Hydrated vs. freeze-dried human acellular dermal matrix for hernia repair: a comparison in a rabbit model.

BACKGROUND: Abdominal wall hernias commonly occur following laparotomy. Biologic grafts are used to treat these hernias due to their biocompatibility and their ability to serve as a matrix for tissue regeneration and remodeling. Freeze-dried human acellular dermal matrices (F-HADMs) have been shown to be effective in abdominal wall defect repair. Hydrated human acellular dermal matrices (H-HADMs) have not been previously evaluated. This study evaluates H-HADM and F-HADM in the repair of abdominal wall hernias in the rabbit. METHODS: Thirty-six 3-4-kg New Zealand white rabbits underwent laparotomy with the creation of a hernia. After defect reperitonealization, the animals underwent hernia repair with H-HADM, F-HADM, or primary repair. Within each group, four animals were survived for 4, 8, and 20 weeks. The outcomes evaluated included recurrences, adhesions, histology, immunohistochemistry, and tensiometry. RESULTS: Thirty-five animals underwent abdominal wall hernia repair. One animal in the F-HADM group developed a recurrent hernia. No significant difference was demonstrated in adhesion scores between the H-HADM (0.75) and F-HADM (0.83) groups. Tensiometry demonstrated no differences in the forces required to disrupt the graft from the native fascia between H-HADM and F-HADM at any time point. H-HADM demonstrated fewer white blood cells (WBC) and eosinophils (EOS) per high-powered field (hpf) than F-HADM at 4 weeks (144 WBC/hpf vs. 534 WBC/hpf, P < 0.05; 87 EOS/hpf vs. 304 EOS/hpf, P < 0.05) and 8 weeks (104 WBC/hpf vs. 314 WBC/hpf, P < 0.05; 41 EOS/hpf vs. 149 EOS/hpf, P < 0.05). At 20 weeks, there was no difference in WBC or EOS (134 WBC/hpf vs. 144 WBC/hpf, P = NS; 86 EOS/hpf vs. 104 EOS/hpf, P = NS). Immunohistochemistry for CD31 demonstrated no difference in vascularity at any time point. CONCLUSIONS: H-HADM and F-HADM demonstrate comparable results in abdominal wall hernia treatment in a rabbit model. With both grafts, the weakest area of the repair occurs at the graft and native fascia interface. Hernia repairs with H-HADM and F-HADM demonstrate similar incidences of adhesions and tensile strength characteristics. H-HADM demonstrates a reduced inflammatory response at 4 and 8 weeks compared to F-HADM. Both H-HADM and F-HADM demonstrate similar amounts of vascular ingrowth.

Systems ambiguity and guideline compliance: a qualitative study of how intensive care units follow evidence-based guidelines to reduce healthcare-associated infections.

BACKGROUND: Consistent compliance with evidence-based guidelines is challenging yet critical to patient safety. We conducted a qualitative study to explore the underlying causes for non-compliance with evidence-based guidelines aimed at preventing four types of healthcare-associated infections in the surgical intensive care unit (SICU) setting. METHODS: Twenty semistructured interviews were conducted with attending physicians (3), residents (2), nurses (6), quality improvement coordinators (3), infection control practitioners (2), respiratory therapists (2) and pharmacists (2) in two SICUs. Using a grounded theory approach, we performed thematic analyses of the interviews. RESULTS: The concept of systems ambiguity to explain non-compliance with evidence-based guidelines emerged from the data. Ambiguities hindering consistent compliance were related to tasks, responsibilities, methods, expectations and exceptions. Strategies reported to reduce ambiguity included clarification of expectations from care providers with respect to guideline compliance through education, use of visual cues to indicate the status of patients with respect to a particular guideline, development of tools that provide an overview of information critical for guideline compliance, use of standardised orders, clarification of roles of care providers and use of decision-support tools. CONCLUSIONS: The concept of systems ambiguity is useful to understand causes of non-compliance with evidence-based guidelines aimed at reducing healthcare-associated infections. Multi-faceted interventions are needed to reduce different ambiguity types, hence to improve guideline compliance.

Group A Streptococcus (GAS) soft-tissue infections: a lethal organism on the rise.

