Primary structure and neuronal effects of alpha-bag cell peptide, a second candidate neurotransmitter encoded by a single gene in bag cell neurons of Aplysia

A discharge of impulse activity in a group of neuroendocrine cells, the bag cells, produces several types of prolonged responses in various identified neurons of the abdominal ganglion of Aplysia. Two excitatory responses are almost certainly mediated by egg-laying hormone, but this peptide cannot account for other responses, such as inhibition of left upper quadrant neurons. We report here the isolation from bag cell clusters of three structurally similar peptides, seven, eight, and nine residues long, that are candidate transmitters for mediating bag cell-induced inhibition. They may also serve as autoexcitatory transmitters since the seven-residue peptide produces a slow depolarization of the bag cells similar to that which occurs during bag cell discharge. The amino acid sequence of the largest peptide, termed alpha-bag cell peptide[1-9], is H-Ala-Pro-Arg-Leu-Arg-Phe-Tyr-Ser-Leu-OH. The other two peptides are identical to alpha-BCP[1-9] except that they lack the COOH-terminal Ser-Leu or leucine residues. The three peptides inhibit left upper quadrant neurons at relative potencies of 10:30:1 (seven-, eight-, and nine-residue peptides, respectively). Recent molecular genetic analysis shows that both alpha-BCP[1-9] and egg-laying hormone are encoded by the same bag cell-specific gene. The multiple neuronal effects of bag cells are therefore likely to be mediated by at least two transmitters that are cleaved from a common precursor molecule.

Effect of pentoxifylline on nitrogen balance and 3-methylhistidine excretion in parenterally fed endotoxemic rats

Pentoxifylline interrupts early gene activation for tumor necrosis factor, interleukin-1, and interleukin-6 production and improves survival from experimental sepsis. These effects can alter nitrogen loss during critical illness. To determine the dose-dependent influence of pentoxifylline on nitrogen loss, 44 male Sprague-Dawley rats (220 to 265 g) were randomized to receive parenteral nutrition only (PN), PN plus continuous infusion of Escherichia coli 026:B6 lipopolysaccharide (LPS) at 9 mg x kg(-1) x d(-1), or PN plus LPS plus a continuous infusion of pentoxifylline at either 25 (PEN25) or 100 mg x kg(-1) x d(-1) (PEN100) for 48 h. Before randomization, all animals underwent intravenous cannulation and 40 h of PN adaptation. All animals received isocaloric, isonitrogenous PN (160 kcal x kg(-1) x d(-1) and 1.0 gN x kg(-1) x d(-1)) and were kept nil per os except for water ad libitum. Administration of LPS significantly worsened nitrogen balance for all three groups compared with PN control; however, pentoxifylline only modestly improved nitrogen balance compared with LPS (206 +/- 255, -497 +/- 331, -332 +/- 329, and -310 +/- 383 mg/48hr for the PN, LPS, PEN25, and PEN100 groups, respectively; P < 0.001). Pentoxifylline did not significantly change 3-methylhistidine urinary excretion compared with LPS (573 +/- 180, 705 +/- 156, 780 +/- 326, and 683 +/- 266 microg/48 h for the PN, LPS, PEN25, and PEN100 groups, respectively, P not significant). Pentoxifylline, given in therapeutic doses after an endotoxin challenge, modestly, but not significantly, improved nitrogen balance. Urinary 3-methylhistidine excretion was not influenced by pentoxifylline. A dose-dependent effect by pentoxifylline on these markers was not evident.

A comparison of renal phosphorus regulation in thermally injured and multiple trauma patients receiving specialized nutrition support

To compare phosphorus intake and renal phosphorus regulation between thermally injured patients and multiple trauma patients, 40 consecutive critically ill patients, 20 with thermal injury and 20 with multiple trauma, who required enteral tube feeding were evaluated. Phosphorus intakes were recorded for 14 days from the initiation of tube feeding which was started 1 to 3 days postinjury. Serum for determination of phosphorus concentrations was collected at days 1, 3, 7, and 14 of the study period. A 24-hour urine collection was obtained during the first and second weeks of nutrition support for urinary phosphorus excretion, fractional excretion of phosphorus, renal threshold phosphate concentration, and phosphorus clearance. Average total daily phosphorus intake during the 14-day study for thermally injured patients and multiple trauma patients was 0.99+/-0.26 mmol/kg/d vs 0.58+/-0.21 mmol/kg/d, respectively, p < .001. Serum phosphorus concentration on the third day of observation was significantly lower in the thermally injured group than those with multiple trauma (1.9+/-0.8 mg/dL vs 3.0+/-0.8 mg/dL, p < or = .01). A trend toward hypophosphatemia in the thermally injured group persisted by the seventh day of feeding (2.7+/-1.2 mg/dL vs 3.3+/-0.6 mg/dL, p < or = .04). Differences in urinary phosphorus excretion was not statistically significant between the thermally injured and multiple trauma groups (271+/-213 mg/d vs 171+/-181 mg/d for week 1, and 320+/-289 mg/d vs 258+/-184 mg/d for week 2, respectively). Urinary phosphorus clearance, fractional excretion of phosphorus, or renal threshold phosphate concentrations were also not significantly different between thermally injured and multiple trauma patients. During nutrition support, serum phosphorus concentrations are lower in thermally injured patients compared with multiple trauma patients despite receiving a significantly greater intake of phosphorus. Renal phosphorus regulation does not significantly contribute to the profound hypophosphatemia observed in thermally injured patients when compared with multiple trauma patients during nutrition support.

Oxandrolone in trauma patients

STUDY OBJECTIVE

To determine the effect of oxandrolone administration on nutritional and clinical outcomes after multiple trauma.

