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AnswerThe tube would become mechanical deadspace. We are always rebreathing some exhaled C02 because of our physiological dead space (ie trachea, upper airway). The longer the tube the more C02 is inhaled. If the child were to constantly breath through the tube without interruption it would take a great deal of time to build PaC02 to any kind of dangerous level. Even if high C02 levels were to build, the initial mental effects would cause the child to give up on the tube and easily ventilate himself back to normal levels (highly unlikely). The tube also adds a small increase in airway resistance which is not likey of any concern. The reality is most children don't have the attention span and determination to breath through a gift wrap tube constantly for that long. Important thing here is to watch your child for any abnormal symptoms as usuall and if the tube is making you that worried offer an alternative game.Cheers! how does smoking.exercising,anxiety,drygs,environmantal factors,attitude and weight affect your breathing?