급성호흡부전

1. 정의 1) 호흡부전(respiratory failure) : PaO2 < 50 mmHg or PaCO2 > 50 mmHg. 2) HRF (Type 1; hypoxemic respiratory failure) : PaO2 < 50 mmHg with FiO2 > 0.5 Ex ; acute lung injury, ARDS 3) HHRF (Type 2; hypoxemic hypercapnic respiratory failure) acute : PaCO2 > 55mmHg, pH < 7.3 chronic : PaCO2 > 55mmHg, pH > 7.3 COPD : PaCO2 > 55mmHg or PaO2가 평상시에 비해 10 mmHg이상 감소 또는 pH < 7.3 Asthma, drug overdose, neurologic weakness : PaCO2 > 45 mmHg 2. Mechanism of hypoxia 3. Mechanism of hypercapnia Failure of alveolar ventilation resulting from either a decrease in minute ventilation (absolute hypoventilation : CNS ...) or an increase in dead space (relative hypoventilation : COPD, Asthma) or a combined forms (COPD). VCO2 = CO2 production, VA = alveolar ventilation Alveolar Ventilation (VA) = Minute Ventilation(VE) - Dead Space Ventilation(VD) 4. Categories of Respiratory Failure 1) Abnormalities of the CNS (1) suppression of the neural drive to breath → hypoventilation, hyperca…
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