DESIGN

Prospective, randomized, double-blind, placebo-controlled study.

SETTING

Level 1 trauma center in a university teaching hospital.

PATIENTS

Sixty-two patients requiring enteral nutrition, 60 of whom completed the study.

INTERVENTION

Patients were randomized to receive either oxandrolone 10 mg or placebo twice/day for a maximum of 28 days.

MEASUREMENTS AND MAIN RESULTS

Total urinary nitrogen, prealbumin, nitrogen balance, total body water, and body cell mass were measured on day 1 of enteral nutrition and then at day 7, day 10, and study exit. Patients were assessed daily for metabolic and infectious complications. The two groups were similar for demographics and dosage of enteral nutrition. Measurement of total urinary nitrogen at study entry showed both groups to be highly catabolic (oxandrolone 17.2 +/- 4.9, placebo 19.1 +/- 10.8 g/day, NS). On days 7 and 10, total urinary nitrogen increased in both groups; however, there was no significant difference between groups. Nitrogen balance was negative throughout the study in each group. Body cell mass decreased slightly in both groups over the study period. Prealbumin serum concentrations increased significantly in both groups at day 10 and study exit compared with study entry. The groups did not differ significantly for length of hospital stay (oxandrolone 30.8 +/- 17.9, placebo 27.0 +/- 25.7 days), length of intensive care unit stay (oxandrolone 17.1 +/- 7.8, placebo 15.5 +/- 9.7 days), and frequency of pneumonia or sepsis (oxandrolone 48, placebo 43 episodes).

CONCLUSION

Oxandrolone 20 mg/day does not have obvious benefit in nutritional and clinical outcomes during the first month after multiple trauma.

Visual motion of missing-fundamental patterns: motion energy versus feature correspondence

Missing-fundamental gratings, generated by subtracting the fundamental Fourier components from square-wave gratings, appear to move backward when presented in quarter-cycle jumps, even though their edges and features all move forward. We used variants of these stimuli to test current models of motion perception. We found that missing-fundamental plaids, constructed from orthogonal missing-fundamental gratings, also appear to move backward. Forward motion was restored to missing-fundamental gratings and plaids by adding back small fractions of the original fundamental. In-phase and antiphase addition of the fundamental had similar effects on the perceived motion, despite having markedly different effects on the features, appearances and zero-crossings of the stimuli. The critical amplitude of fundamental needed to restore forward motion to plaids was the same as that needed to restore forward motion to their isolated component gratings, indicating that the plaids' emergent features, such as edge intersections and 'blobs', made little or no contribution to the perceived direction of motion in these stimuli. In two derivative experiments, missing-fundamental chromatic gratings and plaids, at approximate isoluminance, and missing-fundamental luminance barberpoles, also generated backward perceived motions, and these were also reversed by in-phase or antiphase addition of small amounts of fundamental.

Sequential group trial to determine gastrointestinal site of absorption and systemic exposure of azathioprine

Azathioprine (AZA) is used in the treatment of patients with refractory inflammatory bowel disease; however, its use is limited because of systemic toxicity associated with long-term use. Ileocecal delivery of AZA might be advantageous if local intestinal therapeutic effects could be provided with decreased systemic side effects. Decreased cecal systemic absorption would allow higher dosages of AZA to be administered. A two-phase study was performed to compare the systemic exposure of AZA and 6-mercaptopurine (6-MP) following administration of AZA into the stomach, jejunum, and cecum and to compare the systemic exposure to AZA and 6-MP following administration of three different dosages of AZA into the cecum. In phase I, six healthy male volunteers received three 50 mg sequential doses of AZA via an oral tube directly placed into the stomach, jejunum, and cecum, respectively. In phase II, six healthy male volunteers received three different dosages (50, 300, 600 mg of AZA) into the cecum. Plasma concentrations of AZA and 6-MP at various times were quantified and area under the plasma concentration-time curve (AUC) and mean residence time (MRT) were determined. No significant differences in the AUC of AZA were seen at the different sites. The AUC of 6-MP following administration of AZA into the jejunum (67.0 +/- 30.1 ng x hr/ml) was higher compared to the stomach (39.9 +/- 38.1 ng/hr/ml) and cecum (29.2 +/- 10.9 ng x hr/ml). Jejunal absorption was 68% higher than absorption from the stomach and 129% higher than that of the cecum. Gastric absorption was 27% higher than that of the cecum. Increased dosages given into the cecum resulted in increased AUCs of AZA and 6-MP. The AUCs of AZA following 50, 300, and 600 mg dosages were 16.9 +/- 7.4, 52.3 +/- 67.2, and 132 +/- 151 ng x hr/ml, respectively, and the AUCs of 6-MP were 22.2 +/- 14.9, 63.4 +/- 50.6, and 104 +/- 115 ng x hr/ml, respectively. Systemic exposure to 6-MP is reduced following administration of AZA into the cecum, most likely secondary to reduced absorption of 6-MP from the colon. Higher dosages of AZA presented to the cecum do result in increased systemic absorption, but may still allow more drug to be administered with less toxicity than the same dose received orally.

Sequential single doses of cisapride, erythromycin, and metoclopramide in critically ill patients intolerant to enteral nutrition: a randomized, placebo-controlled, crossover study

OBJECTIVE

To evaluate the comparative efficacy of enteral cisapride, metoclopramide, erythromycin, and placebo for promoting gastric emptying in critically ill patients with intolerance to gastric enteral nutrition (EN).

DESIGN

A randomized, crossover study.

SETTING

Adult medical intensive care unit at a university-affiliated private hospital and trauma intensive care unit at a university teaching hospital.

