[Successful management of a man with fulminant myocarditis using percutaneous cardiopulmonary support]

Fulminant myocarditis is a fetal disease characterized by a distinct viral prodrome, sudden onset of severe hemodynamic compromise, and marked myocardial inflammation. One possible therapy to improve the poor prognosis of such patients may be the implantation of circulatory support systems that allow myocardial recovery. We report here successful management of a patient with fulminant myocarditis using percutaneous cardiopulmonary support (PCPS), intra-aortic balloon pump (IABP), and continuous hemodiafiltration (CHDF). A 37-year-old Japanese man suddenly experienced cardiopulmonary dysfunction shortly after general fatigue, and was diagnosed as having fulminant myocarditis. PCPS was immediately initiated because catecholamine infusion and IABP were not enough to support circulation. Although severe dyskinesis was observed on his admission, cardiac function recovered twelve days after PCPS initiation with ejection fraction from 16% to 73%. Renal and hepatic failure also recovered with the improvement of cardiac function. We describe our clinical experiences in cardiogenic shock after acute fulminant myocarditis and discuss therapeutic guidelines for the use of PCPS, with its management and complications.

Ultrafiltration improves aortic compliance in haemodialysis patients

An elevated pulse pressure leads to an increased pulsatile cardiac load, and results from arterial stiffening. The aim of our study was to test whether a reduction in volume overload by ultrafiltration (UF) during haemodialysis (HD) leads to an improvement of aortic compliance. In 18 patients, aortic compliance was estimated noninvasively before and after HD with UF using a pulse pressure method based on the Windkessel model. This technique has not been applied before in a dialysis population, and combines carotid pulse contour analysis by applanation tonometry with aortic outflow measurements by Doppler echocardiography. The median UF volume was 2450 ml (range 1000-4000 ml). The aortic outflow volume after HD (39 ml; 32-53 ml) was lower (P=0.01) than before (46 ml; 29-60 ml). Carotid pulse pressure after HD (42 mmHg; 25-85 mmHg) was lower (P=0.01) than before (46 mmHg; 35-93 mmHg). Carotid augmentation index after HD (22%; 3-30%) was lower (P=0.001) than before (31%; 7-53%). Carotid-femoral pulse wave velocity was not different after HD (8.7 m/s; 5.6-28.9 m/s vs 7.7 m/s; 4.7-36.8 m/s). Aortic compliance after HD (1.10 ml/mmHg; 0.60-2.43 ml/mmHg) was higher (P=0.02) than before (1.05 ml/mmHg; 0.45-1.69 ml/mmHg). The increase in aortic stiffness in HD patients is partly caused by a reversible reduction of aortic compliance due to volume expansion. Volume withdrawal by HD moves the arterial wall characteristics back to a more favourable position on the nonlinear pressure-volume curve, reflected in a concomitant decrease in arterial pressure and improved aortic compliance.

Massive hepatic infarction in preeclampsia: successful treatment with continuous hemodiafiltration and corticosteroid therapy

Massive hepatic infarction associated with pregnancy is extremely rare, but is potentially fatal. A 35-year-old primigravida with mild preeclampsia developed acute right upper quadrant pain and marked elevation of liver enzymes at 26 weeks' gestation. After emergent cesarean section, her condition was complicated by oliguric renal failure and pulmonary edema with further deterioration of hepatic function (aspartate transaminase 4339 IU/L; alanine transaminase 3489 IU/L; lactate dehydrogenase 10780 IU/L). The contrast-enhanced computed tomography revealed non-enhancing low attenuation throughout the right lobe of liver, compatible with infarction. Continuous hemodiafiltration was initiated as renal support on postpartum day one. However, excessive fluid accumulation persisted, and she developed severe edema formation in both lung and systemic body surface. To ameliorate microvascular endothelial injury, corticosteroid therapy was begun on postpartum day five. Following treatment initiation, her renal and hepatic function showed steady improvement, accompanied by drastic resolution of edema formation. She was discharged five weeks postpartum with no additional treatment, and is without sequelae six months later. Massive hepatic infarction should be considered in preeclamptic patients who present acute abdominal pain and severe hepatic dysfunction, and continuous hemodiafiltration with corticosteroid therapy may improve the maternal outcome.

