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K M Leunissen

Publications and source records attributed to K M Leunissen.

At least 19 recordsLinked to original sources
PubMed2001

[Acute renal replacement therapy in the intensive care unit].

On the intensive care department the most frequently used acute renal replacement techniques are intermittent haemodialysis and continuous haemofiltration. Although continuous techniques appear to have distinct advantages in the treatment of critically ill patients, no consistent differences in mortality have been found between continuous and intermittent treatment modalities. Due to uncertainty in this area, the use of unmodified cellulose membranes is probably best avoided. No good randomised studies are available with regard to the starting time of renal replacement techniques in critically ill patients. However, generally speaking a 'late' start should be avoided. With continuous techniques, the filtration volume should not be below 35 ml/kg/h. Although continuous (high-volume) filtration techniques may contribute to an improvement in the haemodynamics, the mechanisms behind this phenomenon remain unclear. At present, no randomised studies are available which have shown a beneficial effect of continuous techniques on the survival of critically ill patients without manifest renal insufficiency being demonstrated.

Critical Care↗
PubMed2001

A comparison between office and ambulatory blood pressure measurements in renal transplant patients with chronic transplant nephropathy.

Hypertension is an important risk factor for chronic transplant nephropathy. Therapy is usually based on casual office blood pressure (BP) measurements. However, it is not well known how casual BP predicts 24-hour BP in this population. The main focus of this study is to compare casual office BP with 24-hour ambulatory BP monitoring in renal transplant recipients with signs of chronic transplant nephropathy. Moreover, in this group, the day-night BP profile was assessed. In 36 renal transplant recipients with incipient or progressive proteinuria or an increase in serum creatinine level greater than 20%, 24-hour ambulatory BP was performed. Patients were defined as a nondipper if the mean BP decreased by less than 10% during the nighttime period. The correlation between single office and 24-hour ambulatory BPs was 0.61 for systolic BP and 0.55 for diastolic BP (P < 0.001). The mean difference between 24-hour ambulatory and single office BPs was -4.2 +/- 18.6 mm Hg (range, -44 to 36 mm Hg) for systolic BP and -1.1 +/- 10.7 mm Hg (range, -34 to 27 mm Hg) for diastolic BP; 94.5% of patients were classified as nondippers. There was a significant relation between the nightly decline in mean arterial pressure and calculated creatinine clearance (r = 0.34; P < 0.05). In conclusion, in renal transplant recipients with chronic transplant nephropathy, a large difference between office and ambulatory BPs is present, with both overestimation and underestimation of 24-hour BP by office BP measurements. Moreover, a severely disturbed day-night BP rhythm was observed. In transplant recipients with compromised graft function, office BP may not reflect 24-hour BP adequately, and ambulatory BP measurements should be considered.

Adult↗
PubMed2001

Role of bioimpedance spectroscopy in assessment of body water compartments in hemodialysis patients.

Bioimpedance spectroscopy (BIS) has been advocated as a tool to assess fluid status in hemodialysis (HD) patients. However, uncertainty remains about the reliability of BIS in patients with abnormalities in fluid status. Aims of the study are to assess the agreement between total-body water (TBW) and extracellular volume (ECW) measured by BIS and tracer dilution (deuterium oxide [D(2)O] and sodium bromide [NaBr]), the influence of the relative magnitude of water compartments (expressed as TBW(D(2)O) and ECW(NaBr):body weight) on the agreement between BIS and tracer dilution, and the ability of BIS to predict acute changes in fluid status. BIS and tracer dilution techniques were performed in 17 HD patients before a dialysis session. Moreover, the relation between BIS and gravimetric weight changes was assessed during both isolated ultrafiltration and HD. Correlation coefficients between TBW and ECW measured by BIS and tracer dilution were r = 0.71 and r = 0.71, respectively. Mean differences (tracer-BIS) were 6.9 L (limits of agreement, -1.5 to 21.6 L) for TBW and 2.3 L (limits of agreement, -1.7 to 9.7 L) for ECW. There was a significant relationship between the relative magnitude of TBW and ECW compartments and disagreement between BIS and tracer dilution (r = 0.65 and r = 0.77; P < 0.05). During both isolated ultrafiltration and HD, there was a significant relation between gravimetric changes and change in ECW(BIS) (r = 0.83 and r = 0.76; P < 0.05), but not with change in TBW(BIS). In conclusion, agreement between BIS and tracer dilution techniques in the assessment of TBW and ECW in HD patients is unsatisfactory. The discrepancy between BIS and dilution techniques is related to the relative magnitude of body water compartments. Nevertheless, BIS adequately predicted acute changes in ECW during isolated ultrafiltration and HD, in contrast to changes in TBW.

Adult↗
PubMed2001

Optimizing dialysis dose by increasing blood flow rate in patients with reduced vascular-access flow rate.

