Fluid state and blood pressure control in patients treated with long and short haemodialysis.

BACKGROUND: Patients treated at the haemodialysis (HD) centre in Tassin, France have been reported to have superior survival and blood pressure (BP) control. This control has been ascribed to maintenance of an adequate fluid state, antihypertensive drugs being required in < 5% of the patients, although it could not be excluded that a high dose of HD regarding removal of uraemic toxins might also have been of value. METHODS: The aim of the study was to assess the fluid state and BP in normotensive patients on long HD (8 h) in Tassin (group TN) using bioimpedance to measure extracellular volume (ECV), ultrasound for determining the inferior vena cava diameter (IVCD), and 'on-line' monitoring of the change in blood volume (BV), and to compare them with normotensive (group SN) and hypertensive (group SH) patients on short HD (3-5 h) at centres in Sweden. ECV was normalized (ECVn) by arbitrarily setting the median ECV (in % of body weight) in SN patients at 100% for each gender, recalculating the individual values and combining the results for male and female patients in each group. RESULTS: The dose of HD (Kt/V urea) was higher for TN patients than for Swedish patients who had a similar Kt/V, whether hypertensive or not. SH patients had significantly higher ECVn and IVCD than TN and SN patients. TN and SN patients did not differ significantly regarding ECVn and IVCD before and after HD. However, in a subgroup of eight TN patients, ECVn was below the range of that in SH and SN patients, due to obesity with a high body mass index. Another subgroup of 14 TN patients had a higher ECVn than most of the SN patients and also higher than the median ECVn in the SH group, without any difference in body mass index, but they were nevertheless normotensive. The fall in BV was greater in SN than in TN patients, presumably due to a higher ultrafiltration rate in SN patients. However, SH patients had a smaller change in BV than SN patients, presumably because their state of overhydration facilitated refilling of BV from the interstitial fluid. CONCLUSIONS: Normotension can be achieved independently of the duration and dose (Kt/V urea) of HD, if the control of post-dialysis ECV is adequate. However, this is more difficult to achieve with short than with more prolonged HD during which the ultrafiltration rate is lower, BV changes are smaller and intradialysis symptoms less frequent. The results in the subgroup of patients with high ECVn at Tassin suggest that normotension may also be achieved in patients with fluid overload provided that the dialysis time is long enough to ensure more efficient removal of one or more vasoactive factors that cause or contribute to hypertension.

A critical evaluation of ultrasound measurement of inferior vena cava diameter in assessing dry weight in normotensive and hypertensive hemodialysis patients.

The utility of measurement of the inferior vena cava diameter (IVCD) with ultrasound for the assessment of fluid status and posthemodialysis dry weight was studied in 35 hemodialysis (HD) patients, 17 with and 18 without hypertension. In 17 patients (group A), IVCD was measured before and 35 to 40 minutes after HD, pre-HD blood volume (BV) was measured with radiolabeled albumin and post-HD BV was calculated from the change in hematocrit. In 18 patients (group B), IVCD was measured repeatedly during HD and 2 hours after HD. Changes in BV were recorded by monitoring of the hematocrit "on line." Body weight, blood pressure (BP), BV, and IVCD decreased in the entire population. In group A, BV was significantly larger in the hypertensive patients than in the normotensive patients, and it was correlated with the mean BP before and after HD. In the whole population, IVCD was larger in the hypertensive than in the normotensive patients before and after HD. These results confirm that extracellular fluid overload plays an important role in the pathogenesis of dialysis-associated hypertension. In group B, BV and IVCD decreased in parallel during HD and increased during 2 hours after HD due to refilling of the intravascular space, indicating that changes in IVCD reflect changes in BV. In 8 patients studied twice, IVCD increased much more after a 3-hour HD session than after a 6-hour session. At the end of HD, several patients had IVCD below the reference range but IVCD increased during the following 1 to 2 hours, in some patients to values above the reference range. IVCD measured at the end or shortly after HD may therefore be misleading in assessing dry weight.

Multifrequency bioimpedance in assessment of dry weight in haemodialysis.

