Miller M J, Martin R J, Carlo W A, Fouke J M, Strohl K P, Fanaroff A A
J Pediatr. 1985 Sep;107(3):465-9. doi: 10.1016/s0022-3476(85)80535-7.
Newborn infants are considered obligate nasal breathers, hence dependent on a patent nasal airway for ventilation. The conditions under which oral breathing could occur and the contribution of oral ventilation to total ventilation were studied in 30 healthy term infants (aged 1 to 3 days). Nasal and oral airflow were measured using two resistance-matched pneumotachometers, and heart rate, tcPO2, etCO2, and sleep state were continuously recorded. In three of 10 infants studied in undisturbed sleep, spontaneous oronasal breathing was noted during both active and quiet sleep (mean duration 19 +/- 25 minutes), the distribution of tidal volume being 70% +/- 12% nasal and 30% +/- 12% oral. Episodes of oronasal breathing were also observed after crying in six infants (mean duration 21 +/- 19 seconds). In an additional 20 infants, multiple 15-second end-expiratory nasal occlusions were performed; eight (40%) of these infants initiated and sustained oral breathing in response to nasal occlusion. Respiratory rate, tidal volume, heart rate, and tcPO2 did not change when oral breathing occurred in response to nasal occlusion, although minute ventilation decreased from 265 to 199 ml/min/kg (P less than 0.05). These results demonstrate that newborn infants may use the oral airway for ventilation, both spontaneously and in response to complete nasal occlusion.
新生儿被认为是必须经鼻呼吸的，因此依赖通畅的鼻气道进行通气。我们对30名足月健康婴儿（年龄1至3天）进行了研究，观察他们在何种情况下会出现经口呼吸以及经口通气对总通气量的贡献。使用两个阻力匹配的呼吸流速计测量鼻气流和口气流，并持续记录心率、经皮血氧分压（tcPO2）、呼气末二氧化碳分压（etCO2）和睡眠状态。在10名处于安静睡眠状态的婴儿中，有3名在主动睡眠和安静睡眠期间均出现了自发的口鼻呼吸（平均持续时间19±25分钟），潮气量分布为70%±12%经鼻和30%±12%经口。6名婴儿在哭闹后也观察到了口鼻呼吸发作（平均持续时间21±19秒）。在另外20名婴儿中，进行了多次15秒的呼气末鼻阻塞；其中8名（40%）婴儿在鼻阻塞时开始并维持经口呼吸。当因鼻阻塞而出现经口呼吸时，呼吸频率、潮气量、心率和tcPO2均未改变，尽管分钟通气量从265降至199毫升/分钟/千克（P<0.05）。这些结果表明，新生儿在自发情况下以及对完全鼻阻塞做出反应时，可能会使用口腔气道进行通气。
