ADULT BASIC LIFE SUPPORT

European Resuscitation Council Guidelines for Resuscitation 2005

Adult basic life support

Basic life support (BLS) refers to maintaining airway patency and supporting breathing and the circulation, without the use of equipment other than a protective device. This section contains the guidelines for adult BLS by lay rescuers and for the use of an automated external defibrillator (AED). It also includes recognition of sudden cardiac arrest, the recovery position and management of choking (foreign-body airway obstruction).

Introduction
Sudden cardiac arrest (SCA) is a leading cause of death in Europe, affecting about 700,000 individuals a year. At the time of the first heart rhythm analysis, about 40% of SCA victims have ventricular fibrillation (VF). It is likely that many more victims have VF or rapid ventricular tachycardia (VT) at the time of collapse but, by the time the first ECG is recorded, their rhythm has deteriorated to asystole. VF is characterized by chaotic, rapid depolarisation and repolarisation. The heart loses its coordinated function and stops pumping blood effectively. Many victims of SCA can survive if bystanders act immediately while VF is still present, but successful resuscitation is unlikely once the rhythm has deteriorated to asystole. The optimum treatment for VF cardiac arrest is immediate bystander CPR (combined chest compression and rescue breathing) plus electrical defibrillation. The predominant mechanism of cardiac arrest in victims of trauma, drug overdose, drowning, and in many children is asphyxia; rescue breaths are critical for resuscitation of these victims. The following concept of the Chain of Survival summarises the vital steps needed for successful resuscitation (Figure 1.1). Most of these links are relevant for victims of both VF and asphyxia arrest.
1. Early recognition of the emergency and calling for help: activate the emergency medical services (EMS) or local emergency response system, e.g. ‘‘phone 112’’. An early, effective response may prevent cardiac arrest.
2. Early bystander CPR: immediate CPR can double or triple survival from VF SCA.
3. Early defibrillation: CPR plus defibrillation within 3—5 min of collapse can produce survival rates as high as 49—75%. Each minute of delay in defibrillation reduces the probability of survival to discharge by 10—15%.
4. Early advanced life support and post resuscitation care: the quality of treatment during the post-resuscitation phase affects outcome.

In most communities, the time from EMS call to EMS arrival (response interval) is 8 min or longer. During this time the victim’s survival is dependent on early initiation by bystanders of the first three of the links of the Chain of Survival. Victims of cardiac arrest need immediate CPR. This provides a small but critical blood flow to the heart and brain. It also increases the likelihood that a defibrillatory shock will terminate VF and enable the heart to resume an effective rhythm and effective systemic perfusion. Chest compression is especially important if a shock cannot be delivered sooner than 4 or 5 min after collapse. Defibrillation interrupts the uncoordinated depolarization repolarisation process that occurs during VF. If the heart is still viable, its normal pacemakers then resume their function and produce an effective rhythm and resumption of circulation. In the first few minutes after successful defibrillation, the rhythm may be slow and ineffective; chest compressions may be needed until adequate cardiac function returns. Lay rescuers can be trained to use an automated external defibrillator (AED) to analyse the victim’s cardiac rhythm and deliver a shock if VF is present. An AED uses voice prompts to guide the rescuer. It analyses the ECG rhythm and informs the rescuer if a shock is needed. AEDs are extremely accurate and will deliver a shock only when VF (or its precursor, rapid ventricular tachycardia) is present. AED function and operation are discussed in Section 3. Several studies have shown the benefit on survival of immediate CPR, and the detrimental effect of delay before defibrillation. For every minute without CPR, survival from witnessed VF decreases by 7-10%. When bystander CPR is provided, the decline in survival is more gradual and averages 3 - 4% min−1. Overall, bystander CPR doubles or triples survival from witnessed cardiac arrest.

Adult BLS sequence
BLS consists of the following sequence of actions (Figure 2.1).
1. Make sure you, the victim and any bystanders are safe.
2. Check the victim for a response (Figure 2.2).
gently shake his shoulders and ask loudly: ‘‘Are you all right?’’

