Selasa, 15 Juli 2008

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



References
1. Recommended guidelines for uniform reporting of data from out-of-hospital cardiac arrest: the ‘Utstein style’. Prepared by a Task Force of Representatives from the European Resuscitation Council, American Heart Association. Heart and Stroke Foundation of Canada, Australian Resuscitation Council. Resuscitation 1991;22:1—26.

2. Sans S, Kesteloot H, Kromhout D. The burden of cardiovascular diseases mortality in Europe. Task Force of the European Society of Cardiology on Cardiovascular Mortality
and Morbidity Statistics in Europe. Eur Heart J 1997;18:1231—48.

3. Cobb LA, Fahrenbruch CE, Olsufka M, Copass MK. Changing incidence of out-of-hospital ventricular fibrillation, 1980—2000. JAMA 2002;288:3008—13.

4. Rea TD, Eisenberg MS, Sinibaldi G, White RD. Incidence of EMS-treated out-of-hospital cardiac arrest in the United States. Resuscitation 2004;63:17—24.

5. Vaillancourt C, Stiell IG. Cardiac arrest care and emergency medical services in Canada. Can J Cardiol 2004;20:1081—90.

6. Waalewijn RA, de Vos R, Koster RW. Out-of-hospital cardiac arrests in Amsterdam and its surrounding areas: results from the Amsterdam resuscitation study (ARREST) in ‘Utstein’ style. Resuscitation 1998;38:157—67.

7. Cummins R, Thies W. Automated external defibrillators and the Advanced Cardiac Life Support Program: a new initiative from the American Heart Association. Am J Emerg Med 1991;9:91—3.

8. Waalewijn RA, Nijpels MA, Tijssen JG, Koster RW. Prevention of deterioration of ventricular fibrillation by basic life support during out-of-hospital cardiac arrest. Resuscitation 2002;54:31—6.

9. Page S, Meerabeau L. Achieving change through reflective practice: closing the loop. Nurs Educ Today 2000;20:365—72.

10. Larsen MP, Eisenberg MS, Cummins RO, Hallstrom AP. Predicting survival from out-of-hospital cardiac arrest: a graphic model. Ann Emerg Med 1993;22:1652—8.

11. Cummins RO, Ornato JP, Thies WH, Pepe PE. Improving survival from sudden cardiac arrest: the ‘‘chain of survival’’ concept. A statement for health professionals from
the Advanced Cardiac Life Support Subcommittee and the Emergency Cardiac Care Committee, American Heart Association. Circulation 1991;83:1832—47.

12. Calle PA, Lagaert L, Vanhaute O, Buylaert WA. Do victims of an out-of-hospital cardiac arrest benefit from a training program for emergency medical dispatchers? Resuscitation 1997;35:213—8.

13. Curka PA, Pepe PE, Ginger VF, Sherrard RC, Ivy MV, Zachariah BS. Emergency medical services priority dispatch. Ann Emerg Med 1993;22:1688—95.

14. Valenzuela TD, Roe DJ, Cretin S, Spaite DW, Larsen MP. Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model. Circulation
1997;96:3308—13.

15. Holmberg M, Holmberg S, Herlitz J. Factors modifying the effect of bystander cardiopulmonary resuscitation on survival in out-of-hospital cardiac arrest patients in Sweden. Eur Heart J 2001;22:511—9.

16. Holmberg M, Holmberg S, Herlitz J, Gardelov B. Survival after cardiac arrest outside hospital in Sweden. Swedish Cardiac Arrest Registry. Resuscitation 1998;36:29—36.

17. Waalewijn RA, De Vos R, Tijssen JGP, Koster RW. Survival models for out-of-hospital cardiopulmonary resuscitation from the perspectives of the bystander, the first responder, and the paramedic. Resuscitation 2001;51:113—22.

18. Weaver WD, Hill D, Fahrenbruch CE, et al. Use of the automatic external defibrillator in the management of out-ofhospital cardiac arrest. N Engl J Med 1988;319:661—6.

19. Auble TE, Menegazzi JJ, Paris PM. Effect of out-ofhospital defibrillation by basic life support providers on cardiac arrest mortality: a metaanalysis. Ann Emerg Med 1995;25:642—58.

20. Stiell IG, Wells GA, DeMaio VJ, et al. Modifiable factors associated with improved cardiac arrest survival in a multicenter basic life support/defibrillation system: OPALS European Resuscitation Council Guidelines for Resuscitation 2005 S21 Study Phase I results. Ontario Prehospital Advanced Life Support. Ann Emerg Med 1999;33:44—50.

