Biomedical subjects

R O Brown

Publications and source records attributed to R O Brown.

84 records · Page 5Linked to original sources

PubMedDate not supplied

Comparison of tolerance and nutritional outcome between a peptide and a standard enteral formula in critically ill, hypoalbuminemic patients.

Dipeptides have been reported to be more efficiently absorbed from the gastrointestinal tract than free amino acids. The objective of this study was to compare prospectively a peptide enteral formula (PEF) with a standard enteral formula (SEF) for tolerance and nutritional outcome in acutely injured, hypoalbuminemic (less than 3.0 g/dL) patients who require enteral nutrition support. The prevalence of diarrhea and elevated gastric residuals was assessed daily. Prealbumin, transferrin, colloid oncotic pressure, Prognostic Nutritional Index, and nitrogen balance were measured on days 0, 5, and 10 of enteral nutrition support. Forty-one patients received 345 days of enteral nutrition support. Prevalences of diarrhea and elevated gastric residuals were similar between groups. Prealbumin increased and the Prognostic Nutritional Index decreased significantly from baseline at day 10 in both groups. Transferrin increased in both groups, but not significantly. Colloid oncotic pressure increased significantly from baseline at days 5 and 10 in the SEF group and day 10 in the PEF group. Nitrogen balance increased significantly from baseline at days 5 and 10 in each group. The only significant difference between groups was for nitrogen balance at day 10, which was higher in the SEF group. We conclude based upon our selected measurements of tolerance and nutritional outcome PEF seems to offer no advantage over SEF in acutely injured, hypoalbuminemic patients.

Adult↗

PubMedDate not supplied

Failure of topical vegetable oils to prevent essential fatty acid deficiency in a critically ill patient receiving long-term parenteral nutrition.

This case report describes the failure of topical vegetable oils containing esters of linoleic acid to prevent essential fatty acid deficiency in a critically ill patient with trauma. A 40-year-old black man injured in a motor vehicle accident developed essential fatty acid deficiency after being maintained on long-term, fat-free parenteral nutrition plus topical vegetable oil application because of the presence of severe hypertriglyceridemia. Biochemical evidence of this deficiency included a decrease in serum linoleic, a-linolenic, and arachidonic acid levels with a corresponding increase in oleic and palmitoleic acid levels. Cutaneous manifestations consistent with this syndrome were also present. After 3 weeks of daily topical treatments with vegetable oils rich in linoleic acid, biochemical abnormalities of deficiency were still evident. Over the following 2 1/2 months, 4% to 22% of the total caloric intake was delivered as intravenous fat in addition to continued topical administration of vegetable oil. Only after supplementation with intravenous fat did the patient demonstrate clinical and biochemical signs of improvement. The results show that cutaneous administration of vegetable oils as the sole source of linoleic acid may be unable to prevent or treat essential fatty acid deficiency in a critically ill surgical patient.

Administration, Cutaneous↗

PubMedDate not supplied

The effect of growth hormone on nutritional markers in enterally fed immobilized trauma patients.

BACKGROUND: Earlier clinical studies have demonstrated improved nitrogen balance in nonstressed patients receiving hypocaloric feedings and growth hormone (GH). This study investigates the effect of GH on nitrogen balance, on serum protein concentrations, and on other indices of nutrition when combined with enteral feeding in immobilized patients after closed-head injury or spinal cord injury. METHODS: Sixteen patients who tolerated enteral feedings and remained nonseptic were randomized to receive either placebo or 0.2 mg/kg recombinant human GH for 7 to 13 days. Nitrogen balances were collected daily, and serum proteins were measured at study entrance and exit. RESULTS: GH treatment resulted in higher GH and insulin-like growth factor-1 concentrations but did not improve nitrogen balance. GH treatment also resulted in increased transferrin and serum albumin levels and total lymphocyte count during the study period. CONCLUSIONS: Adjuvant recombinant human GH has no effect on nitrogen balance in highly stressed, totally immobilized patients after head or spinal cord injury, but it significantly enhances constitutive serum protein concentrations and other indices of nutritional repletion.

