Advanced Life Support (ALS)

Advanced Life Support (ALS): Cardiac Arrest, Defibrillation and Post-ROSC Care

Why this matters: Advanced life support is a coordinated response to cardiac arrest and peri-arrest deterioration. The EMT must recognise arrest early, start high-quality CPR, use an AED/defibrillator safely, obtain vascular access when trained, identify reversible causes, support airway/ventilation and deliver a structured handover after return of spontaneous circulation (ROSC).

Safety and scope: Follow current AHA/ERC guidance, the Uganda Clinical Guidelines, equipment-specific instructions and your authorised scope. Drug concentrations, shock energies and pacing settings vary by system. ALS is team care: call for help early, assign roles and never allow a medication or airway task to delay compressions and defibrillation.

Learning outcomes

Recognise cardiac arrest and distinguish shockable from non-shockable rhythms.
Deliver effective CPR, defibrillation and ventilation with minimal interruptions.
Use a team-based ALS cycle, identify reversible Hs and Ts, and administer protocol-led medicines.
Recognise peri-arrest bradycardia and tachyarrhythmia requiring pacing, cardioversion or specialist escalation.
Provide structured post-ROSC care, including oxygenation, blood pressure, ECG, temperature and neurological protection.
Document timing, rhythm, shocks, medicines, airway, ETCO2 and response for clinical governance.

1. Recognising cardiac arrest

Ensure scene safety and use PPE.
Check responsiveness and normal breathing. Occasional gasps are agonal, not effective breathing.
Call for the resuscitation team/AED and check a central pulse only if trained; do not delay CPR for prolonged pulse searching.
Start compressions immediately when there is no normal breathing and no definite pulse.
Attach defibrillator/AED pads as soon as available while CPR continues.

Cardiac-arrest clock: Every minute without CPR and defibrillation lowers survival. Start compressions, attach pads, analyse rhythm and shock when indicated—then resume CPR immediately.

2. High-quality CPR

Element	Adult target/principle	Common error
Rate	100–120 compressions per minute.	Too slow, too fast or irregular.
Depth	At least 5 cm but avoid excessive depth; allow full recoil.	Shallow compressions or leaning on the chest.
Location	Centre of the chest/lower half of sternum on a firm surface.	Hands too high, too low or over the xiphisternum.
Interruptions	Keep pauses as short as possible, ideally under 10 seconds for rhythm checks/shock.	Long pauses for intubation, pulse checks or drug preparation.
Ventilation	Without advanced airway: 30 compressions to 2 breaths. With advanced airway: continuous compressions and one breath about every 6 seconds when protocolled.	Hyperventilation, excessive volume or failure to ventilate.
Switch compressor	Every about 2 minutes or sooner if fatigue, without pausing compressions.	Quality falls while the team hesitates to rotate.

3. Team roles and closed-loop communication

Team leader: overall plan, rhythm interpretation, reversible causes and decisions.
Compressor: high-quality compressions; announces fatigue and switches smoothly.
Airway/ventilation: mask seal, oxygen, adjunct/advanced airway, ventilation and capnography.
Defibrillator operator: pads, rhythm analysis, charging, safety checks and shock delivery.
Medication/access: IV/IO access, preparation, timing and flushes according to protocol.
Recorder: times compressions, rhythm checks, shocks, medicines, ETCO2, ROSC and handover.

Closed loop: The leader gives a named task; the receiver repeats it; the receiver reports completion and result. This prevents unrecognised missed adrenaline, unsafe shocks and duplicate doses.

4. Defibrillation and rhythm categories

Rhythm	Meaning	Immediate action
VF / pulseless VT	Chaotic or rapid ventricular electrical activity with no effective pulse.	Shock as soon as safely possible, then immediate CPR for about 2 minutes before re-analysis.
Asystole	No meaningful ventricular electrical activity.	CPR, adrenaline as protocolled, search reversible causes; do not shock asystole.
PEA	Organised electrical activity without a palpable pulse.	CPR, adrenaline and aggressive search for Hs and Ts; treat the cause.

