A result-oriented medical information system. An alternative to the conventional approach

A result-oriented medical information system at the Gulf Oil Corporation is described. Mortality data acquired mostly from routine company operations have been used to calculate standardized mortality ratios (SMRs) and life expectancy. Results show that male employees at the age of 20 have a life expectancy of 74.8 years. Compared with the U.S. general population at age 20 with a life expectancy of 71.8 years, Gulf employees have an advantage of exactly three years. Such an advantage may seem small, but it is equivalent to the gain that could be achieved if all deaths from cancer were eliminated in the United States, a hypothetical and impossible situation. These life expectancy data have the potential for use by the company to influence insurance premiums traditionally set by life insurance companies as well as to aid in the management of the company's pension fund. The SMR for all causes for the male employees is 0.82, significantly decreased in comparison with that of the U.S. general population. This favorable experience has been referred to as "the healthy worker effect." Cause-specific SMRs show a generalized pattern of deficits, some of which are statistically significant. None showed a significant increase. Seventy-six percent of the male deaths occurred among employees aged 65 years or older. If these annuitants (those alive at the beginning of the study) were not included and only the active workers were studied, an SMR of only 0.54 would be obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Long-term mortality of oil refinery workers. II. Comparison of the experience of active, terminated and retired workers

In occupational epidemiology a retrospective cohort study normally includes active, terminated, and retired employees and the mortality results may vary considerably if any of the three groups is excluded from the study. From a large refinery cohort of 12,526 white male workers followed between January, 1937 and January, 1978, the mortality experience of three groups (the active, terminated and retired) has been examined; detailed results, along with the merits and problems of studying these groups separately, are presented. The standardized mortality ratios (SMRs) for all causes are 0.68, 1.04 and 0.89 for the active, the terminated and the retired, respectively, and for all cancer, 0.85, 0.98 and 1.05. Significantly decreased SMRs are seen for most of the causes among the active and may be attributed to the "healthy worker effect." Exclusive study of active workers, although it may yield certain useful information, particularly on diseases of the young and those with short latency periods, is primarily a study of the healthy worker effect. Many favorable effects of the active worker will be encountered. The retirees as a whole experienced no significant excess mortality for any causes, although examination of a subgroup, the early retirees, did reveal a significant excess of deaths from diseases of the nervous system and sense organs. The retired may appear to be an ideal group for study because they usually have worked for an extended period of time, they may have experienced long-term occupational exposure and they have lived long enough to develop diseases with long latency periods; however, serious problems arise from studying only the retirees and these are discussed. The terminated group contributed 41% of the person-years, 49% of the total number of individuals and 38% of the deaths and is far too important to be omitted. Contrary to previous reports, the terminated did not demonstrate a significantly adverse mortality experience when compared with the general population, although they did not show the healthy worker effect that was seen among the active.

Long-term mortality study of oil refinery workers. I. Mortality of hourly and salaried workers

This longitudinal study examined the mortality and cancer experience of workers at the Gulf Oil refinery located in Port Arthur, Texas. The cohort was studied over a period of 41 years, from 1937 to 1978, and consisted of 16,880 employees, with an accumulation of 406,198 person-years; 4361 deaths were observed. Emphasis of this study was placed on the experience of the hourly and salaried male workers employed one day or more and those with a minimum of one year employment. The standardized mortality ratio analysis revealed generally favorable mortality experience of the refinery workers, including that of overall cancer. Statistically significant deficits in mortality were found for several cancer sites including bladder, liver, and esophageal cancer. Many of the increased cancer risks suggested in the literature were not confirmed in this study. Although bone cancer was found to be increased significantly, review of those death certificates raises questions as to the accuracy of the recording and coding of this cancer. Sample size of this study is capable of providing sufficient statistical power for the detection of a twofold increase in mortality risk for many cancers, if such risk exists.

Retrospective mortality and medical surveillance studies of workers in benzene areas of refineries

The mortality and health experiences of refinery workers employed in benzene processes or operations are described. A retrospective cohort mortality study of benzene workers employed from 1952 to 1978 revealed no excess in overall general mortality or in cancer mortality compared either with the experience of the U.S. general population or with that of an internal control group. Ascertainment of vital status was accomplished for 99% of the cohort. Recent industrial hygiene data that included 1,394 personal samples indicated that 84% of all benzene exposures were less than 1 part per million (ppm), with a median exposure of 0.14 ppm for the refinery workers, and 0.53 ppm for those in the benzene-related units. Among these workers, no deaths from leukemia were observed. A medical surveillance program for benzene workers is also described, with special emphasis on the effectiveness of laboratory screening. Evaluation of data for a 21-year period showed no significant changes in the blood indices of the workers as a group. The limited value of establishing screening guidelines without the support of epidemiological studies is discussed.

Anatomy of the healthy worker effect: a critical review

The healthy worker effect is the composite result from factors such as (1) selection of the work force, (2) changes in lifestyle accompanying employment, and (3) methodological characteristics of the standardized mortality ratio (SMR). While the choice of the general population as the comparison population is the underlying reason for this effect, no more feasible, widely accepted or "better" alternative is yet available. Much of the current understanding of the healthy worker effect has been limited to an examination of selection of the work force. The purpose of this report is to illustrate, using examples from a large cohort study, the importance of many factors other than selection. They include employment-associated benefits such as economic gain, medical insurance and lifestyle changes, the proportion of active workers, the calculation method, data completeness, length of follow-up and certain characteristics of SMR methodology. It is shown that some of the healthy worker effect is characteristic of SMR methodology and that the strength of the healthy worker effect depends on the proportion of active workers in the cohort. Furthermore, the disappearance of the healthy worker effect may be due to factors such as aging of the cohort and can be totally unrelated to the true increase in the mortality risk. In other words, its disappearance, in many instances, may be an artifact of SMR methodology.

Emergency percutaneous transtracheal ventilation (PTV)

Ventilation through a percutaneous needle catheter inserted into the trachea has been advocated for resuscitation in acute upper airway obstruction. However, the customized, prefabricated equipment proposed by others for that use is not always available. We describe a device for percutaneous transtracheal ventilation (PTV) that can be rapidly assembled using available, inexpensive hospital supplies. With this device, moderate inflation pressures and flow rates of oxygen resulted in arterial PaO2 of greater than 300 torr and PaCO2 values of approximately 40 torr in dogs. PTV may be used as a life-saving measure in cases of acute upper airway obstruction when conventional airway management is unsuccessful.

Pulmonary angiography via an indwelling four-channel Swan-Ganz catheter

An indwelling Swan-Ganz catheter was utilized for pulmonary angiography in an extremely ill patient without the necessity for a further invasive procedure. The procedure allowed prompt exclusion of pulmonary embolism as a cause of her deteriorating condition, and confirmed the diagnosis of adult respiratory distress syndrome (ARDS).

Airway maintenance in patients with long-term endotracheal intubation

Long-term endotracheal intubation in seriously ill patients is frequently complicated by nosocomial infection of the tracheobronchial tree, especially with aerobic gram negative bacilli. A further complication is drying of pulmonary secretions unless the medical gases given are humidified. The performance characteristics of humidifying system used in spontaneously breathing, intubated patients is described. This system possesses the potential to decrease infection, provides physiologic humidification without nebulization, and, by avoiding air dilution, allows the administration of a precisely regulated FIO2.