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Thirteen patients with chronic renal insufficiency who had been transferred from haemodialysis to haemofiltration treatment because of dialysis and drug resistant hypertension (10 with high plasma renin activity) showed normalisation of blood pressure during a treatment period of 8 months, after which only one patient required antihypertensive drug therapy. During the first period blood pressure drop paralleled body weight loss and after 3--4 weeks blood pressure remained normal in spite of an increase in body weight. In the course of the second phase the effect of fluid withdrawal on blood pressure was directly proportional to the blood pressure at the beginning of the procedure. Adaptation of baroreceptor function must be assumed. In contrast to haemodialysis, haemofiltration did not influence the inulin space. Because of the reduced removal of small molecular substances compared with haemodialysis, extracellular osmolarity was kept stable during haemofiltration. Withdrawal of even large amounts of fluid was sustained without collapse reactions or signs of orthostatic dysregulation.
Proc Eur Dial Transplant Assoc 1977
PMID:Treatment of severe hypertension in chronic renal failure by haemofiltration. 60 Sep 48

Continuous recording of beat-to-beat changes in haemodynamic parameters such as arterial pressure, heart rate, stroke volume, cardiac output, and total peripheral resistance, was done in 52 uraemic patients. The study was performed during the haemodialysis session, using a system combining a personal computer, an arterial pressure recorder, and an electrical bioimpedance cardiography monitor. Forty-six episodes of dialysis-induced hypotension occurred in 26 patients. Systolic arterial pressure and total peripheral resistance decreased by -39.3 +/- 2% and -36.3 +/- 4% respectively during acute hypotension; in contrast, there was an increase in cardiac output (+13.9 +/- 6.7%), while heart rate and stroke volume did not change significantly. It was possible to distinguish two types of collapse on the basis of heart rate behaviour: the classic 'tachycardiac' collapse with heart rate increase and stroke volume decrease, and the so-called 'bradycardiac' collapse with a paradoxical reduction in heart rate and an increase in stroke volume. 'Bradycardiac' collapses were observed in 54% of the cases. The administration of atropine in one patient resulted in an immediate increase in heart rate. The development of bradycardia and hypotension during haemodialysis seems to be related to a sudden parasympathetic vagal overactivity and could be attributed to the Bezold-Jarish reflex.
Nephrol Dial Transplant 1990
PMID:A haemodynamic study of hypotension during haemodialysis using electrical bioimpedance cardiography. 212 48

Using echography, the diameter of the inferior vena cava (IVC) and its decrease on deep inspiration (collapse index) were evaluated in haemodialysis patients. The diameter of the IVC was expressed as an index to the body surface area (VCD) in mm/m2. Non-linear regression analysis in predicting mean right atrial pressure by VCD (mm/m2) and collapse index revealed a good correlation (r = 0.92; P less than 0.001) in both measurements. These results indicate that the IVC indices can be used as a parameter for both high and low filling pressures. Over-hydration (mean right atrial pressure greater than 7 mmHg) was defined as a collapse index of less than 40% and a VCD of more than 11.5 mm/m2, and underhydration (mean right atrial pressure less than 3 mmHg) as a VCD of less than 8 mm/m2 and collapse index of above 75%. In 22 patients in whom dry weight was determined on clinical grounds, only six had a correct dry weight according to IVC indices. Reliability of IVC indices for estimation of body fluid status was proved by the fact that during haemodialysis with fluid removal, postdialysis underhydrated patients according to IVC indices showed a decrease of mean arterial pressure and stroke volume, and an increase of heart rate. No such changes were observed in postdialysis normovolaemic and hypervolaemic patients, according to the vena cava indices. Furthermore, blood volume in normo- and hypervolaemic patients decreased much less than in hypovolaemic patients, despite the same amount of ultrafiltration. Total blood volume (ml/m2) and VCD (mm/m2) correlated significantly (r = 0.61; P less than 0.001), whereas there was no significant correlation between collapse index and blood volume.(ABSTRACT TRUNCATED AT 250 WORDS)
Nephrol Dial Transplant 1989
PMID:Echography of the inferior vena cava is a simple and reliable tool for estimation of 'dry weight' in haemodialysis patients. 211 57

The relationship between inferior vena cava diameter (VCD), collapse-index (CI) determined by echography, and alpha-human atrial natriuretic peptide (alpha-h-ANP) concentrations were studied in 19 chronic haemodialysis patients. A significant correlation was found between VCD and alpha-h-ANP before dialysis (r = 0.78; P less than 0.0001). No such correlation was found between CI, left atrial diameter and left ventricular end-diastolic diameter, and alpha-h-ANP values. In nine patients who according to vena cava indices were hypervolaemic before dialysis (group I), alpha-h-ANP concentrations were significantly greater than in ten normo- or hypovolaemic patients (group II): 392.8 +/- 134.1 pg/ml and 168.0 +/- 62.5 pg/ml respectively. Although the same amount of fluid was ultrafiltrated in both groups, alpha-h-ANP decreased significantly in group I only, whereas in group II the decrease was not significant: 392.8 +/- 134.1 to 185.2 +/- 81.7 (P less than 0.001); 168.0 +/- 62.5 to 130.0 +/- 59 respectively. After achieving normovolaemia alpha-h-ANP concentrations in patients with a mitral valve insufficiency grade I was doubled compared to normovolaemic patients without mitral valve insufficiency, suggesting that alpha-h-ANP release will also occur from the left atrium. In the latter group alpha-h-ANP values were approximately doubled compared to healthy controls. The highly significant correlation between VCD before dialysis and changes in alpha-h-ANP during dialysis with fluid removal underlines the value of vena cava diameter in estimating volume status.
Nephrol Dial Transplant 1989
PMID:Plasma alpha-human atrial natriuretic peptide and volume status in chronic haemodialysis patients. 252 86