5. Shockable rhythm cycle: VF/pulseless VT

Continue CPR while pads are attached; ensure everyone is clear before analysis and shock.
Deliver the manufacturer/protocol-recommended biphasic shock. Keep oxygen sources away from the chest and announce “all clear.”
Immediately resume CPR for about two minutes—do not pause to check a pulse unless there are signs of ROSC.
Obtain IV/IO access, give protocol-led adrenaline/epinephrine after the appropriate shock cycle and repeat at the recommended interval.
For persistent VF/pVT after further shocks, consider an antiarrhythmic such as amiodarone or lidocaine according to local ALS protocol.
Search for reversible causes throughout: hypoxia, hypovolaemia, electrolytes, hypothermia, tension pneumothorax, tamponade, toxins, thrombosis and trauma.

6. Non-shockable rhythm cycle: PEA/asystole

Start/continue CPR and confirm the rhythm in more than one lead or pad position when possible.
Give adrenaline/epinephrine as soon as IV/IO access is available according to protocol, then repeat at the authorised interval.
Do not waste time attempting defibrillation for true asystole.
Use capnography, ultrasound where available and clinical signs to assess CPR quality and reversible causes.
Reanalyse rhythm every about two minutes; if it becomes shockable, switch immediately to the shockable pathway.

7. Defibrillator safety

Dry the chest, remove medication patches and place pads with adequate separation; avoid placing directly over an implanted device.
Ensure no one is touching the patient, bed, oxygen tubing or stretcher during analysis and shock.
Keep hands and oxygen away from the shock field; follow the device’s charging and shock-confirmation sequence.
Resume compressions immediately after the shock and minimise pauses for rhythm checks.
Record energy, shock number, rhythm and response; a failed shock may reflect pad contact, severe hypoxia, acidosis, low energy or a non-shockable rhythm.

8. Advanced airway and ventilation in ALS

Start with effective BVM ventilation and an airway adjunct. An SGA or endotracheal tube may be considered by a competent provider without interrupting compressions for more than a brief interval. Continuous waveform capnography is used to confirm and monitor tube placement and CPR quality. Once an advanced airway is in place, avoid excessive ventilation: continuous compressions and slow, regular breaths according to the current protocol.

Sign	Meaning during CPR	Action
Sudden ETCO2 rise	Possible ROSC, improved circulation or change in compression quality.	Check pulse and rhythm without prolonging a pause; continue post-ROSC care if circulation returned.
Low/falling ETCO2	Poor compressions, inadequate perfusion, hyperventilation, disconnection or prolonged arrest.	Improve compression quality, check circuit/airway, avoid hyperventilation and reassess causes.
Absent waveform	Dislodged tube, oesophageal placement, disconnection, apnoea or very low flow.	Ventilate by BVM, inspect equipment and confirm placement immediately.

9. Vascular access and ALS medicines

Medicine/intervention	Role	Safety and monitoring
Adrenaline/epinephrine	Improves coronary/cerebral perfusion pressure during arrest; used on the shockable or non-shockable pathway at protocolled intervals.	Use the correct concentration and route. Record every dose/time; do not give repeated unrecorded doses.
Amiodarone or lidocaine	Considered for refractory VF/pVT after shocks according to local algorithm.	Monitor rhythm, blood pressure and cumulative dose; correct hypoxia/electrolytes.
Magnesium	Selected torsades de pointes or specific electrolyte-related arrhythmia.	Not routine for every arrest; monitor renal function and rhythm.
Calcium/bicarbonate	Only for specific indications such as hyperkalaemia, calcium-channel blocker toxicity or severe sodium-channel blockade.	Routine use in undifferentiated arrest is not recommended; obtain senior/toxicology guidance.
IV/IO access	Allows rapid medicine/fluid delivery when IV is difficult.	Secure line, flush according to protocol and document site/complications.

