Unresponsive and abnormal breathing (adolescent and adult)

Immediately start chest compressions and access emergency medical services.

 

 

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If a person’s heart is unable to pump enough blood around the body, then this person is in cardiac arrest. The person will quickly become unresponsive and display signs of abnormal breathing (e.g., taking irregular or noisy breaths, or stop breathing altogether). When a person’s heart is not working and they are not breathing, their body experiences a lack of oxygen. Vital organs, such as the brain or the heart, can start to deteriorate after a few minutes. Sudden cardiac arrest is one of the leading causes of death worldwide (Berdowski et al., 2010). Early recognition of abnormal breathing and provision of CPR  can keep the person alive until defibrillation takes place, either by a first aid provider or professional responder.

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NOTE

The techniques of CPR need to be adapted depending on the size of the unresponsive person and the size of the first aid provider. Use the following guidelines on an unresponsive person who looks like an adolescent or adult, (you think they have been through puberty). If the person is an adolescent, consider giving rescue breaths. If the person looks like they are a child, follow the guidelines for Unresponsive and abnormal breathing (baby and child).

It is most important to do something. In the case of someone needing CPR, it is unlikely a first aid provider can make the situation worse for the person.

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Guidelines

  • If a person is unresponsive with abnormal or no breathing, it is reasonable to assume the person is in cardiac arrest. **
  • Taking the pulse as the sole indicator of the presence or absence of cardiac arrest is unreliable. **
  • When possible, a lone bystander with a mobile phone should call for help, activate the speaker or other hands-free option on the mobile phone, and immediately begin CPR with dispatcher assistance, if required. **
  • If in doubt whether a person is experiencing cardiac arrest or not, the first aid provider should start CPR without concern of causing additional harm. **
  • First aid providers who are trained, able and willing can give rescue breaths and chest compressions to all unresponsive adolescents and adults with abnormal breathing. *
  • CPR may start with compressions rather than rescue breaths. *
  • Chest compressions may be performed in the centre of the chest (i.e., the lower half of the sternum or breastbone) on adolescents and adults who are unresponsive with abnormal breathing. *
  • Chest compressions should be performed fast, at a rate of 100 to 120 per minute. **
  • Chest compressions should be done to a depth of approximately 5 cm (2 inches); a compression depth of more than 6 cm (2.4 inches) should be avoided. **
  • Chest compression may be performed on a firm surface when possible. *
  • First aid providers should avoid leaning on the chest between compressions to allow full chest wall recoil. **
  • For those who are willing and able to provide rescue breaths, a ratio of 30 compressions and 2 rescue breaths (30:2) should be used on people who are unresponsive with abnormal breathing. **
  • Interrupting chest compressions to deliver two rescue breaths should take less than ten seconds. **
  • Where an automated external defibrillator is available, first aid providers should continue to perform CPR while the defibrillator is set up and pause only when it is ready for analysis and, if indicated, provides a shock. **
  • In any setting, chest compressions can be resumed immediately after shock delivery for adolescents or adults who are unresponsive with abnormal breathing. Any pauses in chest compressions before and after the shock should be as short as possible. **

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The following guidelines are specific to emergency medical dispatch centres and the professionals who work there.

  • Emergency medical dispatch centres should implement a standardised algorithm or criteria to determine immediately if a person is unresponsive with abnormal breathing at the time of an emergency call. **
  • Emergency medical dispatchers should be educated to identify unresponsiveness with abnormal breathing. This education should include recognition and significance of agonal breaths across a range of clinical presentations and descriptions. **
  • Emergency medical dispatch centres should have systems in place where dispatchers can provide instructions to callers who will provide CPR. Dispatchers should provide chest-compression-only CPR instructions. **

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 Good practice points

  • To achieve more effective chest compressions the dominant hand should be placed against the sternum with the non-dominant hand over the first.
  • If the person is an adolescent, CPR with rescue breaths is preferred.
  • Adults receiving CPR will require onward medical care. In contexts where this care is unavailable, first aid providers should prioritise the dignity of the person they are caring for.

Guideline classifications explained 

Chain of survival behaviours

Prevent and prepare
  • There are national and global organisations that research how to reduce the likelihood of cardiac arrest and set up national and regional cardiac arrest registers to define a strategy of intervention. Refer to your country’s health authority for more information.
  • Make healthy lifestyle choices to minimise certain risk factors such as high blood pressure, obesity, blood sugar level, hyperlipidaemia and renal dysfunction. Avoid activities such as smoking.
  • Promote emergency phone numbers and other means to access help fast.
Early recognition

There are two main types of cardiac arrest that result in unresponsiveness and abnormal breathing. The first is when the heart stops suddenly (e.g., from a heart attack). This is the most common type in adults; it prevents the oxygen-rich blood from pumping around the body. The second type is when a person is unable to breathe oxygen into the body (e.g., due to drowning or strangulation). The person will have very little oxygen remaining in their blood.

In the first few minutes after cardiac arrest, a person may have agonal breathing (meaning they are barely breathing or gasping noisily). This type of breathing is not normal. If there is any doubt about whether breathing is normal, assume it is not. Similarly, for professional responders, if you are unsure if a pulse is present, assume it is not.

Check for a response by gently shaking the person’s shoulders. Speaking loudly and clearly, ask a question such as, “Are you alright?”.

If the person responds, see General approach.

If the person does not respond:

1. Open their airway: Gently tilt their head back until the mouth falls open and lift the person’s chin. (You may need to turn the person onto their back to do this.)

2. Check for breathing: Keeping the airway open, look, listen and feel for normal breathing for up to ten seconds. Look for chest or abdominal movement; listen for breath sounds; feel for air on your cheek. Professional responders may also do a pulse check at this time.

