Biomedical subjects

R J Merritt

Publications and source records attributed to R J Merritt.

45 records · Page 3Linked to original sources

PubMedDate not supplied

In vitro study of in line filtration of medications commonly administered to pediatric cancer patients.

Intravenous administration of drugs commonly used in patients with acute nonlymphocytic leukemia was simulated using a .22 micrometers air-eliminating filter. Drug concentrations were measured pre- and postfiltration using standard pediatric drug doses and concentrations. The percentage of administered dose recovered in the postfilter sample for chemotherapy drugs was adriamycin, 92%; dactinomycin, 87%; cytarabine, 96%; and vincristine, 90%. For antibiotics, the per cent recovery was carbenicillin, 90%; cephalothin, 96%; and gentamicin, 38%. Gentamicin, and perhaps other drugs evaluated, should not be administered through a filter of the type used in this study.

Anti-Bacterial Agents↗

PubMedDate not supplied

Significance of hypoalbuminemia in pediatric oncology patients--malnutrition or infection?

Nutritional status was evaluated on 210 occasions in 90 pediatric oncology inpatients during a 7-month period; 39 had solid tumors and 51 leukemia. Ages ranged from 3 months to 20 yr. Nutritional parameters were defined as normal, "at risk," or "probably malnourished." Fifty-seven and 29% of assessments revealed at least one parameter "at risk" or "probably malnourished," respectively. Prognosis was negatively related to the number of abnormal nutritional parameters. Serum albumin was most frequently abnormal. However, on most occasions, hypoalbuminemia was associated with weight/height, arm muscle area, and triceps skinfold measurements in the normal range. In order to further identify determinants of serum albumin, we analyzed dietary, chemotherapy, and temperature data in 10 prospectively studied leukemia patients, half of whom received parenteral nutrition. In these patients there was little relationship of serum albumin to chemotherapy or dietary intake. In all of these patients, especially those receiving total parenteral nutrition, low serum albumin was highly associated with fever (p less than 0.0005). We concluded that febrile illness is an important determinant of abnormal serum albumin concentrations. In pediatric cancer patients, abnormal serum albumin may more often reflect the acute metabolic response to fever and infection than depletion of body mass.

Adolescent↗

PubMedDate not supplied

Phenobarbital does not prevent total parenteral nutrition-associated cholestasis in noninfected neonates.

Cholestasis associated with total parenteral nutrition (TPN) is a serious complication of this therapy for which there is no known treatment other than beginning enteral feeds. Phenobarbital is commonly used in other cholestatic disease states, but its benefit in this syndrome has not been demonstrated. We conducted a retrospective review of phenobarbital use in neonates receiving concurrent TPN. Thirty-one noninfected neonates were studied. They were without evidence of intrinsic liver disease at the institution of exclusive TPN therapy. For the purposes of this study, TPN-associated cholestasis was defined as a serum bilirubin in excess of 3 mg/dl at postnatal age of 3 weeks or more. Fourteen of the study infants received phenobarbital therapy for neurologic indications. Sixty percent of the phenobarbital-treated infants developed TPN-associated cholestasis, as compared to 33% of the untreated patients. Phenobarbital therapy was not effective in preventing TPN-associated cholestasis.

Cholestasis↗

PubMedDate not supplied

Successful treatment of superior vena cava syndrome with urokinase in an infant.

An 11-month-old infant with a central venous catheter for total parenteral nutrition for short gut syndrome developed head and neck swelling. A thrombus at the catheter tip occluding the superior vena cava was demonstrated roentgenographically. A 48-hr infusion of urokinase (4400 units/kg/hr) was administered for thrombolysis. The thrombus cleared clinically and roentgenographically without adverse effects. There has been no recurrence of the superior vena cava syndrome. Urokinase infusion is an alternative to immediate catheter removal in selected patients.

Catheters, Indwelling↗

PubMedDate not supplied

Partial peritoneal alimentation in an infant.

We provided partial peritoneal alimentation to a 1.69-kg 11-month-old premature infant who had no available central venous access, depleted peripheral venous access, and gastrointestinal dysfunction. A cuffed silastic catheter was surgically inserted into the suprahepatic space. An alimentation solution was continuously infused into the peritoneum for 28 days to supplement peripheral venous and nasogastric alimentation and contributed 42 +/- 15% of total calories daily. Weight gain was achieved, but complications included hypoglycemia, hypophosphatemia, intravascular dehydration, catheter site leakage, ascites, and hydrocele. At autopsy 11 months later, lipid accumulation was present in the upper peritoneum and the hilar regions of the lungs secondary to preexisting lymphatic obstruction. Partial peritoneal alimentation may be feasible when other access routes are inadequate, but lymphatic obstruction is a contraindication to the peritoneal administration of lipid emulsions.

