structural:summarization
Type 4

Type 4 respiratory failure occurs when metabolic (oxygen) demands exceed what the cardiopulmonary system can provide. It often results from hypoperfusion of respiratory muscles as in patients in shock, such as cardiogenic shock or hypovolemic shock. Patients in shock often experience respiratory distress due to pulmonary edema (e.g., in cardiogenic shock). Lactic acidosis and anemia can also result in type 4 respiratory failure. However, type 1 and 2 are the most widely accepted.