Management of loop diuretic resistance in the intensive care unit

Purpose. The management of loop diuretic resistance in the intensive care unit (ICU) is reviewed. Summary. Volume overload, a common complication of fluid resuscitation, is frequently encountered in the ICU and is associated with numerous adverse effects, including pulmonary and peripheral edema, acute lung injury, and pleural effusions. Loop diuretics are used to treat volume overload and acute renal failure and to ameliorate their associated complications. When administered intravenously, these drugs induce vigorous and prompt diuresis, which may result in negative fluid balance. This may also result in significant adverse effects, including electrolyte imbalance, ototoxicity, and volume contraction. Prolonged use of loop diuretics may lead to loop diuretic resistance, a frequent observation in the ICU. Three general mechanisms are used to explain loop diuretic resistance: rebound sodium retention, postdiuretic effect, and diuretic braking. While very few agents have joined the armamentarium and no new strategies have been developed to deal with this phenomenon, several options are available to clinicians for managing loop diuretic resistance, including salt restriction, administration of i.v. loop diuretics, continuous infusion of loop diuretics, and combination therapy using loop diuretics and thiazides. Conclusion. Loop diuretic resistance presents a challenge for clinicians in the ICU setting. Strategies to improve patients' responsiveness to these agents include fluid and salt restriction, switching from oral to i.v. loop diuretics, increasing diuretic dose, continuous infusion, and combination therapy with thiazides. Several of these strategies may be used concurrently to combat diuretic resistance and promote symptomatic relief of edema in the critically ill patient.