Search

Introduction: The necessity of angioembolization for all splenic pseudoaneurysms (PSAs) is unknown after blunt trauma. We compared the outcomes of patients with PSAs managed with splenic artery embolization (EMBO) versus no embolization (NO-EMBO)., Methods: We retrospectively reviewed all patients with blunt splenic trauma and PSA on initial computed tomography scan admitted to an academic, urban, Level I trauma center from 2016 to 2021. Patients who had emergent splenectomy or died before discharge were excluded. Demographics, injury and computed tomography characteristics, and details regarding angiography, if pursued, were collected. The primary outcome was failure of nonoperative management (FNOM), as defined by need for delayed splenectomy for the EMBO group versus delayed splenectomy or embolization for the NO-EMBO group., Results: One hundred and fifty-six patients were in the final study population, of which 96 (61.5%) were in the EMBO group and 60 (38.5%) were in the NO-EMBO group. Patient demographics and mechanism of injury were similar between the two cohorts. The two cohorts had similar imaging findings, however, EMBO patients had more compartments with hemoperitoneum (2 versus 1, P < 0.01). Patients who underwent embolization had a lower FNOM rate (3.1% versus 13.3%, P = 0.02)., Conclusions: Splenic artery embolization in the setting of PSA is associated with lower rates of FNOM versus nonembolization. It is unclear if addressing the PSA itself with embolization drives the decreased FNOM rate., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Introduction: Obesity is associated with higher mortality following trauma, although the pathogenesis is unclear. Both obesity and trauma are associated with syndecan-1 shedding and metalloproteinase-9 (MMP-9) activation, which can adversely affect endothelial cell function. We recently demonstrated that fibrinogen stabilizes endothelial cell surface syndecan-1 to reduce shedding and maintain endothelial barrier integrity. We thus hypothesized that MMP-9 activation and syndecan-1 shedding would be exacerbated by obesity after trauma but attenuated by fibrinogen-based resuscitation., Materials and Methods: ApoE null ( -/- ) mice were fed a Western diet to induce obesity. Mice were subjected to hemorrhage shock and laparotomy then resuscitated with Lactated Ranger's (LR) or LR containing fibrinogen and compared to null and lean sham wild type mice. Mean arterial pressure (MAP) was monitored. Bronchial alveolar lavage protein as an indicator of permeability and lung histopathologic injury were assessed. Syndecan-1 protein and active MMP-9 protein were measured., Results: MAP was similar between lean sham and ApoE -/- sham mice. However, following hemorrhage, ApoE -/- mice resuscitated with fibrinogen had significantly higher MAP than LR mice. Lung histopathologic injury and permeability were increased in LR compared to fibrinogen resuscitated animals. Compared with lean sham mice, both active MMP-9 and cleaved syndecan-1 level were significantly higher in ApoE -/- sham mice. Resuscitation with fibrinogen but not lactated Ringers largely reduced these changes., Conclusions: Fibrinogen as a resuscitative adjunct in ApoE -/- mice after hemorrhage shock augmented MAP and reduced histopathologic injury and lung permeability, suggesting fibrinogen protects the endothelium by inhibiting MMP-9-mediated syndecan-1 cleavage in obese mice., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Nutritional supplementation has become the standard of care for management of critically ill patients. Traditionally, nutritional support in this patient population was intended to replete substrate deficiencies secondary to stress-induced catabolism. Recognition of the influence of certain nutrients on the immune and inflammatory response of the critically ill has led to the evolution of more sophisticated nutritional strategies and concepts. Administration of immune-enhancing formulas supplemented with a combination of glutamine, arginine, omega-3 fatty acids (omega-3 FA), and nucleotides have been shown in most studies to reduce infectious outcomes. More recently, the separation of nutritional support from the provision of key nutrients has led to a further appreciation of the immunomodulatory and anti-inflammatory benefits of isolated nutrients, such as glutamine and antioxidants. The purpose of this article is to review the molecular mechanisms that are unique to each class of frequently utilized nutrients. A better understanding of the specific molecular targets of immunonutrients will facilitate application of more refined nutritional therapies in critically ill patients., (Copyright 2010 Elsevier Inc. All rights reserved.)

