Is coronary angiography necessary for vascular surgery patients who have positive results of dipyridamole thallium scans?

PURPOSE: Because dipyridamole thallium (DT) scanning is a useful predictor of perioperative cardiac events, a positive results of a DT scan is frequently the basis for performing more invasive cardiac evaluation and for consideration for performing coronary revascularization procedures before performing peripheral vascular surgery. The rationale for this approach has been that the treatment of anatomically significant coronary artery disease would lower the risk of performing a subsequent vascular operation. However, the benefit of performing aggressive diagnostic and therapeutic cardiac procedures in such patients remains unproved. To examine this issue, data from patients who underwent coronary angiography because of thallium redistribution were compared with data from matched control subjects who underwent peripheral vascular operations without further cardiac evaluation. METHODS: The medical records of 70 consecutive patients who underwent coronary angiography because of the presence of two or more segments of redistribution on DT scan were reviewed and compared with 70 other patients matched with respect to age, gender, peripheral vascular operation, and number of segments of redistribution on DT scan who did not undergo additional cardiac evaluation. RESULTS: DT scans were performed on 934 preoperative peripheral vascular surgery patients to help in the assessment of operative risk. Ischemic responses, defined as two or more segments of redistribution, were observed in 297. Of these, 70 underwent cardiac catheterization and 25 underwent coronary revascularization procedures. Adverse outcomes affected 46% of the coronary angiography group and 44% of the control group (p = NS). Patients who underwent coronary angiography and were considered for myocardial revascularization had fewer cardiac events with a subsequent vascular operation than did the control subjects. However, any possible benefit from invasive cardiac evaluation was offset by the three deaths and two myocardial infarctions (MIs) that complicated the cardiac evaluation. There was no significant difference between the angiography group and the matched control subjects with respect to perioperative nonfatal MI (13% vs 9%), fatal MI (4% vs 3%), late nonfatal MI (16% vs 19%), or late cardiac death (10% vs 13%). In long-term follow-up, MIs occurred later in patients who underwent coronary angiography than the control subjects (p = 0.049), but this difference was not associated with an improvement in the overall survival rate. CONCLUSIONS: The risks of extended cardiac evaluation and treatment did not produce any improvement in either the perioperative or the long-term survival rate. For most vascular surgery patients who have a positive result of a DT scan, coronary angiography does not provide any additional useful information.     

Evaluation and risk stratification of patients with chest pain in the emergency department. Predictors of life-threatening events

While assessing chest pain in the emergency department, physicians must first estimate the probability of acute ischemic states in the patient. This first estimate is based on the patient's history, physical examination, and electrocardiogram. Patients who meet the threshold for acute cardiac ischemia are further evaluated to confirm or exclude this diagnosis, while other life-threatening factors are excluded.     

Cavitary necrosis complicating pneumonia in children: sequential findings on chest radiography

We tested the hypothesis that the obese (fa/fa) Zucker rat has a sleep organization that differs from that of lean Zucker rats. We used the polygraphic technique to identify and to quantify the distribution of the three main states of the rat: wakefulness (W), non-rapid-eye-movement (NREM), and rapid-eye movement (REM) sleep states. Assessment of states was made with light present (1000-1600), at the rats thermoneutral temperature of 29 degrees C. Obese rats, compared with lean ones, did not show significant differences in the total time spent in the three main states. Whereas the mean durations of W and REM states did not differ statistically, that of NREM did (P = 0.046). However, in the obese rats, the frequencies of switching from NREM sleep to W, which increased, and from NREM to REM sleep, which decreased, were statistically significantly different (P = 0.019). Frequency of switching from either REM or W state was not significantly different. We conclude that sleep organization differs between lean and obese Zucker rats and that it is due to a disparity in switching from NREM sleep to either W or REM sleep and the mean duration of NREM sleep.     

