Advanced Life Support (ALS) for Paramedics

What Is Advanced Life Support?

Advanced Life Support (ALS) refers to the set of clinical interventions used to manage cardiac arrest and peri-arrest conditions when basic life support alone is insufficient. For UK paramedics, ALS forms one of the most critical competencies in pre-hospital emergency care. Whether you are a student paramedic on placement or a newly qualified practitioner, understanding the ALS algorithm — and being able to apply it under pressure — is non-negotiable.

In the UK, ALS guidance is primarily drawn from the Resuscitation Council UK (RCUK) guidelines, which are periodically updated to reflect the latest evidence. Paramedics must also be familiar with JRCALC (Joint Royal Colleges Ambulance Liaison Committee) protocols, which contextualise these guidelines for the pre-hospital environment.

The ALS Algorithm: A Structured Overview

The ALS algorithm is built around the principle of early rhythm recognition, high-quality CPR, and the systematic identification and treatment of reversible causes. The process begins the moment a cardiac arrest is confirmed.

Step 1: Confirm Cardiac Arrest and Begin CPR

Upon confirming unresponsiveness and absent normal breathing, you should immediately begin CPR at a ratio of 30 compressions to 2 ventilations. Chest compressions should be delivered at a rate of 100–120 per minute, with a depth of 5–6 cm. Minimising interruptions to compressions is one of the strongest predictors of positive outcomes in out-of-hospital cardiac arrest (OHCA).

Step 2: Attach a Monitor and Analyse the Rhythm

As soon as possible, attach a defibrillator or cardiac monitor. The rhythm will fall into one of two categories:

• Shockable rhythms: Ventricular Fibrillation (VF) and pulseless Ventricular Tachycardia (pVT)
• Non-shockable rhythms: Pulseless Electrical Activity (PEA) and Asystole

This distinction drives the entire algorithm and determines whether defibrillation is the next priority.

Step 3: Shockable Rhythms — Defibrillation

If the rhythm is VF or pVT, deliver a single unsynchronised DC shock. For biphasic defibrillators — which are standard in UK ambulance services — the initial energy is typically 150–200 J, followed by 150–360 J for subsequent shocks, depending on the manufacturer's guidance. After each shock, immediately resume CPR for two minutes before re-analysing the rhythm. Do not delay CPR to check for a pulse after defibrillation.

Adrenaline 1 mg IV is given after the third shock, and then every 3–5 minutes thereafter. Amiodarone 300 mg IV is also administered after the third shock, with a further 150 mg dose after the fifth shock if the patient remains in a shockable rhythm.

Step 4: Non-Shockable Rhythms — Focus on Reversible Causes

In PEA or asystole, defibrillation is not indicated. The priority is high-quality CPR and the rapid identification of reversible causes. Adrenaline 1 mg IV should be given as soon as IV or IO access is established, and repeated every 3–5 minutes. There is no role for amiodarone in non-shockable rhythms.

The 4 Hs and 4 Ts: Reversible Causes of Cardiac Arrest

A central pillar of ALS is the systematic search for and treatment of reversible causes, summarised as the 4 Hs and 4 Ts. In the pre-hospital setting, you may not be able to treat every cause immediately, but recognition is the first step.

• Hypoxia — Ensure effective ventilation with high-flow oxygen
• Hypovolaemia — Consider haemorrhage or dehydration; establish IV access and consider fluid bolus
• Hypo/Hyperkalaemia and metabolic disorders — Consider renal failure, diabetic emergencies
• Hypothermia — Use a low-reading thermometer; consider active rewarming
• Tension pneumothorax — Perform needle thoracocentesis (2nd intercostal space, midclavicular line, or 4th/5th intercostal space, anterior axillary line)
• Tamponade — Difficult to manage pre-hospital; consider in penetrating chest trauma
• Toxins — Review the clinical history; naloxone for opioid toxicity, consider specific antidotes
• Thrombosis — Pulmonary embolism or acute MI; thrombolysis may be considered in hospital

Airway Management in ALS

Effective airway management is essential throughout resuscitation. UK paramedics are trained in a range of airway adjuncts, from oropharyngeal and nasopharyngeal airways to supraglottic airway devices (SGAs) such as the i-gel. Tracheal intubation may also be performed by appropriately trained and credentialled paramedics, though RCUK guidance emphasises that intubation attempts should not interrupt CPR for more than five seconds.

Waveform capnography (end-tidal CO₂ monitoring) should be used to confirm correct airway placement and can also provide prognostic information during resuscitation — a persistently low ETCO₂ despite good CPR may indicate a poor prognosis.

Vascular Access and Drug Administration

IV access should be attempted early, but if it cannot be established promptly, intraosseous (IO) access is a reliable and rapid alternative. The tibia and humerus are common IO sites in adults. Drug doses and pharmacokinetics are equivalent via the IO route, making it a valuable tool in cardiac arrest management.

Post-Resuscitation Care

If return of spontaneous circulation (ROSC) is achieved, the priorities shift to stabilisation and safe transfer. Key considerations include:

• Targeting SpO₂ of 94–98% — avoid hyperoxia
• Targeting a systolic blood pressure of ≥100 mmHg
• Obtaining a 12-lead ECG to identify STEMI or other cardiac causes
• Maintaining normoglycaemia
• Communicating a clear handover to the receiving team, including downtime, interventions, and drug history

Temperature management and targeted temperature management (TTM) decisions are made in hospital, but pre-hospital teams should avoid actively rewarming post-arrest patients unless hypothermia was the primary cause.

Practising ALS as a Student Paramedic

Understanding the algorithm on paper is one thing — applying it in a high-stress, time-pressured environment is another. Simulation, repeated scenario practice, and testing yourself on rhythm recognition and drug calculations are all essential preparation. The more familiar you are with the algorithm, the more cognitive bandwidth you have to manage the clinical nuances of a real arrest.