Adult↗

PubMedDate not supplied

Early nutrition support modifies immune function in patients sustaining severe head injury.

BACKGROUND: Immunosuppression after severe head injury has been characterized by a depressed CD4 (T-helper/inducer)-CD8 (T-suppressor/cytotoxic) ratio and decreased T-lymphocyte responsiveness. Some investigators propose that this immunocompromized state is the result of an injury-associated hypermetabolic response and inadequate nutrient delivery during the immediate postinjury recovery phase. Previous observations from our institution demonstrated a preserved CD4-CD8 ratio in severe closed-head injury (CHI) patients receiving early parenteral nutrition (PN). It was unclear whether early PN or other aspects of patient care eliminated the characteristic depression in cellular immunity. The purpose of this study was to further investigate the effect of early PN on the immune function of CHI patients. METHODS: Nine patients sustaining severe CHI were prospectively randomized to either early PN (n = 4) at day 1 or delayed PN (n = 5) at day 5. Total nutrient administration was delivered at 2 g of protein/kg per day and 40 nonprotein kcal/kg per day for at least the first 14 days of hospitalization. Analysis for T-lymphocyte expression of CD4 and CD8 cell surface antigens and interleukin-6 was performed on days 1, 3, 7, and 14 of hospitalization. T-lymphocyte activation in response to stimulation by concanavalin A (Con A), phytohemagglutinin (PHA), and pokeweed mitogens (PWM) was also assessed on these days. RESULTS: Significant increases in total CD4 cell counts (2048 +/- 194 to 2809 +/- 129 vs 1728 +/- 347 to 1825 +/- 563, p < .05) and CD4% (42.6 +/- 4.4% to 56.2 +/- 2.6% vs 36.6 +/- 6.6% to 36.6 +/- 11.3%, p < .05) were observed at day 14 in patients receiving early vs delayed PN. An improved lymphocyte response from baseline to day 14 after Con A stimulation was demonstrated in the early PN group (3850 +/- 1596 to 16144 +/- 5024 cpm, p < .05). A significant rise in the CD4-CD8 ratio over baseline to day 14 was also noted in the early PN group (1.43 +/- 0.17 to 2.38 +/- 0.54, p < .05). CONCLUSIONS: The early aggressive nutrition support of CHI patients appears to modify immunologic function by increasing CD4 cells, CD4-CD8 ratios, and T-lymphocyte responsiveness to Con A.

Adolescent↗

PubMedDate not supplied

Hyperkalemia secondary to concurrent pharmacotherapy in a patient receiving home parenteral nutrition.

We report a case of probable combined octreotide- and heparin-induced hyperkalemia. The patient had been receiving home parenteral nutrition, enoxaparin, and octreotide for 10 months. She required very little potassium in her PN solution to maintain serum potassium concentrations in the normal range. The patient reportedly did not receive other medications or have clinical conditions that, to our knowledge, cause hyperkalemia. She maintained normal renal function throughout the hospitalization and did not appear to have any significant acid-base disorders. Practitioners should be aware of the potential for octreotide and heparin to cause hyperkalemia. Regular monitoring of serum potassium concentrations should be done for patients receiving octreotide and heparin to avoid hyperkalemia.

Anticoagulants↗

PubMedDate not supplied

Nutrition and respiratory disease.

Correlations between nutritional status and respiratory function, effects of nutritional substrates on respiration, and optimal nutritional support during respiratory failure are reviewed. Somatic protein depletion is common in patients with either acute respiratory failure or chronic obstructive pulmonary disease. The etiology of the malnutrition includes decreased nutrient intake, increased work of breathing, and increased metabolic rate caused by infections. Excessive administration of glucose or protein can have detrimental effects on respiratory status. Weaning patients from ventilators may be prolonged or even impossible secondary to increased carbon dioxide production in patients receiving high caloric loads of glucose. Excessive protein administration stimulates ventilatory drive and can be detrimental in patients who cannot increase their minute ventilation. Fat is the preferred substrate for energy in selected mechanically ventilated patients requiring total parenteral nutrition because it is oxidized at a lower respiratory quotient than glucose. Measurements of respiratory quotient, oxygen consumption, and carbon dioxide production can be useful in providing optimal nutritional support to the patient with respiratory compromise.

