Renal replacement therapy for severe acute renal failure

Acute renal failure (ARF) is a sentinel event that signals increased complexity and risk during the course of any general hospital admission. The initial diagnosis and specific treatment of the ARF already pose a daunting challenge, but the stakes are even higher when ARF is severe and renal replacement therapy (RRT) is needed. This paper addresses the onset and diagnosis of ARF only briefly and then turns to the specific choice and design of RRT modality that will optimize the ultimate outcome. Some guidelines are proposed since definitive standards for the treatment of severe ARF in critically ill patients are still evolving.

Estimating the impact of renal replacement therapy choice on outcome in severe acute renal failure

BACKGROUND

Mortality in severe acute renal failure (ARF) requiring renal replacement therapy (RRT) approximates 50% and varies with clinical severity. Continuous RRT (CRRT) has theoretical advantages over intermittent hemodialysis (IHD) for critical patients, but a survival advantage with CRRT is yet to be clearly demonstrated. To date, no prospective controlled trial has sufficiently answered this question, and the present prospective outcome study attempts to compare survival with CRRT versus that with IHD.

METHODS

Multivariable Cox-proportional hazards regression was used to analyze the impact of RRT modality choice (CRRT vs. IHD) on in-hospital and 100-day mortality among ARF patients receiving RRT during 2000 and 2001 at University of Michigan, using an "intent-to-treat" analysis adjusted for multiple comorbidity and severity factors.

RESULTS

Overall in-hospital mortality before adjustment was 52%. Triage to CRRT (vs IHD) was associated with higher severity and unadjusted relative rate (RR) of in-hospital death (RR = 1.62, p = 0.001, n = 383). Adjustment for comorbidity and severity of illness reduced the RR of death for patients triaged to CRRT and suggested a possible survival advantage (RR = 0.81, p = 0.32). Analysis restricted to patients in intensive care for more than five days who received at least 48 hours of total RRT, showed the RR of in-hospital mortality with CRRT to be nearly 45% lower than IHD (RR = 0.56, n = 222), a difference in RR that indicates a strong trend for in-hospital mortality with borderline statistical significance (p = 0.069). Analysis of 100-day mortality also suggested a potential survival advantage for CRRT in all cohorts, particularly among patients in intensive care for more than five days who received at least 48 h of RRT (RR = 0.60, p = 0.062, n = 222).

CONCLUSION

Applying the present methodology to outcomes at a single tertiary medical center, CRRT may appear to afford a survival advantage for patients with severe ARF treated in the ICU. Unless and until a prospective controlled trial is realized, the present data suggest potential survival advantages of CRRT and support broader application of CRRT among such critically ill patients.

Comparison of 3 vancomycin dosage regimens during hemodialysis with cellulose triacetate dialyzers: post-dialysis versus intradialytic administration

AIMS

Traditionally, vancomycin is administered following dialysis to minimize drug loss when high-flux membranes are employed. Unfortunately, this approach is extremely inconvenient for patients and staff, requiring the patients to remain in the unit for at least 1 hour following dialysis. This study was designed to evaluate the feasibility of administering vancomycin during hemodialysis. Specifically, this study was designed to compare the pharmacokinetics of vancomycin when administered during the last 1-2 hours of dialysis (i.e. intra-dialytic administration) to that administered after completion of dialysis.

MATERIALS AND METHODS

In a randomized, 3-way crossover trial, the pharmacokinetics of vancomycin were evaluated in 9 hemodialysis patients, comparing vancomycin 15 mg/kg following dialysis (Phase I), vancomycin 15 mg/kg during the last hour of hemodialysis (Phase II) or vancomycin 30 mg/kg during the last 2 hours of hemodialysis (Phase III). Vancomycin plasma concentrations were obtained over an 8-day period and subsequent comparisons between the treatment approaches were made with paired t-tests or ANOVA, as appropriate. Dialysate vancomycin concentrations determined on Day 1 and Day 3 of Phases II and III were used to calculate the fraction of vancomycin dose removed, and were compared to plasma data using paired t-tests.

RESULTS

Vancomycin was significantly removed (33.4 to 39.5%) during a 3- to 4-hour high-flux dialysis session occurring on Day 3 after vancomycin administration. Mean serum concentrations immediately following intradialytic vancomycin administration of 15 mg/kg over the last hour of dialysis or 30 mg/kg over the last 2 hours of dialysis were initially high (77.7 and 95.5 mcg/ml respectively), but fell to 25.9 and 40.5 mcg/ml, respectively, by 4 hours post-dialysis. Predialysis concentrations on Days 3, 5 and 8 were similar for vancomycin 30 mg/kg administered over the last 2 hours of dialysis as compared with a 15 mg/kg dose given after dialysis. Vancomycin 15 mg/kg over the last hour of dialysis resulted in significantly lower subsequent predialysis concentrations than the other dosing schemes.

CONCLUSIONS

Vancomycin administration of 30 mg/kg over the last 2 hours of dialysis achieves serum concentrations similar to conventional dosing of 15 mg/kg after dialysis and would allow dosing on a weekly basis.

