Continuous Arteriovenous Hemofiltration Research Articles

Continuous arteriovenous hemofiltration in experimental iron intoxication.

This study evaluated continuous arteriovenous hemofiltration (CAVH) as a method for removing the iron-deferoxamine complex in experimental iron intoxication. Five anesthetized dogs were instrumented for hemodynamic monitoring and then given 600 mg/kg of elemental iron as ferrous sulfate. After a 3-h absorption period, CAVH was begun from the femoral artery to femoral vein. Deferoxamine was infused into the arterial lines of the CAVH cartridge at increasing doses. We found a dose-dependent increase in the ultrafiltrate excretion of iron. However, most of the deferoxamine was excreted unbound. The efficiency of complex formation was greater at lower BP and ultrafiltrate formation rate, suggesting that inadequate mixing of deferoxamine with blood may occur when arterial administration is used. Iron excretion in the urine over the same time period was not significantly greater than that removed by CAVH. We conclude that CAVH can remove iron using deferoxamine as a chelating agent.

Prognosis of Critically-ill Patients with Acute Renal Failure: APACHE II Score and Other Predictive Factors

The survival from acute renal failure requiring renal replacement therapy was studied in 90 critically-ill patients admitted to an intensive care unit. Mean age (+/- SD) was 51 +/- 14.6 (range 17 to 81) years. Mechanical ventilation was required in 88 patients and 71 patients received total parenteral nutrition. Thirty-three per cent of patients left the intensive care unit alive and 24 per cent survived to leave hospital. Final survival was 20 per cent in medical patients (n = 49), 29 per cent in surgical patients (n = 38) and 100 per cent in obstetric patients (n = 3). Hypotension, requirement for inotropic support, oliguria and sepsis were all associated with a poorer prognosis. The mode of renal replacement therapy did not affect survival, but additional haemodialysis was required in 33 of 65 patients treated by continuous arteriovenous haemofiltration but none of 22 treated with continuous arteriovenous haemodialysis (p less than 0.001). APACHE II score was calculated for 87 patients. Mean APACHE II score was 26.1 +/- 6.9 (range 14 to 44). APACHE II score on admission predicted the likelihood of survival well. No patients with a score of more than 40 survived, compared to 40 per cent of those with scores of 10 to 19. Pre-existing organ insufficiency or immunosuppression meriting a CHE score of 5 was associated with a very poor survival (1 of 30 patients). APACHE II score is a reliable indicator of severity of illness and likelihood of survival in critically-ill patients with acute renal failure. The widespread adoption of APACHE II scoring for patients with acute renal failure requiring intensive care would facilitate medical audit and comparison of studies from various centres.

Use of extracorporeal supportive techniques as additional treatment for septic-induced multiple organ failure patients

We compared retrospectively four similar groups of patients with multiple organ failure (MOF) due to sepsis. All of them were treated initially with conventional therapy, aprotinin as protease inhibitor and vitamin C with allopurinol as possible scavengers of oxygen-free radicals, were also added. After 24 h of no clinical progress, continuous arteriovenous hemofiltration (CAVH), CAVH/dialysis (CAVH/D), and sequential plasmafilter-dialysis with slow continuous hemofiltration (CAVHP/D) were respectively added to groups 2 (n = 14), 3 (n = 6), and 4 (n = 11). Mortality was 87% for group 1, 71% for group 2, 50% for group 3, and 36% for group 4. In the latter we were able to remove possible MOF-inducing mediators from the bloodstream, to give fluids without restriction (even in oliguric patients), and to improve removal of metabolic waste products. It is possible that these extracorporeal supports, associated with conventional therapy, and pharmacologic drugs such as protease inhibitors and possible scavengers of oxygen-free radicals, helped to reduce the mortality rate. We conclude that, although the number of study patients was too small to reach firm conclusions, the good results observed with CAVHP/D suggest clinical trials to assess the efficacy of this technique.

Changes of the serum amikacin (AMK) level in patients with serious acute renal failure treated by continuous arteriovenous hemofiltration (CAVH).

This study clarified changes in the serum amikacin (AMK) levels in the blood of 5 patients (4 men and 1 woman; average age 59.2 +/- 5.9 years) with serious acute renal failure treated by continuous arteriovenous hemofiltration (CAVH). The following principal results were obtained. (A) The average remaining rate of AMK in the blood after 6 h was 60.8 +/- 5.3% and 50.4 +/- 5.3% after 12 h. The average half-life period (t1/2 beta) of AMK in the blood during CAVH was 18.3 +/- 3.4 h. (B) The remaining rate of AMK in the blood after 12 h correlated significantly with the blood urea nitrogen (BUN) level (r = 0.71, p less than 0.05) and with the volume of urine excreted per day (r = -0.71, p less than 0.05). (C) The average lowest AMK concentration after 24 h for a continuous 17-day period was 3.3 micrograms/ml. These results suggest that the administration of 100 mg of AMK once a day is useful and safe for patients with serious acute renal failure treated by CAVH and that it will not accumulate in the body.

