Continuous renal replacement therapies: an update

Continuous renal replacement modalities have found widespread use and acceptance over the last decade. The various modalities differ in the kind of access (arteriovenous v venovenous); in the application of convective clearance (continuous hemofiltration), diffusive clearance (continuous hemodialysis), or a combination of both (continuous hemodiafiltration); and in the location where the replacement fluid enters the circuit (predilution v postdilution). Continuous therapies incorporate several advantages, such as improved hemodynamic stability, the possibility for unlimited alimentation, optimal fluid balance, and gradual urea removal without fluctuations. However, it has not yet been shown whether these advantages have a significant impact on outcome and prognosis, the ultimate measure of treatment efficiency. Major disadvantages of continuous therapies are the ongoing necessity for continuous anticoagulation, immobilization of the patient, and possible side effects from lactate-containing replacement fluid or dialysate. Continuous renal replacement procedures have certainly made the management of critically ill patients easier. In particular, oligoanuric patients with diuretic resistant volume overload and hemodynamically unstable patients with acute renal failure and concomitant sepsis or multiorgan failure appear to benefit most from continuous treatment. The role of continuous hemofiltration as a method of removing serum cytokines in septic patients without renal failure is still controversial and needs further clinical assessment. Due to slow efficacy, continuous renal replacement is indicated only in rare circumstances for intoxication; this therapy also is of rather limited use in severe hyperkalemia or acidosis. Noncritically ill patients with uncomplicated renal failure (eg, due to the use of dye or antibiotics) should be treated with intermittent hemodialysis or peritoneal dialysis. Furthermore, intermittent hemodialysis is preferable in patients with hemorrhagic diathesis because it can be easily performed without anticoagulants.     

Lead and the kidney: nephropathy, hypertension, and gout

Lead intoxication in human beings has been documented since the second century B.C. Renal disease, hypertension, and gout have all been linked to lead by strong circumstantial evidence. Both acute and chronic nephropathy can occur as a result of lead poisoning. Acute renal failure develops following acute lead intoxication and is often associated with gastrointestinal, neurologic, and hematologic disorders. Both blood and urinary laboratory abnormalities are associated with acute intoxication and are often diagnostic. Chronic lead nephropathy, a chronic tubulointerstitial nephritis on biopsy, occurs in the setting of long-term lead exposure and is often associated with hypertension and gout. Diagnosis of chronic lead nephropathy is more difficult since the laboratory abnormalities seen with acute lead intoxication are not present with chronic lead exposure. The typical clinical picture and the exclusion of other causes of renal disease allow the diagnosis of chronic lead nephropathy to be made. Evaluation of lead stores by either the calcium disodium edetate (EDTA) mobilization test or K-x-ray fluorescence are helpful in clinching the diagnosis. Treatment with EDTA lead mobilization is effective for acute lead poisoning while avoidance of further lead exposure prevents recurrence of lead intoxication. Treatment of chronic lead nephropathy with EDTA lead mobilization is useful if renal failure is modest; however, EDTA mobilization is of no benefit in patients with more severe renal insufficiency.     

Mannital induced acute renal failure

14 cases of mannitol-induced acute renal failure were reported. The dosage of mannitol used varied widely. In all cases serum Na+, HCO3- were decreased, K+ and BUN increased significantly. Serum osmolality was measured in 5 cases. The osmolal gap was increased greatly, 77.4mOsm/kg. H2O in average. The increase of osmolal gap may play an important role in acute renal failure by causing intensive renal vasocontraction. Monitoring of serum osmolality or osmolal gap can help to prevent mannitol intoxication. The decrease of serum Na+ may be a warning sign of increased osmolal gap. Hemodialysis is the best way for the treatment of mannitol-induced acute renal failure.     

Treatment of acute renal failure

Acute renal failure is a life threatening illness whose mortality has remained high since the introduction of hemodialysis 25 years ago, despite advances in supportive care. Acute renal failure is an extremely morbid and costly disorder with a significant proportion of patients progressing to end-stage renal disease requiring dialysis. To the nephrologist, acute renal failure remains an extremely frustrating disease, because the pathophysiology is not well understood and the limited therapeutic options force the nephrologist to sit on the sidelines and wait for renal function to return. For example, dialysis remains the only FDA-approved treatment for acute renal failure, but dialysis may also cause renal injury that prolongs renal failure. The purpose of this perspective is to understand the results of the recent, largely negative, clinical trials in view of recent advances in the epidemiology of ARF. This review will also discuss diagnostic tools, strategies for improved design of clinical trials, and other therapeutic interventions that will be needed to properly treat acute renal failure in the 21st century.     

