Loss of upper respiratory tract immunity with parenteral feeding

OBJECTIVE

The authors examine the effect of route and type of nutrition on an established upper respiratory tract immunity and investigate potential mechanisms for increased pneumonia rates in critically injured patients fed parenterally.

SUMMARY BACKGROUND DATA

The primary immunologic defense against many mucosal infections is IgA. Prior work shows that mice fed total parenteral nutrition (TPN) solutions either intravenously or intragastrically had small intestinal gut-associated lymphoid tissue (GALT) atrophy along with decreased intestinal IgA compared with animals fed complex enteral diets. The small intestine is postulated to be the origin of most mucosal immunity, both intraintestinal and extraintestinal. The impact of diets affecting GALT, small intestine IgA, and upper respiratory tract immunity is studied.

METHODS

Male Institute of Cancer Research mice underwent intranasal inoculation with a mouse-specific influenza virus to establish immunity. Three weeks later, the mice were randomized to chow, intragastric Nutren (Clintec, Chicago, IL), intravenous TPN, or intragastric TPN. After 5 days of feeding, mice were challenged with intranasal virus and killed at 40 hours to determine viral shedding from the upper respiratory tract.

RESULTS

Despite similar body weights, there was significant atrophy in the Peyer's patch cells from animals fed the TPN solution intravenously or intragastrically. There was no viral shedding in any animal fed via the gastrointestinal tract, whereas 5 of 10 animals fed intravenous TPN had continued viral shedding.

CONCLUSIONS

The IgA-dependent upper respiratory tract immunity was preserved with enteral feeding but not with intravenous feeding. Upper respiratory tract immunity is not dependent on intestinal GALT mass but is influenced by route of nutrition. The underlying mechanisms may explain the higher pneumonia rate in critically injured patients fed parenterally.

Blunt carotid injury. Importance of early diagnosis and anticoagulant therapy

OBJECTIVE

The incidence, associated injury pattern, diagnostic factors, risk for adverse outcome, and efficacy of anticoagulant therapy in the setting of blunt and carotid injury (BCI) were evaluated.

SUMMARY BACKGROUND DATA

Blunt carotid injury is considered uncommon. The authors believe that it is underdiagnosed. Outcome is thought to be compromised by diagnostic delay. If delay in diagnosis is important, it is implied that therapy is effective. Although anticoagulation is the most frequently used therapy, efficacy has not been proven.

METHODS

Patients with BCI were identified from the registry of a level I trauma center during an 11-year period (ending September 1995). Neurologic examinations and outcomes, brain computed tomography (CT) results, angiographic findings, risk factors, and heparin therapy were evaluated.

RESULTS

Sixty-seven patients with 87 BCIs were treated. Thirty-four percent were diagnosed by incompatible neurologic and CT findings, 43% by new onset of neurologic deficits, and 23% by physical examination (neck injury, Horner's syndrome). There were 54 intimal dissections, 11 pseudoaneurysms, 17 thromboses, 4 carotid cavernous fistulas, and 1 transected internal carotid artery. Thirty-nine patients had follow-up angiograms. Mortality rate was 31%. Of 46 survivors, 63% had good neurologic outcomes, 17% moderate, and 20% bad. Logistic regression analysis demonstrated heparin therapy to be associated independently with survival (p < 0.02) and improvement in neurologic outcome (p < 0.01).

CONCLUSIONS

Blunt carotid injury is more common than appreciated, seen in 0.67% of patients admitted after motor vehicle accidents. Therapy with heparin is highly efficacious, significantly reducing neurologic morbidity and mortality. Heparin therapy, when instituted before onset of symptoms, ameliorates neurologic deterioration. Liberal screening, leading to earlier diagnosis, would improve outcome.

A prospective analysis of transesophageal echocardiography in the diagnosis of traumatic disruption of the aorta

OBJECTIVE

Recently, transesophageal echocardiography (TEE) has been proposed as the standard for the diagnosis of traumatic disruption of the aorta (TDA), replacing aortography. The purpose of this study was to evaluate the accuracy and practicality of TEE in the diagnosis of TDA.

DESIGN

Prospective clinical trial.

MATERIALS AND METHODS

Patients with blunt trauma admitted with a suspected diagnosis of TDA were evaluated with TEE and aortography.

