AHA BLS Initial

Basic Life Support For Healthcare Providers (BLS) Initial Certification Course is a set of emergency procedures by the American Heart Association. This course teaches doctors, first responders, nurses, medical personnel, and public safety professionals, paramedics and prehospital providers how to perform high quality CPR on an adult, child and infant and how to use a pocket mask, bag valve mask and an AED. This course also teaching how to help choking victims. 

These guidelines are used to help people who are experiencing cardiac arrest, respiratory distress, or an obstructed airway. Basic life support is a level of medical care which is used for patients with life-threatening condition of cardiac arrest until they can be given full medical care by advanced life support providers.

BLS training reinforces healthcare professionals’ understanding of the importance of early CPR and defibrillation, performing CPR, choking relief, using an AED, and the role of each link in the Chain of Survival. BLS is performed to support the patient's circulation and respiration through the use of cardiopulmonary resuscitation (CPR).

In this course you will learn:

• High-quality BLS for adults, children, and infants

• Use of an AED

• Effective ventilation using a barrier device

• Relief of foreign-body airway obstruction for adults, children, and infants

• High-performance teams

CPR Coach

The CPR Coach is a new role within the resuscitation team. The CPR Coach role is designed to promote the delivery of high-quality CPR and allow the Team Leader to focus on other elements of cardiac arrest care, coordinate the various team members’ assigned tasks, and ensure that clinical care is delivered according to AHA guidelines.

The AHA has adopted an open-resource policy for exams. Open resource means that students may use resources as a reference while completing the exam. Resources could include the provider manual, either in printed form or as an eBook on personal devices, any notes the student took during the provider course, the 2025 Handbook of ECC for Healthcare Providers, the AHA Guidelines for CPR and ECC, posters, etc. Open resource does not mean open discussion with other students or the Instructor. Students may not interact with each other during the exam.

To successfully complete this course and receive your BLS course completion card, students must do

the following:

• Participate in hands-on interactive demonstrations of high-quality CPR skills

• Pass the Adult CPR and AED Skills Test

• Pass the Infant CPR Skills Test

• Score at least 84% on the exam

Upon completion of the course, students will receive an American Heart Association BLS Provider Card valid for two years. Once you receive your card, be sure to set an alarm on your phone for 23 months from now. That way you’ll have 30 days to find and attend a class before your expiration date. Your card is good until midnight on the last day of the month.

Continuing Education Accreditation – Emergency Medical Services This continuing education activity is approved by the American Heart Association, an organization accredited by the Commission on Accreditation of Pre-Hospital Continuing Education (CAPCE), for 3.25 Educator CEHs, activity number 20-AMHA-F2-0083.

The American Heart Association’s 2025 Adult Basic Life Support Guidelines

The American Heart Association’s 2025 Adult Basic Life Support Guidelines build upon prior versions with updated recommendations for assessment and management of persons with cardiac arrest, as well as respiratory arrest and foreign-body airway obstruction. The chapter addresses the important elements of adult basic life support including initial recognition of cardiac arrest, activation of emergency response, provision of high-quality cardiopulmonary resuscitation, and use of an automated external defibrillator. In addition, there are updated recommendations on the treatment of foreign-body airway obstruction. The use of opioid antagonists (eg, naloxone) during respiratory or cardiac arrest is incorporated into the adult basic life support algorithms, with more detailed information provided in “Part 10: Adult and Pediatric Special Circumstances of Resuscitation.”

