Poets C F, Stebbens V A, Samuels M P, Southall D P
Department of Paediatric Pulmonology, Medical School, Hannover, Germany.
Pediatr Res. 1993 Aug;34(2):144-7. doi: 10.1203/00006450-199308000-00007.
The pathogenesis of bradycardias in preterm infants is poorly understood. Because their pathogenesis may involve both apnea and hypoxemia, we set out to analyze the proportion of bradycardias that were associated with an apneic pause and/or a fall in arterial oxygen saturation (SaO2), and the temporal sequence of the three phenomena, in overnight tape recordings of SaO2 (Nellcor N100 in beat-to-beat mode), breathing movements, nasal airflow, and ECG in 80 preterm infants at the time of discharge from hospital. A bradycardia was defined as a fall in heart rate of > or = 33% from baseline for > or = 4 s, an apneic pause as a cessation of breathing movements and/or airflow for > or = 4 s, and a desaturation as a fall in SaO2 to < or = 80%. A total of 193 bradycardias were found in 46 (58%) of the recordings (median, three per recording; range 1-18). There was a close relationship between bradycardias, apneic pauses, and desaturations: 83% of bradycardias were associated with apneic pauses and 86% with desaturations. Where all three phenomena occurred in combination, the time from the onset of apnea to the onset of the fall in SaO2 was shorter (median interval, 0.8 s; range -4.9-+ 11.5 s) than that from the onset of apnea to the onset of bradycardia (median, 4.8 s; range -4.0-+ 14.0 s). Hence, most bradycardias (86%) commenced after the onset of the fall in SaO2. We conclude that bradycardia, apnea, and hypoxemia are closely linked phenomena in preterm infants.
早产儿心动过缓的发病机制尚不清楚。由于其发病机制可能涉及呼吸暂停和低氧血症，我们着手分析在80例早产儿出院时进行的夜间脉搏血氧饱和度（Nellcor N100，逐搏模式）、呼吸运动、鼻气流和心电图记录中，与呼吸暂停和/或动脉血氧饱和度（SaO2）下降相关的心动过缓比例，以及这三种现象的时间顺序。心动过缓定义为心率较基线下降≥33%且持续≥4秒，呼吸暂停定义为呼吸运动和/或气流停止≥4秒，血氧饱和度下降定义为SaO2降至≤80%。在46份（58%）记录中总共发现193次心动过缓（中位数为每份记录3次；范围为1 - 18次）。心动过缓、呼吸暂停和血氧饱和度下降之间存在密切关系：83%的心动过缓与呼吸暂停相关，86%与血氧饱和度下降相关。当这三种现象同时出现时，从呼吸暂停开始到SaO2下降开始的时间（中位数间隔为0.8秒；范围为 - 4.9 - + 11.5秒）比从呼吸暂停开始到心动过缓开始的时间（中位数为4.8秒；范围为 - 4.0 - + 14.0秒）短。因此，大多数心动过缓（86%）在SaO2下降开始后出现。我们得出结论，心动过缓、呼吸暂停和低氧血症在早产儿中是密切相关的现象。