MEASUREMENTS AND MAIN RESULTS

Thirty-four patients were evaluated with TEE and aortography. TEE was unsuccessful in five patients (15%). Of the remaining 29 patients, TEE results were true-positive in four and true-negative in 20. TEE results were false-positive in two patients, and three injuries were missed (two were proximal to the left subclavian artery, and one was a localized aortic disruption). Sensitivity and specificity of TEE were 57% and 91%, respectively, compared with aortography, for which sensitivity was 89% and specificity was 100%.

CONCLUSION

Although the use of TEE in the diagnosis of TDA has several advantages, it is not more accurate than aortography. TEE should not replace aortography as the standard for the diagnosis of TDA.

Using bronchoalveolar lavage to distinguish nosocomial pneumonia from systemic inflammatory response syndrome: a prospective analysis

OBJECTIVE

Ventilator-associated pneumonia (PN) is difficult to distinguish from trauma-induced systemic inflammatory response syndrome (SIRS), especially in patients with multiple injuries. Previous work using bronchoscopy and quantitative cultures demonstrated significant bacterial growth in about one-third of patients with clinical evidence of PN. In this prospective study, antibiotic therapy for PN was based solely on quantitative bronchoalveolar lavage (BAL) cultures.

METHODS

Mechanically ventilated trauma patients underwent bronchoscopy with BAL when they developed clinical evidence of PN: fever (temperature > 100.5 degrees F), white blood cells > 10,000 or > 10% immature forms, purulent sputum, and new or changing infiltrate on chest roentgenogram. Patients with other infections or those receiving antibiotics for any other reason were excluded. Empiric antibiotic therapy for PN was started at the time of BAL. If the quantitative cultures revealed > or = 10(5) colony-forming units (CFU)/mL, that patient was defined as having PN and was treated. If the cultures revealed < 10(5) CFU/mL, that patient was defined as having SIRS, and empiric therapy was stopped.

RESULTS

Forty-three patients (88% blunt, 12% penetrating) underwent bronchoscopy with BAL 55 times. Mean age was 40 and Injury Severity Score was 25. Twenty patients had > or = 10(5) CFU/mL (47%) and 23 had < 10(5) CFU/mL (53%). There were no differences in age, Injury Severity Score, temperature, white blood cell count, or ventilator days before BAL between groups. Sixty-five percent of those with SIRS improved after empiric therapy was stopped (average 3.3 days), and 35% underwent repeat BAL. Three patients with the initial diagnosis of SIRS developed PN (13% of SIRS). Mortality for PN was 15%, compared with 17% for SIRS; no deaths were related to antibiotic therapy.

CONCLUSIONS

SIRS, which can mimic PN, is common in trauma patients. These entities can be distinguished by bronchoscopy with BAL. Basing antibiotic therapy solely on quantitative BAL cultures is efficacious in trauma patients.

Bombesin affects mucosal immunity and gut-associated lymphoid tissue in intravenously fed mice

BACKGROUND

Our prior studies show that intravenous (IV) total parenteral nutrition (TPN) produces atrophy of the small intestine-related gut-associated lymphoid tissue and significant decreases in intestinal IgA levels, the major system of mucosal immunity. Others have noted increased small intestinal permeability, bacterial adherence and translocation, and decreased IgA levels in TPN-fed animals. Bombesin, a neuropeptide, may play a regulatory role in mucosal immunity. It is not clear whether bombesin attenuates the TPN-associated gut-associated lymphoid tissue atrophy.

OBJECTIVE

To examine the effect of bombesin on gut-associated lymphoid tissue integrity and function during IV TPN feeding.

DESIGN

Randomized animal study.

SETTING

A university laboratory.

MATERIALS AND METHODS

Male ICR mice weighing 25 to 30 g were randomized to chow plus IV saline solution (n = 12), IV TPN (n = 12), or IV TPN plus bombesin (15 micrograms/kg, administered intramuscularly three times a day) (n = 12). Animals were killed after 5 days of receiving the experimental diet. Total small intestinal IgA level was quantified by enzyme-linked immunosorbent assay. Lymphocytes were isolated from Peyer's patches, intraepithelial spaces, and lamina propria and were stained with specific antibodies for B and T cells and for T-cell expression of CD4 and CD8 by flow cytometric analysis. Data were analyzed by analysis of variance.

