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B P Teehan

Publications and source records attributed to B P Teehan.

36 records · Page 2Linked to original sources
PubMed1983

Contribution of dialysate acetate to energy metabolism: metabolic implications.

During hemodialysis large amounts of acetate enter the bloodstream. Generally, it is assumed that this exogenous acetate load is oxidized immediately to carbon dioxide and water; however, the rate of plasma acetate oxidation and the effect of acetate oxidation on energy metabolism during hemodialysis has not been determined previously. The rates of plasma acetate turnover and oxidation were determined during hemodialysis in seven chronic renal failure patients by the primed continuous infusion of [1-14C] acetate. The plasma acetate turnover rate (57.2 +/- 2.9 mumoles/min X kg) agreed closely with the mass transfer rate of dialysate acetate into the bloodstream (55.3 +/- 3.2 mumoles/min X kg). Of the acetate entering the bloodstream, 54.5 +/- 5.2% or 31.6 +/- 3.77 mumoles/min X kg was oxidized immediately accounting for 40.3 +/- 4.8% of the patient's caloric expenditure. Although the oxidation of acetate during dialysis supplied a major portion of the patient's caloric need, a significant quantity of acetate was eliminated by pathways other than direct oxidation. An average overall respiratory quotient (RQ) of 1.0 +/- 0.02 indicated that fat oxidation was spared to maintain energy homeostasis during hemodialysis. The calculated non-protein RQ exceeded unity suggesting that net fat synthesis actually occurred.

Acetates↗
PubMed1983

Acetate and energy metabolism during hemodialysis.

The oxidation of acetate infused in acetate infused in large quantities during acetate dialysis should provide considerable energy for the hemodialysis patient. Previous attempts to measure acetate oxidation rate and thus energy yield by measuring bicarbonate generation rate are flawed because bicarbonate generation occurs by equimolar proton consumption when acetate is activated to acetyl Co-A but before acetyl Co-A has entered the Krebs cycle. Besides the Krebs cycle, acetyl Co-A could enter many other nonoxidative pathways. By using the primed continuous infusion radioisotope (1-14C acetate) dilution technique of Steele, in conjunction with indirect calorimetry, we obtained direct measurements of acetate turnover and immediate oxidation rates and energy yield in 7 stable hemodialysis patients. Commercial dialysate contained glucose (12.4 mmoles/liter), acetate (38 mmoles/liter), plus routine electrolytes. Acetate turnover was 57.2 +/- 2.9 mumoles/min X kg. Of the acetate entering the body, 31.6 +/- 3.8 mumoles/min X kg were immediately oxidized to carbon dioxide and water, which accounted for 54.4 +/- 5.2% of the turnover rate. The amount that entered the blood was 869 mmoles, and 472 mmoles (54.4%) were oxidized; 138 mmoles (15.8%) made up the steady-state pool, and 258 mmoles were directed into nonoxidative pathways (29.7%). During dialysis, 40.3 +/- 4.8% of the carbon dioxide output or metabolic rate was accounted for by acetate oxidation. Thus, acetate emerged as the major contributor to energy production, supplying up to 65% of the total caloric needs during dialysis. The RQ calculated from the lung carbon dioxide excretion was 0.74 +/- 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1980

Acid-base balance in continuous ambulatory peritoneal dialysis.

Metabolic acidosis was demonstrated in a group of anuric CAPD patients. Dialysate HCO3- loss was the major determinant of a negative base balance of 26.4 +/- 23.5 mMol/day. Bicarbonate supplementation corrected the acidosis. A primary respiratory alkalosis was also present in several patients.

3-Hydroxybutyric Acid↗
PubMed1978

Plasma pyridoxal-5'-phosphate levels and clinical correlations in chronic hemodialysis patients.

Plasma pyridoxal-5'-phosphate (PLP) was measured by a specific method in 45 stable, chronic hemodialysis patients and 13 normal adults. Despite oral pyridoxine supplements (1 to 5 mg/day) a majority (64%) of patients had low levels. The difference between normals (8.5 +/- 3.7 ng/ml) and dialysis patients (3.6 +/- 3.6 ng/ml) was significant at P less than 0.01. Plasma PLP appeared to decrease with increasing duration of time on dialysis therapy. In vivo clearance studies as well as pre- and postdialysis plasma levels indicated that PLP was not removed by the dialyzer. Mean plasma PLP levels were normal in patients with stable motor nerve conduction velocity and a low transfusion requirement and low in those with decreasing motor nerve conduction velocity or a high transfusion requirement but the difference between the means in each group was not statistically significant. High oral doses of pyridoxine (100 to 200 mg/day) but not low doses (1 to 5 mg/day) restored PLP levels to normal in a majority of patients after 2 weeks.

Adult↗
PubMedDate not supplied

Solute clearance in continuous venovenous hemodialysis. A comparison of cuprophane, polyacrylonitrile, and polysulfone membranes.

Critically ill patients with ARF and MOSF were treated with continuous venovenous hemodialysis (CVVHD). The BSM 22 delivery system (CGH Medical, Denver, CO) and four different dialyzer membranes were used. Vascular access was achieved with a dual lumen catheter placed percutaneously into a large vein. Heparin was used for anticoagulation, and commercially available peritoneal dialysis fluid was used as dialysate. At a fixed blood flow rate of 100 ml/min, the dialysate inflow and outflow rates were regulated to control azotemia and fluid balance. Blood side and dialysate side clearances for urea nitrogen, creatinine, bicarbonate, and lactate were measured. All dialyzer membranes studied provided high urea nitrogen clearance approximating dialysate outflow rate and resulting in excellent control of azotemia. Some of the dialyzer membranes also had high creatinine and bicarbonate clearances. Bicarbonate loss was balanced by lactate uptake with all dialyzers. It is concluded that CVVHD is an efficient and safe therapy for acute renal failure, capable of maintaining nitrogen balance in patients with protein catabolic rates up to 2 g/kg/day. Urea nitrogen clearance is dependent upon dialysate outflow rate rather than the dialyzer membrane type or dialyzer flow geometry, and may prove to be the modality of choice for therapy of acute renal failure in unstable patients with MOSF.

Acrylic Resins↗
PubMedDate not supplied

Intradialytic parenteral nutrition in chronic hemodialysis patients.

The effects of intradialytic parenteral nutrition (IDPN) were studied in chronic hemodialysis (CHD) patients who had a normalized protein catabolic rate (PCRN) of less than or equal to 0.8 g/kg/day, and KT/V = 0.94 +/- 0.04. Intradialytic parenteral nutrition was administered during thrice weekly CHD for 3-6 months, and consisted of essential and nonessential amino acids (42.5 g), glucose (125 g), and lipid emulsion (50 g). Blood urea nitrogen, creatinine, total protein, albumin, transferrin, pre-albumin, total lymphocyte count, anthropometrics, protein catabolic rate, 3 day historic dietary protein intake, and dietary energy intake (DEI) were measured at baseline, before IDPN, during IDPN, and at completion of IDPN. Six of nine enrolled patients completed the study. Reasons for withdrawal included nausea and hyperglycemia or hypoglycemia. DPI normalized for body weight (DPIN) increased significantly from 0.75 +/- 0.1 to 1.02 +/- 0.18 (p = 0.02). Increases in PCRN (0.57 +/- 0.18 to 0.78 +/- 0.2) and DEI (1495 +/- 266 to 1681 +/- 358) did not reach statistical significance. More aggressive IDPN or a longer study period may be necessary to assess this form of nutritional intervention.

Amino Acids↗