 

 

Top 10 Take-Home Messages

  1. In adult cardiac arrest, resuscitation should generally be conducted where the patient is found, as long as high-quality cardiopulmonary resuscitation (CPR) can be administered safely and effectively.
  2. After identifying an adult in cardiac arrest, a lone responder should activate the emergency response system first, then immediately begin CPR.
  3. In adult cardiac arrest, rescuers should perform chest compressions with the patient’s torso at approximately the level of the rescuer’s knees.
  4. It is reasonable for health care professionals to perform chest compressions and ventilations for all adult patients in cardiac arrest from either a cardiac or noncardiac cause.
  5. When ventilating adult patients in cardiac arrest, it is reasonable to give enough tidal volume to produce visible chest rise while avoiding hypo- and hyperventilation.
  6. The routine use of mechanical CPR devices is not recommended for adults in cardiac arrest.
  7. For adult patients who are not breathing normally but have a pulse, it is reasonable for rescuers to provide 1 breath every 6 seconds (10 breaths per minute).
  8. CPR for adult cardiac arrest patients with obesity should be provided by using the same techniques as for the average weight patient.
  9. For adults with severe foreign-body airway obstruction (FBAO), rescuers should perform cycles of 5 back blows followed by 5 abdominal thrusts until the object is expelled or the patient becomes unresponsive.
  10. During adult cardiac arrest, it is reasonable for rescuers to use personal protective equipment (PPE) while performing CPR.

Preamble

The annual incidence of adults treated by emergency medical services (EMS) for out-of-hospital cardiac arrest (OHCA) in the United States varies considerably between states, but is estimated at 356 000, or 83 per 100 000 populations.1,2 Despite advances in public education and awareness, as well as improvement in community-based systems of care, survival for adults after OHCA remains low and decreased during the COVID-19 pandemic.3 The Cardiac Arrest Registry to Enhance Survival (CARES) is a voluntary OHCA database used by EMS agencies and hospitals to generate Utstein-style reports and to benchmark performance and outcomes against similar systems. Developed in 2004, CARES now has participating sites from 37 states covering approximately 56% of the US population. CARES OHCA data from 2024 showed that survival to hospital discharge was 10.5%, with favorable neurologic outcome reported in approximately 8.2%.4 The majority of adult OHCA occurred in private residences while 18% occurred in public places. Bystander CPR was provided in 47.7% of adult OHCA, and a bystander used an automated external defibrillator (AED) in 7.9% of cases. There is significant variation in rates of bystander CPR, public AED use, EMS response times, and survival from cardiac arrest between geographic regions, as well as disparities associated with race, sex, and socioeconomic status.5,6

The annual incidence of adult in-hospital cardiac arrest (IHCA) in the United States is estimated to be 292 000 by extrapolation from the Get With The Guidelines-Resuscitation registry.7 Approximately 60% of adult IHCA occur in an acute care setting (eg, intensive care unit, emergency department, operating room) while 40% occur on the general inpatient units. Survival to hospital discharge decreased from 26.7% to a low of 18.8% during the COVID-19 pandemic, with improvement to 23.6% in 2023.1 Racial and sex-related outcome disparities have also been observed in the IHCA setting.8,9

Early, high-quality CPR and prompt defibrillation are the most important interventions associated with improved outcomes in adult cardiac arrest. Despite this, a 2015 US prevalence report found that only 18% of people surveyed had current CPR training,10 with lower rates in under-represented and low-income populations. More lives could be saved if a greater proportion of the public was trained in, and willing to perform, basic life support, especially chest compressions.11

Since 2010, the American Heart Association (AHA) Emergency Cardiovascular Care (ECC) Committee has regularly set goals aimed at increasing survival from cardiac arrest. The accompanying strategies focus on strengthening the links in the Chain of Survival to prevent, identify, treat, and support all phases of care for persons who are at risk for, or experience, cardiac arrest. The fundamental basic life support tasks of recognition of cardiac arrest, activation of emergency response, performance of chest compressions and ventilations, and use of an AED for defibrillation are critical components representing the first links of the Chain of Survival that must be optimized so persons with cardiac arrest can fully benefit from advanced cardiovascular care therapies.12

