Table 3 |.

Clinical contexts for fluid administration in patients with or at risk of AKI

Clinical context	Reasons for fluid administration and potential benefits	Challenges and risks of fluid administration
Age and demographics
Children	• Diseases with volume losses	• Narrow window between hypovolemia and fluid overload • Clear adverse effects of fluid overload
Adults	• Indications likely to be context-dependent	• Adverse effects of “one size fits all” approach to fluid management • Uncertain definition of clinically significant fluid overload • In patients with heart disease, poor cardiac reserve to tolerate hypovolemia and hypervolemia • In patients with diastolic dysfunction, risk of potentiating venous hypertension and renal congestion in fluid overload
Setting
Resource-limited	• Specific conditions including diarrheal illness	• Differing spectrum of disease • Potentially delayed presentation to secondary care • Limited range of therapeutic options
Pre-hospital Ward/ICU	• Impetus toward early resuscitation • Dynamic phases of illness associated with hypovolemia	• Lack of advanced hemodynamic monitoring • Inappropriate administration of maintenance fluid • Risk of “fluid creep” leading to insidious fluid overload
Comorbid diseases
CKD	• Inability to conserve salt and water	• Risk of hypovolemia • Inability to handle fluid excess • Predisposition to AKI
CHF or severe valvular disease	• Poor cardiac reserve to tolerate hypovolemia	• Potentiation of adverse effects of fluid overload • Potentially pre-existing interstitial edema • Higher CVP associated with worsening kidney function
Severe chronic liver disease	• Intravascular hypovolemia despite peripheral edema	• Precipitation of fluid accumulation
Acute conditions
Dehydration	• Acute free water deficit	• Challenges of managing relative water and sodium deficits
Hypovolemia	• Salt and water deficit	• Need for consensus on optimal endpoints of resuscitation
Hemorrhage	• Acutely impaired oxygen delivery	• Dilution of hemoglobin may offset effects of fluid resuscitation on oxygen delivery
Sepsis	• Intravascular hypovolemia	• Endothelial dysfunction, capillary leak, fluid losses to interstitium, and vasodilation • Lack of evidence for goal-directed hemodynamic therapy
Cardiogenic shock	• Inability to tolerate hypovolemia • Venodilation due to inotropic drugs	• Risk of pulmonary edema • Association between high CVP and adverse kidney outcome
Major surgery	• Anesthesia-induced venodilation and vasodilation • Perioperative fluid losses	• Inappropriate administration of maintenance fluid and “fluid creep” leading to insidious fluid overload
Nephrotoxic exposure	• Dilution of filtered toxins	• Risk of fluid overload
Abdominal compartment syndrome	• Maintenance of visceral and renal perfusion	• Risk of venous hypertension
ARDS	• Reduced cardiac preload due to high intrathoracic pressure	• Risk of worsening alveolar edema
Rhabdomyolysis/crush injury	• Dilution of myoglobulin • Intravascular hypovolemia due to fluid losses to injured muscle	• Development/worsening of compartment syndrome
Timing
Biomarker-positive states	• Prevention of progression to overt AKI	• Presence of early renal injury does not signify need for volume replacement
AKI stage	• Reversal of early AKI	• Inappropriate attempts to “reverse” established AKI resulting in fluid overload
Oliguria/anuria	• Oliguria as an indication of acute compensated hypovolemia	• Multiple etiologies of oliguria beyond hypovolemia • Vicious cycle of fluid overload resulting in worsening kidney function

AKI, acute kidney injury; ARDS, acute respiratory distress syndrome; CHF, congestive heart failure; CKD, chronic kidney disease; CVP, central venous pressure; ICU, intensive care unit.