Gilgoff I S, Peng R C, Keens T G
University of Southern California Medical School, Rancho Los Amigos Medical Center, Downey 90242.
Chest. 1992 Jun;101(6):1500-6. doi: 10.1378/chest.101.6.1500.
Uncuffed tracheostomy tubes are used for long-term mechanical ventilation in children. However, upper airway mechanics differ between sleep and wakefulness; this may affect air leak around tracheostomies. We studied 19 children with high cervical spinal cord injury on portable positive pressure ventilators, age range birth to 19 years. Ventilator settings were adjusted while awake to achieve PaCO2 less than 45 mm Hg and PO2 greater than 90 mm Hg. Clinically several children with uncuffed tracheostomies became unstable at night with seizures and sleep disruption. Nine of 11 children on volume controlled systems were found to be inadequately ventilated during sleep. Substitution with a cuffed tracheostomy allowed adequate ventilation both awake and asleep, suggesting that inadequate ventilation during sleep was due to an uncompensated leak around the uncuffed tracheostomy. To avoid cuffed tracheostomies, eight children received pressure controlled ventilation. Gas exchange was adequate throughout the day and night. We conclude that children receiving volume controlled mechanical ventilation via uncuffed tracheostomy tubes can exhibit hypoventilation due to uncompensated air leak. Pressure controlled ventilation improves adequacy of gas exchange during sleep and wakefulness.
无套囊气管造口管用于儿童的长期机械通气。然而，睡眠和清醒状态下上呼吸道力学有所不同；这可能会影响气管造口周围的漏气情况。我们研究了19名使用便携式正压通气机的高位颈脊髓损伤儿童，年龄范围从出生到19岁。在清醒状态下调整通气机设置，以使动脉血二氧化碳分压（PaCO2）低于45毫米汞柱，动脉血氧分压（PO2）高于90毫米汞柱。临床上，几名使用无套囊气管造口管的儿童在夜间出现癫痫发作和睡眠中断，变得不稳定。在容量控制通气系统的11名儿童中，有9名在睡眠期间通气不足。更换为有套囊气管造口管后，清醒和睡眠时通气均充足，这表明睡眠期间通气不足是由于无套囊气管造口周围未得到补偿的漏气所致。为避免使用有套囊气管造口管，8名儿童接受了压力控制通气。昼夜气体交换均充足。我们得出结论，通过无套囊气管造口管接受容量控制机械通气的儿童可能会因未得到补偿的漏气而出现通气不足。压力控制通气可改善睡眠和清醒期间气体交换的充足性。