The use of multifrequency bioimpedance (MFB) for determination of dry weight (DW) in haemodialysis (HD) patients was evaluated in three studies. In Study 1, the fluid state [total body water (TBW) and extracellular volume (ECV)] was measured by MFB in 82 normotensive patients. 41 hypertensive patients and in 30 healthy subjects. TBW and ECV were expressed as per cent of body weight (BW). In Study 2, DW of five hypertensive HD patients was gradually decreased during 3 months and ECV (MFB) and blood pressure (48 h ambulatory blood pressure monitoring) were measured at the beginning and end of study. In Study 3, we measured the fluid status repeatedly by MFB and the diameter of the inferior vena cava (DIVC) by ultrasound before, during and 2 h post-HD. In Study 1, the hypertensive patients had significantly greater TBW (P < 0.05) than the normotensive patients before (50.3 +/- 6.5% vs 47.6 +/- 5.8%) and after HD (48.8 +/- 7.8% vs 45.7 +/- 6.4%) and ECV (P < 0.001) before (29.4 +/- 3.6% vs 26.8 +/- 3.5%) and after HD (27.0 +/- 4.0% vs 24.6 +/- 3.5%), Post-HD ECV in the normotensive patients was similar to that in the healthy subjects. In Study 2, more efficient ultrafiltration resulted in reduction of BW and ECV along with a decrease in blood pressure and need for antihypertensive medication. In Study 3, both ECV and DIVC decreased following the removal of fluid during HD. ECV maintained stable values during the post-HD period, unlike DIVC which increased significantly (P < 0.005) due to refilling from the interstitial space. We conclude that MFB is an appropriate non-invasive method for DW determination, which is highly reproducible and technically simple to use.

Septic shock induced by group A streptococcal infection: clinical and therapeutic aspects.

During 1988 and 1989 > 500 cases of serious group A streptococcal infections were reported in Sweden, many with a fatal outcome. We report here on 11 consecutive patients with septic preshock/shock and multiorgan failure, including acute renal failure. 10 had verified group A streptococci (GAS) serotype T1M1 infections while 1 patient was culture negative but with clinical signs of severe infection and serological evidence of GAS infection. Presenting symptoms were high fever, relative bradycardia, edema and renal failure. In all patients the condition deteriorated despite conventional treatment including volume substitution and antibiotics. Systolic blood pressure was transiently < 80 mmHg in 10 patients and 9 of them needed infusion of inotropic agents to avoid fatal circulatory shock. In 9 patients respiratory aid was instituted and 7 were dialysed. Plasma exchange was performed in 7, while the remaining 4 received transfusions with blood and plasma without plasma exchange. 10 patients improved and were discharged within 8 weeks. One woman died within 2 days after admission to the hospital. Renal function recovered in all survivors, with a follow-up serum creatinine < 80 mumol/l. The complicated clinical picture in these patients with many simultaneous therapeutic events confounds the interpretation of the effect of single actions. The favourable outcome in these severely ill patients suggests that potent inotropic agents, immunoglobulin therapy and plasma exchange might be beneficial in severe streptococcal disease when conventional treatment fails.

Effects on serum parathyroid hormone of intravenous treatment with alphacalcidol in patients on chronic hemodialysis.

Secondary hyperparathyroidism is common in chronic renal failure and is due to inadequate synthesis of calcitriol, the active metabolite of vitamin D. Intravenous administration of alphacalcidol, a synthetic analogue which is metabolized to calcitriol, was given during 12 weeks to 51 patients on chronic hemodialysis in doses between 1 and 4 micrograms/dialysis session. The treatment caused a modest rise, by 0.25 mmol/l, in serum calcium but a 60% reduction of intact serum PTH concentrations. Most patients acquired normal PTH values and hypercalcemia was easily avoided by dose adjustments. There was a significant reduction in serum PTH within the 1st week before the serum calcium concentrations were increased, but after that time the induced suppression of PTH was correlated to the induced rise in serum calcium. These observations are compatible with the view that calcitriol exerts both a direct inhibition of PTH release and increases the gland's sensitivity to calcium. The major implication of the study is that intravenous treatment with alphacalcidol is of great clinical value since it is easy to administer and provides suppression of hypersecretion of PTH with few side effects.

Membrane bound IgG on erythroblasts in pure red cell aplasia following thymectomy. A case report.

A case of pure red cell aplasia appearing 6 months following thymectomy is reported in a 43-year-old man. Immunofluorescence studies of the patient's bone marrow have demonstrated the presence of membrane-bound IgG on the majority of erythroblasts and some mature erythrocytes. It is suggested that the IgG represents anti-erythroid autoantibodies. The number of Ig-bearing lymphocytes in peripheral blood was decreased as was the level of immunoglobulins indicating a B-lymphocyte deficiency. T-lymphocyte functions were without remarks. The patient was initially treated with corticosteroids and oxymetholone. He responded well to this therapy but relapsed 9 month later. Cyclophosphamide treatment was started and followed by a complete haematologic remission.