THE GLOBAL DISTRIBUTION OF ECONOMIC ACTIVITY: NATURE, HISTORY, AND THE ROLE OF TRADE.

We explore the role of natural characteristics in determining the worldwide spatial distribution of economic activity, as proxied by lights at night, observed across 240,000 grid cells. A parsimonious set of 24 physical geography attributes explains 47% of worldwide variation and 35% of within-country variation in lights. We divide geographic characteristics into two groups, those primarily important for agriculture and those primarily important for trade, and confront a puzzle. In examining within-country variation in lights, among countries that developed early, agricultural variables incrementally explain over 6 times as much variation in lights as do trade variables, while among late developing countries the ratio is only about 1.5, even though the latter group is far more dependent on agriculture. Correspondingly, the marginal effects of agricultural variables as a group on lights are larger in absolute value, and those for trade smaller, for early developers than for late developers. We show that this apparent puzzle is explained by persistence and the differential timing of technological shocks in the two sets of countries. For early developers, structural transformation due to rising agricultural productivity began when transport costs were still high, so cities were localized in agricultural regions. When transport costs fell, these agglomerations persisted. In late-developing countries, transport costs fell before structural transformation. To exploit urban scale economies, manufacturing agglomerated in relatively few, often coastal, locations. Consistent with this explanation, countries that developed earlier are more spatially equal in their distribution of education and economic activity than late developers.

Percutaneous Tracheostomy under Bronchoscopic Visualization Does Not Affect Short-Term or Long-Term Complications.

Percutaneous tracheostomy is a safe and effective bedside procedure. Some advocate the use of bronchoscopy during the procedure to reduce the rate of complications. We evaluated our complication rate in trauma patients undergoing percutaneous tracheostomy with and without bronchoscopic guidance to ascertain if there was a difference in the rate of complications. A retrospective review of all tracheostomies performed in critically ill trauma patients was performed using the trauma registry from an urban, Level I Trauma Center. Bronchoscopy assistance was used based on surgeon preference. Standard statistical methodology was used to determine if there was a difference in complication rates for procedures performed with and without the bronchoscope. From January 2007, to April 2016, 649 patients underwent modified percuteaneous tracheostomy; 289 with the aid of a bronchoscope and 360 without. There were no statistically significant differences in any type of complication regardless of utilization of a bronchoscope. The addition of bronchoscopy provides several theoretical benefits when performing percutaneous tracheostomy. Our findings, however, do not demonstrate a statistically significant difference in complications between procedures performed with and without a bronchoscope. Use of the bronchoscope should, therefore, be left to the discretion of the performing physician.

Heterogeneity in Trauma Registry Data Quality: Implications for Regional and National Performance Improvement in Trauma.

BACKGROUND: Led by the American College of Surgeons Trauma Quality Improvement Program, performance improvement efforts have expanded to regional and national levels. The American College of Surgeons Trauma Quality Improvement Program recommends 5 audit filters to identify records with erroneous data, and the Georgia Committee on Trauma instituted standardized audit filter analysis in all Level I and II trauma centers in the state. STUDY DESIGN: Audit filter reports were performed from July 2013 to September 2014. Records were reviewed to determine whether there was erroneous data abstraction. Percent yield was defined as number of errors divided by number of charts captured. RESULTS: Twelve centers submitted complete datasets. During 15 months, 21,115 patient records were subjected to analysis. Audit filter captured 2,901 (14%) records and review yielded 549 (2.5%) records with erroneous data. Audit filter 1 had the highest number of records identified and audit filter 3 had the highest percent yield. Individual center error rates ranged from 0.4% to 5.2%. When comparing quarters 1 and 2 with quarters 4 and 5, there were 7 of 12 centers with substantial decreases in error rates. The most common missed complications were pneumonia, urinary tract infection, and acute renal failure. The most common missed comorbidities were hypertension, diabetes, and substance abuse. CONCLUSIONS: In Georgia, the prevalence of erroneous data in trauma registries varies among centers, leading to heterogeneity in data quality, and suggests that targeted educational opportunities exist at the institutional level. Standardized audit filter assessment improved data quality in the majority of participating centers.

The role of repeat computed tomography scan in the evaluation of blunt bowel injury.

