Mononuclear blood cell magnesium content and serum magnesium concentration in critically ill hypomagnesemic patients after replacement therapy.

Magnesium (Mg) deficiency, commonly diagnosed as hypomagnesemia based upon low serum Mg concentrations, is a frequent electrolyte abnormality in critically ill patients. Intravenous replacement therapy is empiric and serum Mg concentrations have traditionally been used as guidelines for measuring efficacy. Recent studies have shown that the Mg content of mononuclear blood cells (MBCs) may provide a better index for Mg status than serum concentrations. The purpose of this study was to evaluate the effects of intravenous Mg replacement therapy on MBC Mg content and serum Mg concentrations in critically ill hypomagnesemic patients. Adult patients admitted to the trauma intensive-care unit (ICU) with serum Mg concentration < or = 0.6 mmol/L (< or = 1.5 mg/dL) were considered for study entry. Patients with severe renal disease (Scr > 133 mumol/L), pregnancy, or those who were seropositive for HIV were excluded. Ten patients with moderate (> 0.4-0.6 mmol/L [> 1.0-1.5 mg/dL]) and severe (< or = 0.4 mmol/L [< or = 1.0 mg/dL]) hypomagnesemia received 0.5 and 0.75 mmol/kg of intravenous MgSO4, respectively, over 24 h. MBC Mg content and serum concentrations of magnesium, phosphorus, calcium, sodium, potassium, blood urea nitrogen, creatinine, glucose, and albumin were measured at baseline (0 h), end of infusion (24 h), 36 h, and 48 h. Data were analyzed using ANOVA with repeated measures and a P value < 0.05 was considered significant. Serum Mg concentrations increased significantly from baseline to 48 h (0.5 +/- 0.1 to 0.8 +/- 0.2 mmol/L, P < 0.001). MBC Mg content did not change significantly within the study period (2.6 +/- 1.0 to 3.0 +/- 1.3 fmol/cell, P > 0.7). The doses of MgSO4 (0.5-0.75 mmol/kg) used in this study increased serum Mg concentrations, but did not result in a statistically significant change of MBC Mg content in this group of trauma ICU patients.

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.

Effect of recombinant human insulin-like growth factor I and early total parenteral nutrition on immune depression following severe head injury.

OBJECTIVE: To determine the effects of insulin-like growth factor I (IGF-I) and aggressive nutrition on CD4/CD8 ratios following head injury. DESIGN: Randomized controlled trial. SETTING: An urban level 1 trauma center. PARTICIPANTS: Head-injured patients with a Glasgow Coma Scale score of 4 to 10 within 6 hours of hospital admission requiring no major extracranial surgery with the exception of isolated lower-extremity fracture fixation. Fourteen patients were recruited and 11 completed the study. INTERVENTIONS: Patients were randomized to a continuous infusion of saline or 0.01 mg/kg per hour of recombinant human (rh) IGF-I. Both groups received parenteral nutrition and rapidly advanced to a total protein intake of 2 g/kg per day and a maximum nonprotein calorie intake of 40 kcal/kg per day. The nonprotein prescription was 1.25 times the metabolic energy expenditure determined by metabolic cart not to exceed a nonprotein calorie intake of 40/kcal. MAIN OUTCOME MEASURES: The CD4/CD8 ratios and serum IGF-I levels on days 1, 7, and 14. RESULTS: Administration of early aggressive nutrition eliminated the depressed CD4/CD8 ratio usually seen after head injury; administration of IGF-I increased the CD4/CD8 ratio while IGF-I levels were elevated. CONCLUSIONS: Infusion of rhIGF-I and aggressive early intravenous nutrition affects the immunologic response of patients with severe head injury.

Specialized nutritional support in respiratory disease.

Nutritional status in patients with respiratory disease is discussed and nutritional support and pharmacotherapy considerations in these patients are reviewed. Undernutrition is common among patients with respiratory disease and can lead to decreased respiratory muscle mass and ventilatory drive. Both overfeeding and underfeeding can adversely affect patient outcome. Specialized nutrition-support regimens for patients with respiratory disease should include carbohydrate doses below the maximal oxidative rates for glucose and fat emulsion as a daily continuous infusion. Early enteral feeding may be beneficial. Respiratory quotient, oxygen consumption, and carbon dioxide production are useful measurements in providing optimal nutrition support. Pharmacotherapeutic measures, such as gastrointestinal-tract decontamination and growth-hormone administration, are being investigated in these patients as adjunctive therapy. Nutrition-support regimens for patients with respiratory disease should be carefully designed and monitored to avoid further compromising respiratory function and to reduce the risk of infection.

Urinary nitrogen constituents in the postsurgical preterm neonate receiving parenteral nutrition.

Minimal information is available defining urinary nitrogen constituents in preterm neonates receiving parenteral nutrition (PN). The study objective was to evaluate 24-hour urine collections for total urinary nitrogen (TUN), urinary urea nitrogen (UUN), and the nitrogen content in creatinine, ammonia, free amino acids, protein, hippuric acid, and uric acid at baseline (days 1 to 2 of PN and days 1 to 3 after surgery) and 7 days later in eight preterm, postsurgical neonates. Calculation of undetermined nitrogen was also completed. Comparisons with historic, normal data were made for each urinary nitrogen constituent. At baseline, PN provided 59 +/- 10 nonprotein kcal/kg.day-1 and 430 +/- 54 mg/kg.day-1. At day 7, PN provided 106 +/- 23 nonprotein kcal/kg.day-1 and 432 +/- 30 mg/kg.day-1. TUN, UUN, and protein nitrogen decreased significantly from baseline at day 7 (p < .05). The percentages of TUN as amino acids, creatinine, and uric acid nitrogen were calculated. Percent amino acid nitrogen (6.0 +/- 2.3% vs 8.4 +/- 1.5%, p < .05), percent creatinine nitrogen (1.6 +/- 0.5% vs 2.9 +/- 0.8%, p < .001) and percent uric acid nitrogen (1.7 +/- 0.9% vs 3.6 +/- 2.1%, p < .05) increased significantly at day 7. The observed urinary free amino acid nitrogen fraction represented a higher percentage of TUN both at baseline and at day 7 when compared with term neonatal reference data, whereas creatinine nitrogen, uric acid nitrogen, and protein nitrogen represented a lower percentage of TUN. However, amino acid and creatinine nitrogen as a percentage of TUN were similar to levels in milk formula-fed preterm infants.(ABSTRACT TRUNCATED AT 250 WORDS)

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.