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At least 19 recordsLinked to original sources
PubMed1986

Experiments with continuous hemofiltration and hemofiltrate regeneration in the rat.

Experimental studies were made with continuous hemofiltration treatment for bilaterally nephrectomized rats and initial observations regarding the effects of such treatment on leukocyte and thrombocyte counts are reported. Hemofiltration of unanesthetized rats able to move freely within their cage could be continued for up to 30 h using a pump-driven ECC system. Blood parameters recorded during this treatment indicate that the detoxification was effective. In another series of experiments the water and electrolyte reabsorption capacity of the colon ascendens of healthy rats was tested by continuously supplying NaCl solution into the colon via a fistula. A large proportion, if not all, of the hemofiltrate can be discharged into the colon without diarrhoea. A final series of experiments showed that the three-stage operation (implantation of permanent catheters, connection of a permanent intestinal fistula and bilateral nephrectomy) is possible with the rat.

Animals↗
PubMed1991

Continuous venovenous hemofiltration: an alternative to continuous arteriovenous hemofiltration and hemodiafiltration in acute renal failure.

Continuous venovenous hemofiltration (CVVH) has been used as an alternative to continuous arteriovenous hemofiltration (CAVH) and hemodiafiltration (CAVHD) in the management of critically ill patients with acute renal failure. This report describes our experience with the first 25 patients treated with CVVH at our institution. Vascular access was obtained through a single dual-lumen venous catheter. A blood pump was used to provide ultrafiltration pressure. An ultrafiltrate pump was incorporated to ensure predictable ultrafiltrate production rates. Safety features in the extracorporeal circuit included a venous drip chamber with bubble detector and an in-line pressure monitor. CVVH was initiated by a nephrologist and dialysis nurse and was maintained by the intensive care unit (ICU) nursing staff. Fifteen females and 10 males received CVVH therapy for a total of 193.5 days (average, 7.7 +/- 10.3 days; range, 0.5 to 48 days). Four of the 25 patients (16%) survived and were discharged from the hospital. Four additional patients (16%) survived the acute phase of their illness, but died from complications of their primary disease before discharge from the hospital. The mean weight change during CVVH was -7.9 +/- 7.0 kg (range, -26.5 to +2.9 kg). Metabolic waste products and electrolytes were adequately controlled by CVVH in all but one hypercatabolic patient. The mean heparin dose required was 6.5 +/- 4.2 U/kg/h and was adjusted to prevent filter clotting rather than to achieve a predetermined activated partial thromboplastin time (PTT). The median PTT was 35.8 seconds (range, 22.0 to 100; control, 19.5 to 29.5 seconds). Four episodes of volume-responsive hypotension occurred during the 193.5 treatment days. Only one patient experienced a hemorrhagic complication during CVVH. No patient experienced a complication related to vascular access. Twelve of 111 total hemofilters were changed because of clot formation. CVVH was well tolerated by patients and managed efficiently by the ICU nursing staff.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗
PubMed1990

Improvement of continuous arteriovenous hemofiltration (CAVH) and hemofiltration (HF) efficiency by adding hemoperfusion (HP).

Aiming to improve the efficiency of the blood purification convective methods either with spontaneous (CAVH) or with pump-assisted (HF) extracorporeal circulation we inserted after the hemofilter a cartridge containing 70 g of collodion-coated activated charcoal (CAC) microencapsulated, obtaining so hemofiltration and hemoperfusion in series (HF+HP). The obtained results show that in both methods HP addition gives a negligible increase of urea clearance and a practically null increase of phosphate clearance, whereas creatinine and uric acid clearances increase is remarkable especially, in percentage, with low blood flows (CAVH). In the HF+HP system we have also been studying B2-microglobulin (B2-M) clearance aiming at examining the possibility of increasing the removal of substances with higher molecular weight. We have been finding HP addition increases further on B2-M clearance already high in HF. Therefore we think HP addition to convective methods is an interesting step in the attempt to carry out highly efficient blood purification methods.

Creatinine↗
PubMed1986

A continuous hemofiltration system using sorbents for hemofiltrate regeneration.