Acute venous hemodialysis using the unipuncture apparatus

Hemodialysis is a well recognized treatment modality for the support of patients with acute renal failure. In such patients, rapid access to the circulation for hemodialysis is important. For those patients with self-limited acute renal failure in whom recovery is expected, a rapid means of gaining temporary access to the circulation would be particularly desirable. The Seldinger technic for femoral vein catheterization and the use of the unipuncture dialysis apparatus have been combined to meet this requirement. The efficiency of unipuncture dialysis through a single femoral catheter compares favorably with the efficiency of dialysis by the standard two catheter technic.     

Evidence from desensitization studies for distinct receptors for ATP and UTP on the rat superior cervical ganglion

A 44-year-old woman with scleroderma and Sj?gren's syndrome developed altered consciousness, acute renal failure, and rhabdomyolysis. She had no history of trauma, seizures, alcohol abuse, hyperthermia, or other possible causative factors for rhabdomyolysis. A high serum salicylate level indicated a diagnosis of salicylate intoxication. Medical history after recovery revealed chronic salicylate ingestion for severe headaches. This is possibly the first reported case of rhabdomyolysis caused by chronic salicylate intoxication. Continuous hemodiafiltration early in hospitalization was an effective treatment.     

Can fingernail creatinine concentrations be used to predict duration of azotemia?

Clinical use of fingernail creatinine estimation to predict duration of azotemia is yet to be validated. We studied the fingernail creatinine concentrations in 48 subjects: seven controls, nine with acute renal failure, five with rapidly progressive glomerulonephritis, 12 with chronic renal failure and 15 with end-stage renal failure on maintenance hemodialysis. The creatinine concentration in aqueous eluates of powdered nail clippings was determined by the alkaline picrate reaction. The mean fingernail creatinine concentration was significantly higher in patients with chronic renal failure (93.7 +/- 83.7 micrograms/g) and end-stage renal disease on maintenance hemodialysis (118.4 +/- 46.8 micrograms/g) as compared to those with acute renal failure (36.6 +/- 23.7 micrograms/g) and rapidly progressive glomerulonephritis (35.8 +/- 20.6 micrograms/g). The creatinine concentrations did not differ significantly between normal subjects (27.2 +/- 28.7 micrograms/g) and those with acute renal failure and rapidly progressive glomerulonephritis. However because of large variability in the values of fingernail creatinine concentrations within each group, the test lacked specificity. Therefore, this investigation is an unreliable indicator of duration of azotemia in individual patients and is not likely to be of much clinical use.     

Acute renal failure--etiologic and therapeutic considerations. A five-year experience at a single institution

In the present study we highlight the epidemiology, etiologic spectrum, and evaluation of ARF in adults. We then expand on the pathophysiologic mechanisms of renal failure and discuss the rationale for current therapeutic strategies in ARF patients. A total of 79 patients (45 male, female 34), aged 18-75 years (median age 51.2 +/- 17.7 years) with acute renal failure were studied in 5 years (January 1990 through October 1995). Emergency hemodialysis sessions following an acute anuric episode were instituted in 39 cases (49.3% of all patients). The median number of hemodialysis procedures per patient treated at our institution was 3.2 +/- 1.9. The total number of acute interstitial nephritis-associated ARF was 40. In 30 of them (75%) the acute renal insult included a combination of several therapeutic antimicrobial agents, in 2 cases (5%) ARF followed the administration of nonsteroidal anti-inflammatory drugs, in 1 (2.5%) it resulted from a combined therapeutic regimen and in the remaining 5 (12.5%) from the application of a single drug. Acute interstitial nephritis developed in 2 patients following a viral infection. In the hemodialysis-treated ARF group 12 patients (29.77%) had interstitial nephritis and 2 patients (5.13%) presented with renal impairment for an unspecified period of time preceding the development of overt ARF. In a subset of this group of patients, ARF occurred in 7 patients (17.95%) following an urologic intervention, in 8 patients (20.51%) as a consequence of thermal or mechanical trauma or intoxication and in 3 cases (7.69%) it resulted from fever of unknown origin. Three patients with postoperative peritonitis and 4 other (10.26%) with postoperative complications were encountered in our series. No cases of septic abortion-related or obstetric-related ARF were recorded. 92.3% of all hemodialysis-treated patients seen at our Institution had received a combination of antibiotics and only 2 patients had been pre-treated with a single antimicrobial agent. Our results underscore the strong tendency towards diversity in the etiologic spectrum of clinical entities causing ARF and the increase in the number of acute interstitial nephritis. These factors highlight the importance of precise dosing and administration of drugs, especially antibiotics, as well as the duration of antibiotic treatment.     