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NOTE

Identify that the person is an adolescent or an adult. If they are a child, follow the approach for Unresponsive and abnormal breathing (baby and child).

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First aid steps

If the person’s breathing is abnormal or they are not breathing:

1. Immediately ask bystanders to access emergency medical services (EMS), or if you are alone access EMS yourself. If using a phone, activate the speaker function.

2. Begin chest compressions without delay; push down on the centre of the person’s chest at a fast and regular rate (100–120 compressions per minute).

3. Continue to give chest compressions unless otherwise instructed to pause (either by an automated defibrillator or professional responder). Pause compressions if the person shows signs of recovery, such as coughing, opening their eyes, speaking or moving purposefully and breathing normally.

NOTE

  • If one is available, ask a bystander to bring an automated external defibrillator as soon as possible. Follow the voice prompts, interrupting chest compressions as little as possible. (See Unresponsive and abnormal breathing when a defibrillator is available.)
  • If able and willing, combine chest compressions and rescue breaths at a ratio of 30:2 (30 compressions and two breaths). Rescue breaths can benefit people who are unresponsive because they were unable to breathe. Conditions include Drowning, Choking, strangulation, opioid overdose or babies and children. Rescue breaths may also be beneficial if there is likely to be a delay in defibrillation.
  • If more than one first aid provider is present, alternate giving chest compressions every one to two minutes to prevent getting tired. Ensure that there is no interruption in compressions as the next person takes over.
Local adaptation
  • If transporting the person from a remote area to medical care, continuous CPR on a firm surface must be provided during transit.
  • Where EMS or other forms of onward care is not available, protect the person’s dignity.
  • If a person has drowned or has hypothermia, there is a chance they may respond to CPR even if defibrillation is not possible.
Access help
  • When speaking to EMS, very clearly explain that the unresponsive person is not breathing normally; this will prompt EMS to prioritise your case appropriately.
  • Ask bystanders for help accessing EMS and providing CPR, as well as bringing and using an automated external defibrillator.
  • An unresponsive person who is not breathing is unlikely to achieve spontaneous circulation from CPR alone. Their heart needs an electric shock from a defibrillator. It is vital that EMS arrive, and a defibrillator is used.
  • The survival of the person depends upon immediate and effective CPR; when accessing help, keep any interruptions to chest compressions minimal.
Self-recovery
  • Even if the first aid provider has performed CPR and defibrillation and the person is now responsive and breathing normally, you must continue close monitoring until EMS arrives as the person may stop breathing again.

Education considerations

Supporting learners to have the confidence and willingness to attempt CPR on a person who is unresponsive and breathing abnormally is a priority for first aid educators.  Remember that the opportunity to provide CPR is generally very low – some learners might never have to perform it.  However, if such a situation does arise, learners need to be prepared for feelings of doubt, uncertainty and lack of confidence.  Therefore, CPR education should always take these feelings into account, and support the learner to overcome them.

Context considerations
  • Refer to and follow the guidance of regional resuscitation councils or other national protocols and tailor education accordingly.
  • Consult local regulators to consider differences in regulation and liability protection for first aid providers.
  • Where EMS is available, learners should be encouraged to start compression-only CPR rather than hesitate as they consider the possibility of rescue breaths.
  • In some countries, specifically those with a high rate of tuberculosis, rescue breaths may be discouraged. Teach first aid providers chest compression-only CPR (or bag-valve-mask resuscitation if they are professional responders). Also, see Pandemic.
  • In contexts where there isn’t any EMS or access to onward care, prepare learners for the likely death of the person who is unresponsive and has abnormal breathing. This should include telling them what to do according to local regulations and requirements for registering a death.
Learner considerations
  • Prioritise training community members most likely to encounter cardiac arrest emergencies in CPR. Members include but are not limited to medics, police officers, firefighters and lifeguards. Also, consider that these groups, given their status and role in the community, might make effective educators for the general public (Tweed and Wilson, 1977). Despite advances in resuscitation science and standardised life-support methods, the overall survival rate of out-of-hospital cardiac arrests remains at less than 10% (Bobrow et al., 2010; Kazaure et al., 2013).
  • Build on the motivation that people with family members who are at high risk of cardiac arrest due to illness might have to learn first aid (See Motivation to learn; Huang et al., 2016).
  • Adapt educational tools (e.g. manikins and defibrillators), locations (e.g., waterfront scenarios for lifeguards) and methods to make them accessible and appropriate for learners’ needs and abilities. (Papalexopoulou et al., 2014; Sopka et al., 2013).
  • Consider that age and size of learners. The depth of compressions that can be achieved correlates with physical factors such as increasing weight and height. Children between 10 and 13 may be able to deliver effective chest compressions (Plant, 2013).
  • Remind learners that they are most likely to witness the collapse of a person who they know (such as a member of their household), rather than a stranger because in general, we spend more time with people we know.
  • Some studies noted that bystanders have concerns about disease exposure and transmission through standard CPR, which has caused a significant decrease in their willingness to provide it to both strangers and family members. Compression-only CPR is the preferred method (Cheng-Yu et al., 2016; Jelinek et al., 2001; Lam et al., 2007; Pei-Chuan Huang et al., 2019).
  • Consider the gender makeup of a group of learners. There is limited evidence to demonstrate that female-only learner groups are beneficial to female learners, but there is evidence to support that males are more likely to learn in mixed groups (Sopka et al., 2013).

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These considerations are specific to emergency medical dispatchers.

  • Emergency medical dispatchers play a critical role by promptly recognising cardiac arrest, providing CPR instructions by phone and dispatching EMS with a defibrillator. Consider as part of the education for this role:
    >    The use of scripted protocols as a helpful way to confirm when a person is in cardiac arrest.
    >    Additional training around the recognition of agonal breathing.
    >    How to provide CPR instructions for an adult.
    >    How to provide instructions for both rescue breaths and compressions if the person is a baby or child.
  • Dispatchers who communicate using video-assisted emergency calls may need more training for this tool to be effective and widespread within CPR education (Bolle et al., 2009). Bang et al. (2000) suggest that dispatchers with further training (e.g. technical and emotional) are more effective.

