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Biomedical subjects

M A Croce

Publications and source records attributed to M A Croce.

At least 91 records · Page 5Linked to original sources

Splanchnic and systemic hemodynamic responses to portal vein endotoxin after resuscitation from hemorrhagic shock.

BACKGROUND: Hemorrhagic shock and sepsis are usually studied separately or in rodents. This study combined the two insults in a large animal model. METHODS: Anesthetized pigs were bled, held in shock for 1 hour, and then resuscitated with fluid. After 3 days, Escherichia coli endotoxin LPS was infused into the portal vein (150 micrograms/kg x 30 min) to mimic the effect of enteric substances breaching the mucosal barrier. Systemic and splanchnic hemodynamics, circulating leukocytes, and plasma levels of tumor necrosis factor (TNF) were measured in five groups: 40% hemorrhage plus fluid only resuscitation, 40% hemorrhage plus fluid-blood resuscitation, 50% hemorrhage plus fluid-blood resuscitation, sham, or sham plus 5 micrograms/kg LPS priming dose instead of hemorrhage. RESULTS: On day 4 before infusion of LPS, there were no differences between groups in hemodynamics or O2 utilization, but systemic O2 delivery and O2 consumption were each reduced in the hemorrhaged groups because of the hemodilution associated with resuscitation. For 3 hours after infusion of LPS, all animals received aggressive fluid and respiratory support, but arterial blood pressure decreased, and systemic O2 utilization, splanchnic O2 utilization, and arterial lactate level increased; there were no differences between groups. In the 50% group compared with sham, LPS-evoked decreases in cardiac index and stroke index were eliminated, and LPS-evoked tachycardia, pulmonary and systemic vasoconstriction, and increases in hepatic and portal vein lactate levels were blunted. Despite similar leukocyte counts before infusion of LPS and similar leukopenia after LPS infusion, plasma LPS level was higher in the 50% group compared with sham. Furthermore, LPS evoked increases in portal and hepatic vein plasma TNF in the shams, but those changes were reduced in the 50% group. CONCLUSIONS: Most responses to LPS were similar after hemorrhagic shock or a sham operation, which is inconsistent with the concept of "priming." LPS-evoked increases in plasma TNF were blunted after shock, probably because of trauma-induced immune dysfunction. A combined shock plus septic challenge in a large animal model may be valuable for investigating the pathogenic mechanism in human beings.

Analysis of Variance↗

Pneumonia and stress ulceration in severely injured patients. A prospective evaluation of the effects of stress ulcer prophylaxis.

Stress ulcer prophylaxis is a routine aspect of the care of critically injured patients. Recent reports have suggested that patients undergoing prophylaxis with histamine antagonists are predisposed to nosocomial pneumonia, and that treatment with sucralfate can prevent this problem. An open, prospective randomized trial of three regimens was conducted with 278 evaluable patients. The patients were assigned to one of three group: the group receiving sucralfate, the group receiving a cimetidine hydrochloride bolus, and the group undergoing continuous infusion with cimetidine. Stress ulceration developed in 8% of patients in the sucralfate group, 13% of patients in the cimetidine bolus group, and 12% of patients in the cimetidine infusion group, while nosocomial pneumonia developed in 29% of patients in the sucralfate group, 32% of patients in the cimetidine bolus group, and 23% of patients in the cimetidine infusion group. Multivariate analysis of risk factors associated with pneumonia demonstrated independent significance for score on the Glasgow Coma Scale, Injury Severity Score, cord injury, shock, and head injury. Only spinal cord injury was associated with stress ulceration. We conclude that sucralfate and cimetidine are both effective for stress ulcer prophylaxis and that there is no association of cimetidine with nosocomial pneumonia.

Administration, Oral↗

A prospective analysis of diagnostic laparoscopy in trauma.

