Clinical outcomes of hemodialysis patients in a public-private partnership care framework in Italy: a retrospective cohort study.

BACKGROUND: Innovative care models such as public-private partnerships (PPPs) may help meet the challenge of providing cost-effective high-quality care for the steadily growing and complex chronic kidney disease population since they combine the expertise and efficiency of a specialized dialysis provider with the population care approach of a public entity. We report the five-years main clinical outcomes of a population of patients treated on hemodialysis within a PPP-care model in Italy. METHODS: This descriptive retrospective cohort study consisted of all consecutive hemodialysis patients treated in the NephroCare-operated Nephrology and Dialysis unit of the Seriate Hospital in 2012-2016, which exercises a PPP-care model. Clinical and treatment information was obtained from the European Clinical Database. Hospitalization outcomes and cumulative all-cause mortality incidences that accounted for competing risks were calculated. RESULTS: We included 401 hemodialysis patients (197 prevalent and 204 incident patients) in our study. The mean cohort age and age-adjusted Charlson Comorbidity Index were 67.0 years and 6.7, respectively. Patients were treated with online high-volume hemodiafiltration or high-flux hemodialysis. Parameters of treatment efficiency were above the recommended targets throughout the study period. Patients in the PPP experienced benefits in terms of hospitalization (average number of hospital admissions/patient-year: 0.79 and 1.13 for prevalent and incident patients, respectively; average length of hospitalization: 8.9 days for both groups) and had low cumulative all-cause mortality rates (12 months: 10.6 and 7.8%, 5 years: 42.0 and 35.9%, for prevalent and incident patients, respectively). CONCLUSIONS: Results of our descriptive study suggest that hemodialysis patients treated within a PPP-care model framework received care complying with recommended treatment targets and may benefit in terms of hospitalization and mortality outcomes.

Rare presentation of endometrial carcinoma with singular bone metastasis.

The major symptom at diagnosis of endometrial cancer is post-menopausal bleeding; it is present in around 90% of cases. Singular bone metastasis is described as an uncommon site for endometrial cancer at diagnosis, showing in just 5-6% of cases. In this report we describe a rare presentation of a singular bone metastasis because of endometrial cancer of a woman with previous diagnosis of early breast cancer. A review of literature uncovered some cases of bone metastasis at presentation of endometrial cancer and that it can occur as first symptom of cancer before vaginal bleeding. This rare presentation of uterine cancer needs to be studied and described because it may be seen and needs a homogeneous treatment to improve survival.

[Convective and mixed dialysis technique]. / Le tecniche dialitiche miste convettive-diffusive.

Hemodiafiltration is the dialytic strategy enabling the high potential of hydraulic and solute permeability of synthetic membranes to be most properly exploited, thus greatly enhancing removal of small and middle-molecular toxic compounds. Several of those solutes have a pathogenic role or are recognized as marker of the most frequent long-term complications and causes of death in HD patients, such as dialysis related amyloidosis, cardio-vascular disease, secondary hyperparatyroidism, inflammation and malnutrition. Improved survival in dialysis has been associated, in observational studies, with the use of high-flux membranes and hemodiafiltration with high volume exchange. On-line production of unlimited amount of sterile dialysate at low cost has favored its extensive diffusion in the recent years, and optimal biocompatibility of synthetic high-flux membranes and the quality of the ultrapure dialysate have contributed to the promising results of the technique. However, to optimize its clinical application and achieve safely the most efficient convective transport, knowledge is required of dialysis systems, dialyzer characteristics and performances, and of the complex interactions between patient and membrane. New hemodiafiltration techniques have been proposed in these years with the aim to improve the efficiency and safety of the technique. More generally, technical aspects and requirements, and experimental and clinical results of the convective-mixed treatments are examined here.

[Census of the Italian Nephrology and Dialysis Units. Comparison between Lombardy and Piedmont]. / Censimento 2004 Centri di Nefrologia e Dialisi. Confronto tra Piemonte e Lombardia.

