The acls stroke algorithm is one of the most high-stakes protocols you will encounter during ACLS certification, and mastering it can mean the difference between a patient walking out of the hospital and suffering permanent disability. Stroke is the fifth-leading cause of death in the United States and a leading cause of long-term disability, which is why the American Heart Association dedicates a full algorithm to its acute management. Understanding the time-sensitive decision trees, neurological assessment tools, and pharmacological criteria embedded in this algorithm is essential for every ACLS candidate.
The acls stroke algorithm is one of the most high-stakes protocols you will encounter during ACLS certification, and mastering it can mean the difference between a patient walking out of the hospital and suffering permanent disability. Stroke is the fifth-leading cause of death in the United States and a leading cause of long-term disability, which is why the American Heart Association dedicates a full algorithm to its acute management. Understanding the time-sensitive decision trees, neurological assessment tools, and pharmacological criteria embedded in this algorithm is essential for every ACLS candidate.
At its core, the stroke algorithm is built around one uncompromising principle: time is brain. Every minute that a large-vessel ischemic stroke goes untreated, approximately 1.9 million neurons are destroyed. That biological reality drives every element of the algorithm, from the initial emergency dispatch through hospital arrival and the final decision about thrombolytic therapy or mechanical thrombectomy. On your ACLS exam, questions will test whether you know not just what to do, but in what order and within what time constraints.
The algorithm begins in the field with emergency medical services activating the stroke chain of survival. Dispatchers are trained to ask about sudden facial drooping, arm weakness, and speech difficulty — the hallmarks of the Cincinnati Prehospital Stroke Scale. When EMS providers identify a likely stroke, they pre-notify the receiving hospital so that the stroke team can mobilize before the patient arrives. This pre-notification step consistently reduces door-to-CT times and is a key element tested on the ACLS exam.
Upon hospital arrival, the algorithm moves rapidly through a structured sequence: immediate general assessment within ten minutes of arrival, neurological evaluation and CT imaging within twenty-five minutes, CT interpretation within forty-five minutes, and fibrinolytic therapy (if eligible) within sixty minutes. These benchmark times are not suggestions — they are evidence-based targets that the Joint Commission uses to certify Comprehensive Stroke Centers, and the ACLS exam expects you to know them cold.
Patient eligibility for intravenous alteplase (tPA) is one of the most detail-heavy sections of the stroke algorithm, and it generates a disproportionate share of exam questions. Providers must weigh an extensive list of inclusion and exclusion criteria in a compressed time window. Age, blood pressure, blood glucose, onset time, recent surgery, anticoagulant use, and neurological severity all factor into the decision. A thorough grasp of these criteria is non-negotiable for passing the certification exam and for safe clinical practice.
Beyond tPA, the algorithm also addresses large-vessel occlusion and the growing role of endovascular therapy. Mechanical thrombectomy has dramatically expanded the treatment window for select patients, with evidence supporting intervention out to 24 hours in certain imaging-selected cases. ACLS candidates who understand both the medical and interventional pathways will be better prepared for both exam questions and real-world resuscitation scenarios involving stroke patients.
This complete study guide breaks down every phase of the ACLS stroke algorithm — from prehospital recognition through in-hospital management — using the clear, systematic structure that ACLS certification examiners expect. Whether you are preparing for your initial certification or a recertification renewal, this guide gives you the conceptual framework and factual detail you need to perform with confidence.
EMS uses the Cincinnati Prehospital Stroke Scale to identify facial droop, arm drift, and abnormal speech. Positive screen triggers immediate hospital pre-notification and rapid transport. EMS documents last-known-well time — the critical clock-start for all subsequent treatment windows.
Stroke team activation upon arrival. Triage nurse performs general assessment, obtains IV access, draws labs (CBC, BMP, coagulation studies, glucose), and attaches cardiac monitor. NIHSS baseline assessment begins. Target: stroke team at bedside within 10 minutes of door arrival.
Non-contrast CT head is the priority study to rule out hemorrhagic stroke before any thrombolytic therapy. CT must be completed within 25 minutes of arrival. CT perfusion or CT angiography may follow if large-vessel occlusion is suspected. Radiology reads the scan within 45 minutes.
Physician reviews full inclusion/exclusion criteria for IV alteplase while awaiting CT results. Blood pressure must be below 185/110 mmHg before administration. Blood glucose must be between 50–400 mg/dL. Informed consent is obtained and family notified of risks and benefits.