The 2030 Impact Goals focus on improving survival to hospital discharge with favorable neurologic outcome for individuals experiencing OHCA or IHCA.13 Not surprisingly, the first 2 goals are related to basic life support: bystander CPR and public access defibrillation. Specifically, the first goal calls for an increase in bystander adult CPR performance rates to greater than 50%, while the second goal is to increase the proportion of adults with cardiac arrest for whom an AED is applied before emergency medical response arrival to greater than 20%. To accomplish these goals, the evidence-based recommendations for performance of high-quality basic life support provided in this chapter must be coupled with strategies for awareness, advocacy, and education that improve the system of care for all persons. The accompanying chapters “Part 12: Resuscitation Education Science” and “Part 4: Systems of Care”  provide recommendations for optimizing the community and health care system approach to cardiac arrest treatment, including bystander CPR training, telecommunicator CPR, public access defibrillation, and timely activation of the emergency medical response system. While all components of the Chain of Survival are essential, high-quality basic life support is foundational to improving outcomes.

 

Introduction

These recommendations supersede the last full set of AHA Guidelines for Adult Basic Life Support published in 202014 unless otherwise specified. The writing group reviewed all relevant and current AHA Guidelines for CPR and ECC and all relevant International Liaison Committee on Resuscitation (ILCOR) consensus on CPR and ECC science with treatment recommendations from 2020 through 2024.15-18 Evidence and recommendations were reviewed to determine if current guidelines should be reaffirmed, revised, or retired, or if new recommendations were needed. The writing group then drafted, reviewed, and approved each recommendation. For topics that did not undergo full evidence review or updated literature search, the recommendations, recommendation-specific supportive text, and references from the 2020 Basic Life Support Guidelines were not updated and were carried over. These topics are noted within the synopsis of their respective sections and remain as the current guidelines for 2025.

 

Scope of the Guidelines

The 2025 Adult Basic Life Support Guidelines apply to a range of responders, including trained and untrained lay rescuers and health care professionals, with the understanding that systems of prehospital and in-hospital care vary widely across the world. They address the treatment of cardiac arrest as well as other immediately life-threatening conditions including respiratory arrest and FBAO. A person in cardiac arrest who has signs of puberty is treated by using the Adult Basic Life Support Guidelines; guidelines for pediatric patients are discussed in “Part 6: Pediatric Basic Life Support.”

 

Updated AHA Algorithms for Adult Basic Life Support and Foreign-Body Airway Obstruction

Three algorithms are included in the 2025 Guidelines as resources. The Adult Basic Life Support for Health Care Professionals Algorithm (Figure 1) now incorporates the use of opioid antagonists for both respiratory and cardiac arrest. A new adult basic life support algorithm (Figure 2) illustrates the approach for lay rescuers. A new algorithm for assessment and treatment of FBAO (Figure 3) is also provided.

 Figure 2. Adult Basic Life Support Algorithm for Lay Rescuers.
AED indicates automated external defibrillator; CPR, cardiopulmonary resuscitation.
 
Figure 3. Adult Foreign-Body Airway Obstruction Algorithm
 
Figure 3. Adult Foreign-Body Airway Obstruction Algorithm.
BLS indicates basic life support; CPR, cardiopulmonary resuscitation; and FBAO, foreign-body airway obstruction.
 
 

Recognition of cardiac arrest can be difficult, especially in the out-of-hospital setting.1 Accurate detection of a pulse is challenging for all levels of responders, increasing the risk for delays in initiation of chest compressions and activation of emergency medical response. Recognition by lay rescuers is, therefore, based primarily on level of consciousness and respiratory effort rather than using a pulse check. Health care professionals are encouraged to check for a pulse as one component of the recognition of cardiac arrest; however, the emphasis is on prompt initiation of CPR if a pulse is not definitively felt.