Analysis of variable flow Doppler hemodialysis access flow measurements and comparison with ultrasound dilution

The variable flow (VF) Doppler method determines access blood flow from the pump speed-induced change in Doppler signal between the arterial and venous needles. This study evaluated 35 patients in two analyses to assess VF Doppler measurement reproducibility (54 paired measurements) and compared VF Doppler and ultrasound dilution flow measurements (24 paired measurements). VF Doppler measurement variations were 4% for access flow less than 800 mL/min (n = 17), 6% for access flow of 801 to 1,600 mL/min (n = 22), and 11% for access flow greater than 1,600 mL/min (n = 15). The mean measurement coefficient of variation was 7% for VF Doppler compared with 5% for ultrasound dilution. Correlation coefficients (r) between VF Doppler and ultrasound dilution access flow measurements were 0.79 (n = 24; P < 0.0001), 0.84 for access flow less than 2,000 mL/min (n = 20; P < 0.0001), and 0.91 for access flow less than 1,600 mL/min (n = 18, P < 0.0001). VF Doppler measurements using indicated versus measured pump flow rates correlated highly (r = 0.99; P < 0.0001). VF Doppler therefore yields reproducible access volume flow measurements that correlate with ultrasound dilution measurements. The VF Doppler method is dependent on the pump-induced change in access Doppler signal and therefore is inherently most accurate and reproducible at lower access blood flow rates. This method appears capable of determining access flow rates in the clinically useful range.

Exit-site and catheter care: review of important issues

This brief review addresses the impact that several important aspects of catheter technology and exit-site care have on catheter-related infections and catheter longevity. The discussion includes exit-site microbiology, catheter configuration, exit-site care, and catheter salvage, following which a summary of recommendations is presented.

The use of peritoneal dialysis in special situations

This brief review outlines several situations in which peritoneal dialysis (PD) can be used to address clinical situations that are out of the ordinary for end-stage renal disease (ESRD). For example, PD methodology can be used not only to treat ESRD patients with difficult psychosocial problems that obviate other dialysis options, but also to control ascites accumulation in patients with liver failure, to treat congestive heart failure in azotemic patients with progressive cardiomyopathy, to administer systemic medication via the peritoneal cavity, and to provide additional clearance in demanding circumstances. In discussing these unusual applications for PD, we open the door to extending the indications for PD to a broader spectrum of clinical problems.

Variable flow Doppler for hemodialysis access evaluation: theory and clinical feasibility

Access thrombosis remains an enormous problem for patients on hemodialysis. Current evidence suggests that decreasing access blood flow rate is an important predictor of future access thrombosis and failure. This article describes a method for determining access volume flow and detecting access pathology. The Doppler ultrasound signal downstream from the arterial needle as a function of the variable hemodialysis blood pump flow rate, is used to determine access blood flow. By using this variable flow (VF) Doppler technique compared with duplex volume flow estimates measured in 18 accesses (16 patients with 12 polytetrafluorethylene [PTFE] grafts and 6 autogenous fistulas), the results showed a correlation of 0.83 (p < 0.0001) between these methods. In grafts with lower blood flow rates, aberrant flow patterns were observed, including stagnant or reversed flow during diastole while forward flow was maintained during systole. When reversed diastolic flow was severe, it was accompanied by access recirculation. In conclusion, we report the theory and clinical feasibility of determining access blood flow by using a VF Doppler technique. Measurements are made without the need to determine the access cross sectional area required for duplex volume flow calculations and without the need to reverse the lines required for various indicator dilution techniques. Important information is also obtained about aberrant flow patterns in patients at risk of access failure.

Comparing continuous hemofiltration with hemodialysis in patients with severe acute renal failure

Continuous venovenous hemofiltration (CVVH) or CVVH with additional diffusive dialysis (CVVH-D) has theoretical advantages in treating severe acute renal failure (ARF), but no prospective clinical trials or restrospective comparison studies have clearly shown its superiority over intermittent hemodialysis (HD). To evaluate this question, all 349 adult patients with ARF receiving renal replacement therapy (RRT) at our medical center during 1995 and 1996 were analyzed using multivariate Cox proportional hazards methods. Initial univariate analysis showed the odds of death when receiving initial CVVH to be more than twice those when receiving initial HD (risk for death, 2.03; P < 0.01). Progressive exclusion of patients in whom the RRT modality might not be open to choice and the risk for death was very high (systolic blood pressure < 90 mm Hg; total bilirubin level > 15 mg/dL; or total RRT < 48 hours) for total RRT left 227 patients in whom the risk for death was 1.09 (95% confidence interval [CI], 0.67 to 1.80; P = 0.72) for initial CVVH, virtually equivalent to the risk for initial HD. Comorbid indicators significantly associated with death or failure to recover renal function included: older age; medical rather than surgical diagnosis; preexisting infection or trauma and liver disease as primary diagnoses; and abnormal bilirubin level or vital signs at initiation of RRT. These results show that the high crude mortality rate of patients undergoing CVVH was related to severity of illness and not the treatment choice itself. With the addition of more inclusive comorbidity data and a broader spectrum of interim outcomes, this type of analysis is a practical alternative to what would almost assuredly be a cumbersome and costly prospective, controlled trial comparing traditional HD with CVVH.

Preparation of ethanol-enriched, bicarbonate-based hemodialysates

We describe a method to produce bicarbonate-based dialysates containing approximately 100 mg/dl ethanol by introducing the alcohol into one of the dialysate concentrate solutions geared for the production of bicarbonate-based dialysates.

Simultaneous catheter removal and replacement in peritoneal dialysis infections: update and current recommendations

Problematic peritoneal dialysis infection is a major cause of catheter loss and interruption of peritoneal dialysis (PD) therapy. In selected instances, problematic infection can be successfully treated by removing and replacing the catheter while continuing with PD. Accumulated experience has helped to define the circumstances under which a removal/replacement procedure is likely to be safe and under which complications are likely to arise. It appears that simultaneous removal and replacement can be expected to succeed when problematic infection is associated with tunnel infection, with recurring peritonitis repetitively culturing the same organism but clearing between episodes, and with gram-positive organisms. Success is less likely in the presence of ongoing inflammation, of active infection, of gram-negative or fungal organisms, or of any evidence of intra-abdominal adhesions. We review the literature on which these criteria are based and conclude with updated recommendations.

