Identifying Large Vessel Occlusion Stroke in the Pre-Hospital Setting

The Basic Life Support Patient Care Standards for paramedics in Ontario recently added the Los Angeles Motor Scale (LAMS) as a secondary screen in their Acute Stroke Bypass Protocol. Paramedics are now using the LAMS as their large vessel occlusion (LVO) screen for potential Endovascular Thrombectomy (EVT) candidacy. The LAMS is being used for those with stroke symptoms within 6 hours of onset and involves assessment of the following:

  • Facial droop
  • Arm drift
  • Grip strength

 A score of > 4 is considered ‘positive’ and the patient may be eligible for EVT.

There is NO change to the Acute Stroke Protocol of Southeastern Ontario in terms of stroke bypass or redirect for the paramedics.  Patients who fit the Paramedic Prompt Card for Acute Stroke Bypass Protocol criteria will go to the closest Stroke Centre if within the 6 hour time window. If outside the 6 hour time window, they go to the local hospital ED who will assess and decide on transfer to Kingston Health Sciences Centre (KHSC)-Kingston General Hospital (KGH) for EVT. EDs across the south east are using ACT FAST as their LVO screen/triage tool and can transfer directly to KGH on Acute Stroke Protocol if ACT FAST positive in the 6 to 24 hour time window.

One question being raised from EDs in the south east is, “Why are paramedics using the LAMS and EDs using the ACT-FAST to screen for LVO?” Answer:  EDs are using the ACT-FAST because it has a higher positive predictive value for EVT (higher specificity and reliability for detecting LVO in severe stroke), but LAMS was considered easier and more feasible to implement in the pre-hospital setting and was the top choice of paramedic services.

In addition to communicating the LAMS score to the Central Ambulance Communication Centre (CACC), paramedics are also providing EDs with the “heads up” that the patient is LVO screen or LAMS positive. This valuable communication helps EDs make faster decisions about Acute Stroke Protocol including transfers for potential EVT at KHSC-KGH.

Learn more for More Info including Links to LAMS Provincial Presentation & Video and South East Poster & Pocket Guide