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Biomedical subjects

V Parsons

Publications and source records attributed to V Parsons.

At least 73 records · Page 4Linked to original sources
PubMed1982

The influence of hemodialysis fistulas on circulatory dynamics and left ventricular function.

This study was designed to examine the influence of arteriovenous (A-V) fistulas on cardiac output and left ventricular performance in 13 uremic patients on regular hemodialysis. M-mode echocardiography and systolic time intervals were used to derive indices of left ventricular function, and cardiac output was measured by thermodilution. Measurements were performed before and after acute digital occlusion of the A-V fistulas. Occlusion of a single fistula caused systemic vascular resistance and the systolic diameter of the left ventricle to increase from 9.6 +/- 1 to 13.5 +/- 2 units (p less than 0.001) and from 3.2 +/- .3 to 3.4 +/- .4 (p less than 0.05) respectively. The increase in afterload caused a reduction in cardiac output from 11.0 +/- 1 to 9.6 +/- 1 l/min (p less than 0.001) and probably accounted for the minor, though not significant, "deterioration" in the indices of left ventricular function. Bilateral fistula occlusion in 8 patients exaggerated these changes, and the reduction in fractional shortening from 43 +/- 4 to 37 +/- 4% was significant at the 5% level. In two patients with severe left ventricular failure, fistula occlusion caused a more pronounced deterioration in cardiac performance. These results show that acute A-V fistula occlusion effectively lowers cardiac output and is, therefore, likely to be beneficial in the management of high output failure. However, when intrinsic left ventricular disease is the primary etiological factor in heart failure, fistula occlusion is unlikely to be helpful, and may worsen the hemodynamic derangement.

Adult↗
PubMed1981

Congenital hepatic fibrosis and polycystic kidney disease; Role of porta-caval shunting and transplantation in three patients.

Three patients with congenital hepatic fibrosis and childhood-type autosomal recessive polycystic kidney disease are reported. Portal hypertension in two of the children was decompressed surgically by lieno-renal shunting, and the renal failure in two children has been successfully treated with renal transplantation. Prophylactic porta-caval shunting followed by renal transplantation is ideally suited to the sequence of events occurring clinically in the intermediate form of this condition, preventing complications of bleeding from oesophageal varices and hyperplenism. The relationship of congenital hepatic fibrosis with the various forms of polycystic kidney disease is discussed and classified.

Child, Preschool↗
PubMed1981

The influence of 1 alpha-hydroxycholecalciferol on left ventricular function in end-stage renal failure.

This study was designed to assess the influence of 1 alpha-hydroxycholecalciferol on left ventricular function in end-stage renal failure. Twelve patients, all of whom were on regular haemodialysis, were investigated. M-mode echocardiography and systolic time intervals were used to derive indices of left ventricular function. Measurements were performed before and six weeks after treatment with one microgram daily of 1 alpha-hydroxycholecalciferol. Fractional fibre shortening increased from 34.6 to 37.6% (p less than 0.025) and mean velocity of fibre shortening increased from 1.21 to 1.32 circ/sec (p less than 0.01). These changes were associated with a fall in the mean plasma parathyroid hormone concentration from 1883 to 1123ng/L (p less than 0.0025) and a rise in magnesium concentration from 0.89 to 1.06 mmol/L (p less than 0.0025); plasma calcium increased from 2.59 to 2.70mmol/L but this change was not significant. Our results indicate that 1 alpha-hydroxycholecalciferol improves left ventricular function in end-stage renal failure by influencing both the turnover or secretion of parathyroid hormone and the metabolism of calcium and magnesium ions.

Adult↗
PubMed1980

The proteinuria of diabetic nephropathy.

The results of an investigation into the nature of the proteinuria of diabetic nephropathy are described. Proteinuria increases quantitatively with deteriorating renal function but there is no consistent qualitative change; even with small amounts of proteinuria the selectivity may be poor and the proportion of albumin to the total excretion constant. These and other findings are discussed in relation to the possible pathogenesis of the glomerular dysfunction in diabetic nephropathy.

