Single-Rescuer Adult Basic Life Support
An Advisory Statement From the Basic Life Support Working Group of the International Liaison Committee on Resuscitation
This document presents the consensus view of the Basic Life Support (BLS) Working Group of the International Liaison Committee on Resuscitation (ILCOR), which represents the world’s major resuscitation organizations (including the American Heart Association [AHA], the Australian Resuscitation Council, the European Resuscitation Council [ERC], the Heart and Stroke Foundation of Canada, and the Resuscitation Councils of Southern Africa). These advisory statements have evolved during 10 meetings of ILCOR from 1991 to the present.
The scientific basis for the treatment of cardiac arrest has an active international literature.1 The purpose of creating these advisory statements is to take full advantage of international perspective and experience in the basic management of cardiac arrest. It is hoped that the “Sequence of Action” can be used as a template by individual national resuscitation organizations. This template should not, however, be considered a rigid standard. It is intended primarily to remove the many minor international differences in BLS education that have developed over the last 30 years, often without any basis in science. For example, if the current BLS guidelines of the ERC and the AHA are compared, most of the differences exist without any particular rationale and are based simply on quirks of historical practice. It is hoped that by removing these, BLS training can become as uniform as possible throughout the world.
The process for the development of the advisory statements involved
1. Identification of major and minor differences between existing BLS guidelines.2 3 Minor differences mostly involved the use of words rather than any real differences of opinion about scientific content. They were resolved by arriving at a consensus.
2. Presentation of formal position papers on areas of major difference with an emphasis on available scientific evidence. The group attempted to reach consensus on items of controversy, but sometimes the resulting statements reflect a majority opinion.
3. Presentation of the newly developed guidelines to the ILCOR Advanced Life Support and Pediatric Working Groups with incorporation of the comments received.
4. Feedback from the individual national BLS Committees of the member resuscitation organizations.
5. Preparation of the final sequence of action which follows.
Sequence of Action
1. Ensure safety of rescuer and victim.
2. Check the victim for a response: • Gently shake the victim’s shoulders and ask loudly, “Are you all right?”
3. a.If there is a response (the victim answers or moves):
• Do not move the victim (unless he or she is in further danger), check the victim’s condition, and get help if needed.
• Reassess the victim’s condition regularly.
b.If the victim does not respond:
• Shout for help, send someone for help, or if you are on your own, consider leaving the victim and going for help.
• Open the victim’s airway by tilting the head and lifting the chin:
–If possible, without moving the victim from his or her original position, place your hand on the victim’s forehead and gently tilt the head back, keeping your thumb and index finger free to close the victim’s nose if rescue breathing is required.
–At the same time, with your fingertip(s) under the point of the victim’s chin, lift the chin to open the airway.
–If you have any difficulty, turn the victim onto his or her back and then open the airway as described. Avoid head tilt if trauma (injury) to the neck is suspected.
4. Keeping the airway open, look, listen, and feel for breathing (more than an occasional gasp):
• Look for chest movements.
• Listen at the victim’s mouth for breath sounds.
• Feel for air on your cheek.
• Look, listen, and feel for up to 10 seconds before deciding that breathing is absent.
5. a.If the victim is breathing (other than an occasional gasp):
• Place the victim in the recovery position.
• Check for continued breathing.
b.If the victim is not breathing:
• If you have not already done so, send someone for help, or if you are on your own, leave the victim and go for help; return and start rescue breathing as below.
• Turn the victim onto his or her back if the victim is not already in this position.
• Remove any visible obstruction from the victim’s mouth, including dislodged dentures, but leave well-fitting dentures in place.
• Give 2 effective rescue breaths, each of which makes the chest rise and fall.
–Ensure head tilt and chin lift.
–Pinch the soft part of the victim’s nose closed with the index finger and thumb of your hand on the forehead.
–Open the victim’s mouth a little, but maintain chin lift.
–Take a breath and place your lips around the victim’s mouth, making sure that you have a good seal.
–Blow steadily into the victim’s mouth over about 1.5 to 2.0 seconds, watching for the chest to rise.
–Maintaining head tilt and chin lift, remove your mouth from the victim’s mouth, and watch for the victim’s chest to fall as air comes out.
• Take another breath and repeat the sequence as above to give 2 effective rescue breaths in all.
• If you have difficulty achieving an effective breath:
–Recheck the victim’s mouth and remove any obstruction.
