HOLTER心电图临床操作及相关故障分析处理

本文较全面的介绍了动态心电图系统的功能特性 ,临床应用价值 ,临床操作及病人生活日志记录指导 ,工作报告编辑注意事项 ,相关故障现象、原因及处理。     

Bronchial symptoms and respiratory function in workers exposed to methylmethacrylate.

This study aimed to investigate the pulmonary effects of methylmethacrylate (MMA) in a group of occupationally exposed workers. In the exposed group 20% had chronic cough compared with 1% in controls. Spirometric values at the beginning of the workshift were similar in both groups, but a mild airways obstruction appeared during the workshift. The maximum expiratory flow when 50% of the forced vital capacity remained to be exhaled (MEF50) and the ratio of MEF50 to maximal expiratory flow (MEF50/MEF) decreased significantly during the workshift among exposed workers v controls (p = 0.04 and 0.01 respectively). Results remained unaffected after adjustment for smoking. Exposure to MMA seems to be responsible for a mild airways obstruction but further study on a larger population would be useful.     

48-hour ambulatory electrocardiography in dynamite workers and controls

ABSTRACT Sudden deaths and chronic cardiovascular diseases have been reported in excess frequency from the explosives industry. Forty-two active dynamite workers and 43 healthy, unexposed workers have been studied by ambulatory electrocardiographic monitoring during two 24-hour periods covering an exposed shift and the “abstinence phase,” 40-64 hours after the last exposure to dynamite. To achieve comparability the non-exposed individuals were screened for risk factors of heart disease in the same way as those employed in exposed work. No statistically significant differences were found between the groups concerning the mean individual number of ventricular or supraventicular ectopic beats per hour or per 10 000 heart beats during the whole recorded time. Among those who showed only ectopic beats in one of the two periods dynamite workers tended to have more ectopic beats in the second period. “Complicated” ventricular ectopic beats (multifocal, bigemeny, or coupled) were seen in six dynamite workers and four controls. The only observed period of ventricular tachycardia was seen in a dynamite worker on Monday morning. The mean individual corrected QT-time was similar between the two groups, and there was no tendency towards longer QT-times among the dynamite workers during the abstinence period. Continuous monitoring detected several cases with pronounced ventricular arrhythmias despite normal short-time ECG and may be used to investigate the heart rhythm in active workers.     

Specific features of adverse effects in workers exposed to different levels of methylmethacrylate

The relation of the incidence of malignant neoplasms to the dose of methyl methacrylate (MMA) was studied in 3588 workers. There was a clear correlation between the dose of MMA and the risk for cancer of the genital system in females and of the lung in males. Examining the immunity in groups receiving different doses of MMA revealed significant immunological disorders when exposed to its high concentrations.     

Cancer mortality among workers exposed to formaldehyde

Proportionate mortality among workers exposed to formaldehyde was analyzed among employees of a large chemical plant in Western Massachusetts. Twenty-four such decedents, all males, were identified through union records, reports of former coworkers, and a systematic review of obituaries in local newspapers. Work histories were obtained from seniority lists. Race-age-sex-adjusted proportionate mortality ratios (PMRs) were significantly elevated for cancer of the colon based on United States. county, and county cancer mortality proportions (PMR = 702, 424, 333, p ≤ 0.05). as were PMRs for the category buccal and pharyngeal cancer (PMR = 870, 952, 833. p < 0.05). This study provides evidence of formaldehyde's carcinogenicity. These findings are at variance with a previous report of the mortality experience of workers at the same plant from an earlier period.     

Ocular disorders among workers exposed to mercury

Mercury vapor exposed workers may show ocular changes, as well as other systems affection. A sample of 84 workers in preparing mercury fulminate were examined for conjunctival corneal and lenticular manifestation of long duration exposure, together with mercury urinary output. Lens changes were found in 50% of the involved workers while keratopathy as recorded in 34.5% of them. No statistically significant association was found between the occurrence of eye lesions and levels of urinary elimination of mercury. These results suggest local absorption of this element is most probably the underlying cause of ocular affection.     

Mortality among industrial workers exposed to phenol

We conducted a follow-up study to evaluate mortality among 14,861 workers employed in five facilities producing or using phenol and formaldehyde. More than 360,000 person-years of follow-up accrued. Mortality rates from all causes of death combined were similar to those in the general U.S. population. We observed excesses of cancer of the esophagus, cancer of the kidney, and Hodgkin's disease among workers exposed to phenol, but none of these excesses showed a dose-response relation with exposure to phenol. Excess lung cancer mortality (SMR = 1.2) showed no consistent pattern by any exposure index. Workers exposed to phenol had lower mortality ratios for cancer of the buccal cavity and pharynx, cancer of the stomach, cancer of the brain, arteriosclerotic heart disease, emphysema, disease of the digestive system, and cirrhosis of the liver. Of these, arteriosclerotic heart disease, emphysema, and cirrhosis of the liver were inversely related to duration of phenol exposure and to cumulative phenol exposure levels. Although these inverse associations may be due to chance or uncontrolled confounders, the ability of phenol to interfere with the generation of oxidants in experimental systems suggests that the pattern may have biologic plausibility.     

