Search PubMed⌕ Search

Biomedical subjects

F Pizzarelli

Publications and source records attributed to F Pizzarelli.

36 records · Page 2Linked to original sources
PubMed1985

The effect of dialysate temperature on haemodialysis leucopenia.

We assessed the influence of dialysate temperature on intra-dialytic leucopenia. Lowering dialysate temperature from 38 degrees C to 20.5 degrees C caused a decrease in the dialysis associated white blood cell reduction from 82 +/- 6 per cent to 32 +/- 19 per cent. The degree of leucopenia bore a highly significant relationship with dialyser blood temperature suggesting that a further lowering of blood temperature (to about 20 degrees C) would almost entirely prevent intra-dialytic leucopenia.

Adult↗
PubMed1985

Influence of blood temperature on vascular stability during hemodialysis and isolated ultrafiltration.

We tested the hypothesis that differing temperature (T) changes in extracorporeal blood circuit might partly account for the difference in vascular stability (VS) between isolated ultrafiltration (UF) and simultaneous UF-hemodialysis (HD). The study was carried out in 6 patients who presented frequent episodes of symptomatic hypotension during the routine dialytic sessions. During simultaneous UF-HD with dialysate T set at 37.5 degrees C (standard HD), blood reentered the patients with a T of about 2 degrees C higher, whereas during isolated UF (standard UF) 2 degrees C lower, than at its exit. These extracorporeal blood T changes were reciprocated by warming the venous line in isolated UF (warm UF) and by setting the dialysate at 34.5 degrees C in simultaneous UF-HD (cold HD). During warm UF mean arterial pressure (MAP) fell and heart rate (HR) increased nearly as much as during standard HD. Vice versa, during cold HD MAP and HR remained nearly as stable as during standard UF. It is concluded that the T changes in blood flowing through the extracorporeal circuit largely account for the differing VS between isolated UF and simultaneous UF-HD.

Adult↗
PubMed1983

Blood temperature and cardiovascular stability in hemofiltration.

Temperature (T) changes in the blood flowing through the extracorporeal circuit markedly affect cardiovascular tolerance to fluid removal during either hemodialysis (HD) and isolated ultrafiltration. In this study we investigated the effect of blood T changes during postdilutional hemofiltration (HF). To this purpose we compared the changes in mean arterial pressure (MAP) and heart rate (HR) during HF and HD carried out at equivalent T of blood in the venous segment of the extracorporeal circuit. Results show that HF entails some heat loss from blood flowing in the extracorporeal circuit; if heat loss is made similar, HD affords nearly as much blood pressure protection as HF does. On the other hand at equivalent heat gain, HF causes nearly as much hypotension as HD does. We conclude that blood T changes in the extracorporeal circuit affect vascular stability (VS) even in HF. The marginal benefit of HF over HD, still observed at equalized T changes, remains to be elucidated.

Blood↗
PubMed1982

Effect of chronic propranolol treatment on bone changes of secondary hyperparathyroidism in dialysis patients.

To assess the effect of long-term propranolol therapy on uremic osteodystrophy, we evaluated retrospectively the biochemical, X-ray, and bone histological changes in 9 dialysed hypertensives who had been on propranolol treatment for periods ranging from 1 to 8 years. The control group included 9 well-matched dialysed uremics never treated with beta-blockers. The two groups did not differ in serum ionized calcium or iPTH levels. The incidence of bone resorption evaluated on X-ray findings and on bone biopsy specimens was of a comparable degree in the two groups. Our data show that propranolol even if started early in the course of renal failure, is of no benefit in preventing uremic bone disease.

Bone Resorption↗
PubMedDate not supplied

Characterization of myocardial tissue in patients undergoing maintenance hemodialysis by quantitative echocardiography.

The uremic state affects myocardial structure, bringing about, among other things, interstitial calcium deposition. Abnormalities of myocardial structure can be assessed quantitatively and noninvasively during life by the analysis of the gray-level distribution of conventional two-dimensional echocardiograms. The aim of this study was to evaluate the role of quantitative echocardiography in providing information on myocardial structure in patients under maintenance hemodialysis and to relate the ultrasonic findings with abnormalities in calcium-phosphate metabolism. Forty patients undergoing dialysis without abnormalities in left ventricular regional and global function and 17 hypertensive patients with comparable left ventricular hypertrophy were studied. The distribution of the gray levels within a region of interest in the interventricular septum was analyzed off-line by an array processor-based computer. Compared with hypertensive patients, patients undergoing dialysis showed a greater myocardial echogenicity (mean 92 +/- 20 versus 72 +/- 15; p = 0.004) and a reduced homogeneity of distribution of gray levels (entropy 4.5 +/- 0.2 versus 4.2 +/- 0.2, p < 0.01; uniformity 0.010 +/- 0.003 versus 0.020 +/- 0.004, p < 0.005). In the same patients, a significant negative linear relation was found between entropy and calcium-phosphate product (r = -0.66; p = 0.001). Quantitative analysis of conventional two-dimensional echocardiograms allows the detection of a pathologic myocardial structure in patients under maintenance hemodialysis with normal left ventricular function. These abnormalities are related to disorders of calcium-phosphate metabolism and bear no relationship to the degree of left ventricular hypertrophy.

