Meta-analysis of the effect of peritoneal lavage on survival in experimental peritonitis.

BACKGROUND: : Morbidity and mortality associated with bacterial peritonitis remain a challenge for contemporary surgery. Despite great surgical improvements, death rates have not improved. A secondary debate concerns the volume and nature of peritoneal lavage or washout-what volume, what carrier and what, if any, antibiotic or antiseptic? METHODS: : A literature search of experimental studies assessing the effect of peritoneal lavage following peritonitis was conducted using Medline, EMBASE and Cochrane databases. Twenty-three trials met predetermined inclusion criteria. Data were pooled and relative risks calculated. RESULTS: : In an experimental peritonitis setting a mortality rate of 48.9 per cent (238 of 487) was found for saline lavage compared with 16.4 per cent (106 of 647) for antibiotic lavage (absolute risk reduction (ARR) 32.5 (95 per cent confidence interval (c.i.) 27.1 to 37.7) per cent; (P < 0.001). An ARR of 25.0 (95 per cent c.i. 17.9 to 31.7) per cent P < 0.001) was found for the use of saline compared with no lavage at all. The survival benefit persisted regardless of systemic antibiotic therapy. Antiseptic lavage was associated with a very high mortality rate (75.0 per cent). CONCLUSION: : Pooled data from studies in experimental peritonitis demonstrated a significant reduction in mortality with antibiotic lavage.

Thermal injury in the elderly: when is comfort care the right choice?

The factors contributing to a higher mortality rate in elderly thermal injury victims are not well delineated. The purpose of this study is to determine the impact of the initial injury, medical comorbidities, and burn size on patient outcome and to determine a level of injury in this population when comfort care is an appropriate first choice. Individual medical records of patients over 65 years of age admitted to our burn center over a 10-year interval were reviewed for patient demographics, mechanism of injury, total body surface area (TBSA) burned, medical comorbidities, use of Swan-Ganz catheters, evidence of inhalation injury, level of support, and patient outcome. The mechanisms of thermal injury were flame (68%), scald (21%) and electrical or chemical contact (11%). Twenty-six preventable bathing, cooking, and smoking-related injuries were seen (33%). The average TBSA was 25 per cent. Average length of stay varied depending on outcome. The overall mortality rate for this group was 45 per cent. Patients older than 80 years with 40 per cent or greater TBSA burned had a 100 per cent mortality rate despite aggressive treatment. Burn wound size correlated better with probability of poor outcome than age. Thermal injuries in the elderly are becoming more important with the aging of our population. Underlying medical problems--specifically chronic obstructive pulmonary disease--do play a role in increased patient morbidity and mortality. This study shows that age greater than 80 years in combination with burns greater than 40 per cent TBSA are uniformly fatal despite aggressive therapy. We believe that delaying the start of comfort-only measures in this situation only prolongs the pain and suffering for the patient, the family, and the physician.

Early elevation of soluble CD14 may help identify trauma patients at high risk for infection.

BACKGROUND: Elevated levels of soluble CD14 (sCD14) have been implicated in both gram-positive and gram-negative sepsis, and it has been associated with high mortality in trauma patients who become infected. METHODS: Eleven healthy volunteers and 25 adult trauma patients with multiple injuries and a mean Injury Severity Score of 32 participated. Whole blood was obtained at intervals. Immunohistochemistry was used to quantify membrane CD14 (mCD14), by flow cytometry and plasma levels of sCD14 by enzyme-linked immunosorbent assay. Analysis of variance and Student's T test with Mann-Whitney posttest were used to determine significance at p < 0.05. RESULTS: On posttrauma day 1, sCD14 was significantly different in the plasma of infected patients compared with normal controls (7.16 +/- 1.87 microg/mL vs. 4.4 +/- 0.92 microg/mL, p < 0.01), but not significantly different from noninfected patients. The percentage of monocytes expressing mCD14 in trauma patients did not differentiate them from normal controls; however, mCD14 receptor density did demonstrate significance in septic trauma patients (n = 15) versus normal controls on posttrauma day 3 (p = 0.0065). CONCLUSION: On the basis of our data, mCD14 did not differentiate infected and noninfected trauma patients, although trauma in general reduced mCD14 and elevated sCD14. Interestingly, 100% of patients who exceeded plasma levels of 8 microg/mL of sCD14 on day 1 after injury developed infections. Therefore, early high expressers of sCD14 may be at higher risk for infectious complications after trauma.

Evolution in the treatment of complex blunt liver injuries.

