🩺 Basic Life Support

Basic Life Support (BLS) is the systematic approach to treating cardiac arrest in the absence of advanced equipment. It focuses on maintaining airway patency and providing manual ventilation and circulation through chest compressions. In the UK, BLS follows the Resuscitation Council UK guidelines, emphasizing high-quality compressions with minimal interruptions. It is a mandatory skill for all UK healthcare students and professionals, forming the first critical link in the Chain of Survival.

Basic Life Support is indicated for any individual who is unresponsive and not breathing normally (or only having occasional agonal gasps). It is the immediate management for cardiac arrest, regardless of the underlying cause (e.g., myocardial infarction, drowning, or trauma). Rapid recognition and initiation are critical, as every minute of delay reduces the probability of survival by approximately 10%. BLS acts as a bridge to Advanced Life Support (ALS) by maintaining minimal cerebral and coronary perfusion.

The only absolute contraindications to starting BLS are the presence of a valid, applicable 'Do Not Attempt Cardiopulmonary Resuscitation' (DNACPR) order or a Recommended Summary Plan for Emergency Care and Treatment (ReSPECT) form stating CPR is not to be performed. BLS should also not be initiated if there are obvious signs of irreversible death, such as rigor mortis, decapitation, or decomposition, or if the scene is unsafe and presents a direct threat to the rescuer's life.

In a community setting, BLS can be performed with no equipment, though an Automated External Defibrillator (AED) should be sourced as soon as possible. In a clinical environment, equipment includes a firm flat surface (a cardiac board if on a hospital bed), a bag-valve-mask (BVM) connected to high-flow oxygen, and a pocket mask for rescue breaths. Personal protective equipment (PPE), including gloves, aprons, and eye protection, is essential in modern clinical practice following AGP (Aerosol Generating Procedure) guidelines.

Ensure the scene is safe and check for a response by shaking the shoulders and shouting. If no response, open the airway using head-tilt chin-lift (or jaw thrust if trauma is suspected) and check for breathing for up to 10 seconds. If not breathing, call emergency services and request an AED. Start 30 chest compressions at a rate of 100-120 bpm and a depth of 5-6 cm. After 30 compressions, deliver 2 rescue breaths (if trained and willing), each lasting 1 second. Continue this 30:2 cycle until an AED arrives, the patient recovers, or you are too exhausted to continue.

The effectiveness of BLS is interpreted by the presence of visible chest rise during rescue breaths and the maintenance of a consistent compression rate and depth. A rhythm check every 2 minutes (or when the AED prompts) determines the next steps (shockable vs. non-shockable). Clinical signs of success during the procedure include the patient regaining consciousness, moving, or breathing normally, which indicates Return of Spontaneous Circulation (ROSC). However, BLS must continue until a healthcare professional instructs otherwise or the patient clearly recovers.

A frequent error is failing to allow full chest recoil between compressions, which decreases venous return and reduces the efficacy of the next compression. Interruptions to compressions (e.g., for ventilation or rhythm checks) should be kept under 10 seconds, but students often take too long. Another common mistake is leaning on the patient's chest during the decompression phase. Inadequate depth (less than 5cm) or a rate that is too fast (over 120 bpm) also significantly reduces the chance of spontaneous circulation.

In an OSCE, always verbalise 'the scene is safe' before approaching the patient. When checking for breathing, look, listen, and feel for no more than 10 seconds while maintaining a head-tilt chin-lift. If you are alone, use your mobile phone on speaker to call 999/2222 while you start compressions. Don't forget to ask for an AED immediately. When performing compressions, lock your elbows and use your body weight to push straight down on the centre of the chest.

BLS is a 'Must-See' competency for the UK MLA. Candidates must follow the Resus Council UK (RCUK) algorithm precisely: Danger, Response, Shout for help, Airway, Breathing (DRSAB). In the AKT, expect questions on the ratio of compressions to breaths (30:2), the depth of compressions (5-6cm), and the rate (100-120bpm). Knowledge of the 'chain of survival' is also essential for theoretical assessment.