Control of the airway and emergency ventilation has long been recognised as an essential part of life support since the pioneering work of Safar and his colleagues. Although there has recently been an attempt to reduce the importance of emergency ventilation in CPR (3) this has been vigorously refuted (4,5). In prehospital emergency care for trauma the value of airway management and effective ventilation hold an undisputed place in management in an area where much controversy exists concerning techniques of management.

In emergency medicine there are many conditions apart from cardiac arrest that affect breathing. There may be failure of the central control and the peripheral mechanism of breathing from a variety of traumatic, toxic and other pathological causes. Emergency ventilation with an increased inspired oxygen concentration is necessary to overcome the alterations in physiological dead space, lung compliance and resistance and diffusion that may result. The production of effective emergency ventilation may not always be straightforward. Unlike artificial ventilation in a hospital which is initiated in a controlled environment with detailed patient assessment and monitoring, emergency ventilation is usually carried out under difficult circumstances. There is often little detailed information about the patient’s respiratory status and the decision to ventilate is usually taken on clinical grounds.

Options for emergency ventilation depend on the equipment available and the skill and experience of the responders. Although bag – valve – mask (BVM) ventilation is a familiar concept and apparently effective in the controlled conditions of an operating theatre it presents difficulties in emergency and has been shown in experimental models to be less effective than automatic ventilation through a mask.Alternatives to the BVM include pressure controlled insufflators which have a number of limitations and gas – powered emergency ventilators, many of which now have demand valve technology included to be able to respond to the situation of partial respiratory failure.

Apart from specifying protocols for life support ILCOR is currently concerned with how much ventilation is necessary in emergency, particularly in CPR where reduction of the time spent on ventilation allows optimisation of circulatory support by chest compression. Although certain member organisations still favour high tidal volumes of 800 – 1000ml a new school has recommended consideration of a lower volume of 400ml with the same chest compression: ventilation (CV) ratios of 15:2 for single and 5:1 for two person CPR (6). The rationale for this change is that in cardiac arrest less carbon dioxide is being delivered to the lungs and therefore less ventilation is required during the early resuscitation stages. Prospective studies in this field however are difficult and there is relatively little data on which to build new protocols. It seems likely that revised CV ratios will be considered in the future but these will require a major reteaching programme for the general public who are involved with basic life support.

The strength of the ILCOR guidelines is that they provide a uniform basis for development and teaching of CPR procedures. ILCOR has reaffirmed the classical airway – breathing – circulation approach and placed emphasis on early airway and ventilation management. Through improved training emergency services may expand their airway and ventilation skills and options with the wide range of equipment suitable for emergency use that is now available in all parts of the world.

References

1 Handley AJ,Becker LB, Allen M et al. Single rescuer basic life support; an advisory statement from the BLS working group of ILCOR. Resuscitation 1997; 34(2): 101 – 8.

2 Kloeck W, Cummin R, Chamberlain D et al. The universal ALS algorithm: an advisory statement from the ALS working group of ILCOR. Resuscitation 1997; 34(2): 109 – 13.

3 Becker LB,Berg RA, Pepe LE et al. A reappraisal of mouth to mouth ventilation during bystander CPR. Circulation 1997; 96: 2112 – 12.

4 Safar P,Bircher N, Petto E et al. Letter to the editor. Resuscitation 1998; 36(3), 75 – 80.

5 Dick WF, Brambrink AM, Kern T. 'Topless' cardiopulmonary resuscitation. Should heart – lung resuscitation be performed without artificial resuscitation?