Table 2 Diverse agents of the ED

Substance use specialist services

Addiction Medicine Physician

The Addiction Medicine Physician is responsible for assessing the patient concerning their unregulated substance use, including the severity of any presenting substance use disorders and stage of change, and establishing connections to treatment [97]. They also treat withdrawal, cravings, and pain with the goal of enabling the treatment of the patient’s admitting diagnosis [89, 97]. The Addiction Medicine Physician is available seven day a week, and are on-site from 8 am and 5 pm, and available by phone from 5 pm to 8 am [88].

Addiction Assessment Nurse (AAN)

Addiction Assessment Nurses (AANs) work in the ED and have expertise in care provision for people who use unregulated substances. They can assist with various aspects of care, including liaising with the Addiction Medicine Physician, obtaining information from community health providers, connecting patients to appropriate substance use related services in the community, helping to facilitate access to the in-hospital OPS, and providing mentorship and support to ED staff. They are available seven days a week from 8 am to 6 pm.

Rapid Access Addiction Clinic (RAAC)

The RAAC is an outpatient clinic that is located within the hospital that provides short-term treatment for people with substance use specific health concerns and connects people to care providers in the community for long term management [88]. The clinic facilitates connections to a variety of health and social services such as detoxification, counselling, housing, and financial aid [98]. It is open seven days a week from 9 am to 4 pm [88]. The clinic accepts referrals from the ED and inpatient units, community providers, and patient self-referrals [98, 99]. It has a mandate to see referred patients within a 24–48 h window, and walk-ins are seen on a first come, first served basis until capacity is reached for the day [99, 100].

Overdose Prevention Site (OPS)

Registered patients of the hospital, including ED patients, have access to the in-hospital OPS [88]. At the OPS, patients can use their personal supply of injection drugs and subsequently return to the ED to continue their care. The OPS is staffed by nurses who are responsible for overdose prevention and response, and harm reduction education and supply distribution, including take-home naloxone kits and safer use supplies [88]. The OPS is open from 10 am to 8 pm seven days a week [88, 95].

Non-specialist providers

Emergency Nurse

The Emergency Nurse's role is expansive. For the purpose of this paper, which pertains to care provision for people who use unregulated substances, the Emergency Nurse is responsible for ensuring that the patient’s substance use related needs are met through advocating for any necessary interventions on their behalf, providing treatments/interventions ordered, assessing effectiveness, providing patient education, and helping to coordinate all aspects of care provision related to substance use, both within the ED and through substance use specialist services that exist outside of the ED environment.

Emergency Physician

The Emergency Physician's role is expansive. For the purpose of this paper, which pertains to care provision for people who use unregulated substances, the Emergency Physician is responsible for ensuring that the patient’s admitting diagnosis is attended to, and that any needs related to substance use are also addressed, either through their own efforts or through referral to substance use specialist services, such as the Addiction Medicine Physician, the Addiction Assessment Nurse (AAN), and the Rapid Access Addiction Clinic (RAAC).