RESULTS

Bombesin prevented the IV TPN decreases in (1) total cell yield and B-cell yield from the Peyer's patches, intraepithelial spaces, and lamina propria; (2) T-cell yield in the intraepithelial spaces and lamina propria; and (3) small intestinal IgA levels. Bombesin also reversed IV TPN decreases in CD4+ and CD8+ T cells in the intraepithelial spaces and Peyer's patches and prevented the decrease in the CD4/CD8 ratio in the lamina propria.

CONCLUSION

Bombesin prevents the TPN-associated atrophy and dysfunction of gut-associated lymphoid tissue, supporting the concept of close neuroimmunologic interaction.

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.

Management of blunt splenic trauma: computed tomographic contrast blush predicts failure of nonoperative management

Nonoperative management of blunt splenic trauma is widely accepted; however, reported failure rates have ranged as high as 40%. There are few factors available to identify failures reliably. To characterize failures of nonoperative management better, we retrospectively reviewed 309 blunt splenic injuries treated at our level I trauma center over a 5-year period. Eighty-nine patients were initially managed nonoperatively (29%), and 12 patients failed this approach (13%). Upon review of the initial computed tomography scans, a hyperdense collection of contrast media in the splenic parenchyma, or "contrast blush," was noted in 8 of 12 (67%) patients who failed and in 5 of 77 (6%) of those who were successfully managed nonoperatively (p < 0.0001). These data suggest that the presence of a contrast blush is an important consideration when deciding the method for management of the splenic injury. If these results are confirmed in a prospective fashion, the failure rate of nonoperative management of blunt splenic trauma could be reduced by identification of the contrast blush.

Prognostic factors after acute subdural hematoma

Factors that have been shown to affect outcome after acute subdural hematoma (ASDH) include age, Injury Severity Score (ISS), intracranial pressure (ICP), direct admission to a trauma center, presence of subarachnoid hemorrhage, score on the Glasgow Coma Scale (GCS), and timing of operation. However, these data come from selected patient populations (e.g., operated, comatose, or minimally symptomatic patients, etc.). In an effort to evaluate factors that predict outcome for the entire spectrum of ASDH patients, we evaluated 211 patients with ASDH and GCS scores of 3 to 15. One hundred twenty-eight patients (61%) were managed nonoperatively (Nonop), whereas 83 (39%) were managed with craniotomy [operatively (Op)]. Op patients had more severe brain injuries, as evidenced by their lower GCS scores (Op 7.8 vs. Nonop 10.7, p = 0.0001), higher incidence of large ASDH with midline shift (Op 61% large ASDH, 83% midline shift vs. Nonop 16% large ASDH, 30% midline shift, p = 0.001 for each comparison), and higher incidence of basilar cistern effacement (Op 61% vs. Nonop 21%, p = 0.001). Thirty-five percent of the Op patients had their hematoma evacuated within 4 hours (early), whereas 65% did not (delayed). Early Op patients had a significantly lower incidence of functional survival (early = 24% vs. delayed = 51%, p = 0.02). The early patients seem to have had more significant head injuries, as evidenced by their lower GCS scores (early = 7.0 vs. delayed = 8.4), higher incidence of associated intracranial injuries (early = 1.14 vs. delayed = 0.85), and higher incidence of cistern effacement (early = 76% vs. delayed = 53%, p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of parenteral and enteral nutrition on gut-associated lymphoid tissue