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Facilitation tips
  • Emphasise that survival relies upon:
    >    immediate recognition that someone is unresponsive and breathing abnormally
    >    early access to help and EMS
    >    early high-quality CPR (compression-only or standard CPR)
    >    early defibrillation with an automated external defibrillator.
  • Emphasise the importance of the first aid provider, other bystanders and EMS working together to provide quick and effective care.
  • Help learners understand the desired outcomes of CPR – to pump blood around the body (chest compressions) and get oxygen into the lungs (rescue breaths). This keeps the vital organs like the brain alive until defibrillation can take place.
  • Define proper compression rate and depth and highlight that the unresponsive person will have the best chance of recovery if chest compressions are of good quality.
  • Emphasise that the person should be lying flat on a firm surface if possible.
  • Emphasise that starting CPR early has a significant impact on the likelihood of achieving the return of spontaneous circulation for some people experiencing cardiac arrest. However, overall, the likelihood of return of spontaneous circulation remains low.
  • Ensure learners understand the fundamental components of standard CPR before being taught compression-only CPR (Lam et al., 2007).
Facilitation tools
  • If instructing learners on how to perform chest compressions and rescue breaths, refer to the resource Facilitating CPR skills (adolescent and adult). See also Pandemic.
  • Massive multiplayer virtual worlds allow learners to play a role and experience “real-life” scenarios and environments in which to practise their CPR skills. If implementing this tool, ensure facilitators understand how to use it and that the technology is not too complex (Creutzfeldt et al., 2013). (See Gamification, and Online learning for adults.)
  • If video-assisted dispatcher support is provided in your country, explain how this might work so that learners are prepared to use it, if available. Use role-play to help learners to understand what happens when they call an emergency number. (Bolle et al., 2009; 2011).
  • In settings without manikins, used car tyres could be used to practise CPR compressions. Dig the tyre about two-thirds of the way into the ground to simulate a chest, which will recoil when pushed on.
  • For learners who train regularly and are knowledgeable in CPR, extend skills training to include performing CPR in different settings and situations (e.g., in noisy or distracting environments, with anxious relatives present, in crowds or small spaces with restricted access). Such training exercises stimulate team-based approaches and lateral thinking.
  • Use film clips or demonstrations to improve learners’ recognition of abnormal breathing including agonal breathing and someone who is not breathing.
Learning connections

Consider other topics such as Acute grief and Traumatic event if appropriate to the learners.

Scientific foundation

Prompt recognition of cardiac arrest

In 2010, the International Liaison Committee on Resuscitation (ILCOR) conducted an evidence summary on the recognition of cardiac arrest (Koster et al., 2010). In this context, recognition of cardiac arrest includes checking the pulse and recognising agonal breathing.

To date, there are no studies that assess the accuracy of checking the pulse to detect cardiac arrest. Additionally, first aid providers have difficulty mastering the pulse check and remembering how to perform it.

There is often a high frequency of agonal gasps after cardiac arrest, but several studies showed that first aid providers and EMS dispatchers often do not recognise them. There are many terms used to describe abnormal breathing, confusing first aid providers and dispatchers alike. Sometimes these terms are limited due to cultural influences and translation limitations, even in the same country. Teaching people to identify agonal breathing using a video clip improved the accuracy of recognising cardiac arrest.

Evidence shows that with EMS dispatchers, failure to recognise cardiac arrest may be associated with a failure to follow cardiac arrest protocols while on the call. In a seizure complaint question sequence used by dispatchers, the detection of cardiac arrest cases improved after introducing the question, “Is he breathing regularly?” Special courses aimed at teaching dispatchers to identify agonal breathing also increased their ability to recognise cardiac arrest.
 

Chest compression-only CPR versus standard CPR

Many studies were conducted to evaluate chest compression-only CPR versus standard CPR with or without dispatcher instruction. We used two systematic reviews, one from ILCOR (Olasveengen et al., 2017) and one from Cochrane (Zhan et al., 2017) and the adult basic life support, 2020 international consensus on CPR from ILCOR (Olasveengen, 2020).
 

Compression-only CPR versus standard CPR

For the critical outcome of survival with favourable neurological function, a meta-analysis of two cohort studies showed no significant difference between people who received compression-only CPR compared to people who received CPR with a compression-to-rescue-breath ratio of 15:2. Further, a different meta-analysis of three studies, this time using CPR with a compression-to-rescue-breath rate of 30:2, also showed no significant difference in the outcome.

For the critical outcome of survival only, a meta-analysis of six studies did not demonstrate significant differences in people who received compression-only CPR compared to those who received standard CPR with a compression-to-rescue-breath ratio of 15:2. One study showed that people who received compression-only CPR had a worse survival rate than those who received CPR with a compression-to-rescue-breath ratio of 30:2. In another meta-analysis of three observational studies, there was no significant difference between people who received either type of CPR (compression-only or standard with a rate of 30:2).

For the important outcome of return of spontaneous circulation, a meta-analysis of three cohort studies showed no benefit to using the 15:2 ratio compared to using a different ratio.

The Cochrane systematic review compared chest-compression-only-CPR versus standard CPR on non-asphyxial out-of-hospital cardiac arrest. The meta-analysis found high-quality evidence that continuous chest compression CPR without rescue breathing improved people’s survival to hospital discharge compared to interrupted chest compressions with pauses for rescue breathing (ratio 15:2).
 