3a. if he responds
a. Leave him in the position in which you find him provided there is no further danger
b. Try to find out what is wrong with him and get help if needed
c. Reassess him regularly

Figure 2.2 Check the victim for a response. © 2005 European Resuscitation Council.

Figure 2.3 Shout for help. © 2005 European Resuscitation Council.

3b. if he does not respond
a. Shout for help (Figure 2.3)
b. Turn the victim onto his back and then open the airway using head tilt and chin lift (Figure 2.4)
1) place your hand on his forehead and gently tilt his head back keeping your thumb and index finger free to close his nose if rescue breathing is required (Figure 2.5)

Figure 2.4 Head tilt and chin lift. © 2005 European Resuscitation Council.

2) with your fingertips under the point of the victim’s chin, lift the chin to open the airway


Figure 2.5 Head tilt and chin lift in detail. © 2005 European Resuscitation Council.

4. Keeping the airway open, look, listen and feel for normal breathing (Figure 2.6).
a. Look for chest movement.
b. Listen at the victim’s mouth for breath sounds.
c. Feel for air on your cheek.

In the first few minutes after cardiac arrest, a victim may be barely breathing, or taking infrequent, noisy gasps. Do not confuse this with normal breathing. Look, listen, and feel for no more than 10 s to determine whether the victim is breathing normally. If you have any doubt whether breathing is normal, act as if it is not normal.

Figure 2.6 Look listen and feel for normal breathing. © 2005 European Resuscitation Council.




Figure 2.7 The recovery position. © 2005 European Resuscitation Council.


5a If he is breathing normally
a. turn him into the recovery position (see below) (Figure 2.7)
b. send or go for help/call for an ambulance
c. check for continued breathing


5b If he is not breathing normally
Send someone for help or, if you are on your own, leave the victim and alert the ambulance service; return and start chest compression as follows:
a. Kneel by the side of the victim
b. Place the heel of one hand in the centre of the victim’s chest (figure 2.8)
c. Place the heel of your other hand on top of the first hand (figure 2.9)
d. Interlock the fingers of your hands and ensure that pressure is not applied over the victim’s ribs (figure 2.10). Do not apply any pressure over the upper abdomen or the bottom end of the bony sternum (breastbone)
e. Position yourself vertically above the victim’s chest and, with your arms straight, press down on the sternum 4—5 cm (Figure 2.11)
f. after each compression, release all the pressure on the chest without losing contact between your hands and the sternum; repeat at a rate of about 100 min−1 (a little less than 2 compressions s−1)
g. compression and release should take equal amounts of time

6a Combine chest compression with rescue breaths.
a. After 30 compressions open the airway again using head tilt and chin lift (Figure 2.12).
b. Pinch the soft part of the nose closed, using the index finger and thumb of your hand on the forehead.
c. Allow the mouth to open, but maintain chin lift.
d. Take a normal breath and place your lips around his the mouth, making sure that you have a good seal.
e. Blow steadily into the mouth while watching for the chest to rise (Figure 2.13), taking
f. About 1 s as in normal breathing; this is an effective rescue breath.
g. Maintaining head tilt and chin lift, take your mouth away from the victim and watch for the chest to fall as air passes out (Figure 2.14).
h. Take another normal breath and blow into the victim’s mouth once more, to achieve a total of two effective rescue breaths. Then return your hands without delay to the correct position on the sternum and give a further 30 chest compressions.
i. Continue with chest compressions and rescue breaths in a ratio of 30:2.
j. Stop to recheck the victim only if he starts breathing normally; otherwise do not interrupt resuscitation.

If your initial rescue breath does not make the chest rise as in normal breathing, then before your next attempt:
a. Check the victim’s mouth and remove any obstruction
b. Recheck that there is adequate head tilt and chin lift
c. Do not attempt more than two breaths each time before returning to chest compressions If there is more than one rescuer present, another should take over CPR every 1—2 min to prevent fatigue. Ensure the minimum of delay during the changeover of rescuers.


