What is the recommended treatment for burns complicated by Acute Kidney Injury (AKI)?

Management of Burns Complicated by Acute Kidney Injury (AKI)

Balanced crystalloid solutions should be used as first-line fluid resuscitation for burns complicated by AKI, with Ringer's Lactate being the preferred option to reduce the risk of worsening kidney injury. 1

Initial Fluid Resuscitation

• Adult burn patients with total burned body surface area (TBSA) ≥15% and pediatric burn patients with TBSA ≥10% should receive 20 mL/kg of intravenous crystalloid solution within the first hour of management 1
• Balanced crystalloid solutions, particularly Ringer's Lactate, should be used as the first-line fluid resuscitation solution to minimize the risk of hyperchloremic metabolic acidosis and acute kidney injury 1
• Normal saline (0.9% NaCl) should be avoided as it is associated with a higher incidence of acute kidney injury compared to balanced solutions 1
• Intravenous access should be obtained as soon as possible, preferably in unburned areas; if IV access cannot be rapidly obtained, an intraosseous route is recommended 1

Ongoing Fluid Management

• After initial resuscitation, fluid requirements should be calculated using formulas such as the Parkland formula (2-4 mL/kg/%TBSA over the first 24 hours) 1
• For children, higher fluid volumes may be required (approximately 6 mL/kg/%TBSA in the first 48 hours) due to their higher body surface area/weight ratio 1, 2
• Fluid administration should be adjusted based on clinical response, with urine output being a key parameter (target: 0.5-1 mL/kg/hour) 1, 2
• Monitor for both under-resuscitation (which can worsen AKI) and over-resuscitation ("fluid creep"), which can lead to compartment syndromes and worsen outcomes 2

Albumin Administration

• Human albumin should be administered to severe burns patients with TBSA >30% after the first 6 hours of management 1
• Target albumin levels >30 g/L with doses generally around 1-2 g/kg/day 1
• Albumin administration can reduce the volume of crystalloids required, potentially decreasing complications related to fluid overload including congestive acute kidney injury 1
• In pediatric patients, early administration of albumin (8-12 hours post-burn) has been shown to decrease crystalloid requirements and improve outcomes compared to later administration 1

Management of Compartment Syndrome

• Monitor for compartment syndrome, which can worsen AKI through increased intra-abdominal pressure 1
• Consider escharotomy for third-degree circumferential burns that cause constriction and increased compartmental pressure 1
• Escharotomy should be performed at a Burns Center whenever possible; if transfer is not feasible, specialist advice should be obtained 1
• Abdominal compartment syndrome can lead to decreased cardiac output, reduced pulmonary compliance, and acute renal failure 1

Hemodynamic Monitoring and Support

• If hypotension persists despite appropriate fluid resuscitation, vasopressors can be used 1
• Cardiac function and intravascular volume status should be evaluated using echocardiography or alternative hemodynamic monitoring 1
• Protocol-based management of hemodynamic parameters is suggested to prevent development or worsening of AKI in high-risk patients 1
• Consider advanced hemodynamic monitoring for patients with persistent oliguria despite resuscitation 1

Nutritional Support

• Provide 20-30 kcal/kg/day total energy intake in patients with AKI 1
• Avoid protein restriction with the aim of preventing or delaying initiation of renal replacement therapy 1
• Administer 0.8-1.0 g/kg/day of protein in noncatabolic AKI patients without need for dialysis, 1.0-1.5 g/kg/day in patients with AKI on RRT, and up to 1.7 g/kg/day in patients on continuous renal replacement therapy (CRRT) 1
• Provide nutrition preferentially via the enteral route 1

Renal Replacement Therapy

• Initiate renal replacement therapy early if AKI progresses despite initial management measures 3
• Renal replacement therapy has significantly improved the mortality of burn patients with AKI 3
• Hemodialytic therapy is used both for water balance management in patients requiring massive fluid infusions and for blood purification to control metabolic state, acid-base balance, and electrolyte abnormalities 4

Monitoring and Prevention of AKI

• Monitor for signs of AKI including decreased urine output and rising serum creatinine and blood urea nitrogen 3, 5
• Be aware that early burn AKI (0-3 days after injury) is typically due to hypovolemia, poor renal perfusion, and precipitation of denatured proteins, while late AKI (4-14 days) is often due to sepsis, multi-organ failure, and nephrotoxic drugs 3
• Avoid nephrotoxic medications when possible 4
• Risk factors for AKI in burn patients include advanced age, large TBSA, full-thickness burns, inhalation injury, and sepsis 5

Special Considerations

• In resource-limited settings where IV access is challenging, consider enteral resuscitation with oral rehydration solution, which has shown promise in reducing burn-induced kidney injury 6
• In extreme conditions such as disaster sites, peritoneal resuscitation may be considered as an alternative when IV resuscitation is delayed or difficult 7