Choice of Anesthetic Agents
The choice of anesthetic agents plays a crucial role in managing acute kidney injury patients. Volatile anesthetics (e.g., sevoflurane, isoflurane) and intravenous agents like propofol are commonly used, but they should be selected and dosed cautiously. Many anesthetics reduce renal blood flow and glomerular filtration rate (GFR), so the goal is to avoid exacerbating renal ischemia. Studies suggest that some anesthetic agents, such as sevoflurane and isoflurane, may offer protective effects against ischemia-reperfusion injury in the kidneys due to their preconditioning effects. Propofol, while generally considered safe, may also have renoprotective properties due to its antioxidant effects.
Hemodynamic Stability
Maintaining stable hemodynamics is paramount in patients with acute kidney injury. Hypotension and fluctuations in blood pressure can lead to renal hypoperfusion and further injury. Intraoperative blood pressure should be closely monitored, with the goal of keeping mean arterial pressure (MAP) above 65–70 mmHg to ensure adequate renal perfusion. Vasopressors such as norepinephrine may be used judiciously to maintain blood pressure without compromising renal perfusion. Aggressive fluid administration should be avoided in oliguric or anuric patients, as it can lead to volume overload and worsen outcomes.
Fluid Management
Balanced crystalloid solutions are preferred over normal saline in acute kidney injury patients to avoid hyperchloremic metabolic acidosis, which can worsen renal function. Colloids, especially synthetic ones such as hydroxyethyl starch, should be avoided as they have been associated with increased risk of AKI in critically ill patients. Intraoperative fluid administration should be carefully titrated, with consideration for the patient’s urine output, volume status, and any underlying cardiac conditions.
Monitoring Renal Function
Close intraoperative monitoring of urine output and kidney function is essential. In cases where urine output is not a reliable indicator of kidney function (e.g., in oliguric or anuric patients), other indicators such as serum electrolytes, acid-base balance, and trends in creatinine levels may provide guidance. Newer biomarkers, such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1), may also offer earlier detection of worsening renal function, though their routine use is not yet widespread.
Electrolyte and Acid-Base Management
Patients with acute kidney injury frequently develop electrolyte disturbances such as hyperkalemia, hyponatremia, and metabolic acidosis. Intraoperative monitoring of potassium levels is critical, particularly in hyperkalemic patients, as high potassium levels can lead to life-threatening arrhythmias. Measures to manage hyperkalemia include calcium gluconate to stabilize the cardiac membrane, insulin with glucose to drive potassium into cells, and potassium-binding agents. Metabolic acidosis should be corrected with bicarbonate as needed, and careful monitoring of acid-base status is essential.
| Parameter | Intraoperative approach |
|---|---|
| Blood pressure | Keep mean arterial pressure above 65–70 mmHg; hypotension and pressure swings cause renal hypoperfusion and further injury |
| Vasopressors | Norepinephrine used judiciously to support pressure without compromising renal perfusion |
| Fluid choice | Balanced crystalloids preferred over normal saline to avoid hyperchloremic metabolic acidosis |
| Colloids | Avoid synthetic colloids such as hydroxyethyl starch — associated with increased AKI risk in critically ill patients |
| Volume in oliguria or anuria | Avoid aggressive fluid administration; titrate to urine output, volume status and any underlying cardiac disease |
| Anesthetic agents | Volatiles and propofol dosed cautiously; sevoflurane and isoflurane may precondition against ischemia–reperfusion injury, and propofol may be renoprotective through antioxidant effects |
| Monitoring when urine output is unreliable | Follow serum electrolytes, acid-base balance and creatinine trends; NGAL and KIM-1 may detect worsening earlier but are not yet in routine use |
| Hyperkalemia | Calcium gluconate to stabilize the cardiac membrane, insulin with glucose to shift potassium intracellularly, potassium-binding agents |
| Metabolic acidosis | Correct with bicarbonate as needed, with continued acid-base monitoring |
