Acute renal failure in surgical patients. Causes, clinical patterns, and care

Postoperative acute renal failure in patients with gynecologic malignancies: analysis of 10 cases and review of the literature

OBJECTIVE

Postoperative acute renal failure (PO-ARF) is an important cause of mortality among surgical patients. Although there have been many reports on PO-ARF after cardiac surgery and liver transplantation, less is known about the risk of PO-ARF after gynecologic operations. We aimed to investigate the risk of PO-ARF on gynecologic malignancy operations.

METHODS

1,155 patients' medical charts were reviewed who underwent therapeutic surgery for gynecologic malignancies from January 1, 2005 to December 31, 2007, at the Asan Medical Center, Seoul, Korea.

RESULTS

Of these, 10 patients, comprising 0.89% of those who underwent radical hysterectomies and 0.86% of those who underwent debulking operations, were diagnosed with PO-ARF. Their mean age was 61.9+/-10.1 years. Five patients had preoperative risk factors. Mean operating time was 360.8+/-96.2 minutes. Five patients experienced intra-operative hypotension and all patients were given blood transfusions during surgery. Eight patients underwent hemodialysis, with two continuing on dialysis to date. Only two patients fully recovered.

CONCLUSION

Patients undergoing surgery for gynecologic malignancies may be at high risk for PO-ARF, because of old age, long operation times, and profuse bleeding. It is necessary to monitor these patients for postoperative renal function and urine output. If a postoperative oliguric state is detected, aggressive volume expansion should be started immediately, followed by hemodialysis.

The patient at risk for acute renal failure. Recognition, prevention, and preoperative optimization

Despite major advances in critical care medicine and extracorporeal renal support, the treatment of established postoperative ARF remains unsatisfactory and costly. The essential elements of perioperative renal preservation are early recognition of high-risk patients, preoperative optimization of fluid status and cardiovascular performance, intraoperative maintenance of renal perfusion, and avoidance of nephrotoxins. Pharmacologic interventions directed at preventing postoperative ARF are under intense investigation but presently are limited to renal transplant surgery.

Perioperative complications of anesthesia

An overview of several perioperative complications and their management strategies is presented. Operative hypothermia, malignant hyperthermia, bronchospasm, and side effects of spinal opioid agents are discussed. Ramifications of these complications may extend well beyond the operative period and influence patient outcome. Therefore, it is necessary that the surgeon have a fundamental understanding of the pathophysiology and modalities of treatment in the context of anesthesia and surgery.

Pathophysiology and prevention of acute renal failure: the role of the anaesthetist

Ischaemic renal tubular damage in the perioperative period can lead to acute renal failure (ARF) with a very high mortality rate (60-75 per cent). Recent research suggests that this tubular injury is caused by an imbalance of the oxygen supply and demand of medullary thick ascending limb (mTAL) tubular cells. High oxygen demand is secondary to active reabsorption of solute which is increased in states of intravascular volume depletion. The restricted supply of oxygen is secondary to the organization of blood flow to the inner medulla. Because the vasa recta loop into the inner medulla and a countercurrent exchange process for oxygen is established, the oxygen tension in this area may normally be as low as 10-20 mmHg. In hypoperfusion states, mTAL injury occurs and is exacerbated by intravascular volume depletion, hypoxaemia and endothelial cell swelling which reduces perfusion of these vulnerable and metabolically active mTAL cells. The anaesthetist must prevent or attenuate postoperative renal dysfunction by identifying high-risk patients preoperatively, optimizing intravascular volume status and cardiac output in the perioperative period, as well as responding appropriately to hypoperfusion states. Therapeutic implications relate to this pathophysiological sequence and several physiological and pharmacological considerations are discussed.

Pharmacology and therapeutic use of low-dose dopamine

The renal pharmacologic effects of intravenous dopamine in doses of 0.5-3.0 micrograms/kg/min include increases in renal blood flow, glomerular filtration rate, solute excretion, and urine flow. Clinical studies revealed that low-dose dopamine can reverse oliguria, but these studies were poorly controlled, were confounded by the use of other diuretics, had small patient populations, and often did not evaluate mortality or long-term renal function. When used in low doses, side effects are rarely seen. Because of dopamine's effect on hepatic and renal function, changes in drug clearance may occur. Low-dose dopamine may be considered in the early course of oliguric patients; however, specific advantages over other diuretic therapy have not been established.

Acute renal failure in the surgical patient: initial diagnosis and treatment

Three categories of acute renal failure have been identified: prerenal, postrenal, and renal. Prerenal failure results from decreased perfusion of the kidney and postrenal failure from obstruction distal to the nephron; renal failure, in the surgical setting, usually represents acute tubular necrosis. A rational approach to the diagnosis of acute renal failure is outlined, and the treatment of acute tubular necrosis is discussed. High-risk factors are identified, and the importance of maintaining intravascular volume to prevent acute renal failure is stressed, since the mortality rate may approach 50% in patients in whom this perioperative complication develops.

Prostaglandin E1 and survival in patients with the adult respiratory distress syndrome. A prospective trial

A 7-day infusion of prostaglandin E1 (PGE1), an immunomodulator, was evaluated in a prospective, randomized, placebo-controlled, double-blinded trial in surgical patients with the adult respiratory distress syndrome (ARDS). The drug seemed to improve pulmonary function--only two PGE1 patients died with severe pulmonary failure compared with nine placebo patients (p = 0.01). Survival at 30 days after the end of the infusion--the predetermined end point of the study--was significantly better in the patients given PGE1 (p = 0.03), with 15 of 21 PGE1 patients (71%) alive at this time compared with seven of 20 placebo patients (35%). Improvement in overall survival in the PGE1 patients did not reach statistical significance (p = 0.08). Overall survival in patients initially free of severe organ failure, however, was significantly better in the PGE1 patients (p = 0.03). Of the six PGE1 patients free of severe organ failure at time of entry, all survived to leave the hospital; of the 10 placebo patients initially free of severe organ failure, four survived. The drug had no serious side effects and did not potentiate susceptibility to infection. PGE1 is a promising agent for the treatment of ARDS.

Acute renal failure in rats. Interaction between a contrast medium and renal arterial occlusion

Acute renal failure is a serious complication of reconstructive aortoiliac surgery. The question was raised whether its etiology includes interaction between preoperative angiographic contrast medium and intra-operative clamping of the renal arteries. Renal arteries of 180 rats were bilaterally clamped 10 to 120 min and serum urea was determined from 3 h to 7 days later. In 35 rats 40 min clamping alone produced an increase in urea reaching a maximum 1 day later (median increase 70%). In 3 groups of 12 rats intravenous injection of the contrast medium metrizoate alone in doses 1, 2 and 3 g I/kg body-weight produced no significant increase in urea. Intravenous injection of the same doses to 3 groups of 10 rats each followed 1 h later by renal arterial occlusion for 40 min produced median urea increases one day later of 110, 130 and 170 per cent, respectively, in the 3 groups. The increase was higher than that produced by contrast medium alone (p less than 0.01) or by renal artery clamping alone (p less than 0.05) indicating a potentiation of transient renal failure by the combination of contrast medium and renal arterial clamping.