Introduction to Basic Life Support
This overview is based on current Australian and New Zealand Committee on Resuscitation (ANZCOR) guidelines, which inform evidence-based basic life support practice across Australian healthcare settings.
Basic life support (BLS) refers to the immediate assessment and interventions used to recognise and respond to life-threatening emergencies, particularly those involving airway obstruction, respiratory compromise, or cardiac arrest. It provides a structured approach to preserving life until recovery occurs or more advanced interventions become available. In healthcare settings, BLS is not limited to cardiac arrest scenarios. It may be initiated in response to sudden collapse, respiratory arrest, choking, unresponsiveness, or significant clinical deterioration where airway, breathing, or circulation are immediately compromised.
BLS forms a foundational component of clinical practice across many healthcare environments, including hospitals, aged care, community settings, and emergency care. Recognising that timely intervention can significantly influence patient outcomes, particularly when oxygen delivery to vital organs is compromised, is essential to understanding the significance of administering BLS interventions.
Although BLS follows a standard framework, its application may vary depending on the clinical context, available resources, and the healthcare professional’s scope of practice. A nurse in an acute care ward, for example, may initiate oxygen therapy, airway positioning, and emergency escalation, whereas a community healthcare worker may be limited to more basic interventions, depending on resources available, while awaiting emergency services.
What You Need to Know
Basic life support follows a structured framework designed to guide rapid assessment and intervention in life-threatening situations. A common approach to this framework is using DRSABCD, which provides a clear sequence for responding safely and effectively. DRSABCD stands for:
Danger – Assess the environment for hazards before approaching the patient. This includes risks to yourself, the patient, and others nearby. Personal safety comes first; do not enter an unsafe environment until risks have been controlled or assistance is available.
Response – Check whether the patient is conscious and responsive. A lack of response may indicate severe deterioration requiring urgent intervention. This step is often referred to as “talk and touch”; speak loudly and clearly to the patient, and if they do not respond, apply gentle physical stimulation, such as lightly shaking their shoulder, to assess responsiveness.
Send for help – Activate the emergency response system immediately. In healthcare settings, this may involve, requesting immediate assistance from the nurse in charge or treating doctor, pressing the emergency button (if available), initiating a medical emergency call (MET call) or escalating according to local protocols.
Airway – Assess whether the airway is open and clear. Airway obstruction prevents oxygen from reaching the lungs and requires immediate management. Open the patient’s mouth and visually inspect for any obvious obstruction, such as vomit, food, blood, or a foreign object, that may be blocking the airway.
Breathing – Look, listen, and assess for normal breathing. Agonal breathing or absent respirations should be treated as an emergency. This step is often remembered as “look, listen and feel”, look for rise and fall of the chest, listen for breath sounds and note any abnormal sounds (such as gasping, stridor, snoring, or gurgling, all of which require immediate escalation), and feel for airflow against your hand or cheek to assess whether the patient is breathing normally.
CPR – If the patient is not breathing normally, commence cardiopulmonary resuscitation according to current guidelines.
Defibrillation – Apply an automated external defibrillator (AED) or manual defibrillator as soon as available if indicated.
A rapid BLS assessment aims to identify immediately reversible life threats, such as airway obstruction, respiratory arrest, or cardiac arrest.
BLS is designed to be systematic because emergencies are high-pressure situations where missed steps can delay care. Following a structured approach reduces cognitive overload, improves team coordination, and supports consistent decision-making under pressure.
Beyond the Basics
Basic life support and advanced life support (ALS) share the same overarching goal of preserving life, but they differ significantly in complexity, scope, and the interventions involved.
BLS focuses on immediate foundational interventions, including airway management, ventilation support, CPR, and early defibrillation (often with an Automatic External Defibrillator (AED)). These actions are designed to stabilise the patient in the critical first moments of deterioration or collapse. ALS builds on this by incorporating advanced assessment, cardiac rhythm interpretation, medication administration, advanced airway management, and coordinated medical resuscitation interventions.
The distinction between BLS and ALS is important because scope of practice varies considerably between healthcare worker roles and clinical settings. Not all nurses are trained or authorised to perform advanced interventions. Safe clinical practice requires working within local policy, organisational protocols, and individual competency. Attempting interventions outside scope can compromise patient safety, even in emergencies.
Basic life support may also include the use of simple airway adjuncts, depending on the clinician’s training, scope of practice, and clinical setting. Airway adjuncts are devices designed to help maintain airway patency by preventing obstruction, such as an oropharyngeal airway (OPA) or nasopharyngeal airway (NPA).
Common airway adjuncts include:
Oropharyngeal airway (OPA) – used in unconscious patients without a gag reflex to help maintain airway patency
Nasopharyngeal airway (NPA) – may be used in selected patients where an OPA is unsuitable and local scope permits
Bag-valve-mask ventilation (BVM) – used to provide assisted ventilation in patients with inadequate or absent respirations
Laryngeal mask airway (LMA) –a temporary supraglottic airway device used in emergency care and theatre settings to maintain a patent airway by sitting above the laryngeal inlet and facilitating ventilation without requiring endotracheal intubation.
Suction equipment – used to remove secretions, vomitus, or visible obstruction from the airway where available
These interventions require both technical skill and clinical judgement. An airway adjunct used incorrectly can worsen obstruction or delay escalation.
BLS also involves recognising when a patient has not yet arrested but is clearly deteriorating. A patient with increasing respiratory distress, altered consciousness, or airway compromise may require immediate BLS-style interventions before a full cardiac arrest occurs. Early recognition is often what prevents progression to a more critical event.
In Practice
Scenario 1: Cardiac arrest on a medical ward
A 68-year-old patient recovering from myocardial infarction suddenly becomes unresponsive while speaking with staff. The nurse checks for responsiveness, identifies absent normal breathing, activates the emergency response system, and commences CPR while another staff member retrieves the defibrillator. Basic life support continues until the resuscitation team arrives and advanced life support interventions begin.
This is the most recognisable application of BLS, where immediate compressions and early defibrillation are critical.
Scenario 2: Choking in aged care
An elderly resident begins coughing forcefully during lunch, then becomes unable to speak or breathe effectively. Staff rapidly assess the situation, recognise severe airway obstruction, and initiate appropriate choking management while calling for urgent assistance.
In this setting, BLS principles focus on airway emergency recognition and immediate intervention before progression to respiratory or cardiac arrest.
Scenario 3: Respiratory deterioration in a postoperative patient
A patient several hours after surgery becomes increasingly drowsy, with shallow respirations and falling oxygen saturations following opioid administration. The nurse recognises early deterioration, repositions the airway using an appropriate BLS airway manouvre, applies oxygen, assesses breathing, escalates urgently by calling for immediate assistance, and prepares airway support equipment.
Although the patient has not arrested, BLS principles are still being applied through airway management, breathing support, and rapid escalation.
Basic life support is often associated with dramatic emergencies, but in practice, its principles are applied whenever airway, breathing, or circulation are immediately threatened. Strong BLS skills rely not only on technical knowledge, but on rapid recognition, structured assessment, and timely action.
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