Dialysis Reactions

Hospitalization for Initiation of Maintenance Hemodialysis

BACKGROUND

Recent data on complications of hemodialysis (HD) is lacking. With advancement in dialysis technology the incidence of complications such as dialysis disequilibrium syndrome (DDS) has decreased. Notwithstanding these improvements many patients with end-stage renal disease (ESRD) continue to be hospitalized solely for initiation of hemodialysis. This study was undertaken to assess if such admissions are justified and also to determine incidence and predictors of complications of HD during initiation.

METHODS

Medical records of adult patients (>18 years) initiated on maintenance hemodialysis from January 1st, 1998 through December 31st, 2000 at our institution were reviewed. The demographics of the patients, cause of renal failure, creatinine clearance, type of vascular access, comorbidities, serum chemistries, ultrafiltration (UF) rate and indications for initiating dialysis were noted. Intradialytic complications were retrieved from the dialysis flow sheets.

RESULTS

Of the 240 patients reviewed, 18.3% developed complications during initiation of dialysis, and none was severe. Hypotension and leg cramps were the most frequent complications. The patients who developed hypotension and cramps were significantly older than those with no complications, 57.7 +/- 14.9 (mean +/- SD) years versus 52.3 +/- 14.8 years, respectively (p = 0.02). The increment of age significantly influenced the complication rate [odds ratio (OR): 1.03, 95% confidence interval (CI) 1.01-1.05 (p = 0.03)], and so did hematocrit (HCT) (OR: 1.07, 95% CI 1.01-1.13). Multivariate analysis using age and hematocrit as continuous variables revealed that the older patients with anemia had a significantly higher risk of developing HD related complications than younger patients with anemia (OR: 1.05, 95% CI 1.01-1.09 at HCT of 24%, and OR: 1.03, 95% CI 1.00-1.06 at HCT 27%). When patients were stratified by hematocrit level, older patients with hematocrit <27% had higher risk of complications and the risk increased with increasing age [complication rate (HCT <27%): age <40 = 0%, age 40-64 = 11.7%, age >65 = 25%, p < 0.016].

CONCLUSION

Although very few, hypotension and muscle cramps were the main complications during initiation of HD. Older patients with anemia are prone for these complications although no physician intervention was necessary. Hospitalization solely for initiation of maintenance dialysis is not necessary and the additional cost from such admissions cannot be justified.

Impact of intermittent hemodialysis variables on clinical outcomes in acute renal failure

When hospital-acquired acute renal failure (ARF) is severe enough to require renal replacement therapy, mortality rates are extremely high, exceeding 50%. The potential impact of renal replacement therapy on clinical outcomes in ARF remains a subject of ongoing investigation and controversy. This article reviews in depth all of the clinical trials that have examined the effect of dialysis-related variables on clinical outcomes in patients with ARF requiring intermittent hemodialysis. In particular, the role of biocompatibility of dialyzer membranes, and timing, intensity, and adequacy of dialysis are discussed.

Activation of the kallikrein-kinin system in hemodialysis: role of membrane electronegativity, blood dilution, and pH

BACKGROUND

The kallikrein-kinin system activation by contact with a negatively charged surface has been promulgated to be responsible for hypersensitivity reactions. However, to explain the low frequency and heterogeneity of hypersensitivity reactions, we hypothesized that not only the electronegativity of the membrane, but also other physicochemical parameters could influence the activation of the contact phase system of plasma assessed by the measurement of kallikrein activity and bradykinin concentration.

METHODS

Plasma kallikrein activity using chromogenic substrate (S2302) and plasma bradykinin concentration (enzyme immuno assay) were measured during the perfusion of human plasma (2.5 ml/min) through minidialyzers mounted with six different membranes [polyacrylonitrile (PAN) from Asahi (PANDX) and from Hospal (AN69), polymethylmethacrylate (PMMA) from Toray, cellulose triacetate (CT) from Baxter, cuprophane (CUP) from Akzo and polysulfone (PS) from Fresenius].

RESULTS

A direct relationship was shown between the electronegativity of the membrane assessed by its zeta potential and the activation of plasma during the first five minutes of plasma circulation. With the AN69 membrane, the detection of a kallikrein activity in diluted plasma but not in undiluted samples confirmed the importance of a protease-antiprotease imbalance leading to bradykinin release during the first five minutes of dialysis. With PAN membranes, the use of citrated versus heparinized plasma and the use of various rinsing solutions clearly show a dramatic effect of pH on the kallikrein activity and the bradykinin concentration measured in plasma. Finally, increasing the zeta potential of the membrane leads to a significant increase of plasma kallikrein activity and bradykinin concentration.

CONCLUSIONS

Our in vitro experimental approach evidences the importance of the control of these physicochemical factors to decrease the activation of the contact system.