What is Basic Life Support (BLS)?

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From the Guidelines

Basic Life Support (BLS) is a critical emergency procedure that provides immediate care to individuals experiencing cardiac arrest or respiratory failure, and its core components include recognizing emergency situations, activating emergency response systems, performing high-quality chest compressions, providing rescue breaths, and using an automated external defibrillator (AED) when available, as outlined in the 2023 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations 1.

Key Components of BLS

The key components of BLS include:

  • Recognizing emergency situations and activating emergency response systems
  • Performing high-quality chest compressions at a rate of 100-120 compressions per minute, compressing the chest at least 2 inches (5-6 cm) deep for adults and 1.5 inches for infants
  • Providing rescue breaths, with a compression-ventilation ratio of 30:2 for adults and children
  • Using an automated external defibrillator (AED) when available

Importance of BLS

BLS is effective because immediate chest compressions help maintain blood flow to vital organs, particularly the brain, while rescue breaths provide oxygen until advanced medical care arrives. Early defibrillation with an AED is crucial for treating certain cardiac rhythms that cause sudden cardiac arrest. According to the 2023 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations, BLS can improve survival rates following witnessed out-of-hospital ventricular fibrillation (VF) arrest, with survival rates approaching 50% when implemented effectively 1.

Recent Guidelines

The 2023 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations provides the most recent and highest quality evidence for BLS, and its guidelines should be followed for optimal outcomes 1. The guidelines emphasize the importance of high-quality chest compressions, early defibrillation, and prompt activation of emergency response systems.

Implementation of BLS

Implementation of BLS should be based on the most recent and highest quality evidence, and healthcare providers should be trained in the latest guidelines and techniques. According to the 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, healthcare providers should continue effective chest compressions/CPR until return of spontaneous circulation (ROSC) or termination of resuscitative efforts 1.

From the Research

Definition of Basic Life Support (BLS)

  • Basic Life Support (BLS) is a method of sustaining vital functions in a person who has collapsed and is unconscious, frequently with a cardiac arrest but sometimes with respiratory arrest, choking or other cause 2.
  • BLS includes both prompt recognition and immediate support of ventilation and circulation in case of respiratory or cardiac arrest 3.
  • The major objective of BLS is to provide oxygen to the heart and the brain and to sustain tissue viability until definitive electrical or medical treatment can restore spontaneous circulation 3.

Components of BLS

  • BLS focuses on the primary survey A B C [D]: Airway [to open the airway]-Breath [to assess the presence or absence of spontaneous breathing and to provide ventilation]-Circulation [to assess pulselessness and to perform chest compression-Defibrillation 3.
  • BLS consists of provision of a patent upper airway, ventilation and circulation of blood by closed chest cardiac compressions 4.

Importance of BLS

  • Perfect, uninterrupted basic life support (BLS) is the key for successful cardiopulmonary resuscitation (CPR) in out-of-hospital cardiac arrest (OHCA) 5.
  • Promptly and optimally performed BLS is most effective and one major key to save life 3.
  • BLS is a vital link in the 'chain of survival' for critically ill people 2.

Future Directions for BLS

  • Future education research should develop more effective, simpler and quicker ways to enable everyone to acquire the necessary BLS skills 6.
  • Individualized self-training by lay persons is being revived, and airway control and direct mouth-to-mouth ventilation skills are difficult to acquire but must continue to be taught to the lay public and health professionals 6.
  • Novel laboratory research to remedy the limitation of low perfusion pressures produced by standard external CPR is important for the development of more effective emergency artificial circulation 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Resuscitation. 1: Basic life support.

British journal of hospital medicine, 1997

Research

[Basic Life Support: the primary ABC(D) of cardiopulmonary resuscitation].

Therapeutische Umschau. Revue therapeutique, 1996

Research

Current concepts in cardiopulmonary resuscitation in adults.

Journal of the Indian Medical Association, 1999

Research

[Resuscitation Update - What's New?].

Anasthesiologie, Intensivmedizin, Notfallmedizin, Schmerztherapie : AINS, 2024

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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