Plasma ultrafiltrate obtained by glomerular filtration undergoes tubular modification which leads to the elimination of toxic substances, excess water and electrolytes, and consequently maintains homeostasis. Using normal urine and the substances it contains as a reference, we have developed a wearable device capable of replacing both the renal excretion function and maintaining fluid and electrolyte equilibrium in uremics within acceptable biological limits. Our device includes a hemofilter allowing continuous plasma ultrafiltration and sorbents obtained from a Redy sorbent cartridge to treat 85% of the ultrafiltrate, whereas 15% of this UF is rejected untreated. After calculating the quantity of ultrafiltrate (about 13 l) containing an amount of waste products of metabolism equivalent to 24-h urine elimination, we determined in vitro the amount of sorbent required to eliminate these waste products from the ultrafiltrate (e.g., 20 g of urea/day) and we have evaluated the quantities of other substances which must be replaced using a tailored diet. This extra-corporeal detoxification process was used in a uremic patient who had been on traditional hemodialysis for the past two years. The continuous treatment permitted maintenance of fluid and electrolyte equilibrium at the desired level and allowed rapid improvement of patient clinical status: elimination uf nausea, vomiting, diarrhea and edema, which had previously reappeared during the interdialytic periods, as well as a rapid decrease in heart size as ascites disappeared. In addition, the patient regained sexual drive and the ability to have an erection. In conclusion, traditional hemodialysis and hemofiltration techniques allow intermittent elimination of products retained by the body and reestablish nearly normal fluid and electrolyte balance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adsorption↗
PubMed1985

[Positive modification of hemodynamics in post cardiac surgery patients by hemofiltration. Improved method for the demonstration of myocardial depressant factor (MDF) in hemofiltrate].

The method of haemofiltration was used in 29 postoperative cardio-surgical patients with low blood pressure, high left ventricular filling pressure and low total peripheral resistance, which did not respond to the use of the intraaortic balloon pump or pharmaco-therapy. In severe low-output syndrome hemodynamic parameters are: reduced mean arterial pressure, increased left ventricular filling pressure, increased mean arterial pulmonary pressure as well as significantly reduced total peripheral resistance [4-6, 28]. Inspite of pharmaco-therapy, cardiac performance regarding peripheral perfusion is insufficient; this leads to a vicious cycle of irreversible O2-debt and severe cellular damage. After haemofiltration there was a significant improvement in the haemodynamic parameters, which in our opinion was due to the elimination of toxic peptides such as Myocardial Depressant Factor (MDF). In 27 of a total of 29 patients, haemodynamic parameters returned to normal after treatment. 19 patients were discharged, eight patients died after a number of days or weeks from causes not related to the original cardiogenic shock (cerebral embolism, reinfarction, myocardiopathy and pneumonia).

Adult↗
PubMed1989

Four years' experience of long-term hemofiltration in a Swedish center.

Thirty patients with end-stage renal disease were switched from maintenance hemodialysis to postdilution hemofiltration and observed for long-term effects. The study comprised totally 496 months of hemofiltration. Uremic and biochemical control was similar in the hemofiltration and in the hemodialysis period. Of the small molecules, only serum creatinine showed slight increase after 3 months. No other significant changes in creatinine, serum urea or potassium levels were associated with long-term hemofiltration. During each hemofiltration session there was significant decrease of serum parathyroid hormone (PTH) and serum beta 2-microglobulin, but over the first 8 months of hemofiltration the beta 2-microglobulin values did not fall, and significant PTH reduction was found only after 12 months. Although uremic control was similar with both methods, there were fewer complications of hemofiltration, which was preferred by the patients. Because it is currently more expensive, however, hemofiltration should be reserved for patients with dialysis related problems, that are not helped by other changes in the dialysis technique, such as sequential ultrafiltration changes in the dialysis membranes and in the dialysis buffer from acetate to bicarbonate.

Female↗
PubMedDate not supplied

Removal of sulfonamides by hemofiltration.

Hemofiltration is a relatively new technique for removing toxic substances from the body. Unlike hemodialysis or hemoperfusion, the driving force behind hemofiltration is ultrafiltration. There have been several studies examining the clearance of drugs by hemofiltration but to date no study has investigated in a systematic way the effects of protein binding, perfusate flow, transmembrane pressure, and the duration of treatment on drug clearance by hemofiltration. The influence of these factors on the hemofiltration clearance of three sulfonamides with differing degrees of protein binding was investigated. It was found that hemofiltration drug clearance decreased with the duration of hemofiltration and protein binding but increased with perfusate flow and transmembrane pressure.

Animals↗
PubMed1992

Continuous arteriovenous hemofiltration after cardiac operations in infants and children.