三硝基甲苯作业工人白内障患病调查

目的了解三硝基甲苯(TNT)作业人员眼部的损害情况。方法对某炸药厂作业人员542人进行体检,重点检查眼部白内障患病情况,对结果进行统计学分析。结果检出TNT白内障患者90例,其中Ⅲ期患者1例,Ⅱ期17例,I期72例,总患病率为16.6%,其中男性23.46%,女性3.26%;检出观察对象343人,总检出率63.28%,其中男性75.70%,女性39.13%,患病率及检出率男性均高于女性(P<0.05);患病率随年龄、TNT暴露程度以及工龄增加而上升(P<0.05)。结论所调查炸药厂三硝基甲苯作业人员白内障患病率较高,性别、工种、年龄、工龄与TNT白内障发生密切相关。     

Hematotoxocity among Chinese workers heavily exposed to benzene

Benzene is a well-established hematotoxin. However, reports of its effects on specific blood cells have been somewhat inconsistent and the relative toxicity of benzene metabolites on peripheral blood cells in humans has not been evaluated. We compared hematologic outcomes in a cross-sectional study of 44 workers heavily exposed to benzene (median: 31 parts permillion [ppm] as an 8-hr time-weighted average [TWA] and 44 age and gender-matched unexposed controls from Shanghai, China. All hematologic parameters (total white blood cells [WBC], absolute lymphocyte count, platelets, red blood cells, and hematocrit) were decreased among exposed workers compared to controls, with the exception of the red blood cell mean corpuscular volume (MCV), which has higher among exposed subjects. In a subgroup of workers who were not exposed to more than 31 ppm benzene on any of 5 sampling days (n = 11, median 8 hr TWA = 7.6 ppm, range = 1–20 ppm), only the absolute lymphocyte count was significantly different between exposed workers (mean [sd] 1.6 [0.4] x 10³ μL) and controls (1.9 [0.4] x 10³ μL, p = 0.03). Among exposed subjects, a dose-response relationship with various measures of current benzene exposure (i.e., personal air monitoring, benzene metabolites in urine) was present only for the total WBC count, the absolute lymphocyte count, and the MCV. Correlations between benzene metabolites and hematologic parameters were generally similar, although hydroquinone was somewhat more strongly associated with a decrease in the absolute lymphocyte count, and catechol was more strongly associated with an increase in MCV. Morphologic review of peripheral blood slides demonstrated an excess of red blood cell abnormalities (i.e., stomatocytes and target cells) only in the most heavily exposed workers, with no differences in granulocyte, lymphocyte, or platelet morphology noted. Although benzene can affect all the major peripheral blood elements, our results support the use of the absolute lymphocyte count as the most sensitive indicator of benzene-induced hematotoxicity. © 1995 Wiley-Liss, Inc.     

Immunological changes among workers occupationally exposed to styrene

The functional status of the immune system was investigated in a group of 71 workers exposed to styrene and in 65 control subjects, recruited according to the same selection criteria and comparable as to sex, age, and confounding variables. Air and biological monitoring were used to characterize styrene exposure (median of the main urinary metabolites in the next-morning spot samples: 106 mg/g creatinine). Phenotypic analysis of peripheral blood lymphocytes (PBL) by automated flow cytometry revealed a reduced proportion of T lymphocyte subsets (CD3⁺, CD4⁺ and CD4⁺45⁺), with no changes in CD8⁺, and a higher proportion of B lymphocytes (CD19⁺) among styrene-exposed workers. The exposed workers showed a higher proportion of activation markers, namely DR and interleukin-2 receptors (CD25). Immunoglobulin subclasses were comparable in the two groups. An increased prevalence of abnormally low values was apparent for CD2⁺, CD3⁺, CD4⁺, CD4⁺45⁺ and CD11b subsets among workers exposed to styrene, whereas CD19⁺, DR⁺ and CD25⁺ showed an increased prevalence of abnormally high values. Natural killer-related phenotypes (CD56⁺, CD56+16⁺, and CD56⁺16^–) were more expressed among styrene workers, with average increase of 30%. However, the frequency distribution of the lytic activity of natural killer cells against K-562 target cells was shifted towards lower values in the exposed workers as compared to control subjects. Dose-response relationships between indices of internal dose and prevalence of abnormal values were detectable for T lymphocyte subsets, NK phenotypes, and activation markers. These findings suggest that moderate exposure to styrene is associated with an altered distribution of lymphocyte subsets. The decreased proportion of T lymphocytes, mainly of T helper-inducer cells, could hamper regulatory functions, thus suggesting a negative modulation by styrene exposure. Since a proper balance between immunocycte subsets is important for immunological responses, such changes should be regarded as adverse effects.     