Recommendation-Specific Supportive Text

  1. Assessment of patient unresponsiveness and absent or abnormal breathing have been shown to rapidly identify a significant proportion of patients who are in cardiac arrest.2 Agonal breathing is characterized by slow, irregular gasping respirations that are ineffective for ventilation. Agonal breathing is described by lay rescuers with a variety of terms including abnormal breathing, snoring respirations, and gasping.3 Agonal breathing is common, reported as being present in up to 40% to 60% of OHCA, and diminishes the longer a person is in cardiac arrest.4,5 The presence of agonal breathing is cited as a common reason for lay rescuers to misdiagnose a patient as not being in cardiac arrest,6 and may lead to delays in initiation of chest compressions. Furthermore, the risk of harm associated with providing chest compressions to an unconscious patient who is not in cardiac arrest is low.7-11 The benefit of providing CPR for someone in cardiac arrest far outweighs any risk associated with providing chest compressions to someone who is not.
  2. Protracted delays in CPR can occur when checking for a pulse at the outset of resuscitation efforts as well as between successive cycles of CPR. Health care professionals often take too long to check for a pulse and have difficulty determining if a pulse is present or absent.12-14 There is no evidence, however, that checking for breathing, coughing, or movement is superior to a pulse check for detection of circulation.15 Thus, health care professionals are directed to quickly check for a pulse and to promptly start compressions when a pulse is not definitively palpated within 10 seconds.

 

The first link in the Chain of Survival for cardiac arrest includes prompt activation of the emergency response system. Given that most lay rescuers will likely have mobile phones with hands-free options, it is possible for lay rescuers to provide CPR and activate the emergency response system at nearly the same time. Alternatively, a second lay rescuer can be instructed to call 911. Activation of the emergency response system allows for provision of telecommunicator CPR, possible notification of other lay rescuers via crowd-sourced applications, and dispatch of the designated EMS agency.

Immediate chest compressions are critical to improve patient outcomes from OHCA, and a chest compression–only approach is appropriate if lay rescuers are untrained or unwilling to provide breaths. Because CPR with breaths may lead to improved outcomes for adults in comparison with chest compression–only CPR, trained rescuers are encouraged to provide breaths along with chest compressions. PPE provides an important barrier against certain infectious diseases, but lay responders may have limited access to PPE.

Recommendation-Specific Supportive Text

  1. Immediate initiation of chest compressions is one of the most impactful interventions for survival from cardiac arrest.1-3 In Japan, nationwide dissemination of chest compression–only CPR for lay rescuers was associated with an increase in the incidence of survival with favorable neurological outcome after OHCAs, likely due to an increase in lay rescuers providing CPR.4 Providing manual chest compressions for an unconscious patient not in cardiac arrest has not been associated with serious harm, as demonstrated in several observational studies.5-10 The risk-to-benefit ratio remains heavily in favor of initiating CPR for presumed cardiac arrest when compared to the significant harm of withholding CPR when a patient is in cardiac arrest.
  2. A previous large observational study (N=17 461)) found no difference in survival to hospital discharge between patients receiving CPR before a call and patients receiving CPR after a call to the emergency response system.7,11 Our recommendation values the practical considerations of timely emergency medical response dispatch and the availability and value of remote assistance to improve the quality of CPR.
  3. Use of the “hands-free” speaker feature on most cell phones, when and where available, can help with near-simultaneous activation of emergency response and initiation of CPR. In situations where a phone is not immediately available, local circumstances will determine decisions about delaying CPR to activate the emergency medical response system; however, the importance of timely CPR must be emphasized.
  4. Numerous observational studies and 1 large secondary analysis of an RCT found improved outcomes in patients with cardiac arrest who received both chest compressions and ventilations compared with those who received chest compressions only.4,12-14 Other observational studies have reported no difference in outcome for patients receiving compressions and ventilations compared with compression-only CPR.13,15-21 Given the potential benefit of including both compressions and ventilations during CPR, if lay rescuers are appropriately trained, they should be encouraged to deliver breaths with compressions.
  5. The impact of PPE on CPR performance is an important consideration for responders. Although transmission of disease during CPR is uncommon, the COVID-19 pandemic heightened awareness of the importance of protection of rescuers, especially from airborne pathogens such as respiratory viruses. Because CPR is considered an aerosol-generating procedure, the use of PPE has become the norm. Safety and protection of the rescuer are of utmost importance in responding to cardiac arrest. Rescuers must be aware, however, that the process of donning PPE may delay the initiation of CPR, and use of PPE has the potential to adversely affect CPR performance and increase rescuer fatigue.22 A 2023 systematic review and meta-analysis found no difference in survival (1 clinical study)23 nor any change in CPR performance (17 manikin studies), with donning of PPE in simulated cardiac arrest.24 Two pooled studies from the same meta-analysis showed worse fatigue scores when rescuers performed CPR while wearing PPE.25,26 More information is provided in “Part 10: Adult and Pediatric Special Circumstances of Resuscitation.”