Comparative analysis of immunophenotypic abnormalities in cellular immunity of uremic patients undergoing either hemodialysis or continuous ambulatory peritoneal dialysis

AIM

To investigate the abnormalities of cellular immune responses in patients on hemodialysis (HD) and in those on continuous ambulatory peritoneal dialysis (CAPD).

PATIENTS AND METHODS

Forty-five (45) healthy volunteers, 34 patients on HD therapy, and 37 patients on CAPD were recruited for the present study. Lymphocyte subpopulations (CD2+, CD3+, CD3+/CD4+, CD3+/CD8+, CD3-/16+56+, CD19, and CD4/CD8) were determined by flow cytometry.

RESULTS

Lymphopenia, decreased absolute counts, and altered percentage values of CD3+, CD3+/ 4+, and CD19+ subpopulations were found in both patient groups. The HD and CAPD patients showed increased percentages of natural killer cells (CD3-/16+56+) compared to controls but CD4+/CD8+ ratio showed no significant changes among uremic patients and controls.

CONCLUSIONS

Replacement therapy may contribute to the quantitative alterations of immune subsets found in HD and CAPD patients compared to normal subjects. We speculate that these changes account, at least in part, for the immune dysregulation observed in patients with chronic renal failure. Analysis of lymphocyte subsets will help the research and the evaluation of the possible causes of immunodeficiency in uremic patients undergoing replacement therapy and will probably contribute to more efficient and preventive strategies.

Two Spent Dialysate Samples are Sufficient for Hemodialysis Efficacy Assessment

Introduction

The measure of dialysis efficacy is expressed as Kt/V value (calculated from predialysis and postdialysis blood urea concentration). The aim of this study was to assess the possibility of direct calculation of Kt/V value from two spent dialysate samples by using the regular blood-based Kt/V calculation formula with dialysate samples used as surrogates for blood samples, and to detect the most appropriate couple of dialysate samples for Kt/V estimation.

Patients and Methods

Fifty-two single hemodialysis treatments in 34 anuric patients on chronic bicarbonate low-flux hemodialysis were observed. Kt/V values according to Daugirdas formula from two blood samples and from two dialysate samples were calculated.

Results

Kt/V values calculated according to Daugirdas 2nd generation formula from blood samples (Kt/Vsp Daugirdas) were in significant correlation with all Kt/V values obtained from two spent dialysate samples. The highest correlation coefficient (r = 0.74, p & 0.001) and the least standard error of mean of the differences were found between Kt/Vsp Daugirdas and value obtained with substitution of urea concentration from dialysate samples taken 60 minutes after dialysis start and at the end of the dialysis into Daugirdas 2nd generation formula (Kt/VDCD(60)-CD(e)), which can be expressed as a equation of linear regression y = 0.47 + 0.86x. The highest correlation coefficient (r = 0.74, p & 0.001) was found between Kt/Vsp Daugirdas values equilibrated according to Daugirdas rate formula, and Kt/VDCD(60)-CD(e) value, which can also be expressed as an equation of linear regression y = 0.43 + 0.73x.

Conclusion

The results of this study clearly show the sufficiency of only two spent dialysate samples for direct estimation of the Kt/V values, with no blood sample required.

[Behaviour of vancomycin with the new techniques in haemodialysis]

When using high convection dialysis techniques it arouses the necessity of considering the suitability of the regular protocols when administrating drugs, such as vancomycin.

OBJECTIVES

To confirm if the usual guideline of vancomycin is efficient in patients undergoing treatments with acetate free biofiltration (AFB) and haemodiafiltration on-line (on-line). To propose an alternative guideline of administration.

MATERIAL AND METHODS

13 patients treated with AFB or On-line. 10 of them used filters of polysulfone and 3 of them of AN69. First part: 6 patients were administered 1 g iv during the last hour of dialysis. Second part: 7 patients were given a loading dose of 30 mg/kg iv with a reinforcement of 500 mg post-dialysis. The blood levels of the antibiotic were monitorized during the week following the administration.