PATIENTS

Ten adult, critically ill, mechanically ventilated patients not tolerating a fiber-containing EN product defined as a single aspirated gastric residual volume >150 mL or two aspirated gastric residual volumes >120 mL during a 12-hr period.

INTERVENTIONS

Patients received 10 mg of cisapride, 200 mg of erythromycin ethylsuccinate, 10 mg of metoclopramide, and placebo as 20 mL of sterile water every 12 hrs over 48 hrs. Acetaminophen solution (1000 mg) was administered concurrently. Gastric residual volumes were assessed, and plasma acetaminophen concentrations were serially determined by TDx between 0 and 12 hrs to evaluate gastric emptying.

MEASUREMENTS AND MAIN RESULTS

Gastric residual volumes during the study were not significantly different between agents. No differences in area under the concentration vs. time curve or elimination rate constant were identified between agents. Metoclopramide and cisapride had a significantly shorter mean residence time of absorption than erythromycin (6.3+/-4.5 [SEM] mins and 10.9+/-5.8 vs. 30.1+/-4.5 mins, respectively [p<.05]). Metoclopramide (9.7+/-15.3 mins) had a significantly shorter time to peak concentration compared with erythromycin and placebo (60.7+/-8.1 and 50.9+/-13.5 mins, respectively [p<.05]). The time to onset of absorption was significantly shorter for metoclopramide vs. cisapride (5.7+/-4.5 vs. 22.9+/-5.7 mins [p<.05]).

CONCLUSION

In critically ill patients intolerant to EN, single enteral doses of metoclopramide or cisapride are effective for promoting gastric emptying in critically ill patients with gastric motility dysfunction. Additionally, metoclopramide may provide a quicker onset than cisapride.

Measured energy expenditure of tube-fed patients with severe neurodevelopmental disabilities

OBJECTIVE

To determine measured resting energy expenditure (REE) of nonambulatory tube-fed patients with severe neurological neurodevelopmental disabilities.

METHODS

Twenty patients were prospectively studied. Only steady state indirect calorimetry measurements were taken. All measurements were conducted using a canopy system. Nutritional needs were met entirely by enteral feedings via a permanent ostomy.

RESULTS

REE was widely distributed from 16 kcals/kg/day to 39 kcals/kg/day. The mean REE (888+/-176 kcals/day) of the patients was significantly (p<0.01) lower than predicted as estimated by the Harris-Benedict equations (1081+/-155 kcals/day) and World Health Organization equations (1194+/-167 kcals/day). Fat-free mass (FFM) was the best parameter for predicting REE. Two predictive equations were developed that are not significantly biased and more precise (< or =15% error) than conventional predictive formulas.

CONCLUSION

Conventional formulas for estimating energy expenditure are inaccurate and generally overestimate measured energy expenditure of nonambulatory patients with severe developmental disabilities.

Management of the neck in nonmelanocytic cutaneous carcinomas

Cutaneous malignancies are the most common causes of cancer in the United States, and the preponderance occur in the head and neck region. From 0.3% to 13.7% of cutaneous squamous cell carcinomas and from 0.0028% to 0.4% of cutaneous basal cell carcinomas metastasize to the cervical nodes. A description of the head and neck cutaneous lymphatic drainage is presented, followed by recommendations regarding neck dissection modifications appropriate to the primary sites and nodal eschalons involved.

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.

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.

Color appearance depends on the variance of surround colors

BACKGROUND

The perceived color at each point in a visual scene depends on the relationship between light signals from that point, and light signals from surrounding areas of the scene. In the well known phenomenon of simultaneous color contrast, changing the overall brightness or hue of an object's surround induces a complementary shift in the perceived brightness or hue of the object's color. Color contrast is thought to contribute to color constancy with changes in illumination.

RESULTS

We report a new type of simultaneous color contrast, in which changing only the variance (i.e. contrasts and saturations), but not the mean, of colors in a test spot's surround induces a complementary shift in the perceived contrast and saturation of the test spot's color. Objects appear much more vivid and richly colored against low-contrast, gray surrounds than against high-contrast, multicolored surrounds.

CONCLUSIONS

Color appearance depends not just on the mean color of the surround, but also on the distribution of surround colors about the mean. This novel form of simultaneous color contrast is inconsistent with a variety of models of color appearance, including those based on sensitivity regulation at the receptor level, and those in which the effects of complex surrounds on color appearance can be reduced to adaptation to the illuminant or induction from a homogeneous 'equivalent surround'. It tends to normalize the gamut of perceived colors in each visual scene and may also contribute to color constancy under viewing conditions that affect contrast.

The effect of alpha-adrenergic antagonism upon nitrogen loss during endotoxemia

Sixty male Sprague-Dawley rats were randomized to receive parenteral nutrition (PN) only; PN plus continuous infusion of Escherichia coli 026:B6 lipopolysaccharide (PN + LPS) at 6 mg.kg-1.d-1; or PN plus LPS plus a continuous infusion of the alpha-adrenergic antagonist phentolamine (PN + LPS + PHEN) at 5 mg.kg-1.d-1 or 20 mg.kg-1.d-1 for 48 h. All animals received isocaloric, isonitrogenous PN. LPS significantly lowered nitrogen balance (mmol/48 h) from PN control; however, addition of PHEN substantially worsened nitrogen balance compared with LPS (14.2 +/- 3, 2.4 +/- 5.2, -1.6 +/- 4.5, -0.8 +/- 5.4, for the PN, PN + LPS, PN + LPS + PHEN5 and PN + LPS + PHEN20 groups, respectively; P < 0.0001). Urinary 3-methylhistidine/creatinine ratio (3-meH/creat) paralleled the nitrogen balance data (0.30 +/- 0.09, 0.45 +/- 0.12, 0.51 +/- 0.14, 0.60 +/- 0.12, respectively; P < 0.0001). The high-dose PHEN resulted in 82 +/- 9% blockade. To ascertain if any beneficial effect upon body protein loss is achieved during severe stress, 30 rats were given PN + LPS at 12 mg.kg-1.d-1 or PN + LPS12 + PHEN20. These data showed similar changes in nitrogen balance and 3-methylhistidine/creatinine with the use of PHEN during severe endotoxemia. alpha-adrenergic antagonism with PHEN worsens body protein loss as measured by nitrogen balance and 3-methylhistidine/creatinine in PN-fed endotoxemic rats.

