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Class steward is Patient Care
For many materials, the individual thing has no relevance. Especially continuously divisible forms come only in “amounts” rather than as individuals. There is a specific class of physical quantities that can be used for amounts, count (number), amount of substance, mass, and volume. This class of physical quantities is called “extensive” quantities. A quantity is called extensive if it can be added up (if it is additive.) For example, if you have 1 gallon of water and you add another gallon of water, you wave two gallons of water, since volume is an additive quantity. By contrast, if you have one gallon of Glucose 5% and add to it another gallon of Glucose 5% you still have Glucose 5%, thus, mass fraction is not an additive (extensive) kind of quantity.
Only extensive quantities are permitted as elements of the Material.qty set. Typically the kinds of quantities shown in Table 34 will occur. Extensive quantities are simpler to deal with than intensive quantities. Extensive quantities are never fractions or ratios, no denominator can cancel out the units of a numerator, and therefore, with extensive quantities we can conclude the kind of quantity from the unit of measure.
Table 34: Kinds of quantities for amounts of material Kind of quantity Typical Unit Forms Examples Number 1 solid Material that is large enough that is can be counted ("eaches") Mass 1 g liquid, solid Tissue, chemical substances, food. Amount of substance 1 mol all Chemical substances, small particles. Volume 1 L liquid, gas Chemical substances in liquid and gas state. Amorphic tissue. Length 1 m solid Long material measured in length, e.g., tape, pipes, hose, etc. Area 1 m2 solid Flat material measured in area, e.g., covers, foils, etc. Energy 1 J, 1 kcal solid, liquid Chemical substances, especially food. Catalytic amount 1 kat, 1 U, 1 i.U. all Enzymes and other chemical substances having catalytic activity. Radioactivity 1 Bq, 1 Cu all Radioactive substances. Reaction equivalent 1 Eq all Ionized chemical substances measured through titration. Deprecated, use proper amount of substance instead.
The Material.qty attribute permits to convey a collection of physical quantities. This collection feature must be used in the following way. When the set contains more than one quantity, the quantities must have different units. Furthermore, all quantities in the set must denote an equivalent amount. For example, for the material Glucose, we may specify an amount as the mass of 1 g. If we also want to specify the amount in amount of substance (moles) we must specify the equivalent of 1 g Glucose in mole, which is 5.556 mmol. For another example, if we specify the amount of a material Water as 1 L, and we want to provide a mass, the mass must be the mass of 1 L water, which is 1 kg.
OpenIssue: This name must be made consistent if the name of the Material class changes.
The role type may be used in the opposite direction.
For example, instead of listing a material instance representing a mixture and subordinate to it mentioning the ingredients as target material instances, one can use one ingredient and subordinate to it mention the mixture in which it happens to exist. This is the common way of thinking of pharmaceuticals. In most pharmaceuticals, we have one main ingredient which we consider “therapeutically active” and which we mention, although we know that this substance always comes as an ingredient of a mixture containing diluents, stabilizers, preservatives, flavors and colors. This active ingredient can then be specified as the top material instance ->inverted ingredient -> mixture -> ingredient -> other ingredients.
Another notable example for inversion of the relationship type is for containers. The content relationship type allows one to first list a container (e.g. package) and then provide a list of content as subordinate (target) material. In other cases, one wants to mention the material first and by the way describe it being contained in a container. Therefore, when the content is the important thing and the container just goes with it (e.g., for most medications,) one will use the inverted content link.
Some containers have discrete positions in which content may be located. Depending on the geometry of the container, the position may be referenced as a scalar ordinal number, or as a vector of ordinal numbers (coordinates.) Coordinates always begin counting at 1.
Some containers may have customary ways of referring to the positions. Take a checkboard, for example, in which rows are specified A-H and columns specified 1-8. In these cases, the non-numeric coordinate must be converted into a numeric. The in absence of any specific regulation for a specific container type, the rule of thumb is that the coordinate that is changed earlier is positioned first. For the checkboard example, this means that the columns are changed or traversed first. When you start placing the figures in the start position, you chiefly align them in the columns, and only then you start moving them ahead in rows (and columns too.)
For an automated blood chemistry analyzer, with a square shaped tray, this means that the first coordinate is the one in which direction the tray moves at each step. Whereas the second coordinate is the one in which the tray moves only every 10 (or so) steps.
As a final example, the positions on a computer screen that works in usual left-to-right and top-to-bottom direction, the columns would be the first coordinate and the lines would be the second coordinate. (Note however, that this is just an example to clarify the rule. It does not mean that a character displayed on a screen would be an instance of the Material class. In fact, it’s immaterial.)
This attribute specifies how much of the target material is contained in the source material of a relationship. For example, if a box contains 10 eggs, the box is the relationship source is the box and the relationship target is the egg, where the relationship quantity is 10. For mixtures with multiple ingredients, the relationship quantities specify the relative amounts of the ingredients in the mixture (proportion.)
The quantity must be a quantity that specifies an “amount” (refer to Table 34 in Section 2.7.1.10). The amounts specified as the proportion quantity for each ingredient are taken to be numerators over the same denominator. For example, D5W is a mixture consisting Water (H2O) and 5% (= 50 g/L) Glucose (Glc.) The proportions can be either of the following pairs: H2O:1 g + Glc:50 mg; H2O:1 L + Glc:50 g; H2O:500 mL + Glc:25 g; or any combination that amounts to the same concentration of Glucose in Water.
Note that the value of the proportion quantity does not matter as long as the proportion between the ingredients of a substance is kept invariant. If, for example, we specify D5W as having ingredients 500 mL of H2O and 25 g of Glucose this does not mean that D5W could only be dispensed in multiples of 500 mL.
For some transient relationships between material one can specify a time in which the relationship is valid using the Material_relationship.tmr attribute. As with any interval of points in time, a start time, an end time, or a just a duration may be specified.
Material relationships can be of different types, i.e., may express different kinds of relationships. The relationship concepts are exhaustively defined in USAM specification Table 35, that is. The concepts of that table must be used.
Every relationship type implies certain roles for the material at each side of the relationship. The notion of roles in a material relationship is very similar to material roles as defined in Section 2.8 below. Where in Table 35 the roles are so generic that they are not represented as a material role class in the model, that generic role name is printed in italics. Role names in upright font refer to the same concept as represented by the material role class of the same name. In general a material filling that role should be accompanied by the detail defined in the role class, but it is not an absolute requirement. For example, if a material is taken as a container but none of the container-specific attributes are applicable, the instance of the Container role class need not be present.