The precise role of repeat abdominal computed tomography (CT) imaging in the diagnosis and management of bowel injury is unclear. We reviewed 540 patients with blunt abdominal trauma managed at a Level II trauma center over a 5-year period to better define the role of repeat imaging. One hundred patients had a repeat abdominal CT scan within 72 hours of admission. These patients were young with multisystem injuries (mean ± standard deviation age, 34 ± 15 years; Injury Severity Score, 21 ± 12; Glasgow Coma Score [GCS], 12 ± 5). There were 14 patients with bowel injuries. All bowel-injured patients survived without abdominal morbidity. Time to repeat CT was shortest in the bowel injured group (20 ± 10 hours). The repeat CT was most helpful in patients with significant closed head injury (mean GCS, 3 ± 1) and in those with occult bowel injury. The repeat scan resulted in a change in clinical management in 26 patients. Regarding the presence of bowel perforation, the follow-up scan enhanced sensitivity from 30 to 82 per cent. The repeat abdominal CT is best used selectively in patients with blunt abdominal trauma and can provide clinically useful information to exclude bowel injury.

Incidence and outcomes of critical illness-related corticosteroid insufficiency in trauma patients.

The spectrum of critical illness-related corticosteroid insufficiency (CIRCI) in trauma is not fully defined. This study describes our trauma experience with hydrocortisone-treated patients experiencing CIRCI. We conducted a 5-year retrospective analysis from a Level II trauma center using biochemical and clinical criteria for adrenal insufficiency. Seventy patients met the inclusion criteria for CIRCI. There was a 34 per cent mortality rate despite therapy. Nonsurvivors were older with larger admission base deficits and experienced higher rates of sepsis, bacteremia, and pneumonia. Nonsurvivors had prolonged vent days (mean 53 ± 64 days) when compared with survivors (mean 30 ± 22 days; P = 0.029). Renal replacement therapy was a strong predictor of mortality. Spinal cord-injured patients had high Injury Severity Scores (mean 34 ± 18), elevated baseline cortisol levels (mean 56 ± 84 vs. 18 ± 14; P = 0.004), and required prolonged duration of steroid therapy (30 ± 52 vs. 15 ± 15 days; P = 0.080) when compared with the nonspinal cord-injured group. Our data suggest that CIRCI in trauma is associated with significant mortality and morbidity even when patients are treated appropriately.

Scout anteroposterior and lateral CT scans as a screening test for thoracolumbar spine injury in blunt trauma.

Anteroposterior and lateral radiographs have traditionally been required to clear the thoracolumbar spine (TLS) after blunt trauma. The routine use of CT scans led to a pilot trial to determine if CT scout images can accurately evaluate the TLS after blunt trauma. The purpose of the study was to determine the sensitivity, specificity, positive and negative predictive values of CT scout images for the evaluation of the TLS. Patients admitted to our level II trauma center requiring CT evaluation of the chest, abdomen, and pelvis were considered for this study. Patients with blunt trauma, without neurologic deficits, or other evidence of spinal trauma on physical examination were included. Charts were reviewed for demographics, scout CT image findings, and full CT scan findings. Scout CT images were compared with reconstructed spine CT scans from chest, abdomen, and pelvis CT scans. Injuries to the TLS were defined as compression fractures, burst fractures, and subluxation. One hundred seventeen patients were included. Average Injury Severity Score was 25.1 (+/-9.4) and average age was 42.5 years. Twenty-three patients had diffuse back tenderness, three had ecchymosis, and 64 had distracting injuries. Twelve injuries to the TLS were present; 11 were seen on scout images. Sensitivity was 92 per cent, specificity 100 per cent, positive predictive value 100 per cent, and negative predictive value 99 per cent. Scout CT images provide an accurate assessment of the TLS after blunt trauma. We are encouraged by the results and will continue to investigate to identify the criteria that allow scout CT images to safely replace anteroposterior and lateral radiographs in the evaluation of the TLS in blunt trauma.

Retrievable inferior vena cava filters: initial clinical results.