–Recheck that there is adequate head tilt and chin lift.
–Make up to 5 attempts in all to achieve 2 effective breaths.
–Even if unsuccessful, move on to assessment of circulation.
6. Assess the victim for signs of circulation:
• This includes
–Looking for any movement, including swallowing or breathing (more than an occasional gasp)
–Checking if the carotid pulse is present.
• Take no more than 10 seconds to do this.
7. a.If you are confident that you can detect signs of circulation within 10 seconds:
• Continue rescue breathing, if necessary, until the victim starts breathing on his or her own.
• About every minute, recheck for signs of circulation; take no more than 10 seconds each time.
• If the victim starts to breathe on his or her own but remains unconscious, place the victim in the recovery position. Check the victim’s condition and be ready to turn the victim onto his or her back and restart rescue breathing if breathing stops.
b.If there are no signs of circulation or if you are at all unsure:
• Start chest compression:
–Locate the lower half of the sternum (breastbone), and place the heel of one hand there, with the other hand on top of the first.
–Interlock the fingers of both hands and lift them to ensure that pressure is not applied over the victim’s ribs. Do not apply any pressure over the upper abdomen or bottom tip of the sternum.
–Position yourself vertically above the victim’s chest, and with your arms straight, press down on the sternum to depress it between 4 and 5 cm (1.5 to 2.0 inches).
–Release the pressure, then repeat at a rate of about 100 times a minute (a little less than 2 compressions per second). Compression and release should take an equal amount of time.
• Combine rescue breathing and compression:
–After 15 compressions, tilt the head, lift the chin, and give 2 effective breaths.
–Return your hands immediately to the correct position on the sternum and give 15 further compressions, continuing compressions and breaths in a ratio of 15:2.
8. Continue resuscitation until
• The victim shows signs of life.
• Qualified help arrives.
• You become exhausted.
Modification of the ILCOR BLS Sequence of Action
This BLS sequence of action is not intended to restrict national resuscitation organizations or prevent them from making modifications when valid concerns (or future studies) support these. It is fully anticipated that the significant differences in culture and emergency facilities that exist between communities will result in modification of these statements by national resuscitation organizations in order to meet specific local or regional needs. For example, decisions on when to call for help or whether to perform a pulse check may vary, depending on local epidemiology, emergency medical services (EMS) technology, or public cardiopulmonary resuscitation (CPR) education. Therefore, this template should be used as a basic resource from which to develop appropriate local BLS guidelines.
Lay Rescuer Training
Readers familiar with CPR guidelines from other sources will note that there are some differences between these statements and prior publications. A central concern has been to ensure that guidelines are as simple as possible. The reason for a movement toward simplicity comes from a critical examination of the successes and failures of public sector CPR education. There is no question that CPR saves lives, yet after 30 years of attempts at public CPR education, most communities still do not train a sufficiently high proportion of the public to perform basic CPR; rates of community CPR in the United States and Europe have not increased significantly since the 1970s. Paradoxically, in some higher-risk populations the rate of bystander CPR is particularly poor.4 5 Therefore, the ILCOR BLS Working Group recognizes that a redoubling of efforts to teach CPR to the public is a vital priority for nearly all communities.
There are many possible obstacles to layperson CPR training, the reasons for which are multifactorial. It has been noted by some investigators that the psychomotor skills required to perform CPR are relatively difficult for the lay public. Moreover, even when they are taught to professionals, their retention by people who do not use them regularly has been disappointing.6 7 8 In addition, in some communities there is a reluctance to perform rescue breathing on a stranger due to a concern over disease transmission, for example, a fear of contracting HIV.9 10
There is scientific uncertainty within the literature regarding how “good” CPR has to be in order to save a life.11 Do victims who receive perfectly performed compressions and rescue breathing (so called “good CPR”) fare better than victims who get less effective CPR? A definitive answer is still awaited, but the clear conclusion from many studies is that the lowest survival rates occur when there is no attempt at CPR.12 Any CPR is better than no CPR. Therefore, a simple, basic approach that can be effectively taught to the largest number of people should help to increase the pool of individuals willing to attempt BLS.
It is possible to imagine a wide spectrum of BLS instruction from simple to very complex. For example, some have suggested that CPR instruction for laypersons be as simple as “pump and blow.” By contrast, far more complicated protocols than those currently available could be developed and recommended for public education by addition of more medical assessment steps to the various maneuvers. The recipe for the most “simple CPR,” while maintaining effectiveness for survival, has not been adequately addressed.
