Biomedical subjects

Nigel Fealy

Publications and source records attributed to Nigel Fealy.

4 recordsLinked to original sources

PubMed2005

Myoglobin clearance by super high-flux hemofiltration in a case of severe rhabdomyolysis: a case report.

OBJECTIVE: To test the ability of a novel super high-flux (SHF) membrane with a larger pore size to clear myoglobin from serum. SETTING: The intensive care unit of a university teaching hospital. SUBJECT: A patient with serotonin syndrome complicated by severe rhabodomyolysis and oliguric acute renal failure. METHOD: Initially continuous veno-venous hemofiltration was performed at 2 l/hour ultrafiltration (UF) with a standard polysulphone 1.4 m2 membrane (cutoff point, 20 kDa), followed by continuous veno-venous hemofiltration with a SHF membrane (cutoff point, 100 kDa) at 2 l/hour UF, then at 3 l/hour UF and then at 4 l/hour UF, in an attempt to clear myoglobin. RESULTS: The myoglobin concentration in the ultrafiltrate at 2 l/hour exchange was at least five times greater with the SHF membrane than with the conventional membrane (>100,000 microg/l versus 23,003 microg/l). The sieving coefficients with the SHF membrane at 3 l/hour UF and 4 l/hour UF were 72.2% and 68.8%, respectively. The amount of myoglobin removed with the conventional membrane was 1.1 g/day compared with 4.4-5.1 g/day for the SHF membrane. The SHF membrane achieved a clearance of up to 56.4 l/day, and achieved a reduction in serum myoglobin concentration from >100,000 microg/l to 16,542 microg/l in 48 hours. CONCLUSIONS: SHF hemofiltration achieved a much greater clearance of myoglobin than conventional hemofiltration, and it may provide a potential modality for the treatment of myoglobinuric acute renal failure.

Acute Kidney Injury↗

PubMed2003

Continuous is not continuous: the incidence and impact of circuit "down-time" on uraemic control during continuous veno-venous haemofiltration.

OBJECTIVE: There is little information on the duration of time that patients spend off therapy (down-time) during continuous veno-venous haemofiltration (CVVH) and the effect of this treatment free time on azotaemic control. DESIGN AND SETTING: Prospective observational study in the ICU of tertiary hospital. PATIENTS AND PARTICIPANTS: 48 critically ill patients treated with CVVH at 2 l/h of ultrafiltration. INTERVENTIONS: Prospective collection of demographic and biochemical data. MEASUREMENTS AND RESULTS: Two hundred and sixty-six filters were observed. Start and end times were collected for each filter. Creatinine and urea were measured daily and percentage of reduction of these two solutes was calculated (%Delta creatinine and urea). The median period when CVVH was not applied to a patient (down-time) was 3 h per day. There was a significant inverse correlation between down-time and %Delta creatinine and urea over each 24-h time cycle. On average at least 16 h per day of CVVH was required to maintain creatinine and urea concentration for each 24-h cycle. CONCLUSIONS: "Continuous" therapy is not truly continuous. Down-time adversely affects azotaemic control. Physicians prescribing CRRT should be aware of the consequences of such down-time on the quality and quantity of renal replacement therapy delivered.

Aged↗

PubMed2003

Pre-dilution vs. post-dilution during continuous veno-venous hemofiltration: impact on filter life and azotemic control.

BACKGROUND/AIMS: To determine the impact of replacement fluid infusion site on filter life and azotemic control during continuous veno-venous hemofiltration (CVVH). METHODS: Pre-dilution CVVH was conducted from February 2001 to December 2001 and then practice was changed to post-dilution (from January 2002 to July 2002). Filter life was prospectively observed and the following data obtained for each filter: starting date and time, ending date and time, heparin use, heparin dose and protamine use. Daily creatinine, urea, INR, APTT and platelet count were also collected. RESULTS: Forty-eight patients were studied (33 in pre-dilution and 15 in post-dilution) for a total of 309 filters (202 in pre-dilution and 107 in post-dilution). The median filter life was significantly shorter in the post-dilution period (18.0 vs. 13.0 h, p = 0.021). Multivariate linear regression analysis showed that pre-dilution was a significant independent predictor of increased filter life (p = 0.029), together with platelet count (p = 0.0035) and heparin dose (p = 0.046). There was no significant improvement in daily creatinine and/or urea reduction in the post-dilution period (% Delta creatinine: 7.9 vs. 10.2%/day, p = 0.99, urea: 5.4 vs. 9.7%/ day, p = 0.78). CONCLUSIONS: Post-dilution was associated with reduced filter life without any beneficial effect on daily changes in urea and creatinine levels. Pre-dilution appears a preferable technical approach to CVVH.

Acute Kidney Injury↗

PubMedDate not supplied

Continuous venovenous hemofiltration without anticoagulation.

We conducted a prospective observational study to assess the efficacy of continuous venovenous hemofiltration (CVVH) with no anticoagulation. A standard anticoagulation protocol for CVVH, which prescribed no anticoagulation for patients at risk of bleeding, was applied to 48 critically ill patients treated with CVVH. Circuit life was prospectively observed, and the following data were obtained for each circuit: heparin use and dose, protamine use, daily prothrombin time-international normalized ratio, activated partial thromboplastin time, and platelet count. Out of 300 consecutive circuits, 143 (47.6%) received no anticoagulation, 31 (10.3%) received regional anticoagulation, and 126 received low dose heparin. No patients experienced bleeding complications secondary to CVVH. Platelet count was significantly lower in the no anticoagulation group (73 x 10(3)/microl) compared with the low dose heparin group (119 x 10(3)/microl) and the protamine group (104 x 10(3)/microl) (p < 0.01 for both comparisons). There was no significant difference in mean circuit life among the three groups (heparin, 20.9 hours; no anticoagulation, 19.3 hours; protamine, 21.2 hours; not significant). In conclusion, for a group of patients deemed to be at risk of bleeding, CVVH without anticoagulation achieved an acceptable circuit life, which was similar to that obtained in other patients with low dose heparin anticoagulation or regional anticoagulation with heparin/protamine.

Acute Kidney Injury↗