Several reports over the past decade have suggested that there has been an increase in the number of invasive streptococcal infections with young children and the elderly being at the highest risk. We evaluated the incidence of group A Streptococcus (GAS) and compared it with historic data collected at our institution. Prospective data were collected on patients diagnosed with GAS (with and without shock) admitted to a tertiary-care center from July 1995 to July 2000. Each patient was followed by an infectious disease specialist throughout the hospital stay. Definitions of streptococcal toxic shock syndrome (STSS) developed by the Centers for Disease Control and Prevention were used. Thirty-eight patients (mean age of 39+/-12) presenting with GAS soft-tissue infections were admitted to our institution over a 5-year period (7.6 patients per year). Fourteen (37%) were diagnosed with STSS. This represents a greater than fourfold increase in the average number of cases per year of patients diagnosed with GAS and a nearly 4.5 times greater increase in the annual number of patients diagnosed with STSS. The overall mortality of patients diagnosed with GAS was 13 per cent, which increased to 36 per cent in patients diagnosed with STSS. We conclude that there has been a significant increase in the incidence of GAS soft-tissue infections over the past 5 years at our institution. This may represent a new virulent strain, as the majority of these infections did not occur in typical high-risk patients at the extremes of their lives. Further epidemiologic population-based studies are needed to further delineate the severe nature of this problem.

Incidental pregnancy in trauma patients.

BACKGROUND: The rate of incidental pregnancy in trauma patients and the incidence of associated fetal mortality, to our knowledge, have not been previously reported. The early diagnosis of pregnancy in trauma patients has become even more difficult because rapid pregnancy screens have been eliminated because of quality control issues. We determined the rate of incidental pregnancy and the sequelae of delayed diagnosis, including fetal radiation exposure and mortality. STUDY DESIGN: Data were analyzed retrospectively on all patients in whom pregnancy was diagnosed during a trauma admission during a 4-year period (1995 to 1999). Pregnancy was confirmed by beta-HCG testing and gestational age estimated by an obstetrician by ultrasonography. Pregnancy outcomes were determined by a prospective telephone survey. RESULTS: One hundred fourteen (2.9%) of the 3,976 women (age 15 to 40 years) admitted to the trauma center were found to be pregnant. Thirteen (11.0%) were incidental pregnancies, of which 9 (8.0%) were newly diagnosed. Mean gestational age was significantly lower in the newly diagnosed pregnancies (6.9 versus 20.5 weeks, p < 0.0005). Fetal mortality in this group was significantly higher (100% versus 25%, p < 0.0005). The mean initial radiation exposure of all patients was 4.5 rads. Cumulative radiation exposure exceeded 5 rads in 85% of patients. CONCLUSIONS: Trauma patients diagnosed with incidental pregnancy are routinely exposed to doses of radiation exceeding the recommendations of the American College of Obstetrics and Gynecologists. Reinstitution of the rapid pregnancy test should be considered in all female trauma victims of childbearing age. This may promote a reduction in fetal radiation exposure and perhaps influence a portion of the fetal mortality in those patients with newly diagnosed incidental pregnancy.

Systemic inflammatory response syndrome score at admission independently predicts infection in blunt trauma patients.

BACKGROUND: Systemic inflammatory response syndrome (SIRS) score has been demonstrated to be an accurate predictor of outcome in critical surgical illness. To our knowledge, there is a paucity of data using SIRS score as a tool to predict posttraumatic infection. Our goal was to determine whether the severity of SIRS score at admission is an accurate predictor of infection in trauma patients. METHODS: Prospective data were collected on 4,887 blunt trauma patients admitted to a primary adult resource center designated trauma center over an 18-month period. Patients were stratified by age and Injury Severity Score (ISS). SIRS score was calculated at admission. SIRS was defined as an SIRS score > or = 2. Each patient was screened for infection by an infectious disease specialist. Those at high risk for infection were then monitored daily throughout their hospitalization. Centers for Disease Control and Prevention guidelines were used to diagnose infection. RESULTS: Of the 4,887 patients, 1,850 (38%) were admitted > 24 hours and evaluated for subsequent infection (mean ISS, 16 +/- 9; mean age, 43 +/- 19, SD). Thirty-one percent (577) of the patients acquired an infection. The mean hospital length of stay (20.2 days vs. 6.5 days) and mortality (7.8% vs. 2.7%) were significantly greater in the infected group (p < 0.001). Of the four SIRS variables (temperature, heart rate, white blood cell count, and respiratory rate), hypothermia and leukocytosis were the most significant predictors of infection (p < 0.001) when adjusted for age and ISS. SIRS scores of > or = 2 were increasingly predictive of infection when analyzed by multiple logistic regression analysis. CONCLUSION: An admission SIRS score of > or = 2 is a significant independent predictor of infection and outcome in blunt trauma. Daily SIRS scores may be a meaningful method of assessing postinjury risk of infection, and may initiate earlier diagnostic intervention for determination of infection.