Peer resource consulting: redesigning a new future

The current case describes a young woman with diabetes mellitus who developed end-stage renal disease (ESRD) and many other devastating complications related to her primary illness. Her experience illustrates many ways in which complicated illness can interrupt life's plans, dashing any dreams that she or her family might have for the future. Yet her story also illustrates the important role that a trained Peer Resource Consultant (PRC) can play in helping to better understand chronic illness, face and grieve losses, and even design new plans and create new dreams for the future. The discussion that follows includes several perspectives that offer poignant insight into the difficult situations characterized by the young diabetic with ESRD.

Central venous catheters for maintenance hemodialysis: a cautionary approach

There is an increasing trend toward the use of indwelling central venous catheters (CVC) for maintenance hemodialysis. Although such devices are necessary in some problematic cases, the general use of CVC is worrisome. Not only may CVC prejudice the ultimate success of future permanent vascular access, but CVC also may be associated with reduced dialysis delivery and with several important complications. This review summarizes recent developments in catheter design, placement techniques, maintenance of the indwelling catheter, and complications of CVC use. Based on cumulated experience, a judicious position is taken that recognizes the place of CVC among the various access options but that favors permanent vascular access whenever feasible.

Racial group differences in plasma concentrations of antioxidant vitamins and carotenoids in hemodialysis patients

Approximately 50% of the mortality in hemodialysis patients is due to cardiovascular disease. Antioxidant vitamins and carotenoids may be protective because oxidation of low-density lipoproteins appears to be a necessary prerequisite for the development of atherogenesis, and hemodialysis itself may stimulate the generation of oxygen reactive species. African Americans comprise a substantial proportion of dialysis patients because they have higher rates of hypertension, glomerulonephritis, and diabetic end-stage renal disease than do whites. The purpose of this cross-sectional study was to determine the plasma concentrations of antioxidant vitamins and carotenoids in hemodialysis patients and to investigate whether differences in these concentrations in the major racial or ethnic groups exist. Plasma concentrations of alpha- and gamma-tocopherol, carotenoids, and retinol were measured with HPLC and plasma vitamin C was measured with a spectrophotometric method in 109 white and African American hemodialysis patients. Dietary intakes of selected micronutrients were also compared by using data from a food-frequency questionnaire. Overall, plasma vitamin C and alpha-tocopherol concentrations were comparable but plasma carotenoid concentrations were lower than those reported for other populations. African American patients had significantly higher mean plasma concentrations of retinol (P < 0.04), lutein (P < 0.02), and total carotenoids minus lycopene (P < 0.04); whites had significantly higher mean plasma concentrations of alpha-tocopherol (P < 0.02), independent of age and plasma lipid concentrations. Diabetes comorbidity had an independent negative association with plasma beta-carotene concentration but was not associated with other measures.

Withdrawal from dialysis: a review with an emphasis on the black experience

Withdrawal from dialysis has been shown to be a common occurrence in treated end-stage renal disease. Interestingly, there have been several reports documenting that blacks withdraw from dialysis one half to one third the rate of whites. There has been little research into the reasons for this marked discrepancy. This article reviews the existing literature on the different rates of withdrawal in blacks compared with whites. It then draws on a broad range of literature, including sociology, psychiatry, and anthropology, to propose possible reasons for the differences. From this review, it would seem that both medical and cultural factors play important roles in the decisions about withdrawal, but that cultural beliefs and attitudes are more important. More research is needed in both the medical and cultural aspects of rates of withdrawal to help explain the observed differences in blacks compared with whites.

Redefining the incidence of clinically detectable atheroembolism

BACKGROUND AND OBJECTIVES

Atheroembolism, caused by peripheral embolization of small cholesterol crystals that fracture off of ruptured atherosclerotic plaques in the major vessels, leads to multifocal ischemic lesions and progressive tissue loss. The end result is often ischemic injury in the skin, kidney, brain, myocardium, and intestine, but any organ distal to the culprit lesion may be affected. The precise incidence of this serious clinical syndrome has been difficult to ascertain from the available literature, but it appears to be much more common than has been assumed. The objective of the present study is to clarify the incidence of atheroembolism among inpatients in an acute hospital setting.

PATIENTS AND METHODS

We surveyed inpatient nephrology consultations during a 7-month period from January through July 1994. From a pool of 402 consultation charts, 99 were identified with two or more substantive risk factors for atheroembolism. The records of 85 of these patients were available for careful review. More than 300 additional patients were found to have ICD-9 discharge codes for other vascular conditions, but we were unable to confirm that any of these were in fact cases of atheroembolism, since there is no specific ICD-9 discharge code for this entity. In the 85 cases reviewed, a diagnosis of atheroembolism was made only if the patient had identifiable substantive risk factors, suggestive physical findings, and supporting laboratory results.

RESULTS

Eleven of the 85 surveyed records documented strong evidence supporting a "probable" diagnosis of atheroembolism. Tissue was examined in 4 of these 11, resulting in definitive histologic confirmation in 3. Another 5 of the 85 surveyed records were "suggestive" of atheroembolism. Altogether, atheroembolism was a likely diagnosis in a total of 16 cases during this 7-month period, or 1 case in every 2 weeks. These cases comprised 19% of nephrology consultations in which 2 or more risk factors were present, or 4% or all nephrology consultations. The patients' records confirmed the serious implications of clinically detectable atheroembolism. Several patients underwent lower extremity amputation, nearly half required acute or chronic dialysis, and more than half died within several months of diagnosis

CONCLUSIONS

The present study suggests that at least 4% of all inpatient nephrology consultations, representing approximately 5% to 10% of the acute renal failure encountered, involve clinically significant atheroembolism. Patients with atheroembolism appear at a rate of at least 1 case every 2 weeks. They often have identifiable substantive risk factors at initial consultation, and probably represent only the most severe cases of atheroembolism. In view of the serious implications of this basically untreatable syndrome, heightened awareness and preventive maneuvers in the population at risk are essential.