Surgical simulation has evolved considerably over the past two decades and now plays a major role in training efforts designed to foster the acquisition of new skills and knowledge outside of the clinical environment. Numerous driving forces have fueled this fundamental change in educational methods, including concerns over patient safety and the need to maximize efficiency within the context of limited work hours and clinical exposure. The importance of simulation has been recognized by the major stake-holders in surgical education, and the Residency Review Committee has mandated that all programs implement skills training curricula in 2008. Numerous issues now face educators who must use these novel training methods. It is important that these individuals have a solid understanding of content, development, research, and implementation aspects regarding simulation. This paper highlights presentations about these topics from a panel of experts convened at the 2008 Academic Surgical Congress.

Background: The passing score for the National Board of Medical Examiner's Surgery Subject Examination (NBME-SS) was raised at an urban academic medical school, resulting in a doubling of the number of students failing their surgical clerkship. We hypothesized that at-risk students could be accurately identified and offered an intense tutorial program to enhance success on their exam., Methods: Preclinical academic records for the graduating class of 2006 were obtained and included gender, ethnicity, preclinical grades, and preclinical NBME's exams, MCAT, and USMLE scores. Simple and multiple linear regression analyses were used to identify correlates with the surgery shelf exam scores and data from the class of 2007 were used for validation., Results: Data were collected on 194 students. On univariate analysis, MCAT, USMLE, and all individual preclinical NBME scores were positively correlated with the NBME-SS (P<0.05). Variables that remained predictive using multiple linear regression were scores on the pathology and physical diagnosis exams (model r(2)=0.48). The single strongest predictor of failure was performance on the pathology shelf exam (ROC area was 0.85 with P<0.0001), which also held true for the class of 2007., Conclusions: There is a strong correlation between poor performance on the third-year NBME-SS and the second-year pathology NBME scores. The reason for this correlation is unclear but may be related to the integrative thinking and clinical application skills requisite for surgical decision-making first required by preclinical students during their pathology course. Whether efforts to assist medical students with this skill set will be effective warrants further study.

Background: The purpose of the present study was to determine how preclinical medical students formulate their career choice and to determine the origin of negative perceptions regarding surgery as a career., Materials and Methods: A qualitative study was performed with second-year medical students voluntarily participating in focus group study. Students with and without an interest in surgery attended. Topics discussed included factors influencing career choice, priorities, perceptions, exposure, and interactions with surgeons. Three investigators conducted independent content analysis., Results: Career choices for students interested in surgery originated primarily from premedical school experiences/interactions with surgeons. In contrast, students not interested in surgery made career choices during medical school and choices were shaped primarily by second-year preceptors. The main priority for students interested in surgery was personal happiness that was perceived as being significantly dependent upon career satisfaction. Students not interested in surgery tended to separate happiness derived from career versus family. Negative perceptions toward surgery were developed and reinforced by media, preceptors, and classmates. All students had minimal exposure to surgeons during preclinical years and generally agreed that increased involvement with surgeons would be beneficial, particularly through preclinical preceptorships., Conclusions: Career choices of preclinical students interested in surgery were made prior to entering medical school, suggesting that outreach programs to high schools and colleges may beneficial. Negative perceptions about surgery develop through a variety of sources, including fellow classmates, preceptors, and the media. Surgeons need to take responsibility for these perceptions.

Background: We have shown that both intraischemic hypothermia and hypertonic saline resuscitation provide dramatic protection against gut ischemia/reperfusion (I/R) injury that is in part mediated by heme oxygenase-1 (HO-1). We therefore hypothesized that induction of HO-1 by hemin would lessen damage and improve function after gut I/R., Materials and Methods: Male Sprague-Dawley rats were treated with 50 micromol/kg hemin (HO-1 inducer ferric protoporphyrin IX chloride) sq or vehicle 2 h before superior mesenteric artery occlusion for 60 min or sham laparotomy. After 6 h of reperfusion, transit was determined by quantitation of percentage of tracer in 10 equal segments of small intestine 30 min following injection into the duodenum (expressed as mean geometric center). Ileum was harvested for assessment of mucosal histologic injury (Chiu score 0-5 by blinded observer), myeloperoxidase activity (MPO, index of inflammation), and HO-1 protein expression., Results: Hemin treatment was associated with increased HO-1 protein expression, lessened mucosal injury, decreased MPO activity, and improved intestinal transit following gut I/R., Conclusion: These data corroborate that HO-1 plays an important role in protecting the gut against I/R-induced injury.