OUTCOMES

During the first phase it was noticed a decrease of 41% in the serum level of vancomycin during dialysis, conditioning subtherapeutic levels in the 83% of the patients until the end of the study. As for the second phase, therapeutic non-toxic levels were maintained during the whole study. The existence of a post-dialysis rebound of the 21 % was confirmed. A bigger clearance of vancomycin was obtained with the On-line technique rather than with AFB (176 vs 135 ml/min). We find a strong correlation between the decrease of the antibiotic and the volume ultrafiltrated with the On-line technique.

CONCLUSIONS

The usual guideline of vancomycin may not be enough with the new convective dialysis techniques. A guideline based on a loading dose of 30 mg/kg and a reinforcement of 500 mg at the end of each dialysis could be adequate. The antibiotic clearance with the On-line technique is probably made by convective transport.

[Nephropathy caused by radiocontrast media]

The paper contains the overview of the definition, clinical features, pathomechanism and the risk factors of the radiocontrast-induced nephropathy. Authors reviewed the methods of prevention and treatment of the renal failure induced by radiocontrast media with the special attendance to the results of the latest clinical trials.

[Common places on clinical management of acute renal failure]

Acute renal failure (ARF) is an abrupt decline of renal function, and acute tubular necrosis (ATN) is its more frequent expression. Recent contributions in physiopathological knowledge, specially in post-ischemic ARF, are scarcelly reflected in therapy. Morbidity and mortality due to ARF are very high, mainly in critically ill patients. Prevention and treatment of ATN are based in avoiding nephrotoxicity and renal ischemia. An adequate evaluation of renal risk factors in hospitalized patients is important. Maintaining euvolemia, effective cardiac output and adequate renal perfussion pressure are three paramount factors in ischemia prevention. The best dialytic schedule is not universally accepted. ARF replacement therapy must be flexible, tailoring techniques (IHD, SLED, CRRT) to the clinical situation of patients. There is not a consensus in dialysis dose in ARF. Nevertheless, despite a robust scientific evidence is lacking, some data suggest that a delivered minimum dose of sKtV >1 in IHD or >35 ml/kg/h in CRRT would be beneficial for patient survival.

Mathematical Model to Characterize Internal Filtration

Convective-diffusive dialysis techniques have recently gained considerable favor. Indeed, convective fluxes through dialyzer membranes have been demonstrated to play a role in enhancing the clearance of middle-molecular-weight solutes. An interesting opportunity is given by exploiting the internal filtration (IF)/back filtration mechanism that occurs spontaneously in high-flux dialyzers, but is difficult to quantify. In view of overcoming this drawback, a semi-empirical, lumped-parameter mathematical model for characterization of IF phenomena was developed. The model considers a dialyzer as composed by N adjacent axial blocks. For each block, hydrodynamics in the blood and dialysate compartments are determined considering hydraulic resistance and calculating local filtration. Blood viscosity and oncotic pressure are calculated locally based on hematocrit and protein concentration. Resistance parameters were determined experimentally for the BS-UL (Toray Industries Inc., Tokyo, Japan) dialyzers. The set of equations describing the model, implemented into a software program, is solved using a numerical method. Simulations allow highlighting the role of device-, treatment- and patient-dependent parameters in affecting IF. Provided an extensive validation is carried out, the use of a mathematical model could be the key to make IF more understandable and its use reliable in clinical practice.

Clinical and Experimental Evidence for Prevention of Acute Renal Failure Induced by Radiographic Contrast Media