Long-term intraperitoneal deferoxamine for hemochromatosis

Intraperitoneal deferoxamine is a well established treatment for aluminum accumulation syndrome in patients with end-stage renal disease receiving peritoneal dialysis, but the use of intraperitoneal deferoxamine has not been described outside of the setting of chronic renal failure. We present here a case of secondary hemochromatosis, complicated by cirrhosis and cardiomyopathy, in which a chronic peritoneal dialysis catheter was used both to treat ascites and to deliver parenteral deferoxamine for iron overload. Daily urinary iron excretion was similar to that achieved when using standard routes of deferoxamine administration. Over a 2-year period, reversal of both the biochemical indicators and the clinical manifestations of iron overload was accomplished.

Influence of cellulose triacetate hemodialyzers on vancomycin pharmacokinetics

This study was designed to evaluate the pharmacokinetics of vancomycin during hemodialysis with cellulose triacetate (CT) high-flux dialyzers and to assess the influence of membrane surface area on intradialytic clearance. In a randomized crossover fashion, the pharmacokinetics of vancomycin were evaluated during dialysis with the CT 110 and CT 190 membranes. Six hemodialysis patients received 1 g of vancomycin immediately after the completion of a dialysis session, and subsequently, blood samples were obtained over a 5-day study period. On Day 3 subjects were dialyzed with CT 110 or CT 190 membranes. The mean intradialytic clearance of vancomycin was 56.7 +/- 7.5 and 100.70 +/- 10.7 mL/min with the CT 110 and CT 190 membranes, respectively (P < 0.05). Significant rebound in vancomycin serum concentrations occurred after dialysis; this rebound appeared to be complete 3 h postdialysis. On the basis of postrebound concentrations, the apparent percent removal of vancomycin was 23.6 +/- 1.2 and 25.2 +/- 8.6% for CT 110 and CT 190 membranes, respectively (not significant). Vancomycin is significantly cleared during dialysis with cellulose triacetate membranes, and its clearance is dependent on membrane surface area. Although a small supplemental dose of vancomycin could be administered after dialysis to replace drug lost during dialysis, it may be more efficient to give a larger dose of vancomycin after several dialysis periods. The determination of vancomycin removal can be used to estimate vancomycin serum concentrations as well as dosage requirements. This in conjunction with serum concentration monitoring can be used to optimize vancomycin dosing.

The option to withdraw from chronic dialysis treatment

This multidisciplinary discussion focuses on the case of a young diabetic woman who chose to stop chronic hemodialysis during a long and complicated illness. The perspective presented here include an academic lawyer's view of such medical decisions; a hospital chaplain's view of the religious framework for end-of-life situations; a clinical psychiatrist's considerations when consulted to evaluate patients in such straits; a transplant nurse's view of the opportunities for personal interaction that such clinical situations present; and a renal social worker's approach to chronic illness, advance directives, and death in the dialysis patient population. The discussion is intended to address objectively some important issues associated with death in this population, aimed at increasing our willingness to discuss these issues more openly with patients and with our colleagues.

Successful use of cuffed central venous hemodialysis catheters inserted percutaneously

Although endogenous fistulae and grafts are preferred for permanent hemodialysis access, central venous catheters are often required for varying intervals when creating permanent access is not feasible. The prospective experience with 118 catheters in over a 3.5-yr period is reported; 93 (79%) were placed by percutaneous techniques, and 25 (21%) were placed by operative techniques. Seventy seven catheters (65%) were placed in the subclavian vein, 36 (31%) were placed in the internal jugular vein (usually right side), and 5 (4%) were placed in the femoral vein. Early postplacement complications were infrequent. Catheter function at last local follow-up ranged from several days to nearly 2 yr, averaging approximately 3 mo, even though many patients returned to their referring centers with a functioning catheter after only a short follow-up. Actuarial survival for percutaneously placed catheters was approximately 60% at 6 mo and 30% at 12 mo. Catheter failure occurred in 36% of cases, equally divided between malfunction (thrombosis refractory to fibrinolysis, extrusion, kinking, or related event) and infection with septicemia requiring removal. Such failure was not more frequent after percutaneous placement than after operative placement. Failure due to mechanical malfunction, but not that due to infection, tended to be less frequent among catheters placed in the internal jugular vein than among catheters placed in the subclavian vein. Finally, infection with septicemia involved 22% of all catheters and occurred at an average cumulated rate of approximately one infection per patient-year. Coagulase-positive staphylococcus was the most common organism isolated.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful use of indwelling cuffed femoral vein catheters in ambulatory hemodialysis patients

Three hemodialysis patients with multiple upper extremity vascular access complications and central vein stenosis were treated for as long as 3 months using an indwelling femoral vein catheter having a buried felt cuff in its subcutaneous tunnel. Four catheters were placed in these three patients. In one case, initial failure due to poor flow and clotting occurred using a straight catheter with its tunnel crossing the inguinal ligament and exiting caudally on the anterior thigh. Otherwise, each patient had successful placement of a 180-degree, curved catheter that exited the femoral vein in the usual fashion but had a subcutaneous tunnel and skin exit pointing cephalad in the inferior portion of the right lower quadrant. The three successful devices functioned immediately after placement, having acceptable outflow pressures and recirculation values. One of three catheters was removed 3 weeks after placement when persisting infection was thought to reside on the device. No other bleeding, thromboembolic, or infectious complications occurred in these patients. In conclusion, short-term indwelling femoral vein access may be feasible in ambulatory hemodialysis patients with previous access difficulties that complicate temporary dialysis treatment.