Door-to-needle time target is 60 minutes or less — a Joint Commission benchmark for certified stroke centers. Alteplase dose is 0.9 mg/kg (max 90 mg): 10% given as IV bolus over 1 minute, remaining 90% infused over 60 minutes. No anticoagulants or antiplatelets for 24 hours post-tPA.
Patient transferred to stroke unit or ICU for 24-hour neurological monitoring. Repeat CT at 24 hours before starting antithrombotic therapy. If large-vessel occlusion persists despite tPA or patient is not a tPA candidate, neurointerventional team evaluates for mechanical thrombectomy up to 24 hours.
Neurological assessment is the diagnostic backbone of the ACLS stroke algorithm, and two scales dominate both clinical practice and certification exam questions: the Cincinnati Prehospital Stroke Scale (CPSS) and the National Institutes of Health Stroke Scale (NIHSS). Understanding what each scale measures, how it is scored, and how scores inform treatment decisions is critical for any ACLS candidate. The CPSS is designed for rapid field use by EMS providers and takes under sixty seconds to complete.
The Cincinnati Prehospital Stroke Scale assesses three findings: facial droop, arm drift, and abnormal speech. Facial droop is tested by asking the patient to show their teeth or smile — asymmetry indicates a positive finding. Arm drift is evaluated by having the patient close their eyes and hold both arms outstretched for ten seconds; one arm that drifts downward or pronates suggests contralateral motor cortex involvement. Speech is assessed by asking the patient to repeat a simple sentence, listening for slurring, word-finding difficulty, or complete absence of speech.
A single abnormal finding on the CPSS carries a sensitivity of approximately 59% for stroke, but when all three findings are abnormal, sensitivity approaches 88%. ACLS exams often present scenarios where you must identify whether a patient's presentation constitutes a positive CPSS screen. Remember that the CPSS can be positive in conditions that mimic stroke, including severe hypoglycemia, Todd's paralysis after a seizure, and certain metabolic encephalopathies — always check blood glucose early in the assessment.
The NIHSS is used in the emergency department to quantify neurological deficits and stratify stroke severity. It evaluates eleven domains including level of consciousness, gaze, visual fields, facial palsy, motor arm and leg, limb ataxia, sensory function, language, dysarthria, and extinction or inattention. Each domain is scored on an ordinal scale, and individual scores are summed for a total between 0 and 42. A score of 0 indicates no stroke symptoms; a score above 25 indicates very severe stroke.
NIHSS scores directly inform treatment decisions within the algorithm. Patients with an NIHSS of 0–5 may represent minor strokes or TIAs, and the benefit-risk ratio for tPA is carefully weighed. Patients with scores above 22 carry higher risk of hemorrhagic transformation after tPA, which must be factored into the eligibility decision. ACLS exam questions may describe a patient's neurological findings without providing a numeric score, requiring you to estimate severity and match it to the appropriate algorithm pathway.
The Los Angeles Prehospital Stroke Screen (LAPSS) and the FAST-ED scale are additional assessment tools that appear in some ACLS study materials, though the CPSS remains the most commonly tested prehospital tool on certification exams. FAST-ED adds distal vessel occlusion markers — eye deviation and denial or neglect — to the classic FAST acronym, helping EMS identify large-vessel occlusions that are more likely to benefit from mechanical thrombectomy at a thrombectomy-capable center.
Blood glucose measurement is an often-overlooked but mandatory step in the stroke algorithm. Hypoglycemia (glucose below 50 mg/dL) can produce focal neurological deficits indistinguishable from ischemic stroke, and treating a hypoglycemic patient with tPA carries catastrophic risk. Conversely, hyperglycemia above 400 mg/dL is an exclusion criterion for tPA. Providers must obtain a point-of-care glucose result before the CT scanner and certainly before any fibrinolytic decision. ACLS exam scenarios that omit glucose testing are testing whether you identify it as a missing step.
For a patient to receive IV alteplase, the diagnosis must be ischemic stroke with a measurable neurological deficit, onset of symptoms must be clearly established within 3 hours (or up to 4.5 hours for the extended window), age must be 18 or older, CT imaging must show no hemorrhage or established large infarct core, blood pressure must be below 185/110 mmHg at time of infusion, and blood glucose must fall between 50 and 400 mg/dL. Each of these criteria must be met simultaneously — a single missing element eliminates eligibility.