Introduction: Superior mesenteric artery occlusion (SMAO) is a simple and reproducible model of shock-induced gut ischemia/reperfusion, but some argue that it is not clinically relevant. The purpose of the current study was to compare SMAO to a standard model of controlled hemorrhage (CH) and uncontrolled hemorrhage (UH)., Methods: Rats had femoral lines and a jejunal mucosal laser Doppler placed followed by SMAO (60 min of ischemia, no resuscitation), controlled hemorrhage (40 mm Hg for 60 min, 2:1 resuscitation shed blood and lactated Ringers), or uncontrolled hemorrhage (liver injury, 3:1 resuscitation with lactated Ringers). Base deficit, lactate, and jejunal mucosal flow (as a percentage of baseline) were recorded during ischemia and for 120 min after reperfusion. Jejunal tissue was harvested for morphological evaluation. Comparison among groups was by analysis of variance (ANOVA), and significance was set at P < 0.05., Results: Mucosal blood flow was similar among groups at the onset of reperfusion (CH, 16.9 +/- 5.0% versus UH, 10.9 +/- 3.1% versus SMAO, 13.9 +/- 6.2%) and during the initial period of reperfusion. By 120 min, however, flow in CH (75.4 +/- 2.5%) was significantly higher that in either UH (36.4 +/- 13.1%) or SMAO (31.7 +/- 8.4%). Histological injury was less with CH, while base deficit was significantly higher in CH at the onset of reperfusion (-24 +/- 2 versus UH, -10 +/- 3 and SMAO, -6 +/- 3 mM/L) but comparable by the end (CH, -17 +/- 4 versus UH, -16 +/- 3 and SMAO, -17 +/- 2 mM/L)., Conclusions: SMAO is a clinically relevant model of shock-induced gut ischemia/reperfusion.

Purpose: Gut ischemia/reperfusion (I/R) elicits an inflammatory response that impairs intestinal transit. We have previously shown that regional intraischemic hypothermia (IH) protects against moderate gut I/R-induced mucosal injury, is associated with decreased NF-kappaB activity and inducible nitric oxide synthase induction and preserves heme oxygenase-1 (HO-1) expression. HO-1 provides cytoprotection in various models of oxidant stress. We, therefore, tested the hypothesis that IH protects against gut I/R-induced impaired intestinal transit via HO-1 induction., Materials and Methods: At laparotomy (lap), Sprague-Dawley rats had duodenal catheters placed followed by sham or gut I/R (superior mesenteric artery occlusion for 75 min) with or without regional IH (15 degrees C). Each animal was placed on a heating blanket maintaining systemic normothermia (37 degrees C). At 12 or 24 h of reperfusion, small intestinal transit was determined by quantitating the distribution of a tracer (FITC dextran) in the intestine 30 min after instillation (expressed as geometric center of distribution). Ileal samples were obtained for histology and HO-1 expression, assessed by Western immunoblot at 12 and 24 h of reperfusion. In separate experiments, rats were pretreated with an HO-1 inhibitor Sn protoporphyrin IX (25 mumol/kg, ip), 1 h before superior mesenteric artery occlusion and transit measured as above., Results: Rats treated with I/R had increased histological injury and impaired intestinal transit at both 12 and 24 h compared with sham. Rats treated with I/R+IH exhibited histological injury and transit comparable with sham controls. I/R induced HO-1 expression at 12 and 24 h of reperfusion and IH augmented this I/R-induced HO-1 expression. Sn protoporphyrin IX abrogated IH protection against histological injury and impaired transit., Conclusion: We conclude that intraischemic regional hypothermia protects against histological injury and impaired intestinal transit caused by severe gut I/R injury. Hypothermic protection under these conditions is in part due to HO-1 expression.

