Analysis of driving simulator performance for post-call orthopaedic surgery residents.

PURPOSE: Despite the associations between workhours, fatigue and motor vehicle accidents, driving abilities for residents post-call have been infrequently analysed. Our purpose was to compare orthopaedic surgery resident performance on a driving simulator after a night of call compared with their baseline. STUDY DESIGN: All residents from a single orthopaedic programme were asked to complete baseline and post-call driving simulator assessments and surveys. The primary outcome measure was brake reaction time (BRT) and secondary outcome measures included lane variance, speed variance and accidents on the driving simulator. RESULTS: All 19 orthopaedic residents agreed to participate. Compared with the baseline assessment, residents demonstrated significantly higher levels of sleepiness on the Stanford Sleepiness Scale post-call (1.6 vs 3.4; p<0.0001). Despite higher levels of fatigue post-call, there was no statistically significant differences between baseline and post-call assessments for mean BRT, accidents, lane variation and speed variation. CONCLUSIONS: These data suggest that for orthopaedic residents, driving simulator performance does not appear to be worse after a single night of call compared with baseline. Future collaborative, multicentre investigations on post-call driving safety that incorporate different call types and frequencies are necessary to better define the impact of post-call fatigue on driving performance. Recognising that motor vehicle accidents remain the leading cause of death for people under the age of 30 years, these continued areas of study are necessary to truly establish a culture of resident safety.

Injuries in the competitive paediatric motocross athlete.

PURPOSE: The purpose of this study is to report the spectrum of injuries sustained by competitive paediatric motocross athletes at a level I trauma centre. PATIENTS AND METHODS: A retrospective study of paediatric competitive motocross injuries treated at a level I trauma centre between 2004 and 2014 was performed. Athletes were included if aged less than 18 years and injured while practising or competing on a competitive motocross track. Medical records were reviewed for age, gender, race, location of accident, use of safety equipment, mechanism of injury, injury type and severity, Glasgow Coma Score at hospital presentation and Injury Severity Score (ISS). RESULTS: In total, 35 athletes were studied. The average age was 14 years. One athlete died. Thirty athletes were injured during competition; five were injured during practice. Twenty-four athletes (69%) suffered an orthopaedic injury with a total of 32 fractures and two dislocations. Two fractures were open (6.3%). Lower extremity fractures were twice as common as upper extremity fractures. Surgery was more common for lower extremity fractures-83% versus 30%. The most common fractures were femoral shaft (18.8%), fibula (12.5%), clavicle (12.5%), tibial shaft (9.4%) and forearm (9.4%). CONCLUSIONS: Competitive paediatric motocross athletes suffer serious, potentially life-threatening injuries despite the required use of protective safety equipment. Femoral shaft, fibula and clavicle were found to be the most commonly fractured bones. Further prospective research into track regulations, protective equipment and course design may reduce the trauma burden in this athlete population.

Observer performance studies: detection of single versus multiple abnormalities of the chest.

OBJECTIVE: We used receiver operating characteristic (ROC) analysis to compare two methods of evaluating observer performance in detecting an abnormality on chest radiographs. In the first method, the abnormality in question, rib fracture, was one of five investigated, and it was the only one of interest in the second. MATERIALS AND METHODS: Eight experienced observers viewed 117 posteroanterior chest radiographs in two interpretation modes. Fifty-four of these images depicted rib fractures that had been rated as subtle for detection. The likelihood of the presence of a rib fracture was rated as one of five abnormalities in question in one mode and the sole abnormality of interest in the other mode. RESULTS: Six of the observers performed better during the single-abnormality mode, one performed equally well in both modes, and one performed better during the multiple-abnormality mode. The average area under the ROC curves (A(z)) was 0.73 +/- 0.07 for the multiple-abnormality mode and 0.80 +/- 0.04 for the single-abnormality mode. The results were significantly different (p < 0.05). CONCLUSION: Study methodology can significantly affect the results in ROC studies, particularly for abnormalities that may not be perceived as primary or important. The order in which abnormalities appear on a checklist report form may be important.

CT features of pulmonary alveolar proteinosis.