It has been traditional when checking for cardiac arrest in a nonresponsive (unconscious) adult victim to palpate the carotid artery. To date, all resuscitation councils worldwide require this single determination of carotid pulselessness as the diagnostic step that immediately leads to the initiation of chest compression. The time allowed to feel for the existence of a pulse differs between resuscitation councils,2 3 13 but no council advocates >10 seconds for a normothermic victim, as time is critical when initiating CPR.
Should the carotid pulse check still be taught to laypersons as the sole criterion for the initiation of chest compression?
Many EMS dispatch centers now offer telephonic CPR instruction to callers reporting victims who have collapsed. The criteria for the initiation of CPR are normally a combination of unresponsiveness and lack of breathing.14 It is not normal practice for the dispatcher to ask for a carotid pulse check prior to advising chest compression, mainly because of the perceived difficulty in describing the technique over the telephone. Is the carotid pulse check in fact difficult, particularly for laypersons?
Recent studies15 16 17 18 19 have strongly suggested that the time needed to diagnose with confidence the presence or absence of a carotid pulse is far greater than the 5 to 10 seconds normally recommended, with times >30 seconds being needed to achieve a diagnostic accuracy of 95%. Even with prolonged palpation, 45% of carotid pulses may be pronounced absent when in fact present.19 It should also be borne in mind that most of the studies were undertaken using normotensive volunteers, a situation far different from finding a victim in the street who has collapsed and is in cyanosis and who is likely to have hypotension, vasoconstriction, or worse.
As a result of these studies, the BLS group considers that the carotid pulse check should be deemphasized and that other criteria should be used to determine the need for chest compression in an unresponsive, apneic adult patient. We decided to use the expression “Look for signs of circulation,” which includes looking for movement as well as checking the carotid pulse. The rescuer should limit the time taken for this check to ≤10 seconds. Therefore, the absence of any obvious signs of life, not necessarily the absence of the carotid pulse, should be sufficient indication to initiate chest compression.
It should be emphasized that this departure from current teaching is aimed, at least for now, only at the lay rescuer; checking for a pulse remains an important part of advanced life support (ALS) and the algorithm for use of automatic external defibrillators (AEDs).
Volume and Rate of Ventilation
Rescue breathing (expired air ventilation; mouth-to-mouth ventilation) has been a well-accepted technique of airway management in BLS since the early 1960s.20 The volume of air required for each inflation is normally quoted as 800 to 1200 mL, with each breath taking 1.0 to 1.5 seconds. The BLS group questioned the validity of these figures.
Artificial ventilation without airway protection (such as tracheal intubation) carries a high risk of gastric inflation, regurgitation, and pulmonary aspiration.2 The risk of gastric inflation depends upon (1) the proximal airway pressure, which is determined by tidal volume and inflation rate; (2) the alignment of the head and neck and degree of patency of the airway; and (3) the opening pressure of the lower esophageal sphincter (approximately 20 cm H2O).
It has recently been shown that a tidal volume of 400 to 500 mL is sufficient to give adequate ventilation in adult BLS because Co2 production during cardiac arrest is very low.21 This recommendation overrules earlier guidelines and makes it necessary to recalibrate adult training manikins.22 It is, however, consistent with the accepted teaching that the tidal volume should be that which causes the chest to rise as in normal spontaneous breathing.
During combined rescue breathing and chest compression, the rate of ventilation is dependent both on the ventilation volume and the compression rate. An inflation time of 1.5 to 2.0 seconds diminishes the risk of exceeding the esophageal opening pressure22 and results in an inflation/exhalation cycle of about 3 seconds. To obtain optimum perfusion of vital organs, a chest compression rate of about 100 per minute is recommended. It therefore takes 12 seconds to perform 15 cardiac compressions, allowing 6 seconds for the 2 rescue breaths; single-rescuer CPR should result in 8 breaths and 60 chest compressions per minute.
Call First—Call Fast
The first link in the “chain of survival”23 is to gain access to EMS. Advice as to the optimum time during a resuscitation attempt at which to leave the victim to go for help will depend on several factors: whether the rescuer is alone, whether the victim has a primary respiratory or primary cardiac arrest, the distance to the nearest point of aid (for example, a telephone), and the facilities offered by the emergency services.
