The most common type of stroke in ACLS is ischemic stroke, accounting for about 87% of all strokes. Ischemic strokes occur when a blood clot blocks blood flow to the brain, cutting off oxygen to brain tissue. The remaining 13% are hemorrhagic strokes, caused by a blood vessel that ruptures and bleeds into or around the brain. Understanding this distinction is central to ACLS stroke management because the two types require opposite treatment approaches.
Why the Stroke Type Matters in ACLS
ACLS protocols treat stroke as a time-critical emergency, similar to a heart attack. The reason identifying ischemic versus hemorrhagic stroke is so important comes down to one decision: whether to give a clot-dissolving medication. Ischemic strokes are caused by a clot, so dissolving it can restore blood flow and save brain tissue. But giving that same medication to someone with a hemorrhagic stroke, where a vessel has already burst, would make the bleeding worse and could be fatal.
This is why brain imaging happens before any clot-dissolving treatment begins. A non-contrast CT scan is the most widely used tool in acute stroke because it can quickly rule out bleeding in the brain. If no hemorrhage is visible, the team proceeds with ischemic stroke protocols.
How Ischemic Strokes Happen
Ischemic strokes fall into two main categories based on where the clot forms. In a thrombotic stroke, a clot develops directly inside one of the arteries supplying the brain, usually at a site already narrowed by fatty buildup in the vessel wall. In an embolic stroke, the clot forms somewhere else in the body (often the heart) and travels through the bloodstream until it lodges in a brain artery too narrow for it to pass through. Both types produce the same result: brain tissue downstream of the blockage loses its blood supply and begins to die within minutes.
Recognizing Stroke Signs in ACLS
ACLS emphasizes rapid stroke recognition using standardized assessment tools. The Cincinnati Prehospital Stroke Scale evaluates three things: facial droop (asking the patient to smile and checking for one-sided weakness), arm drift (asking the patient to hold both arms out and watching if one drifts downward), and speech abnormalities (listening for slurred or garbled words). If any one of these is abnormal, there is a high probability the patient is having a stroke.
A more detailed version of this scale adds checks for eye movement and level of consciousness to help predict whether a large artery in the brain is blocked. That distinction matters because large vessel blockages may need a more aggressive intervention beyond clot-dissolving medication alone.
Time Targets for Treatment
ACLS frames stroke care around strict time benchmarks because every minute of blocked blood flow destroys more brain tissue. The American Heart Association’s target goals lay out the following sequence once a patient arrives at the hospital:
- CT scan started: within 15 to 25 minutes of arrival
- CT scan interpreted: within 25 to 45 minutes of arrival
- Clot-dissolving medication given (if eligible): within 30 to 60 minutes of arrival
The fastest benchmark, known as a 30-minute door-to-needle goal, calls for the CT to begin within 15 minutes and the medication to be administered within 30 minutes. Not every hospital can consistently hit that target, so tiered goals at 45 and 60 minutes also exist. Regardless of the tier, the principle is the same: shorter times lead to better outcomes.
Clot-Dissolving Treatment
For eligible ischemic stroke patients, intravenous clot-dissolving medication can be given within 4.5 hours of symptom onset. The 2026 AHA guidelines now endorse two options for this: alteplase (the traditional choice) and tenecteplase, which has shown equivalent effectiveness with some practical advantages, including a simpler dosing method.
For select patients who wake up with stroke symptoms or arrive between 4.5 and 9 hours after onset, advanced brain imaging can determine whether there is still salvageable tissue. If imaging shows a mismatch between tissue that has already died and tissue that is at risk but still alive, clot-dissolving treatment may still be an option even outside the standard window.
Mechanical Clot Removal
When imaging reveals that a large artery in the brain is blocked, a procedure called mechanical thrombectomy may be performed. A catheter is threaded through the blood vessels to physically pull the clot out. This is supported within the first 6 to 8 hours after symptom onset for most patients, and clinical trials have shown it can be safe and effective up to 16 or even 24 hours in carefully selected patients whose imaging shows enough brain tissue still worth saving.
This procedure is performed at specialized stroke centers, not at every hospital. ACLS protocols account for this by emphasizing early identification of patients who may need transfer to a facility with thrombectomy capability.
Hemorrhagic Stroke in ACLS
Although hemorrhagic strokes make up only 13% of cases, they tend to be more immediately dangerous. When a blood vessel ruptures in the brain, the bleeding creates pressure that damages surrounding tissue. Clot-dissolving medications are strictly off-limits. Instead, treatment focuses on controlling blood pressure, reversing any blood-thinning medications the patient may be taking, and in some cases, surgical intervention to relieve pressure.
This is precisely why the CT scan is the first critical step in ACLS stroke care. The entire treatment pathway hinges on whether the stroke is ischemic or hemorrhagic, and that answer can only come from imaging. No physical exam or stroke scale can reliably distinguish between the two types on its own.