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.

Intravenous insulin-like growth factor-I (IGF-I) in moderate-to-severe head injury: a Phase II safety and efficacy trial

The purpose of this study was to determine the effect of insulin-like growth factor-I (IGF-I) on the catabolic state and clinical outcome of head-injured patients. Thirty-three patients between the ages of 18 and 59 years with isolated traumatic head injury and Glasgow Coma Scale (GCS) scores of 4 to 10 were randomized to one of two groups. All patients received standard neurosurgical intensive care plus aggressive nutritional support; the patients in the treatment group also received intravenous therapy with continuous IGF-I (0.01 mg/kg/hour). During the 14-day dosing period, the control patients lost weight, whereas treated patients gained weight despite a significantly higher measured energy expenditure and lower caloric intake (p = 0.02). Daily glucose concentrations and nitrogen outputs were greater in control patients (p = 0.03) throughout the study period. During Week 1, only treated patients achieved positive nitrogen balance. Fifteen of 17 treated and 13 of 16 control patients survived the 1st week. No deaths occurred in patients whose serum IGF-I concentrations were higher than 350 ng/ml. Dichotomized Glasgow Outcome Scale scores for patients with baseline GCS scores of 5 to 7 improved from poor to good for eight of 12 treated patients but for only three of 11 control patients (p = 0.06). Eight of 11 treated patients with serum IGF-I concentrations that were at least 350 ng/ml achieved moderate-to-good outcome scores at 6 months, compared to only one of five patients with lower concentrations (p < 0.05). These findings indicate that pharmacological concentrations of IGF-I may improve clinical outcome and nitrogen utilization in patients with moderate-to-severe head injury.

Intravenous insulin-like growth factor-I (IGF-I) in moderate-to-severe head injury: a phase II safety and efficacy trial

The purpose of this study was to determine the effect of insulin-like growth factor-I (IGF-I) on the catabolic state and clinical outcome of head-injured patients. Thirty-three patients between the ages of 18 and 59 years with isolated traumatic head injury and Glasgow Coma Scale (GCS) scores of 4 to 10 were randomized to one of two groups. All patients received standard neurosurgical intensive care plus aggressive nutritional support; the patients in the treatment group also received intravenous therapy with continuous IGF-I (0.01 mg/kg/hour). During the 14-day dosing period, the control patients lost weight, whereas treated patients gained weight despite a significantly higher measured energy expenditure and lower caloric intake (p = 0.02). Daily glucose concentrations and nitrogen outputs were greater in control patients (p = 0.03) throughout the study period. During Week 1, only treated patients achieved positive nitrogen balance. Fifteen of 17 treated and 13 of 16 control patients survived the 1st week. No deaths occurred in patients whose serum IGF-I concentrations were higher than 350 ng/ml. Dichotomized Glasgow Outcome Scale scores for patients with baseline GCS scores of 5 to 7 improved from poor to good for eight of 12 treated patients but for only three of 11 control patients (p = 0.06). Eight of 11 treated patients with serum IGF-I concentrations that were at least 350 ng/ml achieved moderate-to-good outcome scores at 6 months, compared to only one of five patients with lower concentrations (p < 0.05). These findings indicate that pharmacological concentrations of IGF-I may improve clinical outcome and nitrogen utilization in patients with moderate-to-severe head injury.

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.

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.

Dose-dependent effect of octreotide on nitrogen retention and glucose homeostasis in response to endotoxemia in parenterally fed rats

OBJECTIVE

This study compared the effect of different doses of octreotide on glucose and protein homeostasis in rats receiving concomitant lipopolysaccharide and parenteral nutrition infusions.

METHODS

Sixty-six male Sprague Dawley rats (185 to 220 g) were randomized to receive parenteral nutrition only (PN), PN plus continuous infusion of Escherichia coli 026:B6 lipopolysaccharide at 6 mg/kg/day (LPS), PN plus LPS plus octreotide at 10 micrograms/kg/day (LPS + Oct 10), 100 micrograms/kg/day (LPS + Oct 100), or 1000 micrograms/kg/day (LPS + Oct 1000) for 48 hours. Prior to randomization all animals received isocaloric and isonitrogenous PN (170 kcal/kg/day as glucose and 1.1 g N/kg/day) and were kept nil per os except for water ad libitum. Nitrogen balance, urinary 3-methylhistidine/creatinine ratio, serum glucose concentration, and incidence of glycosuria were compared between groups. Serum urea nitrogen (SUN) changes were incorporated into the cumulative 48 hour nitrogen balance. ANOVA, Duncan's multiple range test, and Fisher's Exact Test were used for statistical analysis.