Background: General surgery training programs are experiencing an alarming decrease in applicants. The purpose of the current study was to determine whether exposing students to surgery through a brief intervention early in their medical education could influence perceptions toward surgery as a career choice., Methods: First-year medical students were asked to rank 19 items coded on a Likert-type scale from 1 (not important) to 8 (very important) regarding their beliefs about surgery as a career both before and after a brief 1-h intervention with a panel of surgeons. Each panelist spoke about his or her professional and personal lives, followed by a question and answer period. Survey data were analyzed by Wilcoxon sign-rank and Spearman rank correlation., Results: Of 210 first year students, 121 (58%) students voluntarily attended and completed the presurvey and 94 (45%) the post, of which 82 were matched responses. Preintervention responses revealed that career opportunities, intellectual challenge, and the ability to obtain a residency position were positively correlated with surgery (P < 0.007) whereas length of training, lifestyle during residency, lifestyle after training, and work hours during residency were negatively correlated (P < 0.01). The following factors were significantly influenced by the intervention: academic opportunities, patient relationships, prestige, and gender distribution became more important whereas concern about debt and length of training became less important., Conclusions: Positive encounters with surgeons can favorably influence the perceptions of first-year medical students toward a career in surgery. In addition to addressing lifestyle issues, surgeons can and must make a concerted effort to interact with medical students early in their education and foster their interest throughout their career.

Background: Postinjury enteral nutrition (EN) is beneficial. Unfortunately, severely injured patients who should benefit most are frequently intolerant. To assist in maximizing enteral tolerance in the critically injured, we first implemented a prospective analysis of the effectiveness of a standardized enteral protocol (EP) at a single institution followed by a prospective multi-institutional analysis of its implementation., Methods: Tolerance parameters were prospectively collected on severely injured patients at a single (Phase I) and then multiple (Phase II) institutions. EN was begun at 15 cc/h and advanced every 12 h to a patient specific targeted goal. Intolerance symptoms (high nasogastric output/emesis, abdominal distention, and diarrhea) were assessed and graded every 12 h and managed using a standardized protocol. Tolerance was characterized as early (during initial advancement of feeds) or late (after standard goal) and classified as good (EN advanced per EP), moderate (rate decreased per EP), poor (EN held per EP), or EN discontinued (and TPN begun)., Results: In Phase I patients (ISS = 25 +/- 3) early tolerance was good in 82% (14/17) while late good tolerance decreased to 65% (11/17). In Phase II patients (ISS = 30 +/- 2), early tolerance was good in 85% (41/49) and late tolerance was good in 80% (39/49). Moderate intolerance was primarily seen in Phase II patients and due to high gastric output in patients fed proximal to the ligament of Treitz (13/16). Overall 88% (15/17) of Phase I and 100% (49/49) of Phase II patients were successfully maintained on EN., Conclusions: Severely injured patients exhibited good tolerance to EN when managed using a standardized protocol at four Level I trauma centers. Moderate intolerance was associated with high gastric output and may be lessened by feeding distal to the ligament of Treitz.

Background: Laparoscopy has been proposed as a diagnostic and potentially therapeutic modality for penetrating diaphragmatic lacerations. The purpose of this study was to assess the technical feasibility and strength of various laparoscopic repairs of diaphragmatic injuries., Methods: Swine underwent either open suture repair or laparoscopic repair by staple, suture, or patch technique of a 2-cm laceration to both the right and the left muscular or tendinous diaphragmatic leaflets. Six weeks after operation, diaphragms were harvested for either histologic analysis or bursting strength measurements., Results: All methods of repair proved technically feasible. There was no significant difference in bursting strength measurements between treatment groups. Bursting was due to tissue failure either at or adjacent to the repair site. Histologic analysis confirmed healing of all specimens with the laparoscopic patch technique inciting less inflammation and greater fibroblastic proliferation than the other techniques., Conclusions: Laparoscopic repair of diaphragmatic lacerations can be accomplished using any of the currently available techniques. Laparoscopic stapling, suturing, or patch techniques all result in complete healing with a strong and durable repair. When selecting a particular technique, familiarity of the surgeon should be used as a guideline., (Copyright 2001 Academic Press.)