Evaluation of pulmonary arterial trunk on frontal chest radiograph in patients with atrial septal defects

Atrial septal defect (ASD) is one of the most common congenital cardiac anomalies encountered in adulthood. The evaluation of the pulmonary hypertension in ASD is clinically important for operative indication and prognosis. The pulmonary vasculature in chest radiographs in patients with ASD is characterized as dilatation of the central pulmonary arteries and increase of the peripheral pulmonary vessels in patients without pulmonary arterial hypertension (PH) and constriction of the peripheral pulmonary arteries in those with pulmonary hypertension. While the dilatation of the main pulmonary artery occurs in the patients both with and without pulmonary hypertension, its precise radiographic evaluation with regard to the morphological and hemodynamic change of the right ventricle and pulmonary arteries has not been reported. This study was to determine if the contour of the main pulmonary artery segment of the cardiac silhouette in the conventional frontal chest radiograph could be used 1) as indicators of PH or raised right ventricular pressure and 2) as a reliable base for evaluation of the size of the right ventricule (RV) in ASD. The intersection of the line (line A) drawn tangentially to the lateral lower margin of the main pulmonary artery segment to the horizontal line at the left hemidiaphragm is closely related to the apex of RV as measured by right ventricular angiography in supine position. The ratios of the distance of the intersection from the midline of the frontal chest radiograph to the internal diameter of the left hemithorax in normal subjects were 0.50 +/- 0.08 (mean +/- standard deviation) for male and 0.54 +/- 0.09 for female. The ratio increased with increasing left-to-right shunt [0.59(Qp/QS < 2), and 0.71 (Qp/QS > 2)] and shows a tendency of decrease with raised right ventricular systolic pressure (0.52-0.64 in normal subjects and patients with mild raised right ventricular systolic pressure and 0.43 in patients with severe raised right ventricular systolic pressure). The measurement of the angle of the line A from the vertical line tends to show increasing decrease with raised pulmonary arterial and right ventricular systolic pressure (20.1 degrees +/- 4.9 in mild PH and 10.3 degrees +/- 4.1 in moderate to severe PH). The decrease of the angle of the line A to the vertical line was well correlated with conventional radiographic criteria of the right and left central pulmonary arteries of PH.(ABSTRACT TRUNCATED AT 400 WORDS)     

Comparison of persistent thallium perfusion defects by quantitative washout analysis with thallium reinjection in patients with coronary artery disease

Thallium reinjection can improve the detection of severely ischemic viable myocardium in patients with coronary artery disease. However, a disadvantage of this method is that it requires the acquisition of 3 separate sets of images and the administration of an additional dose of the radiotracer. Alternatively, quantitative analysis of the regional myocardial washout of thallium-201 can be easily obtained from the conventional postexercise and redistribution images without additional imaging time or radiation exposure to the patient. To determine whether this method can predict the results of thallium reinjection, this study analyzed thallium-201 images of 31 patients who had persistent perfusion defects in qualitative exercise/delayed redistribution single-photon emission computed tomographic thallium studies and who underwent thallium reinjection. The quantitative mean radioactive counts of each myocardial segment that had a persistent perfusion defect in the initial and delayed redistribution on 4-hour short-axis tomographic slices were measured to derive a delayed/initial ratio, and these values were compared with the results of thallium reinjection. The delayed/initial ratio was 1.06 +/- 0.22 in 39 segments that improved, versus 0.58 +/- 0.18 in 43 segments without improvement after reinjection (p < 0.001). Thirty-eight of the 39 segments that improved had a ratio of > or = 0.75, versus only 3 of the 43 segments that showed no improvement (sensitivity, 98%; specificity, 91%). The correlation between the delayed/initial ratio and reinjection results was equally high at any segment location or severity. It is concluded that quantitative regional thallium washout analysis predicts the results of thallium reinjection in segments with persistent thallium defects.(ABSTRACT TRUNCATED AT 250 WORDS)     

Do nurses avoid AIDS patients? Avoidance behaviours and the quality of care of hospitalized AIDS patients

This article explores the potential impact upon people with disability of some of the technological information being uncovered by the Human Genome Project. While the project has been promoted as promising positive benefits to society, its effect, in our present values climate, is potentially damaging. While we can map impairment, we cannot, as yet, cure it. And, in a society which embraces values such as utilitarianism and economic rationalism, we are choosing more and more to eliminate rather than care. We are seeing a conceptual transformation--the geneticization of self--which has enormous implications for the lives of people with disability. The author argues that scientific endeavor, which has been constructed as occurring within a culture of impartiality and empiricism, actually operates within an uncontested value base which devalues disability. She concludes that the Human Genome Project needs to be reframed within a broadened ethical framework of inclusion.     

