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Biomedical subjects

S R Acchiardo

Publications and source records attributed to S R Acchiardo.

49 records · Page 3Linked to original sources

Folic acid dosage for chronic hemodialysis patients.

The doses of folic acid, necessary to avoid folic acid deficiency in patients being maintained on hemodialysis, have been estimated to be between 1 and 5 mg daily. To more precisely define an adequate dose of folic acid, 6 anephric patients were studied. The patients were maintained on hemodialysis and received, in a crossover fashion, 1 mg and 5 mg of folic acid for 3 wk. In a second crossover study, 3 anephric patients were first maintained on 0 and then on 1 mg of folic acid after each dialysis for 3 wk periods. Pre- and postdialysis folic acid blood levels were measured and dialyzer clearances of folic acid were determined. The results of this study support the conclusion of the Food and Drug Administration report suggesting that daily doses of 1 mg of folic acid are adequate to sustain therapeutic folate levels. The data further indicate that the administration of 1 mg of folic acid after each dialysis, rather than 1 mg of folic acid daily, can provide adequate folate.

Administration, Oral↗

Treatment of patients with severe hypertension by inhibition of angiotensin-converting enzyme.

1. The results of the administration of the nona-peptide inhibitor (SQ 20,881) of the enzymatic conversion of angiotensin I into angiotensin II in twelve severe hypertensive patients are presented. 2. Administration of the compound was associated with a fall in blood pressure in ten of twelve patients. 3. Four patients had a normal plasma renin activity (PRA) with a range of 1.6-3.7 ng h-1 ml-1 and eight patients had a high PRA with a range of 5.0-74 ng h-1 ml-1. Two of the patients with normal PRA had no fall in blood pressure despite receiving 2 mg/kg of the compound. Two patients with normal PRA, however, did respond, thus indicating that a high PRA is not necessary for a response to the inhibitor compound. 4. It was found that haemodialysis or diuresis with frusemide enhanced the blood pressure response to the compound. 5. The presence of a measured low total blood volume was found to be associated with an exaggerated fall in blood pressure to a small dose of compound (0.125 mg/kg) in one patient.

Blood Pressure↗

Malignant hypertension due to musculo-mucoid intimal hyperplasia of intrarenal arteries. Absence of renal fibrinoid necrosis.

Severe essential hypertension in a subset of American black subjects is associated with marked stenosis of interlobular arteries and arterioles of the kidneys, observed by renal biopsy and binephrectomy specimens. The interlobular arterial stenosis is caused by marked thickening of the intima due mainly to the presence of smooth muscle cells, basement membrane material, and acid mucopolysaccharide. Because of this makeup, we propose the term "musculo-mucoid intimal hyperplasia" for this lesion. The media of these arteries appears maximally dilated, and by electron microscope displays degenerative changes of the smooth muscle cells. The arterioles are thickened, due mainly to hyalinization, but also due to the musculo-mucoid change (onionskin effect). The smooth muscle cells are degenerated and atrophic. These patients do not exhibit fibrinoid necrosis of the arteries, arterioles, and glomeruli, presumably because of the rapidity of the development of the arterial stenotic lesion. Accordingly, the glomeruli are destroyed by ischemia, and there is no evidence of glomerulitis (no "Kombinations" form of Fahr). A unifying hypothesis concerning renal hypertensive arterial disease is suggested by these studies. This hypothesis places the main emphasis for all the morphological expressions of the intrinsic visceral vasculature on changes involving the main functional unit of the vessel wall, the medical smooth muscle.

Acute Kidney Injury↗

Liquid and solid potassium chloride: bioavailability and safety.

Studies have suggested that microencapsulated preparations of potassium chloride may pose less risk to the upper gastrointestinal mucosa than the currently available wax-matrix preparations. Based on our own clinical experience and data available from the literature, we have concluded that (1) liquid and slow-release preparations of potassium chloride are safe and effective when used appropriately and (2) at present there is no conclusive evidence to suggest that lesions of the upper gastrointestinal tract are more prevalent with one slow-release preparation than with another.

Biological Availability↗

Are high flux dialysis and erythropoietin treatment in a collision course?

Twenty patients treated with human recombinant erythropoietin (EPO) for 9 months were studied. The patients were randomly allocated to high flux (HF) or conventional dialysis (CD). Patients on HF used the F-60 or F-80 dialyzer, with a polysulfone membrane; QB: 470 ml/min; QD: 800 ml/min; t: 127 min; Kt/V: 1.01. Conventional dialysis patients used regenerated cellulosic membranes; QB: 297 ml/min; QD: 500 ml/min; t: 193 min; Kt/V: 1.05. Mean dose of EPO was 103 U/kg for HF patients and 112.4 U/kg for patients on CD. At 9 months, no significant differences were observed in HCT (HF 33.6% vs. CD 33.2%), BUN, serum creatinine, potassium, or phosphorus. Hemoconcentration during dialysis was 12% for HF and 17% for CD. Urea clearance decreased 7% for HF and 9% for CD, while clearance of creatinine, potassium, and phosphorus decreased between 14 and 18% with both treatments. Heparin requirements increased 10% in HF and 16% in CD. Hypertension was similar in both groups. One HF patient withdrew from the study because of hypertension and one HF patient had seizures related to hypertension. Vascular access clotting or hospitalizations were no different. High flux dialysis patients on EPO over a 9 month period did not have any catastrophic complications when HCT was maintained between 30 and 35%.