21. Stiell IG, Wells GA, Field BJ, et al. Improved out-of-hospital cardiac arrest survival through the inexpensive optimization of an existing defibrillation program: OPALS study
phase II. Ontario Prehospital Advanced Life Support. JAMA 1999;281:1175—81.

22. Caffrey S. Feasibility of public access to defibrillation. Curr Opin Crit Care 2002;8:195—8.

23. O’Rourke MF, Donaldson E, Geddes JS. An airline cardiac arrest program. Circulation 1997;96:2849—53.

24. Page RL, Hamdan MH, McKenas DK. Defibrillation aboard a commercial aircraft. Circulation 1998;97:1429—30.

25. Valenzuela TD, Roe DJ, Nichol G, Clark LL, Spaite DW, Hardman RG. Outcomes of rapid defibrillation by security officers after cardiac arrest in casinos. N Engl J Med 2000;343:1206—9.

26. Langhelle A, Nolan JP, Herlitz J, et al. Recommended guidelines for reviewing, reporting, and conducting research on post-resuscitation care: the Utstein style. Resuscitation 2005;66:271—83.

27. van Alem AP, Vrenken RH, de Vos R, Tijssen JG, Koster RW. Use of automated external defibrillator by first responders in out of hospital cardiac arrest: prospective controlled trial. BMJ 2003;327:1312—7.

28. Cobb LA, Fahrenbruch CE, Walsh TR, et al. Influence of cardiopulmonary resuscitation prior to defibrillation in patients with out-of-hospital ventricular fibrillation. JAMA 1999;281:1182—8.
29. Wik L, Myklebust H, Auestad BH, Steen PA. Retention of basic life support skills 6 months after training with an automated voice advisory manikin system without instructor involvement. Resuscitation 2002;52:273—9.

30. White RD, Russell JK. Refibrillation, resuscitation and survival in out-of-hospital sudden cardiac arrest victims treated with biphasic automated external defibrillators. Resuscitation 2002;55:17—23.

31. Kerber RE, Becker LB, Bourland JD, et al. Automatic external defibrillators for public access defibrillation: recommendations for specifying and reporting arrhythmia analysis
algorithm performance, incorporating new waveforms, and enhancing safety. A statement for health professionals from the American Heart Association Task Force on Automatic External Defibrillation, Subcommittee on AED Safety and Efficacy. Circulation 1997;95:1677—82.

32. Holmberg M, Holmberg S, Herlitz J. Effect of bystander cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients in Sweden. Resuscitation 2000;47:59— 70.

33. Heilman KM, Muschenheim C. Primary cutaneous tuberculosis resulting from mouth-to-mouth respiration. N Engl J Med 1965;273:1035—6.

34. Christian MD, Loutfy M, McDonald LC, et al. Possible SARS coronavirus transmission during cardiopulmonary resuscitation. Emerg Infect Dis 2004;10:287—93.

35. Cydulka RK, Connor PJ, Myers TF, Pavza G, Parker M. Prevention of oral bacterial flora transmission by using mouth-to-mask ventilation during CPR. J Emerg Med 1991;9:317—21.

36. Blenkharn JI, Buckingham SE, Zideman DA. Prevention of transmission of infection during mouth-to-mouth resuscitation. Resuscitation 1990;19:151—7.

37. Aprahamian C, Thompson BM, Finger WA, Darin JC. Experimental cervical spine injury model: evaluation of airway management and splinting techniques. Ann Emerg Med 1984;13:584—7.

38. Bahr J, Klingler H, Panzer W, Rode H, Kettler D. Skills of lay people in checking the carotid pulse. Resuscitation 1997;35:23—6.

39. Ruppert M, Reith MW, Widmann JH, et al. Checking for breathing: evaluation of the diagnostic capability of emergency medical services personnel, physicians, medical students, and medical laypersons. Ann Emerg Med 1999;34:720—9.

40. Perkins GD, Stephenson B, Hulme J, Monsieurs KG. Birmingham assessment of breathing study (BABS). Resuscitation 2005;64:109—13.

41. Domeier RM, Evans RW, Swor RA, Rivera-Rivera EJ, Frederiksen SM. Prospective validation of out-of-hospital spinal clearance criteria: a preliminary report. Acad Emerg Med 1997;4:643—6.

42. Hauff SR, Rea TD, Culley LL, Kerry F, Becker L, Eisenberg MS. Factors impeding dispatcher-assisted telephone cardiopulmonary resuscitation. Ann Emerg Med 2003;42:731—7.