OBJECTIVE: This study was performed to assess current and potential future application for laparoscopy (DL) in the diagnosis of penetrating and blunt injuries. Efficacy, safety, and cost analyses were performed. SUMMARY BACKGROUND DATA: Diagnostic peritoneal lavage (DPL) and computed tomography (CT) have been the mainstays in recent years for diagnosis of equivocal nontherapeutic laparotomy, whereas CT is not helpful for the vast majority of penetrating wounds. DL may be a useful adjunct to fill in these gaps. METHODS: Hemodynamically stable patients with equivocal evidence of intraabdominal injury were prospectively entered into the protocol. DL was performed under general anesthesia; patients with wounds penetrating the peritoneum or blunt injury with significant organ injury underwent laparotomy. RESULTS: Over 19 months, 182 patients (55% stab, 36% GSW, 9% blunt) were studied. No peritoneal penetration was found at DL in 55% of penetrating wounds with 66% of the remainder having therapeutic laparotomy, 17% nontherapeutic laparotomy, and 17% negative laparotomy. Therapeutic laparotomy was performed in 53% of blunt injuries after DL. Tension pneumothorax occurred in one patient and one had an iatrogenic small bowel injury. Charges for DL were $3,325 per patient compared with $3,320 for a similar group undergoing negative laparotomy before this protocol. CONCLUSIONS: DL is a safe modality for trauma. With current technology, DL is most efficacious for evaluation of equivocal penetrating wounds. Significant cost savings would be gained by performance under local anesthesia. Development of miniaturized optics, bowel clamps, retractors, and stapling devices will reduce overall costs and permit some therapeutic applications for laparoscopy in trauma management.

Abdominal Injuries↗

Empiric monotherapy versus combination therapy of nosocomial pneumonia in trauma patients.

Combination therapy for nosocomial pneumonia with a beta-lactam and aminoglycoside is widely accepted because of synergy and reduction of resistant bacteria. This prospective study of 109 trauma patients (94 blunt, 15 penetrating) with nosocomial pneumonia was performed in consecutive phases. In phase 1, patients were randomized to an anti-pseudomonal third-generation cephalosporin--cefoperazone or ceftazidime. Gentamicin was added to each regimen in phase 2. The mean age of the patients was 37 years, the mean ISS was 31, and there were no differences among the four treatment groups relative to associated injuries. Patients receiving monotherapy had a 56% cure rate compared with 31% for combination therapy (p < 0.04). Persistence rates were similar in these two groups (15% and 20%), but superinfection was significantly higher in the combination group (49% vs. 28%; p < 0.04). The predominant superinfecting organism was methicillin-resistant Staphylococcus aureus (MRSA). Nine patients died (5% monotherapy, 10% combination), and eight had a superinfection. We conclude that monotherapy had a higher cure rate than combination therapy for empiric therapy of pneumonia in our trauma patients. Combination therapy failed because of superinfection (primarily MRSA). Emergence of MRSA may be from host overgrowth or plasmid-mediated induction of resistance, possibly caused by gentamicin.

Adolescent↗

Cell-matrix interactions in cultured dermal fibroblasts from patients with an inherited connective-tissue disorder.

Indirect-immunofluorescence studies were performed on cultured dermal fibroblasts from patients with Pseudoxanthoma Elasticum (PXE), an inherited connective-tissue disorder the pathogenesis of which is still unknown. Apparent abnormalities of cytoskeletal structures were revealed by using phalloidin and specific antibodies to alfa-smooth muscle actin and to vimentin. Altered expression of integrin receptors for different extracellular matrix components seems to be present in the pathological cells as preliminary data suggest by using antibodies against alfa subunits of integrins. This study was designed to test the presence of abnormal cell-matrix interactions responsible for the clinical features and involved in the pathogenesis of the PXE disease.

Biotechnology↗

Heparan sulfate fractions: pharmacological properties and effect on smooth muscle cell proliferation in vitro.

In this study we have evaluated the effect of heparan sulfate fractions with different molecular weights on the growth of aortic smooth muscle cells (SMC) of rat in vitro. These fractions were obtained from unfractionated heparan sulfate by a gel filtration technique. The fraction having a molecular weight of 25.5 kDa showed a significant antiproliferative activity only at higher concentrations, while the fractions with molecular weight ranging from 10.7 kDa to 6.8 kDa were effective in reducing cell proliferation at very low concentrations (10(-5) nM and 10(-4) nM). The dose-effect curves are characterized by an initial plateau followed by an increase in effectiveness at the highest concentration. The relationship between molecular weight and antiproliferative activity is discussed.