Acute renal failure still occurs as a complication after radiographic examination using iodinated radiocontrast medium. The incidence rate of radiocontrast medium-induced nephropathy (radiocontrast nephropathy) is low (2 - 3%) in general. However, the rate is remarkably elevated in patients with pre-existing renal insufficiency. Radiocontrast nephropathy is associated with increased morbidity and mortality, particularly in patients with percutaneous coronary interventions. Although the reduction in renal blood flow and direct toxic action on renal tubular cells are considered to be involved, little is known about the etiology of radiocontrast nephropathy. A number of agents that improve renal circulation have been clinically tested for prevention of radiocontrast nephropathy, but none of them has succeeded. Protection of renal tubular cells against oxidative stress is another approach to avoid radiocontrast nephropathy. Prophylactic effects of antioxidants such as N-acetylcysteine and ascorbic acid have been reported by several investigators, although the effectiveness of these compounds is still a matter of debate. At present, hydration is regarded as the only effective, though incomplete, prophylactic regimen for radiocontrast nephropathy. Recently, we have shown that caspase-dependent apoptosis is an important factor in the pathogenesis of radiocontrast nephropathy and clarified cellular mechanisms underlying the radiocontrast media-induced apoptosis. This review summarizes clinical and experimental evidence for the etiology and prevention of radiocontrast nephropathy.

Machines for Hemodialysis

Basic functions of hemodialysis machines are described. The paper focuses on essential treatment parameters and safety aspects. The cause of safety hazards and protective systems for amelioration of these hazards are described. With the exception of hemolysis caused by obstructions in the extracorporeal circuit and blood losses caused by user errors machine related accidents are rare. Foreseeable improvements of next generation hemodialysis machines will reduce the likelihood of accidents further. The accuracy of adjusted or monitored treatment parameters that may influence outcome (dialysate concentration, ultrafiltration, blood flow and on-line measured clearance) is discussed.

A Comparison of Bicarbonate Hemodialysis, Hemodiafiltration, and Acetate-free Biofiltration on Cytokine Production

Acetate-free biofiltration (AFB) is a special hemodiafiltration (HDF) modality performed with a base-free dialysate and simultaneous injection of non-pyrogenic sodium bicarbonate solution. The purpose of this study was to investigate the difference of cytokine production by conventional bicarbonate hemodialysis (BCD), standard HDF and AFB in the same patients. Eight stable hemodialysis patients were treated in random order with BCD, HDF and AFB every 4 weeks. The production of interleukin-1 beta (IL-1 beta) and interleukin-1 receptor antagonist (IL-1Ra) by peripheral blood mononuclear cells (PBMC) was investigated without stimulation and with stimulation by a small amount of endotoxin (ET)-contaminated beta 2-microglobulin (beta 2M) and lipopolysaccharide (LPS) before and after dialysis treatment in the last sessions during all periods. To serve as controls, 14 healthy volunteers participated in this study. In spontaneous IL-1Ra production, the values of before and after AFB were not significantly different from that of the controls, and the values of before and after BCD and before HDF were significantly higher than that of the controls. In LPS-stimulated PBMC, IL-1 beta production before and after AFB was not significantly different from that of the controls, and before and after BCD and HDF was significantly higher than that of the controls. In ET-contaminated beta 2M-stimulated PBMC, IL-1 beta production before and after AFB was not significantly different compared to the controls, and the production was significantly lower than that before and after BCD and HDF. In addition, IL-1Ra production after AFB was not significantly different from the controls, and the production was significantly lower than that before and after BCD and HDF. It was concluded that a lower cytokine production by AFB may have the effect of preventing dialysis-related complications.

[Pharmacokinetic simulation of different modes of renal replacement therapy]

Based on the results of examination of patients with severe acute renal failure and multiorgan insufficiency, the authors give a comparative analysis of different modes of renal replacement therapy, such as intermittent hemofiltration, continuous arteriovenous hemofiltration, and continuous venovenous hemodiafiltration. Kinetic simulation in terms of urea and creatinine, by employing a one- and two-pool model for the disposition of these substances in the patient's body was taken as a basic method. The analysis led to the conclusion that continuous hemodiafiltration (CHDF) with an actually large volume of filtration and dialysis was the optimum technique for correcting uremic impairments of homeostasis in critically ill patients. CHDF failed to induce a significant metabolic stress and to noticeably affect the rate of urea and creatinine generation. Overall, all the filtration treatments are an effective means of eliminating low-molecular-weight nitrogenous metabolites that are characterized by the high rate of generation and the large volume of disposition in the organism. It is necessary only to correctly select a dose of renal therapy.