The 4.5-hour extended window introduced by the ECASS III trial applies to most patients but carries additional exclusion criteria: patients over age 80, those with both prior stroke and diabetes, NIHSS above 25, anticoagulant use regardless of INR, and imaging showing greater than one-third MCA territory involvement are excluded from the extended window. On the ACLS exam, questions about the extended window typically test whether candidates know these extra restrictions, not just the 4.5-hour time limit itself.
Absolute contraindications to tPA must be memorized because their presence makes alteplase administration unacceptable regardless of stroke severity. These include: hemorrhage on CT (intracranial or subarachnoid), significant head trauma or prior stroke within 3 months, intracranial or intraspinal surgery within 3 months, history of prior intracranial hemorrhage, uncontrolled hypertension above 185/110 despite treatment, active bleeding or acute trauma, bacterial endocarditis, aortic arch dissection, and blood glucose below 50 or above 400 mg/dL. ACLS exam scenarios often embed one of these contraindications in a detailed patient history.
Recent major surgery is a relative contraindication that frequently appears in exam scenarios. Surgery within 14 days at a site that could cause life-threatening bleeding is generally considered an absolute contraindication, while surgery at a non-critical site within 14 days may be weighed against stroke severity. Providers must think carefully about whether surgical sites — such as a recent coronary artery bypass, bowel resection, or orthopedic procedure — represent life-threatening bleeding risk. ACLS candidates should default to recognizing recent major surgery as a contraindication flag that demands attending physician review.
Relative exclusions require individualized risk-benefit analysis rather than automatic disqualification. These include: minor or rapidly improving symptoms, seizure at stroke onset with postictal deficits, major trauma within 14 days (non-life-threatening site), recent arterial puncture at a non-compressible site, recent lumbar puncture, platelet count below 100,000, heparin use within 48 hours with elevated PTT, INR above 1.7, and current anticoagulant use. The decision to treat despite a relative exclusion typically requires an attending or stroke neurologist to document the rationale explicitly.
Pregnancy presents a special consideration: tPA is not absolutely contraindicated, but the potential for placental abruption and fetal harm means it is reserved for severe, life-threatening strokes where the maternal benefit clearly outweighs fetal risk. Wake-up strokes — where the patient awakens with deficits and the last-known-well time is before sleep — traditionally fell outside the treatment window, but DWI-FLAIR mismatch imaging now allows selected wake-up stroke patients to receive tPA. ACLS candidates should know that imaging selection can sometimes substitute for a clear symptom onset time.
ACLS examiners consistently test whether candidates understand that the stroke treatment window starts from the last time the patient was known to be neurologically normal — not from when symptoms were discovered. A patient who goes to bed well at 10 PM and awakens with deficits at 6 AM has an 8-hour window by discovery time, but the actual last-known-well time is 10 PM. Always anchor your treatment eligibility calculation to last-known-well, not symptom discovery.
In-hospital management of ischemic stroke follows the ACLS algorithm's structured sequence with precision, and understanding each phase in detail prepares you both for high-stakes exam scenarios and for real-world resuscitation team leadership. After the patient clears CT imaging without hemorrhage, the team moves simultaneously on multiple tracks: completing the eligibility assessment, obtaining informed consent, managing blood pressure, and preparing the alteplase infusion. This parallel processing is what allows certified stroke centers to meet the 60-minute door-to-needle benchmark.
Blood pressure management before and after tPA is one of the most nuanced pharmacological elements of the stroke algorithm. Before alteplase administration, the target is below 185/110 mmHg. If blood pressure is above this threshold, providers use labetalol (10–20 mg IV push, may repeat once) or nicardipine (5 mg/hr IV titrated up to 15 mg/hr) to achieve target. If blood pressure cannot be safely controlled to below 185/110, the patient is not a tPA candidate. After administration, the target tightens to below 180/105 mmHg for the next 24 hours.
During the alteplase infusion and for 24 hours afterward, the clinical team monitors neurological status using serial NIHSS assessments every 15–30 minutes during infusion and every hour for the first 6 hours. Any sudden neurological deterioration — new severe headache, acute hypertension, nausea, vomiting, or a drop in NIHSS score — triggers immediate suspension of the infusion and emergency CT to evaluate for symptomatic intracranial hemorrhage. Symptomatic hemorrhage management includes cryoprecipitate (to replace fibrinogen depleted by alteplase) and urgent neurosurgical consultation.