OBJECTIVE: This investigation describes the CT features of pulmonary alveolar proteinosis in a large group of patients. MATERIALS AND METHODS: A retrospective review of 139 chest CT scans (79 thick-section scans and 60 thin-section scans) from 27 patients with pathologically proven pulmonary alveolar proteinosis was performed. Two independent observers assessed the intraslice patterns and zonal distribution of disease on three CT images of each lung. The observers also graded the percentage of ground-glass opacities, air-space opacities, fibrosis, interlobular opacities, intralobular opacities, and emphysema in each slice. CT scans obtained before and after lavage related to 12 whole-lung lavage treatments on nine patients were evaluated. RESULTS: The dominant intraslice pattern was geographic, but a diffuse pattern was sometimes seen. The most common zonal pattern was uniform; a lower zone predominance was next most frequent. Ground-glass, air-space, and fibrotic opacities had a generally homogeneous craniocaudal distribution, but there was a trend toward more interlobular opacities at the lung bases (p < 0.002). Ground-glass opacities were seen on at least one scan in 100% of the patients. Interlobular opacities (85%), air-space opacities (78%), substantial fibrosis (7%), and intralobular opacities (7%) occurred less frequently. Compared with thick-section images, thin-section images showed more interlobular opacities, but no difference in ground-glass, air-space, or fibrotic disease. The proportion of lung affected by ground-glass and interlobular opacities decreased significantly (p < 0.05) after lavage. CONCLUSION: Pulmonary alveolar proteinosis does not present only with alveolar disease. The CT appearance typically combines different types of opacities with a geographic pattern and a uniform zonal distribution with variation over time.

Multipoint rank-order study methodology: observer issues.

RATIONALE AND OBJECTIVES: We performed a multipoint rank-order experiment to evaluate variability in observers' sensitivity to small differences in image presentation and to assess observers' performance as a function of the type and number of tasks included. METHODS: Five experienced observers were presented with four sets of chest images that had been compressed at five different levels. Each set contained six images ranging from noncompressed to approximately 60:1-compressed images. Observers were asked to review all images of each case side by side and rank-order the "quality" of each to enable determination of the presence or absence of interstitial disease and/or pneumothoraces. RESULTS: Observers varied significantly in their ability to detect very small differences among the images (P < 0.001). Those who performed well did so regardless of whether they ranked a specific abnormality in a multidisease or a single-disease setting. CONCLUSIONS: Selected observers can reliably detect very small differences among similar images. These readers could be used to confirm or rule out the need for objective observer-performance-type studies.

Effect of calcitriol and pamidronate in multiple myeloma.

Addition of bisphosphonates to standard treatment of multiple myeloma (MM) decreases bone pain and skeletal events without influencing bone healing. Calcitriol, besides its established effects on bone remodeling and calcium metabolism, has both immunoregulatory and cell differentiating effects in vitro and in vivo. Moreover, low serum calcitriol has been reported in MM. We tested the effects of supportive treatment with calcitriol and pamidronate on bone disease in two stage-III-B MM patients with diffuse bone involvement, normal serum calcium, and low serum calcitriol. Complete blood counts, serum calcium, creatinine, quantitative serum and urine immunoglobulins, and biochemical indices of bone turnover, serum calcidiol, calcitriol, parathyroid hormone, skeletal radiographs, and bone mineral density by dual x-ray absorbtiometry were measured every 1-6 months for 16 months in the first patient and 7 months in the second patient. Both patients showed a dramatic improvement of MM activity and in bone disease documented by serial radiographs in the first patient and by increased bone mineral density (approximately 15%) in the second. The reduced serum calcitriol in both patients and the elevated parathyroid hormone observed in the first patient before treatment returned to normal. Supportive treatment with pamidronate does not induce bone healing in MM. Therefore, the results observed with the addition of calcitriol suggest that this hormone may have contributed to the apparent arrest of the progression of MM and caused stimulation of bone healing.

Role of spiral computed tomography in the diagnosis of pulmonary embolism in the emergency department.

Recently a debate has developed in the medical community as radiologists in some centers suggest the selective substitution of spiral computed tomography (CT) for ventilation-perfusion (V/Q) nuclear medicine imaging as a screening test for the diagnosis of acute pulmonary embolism. Proponents of spiral CT argue that it is more accurate than the usual practice of combining the (V/Q) scan and the physician's best clinical judgment. V/Q scans classify patients into groups according to the probability of pulmonary emboli, whereas the thrombus is visible with spiral CT. Opponents point out that large-scale patient outcome studies using spiral CT have not been completed, but such information is available for (V/Q) scans. Most clinicians are familiar with the strengths and limitations of an assessment that relies primarily on the (V/Q) scan, because this examination has been available for many years. Although spiral CT does not perform as well as pulmonary arteriography in detecting subsegmental emboli, the importance of smaller peripheral emboli is controversial. This review explores the advantages and disadvantages of investigations currently available for the diagnosis of acute pulmonary embolism from the perspective of the emergency physician, presenting the view that spiral CT is likely to have an increasingly important place in patient evaluation.

