Minimal changes in renal hemodynamics
Tendency for bleeding
Patient anxiety
Prolonged procedures
Hypotension with sympathetic block; may cause reluctance to expand volume
Blood pressure control
Duration not dependent on urinary excretion
Less neuromuscular blocking with drugs required
Fio2 can be increased because N2O not necessary
Decreased cardiac output
Hypotension
Biodegradation and potential nephrotoxicity; halothane, 15%–20%; sevoflurane, 5%; isoflurane, 0.2%; desflurane, 0.02%
Hypertension
Greater need for N2O and neuromuscular blockers
Fio2, Fraction of inspired oxygen; N2O, nitrous oxide.
Intravenous fluid management
Perioperative management of fluids and electrolytes in patients with renal disease is critical. The state of hydration affects renin, aldosterone, and antidiuretic levels. Dehydration and hypovolemia lead to elevations in these hormones and to a decline in urinary output.
Perioperative renal function
Surgical patients at high risk for acute renal failure and those with advanced disease who do not require hemodialysis present unique challenges. Preservation of renal function intraoperatively is a major goal. Preservation of renal function is dependent on the maintenance of intravascular volume and cardiovascular stability and on the avoidance of events that cause renal vasoconstriction. Preoperative hydration with 10 to 20 mL/kg of balanced salt solution may be helpful. Intraoperatively, urinary output is the only time monitor for renal function. A urinary output of 0.5 to 1 mL/kg/hr intraoperatively and postoperatively is recommended in these patients.
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