The Italian Society of Nephrology promoted a national survey to obtain detailed information from all the Renal and/or Dialysis Units through an on-line questionnaire concerning structural, technological and human resources, as well as organisation characteristics and activities. The purpose of this initiative was to obtain regional reference benchmarks for each Nephrology Unit. In this paper we compare two northwestern Italian Regions: Lombardy and Piedmont. As far as epidemiology is concerned, the prevalence of dialysis patients is quite similar in the two Regions: for haemodialysis 616 pmp (patients per million population) in Lombardy and 595 in Piedmont, for peritoneal dialysis 104 pmp vs. 114 pmp, while the incidence of dialysis patients is 169 vs. 166 pmp. The gross mortality for dialysis patients is 12.4% vs. 13.7% and 0.9% vs. 2.0% in transplanted patients. The distribution of vascular access is also quite similar in the two Regions: prevalent arteriovenous fistula 83% vs. 74%, central venous catheter 11% vs. 18%, vascular grafts 7% vs. 8%. Structural resources: the hospital beds (49 pmp in the two Regions) and the dialysis places (161 vs. 166 pmp) do not differ between the two Regions. Personnel resources: physicians 37 pmp in Lombardy and 44 pmp in Piedmont, renal nurses 167 pmp vs. 186, respectively. Activity: hospital admission 1722 pmp vs. 1507 pmp, renal biopsies 131 pmp vs. 109 pmp. Although the two regions examined are numerically different, both have a high standard of quality, making Italy a model of nephrology organisation. This initiative to take a census of the Italian Nephrology and Dialysis Units provides an interesting tool to describe the present status of the operational structures, to identify precise benchmarking values, at both the regional and national level, and to act as a prelude for further rationalization and growth of the nephrology network in Italy.

[Guidelines on water and solutions for dialysis. Italian Society of Nephrology]. / Linee Guida su acque e soluzioni per dialisi.

The National Society of Nephrology has promoted the development of specific Italian Guidelines for dialysis fluids. Two previous national inquiries showed a wide variety in the type and frequency of both microbiological and chemical controls concerning dialysis water, reinforcing the need for specific standards and recommendations. An optimal water treatment system should include tap water pre-treatment and a double reverse osmosis process. Every component of the system, including the delivery of the treated water to the dialysis machines, should prevent microbiological contamination of the fluid. Regular chemical and microbiological tests and regular disinfection of the system are necessary. 1. Chemical quality (Table: see text). Treated tap water used to prepare dialysis fluid should be within European Pharmacopoeia limits at the water treatment system inlet and at the reverse osmosis outlet. In addition dialysate, concentrate and infusion fluids must comply with specific Pharmacopoeia limits. The physician in charge of the dialysis unit is advised to institute a multidisciplinary team to evaluate the requirement for added chemical controls in the presence of local hazards. 2. Microbiological quality (Table: see text). High microbiological purity of dialysis fluid--regularly verified--is a fundamental prerequisite for dialysis quality and every dialysis unit should aim as a matter of course to obtain "ultra-pure" dialysate (microbial count <0.1 UFC/mL, endotoxins <0.03 U/mL). On-line dialysate ultrafiltration and regular disinfection of dialysis machines greatly enhance microbiological purity. On-line dialysate reinfusion requires specific devices used according to corresponding instructions and to more frequent microbiological tests. Dialysis fluids for home dialysis should comply with the same chemical and bacteriological quality. The appendix reports the water treatment system's technical characteristics, sampling and analytical methods, monitoring time-tables, as well as the origin and effects of the main toxic substances. Suggestions and questions concerning these guidelines are welcome to nefrologia@sin-italy.org.

Calcium-PTH relationship in dialysis patients: the pitfalls of using a constant dialysate calcium concentration during the dynamic tests.

