Ventilation in the unprotected airway

The fear of acquiring infectious diseases has resulted in a reluctance to perform mouth-to-mouth ventilation among healthcare professionals and the lay public. However, the benefit of initiating lifesaving resuscitation in a patient in cardiopulmonary and/or respiratory arrest greatly outweighs the risk for secondary infection in the rescuer or the patient. The distribution of ventilation volume between lungs and stomach in the unprotected airway depends on patient variables (such as lower oesophageal sphincter pressure, airway resistance and respiratory system compliance) and the technique applied by the healthcare professional while performing basic or advanced airway support (such as head position, inspiratory flow rate and time and, especially, upper airway pressure). The combination of these variables determines the gas distribution between the lungs and the oesophagus and, subsequently, the stomach. During bag-valve-mask ventilation of a patient in respiratory or cardiac arrest with oxygen supplementation (≥40% oxygen), a tidal volume of 6-7 ml/kg (~500 ml) given over 1-2 seconds until the chest rises is recommended. For bag-valve-mask ventilation with room-air, a tidal volume of 10 ml/kg (700-1000 ml) in an adult given over 2 seconds until the chest rises is recommended. During mouth-to-mouth ventilation, a breath over 2 seconds sufficient to make the chest rise clearly (tidal volume of ~10 ml/kg (~700-1000 ml in an adult) is recommended.