Immediate Management of Acute Kidney Injury Due to Septic Shock
The immediate management of AKI due to septic shock requires isotonic crystalloids for volume expansion along with vasopressors to maintain hemodynamic stability, following a protocol-based approach to optimize tissue perfusion and prevent further kidney damage. 1
Initial Resuscitation Strategy
Fluid Management
- Use isotonic crystalloids rather than colloids as initial management for intravascular volume expansion 1
- Administer at least 30 mL/kg of IV crystalloid fluid within the first 3 hours 2
- Balanced crystalloids (like lactated Ringer's) may be preferred over normal saline to avoid hyperchloremic metabolic acidosis 1
- Avoid hydroxyethyl starch solutions as they increase mortality and need for renal replacement therapy 1
Vasopressor Support
- Implement vasopressors in conjunction with fluids to maintain adequate perfusion pressure 1
Hemodynamic Monitoring
- Use protocol-based management of hemodynamic parameters 1
- Consider dynamic variables (passive leg raise test, cardiac ultrasound) rather than static variables to predict fluid responsiveness 2
- After initial resuscitation, adopt a more conservative approach to fluid management to prevent complications of fluid overload 2
Source Control and Antimicrobial Therapy
- Obtain blood cultures before starting antibiotics 2
- Administer broad-spectrum antibiotics within 1 hour of sepsis recognition 2
- Identify and control source of infection as rapidly as possible 2
Supportive Care for AKI
Metabolic Management
- Implement insulin therapy targeting plasma glucose of 110-149 mg/dL (6.1-8.3 mmol/L) 1
- Avoid restriction of protein intake with the aim of preventing or delaying initiation of renal replacement therapy 1
- Provide nutrition preferentially via the enteral route 1
Medication Management
- Avoid nephrotoxic medications when possible 1
- If aminoglycosides are necessary, administer as single daily dose and monitor drug levels 1
Renal Replacement Therapy Considerations
- Consider early initiation of RRT in patients with severe AKI and septic shock
- Recent data shows that 42.7% of patients with septic shock develop stage 3 AKI, with 6.4% requiring RRT 3
Monitoring and Prevention of Complications
- Apply oxygen to achieve saturation >90% 2
- Place patients in semi-recumbent position (head of bed raised 30-45°) 2
- Provide DVT prophylaxis with subcutaneous heparin 2
- Provide stress ulcer prophylaxis for patients with risk factors for GI bleeding 2
- Transfuse red blood cells when hemoglobin < 7.0 g/dL (target 7.0-9.0 g/dL) once tissue hypoperfusion has resolved 2
Pathophysiological Considerations
The pathogenesis of septic AKI is complex, involving microvascular dysfunction, inflammation, and metabolic reprogramming 4, 5. Recent evidence suggests that in the first 48 hours, the defects may be functional rather than structural, with renal medullary hypoxia due to redistribution of intra-renal perfusion emerging as a critical mediator 4.
Common Pitfalls to Avoid
- Overzealous fluid administration - After initial resuscitation, excessive fluid can worsen outcomes and kidney function 1, 6
- Delayed antimicrobial therapy - Each hour delay increases mortality; administer within 1 hour 2
- Using hydroxyethyl starch solutions - These decrease survival and should be avoided 1
- Relying solely on serum creatinine - This is a late marker of kidney injury; monitor urine output and consider novel biomarkers when available 5
- Inadequate source control - Failure to identify and control the source of infection promptly worsens outcomes 2
PiCCO-guided fluid resuscitation strategies have shown promise in reducing fluid load and improving renal function compared to traditional CVP-guided approaches in patients with septic shock and AKI 6.