Continuous arteriovenous haemofiltration in children.

Continuous arteriovenous haemofiltration (CAVH) was used in 7 critically ill children: a premature neonate with hypervolaemia secondary to hydrops foetalis and six children aged 9 days to 7 years with acute oliguric renal failure. Biospal 0.5 m2, Renaflo 0.25 m2, Gambro 0.15 m2 and Amicon 0.015 m2 filters were used according to the weights and ages of the patients. Adequate removal of water and solutes was obtained in 6 patients. One of the patients with the smallest filter needed a change to a filter with a larger surface area to improve water and solute removal. Haemofiltration was maintained for between 17 hours and 31 days and was well tolerated. CAVH was discontinued because of recovery of renal function in three patients, improvement of the hypervolaemic state in one, death in three, and transfer to continuous ambulatory peritoneal dialysis because of chronic renal failure in one patient. CAVH is a useful technique for the treatment of acute renal failure and hypervolaemia in critically ill children.

Continuous arteriovenous hemofiltration in premature infants

Five critically ill premature infants with acute renal failure (ARF) and hypervolemia were treated by continuous arteriovenous hemofiltration (CAVH). Prostacyclin was used to prevent hemofilter clotting. Mean treatment duration was 53.6 +/- 14 h. Mean blood flow rates of 1.6 +/- 0.22 ml/min and filtration fractions of 17.2 +/- 3.7% produced mean ultrafiltration rates of 8.3 +/- 3.1 ml/kg.h. Fluid overload was easily corrected by means of CAVH. The mean prehemofiltration serum creatinine and urea levels were 2.3 +/- 0.4 and 77 +/- 29.7 mg/dl; the mean posthemofiltration levels were 2.38 +/- 0.43 and 92 +/- 34.4 mg/dl, respectively. Hemofilter clotting occurred every 14 h. Urinary output was restored in three infants. Three of the five infants died, but none of the deaths was related to ARF or CAVH. CAVH is a safe and simple method to control fluid and metabolic imbalances in critically ill premature infants.

Removal of Cephalosporins by Continuous Arteriovenous Ultrafiltration (CAVU) and Hemofiltration (CAVH)

Cephalosporins are used with increasing frequency for sepsis treatment in patients receiving CAVU and CAVH. The different cephalosporins share the same basic molecular structure, yet they exhibit varied extent of plasma protein binding. Different amounts of the antibiotics may be removed by the ultrafiltration procedure because of these variations of physicochemical properties. We evaluated the sieving of eight new cephalosporins across the hemofilter membrane using an in vitro model. Bovine blood was perfused through polysulfone membranes at blood and ultrafiltrate flow rates of 100 and 20 ml/min respectively. Arterial plasma, venous plasma and ultrafiltrate drug concentrations were used to determine sieving coefficients. The sieving coefficients correlated well with the ultrafiltrate-arterial plasma drug concentration ratio (r = 0.679-0.972) but poorly with the extent of protein binding. Factors other than protein binding may therefore affect the drug sieving. Based on the findings, it was predicted that 0.2-21.9% of the daily cephalosporin dose may be removed by the CAVU and CAVH treatment. The need to alter drug dosages depends on the techniques of the ultrafiltration and hemofiltration procedure, the kinetics of the cephalosporins in patients, the sensitivity of the pathogen and the nature of the infection.

QA in Continuous Arteriovenous Hemofiltration

As new treatment modalities pervade the clinical setting, quality monitoring tools must be developed to assess compliance with standards. Continuous arteriovenous hemofiltration, an alternative treatment of patients in renal failure, is becoming common in intensive care units. Because of the increased emphasis on specialization and in order to fulfill their responsibility to provide quality care, critical care practitioners can conduct concurrent evaluations for patients receiving this form of therapy.

Single-Dose Kinetics of Imipenem/Cilastatin During Continuous Arteriovenous Haemofiltration in Intensive Care Patients