Acute renal insufficiency after cardiopulmonary bypass can lead to a significant morbidity from fluid overload and electrolyte disturbance, impede pulmonary gas exchange, and postpone weaning from mechanical ventilation. The limitations placed on free water intake result in severe restriction of nutrition while diuretic therapy causes electrolyte imbalance. Artificial renal support either in the form of peritoneal dialysis or hemodialysis may be complicated by sepsis and hemodynamic instability. We reviewed our experience with the use of continuous arteriovenous hemofiltration, an extracorporeal technique for removal of solutes, toxins, and water in critically ill patients with cardiac failure complicated by acute renal insufficiency and hemodynamic instability after cardiopulmonary bypass. Ten infants and children with renal insufficiency caused by low cardiac output had continuous arteriovenous hemofiltration instituted for indications including sepsis, volume overload, oliguria for more than 24 hours nonresponsive to diuretic therapy, and the need for hyperalimentation. All were supported by mechanical ventilation and receiving high-dose inotropic support. Arterial and venous vascular access was successfully obtained by cannulation of the femoral artery and vein in nine patients. Anticoagulation of the circuit was achieved with heparin infusion (6 to 20 micrograms/kg/hr) and monitored by measurement of activated clotting time. The continuous arteriovenous hemofiltration circuit was replaced if there was clot formation, or at 3 days after placement. Dialysis solution (Dianeal) 1.5% or 0.5% was infused as prefilter dilution. With the use of continuous arteriovenous hemofiltration, 20 to 100 m/hr of ultrafiltrate was removed, which allowed correction of hypervolemia, and caloric intake increased from 13.5 kcal/kg/day to 79.5 kcal/kg/day. Continuous arteriovenous hemofiltration was maintained between 5 hours and 8 days and was well tolerated in all patients. Serum urea and creatinine levels declined during continuous arteriovenous hemofiltration. We conclude that continuous arteriovenous hemofiltration is a safe and effective method for fluid and electrolyte homeostasis and that it thus allows hyperalimentation in infants and children after cardiac operations.

Acute Kidney Injury↗
PubMed1992

Acute continuous hemofiltration with dialysis: effect on insulin concentrations and glycemic control in critically ill patients.

OBJECTIVES: To quantitate insulin losses and glucose absorption during acute continuous hemofiltration with dialysis and to assess the clinical importance of these changes. DESIGN: Prospective collection of serum and ultradiafiltrate fluid in patients receiving acute continuous hemofiltration with dialysis. Measurements of serum and ultradiafiltrate insulin and glucose concentrations. Calculations of insulin excretion and glucose absorption. Correlation of findings with patient outcome. SETTING: University medical center. PATIENTS: Sixteen ICU patients with acute renal failure. MEASUREMENTS AND MAIN RESULTS: The mean serum glucose concentration before acute continuous hemofiltration with dialysis was 178 mg/dL (9.9 mmol/L) (95% confidence interval 112 to 244 mg/dL [6.2 to 13.6 mmol/L]), increasing to 257 mg/dL (14.3 mmol/L) (95% confidence interval 167 to 347 mg/dL [9.3 to 19.3 mmol/L]) after 4 hrs of acute continuous hemofiltration with dialysis, and stabilizing at 207 mg/dL (11.5 mmol/L) (95% confidence interval 160 to 254 mg/dL [8.9 to 14.1 mmol/L]) at 24 hrs. Mean plasma insulin concentration before acute continuous hemofiltration with dialysis was 34.4 mU/L (95% confidence interval 8.6 to 60.2 mU/L), increasing to 54.4 mU/L at 4 hrs (95% confidence interval 25 to 83.8 mU/L; NS). There was no significant decrease in mean insulin concentration across the filter (51.8 mU/L before filtration vs. 51.9 mU/L after filtration). Insulin was detected in the ultradiafiltrate but its overall mean clearance rate was only 6.2 mL/min, with mean daily losses of 689 mU/day (95% confidence interval 325 to 1053 mU/day). During acute continuous hemofiltration with dialysis, glucose absorption through the filter averaged 134 g/day (95% confidence interval 96.2 to 171.8 g/day). Plasma insulin concentrations were significantly (p < .05) lower in survivors than nonsurvivors (51.7 vs. 123.6 mU/L). CONCLUSIONS: Significant glucose absorption occurs during acute continuous hemofiltration with dialysis and is coupled with minor insulin losses (< 1 U/day) through the filter. These events do not appear to have major clinical impact. A low plasma insulin concentration is associated with diminished mortality rates in this group of patients.

Acute Kidney Injury↗
PubMed1989

Blood conservation in cardiac operations. Cell separation versus hemofiltration.

