Basic Life Support (Adult): High-Quality CPR & AED
On a ward or in the community, the first minutes after collapse are about recognition, compression quality, and early defibrillation—not prolonged assessment. This guide explains how to perform adult BLS: agonal breathing traps, compression-only vs 30:2, AED safety, team roles, and defensible arrest documentation aligned with current resuscitation guidance.
On this page
Quick facts
Key takeaway
If an adult is unresponsive with absent or abnormal breathing (including gasping), activate arrest help and start compressions immediately—limit the breathing check to 10 seconds, attach an AED as soon as it arrives, and resume CPR right after every shock or “no shock” prompt.
Procedure summary
| Field | Details |
|---|---|
| Procedure name | Basic Life Support (Adult) — CPR and AED |
| Also known as | Adult BLS; adult CPR; cardiopulmonary resuscitation; resuscitation |
| Category | Emergency resuscitation |
| Clinical purpose | Maintain circulation and oxygenation during adult cardiac arrest until advanced life support or return of spontaneous circulation. |
| Who performs | Any trained responder; registered nurses act within resuscitation training, credentialing, and local policy. |
| Typical settings | Hospital wards, emergency departments, community, long-term care, peri-arrest bays, public areas with AED access. |
| Time | Continuous until handover, ROSC, or safe termination per policy; compressor swap about every 2 minutes. |
What is adult basic life support?
Adult basic life support (BLS) is the immediate, coordinated response to a person who is unresponsive with absent or abnormal breathing—including slow, irregular, or gasping respirations that are not effective ventilation. The chain you deliver at the bedside is early recognition, high-quality chest compressions, defibrillation when indicated, and safe handover to the resuscitation team.
BLS is not the same as calling a rapid response for a deteriorating but breathing patient. When perfusion has failed, switch to arrest algorithms. If the event began with witnessed choking, complete severe FBAO management first while the patient is conscious; once unresponsive, start compressions and follow this BLS pathway.
Agonal breathing vs normal breathing
Agonal gasps are common in the first minutes of arrest and are a frequent reason compressions are delayed. They are not effective breathing.
| Observation | Likely normal / adequate | Treat as cardiac arrest |
|---|---|---|
| Pattern | Regular rate, visible chest rise, patient may cough or speak between breaths | Slow, irregular, or single gasps without sustained chest rise |
| Consciousness | Responsive or localises to voice/pain | Unresponsive to voice and central pain |
| Pulse check | May be used when trained and not delaying care in a breathing patient | Do not prolong assessment—if arrest is suspected, start compressions |
| Nurse action | ABCDE assessment, MET/RRT if deteriorating | Activate arrest response, compressions, AED |
Look, listen, and feel for breathing for no more than 10 seconds. If you are not sure breathing is normal, treat as arrest and begin compressions.
MET call vs cardiac arrest (code blue)
Ward nurses lose critical minutes when the wrong escalation is used. Use this frame before you reach the bed.
Patient still has perfusion
- Altered but present breathing; may be confused, hypotensive, or hypoxic.
- Pulse usually palpable; focus on ABCDE and reversible causes.
- Goal: prevent arrest with oxygen, fluids, glucose, and senior review.
No effective breathing
- Unresponsive with absent or abnormal breathing (including agonal gasps).
- Start compressions; assign roles; apply AED as soon as it arrives.
- Goal: CPR, defibrillation when shockable, ALS handover.
Clinical indications
- Unresponsive adult with absent or abnormal breathing after a brief check (≤10 seconds).
- Witnessed collapse with no signs of life and no effective ventilation.
- Patient becomes unresponsive during or after choking management.
- Monitored patient with asystole or ventricular fibrillation on ECG / defibrillator—compressions per ALS/BLS integration.
- Peri-arrest with sudden unresponsiveness and apnoea pending team arrival (within your training).
When to modify or stop
Valid do not attempt CPR (DNACPR) or equivalent orders mean no BLS unless local policy allows emergency exceptions—verify status when safe, without delaying care in an obvious unexpected arrest.
Do not begin compressions in an unsafe environment (electrical hazard, fire, violence). Make safe or move the patient when feasible.
Compression depth targets assume a typical adult chest. In pregnancy, trauma, or frail chest walls, follow your certified algorithm and institutional guidance for hand placement and depth.