The calcium-PTH relationship in uremic patients has been often studied during dialysis sessions with high or low dialysate calcium concentration (CaD). This method has been used because it is less complex and invasive than i.v. infusion of calcium salts and calcium chelating agents. However, the constancy of CaD during the tests does not allow for the control of the serum calcium profile and, given that the blood calcium concentration is only one factor of a more complex calcium-related mechanism of the PTH release, the calcium-PTH curve may become dependent on the unpredictable rate at which the ionized calcium changes. Dynamic testing of the parathyroid gland was performed in 9 dialysis patients comparing constant CaD of 1.0 and 2.0 mmol/l (A) with a linear change in CaD (B). The rate of serum calcium change remained constant over time only in experiment B. The total decrease in calcemia (0-0.38 +/- 0.03 vs -0.14 +/- 0.1 mmol/l) and PTHmax (748.25 +/- 124.76 vs 374.89 +/- 53.03 pg/ml) were significantly higher in B, whereas the total increase in calcemia (+0.26 +/- 0.03 vs +0.28 +/- 0.02 mmol/l) and the minimum value of PTH (59.15 +/- 9.53 vs 55.64 +/- 9.08 pg/ml) were similar in both experiments. The calcium-PTH curves were clearly different in A and B. The setpoint and the slope were significantly higher in A (1.196 +/- 0.01 vs 1.142 +/- 0.02 mmol/l; 840.54 +/- 96.85 vs 542.43 +/- 112.26%/mmol). For similar serum calcium values (1.084 +/- 0.01 vs 1.059 +/- 0.02 in the stimulation test and 1.325 +/- 0.02 vs 1.336 +/- 0.02 mmol/l in the inhibition test) the PTH secretion was significantly different (335.86 +/- 44.36 vs 647.65 +/- 104.09 in the stimulation test and 76.35 +/- 12.57 vs 105.03 +/- 20.59 pg/ml in the inhibition test). In conclusion, the way of inducing serum calcium change affected the calcium-PTH curve and the value of the set point and the slope was a function of the way in which the blood calcium changes were achieved. The modulated CaD dialysis was shown to be a more correct method of studying the calcium-PTH relationship in dialysis patients, as well as an alternative to the more complex and invasive infusional methodology.

Natural history of patients with carotid stenosis waiting for surgical treatment.

BACKGROUND AND PURPOSE: The natural history of carotid lesions has generally been evaluated in anedoctal series or in clinical trials. The purpose of this study was to evaluate clinical and pathological modifications linked to an increasing waiting list in our region and the related medico-legal implications. METHODS: Neurological symptoms that occurred during the waiting period were evaluated in 282 out of 491 patients placed on the waiting list for a carotid stenosis less than 80% or without an unstable plaque. The other 202 patients cancelled their booking. Progression of carotid disease was evaluated by duplex scanning in 116 patients who had a duplex evaluation in our Department both at booking and at the time of operation. RESULTS: The incidence of stroke in a mean waiting period of 8.9 months was 2.6% in symptomatic patients and 1.5% in asymptomatic, respectively; 39 (13.8%) patients experienced an ipsilateral TIA and 4.2% a carotid thrombosis (25% of which symptomatic). The crude mortality-rate was 2.4% with a 1% of related deaths. The cumulative actuarial hard end points rate (stroke, carotid thrombosis and related death) was 7.8% at 12 months and 19.8% at 18 months. CONCLUSIONS: This study gives us data about the natural history of carotid stenosis in our country. The high morbidity and mortality-rate related to this lesion and particularly their occurrence within the first 3 months stress the urgency of treatment, and of the planning of specialized Departments in relation to the real incidence of the pathology in order to avoid medico-legal consequences.

Morbidity and mortality following carotid surgery.

The records of 920 patients who underwent carotid endarterectomy by the same surgeon (M. D'A) between 1976 and 1989 were reviewed. Particular attention was paid to both the neurological and general complications and to how and when the neurological symptoms appeared. Among these patients, a cumulative stroke plus death rate of 3.1% was observed. Complications were classified as clamping ischemia (2.2%), postoperative embolism (1.5%), postoperative thrombosis (2.4%), and cerebral haemorrhage (0.3%). Two patients (0.2%) died from myocardial infarction. In 3.5% of patients, neurological symptoms were transient. The incidence of clamping ischemia was higher when 40 mmHg was considered as the safety limit of the back-pressure; this incidence fell by raising this limit to 50 mmHg, and introducing, in recent years, SEPs monitoring. Intraoperative monitoring of SEPs, in fact, reduced the neurological complications to 1.4%, while intraoperative angiography reduced the need for intraoperative reoperation from 10% to 2%. The use of antiplatelet drugs and an accurate surgical technique are useful steps in the prevention of postoperative embolism or thrombosis.

Ischemia-reperfusion syndrome: an alternative experimental model.