Figure 2.8 Place the heel of one hand in the centre of the victim’s chest. © 2005 European Resuscitation Council.




Figure 2.9 Place the heel of your other hand on top of the first hand. © 2005 European Resuscitation Council.

Figure 2.10 Interlock the fingers of your hands. © 2005 European Resuscitation Council.

Figure 2.11 Press down on the sternum 4—5 cm. © 2005 European Resuscitation Council.





Figure 2.12 After 30 compressions open the airway again using head tilt and chin lift. © 2005 European Resuscitation Council.

6b Chest-compression-only CPR may be used as follows.
a. If you are not able or are unwilling to give rescue breaths, give chest compressions only.
b. If chest compressions only are given, these should be continuous, at a rate of 100 min−1.
c. Stop to recheck the victim only if he starts breathing normally; otherwise do not interrupt resuscitation.

7 Continue resuscitation until
a. Qualified help arrives and takes over
b. The victim starts breathing normally
c. You become exhausted


Figure 2.13 Blow steadily into his mouth whilst watching for his chest to rise. © 2005 European Resuscitation Council.

Risk to the rescuer
The safety of both rescuer and victim are paramount during a resuscitation attempt. There have been few incidents of rescuers suffering adverse effects from undertaking CPR, with only isolated reports of infections such as tuberculosis (TB) and severe acute respiratory distress syndrome (SARS). Transmission of HIV during CPR has never been reported. There have been no human studies to address the effectiveness of barrier devices during CPR; however, laboratory studies have shown that certain filters, or barrier devices with one-way valves, prevent oral bacterial transmission from the victim to the rescuer during mouth-to-mouth ventilation. Rescuers should take appropriate safety precautions where feasible, especially if the victim is known to have a serious infection, such as TB or SARS. During an outbreak of a highly infectious condition such as SARS, full protective precautions for the rescuer are essential.

Figure 2.14 Take your mouth away from the victim and watch for his chest to fall as air comes out. © 2005 European Resuscitation Council.

Opening the airway
The jaw thrust is not recommended for lay rescuers because it is difficult to learn and perform and may itself cause spinal movement. Therefore, the lay rescuer should open the airway using a head tilt-chin lift manoeuvre for both injured and noninjured victims.

Recognition of cardiorespiratory arrest
Checking the carotid pulse is an inaccurate method of confirming the presence or absence of circulation. However, there is no evidence that checking for movement, breathing or coughing (‘signs of a circulation’) is diagnostically superior. Healthcare professionals as well as lay rescuers have difficulty determining the presence or absence of adequate or normal breathing in unresponsive victims. This may be because the airway is not open or because the victim is making occasional (agonal) gasps. When bystanders are asked by ambulance dispatchers over the telephone if breathing is present, they often misinterpret agonal gasps as normal breathing. This erroneous information can result in the bystander withholding CPR from a cardiac arrest victim. Agonal gasps are present in up to 40% of cardiac arrest victims. Bystanders describe agonal gasps as barely breathing, heavy or laboured breathing, or noisy or gasping breathing. Laypeople should, therefore, be taught to begin CPR if the victim is unconscious (unresponsive) and not breathing normally. It should be emphasized during training that agonal gasps occur commonly in the first few minutes after SCA. They are an indication for starting CPR immediately and should not be confused with normal breathing.

Initial rescue breaths
During the first few min after non-asphyxial cardiac arrest the blood oxygen content remains high, and myocardial and cerebral oxygen delivery is limited more by the diminished cardiac output than a lack of oxygen in the lungs. Ventilation is, therefore, initially less important than chest compression. It is well recognised that skill acquisition and retention is aided by simplification of the BLS sequence of actions. It is also recognized that rescuers are frequently unwilling to carry out mouth-to-mouth ventilation for a variety of reasons, including fear of infection and distaste for the procedure. For these reasons, and to emphasise the priority of chest compressions, it is recommended
that in adults CPR should start with chest compression rather than initial ventilation.

