Al-Sufayan F, Bamehrez M, Kwiatkowski K, Alvaro R E
Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada.
Pediatr Pulmonol. 2009 Mar;44(3):253-9. doi: 10.1002/ppul.20989.
Airway closure during central apnea could allow for better gas exchange. However, the return of inspiratory efforts against a closed airway may cause greater desaturation and prolongation of apnea.
To investigate the effect of patency of the airway and obstructed respiratory efforts on the length of apneas and the degree and slope of O(2) desaturation and bradycardia.
All mixed apneas observed in 15 preterms were matched 1:2 with the longest central apneas in each infant. Central apneas were further classified using the amplified cardiac airflow oscillation in those with airway open and in those with airway closed.
No differences were found in the length of apnea, slope of O(2) desaturation, delay between the onset of apnea and onset of desaturation, lowest post-apneic SpO(2), and time of recovery of SpO(2) between central apneas with and without airway closure. Although mixed apneas were significantly longer than central apneas, their initial central component was significantly shorter than the length of central apneas. In mixed apneas, the onset of O(2) desaturation occurred faster, SpO(2) decreased lower, and recovered slower compared with central apneas. The slope of O(2) desaturation after the obstructed respiratory efforts was significantly greater than before the obstructed respiratory efforts.
In preterm infants: (1) airway closure during central apneas does not limit oxygen desaturation; (2) respiratory efforts against a closed airway prolong apnea and worsen the degree of desaturation and bradycardia. Although respiratory efforts are not necessary to induce airway closure, inspiratory efforts against a closed airway could trigger inhibitory cardio-respiratory responses causing significant desaturation, bradycardia, and prolongation of apnea.
中枢性呼吸暂停期间气道关闭可能有利于更好的气体交换。然而，针对关闭气道的吸气努力恢复可能会导致更严重的氧饱和度下降和呼吸暂停延长。
研究气道通畅情况和受阻呼吸努力对呼吸暂停时长、氧饱和度下降程度及斜率以及心动过缓的影响。
对15名早产儿观察到的所有混合性呼吸暂停与每个婴儿最长的中枢性呼吸暂停按1:2进行匹配。利用气道开放和气道关闭时的心脏气流振荡放大情况对中枢性呼吸暂停进行进一步分类。
在有气道关闭和无气道关闭的中枢性呼吸暂停之间，呼吸暂停时长、氧饱和度下降斜率、呼吸暂停开始至氧饱和度下降开始的延迟、呼吸暂停后最低SpO₂以及SpO₂恢复时间均未发现差异。尽管混合性呼吸暂停明显长于中枢性呼吸暂停，但其初始中枢部分明显短于中枢性呼吸暂停的时长。在混合性呼吸暂停中，与中枢性呼吸暂停相比，氧饱和度下降开始得更快，SpO₂下降得更低，恢复得更慢。受阻呼吸努力后的氧饱和度下降斜率明显大于受阻呼吸努力前。
在早产儿中：(1)中枢性呼吸暂停期间气道关闭并不限制氧饱和度下降；(2)针对关闭气道的呼吸努力会延长呼吸暂停，并使氧饱和度下降程度和心动过缓恶化。尽管诱导气道关闭并不一定需要呼吸努力，但针对关闭气道的吸气努力可能会触发抑制性心肺反应，导致明显的氧饱和度下降、心动过缓和呼吸暂停延长。