Compression-only CPR versus standard CPR (adults) – dispatcher-assisted

Low-quality evidence from a randomised controlled trial demonstrated no benefit to favourable neurological function when dispatchers provided instructions for continuous chest compressions compared to instructions for compressions and rescue breaths at a ratio of 15:2. Conversely, three randomised controlled trials also compared the two types of dispatcher-assisted CPR and found that compression-only CPR resulted in a small benefit to peoples’ survival to hospital discharge.

In the nationwide recommendation of compression-only CPR for first aid providers in Japan, results associated dispatcher-assisted compression-only CPR with improved bystander CPR rates. However, the outcome for people receiving CPR was better when bystanders performed standard CPR rather than compression-only.
 

First aid provider fatigue in chest-compression-only CPR

A comparison of first aid provider fatigue in chest compression between first aid providers who perform compression-only CPR versus standard CPR has been the subject of scoping review for the 2020 ILCOR recommendation. Fifteen manikin studies evaluating fatigue and its effects on CPR quality in volunteers performing continuous compressions and 30:2 or 15:2 CPR. They suggest that continuous compressions are effective in the first two minutes with regard to depth and frequency, and there are indications that short periods of rest (pauses in compression) reduce first aid provider fatigue and increase CPR quality.
 

Chest compression quality
Hand position during compression

The recommendations for hand position during compressions, based on only low- or very-low-certainty evidence in 2015 was reviewed in 2020. No studies reporting favourable neurological outcome, survival, or return of spontaneous circulation.  Only two observational studies that reported physiological endpoints are found. One study with a few people who received prolonged resuscitation from nontraumatic cardiac arrest observed improved peak arterial pressure and ETCO2  during compression systole when compressions were performed over the lower third of the sternum compared with the centre of the chest. The other physiological endpoints did not differ in this study and the second one, in 30 adults with cardiac arrest, observed no difference in ETCO2 values resulting from changes in hand placement.
 

Chest compression rate

The scientific foundation for chest compression rate includes an evidence summary completed by ILCOR (Perkins et al., 2015) and a scoping review by ILCOR (Considine et al., 2019) which served as the basis for the adult basic life support, 2020 International Consensus on CPR from ILCOR (Olasveengen, 2020, S41).

There was an inconsistent association between chest compression rate and survival with a favourable neurological outcome. The results varied depending on the study population (adult versus child), study size and whether any adjustments were made for potential confounders.

One study reported that when it adjusted for confounders, including compression depth and fraction , survival to hospital discharge was lower when compression rates were 80–99 and 120–139/min, compared to 100–119/min. No other studies reported specific compression rates benefitting the survival to hospital discharge outcome.

There were no significant differences reported between various chest compression rates on one-month survival, one-day survival, or hospital admission while alive. Of the eight studies that examined spontaneous circulation return, one study said that, compared to a reference chest compression rate of 100–120/min, 121–140/min was associated with an increased return of spontaneous circulation. Another study associated higher mean chest compression rates with an increased likelihood of spontaneous circulation return. None of the three studies that reported on blood pressure showed a significant effect between chest compression rate and either systolic or diastolic blood pressure.
 

Chest compression depth

The scientific foundation for chest compression depth includes an evidence summary completed by ILCOR (Travers et al., 2015 S51) and a scoping review by the Basic Life Support ILCOR task force (Considine et al., 2019). This served as the basis for the adult basic life support, 2020 International Consensus on CPR from ILCOR (Olasveengen, 2020, S41). Four observational studies suggest that the return of spontaneous circulation with a compression depth of more than 5 cm in adults is more likely than all other compression depths. Another study suggested that deeper chest compressions were associated with a greater likelihood of successful defibrillation.

For survival to hospital admission, one study showed that increased chest compression depth was associated with increased odds of admission to a hospital alive, while another study showed no association between different mean chest compression depths and survival to hospital admission.

Three studies compared different chest compression depths with survival and a favourable neurological outcome. None of the chest compression depths significantly increased or decreased survival or favourable neurological outcomes. However, one observational study suggests that a compression depth in adults of more than 5 cm increased survival and good neurological outcomes, compared to all other compression depths during standard CPR.

For survival, three studies reported statistically significant relationships between one-day survival and chest compression depth in adults. For each 5 mm increase in chest compression depth, one-day survival increased. One study that looked at survival to the emergency department showed that mean chest compression depths of 5–6 cm had the highest survival to emergency department rates in adults.

One study reported that survival to hospital discharge decreased when chest compression depth was less than 38 mm, compared to more than 51 mm and adjusting for confounders. Two adult studies reported that for each 5 mm increase in chest compression depth, survival to hospital discharge increased.

At least one study detailed injury frequency and showed that increased chest compression depths were associated with higher injury rates. The mean chest compression depth of people with injuries was 56 mm versus 52 mm in people with no injuries.
 

Chest wall recoil

The scientific foundation for chest wall recoil includes an evidence summary completed by ILCOR (Perkins et al., 2015) and a scoping review by ILCOR (Considine et al., 2019). This served as the basis for the adult basic life support, 2020 international consensus on CPR from ILCOR (Olasveengen, 2020, S41). The first two outcomes examined were favourable neurological outcomes and survival to hospital discharge. Two studies had conflicting results, while another study reported that – once adjusted for confounders – there was no difference in survival to hospital discharge associated with different chest compression release speed. One study reported the return of spontaneous circulation and showed no statistically significant improvement associated with a 10 mm per second increase in chest compression release speed. Only animal studies have found reduced coronary perfusion pressure with incomplete chest recoil.
 

Check for circulation during basic life-support

There is no evidence to justify doing further research and changing the 2015 treatment recommendation. Outside the advanced life-saving environment, there is insufficient data about the value of a pulse check while performing CPR.
 