RESULTS

Nitrogen balance (mg/48 hours) was significantly lower in all four groups receiving LPS +/- Oct when compared to the control group receiving PN alone. SUN (mg/dL) was significantly higher in all four groups receiving LPS +/- Oct when compared to control. There were no statistically significant differences in nitrogen balance or SUN among the four groups receiving LPS +/- Oct. The ratio of urinary 3-methylhistidine/ creatinine was significantly higher in the LPS + Oct 1000 group compared to the PN group (0.77 +/- 0.37 vs. 0.42 +/- 0.24, p < 0.05). Serum glucose concentrations and incidence of glycosuria among the five groups were not significantly different.

CONCLUSIONS

Endotoxin significantly reduces nitrogen balance compared to controls fed PN. Octreotide does not significantly improve nitrogen retention or glucose homeostasis in endotoxemic parenterally fed rats.

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.

A randomized trial of isonitrogenous enteral diets after severe trauma. An immune-enhancing diet reduces septic complications

OBJECTIVE

The authors randomized patients to an enteral diet containing glutamine, arginine, omega-3 fatty acids, and nucleotides or to an isonitrogenous, isocaloric diet to investigate the effect of septic outcome. A third group of patients, without enteral access but eligible by severity of injury, served as unfed controls and were studied prospectively to determine the risk of infection.

SUMMARY BACKGROUND DATA

Laboratory and clinical studies suggest that diets containing specialty nutrients, such as arginine, glutamine, nucleotides, and omega-3 fatty acids, reduce septic complications. Unfortunately, most clinical trials have not compared these diets versus isonitrogenous, isocaloric controls. This prospective, blinded study randomized 35 severely injured patients with an Abdominal Trauma Index > or = 25 or a Injury Severity Score > or = 21 who had early enteral access to an immune-enhancing diet ([IED] Immun-Aid, McGaw, Inc., Irvine, CA; n = 17) or an isonitrogenous, isocaloric diet (Promote [Ross Laboratories, Columbus, OH] and Casec [Mead-Johnson Nutritionals, Evansville, IN]; n = 18) diet. Patients without early enteral access but eligible by severity of injury served as contemporaneous controls (n = 19). Patients were evaluated for septic complications, antibiotic usage, hospital and intensive care unit (ICU) stay, and hospital costs.

RESULTS

Two patients died in the treatment group and were dropped from the study. Significantly fewer major infectious complications (6%) developed in patients randomized to the IED than patients in the isonitrogenous group (41%, p = 0.02) or the control group (58%, p = 0.002). Hospital stay, therapeutic antibiotics, and the development of intra-abdominal abscess was significantly lower in patients receiving the IED than the other two groups. This improved clinical outcome was reflected in reduced hospital costs.

CONCLUSIONS

An IED significantly reduces major infectious complications in severely injured patients compared with those receiving isonitrogenous diet or no early enteral nutrition. An IED is the preferred diet for early enteral feeding after severe blunt and penetrating trauma in patients at risk of subsequent septic complications. Unfed patients have the highest complication rate.

Pharmacologic influence on nutrition support therapy: use of propofol in a patient receiving combined enteral and parenteral nutrition support

Propofol is a lipid-based sedative that provides 1.1 kcal/mL. Because propofol has rapid onset and quick recovery, it is becoming used widely in critical care units. A 15-year-old critically ill pregnant patient received specialized nutrition support concomitantly with propofol infusion for sedation. A serum triglyceride concentration obtained on day 6 of the propofol infusion was 1100 mg/dL with no previous history of hyperlipidemia. Caloric intakes from propofol averaged 1275 kcal/d (range 445 to 2354 kcal/d) over a 5-day period. Infusion of propofol or any other lipid-based drug must be monitored closely when given in conjunction with enteral or parenteral nutrition to avoid the pitfalls of overfeeding and hypertriglyceridemia. Enteral and parenteral formulas must be manipulated to provide optimal nutrient intakes while not overfeeding with fat when using increased amounts of lipid-based drugs.

Treatment of hypophosphatemia in patients receiving specialized nutrition support using a graduated dosing scheme: results from a prospective clinical trial

OBJECTIVE

To determine the safety and efficacy of a graduated dosing scheme of phosphorus replacement therapy in patients with hypophosphatemia receiving specialized nutrition support.

DESIGN

Prospective clinical trial.

SETTING

A 455-bed tertiary care institution, with Level I trauma designation.

PATIENTS

Seventy-eight adult patients, followed and co-managed by a multidisciplinary Nutrition Support Service, with a serum phosphorus concentration of < 3 mg/dL (< 0.97 mmol/L) and no evidence of renal insufficiency, calcium or parathyroid disorders, or obesity.

INTERVENTIONS

Patients were enrolled into one of three categories based on their serum phosphorus concentration: mild hypophosphatemia (2.3 to 3 mg/dL [0.74 to 0.97 mmol/L]), moderate hypophosphatemia (1.6 to 2.2 mg/dL [0.52 to 0.71 mmol/L]), or severe hypophosphatemia (< 1.5 mg/dL [< 0.48 mmol/L]). Each patient received one intravenous phosphorus bolus dose, based on the assigned category of hypophosphatemia, according to a graduated dosing scheme: 0.16 mM/kg (mild), 0.32 mM/kg (moderate), or 0.64 mM/kg (severe). Serum/blood concentrations of phosphorus, calcium, albumin, magnesium, urea nitrogen, and creatinine were measured for three consecutive days.