Large-vessel occlusion (LVO) represents the most severe form of ischemic stroke and requires consideration for mechanical thrombectomy in addition to or instead of tPA. LVO is suggested by an NIHSS score above 6, gaze deviation, and dense MCA sign on CT. CT angiography or MR angiography confirms the presence and location of the thrombus. The HERMES collaboration meta-analysis demonstrated that thrombectomy reduces the rate of disability across all LVO stroke subtypes, with an absolute risk reduction in moderate-to-severe disability of approximately 20%.
The thrombectomy treatment window has dramatically expanded over the past decade. The DAWN and DEFUSE 3 trials demonstrated benefit for selected patients treated up to 16–24 hours after last-known-well time, provided that imaging shows a small infarct core relative to a large penumbra. This mismatch criterion — assessed by CT perfusion or diffusion-weighted MRI — identifies tissue that is ischemic but still viable, making it a target for revascularization. ACLS candidates should know that the extended thrombectomy window applies only to LVO, not to all ischemic strokes, and requires imaging-based patient selection.
Post-stroke care in the stroke unit or ICU focuses on preventing secondary neurological injury. Temperature management targets normothermia, as hyperthermia above 37.5°C worsens neurological outcomes by increasing metabolic demand in ischemic tissue. Hyperglycemia is aggressively managed — blood glucose above 180 mg/dL in the post-stroke period is associated with worse outcomes and hemorrhagic transformation risk. Swallowing evaluation before any oral intake is mandatory, as aspiration pneumonia is the most common post-stroke medical complication and a major driver of in-hospital mortality.
Cardiac monitoring for 24–48 hours post-stroke is recommended because atrial fibrillation is found in approximately 25% of cryptogenic stroke patients via prolonged monitoring. Identifying new-onset AF changes the secondary prevention strategy from antiplatelet therapy to anticoagulation. The ACLS algorithm connects the acute management of stroke with the longer arc of secondary prevention, and exam questions may test whether candidates recognize the downstream implications of rhythm findings made during the acute hospitalization phase.
Preparing for ACLS stroke algorithm questions on your certification exam requires a different study strategy than preparing for cardiac arrest or arrhythmia content. Stroke algorithm questions are heavily scenario-based and often embed a single disqualifying detail — a recent surgery, a blood pressure of 190/115, a glucose of 45, or a symptom onset 5.5 hours ago — that changes the correct answer entirely. Reading questions carefully and systematically working through eligibility criteria is more important than pattern-matching to a familiar scenario type.
The most productive study approach is to practice the eligibility decision tree repeatedly with varied patient scenarios. Build a mental checklist: Is CT clear of hemorrhage? Is the time window met? Is blood pressure controlled? Is glucose in range? Are there any absolute contraindications in the history? Only after working through all five gates should you arrive at a treatment decision. This systematic approach mirrors what examiners are testing and prevents the common error of focusing on one criterion while overlooking another.
Pharmacology questions tied to the stroke algorithm most commonly target alteplase dosing and blood pressure medications. Know the alteplase dose of 0.9 mg/kg with a maximum of 90 mg, with 10% as the initial bolus and 90% infused over 60 minutes. Know labetalol (10–20 mg IV, may repeat once) and nicardipine (start 5 mg/hr, titrate) as the first-line blood pressure agents before tPA. Know that nitroprusside is generally avoided in acute stroke because of its cerebral vasodilatory effects and risk of increasing intracranial pressure.
ACLS exam scenarios about stroke occasionally test knowledge of hemorrhagic stroke management, which follows a completely different algorithm. Intracerebral hemorrhage (ICH) management focuses on blood pressure control (target below 140 mmHg systolic for most patients), reversal of anticoagulation, and neurosurgical evaluation. Subarachnoid hemorrhage (SAH) requires nimodipine to reduce vasospasm and urgent neurosurgical evaluation. The ACLS algorithm explicitly uses CT imaging to distinguish ischemic from hemorrhagic stroke before any treatment, precisely because the management pathways diverge so dramatically.
Transient ischemic attacks (TIAs) deserve specific attention in exam preparation because they present with classic stroke symptoms that resolve within 24 hours (by the old definition) or within 1 hour with no diffusion-weighted MRI changes (by the current definition). TIA patients are at high short-term risk for completed stroke — the ABCD2 score estimates 2-day stroke risk based on age, blood pressure, clinical features, duration, and diabetes. ACLS scenarios may present a patient whose symptoms have resolved and ask whether treatment is still warranted. The answer is aggressive workup and risk stratification, not reassurance and discharge.
