What is the effect of general anesthesia on renal blood flow?

What is the effect of general anesthesia on renal blood flow?

• A. Increased
• B. Decreased
• C. No change
• D. Variable

Answer: (B)

General anesthesia tends to reduce renal blood flow because it lowers systemic arterial pressure and cardiac output, which decreases renal perfusion pressure. Although the kidneys can autoregulate blood flow over a range of mean arterial pressures, anesthesia—especially with volatile agents—can blunt this autoregulation or push the perfusion pressure outside that range. The combination of vasodilation, myocardial depression, and sometimes reduced sympathetic tone leads to a net decrease in renal perfusion, and thus renal blood flow. In practice, maintaining adequate blood pressure and perfusion during anesthesia helps preserve renal blood flow.

General anesthesia tends to reduce renal blood flow because it lowers systemic arterial pressure and cardiac output, which decreases renal perfusion pressure. Although the kidneys can autoregulate blood flow over a range of mean arterial pressures, anesthesia—especially with volatile agents—can blunt this autoregulation or push the perfusion pressure outside that range. The combination of vasodilation, myocardial depression, and sometimes reduced sympathetic tone leads to a net decrease in renal perfusion, and thus renal blood flow. In practice, maintaining adequate blood pressure and perfusion during anesthesia helps preserve renal blood flow.