Animals↗

Interaction of heparan sulfate and its fractions with endothelial cells in culture.

In the present work we have investigated the binding capacity, to cell membrane of bovine aortic endothelial cells (BAEC) cultured in vitro, of heparan sulfate (M(r) 11.1 kDa) and its four fractions named A (M(r) 24.5 kDa), B (M(r) 10.7 kDa), C (M(r) 9.1 kDa) and D (M(r) 6.8 kDa). Experiments were performed in comparison with unfractionated heparin (M(r) 12.9 kDa). The binding of the examined compounds was determined by the degree of displacement of [3H]-heparin from the cell membrane. The efficiency of heparan sulfate fractions B, C and D in displacing labelled heparin was found to decrease in function with the decrease of the molecular masses of the compounds. [3H]-heparin could be efficiently displaced mainly by heparin and fraction A, the fraction which has the highest molecular weight and represents only 3.8% of the unfractionated HA 90681. These experimental results may confirm that molecular mass is an important feature for the interaction of glycosaminoglycans with the specific binding sites on the cell surface.

Animals↗

Shotgun wounds to the abdomen.

In 1963 Sherman and Parrish (Sherman RT, Parrish RA. Management of shotgun Injuries: A Review of 152 Cases. J Trauma 1963;3:76-86) classified shotgun wounds into three types based upon distance and penetration. Because distances are often unknown, we redefined Sherman's groups by pellet scatter. Type I patients had > 25 cm of scatter, Type II had < 25 cm but > 10 cm, and Type III had < 10 cm. Seventy-one abdominal shotgun wound patients were admitted over 8 years. Eight tangential wounds were managed by local wound care. Of the remaining 63, 27 were Type I, 10 were Type II, and 26 Type III. Two Type II and six Type III patients died within 24 hours. All required laparotomy. Nine of the Type I patients required laparotomy; eight had peritoneal signs and one had progressive abdominal tenderness, hypotension, and intra-abdominal pellets. Eighteen Type I patients without peritoneal signs were observed without complications. Type III patients suffered more vascular injuries and presented more frequently with hypotension than Type II patients. Of the patients surviving greater than 24 hours, Type IIIs received more transfusions and stayed longer in the intensive care unit and hospital than Type IIs. They also suffered more complications than Type IIs. Seven Type III patients required complicated reconstruction of the abdominal wall. Classification of abdominal shotgun injuries using pellet spread is a more useful system in determining patient management and prognosis compared to systems based on distance. Type II and III abdominal shotgun injuries require laparotomy, debridement of soft tissue injuries and frequently reconstruction of abdominal wall defects. Type I injuries can be managed effectively using signs of peritoneal irritation or progressive abdominal tenderness as the best indicator of the need for operation.

Abdominal Injuries↗

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.

Abdominal Injuries↗

Correlation of abdominal trauma index and injury severity score with abdominal septic complications in penetrating and blunt trauma.

The Abdominal Trauma Index (ATI) was designed to stratify patients with penetrating injuries, and has been used to classify patients with blunt trauma. The Injury Severity Score (ISS) was originally designed to stratify victims of blunt trauma, and it has also been used for victims of penetrating trauma. We attempted to validate the use of ISS and ATI for both penetrating and blunt trauma. A total of 592 penetrating and 334 blunt trauma patients who underwent laparotomy over a 5-year period were evaluated. The overall rate of abdominal sepsis was 7.5% for blunt trauma and 7.6% for penetrating trauma. Mortality (excluding deaths within 48 hours) was 7% for blunt trauma and 1% for penetrating trauma. In the penetrating injury population, an ATI value greater than 15 and an ATI value greater than 25 were significantly associated with abdominal septic complications (ASCs) (p less than 0.001, both comparisons). An ISS greater than or equal to 16 was also associated with ASCs (p less than 0.001). The ASC rate for gunshots was higher than that for stab wounds (11% vs. 2%; p less than 0.001). In the blunt group, an ATI value greater than 15 and an ATI value greater than 25 were associated with ASCs (p less than 0.01 and p less than 0.001, respectively). The association of ASCs and ISS was linear with increasing ISS in patients with blunt abdominal trauma.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Injuries↗

Aortoiliac reconstruction following penetrating injury.

