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Biomedical subjects

David J Carr

Publications and source records attributed to David J Carr.

4 recordsLinked to original sources
PubMed2006

Sorbent suspensions vs. sorbent columns for extracorporeal detoxification in hepatic failure.

Hepatic failure is a significant medical problem which has been unsuccessfully treated by hemodialysis. However, similar therapies using recirculated dialysate regenerated by sorbents in place of single-pass dialysate have been beneficial in treating acute-on-chronic liver failure. The advantages of sorbent-based treatments include some selectivity of toxin removal and improved removal of protein-bound toxins. Activated carbon has been extensively used in detoxification systems, but has often had insufficient toxin capacity. Powdered activated carbon, because of its large surface area, can provide greater binding capacity for bilirubin and other toxins than granular carbon commonly used in detoxifying columns. Methods of using powdered carbon in extracorporeal blood treatment devices are reviewed in the present paper, including liver dialysis and a new sorbent suspension reactor (SSR); and the abilities and limitations of the SSR and columns to process protein solutions are discussed.

Carbon↗
PubMed2002

Treatment of severe tricyclic antidepressant overdose with extracorporeal sorbent detoxification.

Tricyclic overdose can be a medical emergency, and therapy with intravenous bicarbonate is not always successful in preventing cardiac toxicity or coma. Mortality in patients developing these complications is from 1% to 15%. Extracorporeal detoxification with sorbents has been used in treatment of patients with very high drug levels and declining clinical condition. Ten patients with serious drug overdose caused by tricyclics failed to respond quickly to standard therapy and were in stage 3-4 encephalopathy. Nine of these patients were on respirator support, 5 had hypotension, and 6 had QRS widening. Average level was 1,423 microg/L at presentation. Enteral activated charcoal and intravenous (IV) bicarbonate were initiated in the emergency room. The patients were treated for 3 to 4 hours with the Liver Dialysis Unit, a hemodiabsorption device using a cellulosic plate dialyzer and sorbent suspension as dialysate. Inflow and outflow blood levels indicated that the hemodetoxifier removed modest amounts of the tricyclics, metabolites, and other consumed drugs. The clinical improvement of the patients was dramatic, with patients reaching stage 0 or 1 encephalopathy during the treatment. Ventilator support was removed at the end of treatment for 3 patients who had not already developed pneumonia, and for others was prolonged up to 48 hours because of pneumonia, rather than mental status. Average length of stay in the intensive care unit (ICU) was 4.8 days (range 1 to 7 days). None of the patients died despite their high risk for ventricular arrhythmias, seizures, and death. Clinical improvement may have been attributable to removal of free drug from the blood or to removal of drug metabolites.

Antidepressive Agents, Tricyclic↗
PubMedDate not supplied

Predicting dialysate sodium composition in sorbent dialysis using single point and multiple-dilution conductivity measurement.

This research establishes the ability to predict the sodium composition in dialysate from a single conductivity measurement over the wide range of concentrations of chloride, bicarbonate, and acetate that occur during sorbent dialysis. The ranges explored in mEq/L were sodium 100-180, chloride 76-143, bicarbonate 16-31, and acetate 4-11. Through mathematical optimization using a pattern search method, a single point measurement technique was shown to predict the total sodium concentration within approximately +/- 4.2 mEq/L in solutions with varying relative concentrations of chloride, bicarbonate, and acetate. The data analysis showed that the total sodium concentration can be predicted within +/- 2.1 mEq/L in most cases. Another potential approach to determining sodium concentration, a multiple-dilution measurement method, was tested and is also described. It is based on the varying relationship of activity to concentration for each of the sodium-anion pairs. This technique has practical limitations because of interactions between the various ions in solution at normal concentrations of dialysis along with the complexities involved in creating high dilutions of dialysate for on-line assays during dialysis.

Biometry↗