Vasopressors and the kidney

The changes in renal perfusion induced by vasopressors depend on their effects on systemic hemodynamics and renal vascular resistance. Both effects are largely influenced by the patient's underlying condition such as myocardial contractility and vascular responsiveness. A beneficial effect can be expected if mean arterial pressure increases without decreasing cardiac output and if the effect on renal vascular resistance is less pronounced than on systemic vascular resistance. Acute renal failure is associated with loss of renal autoregulation and sepsis is associated with blood pressures below the autoregulatory threshold. Both conditions might therefore benefit from the administration of vasopressors. Many experimental and clinical data indeed suggest a beneficial effect of norepinephrine on the urine output in sepsis. A beneficial effect on renal function (glomerular filtration) is a less consistent finding suggesting that pressure diuresis might be partially responsible for the pressor-induced diuresis. Administration of vasopressors to patients with oliguria should be considered in fluid-resuscitated patients with distributive shock. Whether other vasopressors offer advantages over norepinephrine requires further investigation.