密闭消解-电感耦合等离子体质谱法测定铅矿石中痕量镓铟铊镉锗

铅矿床具有较高品位的各种稀散元素,因此准确测定铅矿石中Ga、In、Tl、Cd、Ge,对于矿产资源的节约、开发利用等具有重要意义。采用密闭消解方式处理样品,同时在消解过程中加入H₂SO₄(1+4)并水浴加热以沉淀分离Pb基体,分别选择⁶⁹Ga、¹¹⁵In、²⁰⁵Tl、¹¹⁴Cd、⁷²Ge作为分析同位素,¹⁰³Rh为内标校正Ga、In、Cd、Ge,¹⁸⁷Re为内标校正Tl,实现了电感耦合等离子体质谱法对铅矿石中痕量稀散元素Ga、In、Tl、Cd、Ge的测定。实验表明,采用标准(STD)模式测定,Ga、Tl、Cd的背景等效浓度比动能歧视(KED)模式高出一个数量级,而In、Ge的背景等效浓度和KED接近,因此确定采用KED模式测定Ga、Tl、Cd,采用STD模式测定In、Ge;对KED模式下He气流速进行了优化,确定He气流速为5.8mL/min。方法线性方程的相关系数均不小于0.9992,Ga、In、Tl、Cd、Ge的方法检出限分别为0.0520、0.0392、0.0196、0.0212、0.0437μg/g。采用实验方法测定铅矿石实际样品中Ga、In、Tl、Cd、Ge,测得结果的相对标准偏差(RSD,n=6)为1.3%~5.0%,加标回收率为86%~112%。将实验方法应用于铅矿石标准物质中这5个元素的测定,所得结果与认定值吻合。     

Mottle on computed radiographs of the chest in pediatric patients

PURPOSE: To investigate the relationship between radiation exposure and perceived mottle at bedside pediatric chest examinations performed with screen-film and computed radiographic techniques. MATERIALS AND METHODS: In a pediatric intensive care unit, chest radiographs were obtained with both computed radiography (60 radiographs) and a 600-speed screen-film system (14 radiographs). The relative radiation exposure was estimated by using the sensitivity value obtained in the processing of each computed radiograph. Five radiologists assessed the mottle present in the computed radiographs and screen-film images. RESULTS: For computed radiographs, the perceived level of mottle was inversely related to radiation exposure. For the same radiation exposure, the perceived mottle on computed radiographs was significantly higher than that on screen-film images (P < .001 for small cassettes; P < .01 for large cassettes). CONCLUSION: Pediatric computed radiography of the chest requires approximately twice the exposure of a 600-speed screen-film system to attain the same level of mottle.     

Evaluation of the efficacy of sequential intravenous-oral administration of pefloxacin in community-acquired lower respiratory tract infections in patients with underlying conditions

We studied the efficacy of sequential intravenous-oral pefloxacin therapy in community-acquired lower respiratory tract infection in 24 patients with one or more underlying conditions. Twenty-eight patients were enrolled into the study but only 24 patients were evaluated. There were 16 males and 8 females with a mean age of 66.9 +/- 11.2 years (mean +/- SD, range 46 to 87 years). The underlying conditions present were bronchiectasis, chronic obstructive lung disease and diabetes mellitus. Patients who were older than 70 years but without any underlying condition were also enrolled. All received 4 days of intravenous pefloxacin 400 mg twice a day followed by oral pefloxacin 400 mg twice a day for another 10 days. Assessment of success was based on clinical, microbiological and radiological improvement. Pefloxacin produced 79.2% clinical cure rate. Another 8.3% showed improvement. Pefloxacin was well tolerated. There were few adverse effects and none of the patients required a change of antibiotic. Pefloxacin was an effective and well tolerated treatment for respiratory tract infection and had the advantage of broad in-vitro antibacterial activity, twice daily dosing and sequential availability in an intravenous and oral formulation.     