As health care professionals are trained to deliver compressions and ventilation, they are in a position to provide both during adult basic life support.

  1. The circulation, airway, and breathing approach for adults is supported by a 2024 ILCOR systematic review.1-3,7,28 Once chest compressions have been started, a single trained rescuer delivers breaths by mouth-to-mask or by bag-mask device to provide oxygenation and ventilation. Manikin studies demonstrate that starting with chest compressions rather than with ventilation is associated with faster times to chest compressions, breaths, and completion of the first CPR cycle.2,3,29
  2. Numerous studies have shown improved outcomes when ventilations are provided in addition to chest compressions for adults in cardiac arrest.4,12-14 Delivery of chest compressions without assisted ventilation for prolonged periods could be less effective than conventional CPR (compressions plus ventilation) because arterial oxygen content decreases as CPR duration increases. This concern is especially pertinent in the setting of asphyxial cardiac arrest.13 Health care professionals, with their training and understanding, can realistically tailor the sequence of subsequent rescue actions to the most likely cause of arrest.

Opening the airway is a key component of basic life support for patients who are unresponsive with or without respiratory or cardiac arrest. Unresponsive individuals are at risk for airway obstruction primarily due to the tongue falling to the back of the oropharynx as the oropharyngeal muscles lose tone. Untreated airway obstruction can lead to hypoxia and hypercarbia, which may precipitate cardiac arrest. Alternatively, uncorrected airway obstruction may hinder resuscitation efforts. Airway adjuncts such as oropharyngeal and nasopharyngeal airways can improve airway patency by creating a passage between the tongue and the pharynx. However, these devices have contraindications with suspected facial trauma (nasopharyngeal airway) and an intact gag reflex (oropharyngeal airway). Rescuers need to consider the possibility of cervical spine injury when there is known or suspected trauma. Cricoid pressure has not been shown to have benefit and has the potential to interfere with air entry into the trachea during bag-mask ventilation.

Recommendation-Specific Supportive Text

  1. The head tilt–chin lift is an effective technique to open an airway as demonstrated in noncardiac arrest and radiological studies (Figure 4).1-4 No studies have compared head tilt–chin lift with other airway maneuvers to establish an airway during cardiac arrest.
 
  1. The benefit of an oropharyngeal airway compared with a nasopharyngeal airway in the presence of a known or suspected basilar skull fracture or severe coagulopathy has not been assessed in clinical trials. However, use of an oropharyngeal airway reduces the risk of intracranial passage that may occur with nasopharyngeal airway insertion. Two case reports observed intracranial placement of nasopharyngeal airways in patients with basilar skull fractures.5,6
  2. Oropharyngeal and nasopharyngeal airway adjuncts can be used to maintain a patent airway and facilitate appropriate ventilation by preventing the tongue from occluding the airway. Incorrect placement, however, can cause an airway obstruction by displacing the tongue to the back of the oropharynx.1-4,7,8 One retrospective study reported improved neurologic outcomes during IHCA with use of airway adjuncts (eg, oropharyngeal or nasopharyngeal airway) in combination with bag-mask ventilation.9
  3. There is no evidence that cricoid pressure facilitates ventilation or reduces the risk of aspiration in cardiac arrest patients.10 There is some evidence that in non–cardiac arrest patients, cricoid pressure may protect against aspiration and gastric insufflation during bag-mask ventilation.11-14 However, additional studies, including a recent systematic review, found that cricoid pressure failed to reduce aspiration and may impede the placement of an advanced airway.15-19

An adult with signs of head or neck trauma may have a cervical spine injury. Trained rescuers should attempt to open the airway using the jaw thrust technique because this maneuver produces less movement of the head and neck than a head tilt–chin lift.  If it is not possible to achieve an open airway with a jaw thrust and insertion of an airway adjunct, trained rescuers should open the airway by using the head tilt–chin lift given the critical importance of oxygenation and ventilation. No new evidence was identified on this topic during the 2025 evidence review.