The single i.v. dose kinetics of a fixed combination of imipenem/cilastatin were investigated in ten critically ill patients treated by continuous arteriovenous haemofiltration (CAVH). Eight patients suffered from acute renal failure and two had normal renal function. Both drugs were measured in plasma and ultrafiltrate by high-performance liquid chromatography. While the pharmacokinetics of both drugs are almost identical in patients with normal renal function, we found the following dissociation of pharmacokinetic parameters in our patients with renal failure: for imipenem the total clearance and elimination half-life was 104 +/- 12 ml/min and 2.2 +/- 0.1 h, respectively, and for cilastatin 29 +/- 10 ml/min and 13.8 +/- 4.5 h. The pharmacokinetics of imipenem and cilastatin differ from each other in renal failure because imipenem, unlike cilastatin, undergoes marked elimination by non-renal pathways. Our results did not differ from previously reported data in healthy volunteers and patients with impaired renal function. Elimination of imipenem by CAVH was low (7% of the dose). As a consequence of the unsatisfactory non-renal clearance of cilastatin, however, the fraction of the dose removed by CAVH was significantly greater (approximately 30%) than that of imipenem. This did not, however, correct the dissociation of the pharmacokinetic profiles of the two drugs. In conclusion, the dose of imipenem/cilastatin in critically ill patients with renal failure treated by CAVH should be modified according to renal function but elimination by CAVH does not need to be considered.

Comparison of Five Modes of Dialysis in Neurosurgical Patients with Renal Failure

In neurosurgical patients with renal failure, dialysis entails specific problems, chief of which is increased intracranial pressure and progressive brain edema as a result of rapid lowering of the serum osmolality. Another major problem is a tendency to hemorrhage, in response to either systemic heparinization or insufficient dialysis. The authors describe the results obtained with hemodialysis (HD), continuous arteriovenous hemofiltration (CAVH), continuous ambulatory peritoneal dialysis (CAPD), continuous peritoneal dialysis (CPD), and intermittent peritoneal dialysis (IPD). Nine patients were treated with HD, one with CAVH, five with CAPD or CPD, and two with IPD. Three of the six patients treated with continuous dialysis (CAVH, CAPD, and CPD) died, whereas intermittent dialysis (HD and IPD) carried an 82% mortality rate (nine of 11 patients). The causes of death were progressive brain edema in three cases, intracranial hemorrhage in three, gastrointestinal bleeding in three, overhydration due to insufficient dialysis in one, septicemia in one, and rupture of a cerebral aneurysm in one. Continuous dialysis appeared to be superior to intermittent dialysis in these neurosurgical patients in that it produced less brain edema and was less often associated with hemorrhage due to insufficient dialysis. In HD and CAVH, systemic heparinization was also thought to account for the high incidence of hemorrhage. However, CAVH with short half-life anticoagulants may be useful in patients who have abdominal complications and are therefore not suitable candidates for peritoneal dialysis.

Continuous Arteriovenous Haemofiltration in the Newlyborn with Acute Renal Failure and Congenital Heart Disease

Newlyborn infants with congenital heart disease who develop acute renal failure are particularly difficult to treat. There are often complex associated medical problems and the mortality is high. Continuous arteriovenous haemofiltration (CAVH) provides a slow and gentle removal of fluid, together with the possibility of correcting metabolic abnormalities. We used CAVH in six newlyborn infants all with severe congenital heart disease, who developed acute renal failure early in life. In four patients it was necessary to insert a blood pump into the circuit to maintain adequate blood flow. CAVH alone, with or without a blood pump, was unable to reduce the plasma urea and creatinine, and in three of the infants, dialysis across the filter was required. CAVH was effective in controlling fluid balance. Although mortality remains high we feel CAVH has an important role in selected patients.

Outcome of continuous arteriovenous haemofiltration (CAVH) in one centre.

Continuous arteriovenous haemofiltration (CAVH) has been adopted as the treatment of choice for acute renal failure (ARF) in critically ill patients in the intensive care units of Uppsala University Hospital since 1982. To know the outcome of CAVH during the last one and a half year this retrospective study was done on those patients seen in July 1987-December 1988. Forty patients aged 2 months-84 years (mean 57 years) were included. Treatment duration was 1-31 days (mean 10 days, patients with treatment duration less than 24 h were excluded). The majority of ARF causes were due to major surgery because there are two big cardiothoracic and vascular surgical centres with a high turnover in this hospital. In this study CAVH was found useful in the management of ARF in critically ill patients within the limits of its capacity of urea clearance. There is a notable improvement in the number of survivors in this study (55%) when this is compared to a previous study (45%) in a similar group of patients and in the same centre.

Continuous arteriovenous renal replacement systems for critically ill children

Five different arteriovenous renal replacement systems were used to treat 23 critically ill oliguric or anuric children. Slow continuous ultrafiltration (SCU) was carried out for 8 patient days, continuous arteriovenous haemofiltration (CAVH) for 40, suction-supported CAVH for 56, continuous or intermittent arteriovenous haemodiafiltration (AVHDF) for 3, and continuous arteriovenous haemodialysis (CAVHD) for 24 days. SCU allowed excellent control of fluid overload in 4 patients within 47 +/- 17 h. Urea clearances ranged from 5.6 +/- 2.1 ml/min per m2 (spontaneous CAVH) to 15.3 +/- 3.7 ml/min per m2 (CAVHD) and enabled good control of azotaemia. Ultrafiltration rates of the different filters ranged from 1.6 +/- 0.3 to 11.5 +/- 2.4 ml/min per m2. The only serious complication was a femoral artery thrombosis in a 1.5-year-old boy. Minor side-effects were local bleeding at the entrance site of the arterial catheter and transient hypotension during suction-supported CAVH. Of 23 patients, 8 died because of progressive multiple organ system failure, a mortality of 35%.