OBJECTIVE: To design an alternative experimental model of ischemia-reperfusion syndrome. Our model mimics the clinical pattern of the syndrome and also assesses the efficacy of therapeutical protocols. EXPERIMENTAL DESIGN: Ischemia was induced under general anaesthesia in the posterior limbs of 10 sheep by occluding the aorta and vena cava by means of two-way balloon catheters. Ischemia was stopped after 4 hours and blood and histologic parameters determined in the first three hours of revascularization. The animals were divided into three groups: a group of 3 sheep in which a sham operation was performed; a control group (5) to assess the efficacy of induced ischemia; the third group (5) to determine the effect of antioxidant and membrane protective drugs to assess the reliability of the model to study the ischemia-reperfusion syndrome. RESULTS: At the end of ischemia, skin temperature was decreased (p < 0.04) both in control and treated groups, pH decreased significantly soon after reperfusion in the control group (p < 0.04). Reperfusion in control sheep, compared with treated animals, was followed by a significant increase in CPK blood levels (p < 0.009), related to marked muscle damage, in particular after reperfusion. Tissue damage detected at TEM was less severe in treated animals. CONCLUSIONS: This model is an effective experimental strategy and a means of assessing preventive treatment.

Intermittent ischemia caused by dissection of the abdominal aorta through myxoid degeneration. Case report.

Acute intermittent ischemia is generally caused by altered vasomotion and rarely by aortic dissection. There is reported a case of dissection of the abdominal aorta which presented a mixoid degeneration of the inner wall. The surgical finding was similar to a medio intimal aortic cylinder obtained generally during endarterectomy. Five years after the operation (endarterectomy of the mixoid cylinder) the patient presents a good patency of the aortoiliac area.

Superior vena cava thrombosis secondary to thoracic outlet syndrome. Case report.

A case of superior vena cava thrombosis secondary to the thoracic outlet syndrome is reported. The diagnosis was revealed by CT-scan and confirmed by phlebography performed to insert a catheter for intrathrombotic infusion of urokinase. The thrombolytic treatment was followed by complete clot lysis. A hyperabduction manoeuvre confirmed costoclavicular compression as the cause of the subclavian-axillary vein thrombosis for which the patient underwent first rib resection. Axillary-subclavian vein thrombosis (or Paget-von Schroetter syndrome) is a relatively frequent complication of the thoracic outlet syndrome often treated with anticoagulants on the basis of a duplex examination. Involvement of the superior vena cava is not readily detected by duplex ultrasound so a partial thrombosis, with a possible fatal outcome could remain undiagnosed. Full investigation by phlebography or CT-scan is therefore recommended. In addition, transcatheter thrombolytic therapy has a lower incidence of follow-up complications than heparin.

Carotid endarterectomy in young adults.

The results of carotid endarterectomy in 521 patients were analyzed to verify whether the early and late outcome in young patients is worse than in older patients, such as the results observed in peripheral arterial reconstruction in young adults. The patients were subdivided into 3 groups: 105 under 55 years, 397 aged between 56 and 74 years and 19 over 75 years. Young patients presented less risk factors and associated diseases than older ones, with the exception of smoking-habit; on the other hand, they presented a higher incidence of early post-operative thrombosis, myocardial infarction and of recurrent stenosis at follow-up. This trend has already been observed in other series. Young age and smoking habit have also been significantly related with recurrent carotid stenosis. In spite of these complications, carotid endarterectomy is indicated in severe stenosis or complicated carotid plaques, in young adults, because of a low operative mortality and a better trend in the follow-up period; however, the pre-operative evaluation needs a more accurate study and, when possible, the normalization of metabolic risk factors and the elimination of smoking.

Iatrogenic vascular lesions. Pathogenesis and treatment: an 18 year review.

The records of 304 patients operated on for vascular injuries were reviewed; 76 (25%) of these presented an iatrogenic vascular injury: 13 involved the upper limbs, 49 the lower limbs and 14 the neck and trunk. The lesions were due to a vascular catheterism in 40 patients, to orthopaedic treatment in 27 patients, to general surgery procedure in 3 patients, to urologic surgery in 3 and to otorhinolaryngologic surgery in 3. In vascular catheterism the prevalent complications were thromboses and embolisms; 3 patients needed an amputation after the surgical repair. In orthopaedic surgery, vascular complications were linked prevalently to hip surgery, exchange arthroplasty and upper tibial osteotomy. In urologic, otorhinolaryngologic and general surgery, vascular lesions were prevalently related to haemorrhagic complications, followed by incorrect haemostatic manoeuvres. Retroperitoneal fibrosis or previous surgery increased the risk of vascular injuries. Delay in treatment was responsible for post-operative death or incomplete recovery.

Cerebral SPECT with 99mTc-HMPAO in extracranial carotid pathology: evaluation of changes in the ischemic area after carotid endarterectomy.