Connective tissue activation. XXXVI. The origin, variety, distribution, and biologic fate of connective tissue activating peptide-III isoforms: characteristics in patients with rheumatic, renal, and arterial disease

OBJECTIVE

To determine the origin, distribution, and biologic fate of platelet-derived connective tissue activating peptide-III (CTAP-III), to define the relative amounts of the antigen forms (CTAP-III, beta-thromboglobulin [beta-TG], neutrophil activating peptide-2 [NAP-2]) in plasma of normal persons and those with rheumatic or end-stage renal disease, and to define the isoforms of CTAP-III in platelets, plasma, transudates, and tissue deposits.

METHODS

CTAP-III in plasma was measured by enzyme-linked immunosorbent assay, and growth promoting activity of CTAP-III isoforms was tested in synovial and peritoneal cell cultures by measuring increased synthesis of 14C-glycosaminoglycan (14C-GAG) and 3H-DNA. Isolated CTAP-III was characterized by Western blotting, microsequencing, and mass spectrometry.

RESULTS

CTAP-III was the primary isoform of this antigen family in normal platelets and platelet-rich plasma; beta-TG and NAP-2 accounted for < 1% of CTAP-III isoforms. Previously undescribed isoforms, i.e., CTAP-III des 1, des 1-2, des 1-3, and a phosphate adduct of CTAP-III, were observed in varying amounts. Elevated plasma levels of CTAP-III antigen were found in a substantial fraction of rheumatic disease patients: 24% of those with rheumatoid arthritis, 36% of those with systemic sclerosis, and 15% of those with systemic lupus erythematosus. All 10 patients with end-stage kidney disease had marked elevations of plasma CTAP-III levels, which stimulated DNA and GAG synthesis by peritoneal cells in culture. Only large isoforms (such as CTAP-III) were detected in venous plasma of normal subjects, rheumatic disease patients, and patients receiving long-term dialysis. Normal human spleen and kidney contained substantial (micrograms/gm) amounts of CTAP-III and traces of an isoform with the electrophoretic mobility of CTAP-III des 1-15/NAP-2. Liver, lung, and urine contained lesser (ng/gm) amounts of CTAP-III.

CONCLUSION

These data show that, among the 10 known isoforms, intact CTAP-III itself was the major circulating isoform (> 90%), and beta-TG was the most rare (0-1%). Deposition of CTAP-III in tissues, such as synovium, spleen, and kidney, is associated with partial processing to NAP-2-like isoforms and the potential to induce neutrophil and fibroblast activation in patients with rheumatic or end-stage renal disease.

Advance directives are associated with "good deaths" in chronic dialysis patients

The effect of prior advance directives (AD) on the outcome when chronic dialysis patients died was evaluated in a retrospective review of consecutive deaths over a period of more than 6 yr in a large academic dialysis center. Among 182 patients who died during the period under review, 74 (41%) had previously stated their AD verbally or in writing and the prevalence of AD was highest among patients with age-related or chronically debilitating diseases. Previous statement of AD was significantly more prevalent (P < 0.001) among patients who withdrew from treatment in reconciled fashion than among patients who died suddenly and unexpectedly or who died without a reconciled decision to forego life-sustaining intervention (e.g., dialysis, intubation, emergency surgery). Further analysis shows that patients stating prior AD and patients withdrawing from treatment were most often those who made their own medical decisions ("internal" locus of decision making), rather than relying on relatives or other agents ("external" locus), and tended to be those with a definite spouse or spouse-equivalent relationship. Finally, retrospective assessment suggests that cases in which patients stated prior AD and cases in which patients withdrew from treatment were associated more frequently with a favorable outcome. It was concluded that addressing AD before a medical crisis ensues may increase the likelihood of a "good death" when complications bring the course of chronic dialysis to termination.(ABSTRACT TRUNCATED AT 250 WORDS)

Complications of continuous ambulatory peritoneal dialysis: evaluation with CT peritoneography

OBJECTIVE

Patients on continuous ambulatory peritoneal dialysis are frequently referred for radiologic evaluation of complications related to the dialysis. We studied the value of CT peritoneography in evaluating these complications. CT peritoneography is a technique in which CT scans are obtained after dialysis fluid containing iodinated contrast material is infused into the peritoneal cavity through the dialysis catheter.

MATERIALS AND METHODS

Sixty consecutive CT studies performed on 48 patients during a 5-year period were retrospectively analyzed. In each case (with two exceptions), the patient had clinical findings suggesting a complication related to peritoneal dialysis. Each study was reviewed for evidence of dialysate leaks, hernias, unopacified fluid collections, and peritoneal adhesions. The patients' medical records also were reviewed to determine the resulting therapy and outcome.

RESULTS

Twenty-nine dialysate leaks were detected on 25 examinations: 15 were along the catheter tunnel, 10 were at the site of a previous surgical incision, two were at a previous catheter site, and two were from an undetermined site (catheter tunnel suspected in both cases). Loculated, unopacified peritoneal fluid collections were present on seven examinations. Adhesions limiting dialysate distribution were shown on five examinations. Five abdominal wall hernias and two inguinal hernias were detected. Overall, at least one abnormality related to continuous ambulatory peritoneal dialysis was shown on 40 (67%) of 60 studies. In 29 (73%) of these cases, clinical management was changed.

CONCLUSION

CT peritoneography is useful for evaluating complications commonly encountered in patients on continuous ambulatory peritoneal dialysis.