Firm surface for CPR

For this topic, we use the adult Basic Life Support, 2020 International Consensus on CPR from ILCOR (Olasveengen, 2020, S41). Variation in backboard use and the practice of moving a person from the bed to the floor to improve the quality of CPR are reported. The identified science has been grouped by mattress type, floor compared with bed and backboard. Four manikin randomised controlled trials did not identify a difference in chest compression depth between mattress types. Two manikin meta-analyses found no effect on chest compression depth and neither two manikin trials identified a difference in chest compression depth between groups. At least, six manikin randomised controlled trials found that the effect of chest compression is improved when they are used on the backboard and one randomised controlled trial did not find a better effect. It’s important to indicate that we have no clinical studies reporting on the critical outcomes of survival and favourable neurological outcome or important outcome of chest compression quality. 

Harm caused by CPR to a person who is not in cardiac arrest

This topic’s scientific foundation includes an evidence summary from a systematic review, the Consensus of Science, and a Basic Life Support ILCOR task force treatment recommendation from Svavarsdottir et al. (2019).

Many first aid providers are concerned that they will harm a person who is not in cardiac arrest or cause severe complications by giving chest compressions. This belief makes them reluctant to start CPR. The systematic review included four observational studies that looked at 762 people who were not in cardiac arrest but still received CPR by first aid providers outside the hospital. Pooled data of three of these studies found an incidence of muscle damage of 0.3%, bone fracture (rib and clavicle) of 1.7%, pain in the area of chest compression of 8.7% and no visceral injury. The fourth study reported no injury.
 

Harm to rescuer from CPR

This topic has not been updated since 2010 and only concerned injury from CPR to people who are not in cardiac arrest (see above). It also reviewed any potential harm to the first aid providers during CPR, including harm during chest compressions, during rescue breaths, and with the use of defibrillators. Since 2008, no randomised controlled trials were identified for this topic and most identified studies addressed the safety of shock delivery during chest compressions when first aid providers wore gloves. Despite limited evidence evaluating first aid provider safety, there was a lack of published evidence supporting the interpretation that CPR is generally safe for first aid providers. Some reports demonstrate the possibility of disease transmission while performing rescue breaths and that CPR is relatively safe. Delivery of a shock with an automated defibrillator during basic life support is also safe. The incidence and morbidity of defibrillator-related injuries in the first aid providers are low. Note that these studies are all prior to COVID-19, see Pandemic.
 

CPR before calling for help

For this topic, we used the adult Basic Life Support, 2020 International Consensus on CPR from ILCOR (Olasveengen, 2020, S41). The optimal sequence for calling for help and starting CPR frequently arises during CPR education and was the subject of a new question and recommendation in 2020. Increased availability of phones and hands-free options for lone first aid providers were considered important.

For the critical outcome of survival with favourable neurological outcome, only one observational study is identified, and no meta-analysis found. This cohort study from Japan showed no benefit from a “CPR-first” strategy compared with a “call-first” strategy.

Adjusted analyses were performed on various subgroups and suggested significant improvements in survival with a favourable neurological outcome with a “CPR-first” strategy compared with a “call-first” strategy for non-cardiac etiology, out of hospital cardiac arrest, under 65 years of age, under 20 years of age and both under 65 years of age and noncardiac etiology together. The overall certainty of the evidence was rated as very low. The results are not generalisable to all out of hospital cardiac arrests because they refer specifically to bystander-witnessed cases in which the bystander spontaneously initiates CPR after only a short delay.
 

Starting CPR: rescue breaths or compression?

This topic’s scientific foundation includes the ILCOR treatment recommendation from Considine et al. (2019) and the adult Basic Life Support, 2020 International Consensus on CPR from ILCOR (Olasveengen, 2020, S41). This current systematic review did not identify any additional human or manikin studies published since the 2015 ILCOR systematic review.

There are three manikin studies on whether to start CPR with chest compressions or rescue breaths. All the studies found that beginning CPR with compressions first (30:2) compared to CPR beginning with rescue breaths first (2:30) significantly decreased the time to commencement of chest compression and seemed to decrease the time needed to complete the first CPR cycle. For time to commence rescue breaths, the results are conflicting between studies. The evidence is of very low quality.

 

Compression-to-rescue-breath ratio

In 2017 ILCOR completed an evidence summary on the ratio of compressions and rescue breaths during CPR, which we used to inform this section of the scientific foundation (Olasveegen et al., 2017). A meta-analysis of two observational cohort studies looked at the critical outcome of survival with a favourable neurological function. The results demonstrated that the 30:2 compression-to-rescue-breath ratio was more beneficial compared to a different ratio. Evidence is of very low quality.

Furthermore, a meta-analysis of six cohort studies showed that the survival rate was higher in the group of people who received the 30:2 ratio compared to the group who received 15:2. One retrospective cohort showed improved survival with a rate of 50:2 compared to 15:2 compressions to rescue breaths, but the evidence is of very low quality.
 

Reducing pauses between chest compressions

For this topic, we used an evidence summary from ILCOR, completed in 2015 (Perkins et al., 2015). Some CPR guidelines recommend pausing no more than five seconds to provide rescue breaths. First aid providers also have to pause compressions when using a defibrillator during pre-shock and post-shock intervals. Pre-shock intervals refer to the time required to assess the rhythm of a person in cardiac arrest and post-shock intervals refer to the time between shock delivery and when it is safe to resume compressions. One observational study indicated that shorter pre-shock pauses benefitted shock success.

One observational study showed that limiting pre-shock and post-shock pauses benefitted the return of spontaneous circulation, while another observational study suggested that achieving chest compression fractions (i.e., the total CPR time devoted to compressions) greater than 40% also benefitted this outcome.

For the outcome of survival to hospital discharge, three observational studies with 3,327 people demonstrated that shorter pre-shock and post-shock pauses produced a better outcome for people. However, one randomised controlled trial comparing two automated external defibrillator algorithms found no differences.
 