Based on the hypothesis that rapid corrections of pH, Na+ and osmolality give rise to disequilibrium (DES) during efficient haemodialysis (HD), a 14 compartment model has been designed for dynamic analysis of the induced fluid shifts and the resulting haemodynamic reactions. Simulated HD and ultrafiltration (UF) on the model were based on data from 11 steady state dialysis (RDT) patients (diffusion coefficients for urea, body fluid compartments, haemodynamic monitoring by Swan-Ganz catheters). The model reactions correlated remarkably with clinical findings and indicate how far a patient's haemodynamic compensation can prevent circulatory collapse and hypovolaemia, mainly through lowering the mean pressure in a major portion of the capillaries. Steady weight dialysis causes reduction of blood volume up to 65 per cent before circulatory collapse occurs.
Proc Eur Dial Transplant Assoc 1983
PMID:Computer modelling of haemodialysis/ultrafiltration explaining the pathogenesis of the disequilibrium syndrome. 687 51

Hypomagnesaemia with magnesuria are common findings in cyclosporin-(CsA)-treated patients and have been proposed as both a cause and a consequence of nephrotoxicity. To investigate the role of Mg depletion in the pathogenesis of acute CsA nephrotoxicity, rats kept on a low-salt diet were maintained on plain water (Mg(-)group) or water supplemented with 2% MgCl2 (Mg(+)group) and randomly assigned to treatment with CsA 15 mg/kg (CsA) or vehicle (VH) s.c. for 7 days. Water and food ingestion in VH animals was adjusted to the intake of CsA animals. CsAMg(-) group showed a significant plasma magnesium (PMg) reduction as compared to baseline (1.13 versus 1.53 mg/dl, P < 0.001) or VH values (versus 1.60 mg/dl, P < 0.001) and a significantly greater posttreatment fractional excretion of magnesium (FeMg) as compared to VH (9.4 versus 5.4%, P < 0.01). Magnesium supplementation increased PMg (2.11 versus 1.57 mg/dl P < 0.001) and FeMg (13.6 versus 6.2%, P < 0.001) but did not prevent a reduction in GFR with CsA treatment. Alanine aminopeptidase (AAP) excretion at 7 days was significantly greater than baseline (130 versus 44 IU/gCr, P < 0.05) or VH (36 IU/gCr, P < 0.05) values only in the CsAMg(-) rats. No differences were observed in intraerythrocyte Mg, blood pressure, and urinary excretion of N-acetyl-beta-D-glucosaminidase among groups. Renal histology was similar in CsA rats independent of magnesium supplementation: mild vacuolization and tubular collapse in proximal tubules.(ABSTRACT TRUNCATED AT 250 WORDS)
Nephrol Dial Transplant 1994
PMID:Effects of oral magnesium supplementation on acute experimental cyclosporin nephrotoxicity. 817 71

A correct estimation of volume status and so-called dry weight in dialysis patients remains a difficult clinical problem. Clinical status and chest X-ray are not sensitive enough, while invasively measured central venous pressures are not routinely available. Recently, the sonographic determination of the diameter and collapse of the inferior vena cava (IVC) has been proposed as a noninvasive method for estimating intravascular volume. We tried to evaluate the clinical relevance of this method in dialysis patients by comparing it with central venous pressures (CVP) and atrial natriuretic peptide (ANP). To establish a normal range and to control for confounding variables, we examined a large number of healthy controls. Furthermore, the influence of tricuspid insufficiency was examined echocardiographically. Measurements of the IVC diameters were well reproducible, with a coefficient of variation for interobserver error of 2.2%, and a coefficient of variation of 1.4% for intraobserver error. The collapse index was less well reproducible and therefore not used for further analysis. In 86 normal controls (age 18 to 76 years), IVC diameters showed a wide variation, and they were not correlated to age, height, weight, or body surface area. However, there was a significant correlation of IVCex to heart rate (r = 0.63, P < 0.001). Therefore, we calculated percentiles of the heart rate-IVCex relation in normals, and compared the results in patients to these. In 10 overhydrated haemodialysis patients, CVP was closely correlated to IVCex (r = 0.72, P < 0.001), but there was a wide interindividual variation of the slope of this relation. An IVCex above the 95th percentile of normal was a good predictor of an elevated CVP (i.e. > 12 cmH2O). In another 39 stable, chronic haemodialysis patients, there was a significant correlation of the intradialytic decrease of ANP and IVCex (r = 0.69, P < 0.001). However, this correlation existed only in patients without tricuspid insufficiency. In summary, sonography of the inferior vena cava is a valuable tool for estimating dry weight in dialysis patients, provided that some caveats are kept in mind: (i) there is a wide variation of IVC diameters in normals, and single measurements are not helpful in individual patients; (ii) there is a significant, inverse correlation between IVC diameters and heart rate, and the precision of intravascular volume assessment is enhanced by interpreting heart rate corrected diameters; (iii) the presence of tricuspid insufficiency leads to unreliable results, as it influences IVC diameters per se. Intravascular volume changes are reflected by IVC measurements, as shown by the correlation to other indices of intravascular volume, such as CVP and alpha-hANP. IVC sonography is noninvasive and easily available; serial measurements allow an estimation of changes of intravascular volume in patients without cardiac filling impairment. However, unlike with body impedance, interstitial volume is not reflected by IVC diameters.
Nephrol Dial Transplant 1996
PMID:Vena cava diameter measurement for estimation of dry weight in haemodialysis patients. 880 90