Total cytokine immunoassay: a more accurate method of cytokine measurement?

BACKGROUND: Cytokines signal the normal processes of inflammation and repair in all organs, yet the aberrant expression of these peptide mediators is associated with significant organ dysfunction. The accurate measurement of cytokines is therefore critical. In this study, we sought to investigate the alterations in cytokine expression early after trauma in humans using a new competitive binding immunoassay that measures both free and bound cytokine and compare this with standard enzyme-linked immunosorbent assay (ELISA), which measures only free cytokine. METHODS: Peripheral blood was obtained from trauma patients at admission. Exclusion criteria were transfers, death within 24 hours, pregnancy, known acquired immunodeficiency syndrome, chemotherapy, transplant, or other chronic immune disorder. "Total" cytokine immunoassay was compared with ELISA for cytokines (interleukin [IL]-1, IL-6, and IL-10) measured in serum. RESULTS: Cytokine concentrations measured by total immunoassay were significantly higher (10- to 500-fold increase) than those measured by ELISA, and correlation between the two methods was poor (r2 = 0.193 for IL-10). No significant differences in mean serum cytokine concentrations were noted between trauma patients and normal controls for IL-1 (56 vs. 37 pg/mL), IL-6 (16 vs. 25 pg/mL), and IL-10 (4 vs. 26 pg/mL) using the ELISA method. In contrast, trauma patients had significantly higher serum concentrations of IL-1 (3,320 vs. 1,470 pg/mL, p < 0.05), IL-6 (2,415 vs. 1,048 pg/mL, p < 0.05), and IL-10 (2,307 vs. 1,480 pg/mL, p < 0.05) at admission compared with normal controls using total cytokine immunoassays. CONCLUSION: Cytokine measurements in peripheral blood in trauma patients and normal controls are significantly (10- to 500-fold) higher when using a total cytokine assay that measures both free and bound cytokine. Competitive immunoassays may be the method of choice when measuring endogenous cytokine levels in biologic fluids, and new normal ranges for cytokines must be established for future accurate research in critical care and trauma.

Impact of nosocomial infections in trauma: does age make a difference?

BACKGROUND: The effect of age and infection on outcome after trauma is unknown. We evaluated the incidence and impact that nosocomial infection (NI) and age have on morbidity and mortality. Several risk factors were identified and analyzed for correlation with infection. METHODS: Prospective data were collected on patients admitted for > or = 3 days over a 2-year period. Each patient was followed by an infectious disease specialist throughout their hospitalization. Centers for Disease Control and Prevention guidelines were used to diagnose infection. RESULTS: Of the 3,254 patients admitted, 88% were < 65 and 12% were > or = 65 years of age. Injury Severity Score was not significantly different (older vs. younger). Five hundred one (17.4%) of the younger patients developed an NI with a significantly higher hospital length of stay (LOS), intensive care unit (ICU) LOS, and mortality compared with the noninfected group. One hundred forty-seven (39%) of the older group developed an NI and also had significant increases in hospital LOS, ICU LOS, and mortality. Older infected patients had the highest hospital LOS, ICU LOS, and mortality. The greatest relative risk of mortality was demonstrated with the combination of increased age and NI. Once infected, however, younger patients with penetrating trauma had a greater relative risk of mortality in the group-specific comparison. Many risk factors were associated with infection. Only chronic obstructive pulmonary disease in elderly trauma patients was a significant independent risk factor for infection. CONCLUSION: NI significantly increases hospital LOS, ICU LOS, and mortality after injury. Age increases risk of infection matched for injury severity, with a significantly higher hospital LOS, ICU LOS, and mortality. Once infected, however, younger patients with penetrating trauma have the greatest risk of mortality. Chronic obstructive pulmonary disease in elderly trauma patients was found to be an independent predictor of infection.

Prophylactic chlorhexidine oral rinse decreases ventilator-associated pneumonia in surgical ICU patients.

