Respiratory failure Yuanlin Song, MD
Yuanlin Song, M.D. Respiratory failure
Definition and classification 1. Definition Failure of gas exchange due to inadequate function of respiratory system 2. Classification Hypoxemia: lung edema, low FIO2, lung fibrosis Hypercarbia: excess of CO2 production Combination of hypoxemia and hypercarbia: COPD Type L, Il, Ill, IV respiratory failure
Definition and classification 1. Definition: Failure of gas exchange due to inadequate function of respiratory system 2. Classification Hypoxemia: lung edema, low FIO2, lung fibrosis Hypercarbia: excess of CO2 production Combination of hypoxemia and hypercarbia: COPD Type I, II, III, IV respiratory failure
Lung physiology Brain-stem 1. Controller: rhythm 2. Muscle: strong 3. Airway: patent 4. Alveolar: dry 5. Vasculature: intact BSec dl vati aton 2 Efec of Pacm haemoglobin on veat at CO2 normal haemoglobin Paco, erm Hg)
Lung physiology Brain-stem 1. Controller: rhythm 2. Muscle: strong 3. Airway: patent 4. Alveolar: dry 5. Vasculature: intact O2 CO2
Lung function test ERV FRC RV
Compliance (c) Static compliance measured in absence of flow o C=AV/AP= 1/E where e=elastance, V=volume, P=pressure =AV/(Pairspace-Ppleura) Pleura esophageal total=AV/(Pairspace-Patmospheric) total chest wall Etotal= Elmg Chest wall COPD, asthma 3100 normal Pulm Fibrosis. fibrothorax Pressure
C=ΔV/ΔP = 1/E where E=elastance,V=volume, P=pressure Clung = ΔV/(Pairspace –Ppleura), Ppleura = Pesophageal Ctotal = ΔV/(Pairspace-Patmospheric) . Ctotal Clung Cchest wall 1 1 1 Etotal Elung Echest wall % Predicted Volume Pressure 100 0 normal COPD, asthma Pulm. Fibrosis, fibrothorax Static compliance measured in absence of flow