The importance of early defibrillation in the treatment of sudden cardiac death is now accepted, and major initiatives are moving forward in the world to deliver a defibrillator and the first shock at the earliest possible moment.24 The 1992 AHA guidelines2 emphasized that the rescuer should, if no other help is available, leave an adult victim immediately after establishing unresponsiveness in order to call an ambulance or EMS system (“phone first”). The ERC guidelines3 advise that a shout for assistance should be made as soon as the victim is found to be unconscious but that the lone rescuer should not leave to go for help until cardiac arrest is diagnosed by means of a pulse check (“phone fast”). Both the AHA and the ERC guidelines seek to ensure that a defibrillator reaches the victim at the earliest appropriate opportunity. Both agree that if the victim is a child, the rescuer should provide rescue support (ventilatory or circulatory or both) for about 1 minute before leaving the victim and calling the rescue team.25
The rationale for phoning first (rather than fast) is based on several factors.26 Clearly, defibrillation is the key to survival from sudden cardiac death. However, it has been documented that rescuers finding unconscious victims frequently encounter psychological blocks that prevent them from starting CPR or even calling for help. Valuable minutes are lost because of this inactivity, resulting in less chance of survival for the victim. Other rescuers can become so consumed with providing CPR that they persist far too long before summoning the EMS system.
In children the etiology of cardiopulmonary arrest is different from that of the adult.27 Respiratory arrest is far more common than cardiac arrest, which, if it occurs, is usually secondary to respiratory arrest. The outcome of attempts at resuscitation from cardiac arrest in children is dismal at best, with a high chance of poor neurological status afterwards.28 Survival following cardiopulmonary arrest in children is dependent mainly upon the immediate provision of effective rescue breathing,29 hence the recommendation of 1-minute rescue support before leaving and phoning for help.
There has recently been interesting data to suggest that ventricular fibrillation is relatively rare in individuals up to the age of 30 years30 31 and that perhaps a similar strategy to that of the management of childhood cardiac arrest would be prudent up until this age.
The EMS system in the United States responds in a way that uses the AHA guidelines but also considers other causes of collapse with separate protocols to manage them. It is recognized that the result of the call first versus call fast debate will vary in different parts of the world because of the different ways in which EMS systems are composed and staffed, as well as their different approaches to first aid. For this reason the sequence of action includes two alternative points in time when the lone rescuer may consider leaving the victim to get help: after responsiveness is established or after the airway has been opened and breathing has been found to be absent.
In order to try and identify cases of primary respiratory arrest, 1 minute of resuscitation is advised when dealing with children and victims of trauma and near drowning. The following statement embodies the discussions above:
When to Get Help
• It is vital for rescuers to get help as quickly as possible.
• When more than one rescuer is available, one should start resuscitation while another rescuer goes for help.
• A lone rescuer will have to decide whether to start resuscitation or to go for help first. In these circumstances, if the likely cause of unconsciousness is trauma (injury) or drowning or if the victim is an infant or a child, the rescuer should perform resuscitation for about 1 minute before going for help.
If the victim is an adult, and the cause of unconsciousness is not trauma (injury) or drowning, the rescuer should assume that the victim has a heart problem and go for help immediately when unresponsiveness is established or after establishing unresponsiveness and the absence of breathing.
Action for Choking
Action for choking, in particular the abdominal thrust maneuver, is included in most BLS guidelines. However, the incidence of an impacted foreign body in the airway is extremely low compared with the incidence of cardiac arrest from other causes. Indeed, most medical practitioners will never have encountered foreign matter in the airway that has caused death or even near death. Most cases of impacted food occur when the victim is eating, frequently while in the presence of other people. The event is therefore commonly witnessed. It also usually results in a progressively worsening situation of aphonia, cyanosis, and loss of consciousness rather than sudden collapse, sharply contrasting with most cases of primary cardiac arrest.
The BLS group decided therefore not to include the abdominal thrust maneuver as part of BLS, not only because it will be rarely needed, but because the technique carries significant added risks, including gastric aspiration and damage to abdominal organs. Chest compression applied for cardiac arrest produces a significant increase in intrathoracic pressure, and in the unlikely event of there being impacted material may well be sufficient to clear the airway.