Rhythm-check timing

This topic’s scientific foundation includes an ILCOR treatment recommendation from Ristagno et al. (2019) and the adult Basic Life Support, 2020 International Consensus on CPR from ILCOR (Olasveegen et al., 2017).

There is some correlation between the interruption of chest compressions and adverse outcomes. One of the most common disruptions is checking cardiac rhythm after defibrillation. Still, any unnecessary pausing in chest compressions might impact the result of cardiac arrest.

Regarding the outcome of survival with a favourable neurological outcome at discharge, we looked at one randomised controlled trial and three observational studies. Both the trial and the studies assessed the effect of interrupting chest compressions to check the rhythm immediately after shock delivery. The randomised controlled trial included 415 out-of-hospital cardiac arrests and showed no benefit to interrupting chest compressions. Conversely, the three observational studies, which had 763 out-of-hospital cardiac arrests,  showed harmful effects when chest compressions were interrupted.

We also looked at the available evidence to see if the same chest compression interruption (to check the rhythm right after shock delivery) affected the outcome of survival to hospital discharge. Two randomised controlled trials with 1,260 out-of-hospital cardiac arrests showed no benefit to interrupting chest compressions. In contrast, three observational studies with 3,094 out-of-hospital cardiac arrests showed harmful effects when checking the rhythm immediately after defibrillation.

Further, for the outcome of survival to hospital admission, the results from two randomised controlled trials, totalling 1.260 out-of-hospital cardiac arrests, demonstrated no benefit to interrupting chest compressions to check the rhythm right after defibrillation.

Finally, with regards to the return of spontaneous circulation, two observational studies that included 2,969 out-of-hospital cardiac arrests showed harmful effects when chest compressions were interrupted immediately after shock delivery. Additionally, data from three randomised controlled trials, looking specifically at chest compression fraction, demonstrated harmful effects when chest compressions were interrupted to check the rhythm right after shock delivery. The trials included 1,412 out-of-hospital cardiac arrests.
 

Dispatch diagnosis of cardiac arrest

For this topic, we used the adult Basic Life Support, 2020 International Consensus on CPR from ILCOR (Olasveengen, 2020, S41) and the 2019 ILCOR systematic review of the dispatch diagnosis of cardiac arrest (Drennan et al., 2019).

The review looked at out-of-hospital cardiac arrests and assessed a variety of algorithms and criteria used by dispatch centres to identify potential life-threatening events (such as cardiac arrest) to triage emergency responders to the scene appropriately. Forty-six observational studies with 84,534 adult out-of-hospital cardiac arrests demonstrated the following results:

  • Dispatchers correctly identified cardiac arrest with a sensitivity of 0.79 (0.69–0.83).
  • Dispatchers incorrectly diagnosed the absence of cardiac arrest when the person was experiencing it (the critical outcome of a false negative) at 0.21 (0.17–0.32).

Twelve observational studies involving 789,004 out-of-hospital cardiac arrests showed the following results:

  • Dispatchers correctly identified the absence of cardiac arrest with a specificity of 0.99 (0.93–1.00).
  • Dispatchers incorrectly diagnosed cardiac arrest when the person was not experiencing it (false positive) at a rate of 0.01 (0.01–0.07).
Dispatcher-assisted CPR

We used one systematic review (Nikolaou-2019-82), one evidence summary from ILCOR in 2019 to look at the topic of dispatcher-assisted CPR (Soar-2019-e826) and the adult basic life support, 2020 international consensus on CPR from ILCOR (Olasveengen, 2020, S41).

When comparing the difference between a dispatcher assisting with CPR and not assisting, evidence suggested that if the dispatcher offered assistance over the phone, survival and survival with a favourable neurological outcome at hospital discharge, and one month after cardiac arrest, all increased. The review also showed that there was a correlation between the 21 systems offering dispatcher-assisted CPR and a sustained return of spontaneous circulation. However, there was no association with increased survival to hospital admission compared to systems without dispatcher-assisted CPR.

When comparing the outcomes in cardiac arrests outside of a hospital setting, people who received dispatcher-assisted CPR from a bystander include improvements in:

  • survival with a favourable neurological function, and survival in general, at hospital discharge and one month later, and
  • a greater likelihood of a return of spontaneous circulation.

These improvements were more likely to occur when bystanders received assistance from dispatchers to perform CPR than when no bystander CPR occurred.

The above findings were inconsistent when compared with instances when bystanders performed CPR with the assistance of a dispatcher versus when they performed CPR without assistance. The people receiving bystander CPR with dispatcher assistance were more likely to experience a return of spontaneous circulation upon hospital arrival than when bystanders did not have dispatcher assistance. This result suggests that dispatcher-assisted CPR could be as effective as unassisted CPR.

Feedback for CPR quality

CPR feedback or prompt devices are used to improve CPR quality, as ROSC, and survival from cardiac arrest. Feedback devices can measure various aspects of CPR mechanics, including ventilation rate, chest compression quality or measures of flow time (CPR fraction, etc.). These data can be used by the provider in real-time (audible or visual metronomes, voice or visual prompts or alarm) or as a summary report at the end of a resuscitation (numeric displays, waveforms, percentage).

Three real-time CPR guidance devices were identified in studies: digital audio-visual feedback, audio and tactile “clicker” feedback for chest compression depth and release and metronome guidance for chest compression rate. Nevertheless, due to heterogeneity across studies, it was not possible to make a metanalysis.
 

Education review

59 papers were identified through our search strategy as having insights to support adults learning CPR. Many supported insights covered elsewhere in these Guidelines concerning educational approaches and learning methodologies, but the evidence set out below indicates issues most specific to CPR.

