- The utility of serum creatinine measurement as an indicator of glomerular filtration rate (GFR) is limited in critical illness: the rate of creatinine production, and its volume of distribution, may be abnormal in the critically ill patient, and the serum creatinine concentration often does not accurately reflect GFR in the physiological disequilibrium of acute kidney injury (AKI).
- Creatinine clearance measurement is the most accurate method available for clinically assessing overall renal function.
- The accumulation of morphine and meperidine metabolites has been reported to prolong respiratory depression in patients with kidney failure.
- Succinylcholine can be safely used in patients with kidney failure in the absence of hyperkalemia at the time of induction.
- Extracellular fluid overload from sodium retention, in association with increased cardiac demand imposed by anemia and hypertension, makes patients with end-stage renal disease particularly prone to congestive heart failure and pulmonary edema.
- Delayed gastric emptying secondary to autonomic neuropathy may predispose patients to aspiration perioperatively.
- Controlled ventilation should be considered for patients with kidney failure. Inadequate spontaneous or assisted ventilation with progressive hypercarbia under anesthesia can result in respiratory acidosis that may exacerbate preexisting acidemia, lead to potentially severe circulatory depression, and dangerously increase serum potassium concentration.
- Correct anesthetic management of patients with renal insufficiency is as critical as management of those with frank kidney failure, especially during procedures associated with a relatively high incidence of postoperative kidney failure, such as cardiac and aortic reconstructive surgery.
- Intravascular volume depletion, sepsis, obstructive jaundice, crush injuries, and renal toxins such as radiocontrast agents, certain antibiotics, angiotensin-converting enzyme inhibitors, and NSAIDs are major risk factors for acute deterioration in renal function.
- Renal protection with adequate hydration and maintenance of renal blood flow is indicated for patients at high risk for AKI and kidney failure undergoing cardiac, major aortic reconstructive, and other surgical procedures associated with significant physiological trespass. The use of mannitol, low-dose dopamine infusion, loop diuretics, or fenoldopam for renal protection is controversial and without conclusive proof of efficacy.
Acute kidney injury (AKI) is a common problem, with an incidence of up to 5% in all hospitalized patients and up to 8% in critically ill patients. Postoperative AKI may occur in 1% or more of general surgery patients, and up to 30% of patients undergoing cardiothoracic and vascular procedures. Perioperative AKI greatly increases hospitalization costs, mortality rate, and perioperative morbidity, including fluid and electrolyte derangements, major cardiovascular events, infection and sepsis, and gastrointestinal hemorrhage. Preoperative risk factors for perioperative AKI include preexisting kidney disease, hypertension, diabetes mellitus, liver disease, sepsis, trauma, hypovolemia, multiple myeloma, and age greater than 55 years. The risk of perioperative AKI is also increased by exposure to nephrotoxic agents such as nonsteroidal antiinflammatory drugs (NSAIDs), radiocontrast agents, and antibiotics (see Table 29-4). When addressing abnormalities in renal function, the clinician must possess a thorough understanding of the differential diagnosis of AKI (Figure 30-1).
Differential diagnosis of ...