Accurate dry weight assessment: reducing the incidence of hypertension and cardiac disease in patients on hemodialysis

Hypertension is a major cause of cardiac disease in patients on hemodialysis (HD) and is most commonly due to hypervolemia. Removal of excess water during HD can successfully normalize blood pressure, but its success depends on an accurate assessment of dry weight. This article reviews the literature concerning hypertension in patients on HD and proposes that increased attention by dialysis staff to assessing dry weight may reduce the incidence of hypertension and cardiac disease in these patients.

[Vitamin B12 clearance (Kd-B12) in hemodialysis (HD) and hemodiafiltration (HDF)]

PURPOSE

The dialysis dose is usually assessed by Kt/V urea; however, it is possible that middle molecule (MM) removal could play a role in optimal treatment. Vitamin B12 is a classical MM marker and Kd-B12 is used to compute a MM-based dialysis index, requiring a weekly total clearance (Kd-B12 + renal creatinine clearance (CrCl) > or =30 L, corresponding to IDB12> or =1 (Babb et al, Kidney Int, 1975). Recently, it was demonstrated that by increasing the total Kd-B12 per session (TCV) from 10 to 16 and to 26 L, the relative risk (RR) of death was reduced from 1 to 0.79 and to 0.62, respectively (Leypoldt et al, Am J Kidney Dis 1999). This implies that a minimum TCV of 16 L, but preferably of 26 L per session, should be delivered, for anuric HD patients on a 3x/wk schedule. To extend these results to the whole hemodialysis (HD) population, we suggest transforming TCV into the corresponding IDB12 values: i.e. a TCV=10 L on 3x/wk corresponds to IDB12=1, a TCV=16 and 26 L corresponds to IDB12=1.6 and 2.6, respectively.

METHODS

This study aimed to assess Kd-B12 and IDB12 for all stable patients in our unit. There were 62 patients (33 males, 29 females): five patients were being dialyzed once per week (1x), nine patients twice (2x), 46 patients three (3x) and two patients four times (4x) per week (wk); the session length was 232+/-18 min. Most dialyzers had a large surface area (mean 1.9+/-0.3 m2), with KoA-B12=211+/-92 mL/min. Eleven patients, 3x/wk, were on hemodiafiltration (HDF): the reinfusion rate was 33+/-3 mL/min in five patients (sHDF) and 76+/-12 mL/min in six patients (HDF on-line (OL). Kd-B12 was computed as a function of KoA-B12, effective plasma flow, Qd and ultrafiltrate (UF). IDB12 was computed from Kd-B12, ses-sion length and schedule, CrCl and body surface area.

RESULTS

The main results are given below: [table: see text] On average, Kd-B12 was 105 +/- 13 mL/min on HD and 152+/-34 mL/min on HDF. A significant difference was found only for HDF-OL and was essentially due to the higher UF. Of note, the presence of renal function allowed good IDB12 values for 1x/wk and 2x/wk patients, even better than for the standard 3x/wk patients.

CONCLUSIONS

We have demonstrated that most available dialyzers provide high Kd-B12 values (but HDF-OL performs significantly better) and that IDB12, by quantifying the impact of UF, session length, schedule and renal function, allows the assessment of dialysis adequacy beyond Kt/V urea, for all HD or HDF patients, on a routine basis and at no added cost.

Valproic acid intoxication: sense and non-sense of haemodialysis

INTRODUCTION

Valproic acid is increasingly used in the treatment of epilepsy, and also prescribed for bipolar affective disorders, schizoaffective disorders, schizophrenia and migraine prophylaxis. We describe two case reports involving valproic acid intoxication with ingestion of ethanol.

METHODS

One patient was treated by supportive care, one patient received haemodialysis.

RESULTS

From analysis of plasma concentrations before and during haemodialysis (pre- and post-filter) it is shown that valproic acid can be effectively eliminated by haemodialysis when plasma levels are way above 100 microg/ml. In the literature, plasma protein binding is reported to be around 90% for levels within the therapeutic range. In our patient plasma protein binding was around 50% after treatment with haemodialysis.

CONCLUSION

These findings make haemodialysis in valproic acid intoxication a sensible therapeutic option with increasing efficiency when plasma concentration is high. Furthermore our findings suggest that lowering valproic acid concentrations to a therapeutic level by haemodialysis does not necessarily result in an immediate, simultaneous increase in plasma protein binding of valproic acid.