10. Reversible causes: Hs and Ts

Cause	Clues	Targeted action
Hypoxia	Low SpO2 before arrest, airway obstruction, chest disease, absent ventilation.	Open/suction airway, oxygenate, ventilate, confirm device and treat the cause.
Hypovolaemia	Bleeding, dehydration, burns, weak pulse, flat veins, trauma.	Control bleeding, IV/IO access, warmed crystalloid/blood protocol and rapid source control.
Hydrogen ion (acidosis)	Prolonged arrest, renal failure, shock, DKA or toxin exposure.	High-quality CPR/ventilation and treat cause; bicarbonate only for specific indications.
Hypo-/hyperkalaemia/metabolic	Weakness, renal disease, dialysis, ECG changes, medication exposure.	Point-of-care/lab testing and protocol-led calcium, insulin/glucose, bicarbonate or other therapy.
Hypothermia/hyperthermia	Abnormal core temperature, environmental exposure, drug toxicity, sepsis.	Measure core temperature and use controlled rewarming/cooling.
Tension pneumothorax	Sudden unilateral absent breath sounds, distended neck veins, shock, high airway pressure.	Immediate decompression by trained provider; do not wait for imaging in arrest.
Tamponade	Trauma, muffled heart sounds, raised venous pressure, PEA, narrow pulse pressure.	Urgent ultrasound/surgical or pericardial intervention by specialists.
Toxins	Packets, pupils, unusual ECG, seizures, exposure history or multiple victims.	PPE, decontamination, poison-centre advice and toxin-specific antidotes.
Thrombosis—pulmonary	Sudden collapse, hypoxia, risk factors, PEA, signs of DVT.	Consider thrombolysis or embolectomy pathway with senior team.
Thrombosis—coronary	Ischaemic symptoms, ST elevation, ventricular arrhythmia.	Post-ROSC ECG and urgent reperfusion pathway.
Trauma	External/internal bleeding, chest injury, head injury.	Haemorrhage control, airway/ventilation, pelvic/limb stabilisation and trauma-centre transfer.

11. Peri-arrest bradycardia

Bradycardia matters when it causes hypotension, altered mental state, shock, ischaemic chest discomfort or acute heart failure. First correct hypoxia, review medicines and look for myocardial infarction, electrolyte problems or conduction disease.

Assess airway/breathing/circulation, attach ECG/BP/SpO2 and obtain IV/IO access.
Give atropine or other first-line treatment only according to local protocol and contraindications.
If unstable or unresponsive to initial therapy, prepare transcutaneous pacing and/or infusion support by an authorised clinician.
Provide analgesia/sedation for pacing when safe, but never delay lifesaving electrical support.
Escalate early for transvenous pacing or specialist care.

12. Peri-arrest tachyarrhythmia

Pattern	Assessment	Immediate direction
Unstable tachycardia with pulse	Shock, hypotension, altered mental state, ischaemic chest pain or acute heart failure.	Synchronised cardioversion by trained clinician; sedate if feasible without delaying shock.
Stable narrow-complex regular tachycardia	Regular rhythm, often sudden onset; check ECG and cause.	Vagal manoeuvres/adenosine only by protocol and monitoring; seek senior review.
Stable atrial fibrillation/flutter	Irregular or saw-tooth rhythm; assess duration, anticoagulation and cause.	Rate/rhythm strategy and anticoagulation decisions are clinician-led.
Wide-complex tachycardia	Assume VT until proven otherwise, especially with structural heart disease.	Urgent expert review; avoid inappropriate AV-nodal blockade in pre-excited AF.

13. ROSC recognition

Sudden organised rhythm with a palpable central pulse.
Abrupt rise in ETCO2, spontaneous breathing, purposeful movement or improved skin perfusion.
Do not stop compressions solely because the monitor shows an organised rhythm; check a pulse and signs during a brief pause.

14. Immediate post-ROSC care

Airway: maintain patency; use an advanced airway only when it can be confirmed and monitored without compromising oxygenation.
Breathing: titrate oxygen to the prescribed target, avoid both hypoxaemia and unnecessary hyperoxia, and use capnography/ABG where available.
Circulation: continuous ECG/BP, IV/IO access, fluids/vasopressors as directed and treatment of shock.
12-lead ECG: identify STEMI or other cause and activate the reperfusion pathway.
Disability: glucose, pupil/neurological assessment, seizure recognition and sedation/analgesia review.
Temperature and brain protection: prevent fever, manage seizures and follow the receiving critical-care protocol.
Cause and destination: identify the reason for arrest, communicate resuscitation details and transfer to a capable hospital.

