SREDSTVA IZMERENIY of medical prescription

From Big Medical Encyclopedia

MEASURING INSTRUMENTS of medical prescription — the technical means having rated metrological characteristics and used for definition of values of physical quantities by practical consideration. To S. and. the measures reproducing physical quantities of given size, measuring devices and converters, and also consisting of them measuring installations and systems belong.

S. applied in healthcare institutions all and. are divided into the means of all-economic (all-technical) appointment used in all industries of the national economy and special. To all-technical S. and. universal S. belong, e.g., and. for measurement of weight (scales and weights), electrical and radio engineering quantities (arrow and digital ampermeters and voltmeters, oscillographs, generators), temperature (a lab. thermometers), pressure in vessels (technical manometers and manovakuummetra), optical sizes (photoelectrocolorimeters, refractometers, spectrophotometers, dioptrimetra), etc. These S.' use and. in healthcare institutions it is allowed on condition of their compliance to the norms and rules established to M3 of the USSR. The majority of measurements in medicine can be taken only by means of S. and., the M3 of the USSR which are specially created according to the requirement specification having medical prescription and, as a rule, not counted on use in other industries of the national economy, science and technology; with nek-ry constructive changes they can be applied only to measurements on animals in biology and veterinary science, and also in the laboratories conducting researches in agriculture or in the field of environmental control.

Depending on design features and a way of use of measuring information distinguish the following main types of S. and. medical appointments. 1. The measure of medical appointment — reproduces the physical quantity of one size (an unambiguous measure), napr, the standard sample of chemical substance of a gemog-lobintsianid which is a measure of spectral optical density, the «artificial ear» device which is a measure of acoustic conductivity etc. or a number of the physical quantities of the same name of various size (a multiple-valued measure, set died), napr, sets of trial eyeglass lenses — measures of optiko-geometrical sizes, height meters — measures of the linear sizes, etc. 2. The measuring device of medical appointment — develops a signal of measuring information in the form available to direct perception by the observer (the electrocardiograph, a hand dynamometer, the sphygmomanometer, etc.). 3. The measuring converter of medical appointment — its signal of measuring information is convenient for further transformation, processing, storage, but does not give in to direct perception by the observer, napr, the signals from the intragastric rn-probe, the sensor of temperature or pressure demanding use of secondary measuring means. 4. Measuring installations and measuring systems of medical appointment — functionally integrated S.' set and. medical appointments, all-technical S. and. and auxiliaries; in installations signals of measuring information are perceived directly by the observer (polygraphs, monitor installations), and in systems these signals are developed in the form convenient for after-treatment (information medical systems and complexes). 5. Medical dosers — a combination of constant or variable measures to auxiliaries of delivery of measured amounts of substances (the pharmaceutical doser, an injektor with dosage measurement, a medical micropipet).

On range of application of S. and. medical appointments divide into the following groups: for definition fiziol. indicators and functional diagnosis; for a lab. analyses biol. tests; for a dignity. - a gigabyte. control of the environment and working conditions; for control of doses of therapeutic and surgical power influences.

Depending on belonging to a certain field of physics or chemistry all physical quantities in metrology can be carried to one of types of measurements: mechanical, linearly - angular, electric, radio engineering, optiko-physical, acoustic, tep-lofizichesky, physical and chemical and biochemical, to measurements of parameters of ionizing radiation.

Within each group C. and. medical appointments are classified by character of the measured physical quantity (table).

Constant complication of S. and. medical appointments, use in traditional medical metering devices of the new principles of transformation of primary measuring information does ambiguous similar classification in cases when the studied medicobiological size and directly measured physical quantity treat different types. Most often it concerns indirect measurements. So, in a pletizmografiya parameters of a krovenapolneniye of bodies, vessels or body parts are investigated, i.e. mechanical measurements are performed, however the measuring converters used at the same time have indisputable signs of accessory to optical (fotopletizmografiya) or to electric (reopletizmografiya) devices; in researches of a hemodynamics of blood to a similar situation brings use of ultrasonic Doppler, electromagnetic and radio isotope converters, and into a lab. devices — spektrofotometrichesky converters.

On S.'s design and. medical appointments can be autonomous and built-in. Autonomous S. and. usually measure parameters of an organism, make laboratory and a dignity. - a gigabyte. measurements. Page and. medical appointments for control of doses of influences most often represent the devices which are built in the physiotherapeutic equipment. Usually S. are also built-in and. in the equipment for substitution of functions, bodies and systems; measuring instruments of biopotentials and a rhythm in electrostimulators, measuring instruments of speed of a blood-groove in cardiopulmonary bypasses, etc.

On range of application and their place in the testing scheme C. and. medical appointments are divided on the workers applied to measurements of the sizes of units which are not connected with transfer and exemplary — for checking of S. workers by them and. As exemplary are applied: S. workers and., the model S. which are specially adjusted for the purpose of obtaining higher metrological characteristics, specially developed and., to-rye usually are not used for direct working use; standard samples of structure or properties biol. tests. In all cases the specified means shall be certified and approved as exemplary.

Metrological properties C. and. are described by a complex of the normalized metrological characteristics, to-rye the measurements established in the State system of ensuring unity are chosen from among. The main objective of this choice — to provide a possibility of assessment by means of this S. and. the actual error of measurement in real service conditions and the modes of use with the set confidential probability. Proceeding from the specified principle, a complex of the normalized metrological characteristics of S. and. generally create of characteristics of the converter or output size, statistical estimates static and dynamic (in case of need) systematic and accidental making errors, parameters or functions of influence of external factors on S.'s errors and., the additional metrological characteristics and not informative parameters of an output signal depending on specific types of S. and.

In the USSR by order of M3 of the USSR and the State committee of the USSR on standards of July 5, 1979 measuring instruments of medical appointment are subject to metrological supervision in the standard forms. State tests of S. and. medical appointments before statement them on production (the state acceptance tests) are carried out jointly by parent organization metrological health service (see) and leader metrological in-volume of Gosstandart. By results of the state acceptance and subsequent medical tests by the solution of Gosstandart of S. and. medical appointments are entered in the State register of measuring instruments, and the decision M3 of the USSR allows to use in medical practice, to industrial production or import. Bodies of metrological health service take part in the state check tests which are carried out in a process of manufacture by territorial authorities of Gosstandart. S.'s checking and. medical appointments at release from production it is carried out in the form of the state primary checking, and at release from repair, at storage and operation — in the form of periodic departmental checking by bodies of metrological health service. Frequency of checking at storage and operation is defined by metrological reliability and intensity of use of S. and. medical appointments. On average one checking a year is established. It is carried out in strict accordance with the normative documents on methods and means of checking coordinated with metrological in-volume of Gosstandart and service of hl. metrologist of M3 of the USSR.

See also Metrology , Standardization .


A. N. Grishin, R. I. Utyamyshev.