10.1.15 Introduction

Vital signs is one of the first areas where there is a need for a single, global vocabulary to allow for ubiquitous access and re-use. Particularly with the use of wearables by patients where they want to/need to share information from those devices. To meet this need there must be a consistent vocabulary and a common syntax to achieve semantic interoperability. The FHIR Vital Signs profiles set the minimum expectations for the Observation resource to record, search and fetch the vital signs associated with a patient. These include the "primary" vital signs of heart rate, respiratory rate, blood pressure (systolic and diastolic) and body temperature, plus additional measurements such as body height, body weight, BMI and oxygen saturation. Support for basic mandatory searching of resources is defined below in the Quick Start section. When a FHIR implementation supports any of the vital signs observations listed below, the implementation SHALL conform to the vital signs base profile and also the profile for the specific vital sign observation.

[Note: These requirements were originally developed, balloted, and published in FHIR DSTU2 as part of the ONC sponsored Data Access Framework (DAF) project and were subsequently updated to define the minimum mandatory conformance requirements needed for accessing patient data as defined by the Argonaut pilot implementations.]

10.1.16 Scope and Usage

Example Usage Scenarios:

The following are example usage scenarios for this profile:

• Query for vital signs of a particular patient

10.1.16.0.0.1 Mandatory Data Elements and Terminology

The following data-elements are mandatory (i.e. data SHALL be present). These are presented below in a simple human-readable explanation. Profile-specific guidance and valid examples are provided as well. Note that many of the examples capture more than the minimum required. The links to the Profile Definitions provide the formal views of the profile content, descriptions, mappings and the StructureDefinitions in JSON and XML.

The Vital Signs Base profile requires that each Observation must have:

1. a status
2. a 'category' code of 'vital-signs'
3. an additional "interoperability category" LOINC code in the 'category' element which specifies the high level (methodless) category for what is being measured
   • The code for the actual measurement is specified in the 'code' element. This code (which may be from LOINC or a different code system) typically will be more specific than the "interoperability category" LOINC code.
4. a patient
5. a time indicating when the measurement was taken
6. a numeric result value and standard UCUM unit which is taken from the Unit Code column in the table below.
   • note: if there is no numeric result then you have to supply a reason

10.1.17 Formal View of Specific Vital Signs Profile Content

• The table below represents the set of vital sign concepts and the profiles that have been defined for representing them in the Observation resource, along with the associated required high level (methodless) LOINC "interoperability category" codes, and the UCUM units of measure codes that are used for representing the vital signs observations. These terminology bindings are extensible and require that when a system supports any of these vital signs concepts, they must represent them using these codes. In addition, if you have a blood pressure observation, you must have both a systolic and a diastolic component, though one or both may have dataAbsentReason instead of a value.
• The first column of this table links to the formal views of the individual profile for each vital sign.
• Other profiles may make rules about which vital sign must be present, or must be present as part of a panel, or may expand the list to include other vital signs.

Profile Name	"Interoperability Category" (LOINC)	LOINC Name and Comments	UCUM Unit Code	Examples
Vital Signs Panel	85353-1	Vital signs, weight, height, head circumference, oxygen saturation and BMI panel - It represent a panel of vital signs listed in this table. All members of the panel are optional and note that querying for the panel may miss individual results that are not part of the actual panel. When used, Observation.valueQuantity is not present; instead, related links (with type=has-member) reference the vital signs observations (e.g. respiratory rate, heart rate, BP, etc.). This code replaces the deprecated code 8716-3 - Vital signs which is used in the Argonaut Data Query Implementation Guide.	-	Vital Signs Panel Example
Respiratory Rate	9279-1	Respiratory Rate	/min	Respiratory Rate Example
Heart rate	8867-4	Heart rate - To supplement this vital sign observation, 8887-2 - Heart rate device type MAY be included as an additional observation.	/min	Heart Rate Example
Oxygen saturation	2708-6	Oxygen saturation in Arterial blood - This code replaces 59408-5 Oxygen saturation in Arterial blood by Pulse oximetry as the "interoperability category" code (but MAY be used in Observation.code).	%	Oxygen Saturation Example
Body temperature	8310-5	Body temperature - To supplement this vital sign observation, 8327-9 - Body temperature measurement site (oral, forehead, rectal, etc.) and 8326-1 -Type of body temperature device MAY be used as additional observations.	Cel, [degF]	Body Temperature Example
Body height	8302-2	Body height - The more specific code 8306-3 -Body height - lying (i.e., body length - typically used for infants) MAY also be used in Observation.code.	cm, [in_i]	Body height Example
Head circumference	9843-4	Head Occipital-frontal circumference	cm, [in_i]	Head Circumference Example
Body weight	29463-7	Body weight - The more specific code 8352-7 - Clothing worn during measure and 8361-8 - Body position with respect to gravity MAY also be used in Observation.code.	g, kg,[lb_av]	Body Weight Example
Body mass index	39156-5	Body mass index (BMI) [Ratio]	kg/m2	Body Mass Example
Blood pressure systolic and diastolic	85354-9	Blood pressure panel with all children optional - This is a component observation. It has no value in Observation.valueQuantity and contains at least one component (systolic and/or diastolic). To supplement this vital sign observation, 8478-0 - Mean blood pressure, 8357-6 - Blood pressure method, 41904-4 - Blood pressure measurement site, 8358-4 - Blood pressure device cuff size, 41901-0 - Type of blood pressure device MAY be used as additional observations.	-	Blood Pressure Example, Blood Pressure Example with missing Diastolic measurement
Systolic blood pressure	8480-6	Systolic blood pressure - Observation.component code for a blood pressure Observation	mm[Hg]	Blood Pressure Example
Diastolic blood pressure	8462-4	Diastolic blood pressure - Observation.component code for a blood pressure Observation	mm[Hg]	Blood Pressure Example

