Acute renal failure after right nephrectomy for spontaneous rupture and left renal vein ligature.
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Acute Kidney Injury↗
Biomedical subjects
P Ravani
Publications and source records attributed to P Ravani.
How to improve dialysis adequacy in patients with vascular access problems.
Blood flow rate is a critical factor in the achievement of an adequate dialysis dose. The aim of this review is to evaluate the possibility of optimizing dialysis dose in terms of Kt/V in patients with reduced vascular access (VA) flow rate, considering effective blood flow (Qb eff), recirculation, access flow and hemodialyzer. In patients where the achievement of adequate blood flow rates are difficult to obtain and no surgical revision is necessary, to avoid under dialysis the increase in the treatment time should be the first choice solution. If such a solution is difficult for various reasons, a forced partial blood flow recirculation, especially in central venous catheters (CVCs) with reversed lines can be useful, on condition that the dialysis session is prolonged. The possibility of increasing the efficiency of dialysis through an increase in filter clearance has to be considered. Monitoring arterial pre-pump pressure (P asp) and optimizing ratio P asp/Qb eff during hemodialysis (HD) is one possible solution to improve blood flow rates, but it is necessary to educate and involve the staff. Recent developments in a new class of highly effective hemodialyzer due to dialysate distribution, has opened up interesting opportunities in terms of dialysis adequacy in patients with reduced VA flow rate.
Arteriovenous Shunt, Surgical↗
[Effect of an ambulatory program devoted to chronic renal insufficiency on the reduction of mobidity and hospitalization among patients at the beginning of dialysis treatment].
BACKGROUND: Late nephrological referral of end-stage renal disease (ESRD) patients is associated with increased risk of emergent dialysis start and poor complications control. However, the relative contribution of pre-dialysis care organization is unknown. METHODS: All 175 consecutive patients who started chronic dialysis for ESRD at our Institution from 1.1.99 to 30.6.02 were grouped as follows: referred ? 3 months before dialysis, (A, n=50); followed by non-dedicated specialists (B, n=74) or by pre-dialysis educational program personnel (PEP, n=51). We examined the first six months of hospitalization, uraemic complications control, type of dialysis initiation, and first dialysis modality. RESULTS: There was no difference in baseline characteristics and comorbidities among groups. PEP patients had higher creatinine clearance, haemoglobin, calcemia and BMI at initiation. They also made greater use of ACE-inhibitors and were more likely to have a planned start and choose peritoneal dialysis. Emergent starts were 50% (A 100%, B 45%, PEP 4%, p<0.001). Mean pre-dialysis hospitalization (due to in-patient emergency dialysis onset for unplanned starts and planned for access insertion for elective out-patient starts) was shorter among PEP patients (7days-PEP, 17days-B, 30days-A). Logistic regression confirmed the predictive role of PEP for emergent start (AOR 0.03, 0.001 to 0.101, p<0.001) even excluding late referrals (AOR 0.1, 0.033 to 0.306, p<0.001), independently of baseline characteristics and comorbidities. CONCLUSIONS: Pre-dialysis follow-up by dedicated personnel was more effective than traditional specialist care in reducing morbidity and health care resources utilization in patients starting dialysis.
Adult↗
[Disturbances of mineral metabolism and vascular calcifications in dialysis patients (review)].
