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15-Mar-2013
Version 2 - Data Dictionary FAQ

Welcome the FAQs section of the NEMSIS website. As the center receives questions from both EMS agencies and software developers, we will try to update this section. If you have any questions, please feel free to contact the NEMSIS Technical Assistance Center. We will try to update this section as often as possible.

Questions

Data Dictionary

  • Medication Administered Route (E18_04): What would be the route of administration for bag valve mask (BVM), non-rebreather mask, small volume nebulizer, or aerosol?

  • Can you tell me what "Relevant Value for Data Element & Patient Care” means?
  • The ICD-9-CM Procedure Codes in the NEMSIS Data Dictionary match conventional ICD-9-CM Procedure Codes For example, you have a code 96.051.  There is no such code in ICD-9-CM. Where did NEMSIS get their list?.
  • Some people wonder if there is a way to add multiple leads when you do an EKG. Right now we have to pick a single lead (ie lead: II) if would be nice if we could pick multiple leads (ie..leads II, III, and AVF) when we post an EKG to the system, instead of posting it 3 different times.
  • Some people have difficulty reconciling “Cause of Injury” (E10_01) and “Mechanism of Injury” (E10_03). Cause of Injury is defined as “The category of the reported/suspected external cause of the injury.”  Mechanism of Injury is defined as “The mechanism of the event which caused the injury.” Most EMS Run Sheets don’t include the Cause of Injury, just the Mechanism of Injury.  Perhaps the lack of both or one or the other is due to a misconception that each one means the same. 
  • Among the NEMSIS National Elements and in the “Additional Information” section for E09_04, E09_11, E09_12, and E09_13, a reference is made to “Reason for Encounter”.  I can’t seem to find a NEMSIS data element entitled “Reason for Encounter”.  Do you have any recommendations?
  • Question:  Is there a separate CPT coding system for pre-hospital, and if so, do you know how I can get a copy?

Question: About date and time

Q: How do I express times to the NEMSIS 2.2.1 standard?

A: Times are expressed in UTC (Coordinated Universal Time), with a special UTC designator ("Z").
Times are expressed in local time, together with a time zone offset in hours and minutes. –A time zone offset of "+hh:mm" indicates that the date/time uses a local time zone which is "hh" hours and "mm" minutes ahead of UTC. –A time zone offset of "-hh:mm" indicates that the date/time uses a local time zone which is "hh" hours and "mm" minutes behind UTC.

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Question: About variables with lists (e.g., Procedures)

Q: EMS Procedures (E19_03) is an example of a variable with an incomplete list. We have tried to collapse all documented procedures into the list...but some just do not fit?

A: Several variables contained in the NHTSA 2.2.1 Data Dictionary contain lists considered incomplete. This is an area of concern that will be addressed during the next revision of the data dictionary. Until that time, it is suggested that states and agencies retain their larger lists. When data is exported to the National EMS Database, state-specific values that map to the current lists should be collapsed and others that do not map should be coded as -5.

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Question: About difference between Gold and Silver compliance

Q: What is the difference between Gold and Silver level compliance? Is Silver compliance just the elements marked as "National" in the Data Dictionary?

A: Several Gold level compliance indicates the ability to generate any of the 400+ data elements listed in the NHTSA 2.2.1 standard. A Gold level compliant product would be able to be marketed to any U.S. state or territory. Silver level compliance is not just the data elements marked as "National" in the NEMSIS Data Dictionary. Silver level is meant to allow a product to receive certification based just on elements requested by specific states or territories. These must include the 68 required "National" elements, but would typically include many more based on state/territory requirements.

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Question: Why does NHTSA 2.2.1 and NTDS share common XSDs

Q: I have heard that the NHTSA 2.2.1 database shares common XSDs with the National Trauma Data Standard (NTDS). Why is this?

A: The National Trauma Data Standard (NTDS) data dictionary contains a number of variables that are to be obtained from the pre-hospital record. The programming language that defines variables in NTDS and NHTSA 2.1.1 were designed to exactly match. This was done so that "next generation" trauma registry software and pre-hospital software could exchange data. Thus, in the future, trauma registrars may open a new record on a patient, only to find that all of the pre-hospital variables have "auto-populated" the record. Similarly, when an abstractor finishes a trauma registry record, ED and hospital outcome data could "back-populate" the EMS record, allowing EMS to evaluate QA topics for transported patients. For a detailed description of the overlap between the two data bases, click on this link. In the linked document, green variables demonstrate direct XML and XSD compatability when moving from NEMSIS to NTDS.  Yellow indicates variables in NEMSIS that could “inform” trauma registry abstractors, but no direct data transfer is possible (i.e., there is non-matching XML and XSDs)

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Question: How do I code an injury caused by a large animal?

Q: Cause of Injury (E10_01): How do I code an injury due to a large animal?

A: This is a known problem with E10_01. For now, we are instructing folks to code large animal injuries primarily due to a fall (e.g., fall from a horse) as 9550, kicked by a large animal (e.g., kicked by a horse) as 9640 and biten by a large animal (e.g., bite from a horse) as 9510.

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Question: Where can I find the definitions for CMS Service levels?

Q: CMS Service Level (E07_35): Where can I find the definitions for different service levels?

A: The definitions for CMS Service Levels may be found in the following CMS document. Please click on this link.

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Question: What is the route of adminisration for common oxygen and aerosol delivery devices?

Q: Medication Administered Route (E18_04): What would be the route of administration for bag valve mask (BVM), non-rebreather mask, small volume nebulizer, or aerosol?