Anticoagulation is the accepted therapy for patients with thromboembolic disease. When contraindications to anticoagulant therapy are present, however, interruption of the inferior vena cava (IVC) may prevent pulmonary embolism (PE). The objective of this study was to report our early technical and clinical results with retrievable IVC filters (IVCFs) for the prevention of PE. One hundred and twenty-seven multitrauma patients between December 1, 2002, and December 31, 2004, underwent placement of Gunther-Tulip (n = 49), Recovery (n = 41), or OptEase (n = 37) retrievable IVCFs under real-time intravascular ultrasound (IVUS) guidance. All patients had abdominal X-rays to verify filter location. Prior to IVCF retrieval, all patients underwent femoral vein color flow ultrasonography to rule out deep vein thrombosis (DVT) and vena-cavography to assess the IVCF for trapped emboli, filter tilt, or retrained thrombus. Thirty-nine patients died of their injuries; no deaths were related to IVCF placement. One PE occurred during follow-up after filter retrieval, and two femoral vein insertion-site DVTs occurred. One hundred twenty (94.4%) of IVCFs were placed without complication at the L2-3 level, as verified by abdominal X-rays. Filter-related complications included three groin hematomas (2.9%) and three IVCFs misplaced in the right iliac vein early in our experience (2.3%); these filters were uneventfully retrieved and replaced in the IVC within 24 hr. Sixty-six patients underwent uneventful retrieval of IVCFs after DVT or PE anticoagulation prophylaxis was initiated. Forty-five IVCFs were not removed: 41 due to contraindications due to anticoagulation and four because of trapped thrombus within the filter. The role of retrievable IVCFs continues to evolve, but in this study of 127 patients, prophylactic temporary IVCF placement was simple and safe, prevented fatal PE, and served as an effective "bridge" to anticoagulation. Further investigation of this bedside IVUS technique and the role of temporary IVCFs in different patient populations is warranted.

Role of prophylactic temporary inferior vena cava filters placed at the ICU bedside under intravascular ultrasound guidance in patients with multiple trauma.

OBJECTIVE: Patients with multiple trauma often have injuries that preclude the use of anticoagulation therapy or sequential compression device prophylaxis. Temporary inferior vena cava (IVC) filters (IVCFs) offer protection against pulmonary embolism during the early immediate injury and perioperative period, when risk is highest, while averting potential long-term sequelae of permanent IVCFs. The objective of this study was to evaluate the efficacy of prophylactic, temporary IVCF placement at the intensive care unit bedside under real-time intravascular ultrasound (IVUS) guidance in patients with multiple trauma. INTERVENTIONS: Ninety-four patients with multiple trauma seen between July 1, 2002, and November 1, 2003, underwent placement of OptEase (Cordis Endovascular) retrievable IVCFs under real-time IVUS guidance. Mean (+/-SD) Injury Severity Score was 25.1 +/- 2.2). Abdominal x-ray films were obtained in all patients to verify filter location. Before IVCF retrieval all patients underwent femoral vein color-flow ultrasound scanning to rule out deep vein thrombosis (DVT), and pre-procedure and post-procedure vena cavography to identify possible IVCF thrombus entrapment and post-retrieval inferior vena cava injury. RESULTS: Nineteen patients died of their injuries; no deaths were related to IVCF placement. One pulmonary embolism occurred during follow-up after filter retrieval, and 1 insertion site femoral vein DVT occurred. As verified on abdominal x-ray films, 96.8% (91 of 94) of IVCFs were placed without complications at the L2-3 level. Filter-related complications included 2 groin hematomas (2.1%) and 3 IVCFs misplaced in the right iliac vein (3.2%), early in our experience; the filters were uneventfully retrieved and replaced in the inferior vena cava within 24 hours. Thirty-one patients underwent uneventful retrieval of IVCFs after DVT or pulmonary embolism anticoagulation prophylaxis was initiated. Forty-four filters were not removed, 41 because severity of injury prevented DVT or pulmonary embolism prophylaxis and 3 because of thrombus trapped within the filter. CONCLUSIONS: Prophylactic, temporary IVCF placement at the intensive care unit bedside under IVUS guidance in patients with multiple trauma is simple and safe, and serves as an effective "bridge" to anticoagulation therapy until venous thromboembolism prophylaxis can be initiated. Further investigation of this bedside technique and the role of temporary IVCFs in patients with multiple trauma is warranted. CLINICAL RELEVANCE: Patients with multiple trauma often have injuries that preclude the use of anticoagulation therapy or sequential compression device prophylaxis. Temporary inferior vena cava filters (IVCFs) offer protection against pulmonary embolism during the perioperative and immediate injury period, when risk is highest. Ninety-four patients with multiple trauma underwent prophylactic, temporary IVCF placement at the intensive care unit bedside under real-time intravascular ultrasound. One pulmonary embolism occurred during follow-up after filter retrieval, and 1 insertion site femoral vein deep venous thrombosis occurred. Ninety-one of 94 IVCFs (96.8%) were placed without complication. Thirty-one patients underwent uneventful retrieval of IVCFs after anticoagulation prophylaxis was initiated. Forty-four filters were not removed, because of severity of injury (n = 41) or because of trapped thrombus within the filter (n = 3). Prophylactic, temporary IVCFs placed under intravascular ultrasound guidance at the bedside in patients with multiple trauma is simple, safe, and an effective bridge to anticoagulation therapy.