Focal and segmental glomerulosclerosis (FSGS) is one of the most common and non-specific patterns of glomerular injury encountered in human renal biopsies. The primary form can be considered when there is a nephrotic syndrome without other causes. The majority of authors agree that podocytes play a role in the development of segmental glomerulosclerosis. The lesion begins with cell hypertrophy, foot process effacement, cell body attenuation, pseudocyst formation, cytoplasmic overload with reabsorption droplets and finally detachment of the glomerular basement membrane (GBM). When the GBM is denuded, it comes into contact with the parietal epithelium and parietal epithelial cells will attach to the GBM, leading to a synechia and, finally, sclerosis. Along this zone, parietal epithelial cells rest on hyalin material. Occlusion and collapse of a group of capillaries is observed, with inclusion of foam cells and hyalin deposits. The origin of primary FSGS has not yet been elucidated. Genetic, racial and developmental factors, macrophages, viral factors and circulating factors are being explored and give encouraging results.
Nephrol Dial Transplant 1999
PMID:Morphological features of primary focal and segmental glomerulosclerosis. 1038 83

A specialist pediatric renal nursing service provides a link between hospital and home. Such support aims to reduce hospitalization and disruption to schooling and family routine. A 3-year prospective study monitored the progress and documented the nursing support to and contacts with 13 children (5 of whom were under 5 years of age) who commenced continuous cycling peritoneal dialysis (CCPD). Mean duration of CCPD was 14 months. Home and clinic contacts included telephone calls (65% of contacts), home, school, nursery, respite care, and community visits. Nine families received respite care from a home-care pediatric renal nurse, with children under 5 years receiving 68% of such visits. A total of 388 inpatient days were recorded. These included admission for catheter and dialysis training (125 days). hypertension (83 days), dialysis-related admissions (66 days), peritonitis (43 days), vomiting (31 days), and surgical procedures and infections (40 days). Nine peritonitis episodes occurred in 8 children (incidence 1 per 20 patient-months), and one death (cardiovascular collapse) occurred on CCPD. Seven children received a transplant, with the median waiting time for transplant being 7 months (range: 3-14 months). This study documents the spectrum of nursing support we have evolved to support children on CCPD and their families in the hope of reducing morbidity and hospitalization.
Adv Perit Dial 1998
PMID:Nursing contacts and outcomes in a pediatric CCPD program. 1064 41

Venous catheters differ from peripheral arteriovenous (AV) access devices in many important ways. This discussion focuses on their performance as a conduit for blood flow between the patient and the dialyzer and on how catheter function is both limited and enhanced relative to the more common peripheral accesses. Catheter flow is limited by the high resistance inherent in the extended length of venous catheters relative to dialysis needles, but the high rate of flow in central veins also diminishes the opportunity for access recirculation. Cardiopulmonary recirculation is absent in patients with catheter access unless the patient also has a peripheral access. In the latter case, the same detrimental effect on urea clearance is seen regardless of which access device is used. Flow-dependent recirculation through circuits other than the peripheral AV access reduces the efficiency of dialysis (regardless of the type of access, catheter, or peripheral AV device used) across both catheters and peripheral AV devices. The inside diameter of the catheter plays a sensitive role in determining catheter resistance to flow. Slight increases in diameter under the same pressure head are associated with large increases in flow. Negative pressure at the catheter inflow port generated by the blood pump is magnified relative to peripheral devices, predisposing to partial collapse of the pump tubing segment and erroneous blood flow readings by the pump motor speed indicator. Setting a limit on prepump negative pressure can minimize this error. Future applications of dialysis may require lower pump speeds, which would allow more liberal use of catheter access if their potential for infection and clotting can be reduced.
Semin Dial
PMID:Catheter performance. 1185 27


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