RT Book, Section A1 Naureckas, Edward T. A1 Adegunsoye, Ayodeji A2 Schmidt, Gregory A. A2 Kress, John P. A2 Douglas, Ivor S. SR Print(0) ID 1201802252 T1 The Pathophysiology and Differential Diagnosis of Acute Respiratory Failure T2 Hall, Schmidt and Wood’s Principles of Critical Care, 5th Edition YR 2023 FD 2023 PB McGraw Hill PP New York, NY SN 9781264264353 LK accesssurgery.mhmedical.com/content.aspx?aid=1201802252 RD 2024/10/10 AB KEY POINTSType I respiratory failure (RF), characterized by severe oxygen-refractory hypoxemia, is caused by a portion of the total pulmonary blood flow (Q˙s/Q˙t) traversing the lung without picking up oxygen due to airspace filling.When blood transport of oxygen is inadequate, treatment includes optimizing cardiac output, hemoglobin concentration, arterial saturation, and lowering oxygen consumption.Optimizing does not mean maximizing, and the end point of each therapeutic approach is the least intervention achieving the goal of that treatment and needs to be individualized.Type II RF is characterized by alveolar hypoventilation and increased PCO2, caused by loss of CNS drive, impaired neuromuscular competence, excessive dead space, or increased mechanical load.Type III RF typically occurs in the perioperative period when factors that reduce functional residual capacity combine with causes of increased closing volume to produce progressive atelectasis.Type IV RF ensues when the circulation fails and resolves when shock is corrected, as long as one of the other types of RF has not supervened.Liberation from mechanical ventilation is enhanced by identifying and correcting the many factors contributing to increased respiratory load and decreased neuromuscular competence.