The authors report their experience in studying patients undergoing carotid endarterectomy with simple photon emission computed tomography (SPECT). This technique made it possible to identify areas of preoperative cerebral hypoperfusion in 54.8% of the patients which had a good correlation with neurological symptoms. To distinguish gradual changes in the ischemic lesions, a method of assessing the surface of the hypoperfused areas was adopted. In addition, SPECT made it possible to detect a greater number of hypoperfused areas even in sites other than those revealed by CT. Moreover, there was good correlations between the SPECT data and the grade and site of the carotid lesion and the data provided by some intraoperative monitoring procedures. The Authors therefore propose the use of SPECT in the evaluation of patients with cerebrovascular insufficiency following a carotid disease.

Intraoperative assessment of cerebral ischaemia during carotid surgery.

BACKGROUND: This study aimed to evaluate the reliability of somatosensory evoked potentials (SEPs) in identifying clamping ischaemia during carotid surgery under general anaesthesia. METHODS: We reviewed the records of 196 consecutive carotid endarterectomies (CEA) performed under general anaesthesia, out of 1550 patients operated on between 1975 and 1993. SEPs were monitored after contralateral median nerve stimulation at the wrist in all patients. Moreover they received an intravenous bolus of 2500 IU of heparin and the stump pressure was measured. A completion angiography was performed in all patients. An intraluminal shunt was inserted when the amplitude of the N20-P25 SEPs complex decreased by more than 50% of pre-clamping value (pathologic SEPs) or when a preoperative CT-scan showed an ischaemic area in the contralateral hemisphere. In some patients the shunt was not inserted because of technical difficulties or because the pathological SEP complex decrease developed when the suture of the arteriotomy was almost complete. RESULTS AND CONCLUSIONS: As the preclamping amplitude (Ab) of N20-P25 was extremely variable, ranging from 0.9 and 7.5 microV, we adopted the ratio: deltaA=(At-Ab)/Ab (At=amplitude measured during clamping every 2 min at time t). Mean decrease of deltaA measured in the whole group ranged between 15% and 20%, but mean deltaA values in patients with pathological SEPs were around 60%. Even patients with positive CT-scans or with a back-pressure lower than 50 mmHg developed a mean deltaA decrease of about 20%. A pathological SEP was present in 50 patients, but developed in only 12 during the clamping trial. An intraluminal shunt was inserted in 22 cases; the other patients received pharmacological treatment with anaesthetic or vasoactive drugs. Among the patients with pathological SEPs, 3 presented postoperative symptoms related to carotid cross-clamping; only 1 of these was shunted but without SEPs normalisation. No patients with normal SEPs developed a postoperative neurological deficit, giving a reliability of 86.7%, a sensitivity of 100% and a specificity of 86.5%.

Ischemia: reperfusion syndrome of the lower limbs.

The ischemia-reperfusion syndrome, first described by Haimovici in 1960, is a severe complication following surgery for acute ischemia. We evaluated the incidence of this complication in 264 patients operated on between 1972 and 1981 (1st group) and compared it with another of 392 patients operated on between 1982 and 1991 (2nd group), our aim being to assess the effects of pharmacological prophyiaxis based on preoperative overhydration followed by an intra-arterial bolus of 250 ml 14/1000 HCO3-, containing 1 g dexamethasone and 2500 I.U. sodium heparin, injected into the femoral artery before suturing the arteriotomy. This regimen was based on the measurement of myoglobin and glutathione levels respectively carried out in two subgroups of 25 patients. The results of experimental ischemia-reperfusion syndromes induced in animal using radical scavengers and membrane-protective compounds were also taken into consideration. Following experimental research on sheep, 5 patients in the second group with very severe ischemia due to aortic occlusion received local dialysis in the extracorporeal circulation using hemodialysis or hemofiltration techniques. Mortality was 6.3% in the first group and 5.4% in the second, while the amputation rate was 3% and 1.8% respectively. The overall incidence of the reperfusion syndrome was 3% in the 1st period and 1.8% in the second. Our findings confirm the protective effect of hyper-hydration, radical scavengers and dexamethasone in the ischemia reperfusion syndrome, and indicate that local hemodialysis is a useful adjunct in very severe ischemia.

Inflammatory aspects in atherosclerotic abdominal aortic aneurysms. A case report.