MEASUREMENTS AND MAIN RESULTS

Sixty-seven patients completed the protocol. There were 31 patients with mild hypophosphatemia, 22 patients with moderate hypophosphatemia, and 14 patients with severe hypophosphatemia. Serum phosphorus concentrations increased significantly (p < .001) in all groups after the phosphorus bolus: 2.6 +/- 0.6 to 3.3 +/- 0.6 mg/dL (0.84 +/- 0.19 to 1.1 +/- 0.19 mmol/L) for the mild group; 1.9 +/- 0.6 to 2.7 +/- 0.6 mg/dL (0.61 +/- 0.19 to 0.87 +/- 0.19 mmol/L) for the moderate group; 1.3 +/- 0.8 to 2.3 +/- 0.8 mg/dL (0.42 +/- 0.26 to 0.74 +/- 0.26 mmol/L) for the severe group. There were no clinically significant changes in serum/blood calcium, albumin, urea nitrogen, or creatinine concentrations and no adverse reactions to the phosphorus regimens throughout the 3-day study period.

CONCLUSION

The graduated dosing scheme of phosphorus replacement therapy is both safe and efficacious in patients receiving specialized nutrition support.

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.

Integrating postgraduate pharmacy training programs into colleges of pharmacy

An important issue facing colleges of pharmacy is the integration of postgraduate clinical training programs into the mainstream of pharmacy education. Colleges of pharmacy have a major role to play in postgraduate clinical training programs to the benefit of the college, resident, and institution. Students must be provided with information about residencies during their first year, and this information must be continually reinforced throughout their academic career. Residency and fellowship programs contribute significantly to the education of pharmacy students. Colleges must take an active role, working in partnership with institutions to enhance postgraduate pharmacy training programs.

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.

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.

Clinical benefits of an immune-enhancing diet for early postinjury enteral feeding

In this multicenter prospective controlled trial, 98 evaluable patients sustaining major torso trauma were randomized to receive early enteral nutrition with a new "immune-enhancing" diet (study: n = 51) or a standard stress enteral formula (control: n = 47). At baseline, both groups had comparable demographics and Injury Severity Scores. After 7 days of feeding, the groups had equivalent increases in serum total protein, albumin, and transferrin concentrations. Patients receiving the "immune-enhancing" diet, however, experienced significantly greater increases in total lymphocyte (p = 0.014), T lymphocyte (p = 0.04), and T-helper (p = 0.004) cell numbers. Additionally, these patients had significantly fewer intraabdominal abscesses (study, 0% vs. control, 11%; p = 0.023) and significantly less multiple organ failure (study, 0% vs. control, 11%; p = 0.023). In conclusion, this multicenter trial suggests this "immune-enhancing" enteral diet offers clinical benefits in stressed surgical patients.

Visceral protein response to enteral versus parenteral nutrition and sepsis in patients with trauma

BACKGROUND

Sepsis and the route of nutrient administration are clearly related to visceral protein levels; however, the mechanisms and amount of influence are not completely defined.

METHODS

Constitutive and acute-phase protein levels were measured on days 1, 4, 7, and 10 in 68 severely injured patients with abdominal trauma indexes of 15 or more randomized to enteral or parenteral feeding. Groups were matched for age, abdominal trauma index, injury severity score, and length of stay.

RESULTS

Significantly higher levels of constitutive proteins and lower levels of acute-phase proteins were found in patients randomized to enteral feeding. Although some "hepatic protein reprioritization" appeared to be caused by nutrient route, this appeared only in the less severely injured patients. A more important factor in visceral protein levels is a reduction in septic morbidity associated with enteral feeding.

CONCLUSIONS

Enteral feeding produces greater increase in constitutive proteins and greater decreases in acute-phase proteins after severe trauma primarily caused by reduced septic morbidity with enteral feeding.

Observations of hypophosphatemia and its management in nutrition support

Severe hypophosphatemia is associated with significant morbidity in hospitalized patients. Specialized nutrition support is an important factor that contributes to the development of this metabolic disorder. Current treatment regimens for hypophosphatemia are empiric and often fail to normalize serum phosphorus concentrations in these patients. Patients who develop hypophosphatemia during the administration of specialized nutrition support exhibit increased phosphorus demands and require aggressive replacement therapy.

Fiber-containing formula and needle catheter jejunostomies: a clinical evaluation

Despite the high frequency of diarrhea, chemically defined diets have traditionally been used with needle catheter jejunostomies, a common form of postpyloric enteral access, to avoid tube occlusion. We reviewed our experience with 57 patients fed a fiber-containing diet to determine the incidence of catheter occlusion and diarrhea. Eight catheters temporarily occluded but were reopened and remained patent for an additional 6.3 +/- 3.1 days for an overall success rate of 91% (52 of 57). The five remaining occluded catheters were removed after 6.2 +/- 1.8 days. Four of the five patients with occluded catheters tolerated gastric feedings, but one required a permanent jejunostomy. Diarrhea occurred in six (10.5%) of the 57 patients given the fiber-containing formula. We concluded that a fiber-containing formula can be administered through needle catheter jejunostomies if the catheter is irrigated daily and if no medications are given via the catheter. A fiber-containing formula may reduce the incidence of diarrhea in jejunostomy-fed patients compared with patients fed chemically defined diets.

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.

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.

Effect of route of nutrition on recovery of hepatic organic anion clearance after fasting

BACKGROUND

Previous work documented a 40% depression of hepatic indocyanine green (ICG) clearance (ClICG) in pigs fasted to 20% weight loss, with return to normal within 12 days of food refeeding. ClICG in pigs is insensitive to changes in hepatic blood flow but very sensitive to changes in hepatic function (HF). Serial ClICG determinations were performed to quantify the effect of route of nutrient delivery on recovery of HF.

METHODS

Fourteen pigs were fasted to 20% weight loss (12.8 days average) with both gastrostomy and intravenous catheters placed in each animal midway through the fast. ClICG was measured before fast, after fast, and after 12 days refeeding through the enteral or parenteral route at 125 kcal/kg/day with isonitrogenous, isocaloric diets containing 9% fat. Urine and stool were analyzed for total nitrogen.

