orthopnea
   3. Trepnea
   4. Platypnea