Comparison of reticuloendothelial scans with bone scans in malignant disease

Thirty patients with histologically proven malignant disease were selected for reticuloendothelial scans and bone scans because of suspected bone or bone marrow involvement. Reticuloendothelial scans were abnormal in 83% of the patients and bone scans were abnormal in 47%. Focal defects on the reticuloendothelial marrow scan correlated better with tumor infiltration of the marrow than did diffusely abnormal scans. Focal defects were found in nine patients (30% of total), four of whom had negative or equivocal bone scans. In multiple myeloma, reticuloendothelial marrow scans were more sensitive than bone scans, but were not clearly better than bone scans in patients with solid tumors. In the interpretation of reticuloendothelial scans, consideration must be given to the effects of radiation, chemotherapy, and uremia, all of which may cause decreased reticuloendothelial uptake and falsely positive reticuloendothelial scans. Reticuloendothelial scans seem most useful for hematologic malignancies that have not been previously treated. The advantages and disadvantages of reticuloendothelial scans are discussed.     

Evaluation of routine postoperative chest X-rays in the management of the cardiac surgical patient

OBJECTIVES: To evaluate the role of routine chest X-rays in the management of patients post cardiac surgery. METHODS: 340 adult patients undergoing cardiac surgery were studied in three consecutive groups (A, B, C) of 100 patients each. Forty patients were excluded due to the intensive care stay greater than 36 h (n = 35), or early mortality within 36 h (n = 5). Routine chest X-rays were performed according to different protocols in Groups A and B. In group C there were no routine chest X-rays during the entire postoperative period [corrected]. In all three groups chest X-rays were performed where clinically indicated. Group A had three routine chest X-rays post-operation. Group B had one routine chest X-ray on day 4 post-operation. Group C had chest X-rays only when indicated. The X-rays were evaluated in terms of their assistance value and the resultant number of interventions. RESULTS: The three groups were similar preoperatively for age, sex, preoperative left ventricular function, presence of chronic obstructive airway disease and type of operation performed. The total number of chest X-rays in groups A, B and C were 304, 133 and 36, respectively. The number of chest X-rays leading to interventions were five, four and four in groups A, B and C, respectively. Chest X-rays that helped in management were 36, 28, and 28, respectively, in the same groups. There was no mortality or morbidity attributable to non-performance of routine chest X-ray. CONCLUSIONS: Routine chest X-rays post-cardiac surgery are of very little value and patients are adequately managed by performing chest X-rays only when clinically indicated. There was no increased mortality or morbidity attributed to lack of routine chest X-rays in any of these groups. We recommend performing chest X-rays only when clinically indicated in satisfactorily recovering adult cardiac surgical patients.     

Pneumonia in AIDS patients in the critical care unit

Despite advances in prophylaxis and the reduction of mortality and morbidity resulting from highly active antiretroviral therapy, neumocystis pneumonia remains a common problem in HIV-infected patients. There are many possible causes for the continued prevalence of this condition. This article examines the characteristics, and some of the complex causes of P. carinii pneumonia in AIDS patients.     

萃取反萃取原子吸收光谱法测定地质物料中的金、银、镓、铟、铊和碲

本文研究在盐酸(40％)、氢溴酸(8％)和碘化钾(0.15％)介质中,在抗坏血酸存在下(抑制铁干扰),用甲基异丁基酮(MIBK)萃取样液中的金、银、镓、铟、铊和碲,然后加入环己烷,将上述六种元素反萃取到硫脲液(4.5％)中,用火焰原子吸收光谱法在水相中测定。各元素测定精密度为4.1～6.7％,回收率为92～111％,适用于岩石、土壤等地质样品中六个元素的同时测定。