Ventilation
During CPR the purpose of ventilation is to maintain adequate oxygenation. The optimal tidal volume, respiratory rate and inspired oxygen concentration to achieve this, however, are not fully known. The current recommendations are based on the following
evidence:
1. During CPR, blood flow to the lungs is substantially reduced, so an adequate ventilation perfusion ratio can be maintained with lower tidal volumes and respiratory rates than normal.
2. Not only is hyperventilation (too many breaths or too large a volume) unnecessary, but it is harmful because it increases intrathoracic pressure, thus decreasing venous return to the heart and diminishing cardiac output. Survival is consequently reduced.
3. When the airway is unprotected, a tidal volume of 1 l produces significantly more gastric distention than a tidal volume of 500 ml.
4. Low minute-ventilation (lower than normal tidal volume and respiratory rate) can maintain effective oxygenation and ventilation during CPR. During adult CPR, tidal volumes of approximately 500—600 ml (6—7 ml kg−1) should be adequate.
5. Interruptions in chest compression (for example to give rescue breaths) have a detrimental effect on survival. Giving rescue breaths over a shorter time will help to reduce the duration of essential interruptions.

The current recommendation is, therefore, for rescuers to give each rescue breath over about 1 s, with enough volume to make the victim’s chest rise, but to avoid rapid or forceful breaths This recommendation applies to all forms of ventilation during CPR, including mouth-to-mouth and bag valve- mask (BVM) with and without supplementary
oxygen. Mouth-to-nose ventilation is an effective alternative to mouth-to-mouth ventilation. It may be considered if the victim’s mouth is seriously injured or cannot be opened, the rescuer is assisting a victim in the water, or a mouth-to-mouth seal is difficult to achieve. There is no published evidence on the safety, effectiveness or feasibility of mouth to-tracheostomy ventilation, but it may be used for a victim with a tracheostomy tube or tracheal stoma who requires rescue breathing. To use bag-mask ventilation requires considerable practice and skill. The lone rescuer has to be able to open the airway with a jaw thrust while simultaneously holding the mask to the victim’s
face. It is a technique that is appropriate only for lay rescuers who work in highly specialized areas, such as where there is a risk of cyanide poisoning or exposure to other toxic agents. There are other specific circumstances in which nonhealthcare providers receive extended training in first aid which could include training, and retraining, in the use of bag-mask ventilation. The same strict training that applies to healthcare professionals should be followed.

Chest compression
Chest compressions produce blood flow by increasing the intrathoracic pressure and by directly compressing the heart. Although chest compressions performed properly can produce systolic arterial pressure peaks of 60—80 mmHg, diastolic pressure remains low and mean arterial pressure in the carotid artery seldom exceeds 40 mmHg. Chest compressions generate a small but critical amount of blood flow to the brain and myocardium and increase the likelihood that defibrillation will be successful. They are especially important if the first shock is delivered more than 5 min after collapse. Much of the information about the physiology of chest compression and the effects of varying the compression rate, compression-to-ventilation ratio and duty cycle (ratio of time chest is compressed to total time from one compression to the next) is derived from animal models. However, the conclusions of the 2005 Consensus Conference included the following:
(1) Each time compressions are resumed, the rescuer should place his hands without delay ‘‘in the centre of the chest’’.
(2) Compress the chest at a rate of about 100 min−1.
(3) Pay attention to achieving the full compression depth of 4—5 cm (for an adult).
(4) Allow the chest to recoil completely after each compression.
(5) Take approximately the same amount of time for compression and relaxation.
(6) Minimize interruptions in chest compression.
(7) Do not rely on a palpable carotid or femoral pulse as a gauge of effective arterial flow.