Adult↗

Inadequate dialysis increases gross mortality rate.

The authors correlated the dialysis parameters of 613 patients on hemodialysis with their morbidity and mortality. Dialysis prescription (Kt/V) was calculated according to the dialyzer, blood flow, and dialysis time. Dialysis delivered was calculated using percentage urea reduction (PUR). Eighty patients who underwent dialysis in three units had only predialysis blood urea nitrogen (BUN) values available. Mean predialysis BUN was between 58 +/- 16 and 83 +/- 17 mg/dl. Patients with predialysis BUN > 100 mg/dl ranged from 0-22%, and those with predialysis BUN < 50 mg/dl ranged from 0-41%. Kt/V prescribed was between 0.45 and 1.75. Mean dialysis time was 191 +/- 28 min, and blood flow was 327 +/- 48 ml/min. Delivered dialysis was 78% of that prescribed. Patients who had a prescribed or delivered Kt/V < 0.8 varied from 0-44.8%. Mortality rate per year was between 11.3% and 54%. The authors attributed elevated BUN to increased protein intake or inadequate dialysis. Low BUNs may have been due to residual renal function or malnutrition. None of the dialysis parameters correlated with mortality rate except for a Kt/V < 0.8 (p < 0.001) that was directly related to mortality rate. Inadequate dialysis increases mortality rate.

Blood Flow Velocity↗

Nonpercutaneous transmission of hepatitis B to the families of hemodialysis patients.

1. Fifteen percent of the hemodialysis patients were carriers of HBsAg. 2. Thirty-one percent of the carriers' contacts had HBAb in their blood. 3. Spouse of carriers had a higher prevalence of positive HBAb than any other family contact. 4. Only 6 out of 17 patients transmitted the virus to their contacts. 5. None of the contacts of the staff, with history of hepatitis B, had evidence of hepatitis. 6. Contacts with positive HBAb had no evidence of active liver disease.

Adult↗

Is Na+ modeling necessary in high flux dialysis?

One important pathogenic factor in dialysis hypotension is the drop in plasma osmolality. Increasing the dialysate Na+ concentration decreases hypotensive episodes. The authors studied 39 patients being treated with high flux dialysis. During a 9 week period, the patients were on a standard Na+ dialysate (Na+ = 140 meq/L) basal period (B); 9% (Na+ = 149 meq/L) linear (L); step drop (S); and exponential drop (E). The Na+ program was changed weekly at random. The results obtained with the three Na+ modeling programs were similar. We compared the periods with and without Na+ modeling: no differences were found in weight gained interdialysis, mean blood pressure predialysis and postdialysis, and hemoconcentration. Serum Na+ levels were significantly higher predialysis and postdialysis for those patients on Na+ modeling. Hypotensive episodes and cramps decreased 50% with Na+ modeling. The amount of hypertonic and normal saline given during dialysis was markedly reduced. Na+ modeling should always be used in patients being maintained on high flux dialysis.

Adult↗

Is hematologic response to iron and erythropoietin in hemodialysis patients affected by other factors?

Multiple factors have been implicated in the hematologic response to erythropoietin (EPO). The authors studied 54 hemodialysis patients; 44 received 1.5 g of iron intravenously, 16 received oral iron for 12 weeks, and 24 were treated with EPO. Some patients received these treatments in sequence. The factors evaluated were serum albumin, protein catabolic rate, serologic evidence of hepatitis B or C, parathormone (PTH), and aluminum levels. Red cell production was expressed as milliliters of red blood cell increase per day per kilogram of body weight. For patients receiving EPO, hematologic response was normalized to 50 U/kg/dialysis. Of the patients on oral iron, 31% had a good response (hematocrit greater than or equal to 30%). Of the patients who received iron intravenously, 50% had a good response (hematocrit greater than or equal to 30%). All patients treated with EPO responded well, except for one patient who did not respond to doses of EPO up to 200 U/kg/dialysis. The response to intravenous iron dextran was more rapid than the response to oral iron or EPO. Nutritional factors (serum albumin and protein catabolic rate), serologic evidence of hepatitis, elevated PTH levels, or elevated aluminum levels did not significantly affect the response to iron supplementation or EPO treatment.

Administration, Oral↗

Morbidity and mortality in hemodialysis patients.

Increase in mortality in hemodialysis patients in the United States is a rising concern. In this study, the annual mortality rate from 1981 to 1989 was determined and the morbidity and mortality of 136 patients dialyzed during 1988 was analyzed. All patients were followed with urea kinetics (UK). Patients were divided according to NCDS mapping of BUN and protein catabolic rate (pcr): Group 1, inadequate protein intake (n = 28); Group 2, adequate dialysis (n = 51); Group 3, excessive dialysis (n = 28); Group 4, undefined domain (n = 13); and Group 5, transitional domain (n = 16). The UK parameters measured were midweek predialysis BUN, pcr, and Kt/V. Group 1 by definition had the lowest pcr (0.7 g/kg/day vs. greater than 1.0 in the other groups). Patients in Group 1 had significantly lower BUN, creatinine, hematocrit, and serum albumin. Results of all other laboratory tests were not significantly different. Numbers of hospitalizations and days in the hospital were higher in Group 1. Causes of hospitalization were similar in all groups. Mortality rate was 8% in Group 1 vs. 4.4% in Group 2. Dialysis prescription using UK has maintained the annual mortality rate at about 14% for the past nine years.

Adult↗