High-yield exam topics that candidates frequently underestimate include: the mandatory 24-hour CT before starting anticoagulation post-tPA, the distinction between the 3-hour and 4.5-hour windows and their respective exclusions, the requirement that blood pressure remain below 180/105 for 24 hours after tPA rather than the pre-treatment threshold of 185/110, and the role of imaging selection criteria for extended-window thrombectomy. These details appear regularly in challenging exam questions and are often the difference between passing and failing scores on the stroke section.
Using practice questions strategically accelerates retention of stroke algorithm details far more effectively than passive review. After each incorrect answer, trace your reasoning back to the decision point where you diverged from the algorithm, and identify which criterion or time benchmark you overlooked. Most stroke algorithm errors on ACLS exams fall into predictable patterns: missing a contraindication embedded in the history, confusing the pre- and post-tPA blood pressure targets, or misidentifying the treatment window boundaries. Targeted drilling on these failure modes builds the procedural fluency that certification exams reward.
Practical preparation for the ACLS stroke algorithm section goes beyond memorizing criteria — it requires building clinical reasoning habits that hold up under the time pressure of a certification exam. One of the most effective study techniques is to practice reading patient scenarios and immediately identifying the category of decision being tested: Is this a time window question? A contraindication identification question? A dosing question? A post-tPA monitoring question? Categorizing the question type before reading the answer choices focuses your reasoning and reduces the influence of distractors.
Another powerful preparation technique is the reverse scenario method: start with a correct treatment decision and construct a patient scenario that supports it, then change one variable at a time until the decision flips. For example, start with a patient who is a clear tPA candidate — ischemic stroke confirmed by CT, symptoms for 2.5 hours, blood pressure 170/90, glucose 110, no contraindications.
Now change the symptom duration to 5 hours. Now add a history of prior stroke 6 weeks ago. Now raise the blood pressure to 200/120. Each change tests a specific exclusion criterion and reinforces why it matters clinically.
Group study and verbal teaching are underutilized tools in ACLS preparation. Teaching the stroke algorithm to a study partner — walking through each step, fielding questions, and correcting misunderstandings — produces deeper encoding than solo review. The AHA's ACLS provider manual uses a team-based simulation model precisely because verbalizing the algorithm under mild social pressure mimics the cognitive demands of the actual certification skills station. If you can explain why a blood glucose of 45 mg/dL stops the algorithm in its tracks, you have internalized the concept rather than just memorized the fact.
Time management during the ACLS exam deserves attention. The written examination typically allocates approximately one minute per question. Stroke algorithm questions often present lengthy clinical scenarios with multiple patient details, and candidates who read every line without a systematic approach can spend three or four minutes on a single question. Practice skimming for the key algorithmic variables — onset time, blood pressure, glucose, CT findings, relevant history — and ignore narrative details that do not affect the treatment decision. Efficiency under exam conditions is a trainable skill.
The transition from ACLS knowledge to clinical application is the ultimate goal of certification. Hospitals that achieve the best stroke outcomes consistently cite standardized protocols, pre-notification communication between EMS and the stroke team, co-location of CT scanners near the emergency department, and a culture of urgent parallel processing rather than sequential steps. Understanding these systems-level factors helps ACLS providers see their role not just as individual decision-makers but as members of a coordinated team where every minute saved reflects a protocol discipline learned during certification training.
ACLS renewal candidates sometimes assume that stroke content will be familiar from their initial certification and underprepare. In practice, the AHA updates the stroke algorithm with each guideline cycle, and recertification exams reflect current evidence. The 2020 AHA guidelines introduced refined LVO identification criteria, updated the extended thrombectomy window to 24 hours for selected patients, and emphasized imaging-based selection for borderline cases. Renewal candidates should review the current algorithm as if for the first time rather than relying on what they learned in a prior certification cycle.
Finally, integrate your stroke algorithm study with the cardiac monitoring content that surrounds it in the ACLS curriculum. Post-stroke cardiac monitoring, the connection between atrial fibrillation and cardioembolic stroke, and the role of the 12-lead ECG in identifying STEMI mimics that present as stroke are all areas where the stroke and cardiac algorithms overlap. Candidates who study these intersections perform better on the exam's integrative scenario questions, which require synthesizing knowledge across multiple ACLS algorithm domains rather than applying a single protocol in isolation.