There is insufficient evidence to support a specific hand position for chest compression during CPR in adults. Previous guidelines have recommended a method of finding the middle of the lower half of the sternum by placing one finger on the lower end of the sternum and sliding the other hand down to it. It has been shown that for healthcare professionals the same hand position can be found more quickly if rescuers are taught to ‘‘place the heel of your hand in the centre of the chest with the other hand on top’’, provided the teaching includes a demonstration of placing the hands in the middle of the lower half of the sternum. It is reasonable to extend this to laypeople. Compression rate refers to the speed at which compressions are given, not the total number delivered in each minute. The number delivered is determined by the rate, but also by the number of interruptions to open the airway, deliver rescue breaths and allow AED analysis. In one out of- hospital study rescuers recorded compression rates of 100—120 min−1 but, the mean number of compressions was reduced to 64 min−1 by frequent interruptions.

Compression—ventilation ratio
Insufficient evidence from human outcome studies exists to support any given compression : ventilation ratio. Animal data support an increase in the ratio above 15:2. A mathematical model suggests that a ratio of 30:2 would provide the best compromise between blood flow and oxygen delivery. A ratio of 30 compressions to two ventilations is recommended for the single rescuer attempting resuscitation on an adult or child out of hospital. This should decrease the number of interruptions in compression, reduce the likelihood of hyperventilation, simplify instruction for teaching and improve skill retention.

Compression-only CPR
Healthcare professionals as well as lay rescuers admit to being reluctant to perform mouth-to mouth ventilation in unknown victims of cardiac arrest. Animal studies have shown that chest compression-only CPR may be as effective as combined ventilation and compression in the first few minutes after non-asphyxia arrest. In adults, the outcome of chest compression without ventilation is significantly better than the outcome of giving no CPR. If the airway is open, occasional gasps and passive chest recoil may provide some air exchange. A low minute-ventilation may be all that is necessary to maintain a normal ventilation perfusion ratio during CPR. Lay people should, therefore, be encouraged to perform compression-only CPR if they are unable or unwilling to provide rescue breaths, although combined chest compression and ventilation is the better method of CPR.

CPR in confined spaces
Over-the-head CPR for single rescuers and straddle CPR for two rescuers may be considered for resuscitation in confined spaces.

Recovery position
There are several variations of the recovery position, each with its own advantages. No single position is perfect for all victims. The position should be stable, near a true lateral position with the head dependent, and with no pressure on the chest to impair breathing. The ERC recommends the following sequence of actions to place a victim in the recovery position:
a. Remove the victim’s spectacles.
b. Kneel beside the victim and make sure that both legs are straight.
c. Place the arm nearest to you out at right angles to the body, elbow bent with the hand palm uppermost (Figure 2.15).
d. Bring the far arm across the chest, and hold the back of the hand against the victim’s cheek nearest to you (Figure 2.16).
e. With your other hand, grasp the far leg just above the knee and pull it up, keeping the foot on the ground (Figure 2.17).
f. Keeping his hand pressed against his cheek, pull on the far leg to roll the victim towards you onto his side.
g. Adjust the upper leg so that both hip and knee are bent at right angles.
h. Tilt the head back to make sure the airway remains open.
i. Adjust the hand under the cheek, if necessary, to keep the head tilted (Figure 2.18).
j. Check breathing regularly.

If the victim has to be kept in the recovery position for more than 30 min turn him to the opposite side to relieve the pressure on the lower arm.



Figure 2.15 Place the arm nearest to you out at right angles to his body, elbow bent with the hand palm uppermost. © 2005 European Resuscitation Council.



Figure 2.16 Bring the far arm across the chest, and hold the back of the hand against the victim’s cheek nearest to you. © 2005 European Resuscitation Council.

Figure 2.17 With your other hand, grasp the far leg just above the knee and pull it up, keeping the foot on the ground. © 2005 European Resuscitation Council.

Figure 2.18 The recovery position. © 2005 European Resuscitation Council.




RESOURCES:
European Resuscitation Council (ERC)
www.elsevier.com/locate/resuscitation



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