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Stroke Bypass

Question# 733

Question/Clarification regarding the Acute Stroke and Champlain Protocol.

According to the prompt card at the bottom of the directive in the OPCG app (where the LAMS scale is in the directive):
A patient with stroke symptoms with an onset greater than 6 hours but less than 24 hours, with a LAMS equal to or greater than 4 is supposed to be a CTAS 2 and bypassed to the civic hospital.

A patient with stroke symptoms with an onset greater than 6 hours but less than 24 hours with LAMS score LESS than 4 is also to be bypassed to the civic as well? and if that is correct, what is the expected CTAS?


Currently there is no stroke bypass for those last seen normal or who are exhibiting s/s with an onset of > 6 hours, regardless if they are LVO+ or LVO-.

There is evidence for time-sensitive benefit of TPA if provided within 4.5 hours, with some flexibility depending on imaging and neurologist, and so that is why there is bypass to stroke center up to 6 hours. There is also evidence for time-sensitive benefit for those in the 6-24 hour window are LVO+.

The province is not prepared to recommend bypass for these 6-24 hour strokes just yet however, they are slowly moving in that direction by asking paramedics to perform the LVO screen, and if positive to upgrade triage to a CTAS 2 and be sure to notify receiving hospital. That is the rationale for this change.

That said, a CVA presenting within the 6-24 hour window who is LVO+ can be a patch to consider destination change to a stroke centre, preferably one with interventional radiology that does EVT (Civic, KGH) however, other considerations will involve service and CACC agreement with the destination change based on ambulance availability/situation awareness, etc. The BHP's and the stroke neurologists at the EVT centers are okay with this practice, but they have not put it in writing yet at the provincial level.

When it comes to CTAS, the patient that is exhibiting s/s of a CVA that is > than 6 hours (non-stroke bypass) and <24 hours and LVO- is technically a CTAS 3 under the Prehospital CTAS Paramedic Guide if they ONLY have extremity weakness/symptoms of a CVA greater or equal to 3.5 hours or resolved. That said, there are several other factors to take into consideration when determining CTAS. For example, hemodynamic stability and vital signs (hypertensive), level of consciousness (altered), patient's medical history (blood thinners/bleeding disorders), or if they have any pain. These are all example of modifiers that could change the patient's CTAS to a 2 or greater which is typically the case in this population you speak of. This is why it is outlined in the prompt card that if the patient is LVO+ they automatically become a CTAS 2 (a modifier that upgrades the patient's CTAS if you will).

It is always acceptable to upgrade code and CTAS at any given time depending on patient presentation, and transport to the closest facility as these patients do not meet the Stroke Bypass Protocol. These patient's will be treated like any other CVA and still receive a head CT to rule out hemorrhage, tumor, or any alternative cause for focal deficit, receive imagine of the carotids to check for narrowing of the vessels (if so, urgent carotid endarterectomy to prevent having an even bigger stroke), potentially started on dual anti-platelets (anticoagulation if a-fib), and ideally be transferred and admitted to a stroke unit once stabilized for rehabilitation and risk factor modification.

Medical Directive Category

Stroke Bypass


05 October 2023

ALSPCS Version




Please reference the MOST RECENT ALS PCS for updates and changes to these directives.