Adaptation and prioritisation
  • Papalexopoulou et al., 2014; Sopka et al, 2013, identify the need for adaptation of educational tools (e.g. manikins and defibrillators), locations (e.g., waterfront scenarios for lifeguards) and methods to make them accessible and appropriate for learners’ needs and abilities.
  • Tweed and Wilson, 1977 advocate first aid education providers to prioritise training community members most likely to encounter cardiac arrest emergencies in CPR such as medics, police officers, firefighters and lifeguards. They suggest that these groups, given their status and role in the community, might make effective educators for the general public.
  • Huang et al. 2016 identify people with family members who are at high risk of cardiac arrest due to illness as being more motivated to learn first aid (see also Motivation to learn).
Barriers and challenges to learning
  • Some bystanders have concerns about disease exposure and transmission through standard CPR, which has caused a significant decrease in their willingness to provide it to both strangers and family members. Compression-only CPR is the preferred method (Cheng-Yu et al., 2016; Jelinek et al., 2001; Lam et al., 2007; Pei-Chuan Huang et al., 2019).
  • For practical CPR courses, there is limited evidence to demonstrate that female-only learner groups are beneficial to female learners, but there is evidence to support that males are more likely to learn in mixed groups (Sopka et al., 2013).
Enhanced scenario-based learning
  • Massive multiplayer virtual worlds allow learners to play a role and experience “real-life” scenarios and environments in which to practise their CPR skills. (Creutzfeldt et al., 2013). (See also Gamification, and Online learning for adults.)
Dispatcher assisted CPR
  • There is limited evidence in favour of the efficacy of dispatchers providing instructions to lay responders in giving CPR. Providing CPR instructions using video-assisted technology does not significantly improve the overall quality of bystander CPR compressions or rescue breaths (Bolle et al., 2009). However, in a study by Bolle et al. (2011) participants noted that video-equipped mobile phones should be utilised instead of audio-only phones during a medical emergency.  Given the fast-emerging technology associated with smartphones, we identify this as a gap in evidence in need of further exploration.
  • Dispatchers who communicate using video-assisted emergency calls may need more training for this tool to be effective and widespread within CPR education (Bolle et al., 2009). Bang et al. (2000) suggest that dispatchers with further training (e.g. technical and emotional) are more effective.

References

Systematic reviews

Berdowski, J., Berg, R. A., Tijssen, J. G. P., & Koster, R. W. (2010). Global incidences of out-of-hospital cardiac arrest and survival rates: Systematic review of 67 prospective studies. Resuscitation, 81(11), 1479–1487.
http://doi.org/10.1016/j.resuscitation.2010.08.006

Considine, J., Gazmuri, R. J., Perkins, G. D., Kudenchuk, P. J., Olasveengen, T. M., Vaillancourt, C., et al. (2019). Chest compression components (rate, depth, chest wall recoil and leaning): A scoping review. Resuscitation,
http://doi.org/10.1016/j.resuscitation.2019.08.042

Considine, J., Mancini, M.E., Morley, P., Avis, S., Brooks, S., Castren, M., Chung, S., … Olasveengen, T.M. (2019). Starting CPR (ABC vs. CAB) for Cardiac Arrest in Adults and Children Consensus on Science with Treatment Recommendations [Internet]. International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force. Available from: http://ilcor.org

Drennan, I. R., Geri, G., Couper K, Brooks, S, Kudenchuk, P. J., Pellegrino, J, Schexnayder, S, … Morley, P. T. (2019). Criteria to diagnose cardiac arrest in dispatch centres Consensus on Science with Treatment Recommendations [Internet]. International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force. Available from: http://ilcor.org
https://costr.ilcor.org/document/dispatch-diagnosis-of-cardiac-arrest-systematic-review)

Koster, R. W., Sayre, M. R., Botha, M., Cave, D. M., Cudnik, M. T., Handley, A. J., … & Morley, P. T. (2010). Part 5: Adult basic life support: 2010 International consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations. Resuscitation, 81(1), e48-e70.
http://doi.org/10.1016/j.resuscitation.2010.08.005

Nikolaou, N., Dainty, K. N., Couper, K., Morley, P., Tijssen, J., …Vaillancourt, C. (2019). A systematic review and meta-analysis of the effect of dispatcher-assisted CPR on outcomes from sudden cardiac arrest in adults and children. Resuscitation, 138, 82–105.
http://doi.org/10.1016/j.resuscitation.2019.02.035

Olasveengen, T. M., de Caen, A. R., Mancini, M. E., Maconochie, I. K., Aickin, R., … Atkins, D. L. (2017). 2017 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations Summary. Circulation, 136(23), III–5–17.
http://doi.org/10.1161/CIR.0000000000000541

Perkins, G. D., Travers, A. H., Berg, R. A., Castren, M., Considine, J., Escalante, R., et al. (2015). Part 3: Adult basic life support and automated external defibrillation: 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations. Resuscitation, 95, e43–69.
http://doi.org/10.1016/j.resuscitation.2015.07.041

Ristagno G, Olasveengen TM, Mancini MB, Avis S, Brooks S, Castren M, Chung S, Considine J, Kudenchuk P, Perkins G, Semeraro F, Smyth M. (2019). Rhythm check timing Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force, Dec 28th. Available from: https://costr.ilcor.org/document/rhythm-check-timing-tfsr-costr

Soar, J., Maconochie, I., Wyckoff, M. H., Olasveengen, T. M., Singletary, E. M., Greif, R., et al. (2019). 2019 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces. Circulation, CIR0000000000000734.
http://doi.org/10.1161/CIR.0000000000000734

Svavarsdottir H, Olasveengen TM, Mancini MB, Avis S, Brooks S, Castren M, Chung S, … Morley PT. (2019). Harm from CPR to Victims Not in Cardiac Arrest Consensus on Science with Treatment Recommendations. International Liaison Committee on Resuscitation (ILCOR) Basic Life Support Task Force. Available from: http://ilcor.org