Dialysis efficacy indexed by Kt/V can generally be augmented by increasing the dialyzer blood flow rate. However, increasing the dialyzer blood flow rate may lead to vascular-access recirculation (AR) in patients with a compromised vascular-access flow rate. This can have an attenuating effect on dialysis efficacy. The aim of the present study is to investigate the effect of dialyzer blood flow rates of 200, 300, and 400 mL/min on AR and Kt/V in 8 patients with low (<600 mL/min) and 13 patients with normal (>600 mL/min) vascular-access flow rates. AR and vascular-access flow rate were determined using an ultrasound saline dilution technique, and session-delivered Kt/V was computed using an on-line dialysate urea monitor. AR was minor and only observed in 4 patients in the low vascular-access flow rate group (0.9% +/- 0.6%) at dialyzer blood flow rates of 200 mL/min (1 patient), 300 mL/min (2 patients), and 400 mL/min (3 patients) and 4 patients in the normal vascular-access flow rate group (1.2% +/- 1.1%) at dialyzer blood flow rates of 200 mL/min (3 patients) and 300 mL/min (1 patient). Kt/V increased with increasing dialyzer blood flow rates in both groups, and in individual cases, there was no decrease in Kt/V at greater dialyzer blood flow rates in either group. Also in those patients with minor AR, Kt/V increased at greater dialyzer blood flow rates, except in 1 patient in the low-flow group, in whom Kt/V remained unchanged at a change in dialyzer blood flow rate from 300 to 400 mL/min, whereas AR increased. From this study, it is concluded that even in patients with low access flow, increasing dialyzer blood flow rate in general leads to an increase in delivered Kt/V regardless of vascular access flow rate.

Aged↗
PubMed2000

Strategies for improving hemodynamic stability in cardiac-compromised dialysis patients.

In hemodialysis patients, structural changes at all levels of the cardiovascular system are common. The presence of these cardiovascular changes is a risk factor for the development of intradialytic hypotension. This explains the clinical observation that the incidence of symptomatic hypotension is high in elderly hemodialysis patients, who often have a history of long-standing hypertension and atherosclerosis, and in hemodialysis patients with cardiovascular disease. With an increasing number of cardiovascular compromised dialysis patients, special attention should be given to this group of patients. As the age of patients on hemodialysis increases steadily, it is a challenge to provide comfortable treatment in these patients by reducing the incidence of symptomatic hypotensive periods. This article describes the use of relatively new and simple clinical maneuvers to reduce the incidence of symptomatic hypotension.

Aged↗
PubMed2000

Effects of a venous cuff at the venous anastomosis of polytetrafluoroethylene grafts for hemodialysis vascular access.

INTRODUCTION AND METHODS: The most frequent complication of polytetrafluoroethylene (PTFE) arteriovenous grafts for hemodialysis is thrombotic occlusion due to stenosis caused by intimal hyperplasia. This complication is also known for peripheral bypass grafts. Because the use of a venous cuff at the distal anastomosis improves the patency of peripheral bypass grafts, we considered that it might also improve the patency of PTFE arteriovenous grafts. Therefore, a randomized multicenter trial was carried out to study the effect of a venous cuff at the venous anastomosis of PTFE arteriovenous grafts on the development of stenoses and the patency rates. RESULTS: Of the 120 included patients, 59 were randomized for a venous cuff. The incidence of thrombotic occlusion was lower in the cuff group (0.68 per patient-year) than in the no-cuff group (0. 88 per patient-year; P =.0007). However, the primary and secondary patency rates were comparable. The cuff group tended to have fewer stenoses at the venous and arterial anastomoses when examined with duplex scan. Graft failure was higher in patients with an initial anastomosing vein diameter smaller than 4 mm (7 of 18 [39%]) than in those with a vein diameter of 4 mm or larger (16 of 88 [18%]; P =. 052). Local edema, skin atrophy, and obesity yielded a higher risk on graft failure (23% vs 11%). CONCLUSION: A venous cuff at the venous anastomosis of PTFE arteriovenous grafts for hemodialysis reduced the incidence of thrombotic occlusions; stenosis at the venous anastomosis was reduced. However, this did not result in a better patency rate. Therefore, the venous cuff should not be used routinely. Initial vein diameter and local problems (edema, obesity, or skin atrophy) appear to be the most important risk factors for graft failure.

Arteriovenous Shunt, Surgical↗
PubMed1999

[Hypotensive periods during hemodialysis].

Hypotensive periods occur frequently during a haemodialysis session. The pathogenesis of intradialytic hypotension is multifactorial. The initiating factor is a decline in blood volume. Important contributory factors are inadequate vascular reactivity during haemodialysis and structural cardiovascular abnormalities. Compared with 'standard' haemodialysis, vascular reactivity is clearly increased during isolated ultrafiltration, haemodialysis with lowered fluid temperature (e.g. 36 degrees C), and haemofiltration. The single most important factor explaining these differences in vascular response is the thermal energy balance during the various treatment modalities. With a critical reduction of cardiac filling, the Bezold-Jarish reflex may occur, leading to paradoxical vasodilation and bradycardia.

Hemodynamics↗
PubMed1999

[Cardiovascular diseases in dialysis patients].

Cardiovascular morbidity and mortality are higher among dialysis patients than among the general population. The cardiovascular problems often exist before the start of dialysis. Their pathogenesis is multifactorial in dialysis patients also. The prevalence of left ventricular hypertrophy is strongly increased. Adequate therapy may lead to partial remission. Cardiac ischaemia is frequent among dialysis patients and may occur without severe coronary artery disease. The prognosis of myocardial infarction in dialysis patients is poorer than in the general population. There is no proven difference between the various dialysis techniques regarding cardiovascular morbidity and mortality, while kidney transplantation may have a beneficial effect. Early diagnosis and treatment aimed at risk factors for cardiovascular disease are indicated.

Cardiovascular Diseases↗