Adult↗
PubMed1980

Platelet protection and heparin sparing with prostacyclin during regular dialysis therapy.

When prostacyclin (5 ng kg-1 min-1) was given during dialysis it enhanced the biological activity of heparin and prevented the activation and consumption of platelets. No adverse effects were observed. The reduction in heparin requirements produced by prostacyclin should make dialysis, safer, particularly for patients at risk of bleeding, while preserving the biocompatibility of the dialysis circuit. It remains to be established whether prevention of platelet activation will confer long-term benefit by inhibiting the prothrombotic state induced by haemodialysis, thereby reducing the risk of atherosclerosis in uraemic patients.

Adult↗
PubMed1980

Triage and the patient with renal failure.

The call for 'triage' as a specific policy for the selection of patients presenting with chronic renal failure, in the light of increasingly limited resources prompted us to question nephrologist on their bases for selection. We discovered no absolute criteria for rejection, but a consensus of opinion against those with additional and complicating factors to their renal disease such as age, hepatitis carriers and mental illness-a bias seen throughout the National Health Service. In this paper we discuss the validity of such criteria, the implications of the currently pragmatic and often covert practice of selection, and in this potentially finite area of demand we question the rationale for the limitation of resources.

Cost-Benefit Analysis↗
PubMed1980

The long-term effect of lowering dialysate magnesium on circulating parathyroid hormone in patients on regular haemodialysis therapy.

Measurement of parathyroid hormone (PTH) in a group of patients on regular dialysis therapy (RDT) showed little acceleration of the development of raised concentrations until the dialysate concentration of magnesium was halved from 0.5 to 0.25 mmol/l. Patients with sustained concentrations of PTH changed less than those who were within the normal range at the outset.

Adult↗
PubMed1980

Arterial hypoxemia during hemodialysis for acute renal failure in mechanically ventilated patients: observations and mechanisms.

Changes in arterial oxygen tension (PaO2) during hemodialysis have been measured in eight patients with acute renal failure who were being mechanically ventilated. Falls in PaO2 under these circumstances (mean = 22.44%, P < 0.05) suggest that loss of carbon dioxide into the dialyzate is not an important cause of arterial hypoxemia during dialysis. White blood count, platelet count and complement levels have also been measured; there is a dissociation between these parameters and falls in PaO2, suggesting that other, unidentified factors are involved in hemodialysis hypoxemia.

Acute Kidney Injury↗
PubMed1980

Risks and benefits of bilateral nephrectomy: an analysis of 134 cases.

In a retrospective survey of 134 patients undergoing bilateral nephrectomy from 1969 to 1980 it was found that the commonest indications were hypertension (60%) and infection/reflux (22%). Operation in hypertensive dialysis patients was followed by a fall in blood pressure in 70% (SE 9%) at one and 3 months while normotensive patients having their kidneys out for other reasons had a 47% (SE 11%) incidence of hypertension at one month and 7 out of 10 were still hypertensive at 3 months. When operation was performed in transplanted patients, 7 of 10 hypertensives had a fall in pressure, one of 6 normotensive persons had an increase, an use of antihypertensive drugs fell from 13/16 to 4 of 16 patients. The mortality was 10.4% (SE 2.6%) overall, the mortality of operations which included an unplanned splenectomy was significantly higher. There were 34 other complications in 25 patients. Complications, but not deaths, were more frequent in operations performed in dialysis patients rather than at the same time as, or after, a transplant. Over 12 years the ratio of bilateral nephrectomy to renal transplant operations has fallen from 8% (1969-1971) to 18% (1978 to present). The decrease is partly due to a fall in the number of operations for hypertension in dialysis patients and may be related to the appearance of beta-blocker and new vasodilator drugs.

Blood Pressure↗