Over the last decade, major changes in the treatment of patients with blunt liver injuries have occurred, specifically with the nonoperative treatment of more complex injuries. These major changes can be summarized as follows: 1. Patients with blunt liver injuries are screened expeditiously by surgeon-performed ultrasonography. Depending on the initial findings and response to resuscitation, further decisions are made regarding the further evaluation. 2. Computed tomographic scanning is the mainstay of diagnosis for hepatic injuries after blunt trauma; the initial CT findings will help the trauma surgeon to determine the nonoperative treatment. 3. Liver injuries of grades I through III can be observed safely in a monitored unit and not necessarily in an ICU setting. Patients with injuries of grades IV and V are best initially observed in an ICU. 4. More than two thirds of patients with injuries of grades IV and V can be treated nonoperatively. However, 50% of these patients will require some type of interventional treatment, but not necessarily a laparotomy. 5. Initial findings on the CT scan can help to identify those patients who will need some type of interventional treatment and to identify associated injuries. 6. Elderly patients or patients with associated medical comorbidities can also be treated nonoperatively if strict guidelines are followed. 7. Complications in patients with complex blunt liver injuries are not uncommon. However, most of the complications can be safely treated by less invasive procedures.

Early decrease in surface expression of HLA-DQ predicts the development of infection in trauma patients.

The behaviour of human leucocyte antigen-DR (HLA-DR) following injury has been extensively studied. However, the behaviour of other class II antigens following trauma has not been characterized as well, despite evidence that HLA-DQ genotype influences the response to several bacterial antigens. Our study attempts to characterize and analyse the behaviour of HLA-DQ after trauma in patients with and without infection. Twenty-five patients were studied following major injury. Fifteen of the 25 patients developed infection (men = 11, women = 4); 10 patients developed no infection (men = 9, women = 1). The mean age was 34 +/- 12 years for patients with no infection and 52 +/- 20 years for those with infection. Monocyte HLA-DQ surface expression was determined using FITC-labelled antibodies and flow cytometry. Expression was compared with a control population of 11 healthy volunteers. The percentage of monocytes expressing HLA-DQ following trauma was reduced in patients with infection and in those without infection, but returned to normal (days 8-14) only in those patients who did not develop infection. Monocyte HLA-DQ mean channel fluorescence was reduced on day 1, but quickly returned to normal in those patients who subsequently developed infection. Stimulated with lipopolysaccharide, the initial samples of 13 patients who developed infection showed that surface expression on these monocytes could be elevated into the normal range. We conclude that HLA-DQ is an additional early marker of outcome that may not function merely as an immune suppressor. The maintained ability of HLA-DQ to present self-antigens may be important in the initial stages of the host response to injury.

Evolution in the management of hepatic trauma: a 25-year perspective.

OBJECTIVE: To define the changes in demographics of liver injury during the past 25 years and to document the impact of treatment changes on death rates. SUMMARY BACKGROUND DATA: No study has presented a long-term review of a large series of hepatic injuries, documenting the effect of treatment changes on outcome. A 25-year review from a concurrently collected database of liver injuries documented changes in treatment and outcome. METHODS: A database of hepatic injuries from 1975 to 1999 was studied for changes in demographics, treatment patterns, and outcome. Factors potentially responsible for outcome differences were examined. RESULTS: A total of 1,842 liver injuries were treated. Blunt injuries have dramatically increased; the proportion of major injuries is approximately 16% annually. Nonsurgical therapy is now used in more than 80% of blunt injuries. The death rates from both blunt and penetrating trauma have improved significantly through each successive decade of the study. The improved death rates are due to decreased death from hemorrhage. Factors responsible include fewer major venous injuries requiring surgery, improved outcome with vein injuries, better results with packing, and effective arterial hemorrhage control with arteriographic embolization. CONCLUSIONS: The treatment and outcome of liver injuries have changed dramatically in 25 years. Multiple modes of therapy are available for hemorrhage control, which has improved outcome.

Endotoxin and muramyl dipeptide modulate surface receptor expression on human mononuclear cells.

Endotoxin (lipopolysaccharide (LPS), 100 ng/ml) and muramyl dipeptide (MDP 100 ng/ml), two immunomodulatory bacterial cell wall products, were incubated with human whole blood, and the expression of receptors involved in antigen presentation, costimulation, and cell activation was investigated by use of flow cytometry. On monocytes, LPS and MDP increased surface expression of human leukocyte antigen-DR (HLA-DR), CD18, CD54 (intercellular adhesion molecule-1, ICAM-1), and CD86 (B7-2). On lymphocytes, LPS but not MDP increased HLA-DR expression after 18 h. The expression of CD28, CD49d/CD29, and CD106 (vascular cell adhesion molecule-1, VCAM-1) remained unchanged on both monocytes and lymphocytes. The early increase (1-6 h) of CD18 and ICAM-1 expression led us to hypothesize that CD18-dependent costimulatory signals were involved in the later (6 h) increase of monocyte HLA-DR expression. However, blocking studies using monoclonal antibodies against CD18 (IB4, 15 microg/ml) demonstrated that the LPS- and MDP-induced increase of HLA-DR and ICAM-1 expression on monocytes was not mediated through CD18. LPS induced the expression of the early activation marker CD69 by a CD14-dependent but CD18-independent mechanism, whereas MDP did not induce CD69 expression. Analysis of leukocyte subsets demonstrated that CD4(+) T-cells, CD8(+) T-cell, CD19(+) B-cells, CD56(+) natural killer (NK)-cells, and CD14(+) monocytes increased the expression of CD69 after stimulation with LPS. Collectively, these data demonstrate a stronger immunomodulatory effect of LPS compared with MDP which may, in part, explain the established difference of toxicity between these two bacterial cell wall products.