Empiric assessment of parameters that affect the design of multireader receiver operating characteristic studies.

RATIONALE AND OBJECTIVES: The authors attempted to assess experimentally the magnitude of reader variability and the correlations and interactions among cases, readers, and modalities during observer performance studies and their possible effects on study design and sample size. MATERIALS AND METHODS: Published data from 32 selected receiver operating characteristic (ROC) studies were reviewed to compare the magnitude of the variance component from readers with the variance component from modality. Estimates of correlation and interactions among cases, readers, and modalities were also computed directly from ROC data ascertained during two large studies performed in our laboratory. Each of these two studies included 529 cases and six readers, but one study used eight modalities and the other nine. RESULTS: Published results indicate that reader variability is task dependent and larger (P < .05) than modality variability in detection of interstitial disease. Measured correlations between modalities for the same reader were task dependent and ranged from 0.35 to 0.59. Modality-by-reader and modality-by-case interactions often are not important factors. The random error term was greater than the modality-by-reader interaction in 11 of 20 comparisons and greater than the modality-by-case interaction in eight of 20 comparisons. CONCLUSION: Use of the same cases interpreted with different modes is justifiable in many situations because of the high variability from readers. This comprehensive review of existing ROC studies resulted in parameter assessments that can be used to better estimate sample-size requirements in multireader ROC studies.

Changes in lung volume and volume of emphysema after unilateral lung reduction surgery: analysis with CT lung densitometry.

PURPOSE: To evaluate changes in volume of the lungs and volume of emphysema after unilateral lung reduction surgery (ULRS) by using computed tomographic (CT) lung densitometry. MATERIALS AND METHODS: Twenty-eight patients underwent CT before and 3 months after ULRS. With use of a density mask software program and a three-dimensional graphics workstation, CT scans were analyzed to define the volume of the lungs and the volume of emphysema. Pre- and postoperative mean CT numbers were determined. RESULTS: After ULRS, the surgically reduced lung volume decreased 22%, and the intact opposite lung volume increased 4%. Emphysema in the surgically reduced lung decreased 14% and was unchanged in the intact opposite lung. Mean CT numbers in the surgically reduced lung increased 26 HU but were unchanged in the intact opposite lung. CONCLUSION: The effects of ULRS on each lung can be evaluated by using CT lung densitometry and a three-dimensional graphics workstation. ULRS reduces emphysema and lung volume in the surgically reduced lung without statistically significant worsening of contralateral emphysema at 3 months.

Pulmonary infiltrates following administration of paclitaxel.

The clinical spectrum of hypersensitivity reactions reported with paclitaxel has not included the occurrence of pulmonary infiltrates. This report describes three patients who developed transient pulmonary infiltrates after receiving paclitaxel. These infiltrates were noted 2 days to 2 weeks after administration of paclitaxel. The infiltrates resolved spontaneously in all the patients but one of them did receive steroid therapy. This syndrome of transient pulmonary infiltrates did not reoccur in the two patients who were rechallenged with paclitaxel. Physicians should be made aware of this unique occurrence during the course of treatment with paclitaxel.

Improvement in pulmonary function and elastic recoil after lung-reduction surgery for diffuse emphysema.