In summary, there are several factors essential to successful treatment of major vascular abdominal injuries. Prompt resuscitation and abdominal exploration is paramount. Proximal control can quickly be obtained at the esophageal hiatus and adequate exposure of the retroperitoneum is mandatory. Most aortic injuries can be repaired primarily; however, if an arterial substitute is necessary, then PTFE is the substitute of choice. Reimplantation of the injured iliac artery to the contralateral iliac artery is an option for bifurcation injuries if that will not inordinately constrict the lumen. And finally, four-compartment fasciotomies will decompress the lower extremities and prevent ischemic muscle necrosis following reperfusion injury.

Adolescent↗

Duration of antibiotic therapy for penetrating abdominal trauma: a prospective trial.

BACKGROUND: The optimal duration of antibiotic use in penetrating abdominal trauma is incompletely defined. It is generally accepted that short-term antibiotics are appropriate for low-risk wounds. However, with colon injury and significant degree of injury, abdominal trauma index (ATI) more than 25, concern exists that short-term treatment is not adequate. METHODS: The study was a prospective double-blind trial of 24-hour treatment (cefoxitin or cefotetan) compared with 5-day treatment in 515 patients. Major abdominal infections (MAI) included abscess, necrotizing fasciitis, and diffuse peritonitis. RESULTS: MAI occurred in 8% of those patients with 1-day therapy and 10% with 5-day therapy. Subgroup analysis of high-risk groups (colon wounds and ATI of more than 25) showed the following MAI rates: colon, 1-day therapy, 14%; 5-day therapy, 15%; ATI of more than 25, 1-day therapy, 17%; 5-day therapy, 30%. CONCLUSIONS: Regardless of contamination and degree of injury, 24-hour antibiotic therapy is satisfactory for all penetrating abdominal trauma.

Abdominal Injuries↗

Laryngotracheal trauma.

Laryngotracheal trauma (LTT) is a rare but clinically important injury that may be missed without a high index of suspicion. Forty patients with LTT admitted to the University of Tennessee, Memphis from 1984 through 1989 were retrospectively reviewed. Twenty-six patients sustained penetrating (P)-LTT and 14 had blunt (B)-LTT. Three patients with P-LTT and one with B-LTT arrived in full arrest. Sixty-five per cent of blunt injuries, and 100 per cent of penetrating injuries had neck tenderness or overlying evidence of trauma. A combination of angiography, barium swallow, esophagoscopy, CT scan, bronchoscopy and/or laryngoscopy was used for evaluation, depending on the mechanism. Twenty-two of the 23 surviving P-LTT patients underwent surgery; 11 (50%) had concomitant esophageal injury. All patients with complications from P-LTT were in the group with esophageal injury. B-LTT was classified as either mild5, moderate3, or severe6; all 6 severely injured patients had preoperative airway compromise. All complications of B-LTT occurred in the severely injured group. The following conclusions were reached: LTT usually presents with symptoms and/or signs, but they may be minimal and nonspecific. Emergency tracheostomy should not be delayed if ventilation is compromised. Concomitant esophageal injuries are frequent in P-LTT and predispose the patient to postoperative complications. Airway compromise frequently correlates with severity of injury in B-LTT and these patients are also at high risk for complications.

Emergencies↗

Factors affecting morbidity following hepatic trauma. A prospective analysis of 482 injuries.

During a 5-year period, 482 patients with liver injuries were studied prospectively: 65% resulted from penetrating and 35% from blunt injuries. The injuries were graded by the hepatic injury scale (grades I to VI); transfusion requirements and perihepatic abscesses correlated with increasing scores. Minor surgical techniques were needed in 338 patients and 144 patients required major techniques. Omental packing was used in 60% of the major injuries and yielded 7% mortality and 8% abscess rates. Gauze packs were used for management of 10% of major injuries and yielded 29% mortality and 30% abscess rates. The patients were randomized to no drain, closed suction, or sump drainage and respective perihepatic abscess rates were 6.7%, 3.5%, and 13% (p less than 0.03; suction compared to closed suction). Multivariate analysis demonstrated increasing abdominal trauma indices and transfusion requirements as well as sump drainage to be associated independently with perihepatic infection.

Adolescent↗