Changes in mucosal defense have been implicated as important factors affecting infections complications in critically ill patients. To study the effects of nutrient administration on gut-associated lymphatic tissue (GALT), ICR mice were randomized to receive chow plus intravenous saline, intravenous feeding of a total parenteral nutrition (TPN) solution, or enteral feeding of the same TPN solution. In a second series of experiments, a more complex enteral diet (Nutren) was compared with chow feeding and enteral TPN. After 5 days of feeding with experimental diets, lymphocytes were harvested from the mesenteric lymph nodes (MLNs), Peyer's patches (PPs), lamina propria (LP) cells, and intraepithelial (IE) spaces of the small intestine to determine cell yields and phenotypes. Small intestinal washings, gallbladder contents, and sera were collected and analyzed for immunoglobulin A (IgA) levels. In both series of experiments, there were no significant changes within the MLNs. There were significant decreases in total cell yields from the PPs, IE spaces, and LP in animals fed with TPN solution, either enterally or parenterally, as compared with chow-fed mice. Total T cells were decreased in both TPN-fed groups in the PPs and LP, whereas total B cells were decreased in the PP, IE, and LP populations. Total cell numbers remained normal in the Nutrenfed group, except for a decrease in LP T cells. CD4+ LP cells decreased significantly with a reduction in the CD4/CD8 ratio in mice fed TPN solution either intravenously or enterally, whereas IgA recovery from small intestinal washings was significantly decreased in the same groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Nonoperative management of blunt hepatic trauma is the treatment of choice for hemodynamically stable patients. Results of a prospective trial

BACKGROUND

A number of retrospective studies recently have been published concerning nonoperative management of minor liver injuries, with cumulative success rates greater than 95%. However, no prospective analysis that involves a large number of higher grade injuries has been reported. The current study was conducted to evaluate the safety of nonoperative management of blunt hepatic trauma in hemodynamically stable patients regardless of injury severity.

METHODS

Over a 22-month period, patients with blunt hepatic injury were evaluated prospectively. Unstable patients underwent laparotomies, and stable patients had abdominal computed tomography (CT) scans. Those with nonhepatic operative indications underwent exploration, and the remainder were managed nonoperatively in the trauma intensive care unit. This group was compared with a hemodynamically matched operated cohort of blunt hepatic trauma patients (control subjects) who had been prospectively analyzed.

RESULTS

One hundred thirty-six patients had blunt hepatic trauma. Twenty-four (18%) underwent emergent exploration. Of the remaining 112 patients, 12 (11%) failed observation and underwent celiotomy--5 were liver-related failures (5%) and 7 were nonliver related (6%). Liver related failure rates for CT grades I through V were 20%, 3%, 3%, 0%, and 12%, respectively, and rates according to hemoperitoneum were 2% for minimal, 6% for moderate, and 7% for large. The remaining 100 patients were successfully treated without operation--30% had minor injuries (grades I-II) and 70% had major (grades III-V) injuries. There were no differences in admission characteristics between nonoperative success or failures, except admission systolic blood pressure (127 vs. 104; p < 0.04). Comparing the nonoperative group to the control group, there were no differences in admission hemodynamics or hospital length of stay, but nonoperative patients had significantly fewer blood transfusions (1.9 vs. 4.0 units; p < 0.02) and fewer abdominal complications (3% vs. 11%; p < 0.04).

CONCLUSIONS

Nonoperative management is safe for hemodynamically stable patients with blunt hepatic injury, regardless of injury severity. There are fewer abdominal complications and less transfusions when compared with a matched cohort of operated patients. Based on admission characteristics or CT scan, it is not possible to predict failures; therefore, intensive care unit monitoring is necessary.

Increased intestinal permeability following blunt and penetrating trauma

OBJECTIVES

To determine changes in the absorption of lactulose and mannitol in patients undergoing laparotomy following blunt or penetrating trauma and to correlate any changes in permeability with the severity of injury.

DESIGN

Nonrandomized study within patient control.

PATIENTS

Consecutive patients admitted to the trauma unit following blunt or penetrating trauma with intra-abdominal injuries warranting emergent celiotomy and jejunal access.

INTERVENTIONS

Intestinal permeability was measured in 18 patients within 48 hrs post-trauma by the bolus infusion into the jejunum of nonmetabolized probe molecules, lactulose (molecular weight of 342) and mannitol (molecular weight of 182). Because several patients did not tolerate the bolus infusion, a 3-hr continuous infusion of the probe molecules was used in the last eight patients entered into the study. Intestinal permeability was reassessed before discharge or on days 10 to 12.