BACKGROUND: Pulmonary function may improve after surgical resection of the most severely affected lung tissue (lung-reduction surgery) in patients with diffuse emphysema. The basic mechanisms responsible for the improvement, however, are not known. METHODS: We studied 20 patients with diffuse emphysema before and at least three months after either a unilateral or a bilateral lung-reduction procedure. Clinical benefit was assessed by measurement of the six-minute walking distance and the transitional-dyspnea index, which is a subjective rating of the change from base line in functional impairment and the threshold for effort- and task- dependent dyspnea. Pressure-volume relations in the lungs were measured with static expiratory esophageal-balloon techniques, and right ventricular systolic function was assessed by echocardiography. RESULTS: The patients had significant improvement in the transitional-dyspnea index after surgery (P<0.001). The mean (+/-SD) coefficient of retraction, an indicator of elastic recoil of the lung, improved (from 1.3+/-0.6 cm of water per liter before surgery to 1.8+/-0.8 after, P<0.001). Sixteen patients with increased elastic recoil had a greater increase in the distance walked in six minutes than the other four patients, in whom recoil did not increase (P=0.02). The improved lung recoil led to disproportionate decreases in residual volume as compared with total lung capacity (16 percent vs. 6 percent), but the decreases in both values were significant (P<0.001). Forced expiratory volume in one second increased (from 0.87+/-0.36 to 1.11+/-0.45 liters, P<0.001). End-expiratory esophageal pressure also decreased (P=0.002). These improvements in lung mechanics led to a decrease in arterial partial pressure of carbon dioxide form 42+/-6 to 38+/-5 mm Hg (P=0.006). Furthermore, the fractional change in right ventricular area, an indicator of systolic function, increased from 0.33+/-0.11 to 0.38+/-0.010 (P=0.02). CONCLUSIONS: Lung-reduction surgery can produce increases in the elastic recoil of the lung in patients with diffuse emphysema, leading to short-term improvement in dyspnea and exercise tolerance.

Unilateral thoracoscopic surgical approach for diffuse emphysema.

We evaluated the use of a lateral thoracoscopic approach for lung reduction surgery in patients with diffuse emphysema. Sixty-seven patients with a mean age of 61.9 years underwent operation. Operative side was determined by preoperative imaging. The procedures were laser ablation in 10 patients and stapler resection in 57 patients. Ten patients, including six of the 10 patients in the laser-only group had poor outcome (death or hospitalization longer than 30 days), leading us to abandon the laser technique. Of the remaining 57 patients undergoing primary stapled resection, duration of chest tube placement averaged 13 days (range 3 to 53 days) with a mean hospital stay of 17 days (range 6 to 99 days). Seven patients required ventilation for longer than 72 hours, six patients underwent conversion of the procedure to open thoracotomy, four patients acquired arrhythmias, and three patients were treated for empyema. There was one early death (1.7%), from cardiopulmonary failure. Forty patients returned for 3-month evaluation. Significant (p < 0.0001) improvements were seen in forced vital capacity (2.69 L after vs 2.26 L before) and forced expiration volume in 1 second (1.04 L after vs 0.82 L before), with 25 of 40 patients (63%) showing an improvement of more than 20%. Lung volume measures, in particular residual volume, fell significantly. Arterial blood gas analysis revealed that carbon dioxide tension fell significantly in patients with preoperative hypercapnia (carbon dioxide tension > 45 mm Hg, p = 0.018). Six-minute walk test results improved (894 feet after vs 784 feet before, p = 0.002), and symptomatic benefit was confirmed by significant improvement in the dyspnea index. The combination of both hypercapnia and reduced single-breath diffusing capacity for carbon monoxide was significantly more frequent (p = 0.0026) and was 86% specific (5 of 6 patients) in predicting serious postoperative risk. We conclude that the lateral thoracoscopic surgical approach to diffuse emphysema offers significant improvement in pulmonary mechanics and functional impairment. Patients with a combination of hypercapnia and reduced single-breath diffusing capacity for carbon monoxide should not be considered for this procedure because of significant perioperative risk.

Selection of processing algorithms for digital image compression: a rank-order study.

RATIONALE AND OBJECTIVES: We investigated non-receiver operating characteristic (non-ROC) methods for the selection of processing algorithms for digital image compression. METHODS: We performed a multipoint, rank-order study with 20 posteroanterior chest images, each processed using four different algorithms. Seven radiologists reviewed these alongside the digitized noncompressed image. Observers were forced to rank order the similarity and/or difference of the processed images to the nonprocessed image in each case. RESULTS: A two-way analysis of variance of the rankings was statistically significant (p = .025), indicating that one processing scheme yielded images that were clearly perceived as the most similar to the nonprocessed images. The selected processing scheme was not the one that yielded the lowest quantitative difference from the nonprocessed images as measured by root mean square error. CONCLUSION: Non-ROC study designs that are highly sensitive to small differences among similar images can be used to select processing algorithms.

Imaging of the normal trachea.

Tracheal evaluation is a fundamental part of chest imaging. Adult tracheal anatomy is well understood, but tracheal embryology is not. There have been major advances in imaging, but radiography remains the initial imaging study for most tracheal pathology. Careful radiographic analysis can yield considerable information.