Equipment checklist
For device-specific prompts and shock delivery, see Zoll defibrillator operation when that is your hospital equipment.
Scene preparation and team roles
- Delegate early: one person compressions, one activates emergency call and fetches AED, one prepares airway/IV access for ALS team.
- Lower the bed to a firm surface; remove excessive pillows; expose the chest for pads.
- Assign a timekeeper to announce two-minute cycles and shock readiness.
- Prepare BVM ventilation if trained to give breaths; otherwise plan continuous compressions.
Compression-only vs 30:2 ventilation
Hands-only CPR
- Use when you are not trained in rescue breaths, breaths are not feasible (PPE/infection risk), or a second rescuer is not available to ventilate without pausing compressions.
- Still apply AED as soon as possible.
When trained and able
- Deliver each breath over about one second to visible chest rise—avoid hyperventilation.
- Minimise pause before compressions resume; rotate compressor about every two minutes.
Step-by-step adult BLS
Ensure safety
Scan for hazards before approaching so you can sustain care without interruption.
Check responsiveness
Shout and tap shoulders. No response supports moving to the arrest pathway.
Activate help and request AED
Trigger your local cardiac arrest / code response and send someone for the defibrillator.
Open airway and check breathing (≤10 s)
Use head-tilt chin-lift (jaw thrust if trained for suspected trauma). Gasping = abnormal.
Start chest compressions
Centre of chest, lower half of sternum. Rate 100–120/min, depth 5–6 cm, full recoil, minimal leaning.
Ventilate if trained (30:2)
If not feasible, continue compression-only CPR. Pair with OPA and BVM only within competence.
Rotate compressor about every 2 minutes
Swap with minimal pause; pre-charge defibrillator during swaps when ALS team directs.
Apply AED pads
Expose dry chest; remove patches where pads sit; continue compressions during pad placement when possible.
Stand clear for analysis and shock
No one touches the patient. Move supplemental oxygen at least 1 metre from the chest during shock unless the patient is intubated (reduces ignition risk near the face).
Resume CPR immediately
Restart compressions straight after shock or “no shock advised” for about two minutes or until prompted.
Continue until ALS handover or ROSC
Reassess only per algorithm—avoid prolonged pulse checks that pause compressions.
Structured handover
Report times, shocks, airway actions, and suspected cause (e.g. acute coronary syndrome, stroke, hypoxia).
CPR quality checklist
| Element | Target | Bedside tip |
|---|---|---|
| Rate | 100–120/min | Count aloud; use device metronome if available |
| Depth | 5–6 cm | Allow full recoil; avoid leaning on chest |
| Fraction | Minimise pauses | Pre-plan AED placement and role swaps |
| Ventilation | Visible chest rise only | Hyperventilation reduces coronary perfusion |
| Monitoring | SpO₂ trend after ROSC | During CPR, capnography (if available) reflects ventilation quality |
Reversible causes nurses can flag early
ALS teams treat causes; nurses accelerate recognition. Use the 4 Hs and 4 Ts as a handover memory aid—treat only within scope and orders.
| Hs | Ts | Nurse bedside examples |
|---|---|---|
| Hypoxia, Hypovolaemia, Hypo/Hyperkalaemia, Hypothermia | Tension pneumothorax, Tamponade, Toxins, Thrombosis (coronary/pulmonary) | Check airway patency, empty IV bags, potassium results, temperature; consider needle decompression only if trained; mention new drugs or chest trauma history. |
After ROSC or termination
- Apply ABCDE; support airway and oxygenation; monitor with vital signs and ECG.
- Target normoxia per local targets—avoid hyperoxia when protocols specify.
- Reassess consciousness with level of consciousness tools.
- Prepare ICU/HDU transfer documentation and family communication per policy.
Nursing documentation
- Time found unresponsive; time compressions started; time AED attached; number of shocks; rhythm messages if known.
- CPR ratio used (compression-only vs 30:2); names/roles of responders.
- Airway adjuncts, suction, epinephrine / amiodarone when ALS gives drugs.
- ROSC time, post-ROSC vitals, and handover to receiving team.
- Complete local cardiac arrest audit forms and incident reporting as required.
Complications and common errors
- Delayed compressions due to prolonged pulse checks or misreading agonal breathing.
- Shallow or slow compressions from rescuer fatigue—rotate before quality falls.