  1. If an unresponsive person has head or neck trauma, there is a possibility of cervical spinal injury. Trained rescuers should open the airway by using a jaw thrust instead of head tilt–chin lift.1
  2. Maintaining a patent airway and providing adequate ventilation and oxygenation are priorities during CPR. If a jaw thrust and insertion of an airway adjunct are ineffective, a head tilt–chin lift may be necessary to open the airway. The importance of a patent airway outweighs the risk of further spinal damage in the cardiac arrest patient even in the setting of head and neck trauma.
  3. Manual spinal motion restriction can decrease movement of the cervical spine during patient care while allowing for proper ventilation and airway control.20,21 When head and neck injury are present, lay rescuers should maintain manual spinal motion restriction and should not use rigid cervical collar devices. Spinal immobilization devices such as rigid cervical collars may make it more difficult to maintain airway patency22,23 and provide adequate ventilation. 

High-quality resuscitation is vital for improved cardiac arrest outcomes including return of spontaneous circulation (ROSC) and survival. The effectiveness of chest compression delivery can be improved through optimizing rescuer hand position, rescuer body position, and patient position.

Figure 6. Side view of rescuer position and hand location for chest compressions

 

  1. Rescuer position in relationship to the patient can affect chest compression quality. Multiple simulated cross-over RCTs have shown that kneeling on the floor or in the bed next to the manikin resulted in improved chest compression depth compared to standing in adult populations.1-6 Straddling the patient to perform CPR is similar to kneeling with improved chest compression quality in comparison to standing or walking alongside the patient while performing CPR on a moving cot7,8,9 However, kneeling and straddling, especially on a moving cot, needs to be weighed against rescuer safety and stability. One moderate-sized (n=124) RCT did not find benefit with straddling CPR compared to conventional lateral CPR while performed in a confined space.10 Two studies specifically evaluating height found that when the manikin torso was no more than 10 cm below the rescuer’s knee this was associated with improved chest compression depth.11,12 Using a step stool for rescuer elevation has also shown to improve chest compression quality in comparison to standing.1,4 Two RCTs demonstrated slightly higher chest compression quality metrics including depth and recoil with kneeling compared to step stool use.1,4
  2. A 2020 ILCOR systematic review identified 3 studies involving 57 patients that investigated the effect of hand positioning on resuscitation process and outcomes.13 No new studies were identified in a recent update of this review. Although no differences in resuscitation outcomes were noted, 2 studies found better physiological parameters (peak arterial pressure, mean arterial pressure, and end-tidal carbon dioxide) when compressions were performed over the lower third of the sternum compared with the middle of the sternum.14,15 A third study found no difference.16 Radiographic studies show the left ventricle is typically located inferior to the inter nipple line, corresponding with the lower half of the sternum.17 However, hand placement inferior to the inter nipple line may result in compression over the xiphoid, which may be less effective.18
  3. The ability to safely provide high-quality CPR should remain the highest priority when considering if a patient needs to be moved before initiation of CPR. If adequate chest compressions can be effectively provided while maintaining rescuer safety in the location the patient is found, immediate resuscitation can occur at this location. Importantly, delay in initiation of chest compressions is associated with worse outcomes. In a study of telephone-assisted CPR during OHCA, delays to CPR due to patient repositioning occurred in 41% of cases, most commonly due to physical limitations of the rescuer. Odds of survival to hospital discharge was significantly lower in the group with delayed chest compressions.19 This recommendation is not intended to apply to decision-making for the timing of transportation from the scene when a patient remains in cardiac arrest.
  4. A firm surface improves the likelihood of adequate chest compression depth. A recent systematic review including manikin studies recommended the use of a backboard in hospital settings to provide a firm surface for CPR.20 Similarly, compressions on a deflated dynamic mattress or use of bed manufacturer “CPR mode” in-hospital can improve chest compression depth.21,22 Studies have supported that optimal chest compressions are best delivered with the person on a firm surface such as the floor.23,24
  5. Dominant hand placement on the sternum may provide improved chest compression quality. One moderate-sized (n=101) RCT and 1 (n=225) observational study showed improved chest compression quality with dominant hand placement against the sternum.25-27 Another smaller RCT (n=59) found a non-significant improvement with dominant hand placement on the sternum.28