Unusual causes of peritonitis in patients undergoing continuous peritoneal dialysis with emphasis on Listeria monocytogenes

Peritonitis remains a significant cause of morbidity in ESRD patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Staphylococcus species, Streptococcus species, and less commonly, gram-negative rods comprise the majority of isolated organisms. Other organisms, including unusual bacteria, fungi, and mycobacteria, comprise 5% or less of cases. Many of the uncommon causes of CAPD peritonitis have been reviewed, with special emphasis on antimicrobial therapy and whether catheter removal was required. The presumed third case of CAPD-associated peritonitis caused by Listeria monocytogenes is also described. In contrast to two other reported cases, our patient was not overtly immunosuppressed. L. monocytogenes infection should therefore be considered in CAPD patients with gram-positive rod peritonitis, even if immunocompetence is presumed.

Pharmacokinetics of quinapril and its active metabolite quinaprilat during continuous ambulatory peritoneal dialysis

The pharmacokinetics of quinapril, a novel angiotensin converting enzyme (ACE) inhibitor, and its active metabolite, quinaprilat, were determined following a single 20-mg oral dose of quinapril in six patients with chronic renal failure maintained on continuous ambulatory peritoneal dialysis (CAPD). Overall, quinapril was well tolerated by these CAPD patients, with mild and transient side effects, not unexpected in this clinical setting, which included pruritus, headache, nausea, and cough. Blood pressure reduction was observed in four of six patients, with onset reliably two to four hours after dosing and duration up to 48 hours, associated with quinaprilat concentrations in plasma above 90 ng/mL for at least 33 hours postdose. Two patients experienced significant hypotension, systolic blood pressure below 90 mm Hg, which responded promptly to oral fluid administration and/or reduction in dialysate tonicity. The pharmacokinetic profile of quinapril in these CAPD patients was not significantly different from that previously observed in healthy subjects with normal renal function and in patients with moderate to severe renal dysfunction not yet requiring dialysis (RDND). The apparent elimination half-life of quinapril was approximately one hour, with negligible dialysate excretion. The pharmacokinetic profile of quinaprilat in these CAPD patients was similar to that previously observed in patients with RDND. The elimination half-life of quinaprilat was markedly prolonged when compared to that in healthy subjects and averaged 20 hours, with only a small amount of quinaprilat excreted in dialysate (mean = 2.6% of total dose).(ABSTRACT TRUNCATED AT 250 WORDS)

Serum guanidino compound levels and clearances in uremic patients treated with continuous ambulatory peritoneal dialysis

Guanidino compounds are increased in uremia and have been implicated as uremic toxins. The serum concentrations of 13 guanidino compounds and the clearances of 10 guanidino compounds were determined in 15 steady-state uremic patients treated with continuous ambulatory peritoneal dialysis. Guanidino compounds were determined using liquid cation-exchange chromatography with a sensitive fluorescence detection method. Standardized dialysis procedures were performed, including an overnight and a 3-hour dwell period. Guanidino compound levels did not significantly differ at the end of an overnight or a 3-hour exchange, indicating a steady-state blood chemistry for these substances in chronic ambulatory peritoneal dialysis. High levels were found for guanidinosuccinic acid, creatinine, guanidine and methylguanidine, while creatine and homoarginine levels were lower than in controls. Guanidinosuccinic acid, creatinine and methylguanidine reached levels associated with toxic effects in vitro. Significantly different clearances were found ranging from 4.02 +/- 1.08 ml/min for arginine to 7.94 +/- 2.76 ml/min for creatine during a 3-hour exchange.

Amelioration of chronic renal allograft dysfunction in cyclosporine-treated patients by addition of azathioprine

Management of chronic renal allograft dysfunction in cyclosporine-prednisone treated renal allograft recipients remains problematic. We therefore initiated a protocol of azathioprine addition (1.0-1.5 mg/kg/day) to ongoing CsA/Pred therapy. Three groups were treated. Group A (n = 21) had chronic progressive renal dysfunction (serum creatinine greater than or equal to 2.5 mg/dl or more than 15% above baseline) four or more months after transplantation. Group B (n = 8) had frequent or severe rejection episodes occurring despite adequate CsA levels. Group C (n = 7) had constitutional side effects of CsA with or without renal dysfunction persisting despite drug taper or financial difficulty in affording CsA. Aza was initiated 17.8 +/- 2.8 months after transplantation in group A, the mean serum creatinine having risen from 2.55 +/- 27 mg/dl to 3.04 +/- .20 mg/dl (P = .07) over the six months preceding Aza initiation, despite stable and low therapeutic range HPLC whole-blood CsA levels (118 +/- 10 ng/ml vs. 133 +/- 11 ng/ml, P = NS). Renal function declined at a rate of -0.20 +/- .06 Cr1/year in the six-month period before addition of Aza, and then improved at a rate of 0.09 +/- .04 Cr-1/year after addition of Aza (P = .002). These changes in renal function occurred without a decrease in CsA levels (118 +/- 10 six months before Aza vs. 126 +/- 26 six months after Aza, P = NS). In group B Aza was initiated at 58 +/- 8 days after transplantation when mean sCr was 3.56 +/- .29 mg/dl and mean CsA level was 222 +/- 17 ng/ml. At least follow-up 12.7 +/- 2.0 months after addition of Aza, all group B grafts were functioning, mean sCr was 2.69 +/- .31 mg/dl (P = .09 compared with baseline), and mean CsA level was 128 +/- 34 ng/ml (P = .07 compared with baseline). Group C patients had addition of Aza at 43 +/- 19 months after transplantation when mean sCr was 2.97 +/- .60 and mean CsA level was 125 +/- 30 ng/ml; addition of Aza had no influence on the rate of decline in renal function in this group. Of these 36 patients, 6 received therapy for acute rejection over the entire follow-up period of 12.3 +/- 1.4 months after addition of Aza; 4 of these retain graft function. Infectious complications consisted of 2 urinary tract infections, 1 bacterial pneumonia, and one case of otitis media.(ABSTRACT TRUNCATED AT 400 WORDS)