By eliminating the abdominal thrust from the teaching of BLS there is the additional benefit that one less skill has to be learned, which should benefit long-term skill retention.
The airway of an unconscious victim who is breathing spontaneously is at risk of obstruction by the tongue and from inhalation of mucus and vomit. Placing the victim on his or her side helps to prevent these problems and allows fluid to drain easily from the mouth. This lateral, coma, side, or recovery position has been advocated in anesthesia for over 100 years32 and is still standard practice today. It is surprising therefore that its introduction into first aid practice was within the last 50 years.33 Perhaps even more surprising is that it was not until 1992 that the AHA guidelines mentioned the recovery position.2
Some compromise is needed when positioning the victim; a true lateral posture tends to be unstable, involves excessive lateral flexion of the cervical spine, and results in less free drainage from the mouth. A near-prone position, on the other hand, can result in underventilation because of splinting of the diaphragm and reduction in pulmonary and thoracic compliance.34
Potential injury to the victim also has to be considered.35 There have been a number of recent reports of potential interference with upper limb blood flow associated with the recovery position advocated by the ERC.36 37 This involves the lowermost arm being brought into a ventral position with the uppermost arm crossing it and producing a pressure effect on the blood vessels and, possibly, the nerve supply. Placing the lowermost arm in a dorsal position may not necessarily be the answer, as this involves movement that could, at least theoretically, injure the shoulder joint. There is inadequate published evidence to come to definite conclusions, but the recognition of the potential for harm as well as for benefit from placing the victim on the side has been highlighted.
Many different versions of the recovery position exist, each with its own advocates. The BLS group concluded that it was unable to recommend one specific position but instead agreed on six principles that should be followed when managing the unconscious, spontaneously breathing victim:
1. The victim should be in as near a true lateral position as possible, with the head dependent to allow free drainage of fluid.
2. The position should be stable.
3. Any pressure on the chest that impairs breathing should be avoided.
4. It should be possible to turn the victim onto his or her side and return to the back easily and safely, having particular regard for the possibility of cervical spine injury.
5. Good observation of and access to the airway should be possible.
6. The position itself should not give rise to any injury to the victim.
Healthcare providers and emergency personnel are likely to possess extended resuscitation skills, and the situations in which they are called upon to use them may require more complicated BLS guidelines. These requirements have not been addressed in the current advisory statements, which are aimed predominantly at laypersons. They are, however, planned as the subject of a future ILCOR publication.
Automated External Defibrillators
The use of an AED is now considered to be within the domain of BLS.38 In fact, learning to use an AED may be easier than learning the skills required to perform CPR. Most investigators believe that these devices should be distributed as widely as possible. Over the last 5 years the use of AEDs has been extended to include emergency medical technicians (EMTs), firefighters, police, airline personnel, hospital personnel, and lay citizens.39 The AHA statement on public access defibrillation lays down scientific evidence for the widest practical distribution of these devices throughout all communities.38 However, there is not yet sufficient worldwide experience, nor is there sufficient worldwide availability of AEDs to warrant inclusion of training in their use in the current BLS sequence of action. Nevertheless, it should be noted that many resuscitation organizations are already adding training in the use of an AED to their BLS programs in the hope of saving more lives.
Early CPR coupled with early defibrillation is a very powerful combination that improves survival from cardiac arrest. The expansion of early defibrillation into BLS is expected to continue in the future. Resuscitation organizations would do well to consider this when customizing the ILCOR BLS template to serve the particular needs of their region.
Correspondence should be sent to Dr Anthony J. Handley, Colchester General Hospital, Turner Road, Colchester, Essex CO4 5JL UK.
ILCOR BLS Working Group
Anthony J. Handley, MD, FRCP, Chair; Lance B. Becker, MD, Cochair; Mervyn Allen, MD, FRACA; Nisha C. Chandra, MD; Wolfgang F. Dick, MD; Ank van Drenth, MD; Ahamed Idris, MD; Efraim B. Kramer, MD; William H. Montgomery, MD.
↵1 Resuscitation Councils of Southern Africa
↵2 American Heart Association
↵3 European Resuscitation Council
↵4 Australian Resuscitation Council
5 Heart and Stroke Foundation of Canada.
‘Single-Rescuer Adult Basic Life Support’ was approved by the American Heart Association Science Advisory and Coordinating Committee in February 1997.
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- Copyright © 1997 by American Heart Association
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