| Reliability and stability of the results |
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| The results are functional and the reliability is closer to the physiological parameters measurement such the laboratory tests, the blood pressure, oxymetry,body temperature and others......... |
| EIS system values of reference was determined from clinical investigations. |
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| The analytical variation reflects the inaccuracy of the method used: one estimates this by analyzing the test several times. |
For EIS system, the follow up of a subject without treatment during 1 year, was made for more 100 cases, with physiological more modification that the follow up of other devices with a measuring function of physiological parameters. |
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The intra-individual variation is estimated by the repetition of the examination to the same individual. The clinical investigations at the Botkin hospital, made it possible successively to record the patients 3 times. No notable modification.
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| An experiment of Dr. Richard Clement was carried out, by recording 2 patients on 2 different computers of mark and in 2 different geographical places. No notable modification. |
| The inter-individual variation estimates by the average values of several individuals and is influenced by variables such as age and gender. |
| The EIS system takes in to account age, gender, weight and height in the scale measurement by applying a mathematical formula with a empiric coefficient issue of a patients'database with more 20000 measurements. |
| This calibration is carried out automatically by the software after recording of the patient’s data. |
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Its specificity and its sensitivity
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| The reproducibility of the EIS system |
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| The functional parameter of the human body, are dynamic and change according to some reference values. |
| The reproducibility of the EIS system results is the same of the reproducibility of the measure of the functional physiologic parameters. |
| For example measurement of arterial pressure, laboratory test, oximetry, and others |
| Therefore 2 examinations even close to each other, cannot give exactly the same result in physiological parameters and the statistic analysis program, can change the order of the main risk. |
| The utilization of the EIS system does not require a lot of successive examinations or on the same day |
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Therefore just like in a blood pressure test the functional estimation will be made by dynamic evaluation of the measurements.
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| Factors of variation of the EIS results |
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Interpretation of the results
Limits of decision:
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The interpretation of an EIS scan must not be based only upon a comparison between the result(s) and the reference values provided by the scan. Interpretation also requires a definition of physiological limits. On the other hand, physiological limits of decision fluctuate according to the objectives: imperatively confirm the diagnosis of structure (imagery)
- Established diagnosis
- Follow-up of the patient
- Diseases considered
- Possible therapies
- Prevalence
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So, it is impossible to make the interpretation of the EIS system without the clinical context
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Just like laboratory tests, the interpretation of the EIS requires that the user has medical knowledge of adequate references and a list of variables which can modify the results. (See factor of variation)
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The following specific issues need to be understood and respected if one is to properly interpret the results of an EIS scan:
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| 1. The results obtained by the EIS system should not be used imperatively to confirm nor deny laboratory tests, the results of imagery devices, or an electrical activity recording device. Each medical examination or evaluation has its own specificities and results on the same organ can be different according to the technique used. EIS scanning brings new elements of a complementary nature such as physiologic tissue and micro circulation parameters as well as the biochemical values of the interstitial fluid. |
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2. Biochemical values, EIS and Laboratory tests: further comments
Table 1 shows the differences in concentration of the biochemical values for each compartment.
The results of biochemical interstitial values and laboratory tests (blood) can be completely different for 2 reasons:
- The interstitial fluid is stagnant
- The measurement of the biochemical interstitial values represent the pool of the substance because the interstitial fluid is 4 time higher in volume than the vascular system and therefore less sensible to the water variation
These results are complementary.
The pH values are different, (i.e. than arterial blood) because interstitial fluid does not have the main blood buffering elements (such as Haemoglobin and proteins). The acid base balance of interstitial fluid is regulated by the cells’ activity and the electrolytic balance between the extra and intracellular medium.
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| 3. The modeling is a representation of the organs as well as the physiopathology of interstitial fluid which traverses them. The physiopathology of interstitial fluid will be a direct reflection of the cellular activity of these organs. EIS does not give information about the physical structure of organs.. |
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4. According to the results of the tissues parameters, microcirculation and inverses problems issues from clinical tests the software propose some statistical possibilities of diseases or dysfunction with a specificity and a sensitivity. These possibilities are not diagnostic, but screening or help for regulate more specific and sensitive supplementary examinations.
These possibilities are not available for a patient under medications (drugs or chemotherapy, radiotherapy, surgery). In this case the statistical functional risk analysis is a follow up of effects of these therapies.
The strong point of the EIS system is the follow up and the early visualization of the effects of any therapy.
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5. The EIS device provides a lot of results, but for the interpretation of cases, you do not need all the data. The EIS device is a modeling of the human body and perhaps my point will be better understood if we make a comparison with another type of modeling, the GPS (Global Positioning Service).
GPS is a modeling allowing one to find the specific directions about how to get to a specific destination. To use a GPS, you must first input both the departure address and the destination address. For the EIS system, the interpretation requires the same information: the departure address is the clinical context (check up, known pathology, symptoms, any treatment in progress, antecedents etc.), the destination address is the goal you wish to achieve for the client and what parameters you need to check in relation to the departure address (clinical context).
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