What are the key differences between Basic Life Support (BLS) and Advanced Cardiovascular Life Support (ACLS) in a cardiac arrest situation?

BLS and ACLS Overview

BLS (Basic Life Support) is the foundation of cardiac arrest management that anyone can perform, focusing on immediate chest compressions, rescue breathing, and early defibrillation with an AED, while ACLS (Advanced Cardiovascular Life Support) builds upon BLS by adding rhythm-specific protocols, advanced airway management, and pharmacologic interventions that require specialized training and equipment. 1

Basic Life Support (BLS)

Core Principles

• BLS can be performed by both lay rescuers and healthcare providers, with the primary objective of providing oxygen to the heart and brain until advanced treatment can restore spontaneous circulation 1, 2
• The American Heart Association changed the sequence from ABC to CAB to prioritize immediate chest compressions over airway positioning and rescue breaths 1
• Chest compressions are the foundation of CPR and should be the initial action for all victims regardless of age 3

Recognition and Activation

• Start CPR immediately if the adult victim is unresponsive and not breathing or not breathing normally (including only gasping) 3
• Activate the emergency response system immediately after recognizing cardiac arrest 3
• Do not waste time checking for pulse as pulse detection is often unreliable even by trained rescuers 3
• Agonal gasps are common early after sudden cardiac arrest and should not be confused with normal breathing 3

High-Quality Chest Compressions

• Compression depth: at least 2 inches (5 cm) for adults, approximately 2 inches (5 cm) in children, and at least one-third of the AP diameter (approximately 1½ inches or 4 cm) in infants 1, 3
• Compression rate: 100-120 compressions per minute 1, 4
• Allow complete chest recoil after each compression 1, 3
• Minimize interruptions in chest compressions, keeping pauses under 10 seconds 1, 4
• Push hard and push fast without excessive interruptions 4

Compression-to-Ventilation Ratios

• Single rescuer (all ages except newborns): 30 compressions to 2 breaths 3, 1
• Two healthcare provider rescuers (pediatric): 15 compressions to 2 breaths 1
• Each rescue breath should be delivered over 1 second with sufficient volume to achieve visible chest rise 3

Defibrillation

• Apply AED pads as soon as available, ideally without interrupting chest compressions 3
• Follow AED prompts to either deliver a shock or continue CPR 3
• Hands-only CPR is encouraged for untrained lay rescuers, as it is easier to perform and can be guided by dispatchers over the telephone 1

Advanced Cardiovascular Life Support (ACLS)

Team-Based Approach

• ACLS requires a simultaneous, choreographed approach by an integrated team, with multiple tasks performed concurrently by different team members 1, 3
• While one rescuer performs chest compressions and another performs ventilations, other rescuers should obtain a monitor/defibrillator, establish vascular access, and prepare medications 3
• Start chest compressions immediately by one rescuer, while a second rescuer prepares to start ventilations with a bag and mask 3

Rhythm-Based Management

Shockable Rhythms (VF/Pulseless VT)

• Deliver one shock immediately as soon as the defibrillator is available 1, 4
• Use 120-200J for biphasic defibrillators or 360J for monophasic defibrillators 1, 4
• Resume CPR immediately after shock for 2 minutes before rhythm reassessment 1, 4
• Administer epinephrine 1mg IV/IO every 3-5 minutes 1, 4
• For refractory VF/pVT (after 2-3 shocks), consider antiarrhythmic drugs such as Amiodarone or Lidocaine 4
• Victims who present with VF or pulseless VT have substantially better outcomes compared with those who present with asystole or pulseless electrical activity 3

Non-Shockable Rhythms (Asystole/PEA)

• Continue high-quality CPR 1
• Administer epinephrine 1mg IV/IO every 3-5 minutes 1, 4
• Consider and treat reversible causes (the H's and T's) 1

Advanced Airway Management

• Consider advanced airway placement (endotracheal tube or supraglottic airway) without interrupting chest compressions 1, 4
• Either supraglottic airway or endotracheal tube can be used in the in-hospital setting by expert providers trained in these procedures 3
• Confirm proper placement with waveform capnography 1, 4
• After advanced airway placement, deliver 1 breath every 6 seconds (10 breaths/min) with continuous chest compressions 1, 4
• Frequent experience or frequent retraining is recommended for providers who perform endotracheal intubation 3

Monitoring During Resuscitation

• Use quantitative waveform capnography to confirm and monitor advanced airway placement 4
• Monitor CPR quality with target PETCO₂ >10 mmHg 4
• ETCO₂ should not be used alone as a mortality predictor or to terminate resuscitation 4

Pharmacologic Therapy

• Epinephrine is the cornerstone of ACLS pharmacotherapy, administered at 1mg IV/IO every 3-5 minutes 3, 1, 4
• Antiarrhythmic drugs (Amiodarone or Lidocaine) are considered for refractory VF/pVT 4
• Drugs can be administered via endotracheal tube (epinephrine, lidocaine, atropine) if intravenous access has not been established 5

Key Differences Between BLS and ACLS

Scope of Practice

• BLS focuses on recognition, chest compressions, rescue breathing, and AED use 1, 2
• ACLS adds rhythm interpretation, manual defibrillation, advanced airways, IV/IO access, and medications 1, 5

Equipment Requirements

• BLS requires minimal equipment: hands for compressions, barrier device for breaths, and an AED 1
• ACLS requires specialized equipment: cardiac monitor/defibrillator, advanced airway devices, IV/IO supplies, and emergency medications 1, 5

Training Level

• BLS can be performed by lay rescuers with basic training 1, 2
• ACLS requires healthcare providers with advanced training in rhythm recognition, pharmacology, and advanced procedures 1, 5

Decision-Making

• BLS follows a simple algorithm: compressions, breaths, and AED prompts 1
• ACLS requires complex decision-making based on cardiac rhythm, patient response, and reversible causes 1, 4

Special Considerations

Pediatric Differences

• Cardiac arrest in children is most often asphyxial, requiring both ventilations and chest compressions for optimal results 3
• Rescue breathing may be more important for children than for adults in cardiac arrest 3
• Ventilation is extremely important in pediatrics because of the large percentage of asphyxial arrests 3

Pregnant Patients

• Perform continuous manual left uterine displacement to relieve aortocaval compression during resuscitation if the uterus is at or above the umbilicus 3, 4
• Hand placement for chest compressions remains the same as in non-pregnant patients 3

Post-Resuscitation Care

• Maintain oxygenation and ventilation, avoiding both hypoxia and hyperoxia 4
• Maintain hemodynamic stability 4
• Consider emergent coronary angiography for patients with ST-segment elevation on ECG or signs of ongoing myocardial damage 4

Common Pitfalls to Avoid

• Do not delay chest compressions to establish an airway or obtain vascular access 3
• Do not interrupt compressions for prolonged periods during rhythm checks or defibrillation preparation 1, 4
• Do not hyperventilate patients, as this decreases venous return and cardiac output 3
• Do not rely solely on pulse checks for cardiac arrest recognition, as they are unreliable 3
• Do not use excessive tilt in pregnant patients, as manual left uterine displacement is more effective 3