Epoprostenol (PGI2, prostacyclin) during high-risk hemodialysis: preventing further bleeding complications

The frequency of hemodialysis-associated hemorrhage was studied prospectively in two successive, parallel, heparin-controlled studies using epoprostenol (PGI2; average dose, 4.1 ng/kg.min) as the sole antithrombotic agent. Sixty-three patients with active or recently active bleeding underwent 163 hemodialysis treatments in each of which prospective bleeding risk was assessed. PGI2 was associated with up to 50% overall reduction in the frequency of bleeding, particularly in the highest risk circumstances. PGI2 also allowed successful completion of the full, prospectively prescribed hemodialysis time in the most treatments (82% versus 93% with heparin). Furthermore, the efficiency of hemodialysis using PGI2, as indicated by the reduction in concentration of blood urea nitrogen and serum creatinine, was equal to that using heparin, even though there was a tendency toward modest reduction in residual volume of the hollow fiber dialyzer and slightly more frequent early termination of treatment from dialyzer clotting with PGI2. No severe vasodilatory side effects of PGI2 were observed during these studies. Hypotension was equally frequent during hemodialysis with heparin as with PGI2. The current results suggest that PGI2 should be considered as a substitute for heparin during high-risk hemodialysis because PGI2 may reduce the incidence of dialysis-associated bleeding without severe adverse side effects.

Atrial natriuretic hormone secretion in patients with renal failure

To study the effects of volume overload and renal failure on plasma levels of immunoreactive atrial natriuretic hormone (IR-ANH), we measured levels of this hormone in normal subjects, in patients with advanced chronic renal failure (CRF) with and without clinically evident volume overload, and in patients with end-stage renal disease (ESRD) treated with chronic hemodialysis. The levels were 13 +/- 2 pmol/l in normal volunteers, 77 +/- 24 pmol/l in patients with CRF without volume overload, and 219 +/- 50 pmol/l in patients with CRF and clinically evident volume overload (analysis of variance, p less than 0.001, alpha = 0.05 compared to normals). In patients with ESRD, the levels of IR-ANH were 145 +/- 46 pmol/l before dialysis and decreased to 87 +/- 31 after dialysis (p less than 0.025). No correlation was found between the decrease in IR-ANH levels and the decrease in weight during dialysis. A significant positive correlation was found between the IR-ANH levels and blood urea nitrogen in patients with CRF (r = 0.658, p less than 0.01). Volume overload appears to be the most important stimulatory factor for ANH secretion in renal failure patients but other mechanisms, especially a decrease in metabolic clearance, may also contribute to elevated plasma levels. The increased secretion of ANH in patients with renal failure may be an important adaptive response to volume overload and hypertension.

Continuous arteriovenous filtration: an effective treatment for surgical acute renal failure

Continuous arteriovenous hemofiltration (CAVH) is a new method of renal replacement therapy that has several advantages in the surgical treatment of acute renal failure. We initially learned the technique in laboratory testing and then developed a management protocol. Since 1983 we have used CAVH to treat 61 patients with acute renal failure. This extracorporeal technique consists of arteriovenous cannulation of the femoral vessels, which provides continuous blood flow through a hollow-fiber membrane. Hydrostatic pressure (systole greater than 80 mm Hg) creates an ultrafiltrate at a typical rate of 12 L/day. Volume is replaced with an intravenous solution at a rate to achieve the desired fluid balance, usually a net loss of 1 to 2 L/day. This extracellular fluid exchange typically results in removal of 15 gm of urea nitrogen and 50 mEq of potassium per day. The technique can be used in most intensive care units and has relatively few complications. In addition to being a safe and effective means of renal replacement therapy for acute renal failure, CAVH is particularly advantageous for managing conditions of fluid overload in hemodynamically unstable patients.

Successful treatment of Pseudomonas peritonitis during continuous ambulatory peritoneal dialysis

Successful eradication of Pseudomonas peritonitis is described in 12 (57%) of 21 cases from a large continuous ambulatory peritoneal dialysis (CAPD) program at a tertiary care center. In successful cases, cure was achieved within 17 days using therapy which included aminoglycoside started routinely at the onset of symptoms and an antipseudomonal penicillin or cephalosporin derivative added as soon as pseudomonas infection was identified on culture. Of the 9 treatment failures which required catheter removal, 2 had failure of peritoneal drainage, 4 had infection with multiple and/or drug-resistant Pseudomonas strains, and 3 had persistent catheter tunnel infection which resulted in recurrent Pseudomonas peritonitis. Factors such as diabetes mellitus and pediatric age group did not prevent successful medical therapy. Predisposing factors favoring development of Pseudomonas peritonitis included technical failures and in a few cases recent antibiotic therapy. We conclude that Pseudomonas peritonitis complicating CAPD can be successfully cured without catheter removal or discontinuation of CAPD in many cases, particularly when complicating factors are not present.

Continuous arteriovenous hemofiltration: improved survival in surgical acute renal failure?