Primary duodenal low-grade mucosa-associated lymphoid tissue lymphoma presenting with outlet obstruction.

Low-grade lymphoma arising in mucosa-associated lymphoid tissue (MALT) of the duodenum represents a very rare neoplasm. We report an unusual presentation of primary duodenal MALT lymphoma in a 78-year-old man. The patient initially presented with a suspected pulmonary embolus and was anticoagulated, which precipitated a major gastrointestinal hemorrhage. A large atypical ulcer with narrowing of the duodenum beyond the bulb was seen on endoscopy. Biopsies revealed atypical lymphoid cells. Abdominal CT scan revealed a mass in either the duodenum or head of the pancreas. An endoscopic retrograde cholangiopancreatography (ERCP) was performed, which revealed a normal pancreatic duct with a large calculus in the common bile duct, which was extracted after sphincterotomy. Elective surgery was planned for suspected lymphoma of the duodenum. The patient developed severe nausea, vomiting, and fullness after meals. The patient underwent pancreaticoduodectomy for a neoplastic mass causing duodenal obstruction. Pathological examination of the resected specimen revealed a low-grade B-cell lymphoma (MALToma) arising in the duodenum and invading the pancreas. Flow cytometry confirmed the phenotype typical of MALT lymphoma. Celiac, peripancreatic, pelvic, and cervical nodes were also involved with tumor. Bone marrow was also positive for metastasis. The patient was postoperatively treated with chemotherapy for stage IV disease.

Real-time intravascular ultrasound-guided placement of a removable inferior vena cava filter.

BACKGROUND: Reports have demonstrated the benefit of prophylactic inferior vena cava filter (IVCF) placement to prevent pulmonary embolism. This series evaluates the potential for the bedside placement of a removable IVCF under "real-time" intravascular ultrasound (IVUS) guidance. METHODS: Twenty trauma patients underwent intensive care unit placement of a removable IVCF with IVUS guidance. All patients had ultrasonography of the femoral veins after placement to rule out postprocedure femoral vein thrombosis and radiographs to identify filter location. RESULTS: Nineteen of 20 IVCFs were placed at approximately the L2 level as verified by radiography. One patient had a large IVC (34 mm) and underwent bilateral common iliac IVCF placement under IVUS. Within 3 weeks of placement, 12 IVCFs were retrieved. Of the remaining eight patients, six had indications for permanent implantation, two had contralateral deep venous thrombosis, and one had ipsilateral deep venous thrombosis. CONCLUSION: Bedside insertion of a removable IVCF with IVUS guidance and its removal are simple, safe, and accurate.

Multiple myeloma in a patient with hoarseness, dysphagia, aspiration, and cervical lymphadenopathy.

Multiple myeloma, which primarily affects the elderly, is rare in the head and neck. We report the case of a 71-year-old man who came to us with hoarseness, dysphagia, intermittent aspiration, and cervical lymphadenopathy. Our work-up included laboratory tests, radiographic examinations, analysis of bone marrow aspiration, and histopathologic evaluations. Cervical lymph node biopsy confirmed a diagnosis of multiple myeloma. Despite treatment with chemotherapy and radiation, the patient died of his disease 6 months later.

Retrohepatic vena cava and hepatic vein injuries: a simplified experimental methods of treatment by balloon shunt.

