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The payload of a clinical lab in space.

Columbus would have understood the troubles that have beset the planning and development of the United States Space Station Freedom. This grand and glorious culmination of the current phase of space exploration was always an on-again, off-again program. The downturn in the U.S. economy and a reassessment of national spending priorities caused cutbacks in the ambitious project, approved in more prosperous times. Nevertheless, plans have proceeded. The latest proposals by the National Aeronautics and Space Administration (NASA) call for a leaner, trimmer, less-expensive orbiting space station than the one that was drawn in the original blueprints.

Current plans call for the basic components to be assembled in space in 1996. A scaled-down version will first be inhabited in 1999. By the year 2020 the entire space station is expected to be in place.

Even the earliest elements of the station will incorporate major contributions from clinical laboratory science. A discussion of these attributes follows.

* Zero gravity. Extensive studies are under way regarding potential effects of space flight on the cardiovascular and musculoskeletal systems, metabolic processes, and individual cells. The health of the astronauts, who are in prime physical condition, is not at issue. Scientists are more concerned about compiling laboratory data with which to evaluate physiologic changes that may occur during prolonged exposure to an environment of zero gravity.

Any lunar outpost would also have to include a health care laboratory. Some components of the putative space laboratory have already been tested in shuttle missions. Last year, scientists employed a reusable lab to evaluate potential effects on the human body of living and working in space. This activity was part of the Spacelab Life Sciences 1 (SLS-I) project, which was carried aboard the shuttle Columbia for a nine-day mission.

* Instruments. Groups of scientists have been asked to design instruments for the space station's laboratory module. Exposing workers in space to a battery of tests is desirable for determining human response to a weightless environment. Figure ~lists some concerns related to in-flight health care and research.

Modern medical diagnosis and care rely increasingly upon laboratory test results. Workers in the Freedom lab must be able to perform all assays required for diagnosis, determination and guidance of therapy, and monitoring the clinical course of medical problems occurring in space. As in hospital critical care units, the tests needed most will provide blood gas levels, common chemistries, and blood counts. Therefore, it was decided that the space station laboratory had to include at least two instruments: a chemistry analyzer and a cytometer.

* Clinical chemistry. The chemistry analyzer is needed in space not only to measure the usual physiologic changes and known effects of space on the cardiovascular and musculoskeletai systems but also changes in calcium homeostasis that can occur in such an environment. The Russian space station Mir, orbiting Earth since 1986, uses a reflectance analyzer for chemistry testing. To do the same job on Freedom, NASA planners awarded a contract for two analyzers in late 1987 to Eastman Kodak, which already produced a compact instrument that seemed capable of doing the job.

The first prototype, delivered in October 1988, uses dry-slide technology and can operate in zero gravity. A more advanced model was delivered in June 1989. The analyzer can perform 25 chemistry procedures on serum specimens and 7 on urine specimens.

The instrument occupies approximately half a cubic meter in the space station's health maintenance facility. Roughly speaking, the analyzer represents a cross between Kodak's highly automated commercial chemistry instruments and its smaller versions, such as the DT60, designed to accommodate intensive care units as well as physicians' office laboratories (POLs).

* Cytometry. About 15% of astronauts who participate in long space flights experience a loss of red cell mass. A cytometer is needed to study this loss and to note any changes in leukocytes. Alterations in white blood cells will be studied aboard Freedom as well (Figure 11).

Looking for a special instrument, NASA officials convened several meetings that culminated in a contract to design and construct a prototype. Cosponsoring these meetings was the American Cancer Society, in the expectation that technology developed to perform such studies in space would also be useful in cancer diagnosis and research on Earth. In January 1990, NASA issued a request for proposal (RFP) for the cytometer, stipulating the following characteristics:

[paragraph] Size. Because square footage devoted to equipment in the space station will be extremely limited, the cytometer must be as small and lightweight as possible; in fact, it must be literally smaller than a breadbox.

[paragraph]Environment. The instrument must be able to function in an environment of zero gravity.

[paragraph]Parameters. The cytometer must perform in-flight analysis on such long-duration space flight parameters as cellular function, immunologic responses, bone metabolism (primarily bone loss), muscle atrophy, and the effects of radiation. Through telemetry, NASA should be able to use the cytometer to monitor the many aspects of the crew's health that may be adversely affected by prolonged flight. The instrument should provide data leading to studies of the effectiveness of countermeasures to prevent or ameliorate such untoward effects.

[paragraph]Research. The cytometer should address the needs of the research community for improved prevention, diagnosis, and treatment of disease, with special emphasis on cancer.