A: The medication route (E18_04) for these medical devices is: Inhalation (4185).

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Question: Can you tell me what "Relevant Value for Data Element & Patient Care” means?

Q: Can you tell me what "Relevant Value for Data Element & Patient Care” means when associated with the "Field Values" section of the NEMSIS Data Dictionary?

A: Variables with a finite set of response categories are defined under “Field Values” (for example, Race).  Variables that have an infinite response set…such as times and dates list the term: “Relevant Value for Data Elements and Patient Care” under Field Values.  This statement basically indicates that the respondent should report the appropriate value for that variable and that NEMSIS has not (or cannot) predefine the correct response category.

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Question: About procedure codes.

Q: The ICD-9-CM Procedure Codes in the NEMSIS Data Dictionary match conventional ICD-9-CM Procedure Codes For example, you have a code 96.051.  There is no such code in ICD-9-CM. Where did NEMSIS get their list?

A: Traditional ICD-9-CM Codes were expanded to allow for a distinction among similar procedures which have the same ICD-9-CM code. As an example:
96.051: defined as Other intubation of respiratory tract (adds 1 for Combitube)
96.052: defined as Other intubation of respiratory tract (adds 2 for Laryngeal Mask)

Both of these correspond to the ICD-9-CM value of 96.05, but the added value provides additional information regarding the specific procedure performed. To get the correct ICD-9-CM Code, typically the last digit (Usually the 3rd digit to the right of the decimal point) needs to be dropped.  This is the exact method we use in NEMSIS to extend codes.

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Question: How do we account for multiple leads when doing an EKG?

Q: There appears to be an issue with E21_06, EKG Lead.  The NEMSIS 2.2.1 datset has this Data entry as a Text entry and only one possible entry. I was wondering if there is a way to add multiple leads when you do an EKG. Right now we have to pick a single lead (ie lead: II) if would be nice if we could pick multiple leads (ie..leads II, III, and AVF) when we post an EKG to the system, instead of posting it 3 different times.

A: In actuality, the E21_06 element is not text but has coded values for each choice of EKG lead. But, as you say, the current NHTSA definition only allows selecting one EKG lead, not multiples.

Unfortunately, multiple EKG selection would not be possible without a change to the NEMSIS XML schema.  As you know, we have tried very hard not to make scheme changes to allow vendors to build to a static standard.  Thus, we have added this “problem” to the list of things to consider for version 3. One possibility for now would be to use the Research Field E23_09 if you want to record multiple EKG leads. E23_09 is a simple text field, so you could store whatever you want. This would require that the State data dictionary define how you would want the data to be sent, the providers to collect the data as prescribed by the Sate, and then a software vendor to provide a customized change to collect and export the data in element E23_09.

I know this is probably not the answer that you were looking for.  There are a number of these “important” changes that version 3 can address.

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Question: How so you determine the difference between "Cause of Injury" and "Mechanism of Injury"?


Q: Some peoplehave difficulty reconciling “Cause of Injury” (E10_01) and “Mechanism of Injury” (E10_03). Cause of Injury is defined as “The category of the reported/suspected external cause of the injury.”  Mechanism of Injury is defined as “The mechanism of the event which caused the injury.” Most EMS Run Sheets don’t include the Cause of Injury, just the Mechanism of Injury.  Perhaps the lack of both or one or the other is due to a misconception that each one means the same. 

A: E10_03 is just broader categorization of E10_01 and relates back to an American College Surgeons suggestion that all injuries “generally” categorized as Blunt, Burn, Penetrating.  Thus, E10_03 is a generalization of E10_01.  This is why only E10_01 is a required national element.   

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Question: About the "Reason for Encounter".

Q: Among the NEMSIS National Elements and in the “Additional Information” section for E09_04, E09_11, E09_12, and E09_13, a reference is made to “Reason for Encounter”.  I can’t seem to find a NEMSIS data element entitled “Reason for Encounter”.  Do you have any recommendations?

A: EMS personnel are not in a position to “diagnose” patients.  Yet it would be very valuable to develop a mechanism allowing EMS personnel to define the reason for a patient encounter.  Dr. Greg Mears developed an algorithm allowing EMS to provide this information.  A PowerPoint slide presentation defining this algorithm is available at: http://www.nemsis.org/referenceMaterials/presentations.html

The “reason for encounter” variable is a calculated field that would be available only after the needed fields were collected and reported to the agency, state or the National EMS Database.  At this point the algorithm would be applied to the existing data to calculate the reason for Encounter.

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Question:  Is there a separate CPT coding system for pre-hospital, and if so, do you know how I can get a copy?

Q: According to the NEMSIS data dictionary, the standard Procedure codes (D04_04) were generated using the CPT code list. In looking at a CPT coding manual, I was unable to find codes that matched those listed in the dictionary. Is there a separate CPT coding system for pre-hospital, and if so, do you know how I can get a copy?

A: There is no separate CPT code list for pre-hospital, but the NEMSIS version 2.2.1 schema (XSD) was defined with a fixed list of codes that are typically used for pre-hospital. Most likely for the version 3 data set we will allow any CPT code, but at the moment to pass XML validation the code must be from the fixed list in the XSD. And as far as I know these codes are in any CPT coding manual. Adding state-specific procedure codes beyond those in the NEMSIS XSD means that the XML data will not pass validation against our schema. If any state is requiring that then they will probably need a custom schema for the state and then map the additional procedure codes back to the NEMSIS list before they send XML data to the NEMSIS national data base.

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