An important inflammatory reaction was histologically observed in the wall of an abdominal aortic aneurysm in a 42 year-old patient suffering from multifocal atherosclerotic lesions. Histochemical and ultrastructural studies showed an active-stage wall lymphomonoplasmacellular component. The histological appearance and biochemical and microbiological studies excluded specific aortitis, a rheumatic disease or concomitant infectious processes. The morphological relationships between the atherosclerotic lesion and the infiltrate together with the immunophenotyping features of the infiltrate suggest the possibility of a close correlation between the inflammatory process and the atherosclerotic lesion of the wall.

Carotid endarterectomy. Pre- and post-operative monitoring with cerebral SPECT.

In the pre-operative evaluation of carotid endarterectomy, the knowledge of ischemic areas may be helpful to reduce the operative risk. A positive CT scan is often correlated with an increased operative risk. The single photon emission computed tomography (SPECT) allows us to visualize ischemic areas not shown by the CT; these areas are almost always correlated to neurological symptomatology. In patients with positive CT scan, the ischemic areas shown by SPECT are generally larger, because this technique visualize the ischemic area surrounding the cerebral infarct (penumbra). After carotid EA, SPECT is useful to show the hemodynamic modifications induced by this operation. In a series of 15 patients we observed an improvement of the cerebral blood perfusion characterized by the normalization of the blood flow in 7/12 (58%) of the ischemic areas observed pre-operatively), an improvement in 3/12 and a normalization or an improvement in the contralateral hemisphere in 5/7 of the areas. In conclusion SPECT is a useful technique to study the cerebral pathophysiology of both cerebrovascular disease and its surgical treatment.

Effects of the infusion mode on bicarbonate balance in on-line hemodiafiltration.

BACKGROUND: Electrolyte and acid-base balance may be differently affected by the infusion mode in on-line hemodiafiltration (HDF). We studied the effects of the different infusion modes on bicarbonate transport across the dialyzer membrane, and thus on the final bicarbonate balance of the HDF sessions. METHODS: Instantaneous HCO3- transfer across the dialyzer membrane, blood bicarbonate profile and the total balance of the sessions were studied in six dialysis patients under the same operating conditions over 36 HDF sessions, in order to compare the effects of predilution HDF (pre-HDF), postdilution HDF (post-HDF), and mixed HDF on the final bicarbonate balance. RESULTS: The final HCO3- balance was more positive in post-HDF vs pre-HDF (142 +/- 36 vs 99 +/- 41 mmol/session, p<0.05), with a final blood HCO3- concentration of 26.6 +/- 1.0 vs 25.4 +/- 1.1 mmol/L, (p<0.05). Mixed HDF yielded intermediate results (balance: 119 +/- 42 mmol/session, final HCO3- 26.2 (1.2 mmol/L). These differences were seen to result from the increased HCO3- concentration of blood entering the filter in predilution, due to the infused HCO3-, enhancing convective loss and reducing the driving force for diffusive HCO3- gain. CONCLUSIONS: Bicarbonate concentration in dialysate-reinfusate is critical in order to obtain an adequate end of session HCO3- balance in on-line HDF. The predilution method produced the lowest cumulative net HCO3- gain between the three studied infusion modes. Our data suggest that, under the same operating conditions and excluding the effect of ultrafiltration, dialysate HCO3- should be increased by about 2 mmol/L in pre-HDF, and 1 mmol/L in mixed HDF, to yield the same final balance as in post-HDF.

Prescription and surveillance of the acetate-free biofiltration sessions: the bicarbonate cycle.

A computerized system, structured by 4 different models concerning urea depuration, and bicarbonate and sodium handling in acetate-free hemodiafiltration has been conceived for integrated use covering each step of the therapeutic cycle, from a) the prescription of the session to b) its delivery, up to c) the dose-response analysis: the system, now fully developed for the bicarbonate cycle, covers both working areas; the medical one, with a program implemented on a Personal Computer, called Skipper which deals with steps a) and c), and the nursing area, with a program built into the dialytic equipment software. The Skipper program supports the prescription step (a) testing the session schedule by bicarbonate, sodium and urea kinetics. The dialytic equipment, (step(b)) using a different program, on the basis of the scheduled parameters memorizes the end-session plasma bicarbonate level and reacts to any modifications of the parameters regarding blood flow and fluid reinfusion flow suggesting opposite changes in order to reach the scheduled results. Finally (step (c)), the Skipper system statistically evaluates the observed end session bicarbonate plasma level with an expected value with upper and lower confidence bounds obtained by a multiple regression analysis performed on a large population of patients.