Microsatellite marker of interferon-gamma receptor 1 gene correlates with infection following major trauma.

BACKGROUND: This study hypothesizes that predicted polymorphism of the interferon-gamma receptor 1 gene may play an important role in infection after trauma as supported by microsatellite analysis. METHODS: DNA was extracted from the peripheral leukocytes of 38 trauma patients with Injury Severity Scores greater than 16. D6S471, a microsatellite marker on chromosome 6 near interferon-gamma receptor 1, was amplified with polymerase chain reaction, and genotypes were determined. RESULTS: The mean Injury Severity Score was 32, and 63% of patients (24 of 38) developed major infection. Three alleles and 5 genotypes were identified for D6S471. Twenty-six percent of patients (10 of 38) had genotype AA, all of whom developed major infection (P =.004). Genotype BB accounted for 57% of the uninfected population (8 of 14) but only 21% of the infected group (P =.028). Allele A had a frequency of 33%, of which 22 alleles (88%) were found in infected patients (P =.001). In addition, allele B accounted for 61% of the uninfected group (17 of 28) but only 23% (11 of 48) of the infected group (P =.001). Allele C demonstrated no correlation. CONCLUSIONS: Microsatellite polymorphism correlates strongly with infection. These findings portend polymorphism in the receptor itself and thereby represent a genetic basis for the development of infection. We suggest this identifies a high-risk group who could benefit from more specific therapy that may have the potential to overcome this receptor insufficiency.

Multifactorial analyses in the diagnosis of pneumonia arising in the surgical intensive care unit.

The diagnosis of ventilator-associated pneumonia in the surgical intensive care unit continues to be problematic. The majority of intensive care units use clinical criteria based on chest x-ray; fever; leukocytosis; alterations in the pulse oximeter observations; the need to alter modes and amounts of ventilatory support; and more specific microbiologic studies, such as appropriate sputum, Gram stain, and culture to identify pneumonia. Diagnosing pneumonia based on clinical criteria alone is often difficult and inaccurate, which may lead to inappropriate use and choice of antibiotics. Invasive diagnostic techniques, such as protected specimen brush and bronchoalveolar lavage, provide an important microbiologic diagnosis. However, the cost and inconvenience limit broad usage. Furthermore, those results that return positive are often too late to dictate the need for, or direction of, therapy. Our use of a "pneumonia grid" may help identify patients likely to have a poor outcome. Until a readily available and cost-effective diagnostic study for pneumonia is developed, clinical criteria remain vital in routine practice.

Immunologic responses to pneumonia.

Pneumonia in the critically ill surgical patient often results from the bombardment of a previously normal pulmonary system with therapeutic foreign bodies, hospital pathogens, and impairment of the host defenses. Despite its long history as a significant clinical problem, a woefully inadequate amount of study has been directed toward therapy. We created an experimental model of a differential pulmonary infection using a strain of Klebsiella pneumoniae. We then compared the progressively affected pneumonic process versus the normal parenchyma. We measured neutrophil and monocyte complement antibody receptor expression and monocyte and macrophage class II major histocompatibility antigens (HLA-DR) via percent of cells and mean fluorescent intensity outcomes from flow cytometry. The main difference between infected versus noninfected tissues was monocyte DR expression, which was consistently depressed in cells from infected parenchyma. What follows is a discussion of the implications of this work as well as other work in the immunology of pneumonia and cytokine expression. Possible therapeutic modalities are included.

Should trauma surgeons do general surgery?

