ABSTRACT
A potential application of the continuous renal replacement therapies is the extracorporeal removal of inflammatory mediators in septic patients. Cytokine elimination with continuous renal replacement therapies has been demonstrated in several clinical studies, but so far without important effects on their serum concentrations. Improved knowledge of the cytokine removal mechanisms could lead to the development of more efficient treatment strategies. In the present study, 15 patients with septic shock and acute renal failure were observed during the first 24 h of treatment with continuous venovenous hemofiltration (CVVH) with an AN69 membrane. After 12 h, the hemofilter was replaced and the blood flow rate (QB) was switched from 100 ml/min to 200 ml/min or vice versa. Pre- and postfilter plasma and ultrafiltrate concentrations of selected inflammatory and anti-inflammatory cytokines were measured at several time points allowing the calculation of a mass balance. Cytokine removal was highest 1 h after the start of CVVH and after the change of the membrane (ranging from 25 to 43% of the prefilter amount), corresponding with a significant fall in the serum concentration of all cytokines. The inhibitors of inflammation were removed to the same extent as the inflammatory cytokines. Adsorption to the AN69 membrane appeared to be the main clearance mechanism, being most pronounced immediately after installation of a new membrane and decreasing steadily thereafter, indicating rapid saturation of the membrane. A QB of 200 ml/min was associated with a 75% increase of the ultrafiltration rate and a significantly higher convective elimination and membrane adsorption than at a QB of 100 ml/min. The results indicate that optimal cytokine removal with CVVH with an AN69 membrane could be achieved with a combination of a high QB/ultrafiltration rate and frequent membrane changes.
Subject(s)
Cytokines/blood , Hemofiltration/instrumentation , Shock, Septic/blood , Shock, Septic/therapy , Adult , Aged , Analysis of Variance , Bacteremia/blood , Bacteremia/diagnosis , Bacteremia/mortality , Bacteremia/therapy , Female , Follow-Up Studies , Hemodynamics , Hemofiltration/methods , Humans , Male , Micropore Filters , Middle Aged , Prospective Studies , Respiratory Function Tests , Shock, Septic/diagnosis , Shock, Septic/mortality , Statistics, Nonparametric , Survival Rate , Treatment OutcomeSubject(s)
Renal Replacement Therapy , Sepsis/therapy , Acute Kidney Injury/physiopathology , Acute Kidney Injury/therapy , Animals , Hemodynamics , Humans , In Vitro Techniques , Inflammation Mediators/blood , Inflammation Mediators/isolation & purification , Multiple Organ Failure/physiopathology , Multiple Organ Failure/therapy , Respiration , Sepsis/physiopathologyABSTRACT
Elevated serum levels of homocysteine, a sulphur-containing amino acid, are increasingly recognized as an independent risk factor for atherosclerotic and thrombotic vascular disease. Presence of a thermolabile variant of methylenetetrahydrofolatereductase and an inadequate folate status are the most common causes of hyperhomocysteinaemia. Homocysteine damages the vessel wall mainly through generation of oxygen radicals and creates a prothrombotic environment. In the majority of cases, normalization of homocysteine levels can be achieved with administration of vitamins of the B-group. The effect of this treatment on cardiovascular outcome, however, remains undefined.
Subject(s)
Cardiovascular Diseases/etiology , Hyperhomocysteinemia/complications , Arteriosclerosis/etiology , Cardiovascular Diseases/complications , Cardiovascular Diseases/metabolism , Clinical Trials as Topic , Controlled Clinical Trials as Topic , Female , Humans , Hyperhomocysteinemia/drug therapy , Hyperhomocysteinemia/epidemiology , Hyperhomocysteinemia/metabolism , Incidence , Male , Risk Factors , Thrombosis/etiology , Vitamins/therapeutic useABSTRACT
This study aimed to examine the changes in RR interval and blood pressure (BP) variability and humoral factors during postural changes in borderline arterial hypertension. Twenty-nine patients (44 +/- 3 year; BP, 145 +/- 3/84 +/- 3 mm Hg) with borderline hypertension and a control group of 38 subjects (35 +/- 2 year; BP, 123 +/- 3/70 +/- 2 mm Hg) underwent power spectrum analysis of RR interval and BP (low frequency (LF), 0.05 to 0.15 Hz; high frequency (HF), 0.15 to 0.40 Hz) in the supine and standing positions. Concentrations of plasma renin activity, angiotensin II, and aldosterone in supine and standing positions had been determined in the hypertensive group. Borderline hypertensives are characterized by higher oscillations of systolic and diastolic BP, but not of RR interval in the supine position versus the control group. Low frequency and HF components of systolic and diastolic BP expressed as absolute data are also significantly higher in borderline hypertensives. Moreover, standing tended to increase the LF/HF ratio of both RR interval and BP variability compared to controls. The standing position was able to further activate the LF but not the HF component of BP variability. In borderline hypertension renin release during postural changes correlated well with the decrease in the power of the HF vagal component of RR interval variability (r = -0.70, P < .001) and with the increase of the LF component of diastolic blood pressure variability (r = 0.43, P = .03). In conclusion, our results indicate that in borderline arterial hypertension, LF and HF oscillations of BP are already significantly increased at rest.(ABSTRACT TRUNCATED AT 250 WORDS)
