Plasma atrial natriuretic factor (alpha ANF) during hemodialysis (HD) and hemofiltration (HF).

Plasma concentrations of immunoreactive alpha ANF were measured before, during, and after 3 hours of hemodialysis (HD) and hemofiltration (HF). In seven healthy subjects plasma alpha ANF concentrations were measured to serve as controls. Highly elevated pre-treatment alpha ANF levels were obtained in the HD group (286 +/- 52 pg/ml, mean +/- SE), and in the HF group (275 +/- 48 pg/ml) as compared with the controls (40 +/- 3 pg/ml). The effect of both HD and HF on the alpha ANF concentration was not significant after the first hour of treatment. However, a significant decrease was obtained after the second (HD = 244 +/- 49, HF = 140 +/- 17) and third hours (HD = 244 +/- 48, HF = 135 +/- 15) (p less than 0.05) in both treatments. A steeper decline in the alpha ANF concentration was notable during HF compared with HD. There was a significant difference (p less than 0.05) when both modalities were compared at the end of treatment. A correlation (r2 = 0.98, p less than 0.001) was noted between changes in the alpha ANF levels and the ultrafiltration (UF) volumes only during HF. Plasma alpha ANF concentrations at the filter outlet were lower than at the inlet in both groups. It is concluded that the plasma alpha ANF concentrations are highly elevated in chronic renal failure patients. Despite the decrease in these concentrations during HD and HF it did not reach the normal plasma level. Monitoring of plasma alpha ANF may be a useful indicator for the extracellular volume status during HD and HF treatments.     

Experience with vascular access for acute renal failure: using Buselmeier shunt and femoral vessel catheter

Three types of vascular access were evaluated over a period of 2 years, January 1987-December 1989, in 76 critically ill acute renal failure (ARF) patients. The Buselmeier shunt comprised 75% of the acute vascular access which were utilized, the cannulation of the femoral vessel 23% and the Scribner shunt 2%. The Buselmeier shunt was successfully used alone (mainly in the forearm) in 58 patients for continuous arteriovenous hemofiltration, continuous arteriovenous hemodialysis and intermittent hemofiltration. Thrombosis was noted in 7% of the shunts, where the majority needed a new shunt either on the same or the contralateral arm. Blood leakage was noted in 2%, hematoma in 1%, and accidental bleeding in 1% of the shunts. This study showed that the Buselmeier shunt is more used in our center, most likely because it is easy to bypass the hemodialysis filter by the staff nurse in case of clotting. No major complications were noted even if kept in place for a longer period of time. It offers adequate blood flow for continuous renal replacement therapy and intermittent hemofiltration in ARF.     

Identification of complement activators and elucidation of the fate of complement activation products during extracorporeal plasma purification therapy

It has been known for many years that the complement system is activated during extracorporeal plasma purification (ECCP) therapy. In a previous study, we showed that high concentrations of complement activation products (CAPs) are returned to the patient during immunoadsorption treatment. In the present study, we investigated the question of where complement activation takes place with different forms of ECPP equipments as well as the fate of the CAPs. Eleven patients (8 men and 3 women), mean age 52 ± 18 years, were included in the study. They were treated either with plasmapheresis (PP), immunoadsorption, bilirubin adsorption, or low density lipoprotein (LDL) apheresis. It was found that during all ECPP treatments and after the plasma separation filter, the plasma concentrations of CAPs were increased, and that high concentrations of CAPs were returned to the patients, except with PP. The plasma levels of individual CAPs varied between different types of ECPP. These variations were due to several factors: (1) complement activation (CA) on the plasma separator and a secondary device, e.g., column or membrane; (2) adsorption of specific CAPs to separation columns; and (3) reduction of CAPs due to separation and waste. Since CAPs have inflammatory and immunological effects, it is possible that high serum concentration of CAPs in the treated patients may influence the clinical outcome of the treatment. In conclusion, complement activation is a fact that should not be ignored during performance of any form of an ECPP. It is the plasma separator that plays a key role in the process of complement activation. Different ECPP treatments may have different effects regarding the levels of individual CAPs. J. Clin. Apheresis 13:167–173, 1998. © 1998 Wiley-Liss, Inc.     

Pharmacokinetics of intravenous imipenem/cilastatin during intermittent haemofiltration

The pharmacokinetics of a single iv dose of imipenem/cilastatin (500/500 mg) were studied during and after intermittent haemofiltration (IHF) treatment in six patients with chronic renal failure. The elimination half-lives of imipenem and cilastatin during the IHF treatment were almost identical, 1.4 +/- 0.3 and 1.5 +/- 0.3 h, respectively. Accordingly, approximately 75% of the given dose was eliminated during a 3-h IHF session. However, there was a great difference between the elimination half-lives of the two drugs in the post-treatment period, 3.4 +/- 1.0 and 16 +/- 10 h for imipenem and cilastatin, respectively. The haemofiltration clearance of imipenem was 134 +/- 41 ml/min and that of cilastatin 109 +/- 8 ml/min. On the basis of our results, we suggest that a supplementary dose of imipenem/cilastatin (500/500 mg) should be given directly after the IHF treatment. This dose should be the starting dose for a period of 12-h dosing intervals until the next IHF procedure.     

Continuous arteriovenous haemodialysis and haemofiltration in intensive care acute renal failure patients

CAVHD and CAVH were compared regarding uraemic control in 13 critically ill intensive care patients with acute renal failure (ARF). Patients’ mean age was 60 years. Pretreatment blood urea range was 17–56 mmol/l (33–56 mmol/l in 70% of the patients). All patients received vasopressor drugs, and 92% were on artificial mechanical respiration. From the results of this study both modalities gave adequate uraemic control. There was a notable decrease in the urea and creatinine levels with CAVHD more than with CAVH. There was no statistically significant difference between the two modalities in the urea clearance. However, a significant difference (P<0.05) in creatinine was obtained with CAVHD. Our results suggest that CAVHD is a useful alternative to CAVH in ARF especially when the blood urea level is >30 mmol/l. However, a higher dialysate flow rate (e.g. 25 ml/min) should be used if the urea level is more than 40 mmol/l. CAVH should be reserved for ARF patients in whom fluid overload is a major problem.     

Experience with the Hemasite device in haemodialysis and haemofiltration patients with vascular access problems

Multiple vascular access failure is a frequent problem and we report our experience with 32 Hemasite devices implanted in 28 patients with end-stage renal disease. All of the patients were on maintenance haemodialysis or haemofiltration with a range of treatment of 1-17 years. Their mean age was 58 +/- 14 years (range 28-72 years). The main indication for using this device as an alternative vascular access was the presence of high-risk patients with a high incidence of previous access failure (1-8 accesses per patient). The majority of the patients were considered as high risk, due either to old age (more than 60 years) (60%) or to the presence of diabetes mellitus (29%). The results of 5 years' experience and follow-up showed that the Hemasite device could be successfully used as a secondary vascular access in high-risk patients who have problems of multiple access failures. The 1-year cumulative survival of the device (55%) was affected by complications such as thrombosis and infection (47% and 16%) which were noted mostly among patients with diabetes mellitus. These complications are the major ones endangering the longevity of the Hemasite implant and were important causes of implant loss (31% and 6% respectively). Being needleless and painless, the Hemasite was well-accepted by the patients and it functioned well, with adequate blood flow. We conclude that the Hemasite device is a valuable alternative when vascular access becomes a problem in haemodialysis patients.