Search PubMed⌕ Search

Biomedical subjects

R Bellomo

Publications and source records attributed to R Bellomo.

250 records · Page 14Linked to original sources

Low-dose dopamine in patients with early renal dysfunction: a placebo-controlled randomised trial. Australian and New Zealand Intensive Care Society (ANZICS) Clinical Trials Group.

BACKGROUND: Low-dose dopamine is commonly administered to critically ill patients in the belief that it reduces the risk of renal failure by increasing renal blood flow. However, these effects have not been established in a large randomised controlled trial, and use of dopamine remains controversial. We have done a multicentre, randomised, double-blind, placebo-controlled study of low-dose dopamine in patients with at least two criteria for the systemic inflammatory response syndrome and clinical evidence of early renal dysfunction (oliguria or increase in serum creatinine concentration). METHODS: 328 patients admitted to 23 participating intensive-care units (ICUs) were randomly assigned a continuous intravenous infusion of low-dose dopamine (2 microg kg(-1) min(-1)) or placebo administered through a central venous catheter while in the ICU. The primary endpoint was the peak serum creatinine concentration during the infusion. Analyses excluded four patients with major protocol violations. FINDINGS: The groups assigned dopamine (n=161) and placebo (n=163) were similar in terms of baseline characteristics, renal function, and duration of trial infusion. There was no difference between the dopamine and placebo groups in peak serum creatinine concentration during treatment (245 [SD 144] vs 249 [147] micromol/L; p=0.93), in the increase from baseline to highest value during treatment (62 [107] vs 66 [108] micromol/L; p=0.82), or in the numbers of patients whose serum creatinine concentration exceeded 300 micromol/L (56 vs 56; p=0.92) or who required renal replacement therapy (35 vs 40; p=0.55). Durations of ICU stay (13 [14] vs 14 [15] days; p=0.67) and of hospital stay (29 [27] vs 33 [39] days; p=0.29) were also similar. There were 69 deaths in the dopamine group and 66 in the placebo group. INTERPRETATION: Administration of low-dose dopamine by continuous intravenous infusion to critically ill patients at risk of renal failure does not confer clinically significant protection from renal dysfunction.

Analysis of Variance↗

Acute renal failure in critical illness. Conventional dialysis versus acute continuous hemodiafiltration.

The dialytic therapy of choice in critically ill patients with acute renal failure (ARF) is a matter of controversy. The clinical outcome of such patients managed with either conventional dialytic therapy (CDT) or acute continuous hemodiafiltration (ACHD) was compared through retrospective review of medical records from the intensive care unit of a tertiary institution. Records from 167 critically ill patients with ARF consecutively treated in the same intensive care unit were reviewed. Eighty-four patients with ARF treated by CDT were compared to 83 treated with ACHD. The etiology of ARF and the degree of illness severity were similar in both groups (failing organs: CDT 3.9 vs. ACHD 4.1; mean APACHE II score: CDT 25.8 vs. ACHD 28.1). Overall survival was 29.8% for the CDT patients and 41% for the ACHD group (NS). In those with two to four failing organs, survival was greater in the ACHD group (53.8% vs. 31.1%; p < 0.025). This was also true for patients with an intermediate APACHE II score (24-29) who demonstrated better survival when treated by ACHD (46.4% vs. 12.5%; p < 0.025). Acute continuous hemodiafiltration was associated with better control of azotemia and hyperphosphatemia and increased nutritional intake. This retrospective study suggests that ACHD may offer clinically significant advantages over CDT, particularly in patients with an intermediate degree of critical illness severity.

Acute Kidney Injury↗

Imaging studies in partial epilepsy in children and adolescents.

We reviewed the results of imaging studies on 111 children and adolescents with partial epilepsy to determine which imaging procedure had the greatest sensitivity and specificity for partial epilepsy in this age range. All cases were classified as idiopathic, lesional, and cryptogenic epilepsy based on the 1989 International League Against Epilepsy Classification. All patients had magnetic resonance imaging (MRI) and 98 also had computed tomography (CT). Thirty patients with negative CT had MRI lesions that were most likely the cause of the epilepsy, and the initial diagnosis of cryptogenic partial epilepsy was changed to lesional partial epilepsy. We concluded that CT use is unwarrantedly common. MRI should be considered the procedure of first choice. CT has a complementary role, and functional neuroimaging should be encouraged.

Adolescent↗

A prospective study of continuous venovenous hemodiafiltration in critically ill patients with acute renal failure.

