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Public Health — Seattle & King County monitors drug overdose data to detect potential overdose clusters and identify emerging trends. Since most overdoses that occur are non-fatal, it is important to monitor trends of non-fatal overdose, as well as fatal overdose. On this page, you will find up-to-date information about overdoses treated by King County Emergency Medical Service (EMS) agencies and King County Emergency Departments (ED).




Description of data sources


Emergency Medical Services

When Emergency Medical Technicians (EMTs) and Paramedics respond to 911 calls, they enter information about the incident in an electronic health record. All Emergency Medical Service agencies operating in King county use the same centralized electronic health record system that feeds into the National Emergency Medical Services Information System (NEMSIS), which is a national database that stores EMS data. After de-duplicating NEMSIS data, we created an overdose likelihood score, which is a sum of the number of factors that were documented in the health record generated for a particular patient receiving EMS services in King County:  

  • Primary & Secondary Impressions
  • Opioid* mentioned in chief complaint and/or narrative
  • Overdose* mentioned in chief complaint and/or narrative
  • Respiratory Rate <11 OR decreased respirations* mentioned in chief complaint and/or narrative
  • Glasgow Coma Scale <15 OR decreased level of consciousness* mentioned in chief complaint and/or narrative
  • Naloxone listed as an EMS-administered medication OR naloxone administration* mentioned in chief complaint and/or narrative
  • Pinpoint pupils* mentioned in narrative or chief complaint
  • Drug paraphernalia present

[*A number of terms indicative of this phrase were included in query]

We defined probable overdose as:

  • > 4 of the 8 criteria were met, including at least two of the following: primary or secondary impression indicative of overdose, free text terms indicative of overdose, or naloxone administration.

Incidents involving alcohol and other acute health issues (e.g., hypoglycemia, seizure) that were erroneously captured by this query were re-classified as non-drug overdose.


Emergency Department

The Washington State Department of Health manages syndromic surveillance data through the Rapid Health Information NetwOrk (RHINO). Syndromic surveillance data is collected in near real-time from hospitals (including Emergency Departments) and clinics from across the state. Key data elements reported include patient demographic information, chief complaint, and coded diagnoses. This data is also reported to the CDC’s National Syndromic Surveillance Program (NSSP). In King County, 18 of 20 Emergency Departments participate in this syndromic surveillance system. The two non-particpating hospitals, at this time, are Virginia Mason Medical Center and Seattle Children's Hospital. In the period shown in this dashboard, Multicare-Auburn had incomplete data, since they had only joined the surveillance program in Feb 2019.

We applied a definition developed by CDC ("CDC opioid Overdose v2 CCDD Category") to identify probable opioid overdoses treated by King County EDs participating in the syndromic surviellance system. This definition is based upon chief complaint data and International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnostic codes. ED visits with ICD-10-CM diagnosis codes T40.0–T40.4, T40.6, T40.69, F11.12, F11.22, or F11.92; or chief complaint text indicating opioid use (e.g., "heroin" or "opioid") and a word or abbreviation indicating an overdose (e.g., "OD") were classified as probable opioid overdoses. The hospital region was defined as follows:

  • Central Seattle: Harborview Medical Center, Swedish-Cherry Hill, Swedish-First Hill
  • North Seattle: Northwest Hospital, Swedish-Ballard, UW Medical Center
  • East King County: Evergreen Health Kirkland, Evergreen Health Redmond, Overlake Hospital, Snoqualmie Valley Hospital, Swedish-Issaquah
  • South King County: Highline Medical Center, St. Elizabeth Hospital, St. Francis Hospital, Multicare Medical Centers at Auburn and Covingtron, Valley Medical Center