Calorimetry↗

PubMedDate not supplied

A simple technique to reduce ventilator-dependent errors in oxygen consumption measurements.

To evaluate the efficacy of adding a volume reservoir to reduce variability in ventilator-induced fluctuation in inspired oxygen concentration (FiO2) and to reduce oxygen consumption measurement error, we evaluated two ventilators (Puritan-Bennett 7200 and Bear 2) at three inspired oxygen concentrations ranging from 35% to 60%. Continuous sampling of oxygen concentration was conducted for each ventilator. The maximum variability in oxygen concentration was recorded at each minute and oxygen consumption error sensitivity was calculated for both ventilators at three different oxygen concentrations, with and without the use of a baffled 3-L reservoir placed into the inspiratory circuit between the ventilator and test lung. The use of a baffled 3-L reservoir reduced oxygen consumption error sensitivity with the Puritan-Bennett 7200 ventilator at all three oxygen concentrations (p < 0.01). Similar results were found with the Bear 2 ventilator except at the highest FiO2, at which oxygen consumption error sensitivity was not altered. Use of a baffled volume reservoir can significantly reduce ventilator-dependent errors in measuring oxygen consumption via indirect calorimetry. However, when the FiO2 is widely variable, the reservoir is not helpful in reducing error at higher FiO2 concentrations.

Calorimetry, Indirect↗

PubMedDate not supplied

Comparison of specialized and standard enteral formulas in trauma patients.

STUDY OBJECTIVE: To compare selected nutrition and immunologic markers and infection in trauma patients receiving a specialized enteral formula with those receiving standard enteral therapy. DESIGN: Prospective, randomized clinical trial. SETTING: Level 1 trauma center at a county government hospital. PATIENTS: Forty-one consecutive patients with major trauma who required enteral nutrition support. Thirty-seven patients completed the study. Four patients (two in each group) were excluded, as additional operative procedures prevented initiation of enteral feedings within 7 days of injury. INTERVENTIONS: Nineteen patients fed the specialized enteral formula received supplemental arginine, linolenic acid, beta-carotene, and hydrolyzed protein for up to 10 days. Eighteen control patients received standard enteral nutrition. MEASUREMENTS AND MAIN RESULTS: After study entry, patients who received the specialized enteral formula had fewer infections than those receiving standard enteral nutrition (3/19 vs 10/18; p < 0.05). The change in nitrogen balance was significantly better (p < 0.05) from day 1 (-11.8 +/- 1.8 g/day) to day 5 (-5.9 +/- 2.0 g/day) for the group who received the specialized formula compared with the group who received standard enteral nutrition (-7.3 +/- 1.7 g/day to -7.4 +/- 2.8 g/day). Similarly, the change in C-reactive protein serum concentration was significantly better (p < 0.05) from day 1 (18.0 +/- 2.1 mg/dl) to day 5 (11.8 +/- 1.5 mg/dl) in the group who received the specialized formula compared with the group who received standard enteral nutrition (17.6 +/- 1.2 mg/dl to 14.4 +/- 1.7 mg/dl). The CD4:CD8 ratio increased more in the group who received the specialized formula, although this difference did not reach statistical significance. CONCLUSION: Trauma patients who received the specialized enteral formula demonstrated a decreased incidence of infection and increased improvements in nitrogen balance and other indexes of stress. Additional clinical trials demonstrating positive patient outcomes are necessary before these specialized enteral formulas are used as the standard of practice in critically ill patients.

Adolescent↗

PubMedDate not supplied

Octreotide and potassium homeostasis.