UNLABELLED: We studied the biochemical and the clinical consequences of the application of continuous venovenous hemodiafiltration to the management of acute renal failure in critically ill patients. One hundred consecutive surgical and medical ICU patients with acute renal failure were entered into a prospective clinical study at an intensive care unit of tertiary institution. INTERVENTION: included assessment of illness severity by APACHE II score on admission and by organ failure score prior to initiation of renal replacement therapy; treatment of patients with continuous venovenous hemodiafiltration; and measurement of biochemical variables prior to and after therapy. Outcome assessment included incidence of complications, duration of oliguria, duration of intensive care and hospital stays, and survival to hospital discharge. MEASUREMENTS AND MAIN RESULTS: included the following: mean patient age was 60.9 years (range 21-81 yr); mean APACHE II score, 28.6 (95% confidence interval; 27.4-29.8); and number of failing organs, mean, 4.1 (95% confidence interval; 3.8-4.4). At commencement of continuous venovenous hemofiltration with dialysis, 79% of patients were receiving inotropic drugs and 72% were septic, and, in 35%, bacteremia or fungemia was demonstrated. Renal replacement therapy was applied for a mean duration of 186.2 hours (95% confidence interval; 149.2-223.7), with a mean hourly net ultrafiltrate production of 621 mL (95% confidence interval; 594-648) and a mean urea clearance of 28.1 mL/min (95% confidence interval; 26.7-29.5). Azotemia was controlled in all patients (plasma urea < 30 mmol/L). During the more than 18,000 hours of treatment, there was no therapy-associated hemodynamic instability. Complications were rare. They included two cases of hemofilter rupture with minor blood loss and a single case of bleeding at the site of the vascular-access catheter. Forty-three patients survived to ICU discharge, and 40 survived to hospital discharge. Continuous venovenous hemodiafiltration is a safe and an effective form of renal replacement therapy in critically ill patients. In such patients, who have a high predicted mortality rate, it was associated with a 40% survival rate. These findings suggests that continuous venovenous hemodiafiltration may be ideally suited to patients with multisystem organ failure with acute renal failure.

APACHE↗

Brain density changes during renal replacement in critically ill patients with acute renal failure. Continuous hemofiltration versus intermittent hemodialysis.

Computerized tomography (CT) studies of the brain were made on 12 patients with acute renal failure from different origin. Patients were treated for two subsequent days in random sequence with intermittent hemodialysis (HD) (one 4-h session and Kt/V > or = 1) and continuous veno-venous hemofiltration (CVVH) (one 24-h session and Kt/V > or = 1). CT scans were done before and after the HD and CVVH session in each patient. In baseline conditions, the only macroscopic morphological alteration was a slight brain edema in some patients. Significant changes in the density of white and gray matter were observed after the HD session in all patients (gray matter from 52.3 +/- 5.2 to 38.9 +/- 5.3 and white matter from 36.7 +/- 3.5 to 24.8 +/- 3.2 Hounsfield units, average delta -26.7%). No changes were observed after CVVH. We conclude that intermittent HD involves a remarkable degree of "unphysiology", leading to increased water content in the brain after each session. In acute patients this may lead to a post-dialytic brain edematogenic state. The physiological stability provided by continuous therapies such as CVVH avoids this unwanted effect, and suggests that continuous renal replacement therapies should be a first choice in these patients.

Acute Kidney Injury↗

Cellulose triacetate: another membrane for continuous renal replacement therapy.

The evolution of technology and biomaterials has permitted a parallel development of renal replacement therapies in the acute, critically ill patient. From the original continuous artero-venous hemofiltration method new techniques such as continuous veno-venous hemofiltration, hemodiafiltration and high-flux dialysis have been developed and are clinically used. Similar progress has been made with artificial membranes. We investigated the possibility of using a modified cellulosic membrane for continuous therapies, assessing the hydraulic characteristics and clearance performances of high-flux cellulose triacetate hemodiafilter (0.7 m2) in vitro and in vivo. The flowdynamic characteristics of the filter suggest its optimal use in veno-venous pump-drive techniques. Efficiency was excellent, with urea daily clearances as high as 50 liters or more. The high permeability and porosity of the membrane also increased the clearances of larger solutes such as creatinine and inulin. No side effects occurred during treatment and we conclude that cellulose triacetate may be considered a good alternative to synthetic membranes in continuous renal replacement therapies.

Acute Kidney Injury↗

[Long-term intermittent renal replacement therapy at an intensive care unit].

Standard intermittent hemodialysis (IHD) used for the treatment of acute renal failure (ARF) at an intensive care unit has significant biochemical and physiological drawbacks. In the past 20 years, these drawbacks have stimulated the development of continuous renal replacement therapy (CRRT) and its ever-increasing use. However, CRRT is technically complicated and requires 24-hour monitoring. In some clinics, the use of CRRT leads to that each patient is under his/her nurse's surveillance, instead 1 nurse per 2 patients as before; this change has economic consequences and may limit nursing accessibility to other patients. The procedures prolonging intermittent therapy do not require 24-hour monitoring may benefit the treatment of ARF at the intensive care therapy. In this paper the authors call such procedures for continuous intermittent renal replacement therapy. They are characterized by a number of basic principles: (1) the use of modified or standard dialysis apparatuses; (2) the application of diffuse, convection, or both; (3) a certain reduction in the rate of elimination of dissolved substances as compared with IHD; (4) more prolonged treatment: above usual 3 or 4 hours of IHD, but not more than 8-12 hours (hence the term "intermittent"); (5) the use of on-line generation dialysate or substituting fluid. Information on the effectiveness and safety of this procedure is being now compiled.