15. ALS after cardiac arrest in special circumstances

Situation	Key modification
Pregnancy	Call obstetric/neonatal help, optimise left uterine displacement, early airway support and follow maternal arrest protocol.
Trauma	Control catastrophic bleeding, address airway/chest injury and consider resuscitative thoracostomy or surgery by trained teams.
Drowning	Ventilation is especially important; remove from water safely, manage hypothermia and consider cervical injury by mechanism.
Hyperkalaemia	Look for renal failure/dialysis and peaked T waves/wide QRS; give calcium and shifting therapy only per protocol.
Opioid/toxin arrest	PPE, airway/ventilation, antidote when indicated and protect rescuers from contamination.
Hypothermia	Measure core temperature, handle gently, rewarm while continuing resuscitation and use local temperature-specific algorithm.

16. Clinical scenarios

Scenario 1 — Witnessed VF: A patient collapses in a clinic, has agonal gasps and VF on the monitor. Start CPR, charge and shock safely, resume compressions immediately, establish IV/IO access, give protocol-led medicines and reassess every cycle while searching reversible causes.

Scenario 2 — PEA after trauma: A motorcyclist is pulseless with organised electrical activity, distended neck veins and absent left breath sounds. Continue CPR, ventilate, call for immediate chest decompression by the trained provider and control haemorrhage—do not waste time shocking PEA.

Scenario 3 — ROSC in the ambulance: ETCO2 rises suddenly and a pulse returns. Stop compressions briefly to confirm, secure the airway, titrate oxygen, support blood pressure, obtain ECG/glucose, prevent fever and give a complete handover.

Scenario 4 — Bradycardic collapse: An inferior-MI patient has HR 30, hypotension and confusion. Oxygenate, monitor, obtain access, follow the bradycardia algorithm and prepare pacing while the senior clinician treats the cause.

Scenario 5 — Refractory VF: VF persists after shocks and adrenaline. Check pad contact, compression quality, oxygenation, electrolytes, toxins and coronary thrombosis; give an antiarrhythmic only through the authorised protocol and continue high-quality CPR.

17. Resuscitation documentation

Collapse/witnessed status, bystander CPR, first rhythm and time CPR started.
Every rhythm check and shock: time, rhythm, energy/device and response.
Compression quality, pauses, compressor changes, airway devices, ventilation and capnography.
IV/IO sites, medicines/concentrations/doses/times, fluids and adverse effects.
Reversible causes considered/treated and consultations made.
ROSC time, vital signs, ECG, glucose, neurological status, airway confirmation and destination.

18. Revision questions

What are the differences between VF/pVT and PEA/asystole management?
Why must compressions resume immediately after a shock?
List the Hs and Ts and give one bedside clue for each.
What does a sudden ETCO2 rise suggest during CPR?
Why is routine calcium or bicarbonate not given in every arrest?
What findings make a tachyarrhythmia “unstable”?
What are the first post-ROSC priorities?
Why is closed-loop communication important in ALS?
When should a rescue airway be used instead of repeated intubation attempts?
Which details must appear in a resuscitation record?

19. Key take-home points

High-quality CPR and early defibrillation are the foundations of ALS.
Shock VF/pVT; do not shock true asystole or PEA.
Use waveform capnography to confirm airway placement, monitor CPR and recognise possible ROSC.
Search for and treat reversible causes throughout every arrest cycle.
After ROSC, protect oxygenation, ventilation, blood pressure, temperature and the brain while treating the cause.
A disciplined team, accurate timing and clear handover are clinical interventions, not paperwork.

Selected authoritative resources

For EMT practice: Start early, compress well, shock safely, ventilate effectively, think Hs and Ts, and treat ROSC as the beginning of critical care—not the end of resuscitation.