Optimal fluid management in sepsis

Abstract

Sepsis clinically manifests as life-threatening organ dysfunction due to a dysregulated host response to infection.1 Optimal fluid resuscitation is relevant for all sepsis patients, and perhaps it is most important for those with septic shock. Septic shock is defined as a subset of sepsis in which particularly profound circulatory, cellular, and metabolic abnormalities are associated with a greatest risk of mortality, and septic shock is clinically identified as sepsis patients with serum lactate level >2 mmol/L and who require vasopressor infusion to maintain a mean arterial pressure ≥ 65 mm Hg in the absence of hypovolemia. Sepsis is among the most common conditions in the intensive care unit (ICU), accounting for up to half of all hospital deaths and being the third leading cause of death overall in the United States.2 Sepsis and septic shock are medical emergencies for which treatment and resuscitation should begin immediately. The goals of fluid resuscitation for these patients are: a) to rapidly replace intravascular volume and restore tissue perfusion, and b) to minimize organ dysfunction through timely interventions that either halt or reverse the physiologic derangements. If hypoperfusion is present, at least 30 mL/kg of IV crystalloid fluid should be given rapidly, and additional fluids should be guided by frequent reassessment of hemodynamic status, preferably using dynamic indices to indicate the likelihood of a beneficial response to fluid administration. Fluid administration should be targeted to achieve a MAP of at least 65 mm Hg, and to normalize lactate in patients with elevated lactate due to hypoperfusion.3 Balanced crystalloids are the fluid of first choice for sepsis resuscitation based on ready availability and taking medication costs into account. Use of 0.9% saline compared to a balanced crystalloid, such as lactated Ringer's or PlasmaLyte, produces more kidney dysfunction and with a greater risk of dying.4 The individual side effect profiles may best differentiate the natural and synthetic colloids. Albumin may be considered for administration to sepsis patients with refractory shock or who have received substantial amounts of crystalloid fluids, but should not be administered to patients with severe traumatic brain injury.5 Hydroxyethyl starch (HES) products should not be administered to patients with sepsis because of increased risk of acute kidney injury and death. Gelatin solutions are not recommended in sepsis.Norepinephrine is the vasopressor of first choice for patients with septic shock, and should be administered to achieve a mean arterial pressure of at least 65 mm Hg after excluding hypovolemia as a cause for hypotension. The selection of a second line vasopressor, such as vasopressin, dopamine, phenylephrine, epinephrine or angiotensin-2, depends on patient factors such as underlying cardiac dysfunction, presence of arrhythmias, and current response to vasoconstrictor or inotropic agents. Dopamine should not be used for renal perfusion or protection and it should be avoided in patients with tachyarrhythmias.