RESULTS

No significant differences appeared between groups in nitrogen output during fasting (4.5 +/- 1.2 gm/kg enteral, 4.6 +/- 1.2 gm/kg parenteral), in nitrogen intake (800 +/- 19 mg/kg/day enteral, 810 +/- 10 mg/kg/day parenteral), or in before or after fast ClICG, but enteral feeding produced more positive nitrogen balance. ClICG improved significantly with enteral but not with parenteral feeding.

CONCLUSIONS

Enteral feeding produces faster nitrogen accrual and reverses the depression of major pathways of bilirubin and organic anion excretion associated with malnutrition. Parenteral feeding failed to improve organic anion clearance despite weight gain.

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.

Enteral versus parenteral feeding. Effects on septic morbidity after blunt and penetrating abdominal trauma

To investigate the importance of route of nutrient administration on septic complications after blunt and penetrating trauma, 98 patients with an abdominal trauma index of at least 15 were randomized to either enteral or parenteral feeding within 24 hours of injury. Septic morbidity was defined as pneumonia, intra-abdominal abscess, empyema, line sepsis, or fasciitis with wound dehiscence. Patients were fed formulas with almost identical amounts of fat, carbohydrate, and protein. Two patients died early in the study. The enteral group sustained significantly fewer pneumonias (11.8% versus total parenteral nutrition 31.%, p less than 0.02), intra-abdominal abscess (1.9% versus total parenteral nutrition 13.3%, p less than 0.04), and line sepsis (1.9% versus total parenteral nutrition 13.3%, p less than 0.04), and sustained significantly fewer infections per patient (p less than 0.03), as well as significantly fewer infections per infected patient (p less than 0.05). Although there were no differences in infection rates in patients with injury severity score less than 20 or abdominal trauma index less than or equal to 24, there were significantly fewer infections in patients with an injury severity score greater than 20 (p less than 0.002) and abdominal trauma index greater than 24 (p less than 0.005). Enteral feeding produced significantly fewer infections in the penetrating group (p less than 0.05) and barely missed the statistical significance in the blunt-injured patients (p = 0.08). In the subpopulation of patients requiring more than 20 units of blood, sustaining an abdominal trauma index greater than 40 or requiring reoperation within 72 hours, there were significantly fewer infections per patient (p = 0.03) and significantly fewer infections per infected patient (p less than 0.01). There is a significantly lower incidence of septic morbidity in patients fed enterally after blunt and penetrating trauma, with most of the significant changes occurring in the more severely injured patients. The authors recommend that the surgeon obtain enteral access at the time of initial celiotomy to assure an opportunity for enteral delivery of nutrients, particularly in the most severely injured patients.

Effect of hypoalbuminemia and parenteral nutrition on free water excretion and electrolyte-free water resorption

OBJECTIVE

To measure the effect of human albumin supplementation during parenteral nutrition on serum albumin concentrations, colloid oncotic pressure, free water clearance, electrolyte-free water resorption, and sodium excretion.

DESIGN

Prospective, randomized, controlled trial.

SETTING

Tertiary care center.

PATIENTS

Thirty adult, hypoalbuminemic patients who required parenteral nutrition.

INTERVENTIONS

Parenteral nutrition (control) or parenteral nutrition plus human albumin 25 g/L as a continuous infusion (treatment) for a 5-day study period.

MEASUREMENTS

On days 1 and 5, serum albumin concentration, colloid oncotic pressure, free water clearance, electrolyte-free water resorption, and sodium excretion were measured.

RESULTS

Serum albumin concentrations increased significantly from day 1 to day 5 in both groups (control: 2.0 +/- 0.1 [mean +/- SEM] vs. 2.3 +/- 0.1 g/dL [20 +/- 1 vs. 23 +/- 1 g/L], p = .02; treatment: 2.2 +/- 0.1 vs. 3.5 +/- 0.2 g/dL [22 +/- 1 vs. 35 +/- 2 g/L], p = .0001). Day 5 serum albumin concentrations were significantly higher in the treatment group compared with control (p = .0001). Colloid oncotic pressure increased significantly from day 1 to day 5 in the treatment group (17.8 +/- 0.8 vs. 25.1 +/- 1.0 mm Hg, p = .0001), and was significantly higher than control at day 5 (p = .0001). No significant differences were found for free water clearance, electrolyte-free water resorption, or sodium excretion within or between groups.

CONCLUSIONS

In hypoalbuminemic patients, human albumin supplementation during parenteral nutrition results in significant increases in serum albumin concentrations and colloid oncotic pressure, but has no apparent effect on free water clearance, electrolyte-free water resorption, or sodium excretion.

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.

The prognostic inflammatory and nutritional index in traumatized patients receiving enteral nutrition support

The prognostic inflammatory and nutritional index (PINI) is a clinical assessment tool which aggregates serum C-reactive protein (CRP), alpha 1-acid glycoprotein (AAG), prealbumin (PA), and albumin (ALB) concentrations into a single score. This study was conducted to characterize the index and its determinants over time in 15 critically ill trauma patients receiving enteral nutritional support (ENS). Patients received 1.4 g of protein/kg/day and 32 kcal/kg/day for at least 7 days using a nutritionally complete formula supplemented with whey protein. The PINI was calculated at baseline and on days 4, 7, 10, 14, 21, and 28. The PINI decreased significantly from baseline (186 +/- 202) to day 4 (116 +/- 86) and reached a nadir at day 14 (27 +/- 40). Serum CRP concentrations decreased significantly during the study period, while PA and ALB concentrations increased significantly. There was no change in the AAG concentration. Nitrogen balance increased significantly during the study period. The PINI was positively correlated with CRP concentration (r = 0.72, p = 0.0001) and negatively correlated with PA concentration (r = 0.56, p = 0.0004 and nitrogen balance (r = -0.51, p = 0.0018). The PINI decreased significantly during ENS of critically ill trauma patients, influenced primarily by a decrease in CRP concentration. Further studies are needed to characterize the PINI's performance as a prognostic tool.

