Advanced Life Support (ALS) for Paramedics

Advanced Life Support: What Every UK Paramedic Needs to Know

Advanced Life Support (ALS) sits at the very core of paramedic practice. Whether you are a student paramedic on placement or preparing for your final OSCEs, understanding the ALS algorithm — and being able to apply it under pressure — is non-negotiable. This article walks through the key components of ALS in the UK pre-hospital context, aligned with Resuscitation Council UK (RCUK) guidelines and JRCALC clinical practice.

The ALS Algorithm: A Framework Under Pressure

The RCUK ALS algorithm provides a structured approach to managing cardiac arrest in adults. It is designed to be followed even in the most chaotic pre-hospital environments, giving the resuscitation team a shared mental model. The algorithm divides cardiac arrest rhythms into two groups:

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

Rhythm recognition is therefore a foundational skill. You must be able to identify these rhythms rapidly and correctly on a monitor to determine which pathway to follow. Misidentifying a rhythm — for example, treating fine VF as asystole — can directly cost a patient their life.

High-Quality CPR: The Non-Negotiable Foundation

No drug, no shock, and no airway adjunct replaces high-quality CPR. The evidence base is clear: adequate compression depth, rate, and recoil are the primary determinants of survival from cardiac arrest.

The RCUK standards for CPR quality are:

• Compression rate: 100–120 per minute
• Compression depth: 5–6 cm
• Full chest recoil between compressions
• Minimise interruptions — aim for a pre-shock pause of less than 5 seconds
• Avoid hyperventilation once an advanced airway is in place (aim for 10 breaths/min)

On scene, you should rotate the compressor role every two minutes to maintain quality. Fatigue sets in faster than most clinicians expect, and poor-quality compressions are often invisible to the person performing them.

Defibrillation: Timing and Energy

For shockable rhythms, early defibrillation is critical. Each minute of delay to defibrillation in VF reduces the chance of survival by approximately 10%. In the pre-hospital setting, this makes your response time and your ability to attach a defibrillator quickly genuinely life-saving actions.

Key defibrillation points for UK paramedics:

• Biphasic defibrillators are standard — follow the manufacturer's recommended energy (typically 150–200 J for the first shock, then escalate if needed)
• Deliver one shock, then immediately resume CPR — do not pause to check the rhythm
• Reassess rhythm every 2 minutes
• If VF/pVT persists after three shocks, consider amiodarone

Drugs in ALS: What, When, and Why

Pharmacological intervention in ALS is important, but it comes after high-quality CPR and defibrillation in terms of priority. The main drugs used in UK pre-hospital ALS are:

Adrenaline (Epinephrine)

Adrenaline 1 mg IV/IO is given every 3–5 minutes throughout the arrest. For non-shockable rhythms, it is given as soon as IV/IO access is established. For shockable rhythms, it is given after the third shock. Its primary benefit is improving coronary and cerebral perfusion pressure during CPR, increasing the likelihood of achieving ROSC.

Amiodarone

Amiodarone 300 mg IV/IO is given after the third shock in refractory VF/pVT. A further 150 mg dose can be given after the fifth shock. It works as a membrane-stabilising antiarrhythmic, helping to establish a stable rhythm post-defibrillation.

Other Considerations

Depending on the clinical picture, you may also consider:

• Sodium bicarbonate — in prolonged arrest, hyperkalaemia, or tricyclic antidepressant overdose
• Calcium chloride — in hyperkalaemia, hypocalcaemia, or calcium channel blocker toxicity
• Magnesium — in Torsades de Pointes or suspected hypomagnesaemia

Airway Management During ALS

Airway management in ALS has evolved significantly. Current RCUK guidance does not mandate tracheal intubation as the first-line advanced airway. A supraglottic airway device (SAD), such as the i-gel, is often more appropriate in the pre-hospital setting, particularly where intubation would cause prolonged interruptions to CPR.

Once an advanced airway is in place, compressions and ventilations are no longer synchronised — compressions are continuous at 100–120/min, and ventilations are delivered at 10 breaths per minute. Waveform capnography (EtCO2) must be used to confirm airway placement and monitor CPR quality. A persistently low EtCO2 (below 10 mmHg) suggests poor CPR quality, while a sudden rise may indicate ROSC.

The 4Hs and 4Ts: Treating Reversible Causes

ALS is not just about the algorithm — it is about identifying and treating the underlying cause of the arrest. The reversible causes are grouped into the 4Hs and 4Ts:

• Hypoxia — ensure effective oxygenation
• Hypovolaemia — consider IV fluid and haemorrhage control
• Hypo/Hyperkalaemia and metabolic disorders — consider bloods and history
• Hypothermia — do not confirm death until warm and dead
• Thrombosis (coronary or pulmonary) — consider thrombolytics in PE
• Tension pneumothorax — needle thoracocentesis
• Tamponade (cardiac) — consider mechanism and history
• Toxins — antidotes where available (e.g. naloxone for opioids)

In pre-hospital practice, your clinical history, scene assessment, and mechanism of injury provide vital clues to the likely reversible cause. Do not become so focused on the algorithm that you miss a tension pneumothorax or a patient who has overdosed on insulin.

Post-ROSC Care

Achieving return of spontaneous circulation (ROSC) is not the end — it is the beginning of the next phase. In the pre-hospital environment, post-ROSC priorities include:

• Maintaining SpO2 94–98% and avoiding hyperoxia
• Targeting EtCO2 35–45 mmHg to avoid hypo/hypercapnia
• 12-lead ECG to identify ST elevation — STEMI requires urgent cath lab activation
• Preventing hypotension — target systolic BP above 100 mmHg
• Avoiding hyperthermia — temperature management is a hospital intervention but monitoring begins pre-hospital

Developing Competence in ALS

Confidence in ALS comes from repetition, reflection, and deliberate practice. Simulation, case-based learning, and regular review of guidelines all contribute to building the kind of pattern recognition that allows you to lead a resuscitation calmly and effectively. Understanding not just what to do, but why — the pharmacology, physiology, and evidence behind each intervention — is what separates a competent technician from a genuinely skilled clinician.