cause of accidental death in toddlers A history of abrupt onset of choking or gagging is suggestive Drooling, dysphagia, and stridor suggest an upper airway foreign body, whereas unilateral wheeze, particularly first-time wheeze with acute onset, suggests lower airway position Presentation, particularly with lower airway foreign body, may be delayed by days to weeks from time of aspiration TABLE 71.1 Criteria for Respiratory Failure a Clinical Laboratory Tachypnea, bradypnea, PaO2 30 Paco2 >60 mm Hg and rising mm Hg Decreased or absent pH