<prompt> Which of the following is the best parameter to assess fluid intake in. Polytrauma patientUrine outputBlood pressurePulsePulse oximetry  <response>: The urine output is an impoant clinical parameter of renal function and blood volume status, especially in critically ill multiple trauma patients. In the present study, the minute-to-minute urine flow rate and its variability were analyzed in hypotensive multiple trauma patients during the first 6 h of their ICU stay. It is used to assess the tissue perfusion 