- Excessive ventilation reducing coronary perfusion pressure.
- Rib or sternal injury—acceptable risk in arrest; document if suspected after ROSC.
- Failed pad adhesion from wet or hairy chest—dry and shave pad sites only if delays are minimal.
When to escalate
- Any confirmed or suspected arrest—immediate cardiac arrest activation plus BLS.
- No ROSC after multiple cycles—continue per ALS until team decision; ensure reversible causes are communicated.
- Suspected anaphylaxis as trigger—mention exposure and need for adrenaline alongside CPR.
- Persistent hypoxia after ROSC—urgent medical review and critical care referral.
Clinical pearls
- Compress on the sternum, not the abdomen. Hand placement drifts under fatigue.
- Delegate the phone call so the first compressor does not leave the chest.
- Metronomes save rate when adrenaline is high; depth still needs active coaching.
- Re-audit skills annually—compression fraction collapses faster than teams expect.
NCLEX practice questions
Rehearse ward arrest decisions with NCLEX-style clinical judgment practice for adult basic life support: a shared resuscitation vignette, priority action, select-all-that-apply recognition, post-shock trend interpretation, matrix escalation matching, ordered BLS sequence, and arrest documentation cloze (recognise cues → analyse → prioritise → act → evaluate outcomes).
Unfolding case — acute medical ward, day shift. Ms. Hartley, 67, was found unresponsive in bed. She does not respond to voice or sternal rub. You see occasional gasping breaths without chest rise. SpO2 unreadable on the finger probe. The crash trolley and AED are being brought. You are BLS-certified.
Answer key & rationale
Frequently asked questions
How long should I check breathing?
No more than 10 seconds. If breathing is absent or abnormal—including gasping—start compressions and apply the AED when it arrives.
Should I check a pulse before compressions?
Healthcare providers should not delay compressions for prolonged pulse checks when arrest is suspected. If you cannot quickly confirm signs of life, start CPR.
What if I cannot give rescue breaths?
Provide continuous chest compressions and use the AED. Add ventilations when trained staff and equipment are available without long pauses.
When should compressors swap?
About every two minutes or sooner if depth or rate falls—plan the swap before fatigue degrades quality.
Can I use an AED on a wet chest?
Dry the chest quickly. Remove medication patches from pad sites. Do not delay compressions for extensive grooming.
Does this page cover paediatric BLS?
No. Children and infants need different compression depths, ratios, and pad options—use paediatric resuscitation training.
References
- Royal Marsden Manual of Clinical Nursing Procedures — Basic life support (defibrillation during CPR; RMM Online).https://www.rmmonline.co.uk/manual/c12-fea-0026
- Royal Marsden Manual — Procedures hub (general nursing procedure library).https://www.rmmonline.co.uk/contents/procedures
- Resuscitation Council UK. 2025 Resuscitation Guidelines — Adult basic and advanced life support.https://www.resus.org.uk/library/2025-resuscitation-guidelines/adult-basic-and-advanced-life-support
- American Heart Association. 2025 CPR and ECC Guidelines — Adult Basic Life Support.https://cpr.heart.org/en/resuscitation-science/cpr-and-ecc-guidelines/adult-basic-life-support
- European Resuscitation Council. Guidelines 2025: Adult basic life support (Resuscitation supplement; DOI).https://doi.org/10.1016/j.resuscitation.2025.110752
- NHS England. Resuscitation policy and standards (national context for hospital CPR systems).https://www.england.nhs.uk/publication/resuscitation-policy-and-standards/
- OpenStax. Clinical Nursing Skills — emergency and resuscitation fundamentals.https://openstax.org/details/books/clinical-nursing-skills
If someone collapses, is unresponsive, and is not breathing normally, call your local emergency number immediately. Push hard and fast in the centre of the chest (100–120 presses per minute) and use a public AED if available—the device gives spoken instructions. Untrained callers should follow dispatcher coaching where offered.
Editorial standards and medical review
About the author: Sid A. Abdala Balal, RN, Resuscitation Link Officer, writes evidence-based nursing education focused on emergency response, patient safety, and practical bedside skills.
Medical review: This guide is reviewed by Dr. Adam Sayedi, MD, for clinical accuracy, clarity, and alignment with current adult BLS and AED guidance.
Policies: Medical Review Process · Editorial Policy · Correction Policy