BACKGROUND: Pneumonia is one of the most common nosocomial infections in hospitalized patients. The risk of nosocomial pneumonia increases with age, severity of acute illness and preexisting co-morbid conditions. Ventilator-associated pneumonia (VAP) significantly increases morbidity, length of stay, resource utilization and mortality. The purpose of this study was to determine whether adherence to a ventilator weaning protocol (WP) and the use of chlorhexidine gluconate (CH) oral rinse for oral hygiene would decrease the incidence of VAP in surgical ICU patients. METHODS: A prospective study was conducted over a period of 10 months (October 1998-July 1999) in surgical ICU patients requiring mechanical ventilation (n = 95). During the first 5 months, a WP was applied to all patients requiring mechanical ventilation. During the following 5 months, a CH 0.12% oral rinse administered twice daily was added to the protocol, initiated on ICU admission in all intubated patients. The data collection included age, gender, race, risk factors, co-morbid conditions, severity of the acute illness (APACHE II) at admission, duration of ventilation, ICU and total-hospital length of stay, and incidence of VAP and in-hospital mortality rates. Both WP and WP+CH groups were compared using the National Nosocomial Infection Surveillance (NNIS) and hospital databases as historic controls. RESULTS: The institution of the WP alone led only to a slight decrease in the incidence of VAP but a significant reduction in the median duration of mechanical ventilation by 40% (4.5 days, p < 0.008). The addition of CH to the WP led to a significant reduction and delay in the occurrence of VAP (37% overall, 75% for late VAP, p < 0.05). The median duration of mechanical ventilation in this group was similar to that of the WP group. There was no significant difference in the overall hospital or ICU length of stay between the groups. CONCLUSIONS: Improved oral hygiene via topical CH application in conjunction with the use of a WP is effective in reducing the incidence of VAP and the duration of mechanical ventilation in surgical ICU patients.

Community-acquired infections in the geriatric trauma population.

The incidence of community-acquired infections (CAs) and their relationship to the incidence of nosocomial infections (NI), to our knowledge, is unknown in elderly trauma patients. We prospectively collected data on 380 patients > or =65 years of age who were admitted >48 h to our trauma center over a 2-year period. One hundred seventy-seven patients (47%) developed an infection. A total of 147 (39%) patients were diagnosed with an NI, and 67 (18%) were diagnosed with a CA. Of the 67 patients with CA, 37 (55%) went on to develop an NI. Patients with the combination of CA and NI had the greatest mean ICU (28.6 days) and hospital length of stay (38.2 days). Mortality was increased significantly in patients with the combination of CA and NI (27%). Respiratory and genitourinary infections were the most common CA. Patients with respiratory CAs accounted for the greatest proportion of NIs. Thus, community-acquired and nosocomial infections significantly increase morbidity and mortality in elderly patients post-injury. Patients who present with a CA are at increased risk of acquiring an NI, which is associated with the most significant increase in length of stay and mortality.

Esophageal involvement in Behçet's syndrome.

Two patients with Behçet's syndrome had severe esophageal involvement. Both presented the complete clinical pattern (oral, genital, and eye lesions) of Behçet's syndrome. In both, esophageal lesions were associated with other gastrointestinal manifestations, in the first a transient episode of ulcerative ileitis, and in the second patient colitis. In both, the differential diagnosis with inflammatory bowel disease was very difficult. Histology of esophageal lesions was nonspecific; no vasculitis was found. Both patients improved on steroid therapy. Esophageal lesions also improved endoscopically and histologically with steroid therapy. When there is obvious gastrointestinal involvement in Behçet's syndrome, the differential diagnosis from inflammatory bowel disease is very difficult.

Relapsing polychondritis with severe aortic insufficiency.

Relapsing polychondritis (RP) is a rare disease characterized by auricular, nasal and respiratory tract chondritis, ocular inflammation, inflammatory polyarthritis and cardiovascular abnormalities. Here we describe a patient with a five-year history of mild nasal and auricular chondritis, which suddenly developed into a severe aortic insufficiency with rest dyspnea. The pathogenesis and the management of this rare connective tissue disease are discussed.

[Blood catecholamines in liver cirrhosis]. / Le catecolamine ematiche nella cirrosi epatica.

Haematic concentrations of catecholamines were found to be higher in cirrhotic patients with ascites, than cirrhotic patients without ascites and controls. In compensated and decompensated cirrhosis, different forms of sympathetic nervous activity were observed. The high catecholamine values in cirrhotic patients and the activation of the renin angiotensin-aldosterone system suggest the use of beta-blockers to reduce sodium-water retention.

Chronic active hepatitis and Behçet's syndrome.

In a patient with Behcet's syndrome the finding of five times the normal level of serum transaminase accompanied by weakness may be correlated to the syndrome itself. We performed needle biopsy of the liver in our patient which showed piecemeal necrosis and portal lympho-monocytic infiltration extending into the lobule. It is interesting that HLA B5 and B27 antigens were present. Simultaneous occurrence of chronic active hepatitis and Behcet's syndrome may imply the same autoimmune pathogenesis, as we suggest in this work.