43. Clark JJ, Larsen MP, Culley LL, Graves JR, Eisenberg MS. Incidence of agonal respirations in sudden cardiac arrest. Ann Emerg Med 1992;21:1464—7.

44. Kern KB, Hilwig RW, Berg RA, Sanders AB, Ewy GA. Importance of continuous chest compressions during cardiopulmonary resuscitation: improved outcome during a simulated single lay-rescuer scenario. Circulation 2002;105:645—9.

45. Handley JA, Handley AJ. Four-step CPR—–improving skill retention. Resuscitation 1998;36:3—8.

46. Ornato JP, Hallagan LF, McMahan SB, Peeples EH, Rostafinski AG. Attitudes of BCLS instructors about mouth-to-mouth resuscitation during the AIDS epidemic. Ann Emerg Med 1990;19:151—6.

47. Brenner BE, Van DC, Cheng D, Lazar EJ. Determinants of reluctance to perform CPR among residents and applicants: the impact of experience on helping behavior. Resuscitation 1997;35:203—11.

48. Hew P, Brenner B, Kaufman J. Reluctance of paramedics and emergency medical technicians to perform mouth-tomouth resuscitation. J Emerg Med 1997;15:279—84.

49. Baskett P, Nolan J, Parr M. Tidal volumes which are perceived to be adequate for resuscitation. Resuscitation 1996;31:231—4.

50. Aufderheide TP, Sigurdsson G, Pirrallo RG, et al. Hyperventilation-induced hypotension during cardiopulmonary resuscitation. Circulation 2004;109:1960—5.

51. Wenzel V, Idris AH, Banner MJ, Kubilis PS, Williams JLJ. Influence of tidal volume on the distribution of gas between the lungs and stomach in the nonintubated patient receiving positive-pressure ventilation. Crit Care Med 1998;26:364—8.

52. Idris A, Gabrielli A, Caruso L. Smaller tidal volume is safe and effective for bag-valve-ventilation, but not for mouthto- mouth ventilation: an animal model for basic life support. Circulation 1999;100(Suppl. I):I-644.

53. Idris A, Wenzel V, Banner MJ, Melker RJ. Smaller tidal volumes minimize gastric inflation during CPR with an unprotected airway. Circulation 1995;92(Suppl.):I-759.

54. Dorph E, Wik L, Steen PA. Arterial blood gases with 700 ml tidal volumes during out-of-hospital CPR. Resuscitation 2004;61:23—7.

55. Winkler M, Mauritz W, Hackl W, et al. Effects of half the tidal volume during cardiopulmonary resuscitation on acidbase balance and haemodynamics in pigs. Eur J Emerg Med 1998;5:201—6.

56. Eftestol T, Sunde K, Steen PA. Effects of interrupting precordial compressions on the calculated probability of S22 A.J. Handley et al. defibrillation success during out-of-hospital cardiac arrest. Circulation 2002;105:2270—3.

57. Ruben H. The immediate treatment of respiratory failure. Br J Anaesth 1964;36:542—9.

58. Elam JO. Bag-valve-mask O2 ventilation. In: Safar P, Elam JO, editors. Advances in cardiopulmonary resuscitation: the Wolf Creek Conference on Cardiopulmonary Resuscitation. New York, NY: Springer-Verlag, Inc.; 1977. p. 73—9.

59. Dailey RH. The airway: emergency management. St. Louis, MO: Mosby Year Book; 1992.

60. Paradis NA, Martin GB, Goetting MG, et al. Simultaneous aortic, jugular bulb, and right atrial pressures during cardiopulmonary resuscitation in humans. Insights into mechanisms. Circulation 1989;80:361—8.

61. Wik L, Hansen TB, Fylling F, et al. Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrillation: a randomized trial. JAMA 2003;289:1389—95.

62. International Liaison Committee on Resuscitation. International consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations. Resuscitation 2005:67.

63. Handley AJ. Teaching hand placement for chest compression—–a simpler technique. Resuscitation 2002;53:29—36.

64. Yu T, Weil MH, Tang W, et al. Adverse outcomes of interrupted precordial compression during automated defibrillation. Circulation 2002;106:368—72.

65. Swenson RD, Weaver WD, Niskanen RA, Martin J, Dahlberg S. Hemodynamics in humans during conventional and experimental methods of cardiopulmonary resuscitation. Circulation 1988;78:630—9.