The effects of hemoconcentration performed during and after extracorporeal circulation by either centrifugation (cell separation group, n = 20) or hemofiltration (n = 20) were investigated in 40 patients undergoing elective aorta-coronary bypass grafting. Interest was focused on the quality of the blood concentrated from the blood remaining in the extracorporeal circuit and on the reaction of the patients after retransfusion of the concentrated products. Hemofiltration was easy to perform and produced whole blood quicker than the cell separation technique. Coagulation studies revealed no significant differences in heparin concentration, levels of fibrinogen and antithrombin III, or platelet counts. Various coagulation parameters tended to normalize completely and more quickly after hemofiltration than after centrifugation. None of the patients had severe bleeding postoperatively. Free hemoglobin levels were not affected by hemofiltration; elastase concentration was higher only immediately after retransfusion of the concentrated blood, with no effect on organ function. We conclude that both methods were effective means of hemoconcentration during extracorporeal circulation and in salvaging the diluted pump blood after extracorporeal circulation. Loss of plasma fraction is an important disadvantage in the centrifugation technique, which can be avoided by hemofiltration; derangement in colloid osmotic pressure and coagulation parameters was less pronounced after hemofiltration. Costs were lower, as well. Therefore, when a high volume of cardioplegic solution and two-stage cannulation are used, hemofiltration seems to be the method of choice for blood conservation during cardiac operations.

Aged↗
PubMed1986

Disposition of vancomycin during hemofiltration.

The disposition of vancomycin was assessed in five patients receiving hemofiltration after intravenous dosing with an 18 mg/kg dose after a hemofiltration procedure. The serum concentration-time profile was characterized before, during, and after the next hemofiltration procedure. The t 1/2 of vancomycin was 136.0 +/- 27.2 hours (mean +/- SD) before hemofiltration and 4.1 +/- 1.2 during hemofiltration. Approximately 400 mg of vancomycin was recovered in the filtrate and the hemofiltration clearance was 152.6 +/- 21.5 ml/min. A significant relationship was observed between vancomycin clearance and ultrafiltration flow rate (r = 0.9914). A marked rebound in vancomycin serum concentration (52.4% +/- 15.6%) was observed in all patients. Hemofiltration has a significant effect on the disposition of vancomycin. Because of the marked interpatient variability in elimination t 1/2 and the degree and time course of the rebound, an individualized approach to vancomycin therapy in this patient population is recommended.

Aged↗
PubMed1992

Hemofiltration as treatment for patients with refractory heart failure.

Hemofiltration was performed in 15 patients with refractory congestive heart failure. All of these patients had oliguria, although intensive treatment with diuretics, digitalis, vasodilators, and catecholamines was prescribed. Hemofiltration was performed under hemodynamic monitoring in 14 patients. The water removal by hemofiltration decreased pulmonary arterial pressure, pulmonary capillary wedge pressure and right atrial pressure. Despite these hemodynamic improvements, nine patients (60%) died within one month after the start of hemofiltration; the causes were fatal arrhythmia in three, renal failure in two, sepsis in one and irreversible cardiogenic shock in three. Oliguria for over 15 h or a serum creatinine concentration of more than 4.0 mg/dl at the start of hemofiltration related to poor prognosis. In view of these results, hemofiltration for refractory heart failure should be started earlier and performed carefully in order to avoid arrhythmia, cardiogenic shock, and other complications.

Adult↗
PubMed1989

Elimination of vancomycin during hemofiltration.

The study was designed to establish guidelines for vancomycin treatment of patients with acute renal failure undergoing hemofiltration. During 27 hemofiltration treatments in four anuric patients requiring daily consecutive hemofiltration therapy, plasma levels and elimination rates of vancomycin were measured. Regression analysis of the initial vancomycin concentration versus the total amount of vancomycin eliminated showed a clear linear relationship (r = 0.91), thus permitting prediction of the total elimination via hemofiltration by measurement of the initial plasma concentration. Applying these calculations the dosage in patients undergoing hemofiltration can be determined by monitoring the initial plasma concentration. The findings also indicate that hemofiltration is an effective method for treatment of vancomycin intoxication.

Acute Kidney Injury↗
PubMed1987

Hemofilter reuse in maintenance hemofiltration.

The practice of multiple use of hemofilter was examined on 16 patients in our dialysis center. The hemofilters were cleaned by reverse ultrafiltration using positive pressure in the blood and filtrate compartment of the hemofilter. Ten hemofilters used for continuous arteriovenous hemofiltration, 6 hemofilters used for pump-assisted acute hemofiltration and seventy hemofilters used for chronic maintenance hemofiltration were studied for the clearances of urea nitrogen and creatinine and sieving coefficients of albumin and electrolytes. Hemofilters were successfully reused in pump-assisted acute hemofiltration and chronic hemofiltration. In continuous arteriovenous hemofiltration, hemofilters could not be reused mainly because of clotting of fibers. The practice is safe, efficient and highly cost-saving.

Equipment Contamination↗