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Introduction
Basic Life Support (BLS) refers to a level of emergency care used for life-threatening situations such as cardiac arrest or respiratory failure before advanced medical help is available. It involves a set of life-saving interventions that can be administered by trained healthcare professionals as well as untrained laypersons to help maintain circulation and ventilation until the arrival of more definitive medical treatment [1].
The American Heart Association (AHA) periodically updates its guidelines for BLS based on a continuous review of current research. These guidelines outline important changes to the sequence of BLS care, medication administration, education methods, and other updates to improve outcomes for patients in critical situations [1]. The most recent AHA guidelines, published in 2020, provide a step-by-step approach for managing adults who experience cardiac arrest or other life-threatening emergencies outside of a hospital setting [1].
Initial Assessment and Activation of Emergency Response
The first steps when coming upon an unresponsive or critically ill person involve quickly checking the scene for safety, determining the patient’s level of consciousness by tapping their shoulders and shouting, and checking for breathing and a pulse [1]. Agonal gasps should not be mistaken for normal breathing. If the patient does not have a definite pulse within 10 seconds, the rescuer should presume the patient is in cardiac arrest and immediately activate the emergency response system [1].
Starting CPR
Once cardiac arrest is recognized, chest compressions should be started promptly at a rate of 100-120 compressions per minute with a compression depth of 2-2.4 inches [1]. The chest should be allowed to fully recoil after each compression to allow for venous return to the heart [1]. Compressions should be accompanied by rescue breaths in a 30:2 ratio (30 compressions to 2 breaths) for patients who are not intubated. Rescue breaths should be 1 second long and result in visible chest rise [1].
For patients who have a pulse but are not breathing adequately, rescue breathing alone is initiated [1]. In all cases, CPR should continue until the patient starts breathing effectively on their own, an automated external defibrillator (AED) becomes available, or EMS providers take over care [1].
Compression-Only CPR
The AHA guidelines state that untrained lay rescuers who have not received CPR training or are uncomfortable giving rescue breaths may provide compression-only CPR [1]. This involves continuous chest compressions at a rate of 100-120 per minute without any ventilations [1]. Compression-only CPR has been shown to save lives compared to no CPR when performed by untrained laypersons for patients whose cardiac arrest was not caused by a respiratory etiology [2-4]. However, conventional CPR with compressions and ventilations in a 30:2 ratio is preferred when trained rescuers are present.
CPR Quality
It is critical that chest compressions are performed at an adequate depth and rate with full chest recoil after each compression [1]. Use of quantitative waveform capnography during CPR can provide feedback on compression quality, as end-tidal CO2 (EtCO2) levels correlate with cardiac output [1]. EtCO2 levels above 10 mmHg suggest the compressions are providing adequate blood flow, while levels below 10 mmHg indicate suboptimal CPR quality [5].
The updated AHA guidelines recommend designating a CPR coach during in-hospital cardiac arrest response [1]. The coach helps minimize pauses during CPR by coordinating compressor changes, defibrillation, and airway management. They also monitor CPR quality and provide instructions to improve the rate and depth of compressions [1].
The guidelines also emphasize the importance of a debriefing after the cardiac arrest emergency to discuss resuscitation efforts and identify areas for future improvement [1].
Defibrillation
Automated external defibrillators (AEDs) enable early defibrillation to terminate ventricular fibrillation and pulseless ventricular tachycardia, which are rhythm disturbances associated with cardiac arrest [1]. Using an AED as soon as possible after recognizing cardiac arrest is critical to patient survival. Steps include turning on the AED, attaching the electrode pads to the patient’s bare chest, and following the voice prompts [1]. CPR should be resumed immediately after the AED delivers a shock or advises that no shock is needed.
Conclusion
In conclusion, BLS plays a vital role in emergency care as the first line of defense for life-threatening situations before advanced medical intervention arrives. Up-to-date knowledge and skills in BLS are essential both for healthcare professionals and untrained bystanders to perform interventions that can save lives. The AHA BLS guidelines provide a structured approach to recognizing cardiac arrest, activating EMS, initiating high-quality CPR, and utilizing AEDs. Adhering to the latest guidelines optimizes outcomes for critically ill patients requiring timely BLS care.
References:
- Panchal AR, Bartos JA, Cabañas JG, et al. Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2020;142:S366-S468.
- Svensson L, Bohm K, Castrèn M, et al. Compression-only CPR or standard CPR in out-of-hospital cardiac arrest. N Engl J Med. 2010;363:434-442.
- Rea TD, Fahrenbruch C, Culley L, et al. CPR with chest compression alone or with rescue breathing. N Engl J Med. 2010;363:423-433.
- SOS-KANTO Study Group. Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study. Lancet. 2007;369:920-926.
- Paiva EF, Paxton JH, O’Neil BJ. The use of end-tidal carbon dioxide (ETCO2) measurement to guide management of cardiac arrest: A systematic review. Resuscitation. 2018;123:1-7.