Transient exercise-induced water intoxication and rhabdomyolysis

Water loading only rarely results in adverse effects due to the high efficiency of the kidney in excreting free water. However, when renal diluting ability is impaired, such as in inappropriate vasopressin secretion, water intoxication can occur in otherwise normal individuals. We report the case of a 19-year-old man with acute voluntary water intoxication following exercise, which resulted in a transient defect in renal diluting capability. Hyponatremia was further complicated by rhabdomyolysis. We review the literature regarding other cases of hyponatremia following excessive water intake, and discuss the possible association between hyponatremia and rhabdomyolysis. We conclude that monitoring of muscle enzymes is indicated in acute hyponatremia, to allow for timely intervention intended to prevent rhabdomyolysis-associated acute renal failure.     

Reversal of renal failure and paraplegia after thoracoabdominal aneurysm repair

Repair of ruptured thoracoabdominal aortic aneurysms is complicated by high rates of perioperative paraplegia, renal insufficiency, and mortality. This report describes a patient with a ruptured thoracoabdominal aortic aneurysm in whom preoperative acute renal failure was reversed with hemodialysis, aortic replacement, and renal revascularization. Prompt cerebrospinal fluid drainage reversed delayed-onset postoperative paraplegia and led to immediate, complete neurologic recovery.     

Double (fluorescent and spin) sensors for detection of reactive oxygen species in the thylakoid membrane

In this report the authors describe the use of continuous venovenous hemodialysis (CVVHD) in a medically unstable patient who suffered from a spontaneous cerebellar hemorrhage. Conventional dialysis techniques carry the risk of developing the dialysis disequilibrium syndrome (DDS) when performed in the presence of a variety of intracranial diseases. The CVVHD technique was used successfully in a morbidly obese, short-statured woman with a spontaneous hypertensive intraparenchymal cerebellar hemorrhage. The woman experienced acute renal failure several days after her hemorrhage and her general medical condition prevented her from undergoing surgical evacuation. The CVVHD did not result in elevations in intracranial pressure (ICP) and the patient made a full recovery from both acute renal failure and life-threatening posterior fossa hemorrhage. This case is noteworthy because of the absence of abnormally high ICP elevations or development of DDS in a patient with a large acute posterior fossa intraparenchymal brain hemorrhage and acute renal failure whose case was managed with CVVHD in the acute period.     

Digoxin-quinidine interaction in patients with renal failure

Investigations were performed in order to study whether or not quinidine would exert similar effects on the serum digoxin concentration in patients with renal failure as in normal subjects. Fourteen out of fifteen patients showed a significant increase of the serum digoxin level after four days of quinidine application. This indicates, that the quinidine effect is not solely caused by a decrease of the renal digoxin clearance, although nine patients, not being hemodialysed, revealed a correlation between their creatinine clearance and the rise of the serum digoxin concentration after quinidine. As however, the patients on hemodialysis did not show higher digoxin levels than those treated conservatively, it is suggested that the degree of the uremic intoxication might be responsible for the observed correlation.     

Effect of manual segmental vibration on neuromuscular excitability

The prevalence of amphetamine abuse and the frequency of emergency department visits for amphetamine intoxication have increased dramatically worldwide. In this study, we retrospectively investigated the relationship between the prognostic features and clinical manifestations among patients admitted to the emergency department of a university hospital for acute methamphetamine intoxication during a 6-year period. Data collected included gender, age, route of abuse, time between drug exposure and arrival at the emergency department, estimated dose, signs and symptoms, laboratory values, and complications. Emergency therapy and cooling procedures were also recorded. After excluding 26 patients with multiple-drug intoxication, 18 patients (male-to-female ratio, 11:7) were include in the analysis. The mean age was 25.6 years. Thirteen patients survived and five died. Patients who died often presented with coma (80% vs 0%, p = 0.002), shock (60% vs 8%, p = 0.044), convulsions (100% vs 23%, p = 0.007), oliguria (80% vs 0%, p = 0.002), and high body temperature (41.4 +/- 0.5 degrees C vs 39.4 +/- 2.1 degrees C, p = 0.005). Furthermore, patients who died had significantly higher concentrations of blood urea nitrogen (8.7 +/- 2.1 vs 5.6 +/- 2.0 mmol/L, p = 0.01) and serum creatinine (212 +/- 71 vs 115 +/- 27 mumol/L, p = 0.033), and lower values of arterial pH (7.12 +/- 0.12 vs 7.34 +/- 0.10, p = 0.03), than those who survived. In the fatality group, the most common complication was rhabdomyolysis with acute renal failure (5 of 5); multiple organ failure resembling that from heatstroke was the leading cause of death from acute methamphetamine intoxication. In conclusion, the adverse prognostic features in patients with acute methamphetamine intoxication include coma, shock, convulsion, oliguria, and high core temperature. Acidosis, volume depletion, and ischemic renal damage were potential risk factors for development of acute renal failure in these patients.     