Energy Intake↗

PubMedDate not supplied

Vitamin A sorption to polyvinyl and polyolefin intravenous tubing.

The loss of vitamin A to plastic infusion tubing from a total parenteral nutrition solution was studied using an in vitro infusion system and HPLC quantification of vitamin A. Polyolefin tubing was compared to polyvinyl chloride at varied vitamin A concentration, infusion temperature, and flow rate. Significantly enhanced recovery of vitamin A was found with the polyolefin tubing compared to that of the polyvinyl chloride under all conditions tested. After 24 hours under the varied conditions of the study, vitamin A availability ranged from 47 to 87% with polyolefin and 19 to 74% with polyvinyl chloride. These differences may be expected to result in significantly greater vitamin A delivery from polyolefin compared to polyvinyl chloride tubing to patients treated in neonatal intensive care units.

Infusions, Intravenous↗

PubMedDate not supplied

Serum vitamin A and E concentrations in pediatric total parenteral nutrition patients.

There is uncertainty as to optimal doses of fat soluble vitamins required by pediatric total parenteral nutrition (TPN) patients. We compared serum vitamin A (A) and E (E) concentrations analyzed by HPLC in chronic (greater than 2 weeks) TPN patients aged 1 month to 12 years to values obtained in out-patient surgery patients of the same age. TPN patients received 1500 micrograms of retinol and 2.5 IU of E as alpha-tocopheryl acetate (2.5 ml LyphoMed Multi Vitamin Concentrate). These doses were 214% of the recommended dose of A and 36% for E. Oral intake was minimal in most patients. The results of our study revealed a mean serum A level for TPN patients (N = 29) of 26.0 +/- 15.0 (SD) micrograms/dl vs 25.0 +/- 10.0 (SD) micrograms/dl in controls (N = 52). Mean serum E was 0.63 +/- 0.24 (SD) mg/dl vs 0.89 +/- 0.31 (SD) mg/dl for TPN patients and controls, respectively. There was no consistent trend related to duration of TPN for 23 patients with serial values. Seven (24%) TPN patients had serum A greater than mean + 2 SD of control (p less than 0.01). No values were less than mean - 2 SD. Infants on TPN had a significantly lower mean serum A (22.3 +/- 10.9 micrograms/dl) than TPN patients greater than 1 year of age (34.1 +/- 16.0 micrograms/dl; p less than 0.001). Fifty-two percent of TPN patients vs 26% of control had serum A less than 20 micrograms/dl (p greater than 0.1). For E, one patient had a high value and two patients low values relative to control.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗

PubMedDate not supplied

Vitamin E measurement in patients receiving intravenous lipid emulsions.

Two methods for the determination of plasma vitamin E--high-pressure liquid chromatography and spectrophotofluorometry--were compared on samples from four groups of pediatric patients: children and infants receiving lipid emulsion as part of their parenteral nutrition regimen, neonates receiving parenteral nutrition who were not receiving lipid emulsion at the time of blood sampling, and short admission surgery control subjects. In control subjects and patients not receiving lipid emulsions, both methods yielded similar results for vitamin E as alpha-tocopherol. In contrast, in patients receiving lipid emulsion, the fluorometric method yielded values ranging from 200% to 300% greater than did high-pressure liquid chromatography. The source of the discrepancy is most probably the presence of naturally occurring non-alpha-tocopherol isomers in the lipid products, which add to the fluorescent measurement but are resolved by high-pressure liquid chromatography. This study confirms clinically that fluorescent measurement of vitamin E is no longer the method of choice for monitoring tocopherol status in intensive care nurseries.

Child↗

PubMedDate not supplied

Methemoglobinemia following metoclopramide therapy in an infant.

An infant with persistent vomiting was found to have methemoglobinemia. Review of his history revealed that he had been treated with metoclopramide. No other etiology of the methemoglobinemia was identified. It is concluded that the use of metoclopramide in a sick neonate can cause transient methemoglobinemia. Similar cases reported in the foreign literature are reviewed.

Humans↗