Cutaneous exposure to warfarin-like anticoagulant causing an intracerebral hemorrhage: a case report.

A case of intercerebral hematoma due to warfarin-induced coagulopathy is presented. The 39-year-old woman had spread a warfarin-type rat poison around her house weekly using her bare hands, with no washing post application. Percutaneous absorption of warfarin causing coagulopathy, reported three times in the past, is a significant risk if protective measures, such as gloves, are not used. An adverse drug interaction with piroxicam, which she took occasionally, may have exacerbated the coagulopathy.

Superior sulcus tumors: treatment selection and results for 85 patients without metastasis (Mo) at presentation.

Superior sulcus (Pancoast) tumors (SST) are uncommon carcinomas of the lung with distinctive failure patterns and a somewhat more favorable prognosis than other sites of lung cancer. The most effective use of surgery (S), radiation (R), and chemotherapy (C) is not resolved. Most reported series include patients treated before the era of computed tomography (CT). A retrospective study was undertaken of all previously untreated patients with SST who received definitive management at the University of Texas M.D. Anderson Cancer Center between January 1977 and December 1987. Eighty-five patients were treated: the male:female ratio was 2.7:1, and the ages ranged from 35 to 80 (median 59) years. Karnofsky performance status (KPS) was 80 or more in 70 patients (82%). Thirty patients (35%) had lost 5% or more body weight. All had histologic or cytologic confirmation of carcinoma: 25% were squamous cell, 2% small cell, 54% adenocarcinoma, and 6% were large cell carcinoma (12% were not classified). After complete evaluation, 43 were classified as clinical Stage IIIA and 42 were Stage IIIB. One Stage IIIA patient received surgery, 13 surgery + radiation therapy, 2 surgery + radiation therapy and chemotherapy, 19 radiation therapy and 8 radiation therapy + chemotherapy. Seven Stage IIIB patients received surgery + radiation therapy, 12 radiation therapy, 2 surgery + radiation therapy + chemotherapy, 17 radiation therapy + chemotherapy and 4 chemotherapy. Surgery was a component of therapy more frequently in Stage IIIA than IIIB (p less than .05) and systemic treatment chemotherapy was used significantly more often (p less than .01) in Stage IIIB. Twenty-six patients (31%) lived 2 years or more (25+ to 131+ months) after treatment. Stage IIIA patients had a 46.5% 2-year survival rate compared to 20.6% for Stage IIIB (p = .0042). The one patient treated with surgery alone lived 2 years; 23% (7/31) of patients who had radiation therapy alone and none of the 4 who had chemotherapy lived 2 years. When surgery was a component of treatment, 52% (13/25) lived 2+ years, compared with 22% (13/60) when surgery was not part of treatment. When radiation therapy was part of treatment 31% lived 2 years and when chemotherapy was used, 18% lived 2 years. Fifty-two patients (61%) had control of the local tumor: their survival was significantly greater (p less than .01) than those who had local failure.(ABSTRACT TRUNCATED AT 400 WORDS)

Diffuse large-cell lymphoma of B-cell origin and deficient T-cell function in a patient with rheumatoid arthritis.

An increased incidence of non-Hodgkin's lymphoma has been described in patients with rheumatoid arthritis. Mechanisms related to abnormal immune regulation have been postulated, but no patients with rheumatoid arthritis and lymphoma have been previously well characterized immunologically. We describe here a patient with long-standing rheumatoid arthritis in whom a B-cell diffuse large-cell lymphoma developed. He was found to have a severe T-cell immunodeficiency and evidence of persistent Epstein-Barr virus infection. Epstein-Barr nuclear antigen was not found to be present within lymphoma cells. The combination of defective T-cell function and persistent Epstein-Barr virus infection may have predisposed this patient with rheumatoid arthritis to the development of a malignant clone of B lymphocytes.

The chest radiograph after resection of pulmonary nodules with a neodymium-YAG laser.

We studied the chest radiographs of 30 patients (39 thoracotomies) after resection of pulmonary nodules with a neodymium-YAG laser. New "nodules" were often visible in the resected areas. These gradually evolved into linear scars with or without a small, nodular component or disappeared. In 11 of 39 thoracotomies, postresection cavities developed at the site of the lesion. Familiarity with the typical radiographic findings after laser resection and their normal evolution is necessary to avoid confusing these expected findings with residual or recurrent disease or with infection following surgery.