What is the primary cause of acute kidney injury following major surgery?

The primary cause of acute kidney injury (AKI) following major surgery is often attributed to hypovolemia or hypotension. During and after major surgical procedures, patients can experience significant fluid shifts, blood loss, and alterations in hemodynamics, which can lead to reduced perfusion of the kidneys. When the kidneys do not receive adequate blood flow, their ability to filter waste and maintain electrolyte balance is impaired, resulting in AKI.

Hypovolemia, which refers to a decreased volume of blood in the body, can occur due to various factors during surgery, including bleeding, inadequate fluid resuscitation, and maintenance of blood pressure. In addition to hypovolemia, hypotension can occur due to the effects of anesthesia or volume loss, further exacerbating renal ischemia. This combination can lead to prerenal azotemia, where the kidneys suffer from a lack of perfusion without any intrinsic damage to the renal tissue itself.

Other potential causes of AKI, such as drug toxicity, sepsis, and obstruction, also contribute to renal injury but are less frequently encountered as the primary cause in the immediate postoperative setting. Drug toxicity may occur due to nephrotoxic medications being administered during surgery; however, it typically manifests more