Acute Respiratory Failure

Question	Answer
Criteria for acute respiratory failure (2)	Hypoxia (PaO2 < 60) Hypercapnia (PaCO2 > 50)
Cause of V/Q mismatch	Defect in either alveolar ventilation (e.g., pulmonary edema) or perfusion (e.g., PE)
V/Q mismatch typically leads to _________ without _________.	Hypoxia without hypercapnia
V/Q mismatch vs. shunt: Which is responsive to supplemental oxygen	V/Q mismatch
Causes of shunts (3)	- Atelectasis - Fluid buildup in alveoli (pulmonary edema, pneumonia) - Congenital heart disease (R-to-L flow)
Alveolar-arterial oxygen difference (A-a gradient) is normal when __________ is the cause of hypoxemia. It is increased in most other causes.	hypoventilation
Low-flow oxygen delivery systems (2)	Nasal cannula Simple face mask
Flow rate (L/min) and max FiO2 for low-flow O2-delivery systems	Nasal cannula: 1-6 L/min; up to 40% FiO2 Simple face mask: 5-10 L/min; 40-60% FiO2
High-flow oxygen delivery systems (3)	Venturi mask Nonrebreathing mask High-flow nasal cannula
Flow rate (L/min) and max FiO2 for high-flow O2-delivery systems	Venturi mask: 4-10 L/min - up to 40% FiO2 Nonrebreathing mask: up to 15 L/min - up to 70-90% FiO2 High-flow nasal cannula: up to 40 L/min - up to 40% FiO2

Resource summary

	Created by Aaron Samide about 8 years ago