Multivariate analysis of aminoglycoside levels in hemodialysis patients.

Multivariate discriminant analysis was performed on data for 50 consecutive hemodialysis patients who had received aminoglycoside treatment because of severe bacterial infections. The 10 of the 60 clinical parameters considered to be most important were survival of patients (28/50 patients), success of treatment (27/50 patients), acute or chronic renal failure (15 vs. 35), age (54 +/- 17 years), creatinine level (675 +/- 298 mumol/l), artificial ventilation (21/50 patients), need for catecholamines (19/50 patients), continuous arteriovenous hemofiltration (9/50 patients), duration of therapy (12 +/- 8 days) as well as aminoglycoside peak (7.5 +/- 2.7 mg/l) and trough levels (3.6 +/- 1.3 mg/l). The 4 of the 10 parameters investigated by multivariate analysis significantly contributing to survival of patients were clinical success of aminoglycoside treatment (p = 0.0001), no need for catecholamines (p = 0.0001), duration of dosage (p = 0.003) and aminoglycoside peak levels (p = 0.009).

Continuous arterio-venous hemofiltration: optimization of technical procedures and new directions.

In 1977 Peter Kramer treated the first patient affected by acute renal failure (ARF) with a new treatment modality called Continuous Arterio-Venous Hemofiltration (CAVH) (1).KeywordsAcute Renal FailureBlood PumpExtracorporeal CircuitHigh Blood FlowUltrafiltration RateThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Drug therapy during continuous arteriovenous hemofiltration.

Since the first description of continuous arteriovenous hemofiltration as a method of emergency fluid removal (Kramer et al. 1977), this measure has gained wide acceptance predominantly as a supportive treatment of acute renal failure in critically ill patients. It has been shown that the machinefree hemofiltration allows liberal parenteral nutrition without the risk of fluid overload. In addition it has some capacity to remove uremic toxins. The method can be applied without sophisticated apparative equipment and without trained dialysis personal being familiar with the problems of extracorporal circulation.

Innovative extracorporeal membrane systems

This paper is a review of innovative extracorporeal membrane systems (ECMS) for the separation of free- and protein-bound solutes below the size of albumin as applied to the treatment of end stage renal disease (ESRD), liver failure and cancer. The most well-known ECMS is hemodialysis (HD) for the treatment of ESRD patients. Attempts were made over the last 30 years to improve the HD system with several objectives, namely: (i) to increase clearances of small and middle molecules; (ii) to eliminate problems associated with removal of excess body-fluid; (iii) to decrease treatment time; (iv) to eliminate blood pump; and (v) to make the system simple, inexpensive, portable or wearable and operating continuously. These attempts lead to hemofiltration (HF) or ultrafiltration with pre- or post-hemodilution, hemoperfusion (HP), sorbent regeneration systems (SRS), and various combinations of HD, HF, HP and SRS, high-flux largesurface ultra-short HD, and continuous arteriovenous HF. These developments are hindered by a lack of understanding on“adequate dialysis”, confusion caused by “acetate-HD”, and failure to find a high-capacity urea-adsorbent. Developments in ECMS with enzyme reactors, bioartificial systems containing cultured cells and monoclonal antibodies, as adjunct therapies for liver failure and cancer are slow. All the above systems deal with modulation of plasma or hemofiltrate, but ECMS for the selective isolation and activation of bloodcells remains to be done.

Effectiveness of continuous arteriovenous hemofiltration (CAVH) for the severe chronic hemodialysis patient : Takayama T, Yokoyama H, Torii Y, et al. Jpn J Acute Med 1988;12:721–726

Effectiveness of continuous arteriovenous hemofiltration (CAVH) for the severe chronic hemodialysis patient : Takayama T, Yokoyama H, Torii Y, et al. Jpn J Acute Med 1988;12:721–726

Correction of severe hyponatraemia by continuous arteriovenous haemofiltration before liver transplantation.

2 observations. Resultats satisfaisants 10 et 13 mois apres la transplantation (chez des femmes adultes)

Clinical experience of pumped arteriovenous haemofiltration in the management of patients in oliguric renal failure following cardiothoracic surgery

Pumped continuous arteriovenous haemofiltration offers a means of managing oliguric renal failure. We report our experience with the use of this technique in the management of patients with oliguric renal failure complicating cardiothoracic surgery, and conclude that it allows management of this complication without transfer to a renal unit.