Acute Kidney Injury↗

[Rationale for the use of extracorporeal treatments for sepsis].

Sepsis is the leading cause of disability and mortality among critical patients; moreover, it causes high economic expenditures. Although very much is known about the pathophysiology of this condition and its mediators despite great investments directed to its control, mortality rates remain high. Recent treatment manuals emphasize the value of early goal-oriented therapy and also point to the high efficacy of activated protein C. Extracorporeal blood clearance may potentially become a new approach to treating this condition. There are reports on its positive clinical results that are likely associated with the effective removal of septic mediators. Human and animal studies, few and rather alike as they are, have yielded promising results. It is evident that the use of these procedures is justified; however, their efficiency in sepsis requires large-scale, correctly conducted studies.

Extracorporeal Circulation↗

Tumor necrosis factor clearances during veno-venous hemodiafiltration in the critically ill.

Tumor necrosis factor alpha (TNF) is a mediator of injury in the critically ill. Its small molecular size (17 kd) should allow its clearance during continuous hemodiafiltration (CHD). The authors studied TNF extraction in 12 critically ill patients (APACHE II score 26.3 mean; range, 19-34) receiving CHD. Tumor necrosis factor levels were measured in prefiltered and filtered blood and ultradiafiltrate at 0.4 and 24 hours of therapy. Before CHD, mean plasma TNF levels were 261 pg/ml (95% confidence interval [CI]: 184-578) and 291 pg/ml (95% CI: 0-589) after 24 hours. There were no statistically significant differences between prefilter and postfilter TNF levels. Most ultradiafiltrate samples (74%) contained demonstrable TNF (mean, 314 pg/ml; 95% CI: 67-561). Daily TNF excretion was a mean of 15.9 micrograms (+5.6 standard error [SE]), with a mean daily clearance of 27.5 L (95% CI: 2.5-52.5). The authors conclude that significant amounts of TNF are excreted in the ultradiafiltrate during CHD. This observation may provide a rationale for use of similar therapies in critically ill patients in the absence of conventional indications for dialytic support.

Critical Care↗

In vivo catecholamine extraction during continuous hemodiafiltration in inotrope-dependent patients.

Many critically ill patients require inotropic or vasopressor support to maintain adequate oxygen delivery. Removal of catecholamines by continuous hemodiafiltration (CHD) could alter exogenous catecholamine requirements. The authors have studied hemodynamic state, catecholamine clearances, and catecholamine requirements in 12 critically ill patients (mean APACHE II score, 24.5) receiving CHD. Hemodynamic parameters were assessed before CHD initiation, and at 4 and 24 hours of therapy. Simultaneous determinations of serum and ultradiafiltrate dopamine (D), norepinephrine (NE), and epinephrine (E) concentrations were obtained. There were no significant changes in any of many hemodynamic parameters measured during CHD. Mean catecholamine requirements were not altered by CHD. Plasma catecholamine levels were not significantly affected by CHD (mean values at 0, 4, and 24 hours: D: 10,801, 12,056, and 8,797 pg/ml; NE: 1124, 566, and 926 pg/ml; E: 1,420, 1,383, and 843 pg/ml). Catecholamine clearances from CHD (D:43.7 ml/min; NE: 43.5 ml/min; and E: 46.6 ml/min) resulted in daily excretion of only 379 micrograms D, 32.9 micrograms NE, and 37.2 micrograms E. Clearances of catecholamines by CHD represented a daily loss of less than 0.1% of the administered load. In conclusion, although CHD can remove circulating catecholamines, cumulative daily catecholamine extraction is minimal in pharmacologic terms, and has no impact on hemodynamic status.

Acute Kidney Injury↗

Continuous venovenous hemodiafiltration compared with conventional dialysis in critically ill patients with acute renal failure.

The morbidity and mortality benefits of new forms of continuous renal replacement therapy remain controversial. The authors have compared a cohort of consecutive prospectively studied critically ill patients with acute renal failure treated with continuous venovenous hemodiafiltration (CVVHD) (n = 76) to a previously described antecedent group of patients treated in intensive care with intermittent hemodialysis or peritoneal dialysis (conventional dialysis [CD]) (n = 84). Patients were comparable for mean age, gender distribution, and mean number of failing organs (CVVHD: 4; CD: 3.9). CVVHD patients were more severely ill as measured by APACHE II score (CVVHD: score of 29; CD: score of 25.8). Despite their greater illness severity, CVVHD patients more often survived to hospital discharge (CVVHD: 40.8%) than did CD patients (CD: 29.8%; NS). After adjustment for illness severity, in patients with two, three, or four failing organs, survival was 54.3% for CVVHD versus 29.3% for CD (p < 0.01). Survival was 48% for CVVHD patients with an intermediate APACHE II score (24 to 29), compared with 12.5% for comparable CD patients (p < 0.01). No statistically significant differences were seen at either extreme of illness severity. Complications were significantly fewer during CVVHD (1 vs. 18). These data support the view that CVVHD reduces morbidity and mortality in critically ill patients with acute renal failure.

Acute Kidney Injury↗