Somatostatin infusion causes hyperkalemia in healthy subjects and in some animal models. The purpose of this investigation was to determine what effect octreotide has on potassium homeostasis during serious illness and if there is a dose-response relationship. Sixty-six male Sprague-Dawley rats (185-225 g) were randomized to receive parenteral nutrition (PN) only, PN plus continuous infusion of Escherichia coli lipopolysaccharide (LPS), or PN plus LPS plus octreotide 10, 100, or 1000 micrograms/kg/day for 48 hours. Before randomization all animals received isocaloric, isonitrogenous, isokalemic PN. A 24-hour urine was collected and a blood sample was taken at the end of the study immediately before euthanization. Data were analyzed by ANOVA and Duncan's multiple range test. Nonhemolyzed serum samples from 50 rats were available for study. Serum potassium concentrations were in the normal range for rats and did not differ significantly among the groups: 5.97 +/- 0.86, 5.96 +/- 1.58, 5.78 +/- 1.48, 5.79 +/- 1.67, 5.35 +/- 0.78 mEq/L, respectively. No differences among groups were found for fractional excretion of potassium or serum creatinine concentration. Octreotide administration in escalating dosages does not cause hyperkalemia in endotoxemic rats given intravenous potassium at a constant rate by PN.

Animals↗

PubMedDate not supplied

Impact of a pharmacist-based consult service on nutritional rehabilitation of nonambulatory patients with severe developmental disabilities.

A pharmacist consult service was developed to evaluate the appropriateness of enteral feeding through a permanent ostomy in 24 nonambulatory patients with severe developmental disabilities. Several problems with enteral nutrition were identified. Policies to improve them were instituted, and several educational presentations were made. Pharmacists' actions were implemented, including assessment of energy needs by indirect calorimetry and rearrangement of enteral feeding schedules to achieve optimal nutrition support and pharmacotherapy administration. By the fourth month of the consult service, body weight in these patients increased from 101 +/- 6% of baseline to 109 +/- 7% (p<0.05). Weight continued to increase through the seventh month of the consult service to 116 +/- 12% of baseline (p<0.0001). Measured resting energy expenditure for the group was 889 +/- 170 kcal/day compared with the predicted 1055 +/- 163 kcal/day.

Adolescent↗

PubMedDate not supplied

Effect of sustained endotoxemia on alpha1-adrenergic responsiveness in parenterally fed rats.

We investigated the effect of endotoxemia on alpha1-adrenergic receptor-mediated smooth muscle contraction as measured by mean arterial pressure (MAP) in response to incremental doses of a vasopressor. Twelve male Sprague-Dawley rats were randomized to receive parenteral nutrition alone (PN) or in combination with a continuous infusion of endotoxin (PN-LPS) for 48 hours. Incremental doses of phenylephrine were given and peak MAP response was recorded. The endotoxin group had a decreased rise in MAP with the same dose of phenylephrine compared with the control group (59 +/- 14 and 99 +/- 12 mm Hg, respectively, p<0.001). However, the baseline MAP was higher in the endotoxin group (102 +/- 18 and 71 +/- 7 mm Hg, respectively, p<0.002). The overall maximum effect was the same for both groups (161 +/- 16 and 170 +/- 8 mm Hg, respectively, p=NS). These data indicate that sustained endotoxemia does not result in desensitization of alpha1-adrenergic responsiveness. Other mechanisms are responsible for the ineffectiveness of vasopressors during advanced sepsis.

Adrenergic alpha-Agonists↗

PubMedDate not supplied

Considerations in the use of lipid-based drug products.

The availability and use of intravenous lipid-based drug products is increasing. These products may have increased efficacy, decreased adverse effects, or both when compared with conventional formulations of the same drug. Lipid-based drug products have nutrition support implications when a substantial caloric dose is received during administration of the drug. They also may have unique toxicities and much greater costs than do traditional therapies. The rationale for the use of lipid-based drug products is presented, along with an overview of the proper use of current commercially available lipid-based amphotericin B, propofol, daunorubicin, and doxorubicin products.

Drug Carriers↗