Definition: There are many situations, such as the creation of an order for a group of intravenous (IV) solutions, where the sequence of the individual intravenous solutions (each an service in itself) needs to be specified, e.g., hyperalimentation with multi-vitamins in every third bottle.
There are other situations, where part of the order's instructions contains a results condition of some type, such as "PRN pain." There is currently a free text "condition" component of ORC-4-quantity/timing which allows any condition to be specified. However, to support a fully encoded version of order sequencing, or results condition, we have defined in the following paragraphs a 10th component of ORC-4-quantity/timing.
The sequencing conditions supported by this 10th component are based on the completion of a predecessor service.
Components beyond the 10th are reserved for future use in specifying multiple conditions to be evaluated before the execution of the order. Any such future specifications will be upwardly compatible from the current quantity/timing definitions.
Note: If the 10th component is present, the 7th component (condition) will be considered as a text "note" to be displayed on the order. That is, no attempt will be made to interpret it as part of the machine-readable sequencing specification. |
To define a sequence condition, the 10th component of the quantity/timing field component is divided into the subcomponents described in Figure 4-7.
Figure 4-7. Subcomponents of order sequences
Subcomponent |
Contains |
Notes |
1 |
Sequence/Results Flag |
S for sequence conditions; C for cyclical; R is reserved for possible future use. The C will be used for indicating a repeating cycle of orders; for example, individual intravenous solutions used in a cyclical sequence (a.k.a. "Alternating IVs"). This value would be compatible with linking separate orders or with having all cyclical order components in a single order. Likewise, the value would be compatible with either Parent-Child messages or a single order message to communicate the orders sequencing |
2, 3 |
Placer Order Number, first two components |
Required/Optional: Contains the first two components of the placer order number: entity identifier (ST) and namespace ID (IS) (respectively). Uses two subcomponents since the place order number is an EI data type. We have not defined sub-subcomponents in HL7. |
4, 5 |
Filler Order Number, first two components |
Required/Optional: Contains the first two components of the filler order number: entity identifier (ST) and namespace ID (IS) (respectively). Uses two subcomponents since the place order number is an EI data type. We have not defined sub-subcomponents in HL7. |
6 |
Sequence Condition Value |
The acceptable condition values have the form commonly used in project planning methodologies: |
<one of "SS", "EE", "SE", or "ES"> +/- <time> |
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The first letter stands for start (S) or end (E) of predecessor order, where the predecessor is defined by the placer or filler order number in subcomponents 1,2 or subcomponents 3,4. |
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The second letter stands for the start (S) or end (E) of the successor order, where the successor order is the order containing this quantity/timing specification. |
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The time specifies the interval between the predecessor and successor starts or ends (see following examples). |
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Where <time> is defined as: S<integer> do for <integer> seconds M<integer> do for <integer> minutes H<integer> do for <integer> hours D<integer> do for <integer> days W<integer> do for <integer> weeks L<integer> do for <integer> months |
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7 |
Maximum Number of Repeats |
The maximum number of repeats to be used only on cyclic groups. The total number of repeats is constrained by the end date/time of the last repeat or the end date/time of the parent, whichever is first. |
8, 9 |
Place Order Number, last two components |
Required/Optional: Contains the last two components of the placer order number: universal ID (ST) and universal ID type (ID) (respectively). Uses two subcomponentsn since the place order number is an EI data type. We have not defined sub-subcomponents in HL7. |
10, 11 |
Filler Order Number, last two components |
Required/Optional: Contains the last two components of the filler order number: universal ID (ST) and universal ID type (ID) (respectively). Uses two subcomponentsn since the place order number is an EI data type. We have not defined sub-subcomponents in HL7. |
Use notes:
Suppose the following:
The predecessor order is defined by the OE1000&OrdEnt as the placer order number, in subcomponents 2 and 3 of component 10 of ORC-4-quantity/timing.
The successor order, this order, has the placer order number OE1001^OrdEnt in the ORC segment.
The following sequence condition values have the following meanings:
ES + 10M |
The finish time of OE1000&OrdEnt (predecessor) plus 10 minutes defines the start time of the successor, OE1001^OrdEnt (this order); i.e., start this order 10 minutes after the completion of its predecessor. |
SS - 10M |
The start time of the predecessor minus 10 minutes defines the start time of this order; i.e., start this order 10 minutes before its predecessor. |
For the special case where there is a cycle of orders that must be repeated, the first order to be executed will have a "sequence condition value" whose first character must be an asterisk (*). The last order to be executed may have a "sequence condition value" whose first character must be a pound sign (#).
Example:
*FS+10M |
translates to: execute this order the first time without evaluating the condition specified in the 10th component; but repeat only its execution when the specified external order's start or finish date/time has met this condition. This specification generates a repetition of the order for each iteration of the cycle. |
Note: This requires that the ordering application be able to specify the placer order number of the last order in the cycle in the first order's quantity/timing specification. |
To implement a cyclic group of four IV orders, using the parent/child paradigm, the parent specifies a custom group of IVs, and the following occurs:
ORC-4-quantity/timing of the second child order specifies that it follows the first child order.
ORC-4-quantity/timing of the third child order specifies that it follows the second child order.
ORC-4-quantity/timing of the fourth child order specifies that it follows the third order.
To repeat the group of four child orders in a cyclic manner, the following occurs:
ORC-4-quantity/timing of the first child order specifies that it is to be executed once without any dependence on the completion of other orders.
Its second execution follows the completion of the fourth order. See example in Section 4.8.16.2, "Custom IV example."
This scheme allows the following to be tracked:
The status of the whole group of orders to be reported back at the level of the parent order.
The status for each individual IV order by following the status of the corresponding child order.
Separate Orders example:
The same group of orders can be sent as a group of four orders (without a common parent), linked only by the data in their quantity/timing fields. In this case, there is no convenient HL7 method of transmitting the order status of the group as a whole without transmitting the status of each of the four separate orders.
Cancellation/discontinuation/hold order control events:
This logic implies the normal execution of the referenced predecessor order. Thus a cancel (or discontinuation or hold) of a predecessor order implies the cancellation (or discontinuation or hold) of all subsequent orders in the chain.
If the referenced order has been canceled (or discontinued or held), the current order inherits that same status.
In the case of hold, the removal of the hold of the predecessor implies a removal of the hold for the given order (which can then be executed according to the specification in the 10th component).