BACKGROUND: Fecal contamination from colon injury has been thought to be the most significant factor for the development of surgical site infection (SSI) after trauma. However, there are increasing data to suggest that other factors may play a role in the development of postinjury infection in patients after colon injury. The purpose of this study was to determine the impact of gastric wounding on the development of SSI and nonsurgical site infection (NSSI) in patients with colon injury. METHODS: Post hoc analysis was performed on data prospectively collected for 317 patients presenting with penetrating hollow viscus injury. One hundred sixty-two patients with colon injury were subdivided into one of three groups: patients with isolated colon wounds (C), patients with colon and stomach wounds with or without other organ injury (C+S), and patients with colon and other organ injury but no stomach injury (C-S) and assessed for the development of SSI and NSSI. Infection rates were also determined for patients who sustained isolated gastric injury (S) and gastric injury in combination with organ injuries other than colon (S-C). Penetrating Abdominal Trauma Index, operative times, and transfusion were assessed. Discrete variables were analyzed by Cochran-Mantel-Haenszel chi2 test and Fisher's exact test. Risk factor analysis was performed by multivariate logistic regression. RESULTS: C+S patients had a higher rate of SSI infection (31%) than C patients (3.6%) (p = 0.008) and C-S patients (13%) (p = 0.021). Similarly, the incidence of NSSI was also significantly greater in the C+S group (37%) compared with the C patients (7.5%) (p = 0.07) and the C-S patients (17%) (p = 0.019). There was no difference in the rate of SSI or NSSI between the C and C-S groups (p = 0.3 and p = 0.24, respectively). The rate of SSI was significantly greater in the C+S patients when compared with the S-C patients (31% vs. 10%, p = 0.008), but there was no statistical difference in the rate of NSSI in the C+S group and the S-C group (37% vs. 24%, p = 0.15). CONCLUSION: The addition of a gastric injury to a colon injury has a synergistic effect on the rate of postoperative infection.

Malignant duodenal somatostatinoma presenting in association with von Recklinghausen disease.

Somatostatinomas are extremely rare periampullary malignant neuroendocrine tumors that may be associated with von Recklinghausen disease or type-I neurofibromatosis. Duodenal somatostatinomas are distinguished from pancreatic somatostatinomas by their frequent association with type-I neurofibromatosis and typically absence of somatostatinoma syndrome. We report a very rare and atypical case of malignant duodenal somatostatinoma presenting with somatostatinoma syndrome in association with type-I neurofibromatosis.

Relationship of the tubular system with other organelles in chlorride cells of the channel catfish, Ictalurus punctatus.

The morphology of chloride cells in the channel catfish, Ictalurus punctatus, has been studied by transmission electron microscopy. The chloride cell possesses abundant tubules, mitochondria, and granules. The employment of a special membrane stain in conjunction with a two- or tridimensional analysis reveals a complex interjoining and interlocking ring system of tubules. Tubular sides constituting the complex rings frequently lack granules. The tubular rings join with tubulous mitochondrial profiles and other cytoplasmic components. © 1995 Wiley-Liss, Inc.

Developmental events of the pectoral muscle in rainbow trout larvae (Salmo gairdneri).

Skeletal muscles of developing pectoral fins in rainbow trout larvae (Salmo gairdneri) were analyzed by electron microscopy. Large, branched mitochondria were dominant structures in developing myotubes. Mitochondria were associated with the tubular system (T and SR). New mitochondria arose from old ones when the latter extruded whorls of paired membranes surrounding a nonmembranous core. The core was comprised in part of a dense material, presumably, DNA. The developing muscles were characterized by two sets of caveolae which provided the major contributions to the tubular system. Large caveolae gave rise to elements traditionally designated as SR tubules but which later lost their exterior connections. Small caveolae gave rise to small diameter tubules that appear to be analogous to T tubules, which maintained connections with the exterior. Both tubular elements abutted mitochondria. The two elements ran parallel to each other and intersected with each other to form junctions. Each set of elements possessed intratubular junctions.

Scanning electron microscopy of the air bladder in the spotted gar, Lepisosteus occulatus.

The surface of the gar respiratory epithelium was examined by scanning electron microscopy. Nonciliated and ciliated cells constitute the epithelium. Puffs appear to be an unusual feature of the ciliated cells as well as nonciliated cells. There appears to be a transition from nonciliated to puff ciliated cells through a puff stage. The role of the cell types as related to oxygen available in the air bladder is discussed.