OBJECTIVE: Many trauma centers have separated emergency and general surgery from trauma care. However, decreased trauma volume and more frequent nonoperative management may limit operative experience and the economic viability of the trauma service. Trauma surgeons at our Level I trauma center have long provided all emergency surgical care and elective surgery. We sought to determine the impact of this policy. METHODS: We reviewed all admissions to the trauma service from June of 1992 to July of 1998 and cross-referenced this with our trauma registry. The number of major and minor procedures performed was also determined, and we reviewed all operative procedures by the trauma service for June of 1996 to October of 1998. RESULTS: Total admissions by the trauma service averaged 3,003 patients/year (range, 2,798-3,198 patients). Nontrauma patients accounted for 34% of all trauma service admissions (range, 26-40%). During this time period, there was no change in volume of operative or intensive care unit procedures, whereas minor procedures recently decreased from a peak of 141/month to 50/month. This was largely due to decreased use of diagnostic peritoneal lavage (surgeon reimbursable) and an increased use of computed tomographic scan and ultrasound (not presently reimbursed) to evaluate blunt abdominal trauma. During the past 2 years, nontrauma cases accounted for 33% of all operative procedures by the trauma service. CONCLUSIONS: Maintenance of emergency and general surgical care by the trauma service has allowed us to buffer impact of variations in trauma volume and to maintain operative skills in an era of increased nonoperative management of many injuries.

Prophylactic antibiotics in surgery and surgical wound infections.

Wound infection remains a considerable cause of morbidity and mortality among surgical patients, despite the relative success of prophylactic antibiotics. In modern efforts to control healthcare costs while improving the quality of patient care, we must not overlook the basic principles of wound infections and their appropriate treatment. Predisposing factors for the development of surgical wound infection include the creation of a surgical wound, the presence of bacteria, and a susceptible host. The selection of an appropriate antimicrobial drug depends on the identification of the most likely pathogens associated with a given procedure, as well as the expected antibiotic susceptibility of those pathogens. Ideally, a prophylactic antibiotic should achieve high peak tissue concentration at the site of the wound before the first incision and should be maintained until the time of closure. Currently, the administration of prophylactic antibiotics is indicated for contaminated and clean-contaminated wounds. Despite the proven effectiveness of antibiotic prophylaxis, many researchers would argue that contemporary dosing regimens should be reevaluated. The debates concerning the dosage and timing of ideal prophylactic administration are likely to continue.

Empyema and restrictive pleural processes after blunt trauma: an under-recognized cause of respiratory failure.

Respiratory failure is a common complication among patients sustaining major blunt trauma. This is usually due to the underlying pulmonary injury, pneumonia, or adult respiratory distress syndrome. However, we have frequently found these patients to actually have a pleural process as the cause of their respiratory failure. Our objective was to assess the frequency of empyema and restrictive pleural processes after blunt trauma and their contribution to respiratory failure. We retrospectively reviewed all blunt trauma patients over a 5-year period who required a thoracotomy and decortication for empyema. Twenty-eight patients with blunt trauma required a thoracotomy and decortication for empyema. The most common finding was infected, loculated hemothorax/effusion in 23 patients, whereas 5 had an associated pneumonia. Chest radiographs were nondiscriminating, whereas CT scans in 25 patients showed previously unrecognized fluid collections, air-fluid levels, or gas bubbles. Neither thoracentesis nor placement of additional chest tubes was helpful. Positive cultures were uncommon. Ventilator dependence was present preoperatively in 13 patients who were on the ventilator an average of 13 days preoperatively and only 5.8 days postoperatively. Several patients believed to have adult respiratory distress syndrome were weaned within 72 hours of operation. All patients were ultimately cured. Empyema is an under-recognized complication of blunt trauma and may contribute to respiratory failure and ventilator dependence. Although difficult to diagnose, empyema should be considered in blunt trauma patients with respiratory failure and an abnormal chest radiograph. CT aids in the diagnosis, and the results of surgical treatment are excellent.

The continuing challenge of Fournier's gangrene in the 1990s.

Fournier's disease is a potentially fatal acute, gangrenous infection of the scrotum, penis, or perineum associated with a synergistic bacterial infection of the subcutaneous fat and superficial fascia. Thrombosis of small subcutaneous arterioles with resultant ischemia contributes to the rapid extension of the infection. During a 12-year period, the clinical and operative records of 14 patients with Fournier's gangrene were analyzed. All patients were treated with broad spectrum antibiotics and serial surgical debridements. Nine patients had polymicrobial isolates from the initial wound culture; two patients had Group A Streptococcus species as the sole isolate. The etiology of the infection was identified in 12 patients. Five patients died for an overall mortality of 38 per cent. The mean age of survivors was 51 years compared with 75 years for nonsurvivors (P<0.05). The last six patients in this series survived. The mean hospital stay was 29 days. Four patients (31%) had a prior history of diabetes; however, 11 patients (85%) had elevated serum glucose levels (>120 mg/dL) on admission. All patients were hypoalbuminemic on admission. Survivors had an average serum creatinine on admission of 1.28 mg/dL compared with 3.1 mg/dL for nonsurvivors. Although supportive care is required in these patients, the mainstay for treatment of Fournier's gangrene entails an aggressive approach with frequent and extensive soft tissue debridements to control the invasive nature of the infection with delayed wound coverage once the infection has been controlled. Elderly patients with evidence of renal dysfunction on admission have a poor prognosis despite aggressive therapy.