MEASUREMENTS AND MAIN RESULTS

There was a decrease in urinary lactulose excretion and the lactulose/mannitol ratio between the initial posttrauma measurement and the follow-up permeability measurement using both the bolus infusion (lactulose: initial 0.13 +/- 0.032 vs. follow-up 0.047 +/- 0.012 mmol/6 hrs, p < or = .05; lactulose/mannitol: initial 0.067 +/- 0.012 vs. follow-up 0.044 +/- 0.012, p = .11) and the continuous infusion (lactulose: initial 0.044 +/- 0.013 vs. follow-up 0.014 +/- 0.002 mmol/2 hrs, p < or = .05; lactulose/mannitol: initial 0.055 +/- 0.020 vs. follow-up 0.015 +/- 0.007, p < or = .05). Urine excretion of mannitol was not significantly different between posttrauma and follow-up measurements of intestinal permeability, regardless of the technique used to infuse the lactulose and mannitol. Although the decrease in lactulose and the lactulose/mannitol ratio was significant, only one third of the patients had dramatically increased permeability at the initial measure. Abdominal Trauma Index and Injury Severity Score did not correlate with urinary lactulose excretion or the lactulose/mannitol ratio. Patient tolerance of jejunal administration of lactulose and mannitol was better, using a 3-hr continuous infusion of a dilute solution compared with bolus infusion.

CONCLUSIONS

Intestinal permeability is increased in the first 48 hrs posttrauma and decreases with recovery. Although one third of the patients had highly increased lactulose/mannitol ratios posttrauma, severity of injury, assessed by common scoring techniques, did not correlate with the degree of permeability. Tolerance to jejunal administration of lactulose and mannitol is improved with a slow infusion of a dilute solution over a 3-hr period compared with bolus administration.

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.

Fasting-induced reduction of intestinal reperfusion injury

BACKGROUND

Fasting is associated with significant structural, functional, and metabolic alterations in the intestinal mucosa. Before abdominal surgery, patients are usually fasted the night before surgery or for a longer period of time if chronic illness is present. The splanchnic organs may experience varying degrees of ischemia/reperfusion as blood vessels are occluded during the various manipulations.

METHODS

To study whether fasting alters intestinal reperfusion injury, rats were fasted for 0 to 2 days, and the mesenteric artery was occluded for 30 minutes and then reperfused for 1 hour. Mucosal atrophy was quantitated by measuring jejunal villus height and crypt depth, and mucosal injury was quantitated by measuring jejunal villus width to villus height and mucosal integrity. To determine whether any effect of fasting on reperfusion injury was due to the absence of luminal nutrients or to a systemic nutrient deficiency, rats were fed parenterally for 7 days before ischemia/reperfusion.

RESULTS

A 1-day fast produced significant mucosal atrophy. Reperfusion in the 0-day and 1-day fasted animals produced mucosal injury and additional mucosal atrophy. After a 2-day fast, there was no mucosal injury or mucosal atrophy other than that produced by fasting alone. Parenteral feeding before ischemia/reperfusion did not prevent ischemia/reperfusion induced mucosal atrophy and injury.

CONCLUSIONS

The protective effect of a 2-day fast before intestinal ischemia/reperfusion cannot be attributed to the physical and chemical absence of food within the intestinal lumen.

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.

Effect of route of feeding on the incidence of septic complications in critically ill patients

The increased risk of septic complications accompanying severe illness and injury is compounded by the presence of malnutrition. Total parenteral nutrition (TPN) has been used extensively to prevent or rectify this problem. Although enteral nutrition is frequently more difficult to administer, a growing body of laboratory and clinical research shows a significant reduction in the incidence of secondary infection with its use. The mechanism proposed is that the enteral route helps maintain the gut barrier, decreasing passage of bacteria and other toxins. Translocation of these products has been implicated as a cause of nosocomial infection and organ failure. Therefore, when possible, the use of the enteral route of nutrition should be part of the overall approach to the care of the critically ill or injured patient.

Analysis of charges associated with diagnosis of nosocomial pneumonia: can routine bronchoscopy be justified?