Acidose lactique majeure secondaire à une intoxication volontaire par valproate

A sixty-year-old woman was admitted in the ICU after Depamide (Valpromide) self-poisoning (430 mg/kg). Four hours after the ingestion, the patient presented coma (Glagow coma score of 3) with bilateral mydriasis requiring tracheal intubation and mechanical ventilation, hypotension requiring epinephrine infusion (0.9 microg/kg per minute), acidosis and hyperlactatemia (29.7 mmol/l at 12 hours) without any kidney or liver failure. The maximal serum valproic acid concentration measured was 342 mg/l after twelve hours (therapeutic rate: 35-85 mg/l). A continuous infusion of sodium bicarbonate was associated with continuous venovenous haemodiafiltration. Progressive haemodynamic improvement and neurologic recovery leaded to extubation at 36 hours.

Minimal change disease with acute renal failure: a case against the nephrosarca hypothesis

An unusual but well-documented presentation of minimal change disease is nephrotic proteinuria and acute renal failure. One pathophysiological mechanism proposed to explain this syndrome is nephrosarca, or severe oedema of the kidney. We describe a patient with minimal change disease who presented with heavy proteinuria and acute renal failure but had no evidence of renal interstitial oedema on biopsy. Aggressive fluid removal did not reverse the acute renal failure. Renal function slowly returned concomitant with resolution of the nephrotic syndrome following corticosteroid therapy. The time profile of the clinical events is not compatible with the nephrosarca hypothesis and suggests an alternative pathophysiological model for the diminished glomerular filtration rate seen in some cases of minimal change disease.

Combined twice-daily plasma exchange and continuous veno-venous hemodiafiltration for bridging severe acute liver failure

Aiming to remove the toxins produced during the course of severe hepatic failure, we combined hemodiafiltration and plasma exchange (patient plasma replaced by fresh frozen plasma in a twice-daily regimen) for treatment of five patients: two affected by primary nonfunction of a liver graft and three by fulminant hepatic failure. The simultaneous use of the two extracorporeal techniques allowed a rapid reduction in the administration of vasoactive drugs and a rapid, significant decrease in the indices of liver necrosis. Native liver functional recovery occurred in one case, and the wait for a second graft was made possible in the other four. Although it has been reported that the detoxifying efficacy of plasma exchange is optimal when the replaced volume of plasma is high, such a technique requires both long treatment times and high blood flows in the extracorporeal circuit, making it often hemodynamically intolerable. Our approach leads to replacement of smaller volumes, allowing lower blood flows that are better tolerated despite the often unstable hemodynamics of these patients. Liver transplantation and retransplantation remains the definite therapy for severe liver failure or primary nonfunction. However, the organ waiting time is unpredictable and often does not coincide with the patients' clinical needs. Thus alternative strategies must be developed until a suitable donor is found or there is spontaneous recovery. From this point of view, in our albeit limited experience, twice-daily plasma exchange combined with hemodiafiltration has proved to be an effective therapeutic approach.

Recommendations for the use of icodextrin in peritoneal dialysis patients

Icodextrin is a starch-derived, high molecular weight glucose polymer, which has been shown to promote sustained ultrafiltration equivalent to that achieved with hypertonic (3.86%/4.25%) glucose exchanges during prolonged intraperitoneal dwells (up to 16 h). Patients with impaired ultrafiltration, particularly in the settings of acute peritonitis, high transporter status and diabetes mellitus, appear to derive the greatest benefit from icodextrin with respect to augmentation of dialytic fluid removal, amelioration of symptomatic fluid retention and possible prolongation of technique survival. Glycaemic control is also improved by substituting icodextrin for hypertonic glucose exchanges in diabetic patients. Preliminary in vitro and ex vivo studies suggest that icodextrin demonstrates greater peritoneal membrane biocompatibility than glucose-based dialysates, but these findings need to be confirmed by long-term clinical studies. This paper reviews the available clinical evidence pertaining to the safety and efficacy of icodextrin and makes recommendations for its use in peritonal dialysis.