Adult↗
PubMedDate not supplied

[On-line hemodiafiltration without acetate].

PURPOSE: The suitably filtered dialysate which is currently reinfused during on-line hemodiafiltration (HDF-OL) contains bicarbonate and small doses of acetate. The trend of acetataemia During "forced" convective treatments has never been studied. The gain in acetate secondary to the considerable quantities of fluids infused might have clinical significance in relation to the well-known side effects of this anion. METHODS: In this pilot study 12 patients underwent HDF-OL with reinfusion in predilution of 40 L of substitution fluids containing or not 3 mmol/L of acetate. Apart from this variable, all the other treatment parameters were the same in both procedures. The treatments were carried out in two short consecutive intervals in a random sequence. RESULTS: During HDF-OL the use of dialysate containing small doses of acetate is associated with levels of acetataemia 5-6 times higher compared to the basal. HDF-OL without acetate cancels out this increase. The acetate gained by the patients is significant, on average 75 mmol, and accounts for over 1/3 of the global base gain. Consequently, the bicarbonataemia levels at the end of treatment are significantly higher in HDF-OL with acetate than in the treatment without. Two hours after the end of the treatments the IL-6 levels tend to grow in both methods, but numerically less in HDF-OL without acetate; the difference verges on meaningfulness. CONCLUSIONS: The acetate gain is significant during forced convective treatments carried out with standard dialysate. This acetate gain can trigger cytokinin activation. These events are cancelled out by eliminating the acetate from the dialysate. The absence of this anion will be compensated with appropriate increases in the concentration of bicarbonate in the dialysis fluid.

Acetates↗
PubMedDate not supplied

[Guidelines on water and solutions for dialysis. Italian Society of Nephrology].

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.

Colony Count, Microbial↗
PubMedDate not supplied

[From dialysate temperature to thermal balance].

The observations concerning the role of temperature in cardiovascular (CV) stability date back to the early 1980s. Since then, many studies have corroborated the original findings on the hemodynamic benefits of what is known as 'cold' as opposed to 'warm' or standard hemodialysis (HD). While the assumptions and conclusions remain fully valid, more recent experience has led to a review of the way the treatments have been defined. The fact that the patient gains or loses heat is not only the consequence of dialysis fluid temperature, but is the result of the interrelationships between dialysis-related factors and patient characteristics. Among the former, blood flow, arterovenous temperature difference in the extracorporeal blood, length and layout of the hematic lines, environmental temperature, and a possible cytokine-mediated pyrogenic effect are all factors that, directly or indirectly, can decisively influence the thermal balance of the dialysis session. Among the latter, the greater the ultrafiltration (UF) rate the greater the buildup of body heat. Finally, there is a considerable variability in body temperature within and between individual uremic patients, and it is especially the subgroup of hypothermic patients who benefit from cold dialysis. These considerations have led to the conclusion that the thermal balance of the dialytic treatment should be tailored to the specific characteristics of the patient and should be adjusted automatically in the course of the dialytic treatment. On these grounds, it is preferable to define thermal variations induced by HD based on physiological effects induced in the patient. Therefore, dialytic treatments can be defined as isothermic, hypo or hyperthermic, depending on the variations in body temperature produced. Isothermic HD combines better benefits in terms of CV stability with fewer unwanted side effects. There are several commonly used therapies of symptomatic hypotension, but they have not been directly compared in the same group of patients. Comparison studies could offer a rational and a most effective approach to treating symptomatic hypotension.

Body Temperature↗
PubMedDate not supplied

[Natural history of HCV infection and risk of death in a cohort of patients on long-term hemodialysis].

BACKGROUND: HCV infection represents the major cause of chronic liver disease in hemodialysis and renal transplant patients. The clinical course of liver disease in hemodialysis patients is generally asymptomatic. Only few studies describe the natural history of HCV infection in haemodialysis patients, showing an association between HCV infections and poor survival. METHODS: A prospective cohort study of our haemodialysis population was conducted to define the natural history of HCV infection and its relation to mortality. 77 patients on haemodialysis were enrolled, 24 (31%) of whom were anti-HCV and 53 (69%) anti-HCV-negative. RESULTS: The HCV-RNA was positive in 18 of the 24 anti-HCV-positive subjects (75%). None of the anti-HCV-negative subjects was HCV-RNA-positive. Eight of the 18 HCV-RNA-positive patients (40%) developed cirrhosis with portal hypertension and ascites within 7 years after the first increase of GPT. Seven of these died, nobody developed hepatocarcinoma (HCC). During 58+/-37-follow-up months mortality rate was higher among anti-HCV-positive patients than among anti-HCV-negative. Besides, the 6 deaths occurred only among anti-HCV-positive and HCV-RNA-positive patients. CONCLUSION: in our haemodialysis patient population the presence of antibodies anti-HCV and HCV-RNA is associated with an increased risk of developing liver cirrhosis and of death, in comparison to anti-HCV-negative patients. Our data show that anti-HCV-positive patients have an accelerated course towards chronic hepatopathy and cirrhosis.

Aged↗