Toxicities of parenteral nutrition in the critically ill patient

Critically ill patients have unique nutritional substrate requirements. Although important advances have been made in understanding these requirements in the face of pathophysiologic and biochemical alterations induced by stress or trauma, nutrition-associated toxicities still occur. The importance of these toxicities to the critically ill patients cannot be over-stated. Many of these toxicities can be avoided by conservative use of selected nutrition substrates in specific subsets of the critically ill population. Practitioners must continue to anticipate and recognize parenteral nutrition-associated toxicities, however, as well as delineate any toxicity from the progression or exacerbation of disease.

Pharmacist interventions improve fluid balance in fluid-restricted patients requiring parenteral nutrition

Many intensive care unit (ICU) patients require parenteral nutrition (PN) and fluid restriction, making delivery of adequate nutrition difficult. We studied the effects of pharmacist interventions on fluid balance in fluid-restricted ICU patients requiring PN. Twenty patients were randomized to the treatment group (dextrose 70% injection [D70W] plus 15% amino acids for PN, 25-mL piggybacks, selected drugs added to the PN solution) or the control group (D70W plus 10% amino acids, 50- or 100-mL piggybacks). Each group contained 10 patients and they were not significantly different for age, gender, weight, hospital days, and serum albumin concentration. The duration (9.3 +/- 1.2 vs. 9.7 +/- 2.4 d) and doses of PN (29 +/- 6.8 vs. 28.7 +/- 6.9 kcal/kg/d; 1.1 +/- 0.3 vs. 1.1 +/- 0.4 g/kg/d protein) were similar between treatment and control groups. Mean fluid intake (3112 +/- 1146 vs. 3498 +/- 1111 mL/d), fluid balance (146 +/- 1581 vs. 708 +/- 1402 mL/d), and cumulative fluid balance (1358 vs. 6867 mL) were all significantly lower in the treatment group. Mean fluid output was similar between the two groups. Pharmacist interventions can significantly decrease intake and result in a better fluid balance in fluid-restricted ICU patients who require PN.

Comparison of modified amino acids and standard amino acids in parenteral nutrition support of thermally injured patients

Twenty thermally injured patients who could not tolerate enteral nutrition support were randomized to receive parenteral nutrition (PN) with either modified amino acids (MAA) or standard amino acids (SAA). There was no significant difference between groups for age, sex, weight, percent BSA area burn, percent third-degree burn, or operative procedures. N balance (NB) was measured and serum was harvested for circulating fibronectin (Fn), somatomedin-C/insulin-like growth Factor I (Sm-C), prealbumin (PA), and retinol-binding protein (RBP) analysis on days 1, 4, 7, 14, 21, and 28 of PN. The patient groups received similar doses of PN for a similar number of days. Fn did not change significantly from baseline in either group and there was no significant difference between groups. Sm-C increased significantly from baseline at day 7 in the SAA group and in both groups on day 14, but there was no significant difference between groups. PA and RBP increased significantly from baseline on day 7 in the MAA group and in both groups on days 14, 21, and 28. RBP was significantly higher in the MAA group only on day 21, and there was no significant difference between groups for PA. NB increased significantly from baseline for all study days; however, there was no significant difference between groups. PN in thermally injured patients significantly improves NB and increases visceral protein concentrations. However, there appears to be no difference between PN with MAA or SAA.

Use of selected visceral protein measurements in the comparison of branched-chain amino acids with standard amino acids in parenteral nutrition support of injured patients

Twenty injured patients in the intensive care unit were randomized to receive parenteral nutrition with either 21% (STD) or 46% (HBC) branched-chain amino acids to compare the response of nitrogen balance (NB), somatomedin-C/insulin-like growth factor I (SMC), circulating fibronectin (FBN), and prealbumin (PA). NB was measured and serum collected for SMC, FBN, and PA on days 1, 4, 7, 14, and 21 of nutritional intervention. The treatment groups did not differ significantly for age, weight, injury severity score, trauma score, Apache II score, acute-phase protein concentrations, or type of injury. Comparison of baseline measurements revealed no significant differences in SMC, FBN, or PA. Both groups received similar doses of nonprotein energy and nitrogen. Baseline urea nitrogen excretion was slightly higher in the STD group (216 +/- 55 vs 268 +/- 54 mg/kg/day p = 0.049). Although NB was significantly improved over baseline during subsequent study days, there were no differences between groups after the day-1 measurement. SMC increased significantly from baseline on day 4 in the STD group, on day 7 in the HBC group, and on days 14 and 21 in both groups. There was no significant difference in SMC concentrations between groups on any day. Each group demonstrated a significant increase in PA from baseline on days 7, 14, and 21; however, no difference was seen when groups were compared. FBN increased significantly from baseline on day 14 in the HBC group and on days 7 and 14 in the STD group. FBN measurements were significantly different between groups on day 14 (STD, 179 +/- 71 vs HBC, 229 +/- 59 micrograms/ml; p less than 0.05). NB, PA, SMC, and FBN improve significantly during parenteral nutrition of traumatized patients. With the measured variables, there appears to be no significant difference between STD or HBC amino acids when used as part of parenteral nutrition in injured patients.