Permissive hypofiltration: an alternative view.

If permissive hypercapnia is used in the context of protective ventilation for patients with acute respiratory distress syndrome, it must be highlighted that the alveoli in these patients are still exposed to significant stress. Similarly, early renal replacement therapy is not necessarily a protective therapy for acute kidney injury and loop diuretics are not necessarily harmful. It is conceivable that early initiation of 'protective' low-dose (10 ml/kg/h) continuous renal replacement therapy with zero balanced ultrafiltration in association with administration of (high dose) diuretics may help to rest the kidneys while ensuring preservation of urine output.