Acute renal failure. Community hospital experience with hemodialysis as intensive care adjunct

A 3-year experience with 50 acute renal failure patients managed by hemodialysis in a 417-bed community hospital is reviewed. The 58% survival rate was better than that reported in other recent series. Possible reasons for our favorable mortality experience include: (1) Hemodialysis was performed within the ICU facility by the ICU staff. Continuity of total care was thereby maintained and hemodialysis problems, such as maintenance of circulating volume, were managed in the context of continued assessment of the patient's cardiopulmonary status. (2) In contrast to previous reports, the presence of sepsis did not influence recovery rates from acute renal failure. Early administration of specific antibiotics, mainly gentamicin, rapid drainage of abdominal abscesses, and early and frequent dialysis were all utilized in spetic patients and may have contributed to their high recovery rate. (3) The use of agressive dialysis may also have lessened other uremic complications, notably gastrointestinal bleeding. Our dialysis organization and procedures are described.     

Dialysis in the treatment of renal failure in patients with liver disease

The value and effects of treating renal failure by dialysis are analyzed in a series of 84 patients with various types of liver disease. Although none of the 25 patients with cirrhosis survived, six of 50 with fulminant hepatic failure recovered completely as did seven of nine patients with renal failure secondary to extrahepatic biliary tract obstruction or with liver and renal damage following episodes of severe hypotension. Dialysis was required for seven weeks before diuresis occurred in one patient in the latter group. Both peritoneal and hemodialysis satisfactorily controlled plasma urea and creatinine levels, except in patients with fulminant hepatic failure in whom this was only achieved by hemodialysis. Complications of dialysis were most common in patients with cirrhosis and fulminant hepatic failure and included hypotension, gastrointestinal bleeding, and intraperitoneal sepsis. Overall, the results show that dialysis is only worth attempting in those patients in whom recovery of the underlying liver lesion is possible, and even then treatment for prolonged periods may be necessary.     

Seasonal variation of neuropeptide Y actions on growth hormone and gonadotropin-II secretion in the goldfish: effects of sex steroids

Tumor lysis syndrome is a critical illness characterized by massive tumor cell death leading to severe hyperuricemia, hyperphosphatemia, hyperkalemia, hypocalcemia, and acute renal failure in patients with rapidly growing cancers (especially Burkitt's lymphomas with extensive abdominal bulk). It may be preventable with allopurinol therapy combined with aggressive intravenous fluid therapy aimed at establishing an ongoing alkaline diuresis. In most cases renal failure is completely reversible; however, fatal hyperkalemia and volume overload may develop. Therefore, aggressive management with hemodialysis often is necessary to maintain life support while tumor burden is controlled with cytoreductive therapy. Early recognition and management by a team approach in the intensive care unit where careful monitoring is available serves to forestall severe renal failure, thereby improving short-term prognosis in susceptible patients.     

Peritoneal dialysis. Current status

Peritoneal dialysis has a definite role in the treatment of acute or chronic renal failure and certain fluid and electrolyte disturbances. Its major advantages are simplicity and availability. On the other hand, it is less effective and causes more patient discomfort than hemodialysis. Many factors enter into the decision to use one method of dialysis or the other, and the two should be considered complementary. The numerous complications that may occur during peritoneal dialysis can be avoided by careful attention to technical details. With the recent development of indwelling catheters and automatic cycling devices, long-term peritoneal dialysis is being used increasingly and successfully in the home, particularly in patients for whom home hemodialysis is difficult or inappropriate.     

Plasma mevalonate concentrations in uremic patients

Mevalonic acid (mevalonate or MVA), is an obligate precursor in the biosynthetic pathway of cholesterol. It is partially metabolized by the kidneys and its plasma concentrations are an index of endogenous cholesterol synthesis. The aim of the present study was to evaluate plasma MVA concentrations in uremic patients with different degrees of chronic renal failure (CRF; group A), and the effects of a single hemodialysis treatment on plasma MVA in a group of patients with end-stage renal disease (ESRD; group B). CRF patients exhibited a higher mean basal mevalonate concentration (13.3 +/- 6.5 ng/ml) than control subjects (4.68 +/- 1.32 ng/ml; P < 0.001). A statistically significant direct correlation was evident in CRF patients between mevalonate and creatinine plasma levels (r = 0.86; P < 0.001). A single hemodialysis treatment was associated with a significant reduction of plasma mevalonate concentrations four hours after the hemodialysis session (-57%; P < 0.001) and an increase up to the basal values 24 hours after the end of the treatment. In conclusion, our results demonstrated: (i) higher plasma MVA concentrations in patients with decreased renal function; (ii) a direct relationship between plasma MVA levels and the degree of kidney failure as expressed by creatinine plasma concentrations; and (iii) a clear cut reduction of elevated plasma MVA levels after a single hemodialysis treatment.