Many ventilated trauma patients thought to have nosocomial pneumonia have pulmonary contusion or systemic inflammatory response syndrome with tracheobronchial colonization. Fiberoptic bronchoscopy with quantitative culture techniques of protected specimen brush (PSB; threshold 10(3) cfu/mL) or bronchoalveolar lavage (BAL; threshold 10(5) cfu/mL) can potentially eliminate the false positive cultures of the upper airway seen with routine sputum aspirates (RS). However, bronchoscopy is expensive, and routine use may not be cost effective. This prospective study evaluated the patient charges associated with bronchoscopy and quantitative cultures compared with RS for the diagnosis of nosocomial pneumonia. Specimens were obtained by RS, PSB, and BAL from the lower airway in 107 trauma patients (136 sets of triplicate cultures). All patients had clinical evidence suggestive of pneumonia (fever, leukocytosis, purulent sputum, abnormal roentgenographic findings). Typical oral flora were considered contaminants; no gram-negative specimens were excluded. Mean age was 40 years and mean ISS was 29. Seventy-eight percent had blunt injuries, 22% penetrating, and 42% had chest injuries. The incidence of nosocomial pneumonia according to each method was: RS-73%; PSB-34%; BAL-25%. Considering all charges involved (bronchoscopy, equipment, microbiologic analysis, and antibiotics), and based on a 14-day course of ceftazidime and vancomycin, the charges for PSB were 58% of RS, and charges for BAL were 43% of RS. We conclude that the charges associated with bronchoscopy are high, but can be offset by antibiotic savings. Side effects of unnecessary antibiotic therapy would be avoided. Further study is needed to determine the efficacy of PSB or BAL in trauma patients.

Metabolic response to critical illness and injury

The metabolic response to critical illness and injury increases the metabolic rate and increases mobilization of amino acids from the peripheral tissues. This is done through a neuroendocrine response with elevated levels of catecholamines, glucocorticoids, inflammatory cytokines, and other products of inflammation. Control of the injury, restoration of hemodynamic stability, and early nutrition can minimize the drain on the lean body mass and improve the chance of survival. In this article, the authors summarize the metabolic response to stress and injury.

Clinical applications of enteral nutrition

Clinical and experimental evidence confirms that delivery of nutrients via the gastrointestinal tract reduces septic morbidity in critically injured patients. Early enteral feeding seems to maintain mucosal integrity and to support the gut as an important immunologic organ that may affect other areas of the body. There is increasing evidence to suggest that specific nutrients are especially beneficial in maintaining intestinal host-defense function in times of critical illness and injury.

Is resection with primary anastomosis following destructive colon wounds always safe?

Resection with primary anastomosis was associated with a 14% anastomotic leak rate in this review of 60 patients with destructive colon wounds. The presence of an underlying medical illness or massive blood transfusion was associated with anastomotic complications. In the high-risk subset of patients who had one or both of these risk factors, the anastomotic leak rate was 42%. The incidence of anastomotic leak in previously healthy patients without massive transfusion was 3%. Ileocolostomies were no safer than colocolostomies. We conclude that resection with anastomosis should not be performed on all patients with destructive colon injuries, as the risk of anastomotic leak is prohibitive in those with either massive blood loss or underlying medical illness. We continue to perform primary anastomosis in healthy patients without excessive blood loss.

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.

Traumatic hepatic artery pseudoaneurysm with hemobilia

Hepatic artery pseudoaneurysm (HPA) with hemobilia is an unusual complication of hepatic trauma. Initial operative management can have an impact on the development of HPA, and definitive management is difficult. A total of 482 consecutive patients with liver injury were prospectively analyzed. Six of these (1.2%) developed HPA with hemobilia. Three patients developed HPA after penetrating injuries, and 3 after blunt trauma. All 6 patients had hemobilia with massive upper gastrointestinal hemorrhage; HPA was confirmed by angiography. A total of 80% had bile leaks as revealed by hepatobiliary scans. One patient was nonseptic and had a small intrahepatic cavity, and the patient underwent successful embolization of the HPA. The remaining 5 had unexplained sepsis with large intrahepatic cavities and underwent operation. Two died due to massive blood loss and coagulopathy during attempted cavity débridement prior to gaining vascular control. One had right hepatic artery ligation in lieu of resection and subsequent lobectomy after recurrence of hemobilia; the other 2 had formal hepatic resections. No survivors had further rebleeding. We conclude that (1) HPA with hemobilia is predisposed by bile leak; (2) embolization appears appropriate for patients with small cavities without sepsis; and (3) débridement and drainage, which may require formal resection, are necessary for those with large cavities and/or sepsis after vascular control is obtained either by preoperative embolization or intraoperatively.

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.