  6. While it is preferred to perform chest compressions with the patient in the supine position, there are circumstances in which the patient is in the prone position at the time of cardiac arrest. There are multiple case reports of performing resuscitation in the prone position for patients who experience cardiac arrest during operative procedures or while in the prone position for treatment of COVID-19–associated respiratory failure.29-31 A 2021 systematic review by ILCOR reported 20 adult patients with cardiac arrest in the prone position in the operating room or intensive care unit. Of the 12 patients who received CPR in the prone position, all experienced ROSC and survival to discharge. Of the 8 patients who were supinated before initiation of CPR, the rate of ROSC and survival to discharge were 37.5% and 29%, respectively.32
 High-quality CPR is one of the most important interventions to improve survival from cardiac arrest. One key feature of high-quality CPR is to minimize interruptions in chest compressions, in addition to providing chest compressions of adequate rate and depth, allowing full chest recoil between compressions, and avoiding excessive ventilations.33,34 Chest compressions are required for forward flow during cardiac arrest and pauses in chest compressions have been shown to result in an almost immediate drop in coronary perfusion pressure, which is associated with reduced likelihood of ROSC.35,36 While some pauses in chest compressions, such as for ventilations and pulse checks, are necessary, ensuring that the number and duration of pauses are kept to a minimum is critical. The chest compression fraction (CCF) refers to the proportion of time a patient is receiving chest compressions during a resuscitation.
  1. An increase in the overall hands-on time (CCF) during resuscitation is directly associated with improved survival from cardiac arrest.37-39 Observational studies suggest improved outcomes with increased CCF in patients with shockable rhythms,40,41 as well as an association between ROSC and shorter perishock pauses.37,42-44
  2. Pulse checks and rhythm checks are common reasons for pauses in chest compressions that can reduce the CCF.45 Patient, environmental, and logistical factors can make pulse checks difficult to perform. Observational studies have shown that pulse checks can be prolonged greater than 10 seconds, further reducing the CCF.46
  3. Immediate resumption of chest compressions after a shock results in a shorter perishock pause and improves the overall hands-on time (CCF) during resuscitation. Two RCTs enrolling more than 1000 patients did not find any increase in survival when pausing CPR to analyze rhythm after defibrillation.47,48 Observational studies showed decreased ROSC when chest compressions are not resumed immediately after shock.38,49
  4. Chest compression depth begins to decrease after 90 to 120 seconds of CPR, although compression rates do not decrease significantly over that time window.50 A randomized trial using manikins found no difference in the percentage of high-quality compressions when rotating every 1 minute compared with every 2 minutes.51 Rotating the designated chest compressor every 2 minutes is sensible because this approach maintains chest compression quality and takes advantage of when CPR would ordinarily be paused for rhythm analysis.
  5. Keeping pauses for ventilations as short as possible helps to maintain high CCF and improve resuscitation outcomes.40,41,52 However, there is new evidence that ventilations delivered during the pause when using a 30:2 compression-to-ventilation ratio are often ineffective. In an analysis of the Resuscitation Outcomes Consortium data, investigators found that effective ventilations were delivered during fewer than half of the pauses. Importantly, when compared to the group for whom effective ventilations were provided more than 50% of the time, patients with a lower proportion of effective ventilations had worse rates of ROSC, survival to hospital discharge, and survival with favorable neurologic outcome.53
  6. Minimizing interruptions in CPR and maintaining a CCF of at least 60% has been associated with improved outcomes in a number of observational studies.39,40,52 A 2015 systematic review reported significant heterogeneity among studies, with some studies, but not all, reporting better rates of survival to hospital discharge associated with higher CCF.40,41,52 In 2 studies, higher CCF was associated with lower odds of survival.54,55 A 2020 retrospective review of the Resuscitation Outcomes Consortium found an association between higher CCF and ROSC, but not survival, among patients with a nonshockable rhythm and a CCF of at least 40%.39 Compression rate and depth and associated interventions such as defibrillation, airway management, and medications, are also important and may interact with CCF. While a CCF of 60% is considered a minimum target, high performance teams may achieve higher levels (eg: greater than 80%).
  7. Interruptions to CPR should only be done for interventions that are associated with improved outcomes. At this time, there are insufficient data and evidence to support or refute any recommendations about checking a pulse during CPR.
 

