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F Pizzarelli

Publications and source records attributed to F Pizzarelli.

At least 19 recordsLinked to original sources
PubMed1995

Non-invasive monitoring of hemodynamic parameters during hemodialysis.

We studied in 13 hemodialysis patients intradialytic variations of blood volume (BV) and cardiac output, by means of non-invasive methods. We found a weak correlation, r 0.2 or less, between BV variations and intradialysis blood pressure variations. The sensitivity of the former in describing the variations of the latter was only 32%. During the 30 min preceeding the hypothensive crisis the percent BV variations did not show any predictive trend. On the contrary, refilling increased as blood pressure dropped and a weak inverse relation (r -0.35) was found between these two parameters. Unstable patients had predialytic blood volume values significantly lower than stable ones and comparable to healthy subjects. On the contrary, the correlation between percent variations of cardiac output index and MAP was 0.68 with a sensitivity and specificity of 90% and 59%, respectively. Unfortunately these promising results were obtained only with an estimate of cardiac output obtained by echocardiography and not by transthoracic impedance cardiography, which is much more feasible than the former as on-line monitoring of cardiac output. On-line monitoring of hemodynamic parameters is an appealing but still unsolved task.

Aged↗
PubMed1995

Thermal balance and dialysis hypotension.

Many studies have confirmed our original observation that dialysate T set at about 35 degrees C affords a better hemodynamic protection than the standard dialysate T of 37-38 degrees C. In this review we present some new data on the hemodynamic mechanism of the protective effect of cold dialysis on blood pressure. The study was based on serial assessment of the percent changes occurring during dialysis treatment in estimated stroke volume (aortic blood flow determined by Doppler echocardiography), blood volume (hemoglobinometry), arterial pressure (Dynamap), and heart rate (ECG), from which cardiac output (CO) indexes and total peripheral vascular resistances (TPVR) were derived. Of the 14 pts studied, 7 showed a drop in mean arterial pressure (MAP) of 25% or greater during standard dialysis (unstable patients). Compared with the 7 patients having more stable intradialysis MAP, unstable pts showed greater reduction in CO which was disproportionately greater than the reduction in blood volume, and a paradoxical decrease in TPVR, the difference being highly significant (p < 0.01 for both changes). When crossed-over to cold dialysis, along with a significantly lower reduction in MAP (p < 0.01) the unstable pts showed a lower decrease in CO which paralleled the reduction in blood volume, and an increase in TPVR. These changes were highly significant (p < 0.01). Data suggest that dialysis hypotension is characterized by an impaired venous return, probably due to the peripheral blood pooling (increased ratio between the 'unstressed' and 'stressed' blood volume) associated with the decrease in TPVR. Exposure of extracorporeal blood to cold dialysate favours the venous return to the heart by increasing TPVR and the 'stressed' blood volume.

Blood Pressure↗
PubMed1993

Parathyroidectomy and blood pressure in hemodialysis patients.

To assess whether parathyroidectomy (PTx) affects blood pressure (BP) in hemodialysis (HD) patients, we studied 11 uremics on HD treatment for 8.2 +/- 0.9 years who underwent successful PTx. As the control group, we selected 11 HD patients not submitted to PTx, matched with the study group for sex, age, years on HD, dialysis procedure and BP values. In the controls, BP and body weight did not change during the 2 years of observation. In the patients, BP remained stable in the year before PTx. PTx caused a progressive reduction in BP in 7 of the 11 patients. The fall was significant from the 3rd quarter onward (mean BP values before PTx: 139/82 mm Hg, 1 year after PTx: 122/75 mm Hg). The magnitude of the hypotensive effect of PTx was related to the pre-PTx systolic BP value (r = -0.70, p = 0.016). PTx also caused a significant progressive increase in body weight (1.56 +/- 0.57 kg 1 year after PTx). In conclusion, PTx causes BP fall in HD patients regardless of whether their preintervention values are normal or increased. The BP reduction occurs in concomitance with a consistent increase in body weight. BP variations are clinically relevant and may be related to the post-PTx calcium efflux from the vessel wall.

Alkaline Phosphatase↗
PubMed1992

Hepatitis B vaccination in dialysis patients and nutritional status.

35 dialysis patients underwent anti-HBV vaccination. We classified patients in responders or non-responders using an anti-HBs titer of 50 UI/l as the discriminating serum level and tried to assess whether the antibody response bears any relationship with the nutritional status. 26 patients (74%) reached the target atb titer, which was maintained during follow-up (average 360 UI/l). The weak response in the other 9, with values never exceeding 20 UI/l, was short-lived. Anthropometric and impedenziometric parameters were higher in responders than in nonresponders, but the difference did not reach statistical significance. We conclude that the atb titer which discriminates uremics in responders or not must be greater than 50 UI/l and that the nutritional status may interfere with the seroconversion rate, but this conclusion needs to be validated in a wider population.

Adult↗
PubMed1988

Aluminum bone content in dialysis osteodystrophy with secondary hyperparathyroidism.

To assess whether parathyroid hormone (PTH) has any effect on bone aluminium (A1) accumulation, we evaluated the relationship between bone quantitative histomorphometry and bone A1 content in 25 dialysis patients with clinical features of secondary hyperparathyroidism. By means of bone biopsy, patients were classified as showing predominant hyperparathyroidism in 17 cases and mixed lesions in 8. The A1 burden was low, judging from the dialysate A1 and the oral A1 assumption. Bone A1 content and serum A1 levels were higher than normal in both groups, particularly so in the patients with predominant hyperparathyroidism. Significant positive correlations were found between bone indexes of hyperparathyroidism and bone A1 content. Moreover, bone and serum A1 concentrations were directly related. Aluminium staining appeared faintly positive only in a minority of bone samples, and was mainly localized at the neutral bone surfaces. We conclude that in dialysis osteodystrophies with features of secondary hyperparathyroidism and in a clinical setting characterized by low-grade A1 burden, PTH may favour A1 accumulation into the bone.

Adult↗
PubMed1987

Effect of chronic administration of ammonium sulfate on phosphatic stone recurrence.

Urine alkalinization favours the formation of calcium phosphate (CaP) and struvite stones. In this retrospective study we analyze the effect of chronic urinary acidification on phosphatic stone recurrence. Twenty-four patients with CaP-struvite recurrent stones and persistently high urinary pH were divided in two groups: group A, 11 patients who failed to lower the urinary pH below 5.5 during a standard acid load test: group B, 13 patients with preserved acidification power. Ammonium sulfate 2-3 g/day was given for 4.7 and 6.5 years to groups A and B, respectively. A persistent reduction in urinary pH, relative saturation for CaP and stone formation rate was observed in both groups. The treatment did not cause systemic acidosis as long as renal function remained normal. Urinary daily excretion of Ca and P as well as their renal tubular handling did not change with time. Results suggest acidifying agents might be useful in preventing recurrence of CaP-struvite stones even in the presence of a mild acidification defect and encourage undertaking properly controlled prospective trials.

Adult↗
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↗