Vascular calcifications are more frequent in dialysis patients than in the general population or in patients with cardiovascular disease and normal renal function. The reasons for this high incidence are multiple. They include traditional factors such as hypertension, diabetes, dyslipidaemia, and specific factors such as sodium overload, hyperomocysteinaemia, chronic inflammation, oxidative stress as well as disturbance of mineral metabolism. Specifically, hyperphosphataemia and the elevated calcium (Ca) x phosphate product have been associated with an increased risk for development of vascular calcification and death. Even though a causal relationship between the use of Ca- containing phosphate binders and the development of vascular calcifications has not been documented, treatment with Ca salts can induce hypercalcaemia, increased Ca x phosphate product, and Ca overload. A net intestinal Ca absorption of 180-500 mg has been documented in uraemic patients after a meal containing 1200 mg of Ca. Thus, treatment with Ca salts may induce Ca overload when a patient is dialyszed against a high dialysate Ca (> 1.5 mmol/L) solution, which is known to determine a positive dialysis balance. On the contrary, an overall negative Ca balance can result from the use of a low Ca dialysate (1.25 mmol/L) when the patients do not receive Ca supplements or vitamin D metabolites. Maintaining a normal Ca and phosphate balance remains one of the primary goals in the management of dialysis patients. Control of hyperphopshataemia should be obtained using either Ca and aluminium- free phosphate binders, such as sevelamer, or Ca salts, while avoiding a daily oral elemental Ca intake > 1.5 g.
Calcinosis↗
[Control of calcium and phosphate metabolism and prevention of vascular calcifications in uremic patients].
Vascular calcifications are more frequent in dialysis patients than in the general population or in patients with cardiovascular disease (CVD) and normal renal function. The reasons for this high incidence are multiple; they include traditional factors such as hypertension, diabetes, dyslipidemia, and specific factors such as sodium overload, hyperomocysteinemia, chronic inflammation and oxidative stress, as well as mineral metabolism disturbances. Specifically, hyperphosphatemia and the elevated calcium (Ca) x phosphate product have been associated with an increased risk for the development of vascular calcification and death. Treatment with Ca salts can induce hypercalcemia, increased Ca x phosphate product and Ca overload. Sevelamer substitution for Ca salts has been documented to attenuate the progression of coronary artery and aortic calcification. A possible mechanism explaining this observation could be ongoing Ca loading related to oral Ca ingestion. Treatment with Ca salts could induce Ca overload, particularly in patients dialyzed against a high dialysate Ca (>1.5 mmol/L) solution, which is known to determine a positive dialysis balance. Conversely, an overall negative Ca balance can result from low Ca dialysate use (1.25 mmol/L) when the patients do not receive Ca supplements or vitamin D metabolites. Maintaining normal Ca and phosphate balances remains a primary goal in the management of dialysis patients. Control of hyperphopshataemia should be achieved either using Ca and aluminum-free phosphate binders, such as sevelamer, or Ca salts, alone or in combination, provided that a daily oral elemental Ca intake of 1.5 g is not exceeded.
Calcinosis↗
[Statistical models and multivariable analysis].
Most clinical research can be simplified as an investigation of an input/output relationship. The inputs are called explanatory (independent) variables or predictors and are thought to be related to the outcome, or response (independent) variable. This relationship is usually complicated by other factors related to both the input and the output (presence of confounding) and can vary according to the levels of the other variables (presence of interaction). This input/output relationship is usually described by statistical models that include a fit part and a residual component or difference between the data and the fit. The most popular models are the general linear models, which can be considered the paradigm of all models used in multi-variable analyzes.
Biomedical Research↗
[Introduction of the general linear models].
General linear models can be considered the paradigm of all models used in clinical epidemiology. In these models, the independent variables combine in linear fashion to predict the values of the variable response. Since no model predicts the variable response perfectly, an error term is incorporated into the model to acknowledge what remains to be explained after getting a fit to the data. When this error term is normally distributed with constant variance, the linear models are reasonably appropriate to describe the input/output relationship of interest.
Linear Models↗
[Clinical relevance of study results].
The critical appraisal process of available evidence includes the evaluation of clinical importance of the study findings. This should coincide with the minimum worthwhile effect expected by the investigators in the study design and planning. In hard outcome studies it can be quantified by the absolute risk difference between groups and its reciprocal, known as number needed to treat to avoid one adverse event, or benefit (NNTB). The number needed to treat to produce harmful consequences of treatment (NNTH) should also be taken into account. Finally these effect measures, like risks and incidence proportions, are usually rough estimates of the true effects, due to non-complete follow-up of the observations under study. Underlying assumptions and design issues are especially important to assess the clinical relevance of any results.
Clinical Trials as Topic↗