10.1.18 Quick Start

Below is an overview of required search and read operations

Clients

• A client has connected to a server and fetched all of a patient's vital signs by searching by category using GET [base]/Observation?patient=[id]&category=vital-signs.
• A client has connected to a server and fetched all of a patient's vital signs searching by category code and date range using GET [base]/Observation?patient=[id]&category=vital-signs&date=[date]{&date=[date]}.
• A client has connected to a server and fetched any of a patient's vital signs by searching by one or more of the codes listed above using GET [base]/Observation?patient=[id]&code[vital sign LOINC{,LOINC2,LOINC3,...}].

• A client SHOULD be capable of connecting to a server and fetching any of a patient's vital signs searching by one or more of the codes listed above and date range using GET [base]/Observation?patient=[id]&code=[LOINC{,LOINC2...}]vital-signs&date=[date]{&date=[date]}.

Servers

• A server is capable of returning all of a patient's vital signs that it supports using GET [base]/Observation?patient=[id]&category=vital-signs.
• A server is capable of returning all of a patient's vital signs queried by date range using GET [base]/Observation?patient=[id]&category=vital-signs&date=[date]{&date=[date]}.
• A server is capable of returning any of a patient's vital signs queried by one or more of the codes listed above using GET [base]/Observation?patient=[id]&code[vital sign LOINC{,LOINC2,LOINC3,...}].

• A server SHOULD be capable of returning any of a patient's vital signs queried by one or more of the codes listed above and date range using GET [base]/Observation?patient=[id]&code=[LOINC{,LOINC2...}]vital-signs&date=[date]{&date=[date]}.

• A server has ensured that every API request includes a valid Authorization token, supplied via:Authorization: Bearer {server-specific-token-here}
• A server has rejected any unauthorized requests by returning an HTTP 401 Unauthorized response code.

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10.1.18.0.1 GET [base]/Observation?patient=[id]&category=vital-signs

Example: Search for all Vital Signs measurements for a patient

GET [base]/Observation?patient=1186747&category=vital-signs

Support: Mandatory to support search by category code.

Implementation Notes: Search based on vital sign category code. This search fetches a bundle of all Observation resources with category 'vital-signs' for the specified patient (how to search by reference) and (how to search by token). The table above is the minimum set, additional vital signs are allowed.

Response Class:

• (Status 200): successful operation
• (Status 400): invalid parameter
• (Status 401/4xx): unauthorized request
• (Status 403): insufficient scope

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10.1.18.0.2 GET [base]/Observation?patient=[id]&code=[vital sign LOINC{,LOINC2,LOINC3,...}]

Example: Search for all heart rate observations for a patient:

GET [base]/Observation?patient=1186747&code=8867-4

Example: Search for all heart rate, respiratory rate and blood pressure observations for a patient:

GET [base]/Observation?patient=1186747&code=8867-4,9279-1,85354-9

Support: Mandatory to support search by vital sign LOINC(s) listed above.

Implementation Notes: 1)Search based on vital sign LOINC code(s). This fetches a bundle of all Observation resources for specific vital sign(s) listed in the table above for the specified patient (how to search by reference) and [how to search by token)]. 2) The "code" parameter searches only Observation.code. For example when fetching blood pressures the resource will be only be returned when the search is based on 85354-9(Systolic and Diastolic BP). Using the component codes 8480-6(Systolic BP) or 8462-4 (Diastolic BP) will not return the resource . In order to search both Observation.code and Observation.component.code in a single query, use the "combo-code" search parameter.

Response Class:

• (Status 200): successful operation
• (Status 400): invalid parameter
• (Status 401/4xx): unauthorized request
• (Status 403): insufficient scope

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10.1.18.0.3 GET [base]/Observation?patient=[id]&category=vital-signs&date=[date]{&date=[date]}

Example: Find all the blood pressures after 2015-01-14

GET [base]/Observation?patient=555580&code=85354-9&date=ge2015-01-14

Support: Mandatory to support search by category code and date

Implementation Notes: Search based on vital sign category code and date. This fetches a bundle of all Observation resources with category 'vital-signs' for the specified patient for a specified time period (how to search by reference) and (how to search by token).

Response Class:

• (Status 200): successful operation
• (Status 400): invalid parameter
• (Status 401/4xx): unauthorized request
• (Status 403): insufficient scope