The respiratory system during resuscitation: a review of the history, riskof infection during assisted ventilation, respiratory mechanics, and ventilation strategies for patients with an unprotected airway

The fear of acquiring infectious diseases has resulted in reluctance among healthcare professionals and the lay public to perform mouth-to-mouth venti lation. However, the benefit of basic life support for a patient in cardiop ulmonary or respiratory arrest greatly outweighs the risk for secondary inf ection in the rescuer or the patient. The distribution of ventilation volum e between lungs and stomach in the unprotected airway depends on patient va riables such as lower oesophageal sphincter pressure, airway resistance and respiratory system compliance, and the technique applied while performing basic or advanced airway support, such as head position, inflation flow rat e and time, which determine upper airway pressure. The combination of these variables determines gas distribution between the lungs and the oesophagus and subsequently, the stomach. During bag-valve-mask ventilation of patien ts in respiratory or cardiac arrest with oxygen supplementation (greater th an or equal to 40% oxygen), a tidal volume of 6-7 mi kg(-1) (similar to 500 ml) given over 1-2 s until the chest rises is recommended. For bag-valve-m ask ventilation with room-air, a tidal volume of 10 ml kg(-1) (700-1000 ml) in an adult given over 2 s until the chest rises clearly is recommended. D uring mouth-to-mouth ventilation, a breath over 2 s sufficient to make the chest rise clearly (a tidal volume of similar to 10 mi kg(-1) similar to 70 0-1000 mi in an adult) is recommended. (C) 2001 Elsevier Science Ireland Lt d. All rights reserved.