Mortality among workers exposed to polychlorinated biphenyls.

On the basis of evidence from animal studies, polychlorinated biphenyls (PCBs) are considered potentially carcinogenic to humans. However, the results of studies in human populations exposed to PCBs have been inconsistent. The authors conducted a retrospective cohort analysis (1957-1986) comparing the mortality of 3,588 electrical capacitor manufacturing workers with known exposure to PCBs with age-, sex-, and calendar time-specific mortality rates for all whites in the United States. Proportional hazards modeling was also performed to examine the association between cumulative PCB exposure and site-specific cancer mortality. All-cause mortality (192 deaths observed, 283.3 expected) and total cancer mortality (54 deaths observed, 63.7 expected) were lower than expected. More deaths were observed than expected for malignant melanoma (8 observed, less than 2.0 expected) and cancer of the brain and nervous system (5 observed, 2.8 expected). The average estimated cumulative dose for the cases of brain cancer (22.9 units) was greater than for other workers (12.9 units), but the 95% confidence intervals around this difference were broad. The risk of malignant melanoma was not related to cumulative PCB exposure. These results provide some evidence of an association between employment at this plant and malignant melanoma and cancer of the brain. The possibility that the results are due to chance, bias, or confounding cannot be excluded.     

Cancer incidence among Danish workers exposed to trichloroethylene

Human evidence regarding the carcinogenicity of the animal carcinogen trichloroethylene (TCE) is limited. We evaluated cancer occurrence among 803 Danish workers exposed to TCE, using historical files of individual air and urinary measurements of TCE-exposure. The standardized incidence ratio (SIR) for cancer overall was close to unity for both men and women who were exposed to TCE. Men had significantly elevated SIRs for non-Hodgkin's lymphoma (SIR = 3.5; n = 8) and cancer of the esophagus (SIR = 4.2; n = 6). Among women, the SIR for cervical cancer was significantly increased (SIR = 3.8; n = 4). No clear dose-response relationship appeared for any of these cancers. We found no increased risk for kidney cancer. In summary, we found no overall increase in cancer risk among TCE-exposed workers in Denmark. For those cancer sites where excesses were noted, the small numbers of observed cases and the lack of dose-related effects hinder etiological conclusions.     

Effects of occupational noise exposure on 24-hour ambulatory vascular properties in male workers

BACKGROUND: Epidemiologic studies have demonstrated that occupational noise exposure is associated with hypertension, but the related mechanism in vascular structural changes is unclear. OBJECTIVE: This panel study aimed to investigate effects of occupational noise exposure on ambulatory vascular structural properties in male workers. METHODS: We recruited 20 volunteers and divided them into a high-noise-exposure group of 15 and a low-noise-exposure group of 5 based on environmental noise measurement in an automobile manufacturing company. We determined individual noise exposure and measured personal ambulatory vascular property parameters simultaneously during 24 hr. Linear mixed-effects regression models were used to estimate transient and sustained effects of noise exposure on vascular parameters by adjusting some confounders collected from self-administrated questionnaires and health checkups. RESULTS: The high-noise-exposed (85 +/- 8 dBA) workers had significantly higher systemic vascular resistance (SVR) than the low-noise-exposed workers (59 +/- 4 dBA) during work and sleep periods. Contrarily, low-noise-exposed workers had significantly higher brachial artery compliance (BAC), brachial artery distensibility (BAD), and systemic vascular compliance (SVC; marginal, p = 0.07) than high-noise-exposed workers during off-duty periods. We also found that high-noise-exposed workers had significantly lower BAC (1.38 +/- 0.55 %mL/mmHg) and BAD (1.29 +/- 0.51 %/mmHg), as well as lower SVC (0.24 +/- 0.10 mL/L/mmHg), but higher SVR (1.93 +/- 0.67 mL/L/min) compared with low-noise-exposed workers over a 24-hr period. CONCLUSIONS: Our findings suggest that in automobile workers, occupational noise exposure may have sustained, not transient, effects on vascular properties and also enhances the development of hypertension.     

Cancer incidence and mortality among workers exposed to acrylonitrile

A cohort of 1,083 male employees who had potential for exposure to acrylonitrile between 1944 and 1970 at a Du Pont textile fibers plant were followed through 1981 for mortality and through 1983 for cancer incidence. In total, the 21 cancer deaths were fewer than expected based on either Du Pont or U.S. rates. No significant excesses were seen by primary site. In all, 37 cancer cases occurred as compared with 36.5 expected based on company rates. Five lung cancer cases were observed and 6.9 expected. There were 5 prostate cancer cases as compared with 1.9 expected. Of these, 4 occurred among wage employees during the 1975-1983 period, compared to 0.9 expected. This excess was statistically significant.