Lewis K W, Bosque E M
Department of Pediatrics, California Pacific Medical Center, San Francisco 94118, USA.
J Pediatr. 1995 Nov;127(5):691-9. doi: 10.1016/s0022-3476(95)70155-9.
To determine whether fetal exposure to cigarette smoke impairs postnatal chemoreceptor control of ventilation and hypercapnic and hypoxic awakening responses.
Smoking (n = 13) and nonsmoking (n = 34) women were recruited during pregnancy. Serum cotinine levels were measured to assess level of nicotine exposure. The infants were studied at 2 to 3 months of age for ventilatory and awakening responses to hypoxia (17%, 15% and 13% inspired O2) and hypercapnia 4%, 6%, and 8% inspired CO2). Continuous measures were analyzed with unpaired t tests and analysis of variance for repeated measures. Proportions of awakening and periodic breathing were analyzed by means of a comparison of proportions.
The infants of smokers had lower birth weights (3022 +/- 566 vs 3518 +/- 491 gm; p < or = 0.005) and were older at the time of study (10.4 +/- 2.8 vs 8.7 +/- 1.3 weeks; p < 0.01) than the control infants. Maternal cotinine levels were higher in smokers (97.8 +/- 107 ng/ml vs no cotinine; p < 0.0001). More infants of smokers failed to awaken with hypoxia than did control infants (54% vs 15%; p = 0.006). The ventilatory responses to hypoxia and hypercapnia were similar in the two groups. All infants awakened with hypercapnia, and there was no difference in the awakening threshold for carbon dioxide (50.3 +/- 4.5 vs 48.3 +/- 5.4 mm Hg; p = 0.28).
Infants of mothers who smoked during pregnancy have deficient hypoxic awakening responses, which may contribute to the increased risk of sudden infant death syndrome in infants of smoking mothers.
确定胎儿暴露于香烟烟雾是否会损害出生后化学感受器对通气的控制以及高碳酸血症和低氧唤醒反应。
在孕期招募吸烟（n = 13）和不吸烟（n = 34）的女性。测量血清可替宁水平以评估尼古丁暴露程度。在婴儿2至3个月大时研究其对低氧（吸入氧浓度为17%、15%和13%）和高碳酸血症（吸入二氧化碳浓度为4%、6%和8%）的通气及唤醒反应。连续测量结果用非配对t检验和重复测量方差分析进行分析。唤醒和周期性呼吸的比例通过比例比较进行分析。
吸烟者的婴儿出生体重较低（3022±566 vs 3518±491克；p≤0.005），且在研究时年龄较大（10.4±2.8 vs 8.7±1.3周；p<0.01），高于对照组婴儿。吸烟者的母体可替宁水平更高（97.8±107 ng/ml vs 无可替宁；p<0.0001）。与对照组婴儿相比，更多吸烟者的婴儿在低氧时未能唤醒（54% vs 15%；p = 0.006）。两组对低氧和高碳酸血症的通气反应相似。所有婴儿在高碳酸血症时均会唤醒，二氧化碳唤醒阈值无差异（50.3±4.5 vs 48.3±5.4 mmHg；p = 0.28）。
孕期吸烟母亲的婴儿低氧唤醒反应不足，这可能导致吸烟母亲的婴儿发生婴儿猝死综合征的风险增加。