Travers, A. H., Perkins, G. D., Berg, R. A., Castren, M., Considine, J., Escalante, R., et al. (2015). Part 3: Adult Basic Life Support and Automated External Defibrillation. Circulation, 132(16 suppl 1), S51–S83.
http://doi.org/10.1161/CIR.0000000000000272

Zhan, L., Yang, L. J., Huang, Y., He, Q., & Liu, G. J. (2017). Continuous chest compression versus interrupted chest compression for cardiopulmonary resuscitation of non-asphyxial out-of-hospital cardiac arrest. Cochrane Database of Systematic Reviews, 25(23), 1546–48.
http://doi.org/10.1002/14651858.CD010134.pub2

Non-systematic reviews

Bobrow, B. J., Spaite, D. W., Berg, R. A., Stolz, U., Sanders, A. B., Kern, K. B., et al. (2010). Chest compressiononly CPR by lay rescuers and survival from out-of-hospital cardiac arrest. JAMA: the Journal of the American Medical Association, 304(13), 1447–1454.
http://doi.org/10.1001/jama.2010.1392

Jiang, C., Jiang, S., Zhao, Y., Xu, B., & Zhou, X. L. (2015). Dominant hand position improves the quality of external chest compression: a manikin study based on 2010 CPR guidelines. The Journal of Emergency Medicine, 48(4), 436-444.
DOI: 10.1016/j.jemermed.2014.12.034

Kazaure, H. S., Roman, S. A., & Sosa, J. A. (2013). Epidemiology and outcomes of in-hospital cardiopulmonary resuscitation in the United States, 2000-2009. Resuscitation, 84(9), 1255–1260.
http://doi.org/10.1016/j.resuscitation.2013.02.021

Wang, J., Tang, C., Zhang, L., Gong, Y., Yin, C., & Li, Y. (2015). Compressing with dominant hand improves the quality of manual chest compressions for rescuers who performed suboptimal CPR in manikins. American Journal of Emergency Medicine, 33(7), 931–936.
http://doi.org/10.1016/j.ajem.2015.04.007

Education references

A., Herlitz, J., & Holmberg, S. (2000). Possibilities of Implementing Dispatcher-Assisted Cardiopulmonary Resuscitation in the Community: An Evaluation of 99 Consecutive Out-of-Hospital Cardiac Arrests. Resuscitation, 44(1), 19-26.

Bolle, S., Johnsen, E., & Gilbert, M. (2011). Video Calls for Dispatcher-Assisted Cardiopulmonary Resuscitation can Improve the Confidence of Lay Rescuers-Surveys After Simulated Cardiac Arrest. Journal of Telemedicine and Telecare, 17(1), 88-92.

Bolle, S., Scholl, J., & Gilbert, M. (2009). Can Video Mobile Phones Improve CPR Quality When Used for Dispatcher Assistance During Simulated Cardiac Arrest? Acta Anaesthesiol Scandinavica, 53(1), 116-120.

Cheng-Yu, C., Yi-Ming, W., Shou-Chien, H., & Chung-Hsien, C. (2016). Effect of Population-Based Training Programs on Bystander Willingness to Perform Cardiopulmonary Resuscitation. Signa Vitae-A Journal in Intensive Care and Emergency Medicine, 12(1), 63-69.

Creutzfeldt, J., Hedman, L., Heinrichs, L., Youngblood, P., & Fellander-Tsai, L. (2013). Cardiopulmonary Resuscitation Training in High School Using Avatars in Virtual Worlds: An International Feasibility Study. Journal of Medical Internet Research, 15(1), 1-14.

Huang, Q., Hu, C., & Mao, J. (2016). Are Chinese students willing to learn and perform bystander cardiopulmonary resuscitation? Journal of Emergency Medicine, 51(6), 712–720.
DOI: 10.1016/j.jemermed.2016.02.033

Jelinek, G., Gennat, H., Celenza, T., O’Brien, D., Jacobs, I., & Lynch, D. (2001). Community Attitudes Towards Performing Cardiopulmonary Resuscitation in Western Australia. Resuscitation, 51(3), 239-246.

Lam, K.-K., Lau, F.-L., Chan, W.-K., & Wong, W.-N. (2007). Effect of Severe Acute Respiratory Syndrome on Bystander Willingness to Perform Cardiopulmonary Resuscitation (CPR)-Is Compression-Only Preferred to Standard CPR? Prehospital and Disaster Medicine, 22(4), 325-329.

Papalexopoulou, K., Chalkias, A., Dontas, I., Pliatsika, P., Giannakakos, C., Papapanagiotou, P., … Xanthos, T. (2014). Education and Age Affect Skill Acquisition and Retention in Lay Rescuers After a European Resuscitation Council CPR/AED Course. Heart & Lung, 43(1), 66-71.

Pei-Chuan Huang, E., Chiang, W., Hsieh, M., Wang, H., Chong, K., Lin, C., . . . Huei-Ming Ma, M. (2019). Public Knowledge, Attitudes and Willingness Regarding Bystander Pulmonary Resuscitation: A Nationwide Survey in Taiwan. Journal of Formosan Medical Association, 118(2), 572-581.

Plant, N., & Taylor, K. (2013). How best to teach CPR to schoolchildren: a systematic review. Resuscitation, 84(4), 415-421.

Sopka, S., Biermann, H., Rossaint, R., Rex, S., Jager, M., Skorning, M., . . . Beckers, S. (2013). Resuscitation Training in Small-Group Setting – Gender Matters. Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine, 21(30), 2-10.

Tweed, W., & Wilson, E. (1977). Heart-Alert: Emergency Resuscitation Training in the Community. Canadian Medical Association, 117(22), 1399-1403.

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