Continuous arteriovenous hemofiltration (CAVH) is an effective method for renal failure management that has the potential to decrease mortality rates. This hypothesis has not been comparatively studied. Fifty six patients with acute oliguric renal failure complicating multiple organ failure had measurements of resting energy expenditure by indirect calorimetry, caloric and protein intake, energy balance, and outcome. Two management protocols included hemodialysis, full calories, and low protein (phase I) or CAVH, full calories, and high protein (phase II). The survival rate in phase I was 12% and 28% in phase II (not a statistically significant difference); CAVH did facilitate parenteral feeding. Patients with positive energy balance had improved survival compared with those with significant energy deficit (37.5% versus 9.4%, p less than 0.025). We conclude that full nutritional support improves survival in acute renal failure. The method of renal replacement therapy is of secondary importance, but CAVH has distinct advantages in the nutritional management of surgical patients.

Kinetics, dynamics, and bioavailability of bumetanide in healthy subjects and patients with chronic renal failure

Six patients with chronic renal failure (CRF group) and four healthy subjects (HS group) were given 5 mg oral and intravenous doses of bumetanide in a random, crossover design. The CRF group had significantly lower plasma and renal clearances, resulting in a five-to sixfold reduction in the fractional urinary excretion of the drug. The percent free drug in plasma for the CRF group was more than double that for the HS group, and significant correlations were observed for volume of distribution at steady state vs. percent free (r = 0.661; P less than 0.05), nonrenal clearance vs. percent free (r = 0.796; P less than 0.01), and renal clearance vs. creatinine clearance (r = 0.995; P less than 0.001). Although bioavailability was relatively consistent among the HS (0.664 +/- 0.112) and CRF (0.689 +/- 0.149) groups, the absorption-time profiles were more irregular for both groups. Cumulative sodium excretion and overall efficiency of response to bumetanide did not differ significantly between the two routes of administration in either group.

Peritoneoscopy in the management of catheter malfunction during continuous ambulatory peritoneal dialysis

Continuous ambulatory peritoneal dialysis is widely used in the maintenance of patients with chronic renal failure. Obstruction or displacement of the chronic dialysis catheter, which prevents dialysate drainage, can compromise ongoing dialysis. Conservative approaches (body position change, saline infusion, and enema) are often unsuccessful and more aggressive therapy may be required. We report the use of peritoneoscopy to reposition malfunctioning peritoneal dialysis catheters. The procedure proved to be safe and gave excellent long-term results.

Chronic peritoneal dialysis: mechanical and infectious complications

The present report summarizes the mechanical and infectious complications attributable to the devices and procedures used for chronic peritoneal dialysis (PD), comparing the type and frequency of such complications in contemporaneous groups of patients undergoing continuous ambulatory PD (CAPD) or intermittent PD (IPD). Mechanical complications related directly to the catheter and its placement proved to be equally frequent during CAPD and IPD. On the other hand, mechanical complications related to increased intraperitoneal pressure were more frequent during CAPD. In most instances mechanical complication can be managed without permanent interruption of chronic PD. Peritonitis occurs more frequently during CAPD (1.6 episodes per patient-year) than during IPD (0.4 episodes per patient-year), with a tendency to more frequent peritonitis among diabetics, children, patients with white blood cell abnormalities, patients with catheter cuff or tunnel inflammation, and during the 1st month of treatment. Medical therapy eradicates peritonitis and allows continuation of chronic PD with retention of the catheter in more than 90% of episodes, although special problems may be encountered with fungal, pseudomonal, and some coagulase-positive staphylococcal infections.

Intraleukocytic sequestration as a cause of persistent Staphylococcus aureus peritonitis in continuous ambulatory peritoneal dialysis

Peritonitis caused by Staphylococcus aureus in four patients undergoing continuous ambulatory peritoneal dialysis failed to respond to, or relapsed immediately after cessation of, intraperitoneal antibiotic therapy with vancomycin or cephalothin and tobramycin. Sequestration of viable staphylococci within polymorphonuclear leukocytes in the peritoneal fluid was suspected for two reasons: (1) staphylococci could still be grown after treatment of the dialysate cell fraction with lysostaphin, a procedure that kills only extracellular staphylococci, and (2) diminished polymorphonuclear leukocyte bactericidal activity was demonstrated in peritoneal dialysis effluent. Addition of rifampin, which readily penetrates polymorphonuclear leukocytes, to the treatment regimen of all patients led to prompt resolution of peritonitis without relapse.

Bicarbonate hemodialysis: influence on plasma refilling and hemodynamic stability

The present study compares the effect of sodium bicarbonate (LoNaHCO3, Na = 134, HCO3 = 33 mEq/l) and sodium acetate (LoNaAc, Na = 134, acetate 33 mEq/1)dialysate on the extravascular fluid mobilization (VFM) and hemodynamic changes in 6 patients during 3 h of hemodialysis with equivalent fluid ultrafiltration of about 600 ml/h. The cumulative decrease in plasma volume after 1, 2 and 3 h of dialysis was significantly less during LoNaHCO3 dialysis than during LoNaAc dialysis, with plasma volume almost completely refilled by VFM during the first 2 h of LoNaHCO3 dialysis. High sodium acetate dialysate (HiNaAc, Na = 144, acetate = 33 mEq/1) with equivalent fluid ultrafiltration also resulted in less net decrease in plasma volume and greater VFM than LoNaAc, although the temporal pattern of refilling was somewhat different from that during LoNaHCO3: rapid and complete refilling during the early portion of LoNaHCO3, slower and more progressive refilling during HiNaAc, with similar cumulative refilling for LoNaHCO3 and HiNaAc by 3 h. Mean arterial pressure (MAP) tended to decrease during LoNaAc dialysis, whereas MAP remained stable during LoNaHCO3 and increased slightly during HiNaAc. This study, therefore, suggests that improved hemodynamic stability utilizing bicarbonate dialysate may be due, in part, to greater plasma refilling and better preservation of plasma volume.