Organ Failure Classification

The review classified primary organ failure into upper airway obstruction, lower respiratory obstruction from bronchospasm, and cardiovascular failure. Upper airway obstruction causes acute asphyxia through oropharyngeal or laryngeal oedema. Lower airway obstruction causes respiratory failure mainly through bronchospasm and can lead to secondary hypoxaemic cardiac arrest. Cardiovascular failure occurs through vasodilation, intravascular fluid loss, and possible myocardial depression. If multiple organ systems were involved, reviewers selected the organ failure that predominantly led to cardiorespiratory arrest.