US Veterans Health Administration FHIR Map Set Implementation Guide - Downloaded Version 1.8.0 See the Directory of published versions

Use Case Vitals

Guidance and background specific to the Vitals domain.

LOINC codes

LOINC codes are assigned to Vitals per the guidance in US Core.

Units

VistA does not store units; they are inferred by client applications based on business assumptions. Units are asserted by these maps based on the type of vital sign - e.g., blood pressure is always presumed to be recorded in mmHg.

The M routine UNIT^VPRDGMV returns:

 UNIT(X) ; -- Return unit for vital type X
  N Y S Y=""
  I TYPE="BP"  S Y="mm[Hg]"
  I TYPE="T"   S Y="F"
  I TYPE="R"   S Y="/min"
  I TYPE="P"   S Y="/min"
  I TYPE="HT"  S Y="in"
  I TYPE="WT"  S Y="lb"
  I TYPE="CVP" S Y="cmH2O"
  I TYPE="CG"  S Y="in"
  I TYPE="PO2" S Y="%"
  Q Y

We follow similar logic, with the caveat that US Core specifies [degF] (or Cel) for temperature, [in_i] (or cm) for height or circumference, and [lb_av] (or kg) for weight.

Qualifiers

VistA vital sign records have a single qualifier property. The meanings of these qualifiers, however, differ, and they belong in different FHIR data elements. The terminology maps for the qualifier field assigns the VistA values to the appropriate slots, as illustrated here.