Key components of high-quality CPR include minimizing interruptions, compressing at an optimal rate and depth, providing adequate chest recoil, and avoiding excessive ventilation.34,56,57 Although there are numerous retrospective observational studies, there is a paucity of prospective studies or randomized trials specifically examining CPR quality targets. Further, evidence suggests interactions between CPR components (eg, rate and depth) confound studying them in isolation. These limitations do not reduce the importance of these elements, rather they underscore the need for ongoing investigations into ideal CPR performance.

Recommendation-Specific Supportive Text

  1. A 2020 ILCOR scoping review56 identified 12 studies, including over 10 700 patients looking at chest compression depth. Several studies found improved survival to hospital discharge55,58,59 when compression depth was at least 5 cm, compared to less than 4 cm.58,59 Observational research has suggested reduced survival with chest compressions of excessive depth (greater than 6cm).58,59
  2. A 2024 ILCOR scoping review60 addressing real-time CPR audiovisual feedback for rescuers affirmed previous recommendations, however, with methodologic limitations of included studies.13 Many studies incorporated feedback devices into multifaceted quality improvement programs. A recent systematic review and meta-analysis showed that the use of audiovisual feedback devices was associated with improved rates of ROSC and survival to discharge from cardiac arrest, although not survival with favorable neurologic outcome.61 One randomized clinical trial of IHCA demonstrated an improvement of 25.6% in survival to hospital discharge by using audible feedback on compression depth and recoil.62
  3. A 2020 ILCOR scoping review identified 11 observational studies examining chest compression rate in adult patients in cardiac arrest.56 Three studies of over 13,700 patients57,63,64 suggested improved survival to hospital discharge with compression rates of 100 to 119/min, compared with lower or higher rates. One randomized trial found no difference in survival between chest compression rates of 100 and 120/min.65 In 1 study, ROSC was improved with higher rates (121–140/min) in comparison to 100 to 120/min (n=222)64; however, the writing group placed higher value on survival compared with ROSC when making this recommendation.
  4. Two observational studies provide mixed results for the effect of chest compression release velocity, with 1 study suggesting improved survival at rates greater than 400 mm/s,66,67 and the other suggesting no difference in outcomes.66 Porcine study data suggest decreased coronary perfusion with rescuers leaning on the chest.68
  5. The 2020 Guidelines recommended a 50% duty cycle, in which the time spent in compression and decompression was equal, mainly based on its perceived ease of being achieved in practice. In a clinical study in adults with out-of-hospital ventricular fibrillation (VF) arrest (of whom 43% survived to hospital discharge), the mean duty cycle observed during resuscitation was 39%.69 Although many animal studies have observed higher blood flows and better outcomes when the duty cycle was less than 50%, the optimal duty cycle is not known. Currently, there is insufficient evidence to warrant a change from the existing recommendation, which remains a knowledge gap that t