* Performance. Among the desirable elements of analytic performance by the space cytometer (Figure III), top priority will be given to calibration, standardization, and quality control. The need for microsampling is of special concern to laboratorians. Also attractive is the possibility of instituting a hybrid system that would screen for cells of particular interest. Any positive screen could trigger definitive studies of those cells. The ability to discover so-called rare events is of special interest to oncologists and to others involved in the diagnosis and treatment of cancer.

* Telemetry. One intriguing requirement for the cytometer is that it produce data in a form transmissible to the ground for analysis. Testing data will be acquired by the onboard computer and sent to a receiving station on Earth, where it will be analyzed. Adjustments for calibration and for realignment of optics and fluid components will be made remotely. Internal diagnostic programs will flag any mallunctions for remote correction.

Having established priorities for the cytometer, NASA issued an RFP in January 1990. Testing of a prototype is expected to begin this year.

* Terrestrial applications. The priorities established for the Freedom cytometer will clearly be of great interest to clinical pathologists, hematologists, and oncologists. If such instruments were generally available, they would go a long way toward solving problems that arise daily in hematology laboratories. Are blast cells circulating in the peripheral blood? Have all malignant cells been purged from the autologous bone marrow transplant? Microbiologists are likely to have questions of their own.

Imagine the capabilities of a state-of-the-art space cytometer applied to problems common in terrestrial labs. A patient specimen is placed in a hand-held sampling module for glucose or hemoglobin analysis. The data stream, such as optical density with patient bar code identification, is sent via telephone lines to the central laboratory for detailed analysis. After evaluation, the report is sent directly to the patient's bedside. Data are entered into the patient's record and billing is generated. Perhaps experiments with the space lab will lead to such attractive solutions.

* Decentralized. Quality control, documentation, and billing are aspects of bedside testing that remain problematic in many hospitals. Telemetry as it will be pioneered in the Freedom cytometer is expected to assist in those areas.

In a remote system, only specimen collection and bedside analysis must be performed by physicians, nurses, and other health care workers, and even then with minimal orientation. One decentralized testing model includes not only many traditional support and administrative services but also routine chemistry and hematology assays. A program called World Class Healthcare was proposed by Kodak in alliance with Anderson Consulting, Chicago, in 1989.

Such a plan sends shivers down the spines of longtime laboratorians who learned the hard way about the dangers that prevailed in the old-fashioned ward laboratories. Many of us remember the dirty microscopes, the slide coverslips substituted for hemocytometer coverglasses, and the Gram-stained sinks and floors that would not pass inspection today.

Why would anyone want to return to those methods? It's important to note how greatly instrumentation has changed. Now, highly refined instruments in coronary care units do all cardiac drug testing on site. Hand-held glucose and hemoglobin analyzers provide Stat results of diagnostic caliber at the bedside and even in the patient's home. Instruments that measure activated coagulation time for monitoring heparinization during cardiac surgery are in place in operating rooms throughout the country.

Instrument manufacturers have designed and built instruments capable of providing reliable data when properly used. Studies indicate that a number of these analyzers can be operated adequately by nonlaboratorians. The same would presumably be true for NASA's chemistry and hematology analyzers. We have come a long, long way from those Gram-stained sinks.

What about calibration, QC, data reporting, and other aspects of testing that have increased in importance? The NASA initiative may satisfy both clinicians and laboratorians. According to current plans, studies on the Freedom will be done at the point of care. Analysis, record keeping, calibration, QC, and data reporting and storage will be accomplished centrally.

Earthbound health care facilities don't need the complex telemetry required on the space station. It would be relatively simple to use telephone lines or an ordinary alternating-current (AC) electrical system in a phase-locked loop circuit. Some radio frequencies already are being used for real-time transfer of data. Laboratory information seems eminently suitable for such an application.

* Technology transfer. Remote testing will permit the clinical laboratory to monitor the performance of bedside instruments. Monitoring internal checks continually will permit laboratorians to identify and remedy problems quickly. Record keeping will be simplified. Data collected in the lab will be more readily available for the study of trends.

A remote system such as the one about to be pioneered in Space Station Freedom may hold the key to certain nagging problems in laboratory medicine. With turnaround time no longer an issue, highly trained laboratorians could focus their energy on problems requiring their attention and expertise. The results would become even more useful for patient care.

The author is professor of pathology and director, laboratory quality improvement program. Duke University Medical Center, Durham, N.C. He extends special thanks to Gerald R. Taylor, Ph.D., NASA science manager for Space Station Freedom, for sharing information about the space station instrumentation and for reviewing this article. The author also acknowledges Bruce McKinley, Ph.D., of Krug Life Sciences for discussions of chemistry

instrumentation for the space station and of the lunar outpost. The author thanks NASA and the American Cancer Society for inviting him to participate in this project.
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Author:Koepke, John A.
Publication:Medical Laboratory Observer
Article Type:Cover Story
Date:Jul 1, 1992
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