<prompt> Type 4 respiratory failure is due to?ARDSShockPneumoniaPerioperative atelectasis  <response>: Type 4 respiratory failure results from hypoperfusion of respiratory muscles in patients in shock.Normally,respiratory muscles consume5 of the total cardiac output and O2 delivery.Patients in shock often experience respiratory distress due to pulmonary edemaeg.,patients in cardiogenic shock,lactic acidosis,and anemia. Ref:Harrisons medicine -18th edition,page no:2200. 