Inducible nitric oxide synthase (NOS 2) is thought to play a role in gut motility disorders that occur under proinflammatory conditions. Clinically, ileus occurs after sepsis and shock-induced gut ischemia/reperfusion (I/R). The purpose of this study was to determine if NOS 2 mediates impaired intestinal transit in well-established models of both moderate and severe gut ischemia/reperfusion. At laparotomy, Sprague-Dawley rats had duodenal catheters placed. Small intestinal transit was determined by quantitating the percentage tracer (FITC-dextran) in 10 equal segments of intestine 30 min after catheter injection [expressed as the mean geometric center (MGC) of distribution]. Transit was assessed at 6 and 24 h after gut ischemia [45 or 75 min of superior mesenteric artery occlusion (SMAO) with sham laparotomy as control]. In a separate set of experiments, N(6)-(iminoethyl)-L-lysine (L-NIL), a selective NOS 2 antagonist, was administered 1 h prior to laparotomy and transit was determined after 6 h as described above. Ileal NOS 2 expression was assessed by Western immunoblot and quantitative "real-time" RT-PCR. We observed that both 45 and 75 min of SMAO decreased intestinal transit at 6 h of reperfusion compared to sham. Ileal NOS 2 mRNA and protein were increased after 75, but not 45, min of SMAO. In addition, L-NIL improved transit after 75, but not 45, min of SMAO. We conclude that (1) NOS 2 is upregulated in the gut only after more severe ischemic insults, and (2) ileus is mediated, at least in part, by NOS 2 under these conditions., (Copyright 2001 Academic Press.)

Free radical-induced injury to the arterial wall has been implicated in the pathogenesis and progression of atherosclerosis. To model the in vitro effects of free radicals on endothelial cell function, protein and lipid synthesis were measured after exposing cells to a superoxide generating system of xanthine (X = 100 microM) and xanthine oxidase (XO = 0.2 units). Total protein synthesis, measured by [35S]methionine uptake, decreased by 87.65 +/- 2.04% over 4 hr compared to controls (P < 0.05). Examination of lipid synthesis by high-performance liquid chromatography in cells prelabeled with either [3H]oleic acid or [3H]sodium acetate revealed alterations in all lipid classes. Phospholipid and neutral glyceride synthesis significantly decreased in a time- and dose-dependent fashion compared to controls (two-way ANOVA). In contrast, cholesterol synthesis and lipid peroxidation increased in a time- and dose-dependent fashion. When X = 200 microM and XO = 0.3 units, there was a statistically significant increase in cholesterol synthesis and lipid peroxidation within 24 hr (Tukey's HSD). We conclude that there is evidence of endothelial cell injury as measured by decreases in protein, glyceride, and phospholipid synthesis. The concurrent increases in lipid peroxidation and cholesterol synthesis may explain the relationship between free radical injury and the pathogenesis of atherosclerosis.

Plasma phospholipid binding to cell-derived cholesterol is important in reverse cholesterol transport, a key step in the regression of atherosclerosis. However, the mechanism by which phospholipids are transferred from cells to plasma remains unclear. [3H]Choline-labeled phospholipid efflux from fibroblasts has been studied using plasma and its components as acceptors. The kinetics were resolved into a fast component (k1 = 0.119 +/- 0.23 min-1) that corresponded to high-affinity binding of high-density lipoproteins (HDL) to the cell surface and a slow component (k2 = 0.0047 +/- 0.0009 min-1) due to protein-mediated desorption (n = 3). Altering the donor charge with heparinase or the acceptor charge by acetylation abolished the fast component, while the slow phase was unchanged. Only HDL displayed biexponential kinetics, comparable to whole plasma. Half-lives for low-density lipoprotein and very-low-density lipoprotein were t1/2 = 278 +/- 22 min and t1/2 = 1003 +/- 147 min, respectively. In the absence of transfer factor, HDL alone significantly reduced phospholipid efflux (t1/2 = 663 min). Phospholipid transfer protein restored biexponential kinetics. We conclude that cell membranes are a potentially important source of plasma phospholipids and that protein-mediated transfer to HDL is the major route for cell-to-plasma transfer. This step represents a locus for anti-atherosclerotic intervention.