Enhanced renal function associated with intermittent mandatory ventilation in acute respiratory failure

In ten patients suffering from acute respiratory failure (ARF) renal function was evaluated during 2-h periods of intermittent mandatory ventilation (IMV) or controlled mechanical ventilation (CMV). Urine flow, osmolal and creatinine clearances were significantly lower during CMV in comparison to both IMV phases and the free water clearance was less negative. Potassium excretion declined with CMV but remained reduced during the second IMV phase. There was no change in sodium excretion. This study suggests that in order to maintain renal function and prevent water retention the use of IMV should be considered whenever a sufficient mechanical reserve for partial spontaneous ventilation is present.Nomenclature CMV controlled mechanical ventilation - IMV intermittent mechanical ventilation or intermittent mandatory ventilation - IPPB intermittent positive pressure breathing - PEEP positive endexpiratory pressure - F₁O₂ fraction of inspired oxygen - ADH antidiuretic hormone - ARF acute respiratory failureMeasurements V urinary output (ml/min) - P osmolarity in the plasma (mosm) - U osmolarity in the urine (mosm) - C creatineCalculations C_osmol osmolal clearance (ml/min) - C_osmol - free water clearance (ml/min) - V–C_osmol (ml/min) - C_creat creatinine clearance (ml/min) - C_creat - U/P ratio U/PThis paper is dedicated to Martin Zindler on the occasion of his 60th birthday