66. Kern KB, Sanders AB, Raife J, Milander MM, Otto CW, Ewy GA. A study of chest compression rates during cardiopulmonary resuscitation in humans: the importance
of rate-directed chest compressions. Arch Intern Med 1992;152:145—9.

67. Abella BS, Alvarado JP, Myklebust H, et al. Quality of cardiopulmonary resuscitation during in-hospital cardiac arrest. JAMA 2005;293:305—10.

68. Wik L, Kramer-Johansen J, Myklebust H, et al. Quality of cardiopulmonary resuscitation during out-of-hospital cardiac arrest. JAMA 2005;293:299—304.

69. Aufderheide TP, Pirrallo RG, Yannopoulos D, et al. Incomplete chest wall decompression: a clinical evaluation of CPR performance by EMS personnel and assessment of alternative manual chest compression—decompression techniques. Resuscitation 2005;64:353—62.

70. Yannopoulos D, McKnite S, Aufderheide TP, et al. Effects of incomplete chest wall decompression during cardiopulmonary resuscitation on coronary and cerebral perfusion pressures in a porcine model of cardiac arrest. Resuscitation 2005;64:363—72.

71. Ochoa FJ, Ramalle-Gomara E, Carpintero JM, Garcia A, Saralegui I. Competence of health professionals to check the carotid pulse. Resuscitation 1998;37:173—5.

72. Handley AJ, Monsieurs KG, Bossaert LL. European Resuscitation Council Guidelines 2000 for Adult Basic Life Support. A statement from the Basic Life Support and Automated External Defibrillation Working Group(1) and approved by the Executive Committee of the European Resuscitation Council. Resuscitation 2001;48:199—205.

73. Sanders AB, Kern KB, Berg RA, Hilwig RW, Heidenrich J, Ewy GA. Survival and neurologic outcome after cardiopulmonary resuscitation with four different chest compression-ventilation ratios. Ann Emerg Med 2002;40:553—62.

74. Dorph E, Wik L, Stromme TA, Eriksen M, Steen PA. Quality of CPR with three different ventilation:compression ratios. Resuscitation 2003;58:193—201.

75. Dorph E, Wik L, Stromme TA, Eriksen M, Steen PA. Oxygen delivery and return of spontaneous circulation with ventilation: compression ratio 2:30 versus chest compressions only CPR in pigs. Resuscitation 2004;60:309—18.

76. Babbs CF, Kern KB. Optimum compression to ventilation ratios in CPR under realistic, practical conditions: a physiological and mathematical analysis. Resuscitation
2002;54:147—57.

77. Fenici P, Idris AH, Lurie KG, Ursella S, Gabrielli A. What is the optimal chest compression—ventilation ratio? Curr Opin Crit Care 2005;11:204—11.

78. Aufderheide TP, Lurie KG. Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Crit Care Med 2004;32:S345—51.

79. Chandra NC, Gruben KG, Tsitlik JE, et al. Observations of ventilation during resuscitation in a canine model. Circulation 1994;90:3070—5.

80. Becker LB, Berg RA, Pepe PE, et al. A reappraisal of mouthto- mouth ventilation during bystander-initiated cardiopulmonary resuscitation. A statement for healthcare professionals from the Ventilation Working Group of the Basic Life Support and Pediatric Life Support Subcommittees, American Heart Association. Resuscitation 1997;35:189—201.

81. Berg RA, Kern KB, Hilwig RW, et al. Assisted ventilation does not improve outcome in a porcine model of singlerescuer bystander cardiopulmonary resuscitation. Circulation 1997;95:1635—41.

82. Berg RA, Kern KB, Hilwig RW, Ewy GA. Assisted ventilation during ‘bystander’ CPR in a swine acute myocardial infarction model does not improve outcome. Circulation 1997;96:4364—71.

83. Handley AJ, Handley JA. Performing chest compressions in a confined space. Resuscitation 2004;61:55—61.

84. Perkins GD, Stephenson BT, Smith CM, Gao F. A comparison between over-the-head and standard cardiopulmonary resuscitation. Resuscitation 2004;61:155—61.

85. Turner S, Turner I, Chapman D, et al. A comparative study of the 1992 and 1997 recovery positions for use in the UK. Resuscitation 1998;39:153—60.

86. Handley AJ. Recovery position. Resuscitation 1993;26:93—5.

87. Anonymous. Guidelines 2000 for cardiopulmonary resuscitation and emergency cardiovascular care—–an international consensus on science. Resuscitation 2000;46:1—447.