Zhou X S, Shahabuddin S, Zahn B R, Babcock M A, Badr M S
John D. Dingell Veterans Affairs Medical Center, and Division of Pulmonary and Critical Care Medicine, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
J Appl Physiol (1985). 2000 Jul;89(1):192-9. doi: 10.1152/jappl.2000.89.1.192.
We hypothesized that a decreased susceptibility to the development of hypocapnic central apnea during non-rapid eye movement (NREM) sleep in women compared with men could be an explanation for the gender difference in the sleep apnea/hypopnea syndrome. We studied eight men (age 25-35 yr) and eight women in the midluteal phase of the menstrual cycle (age 21-43 yr); we repeated studies in six women during the midfollicular phase. Hypocapnia was induced via nasal mechanical ventilation for 3 min, with respiratory frequency matched to eupneic frequency. Tidal volume (VT) was increased between 110 and 200% of eupneic control. Cessation of mechanical ventilation resulted in hypocapnic central apnea or hypopnea, depending on the magnitude of hypocapnia. Nadir minute ventilation in the recovery period was plotted against the change in end-tidal PCO(2) (PET(CO(2))) per trial; minute ventilation was given a value of 0 during central apnea. The apneic threshold was defined as the x-intercept of the linear regression line. In women, induction of a central apnea required an increase in VT to 155 +/- 29% (mean +/- SD) and a reduction of PET(CO(2)) by -4.72 +/- 0.57 Torr. In men, induction of a central apnea required an increase in VT to 142 +/- 13% and a reduction of PET(CO(2)) by -3.54 +/- 0.31 Torr (P = 0.002). There was no difference in the apneic threshold between the follicular and the luteal phase in women. Premenopausal women are less susceptible to hypocapnic disfacilitation during NREM sleep than men. This effect was not explained by progesterone. Preservation of ventilatory motor output during hypocapnia may explain the gender difference in sleep apnea.
我们推测，与男性相比，女性在非快速眼动（NREM）睡眠期间发生低碳酸血症性中枢性呼吸暂停的易感性降低，可能是睡眠呼吸暂停/低通气综合征性别差异的一个解释。我们研究了8名男性（年龄25 - 35岁）和处于月经周期黄体中期的8名女性（年龄21 - 43岁）；在卵泡中期对6名女性重复进行了研究。通过鼻机械通气诱导低碳酸血症3分钟，呼吸频率与平静呼吸频率匹配。潮气量（VT）增加至平静呼吸对照的110%至200%。根据低碳酸血症的程度，停止机械通气会导致低碳酸血症性中枢性呼吸暂停或呼吸浅慢。将恢复期的最低分钟通气量与每次试验的呼气末二氧化碳分压（PET(CO₂)）变化作图；在中枢性呼吸暂停期间分钟通气量取值为0。呼吸暂停阈值定义为线性回归线的x轴截距。在女性中，诱导中枢性呼吸暂停需要将VT增加至155±29%（平均值±标准差），PET(CO₂)降低-4.72±0.57 Torr。在男性中，诱导中枢性呼吸暂停需要将VT增加至142±13%，PET(CO₂)降低-3.54±0.31 Torr（P = 0.002）。女性卵泡期和黄体期的呼吸暂停阈值没有差异。绝经前女性在NREM睡眠期间比男性更不易受低碳酸血症性呼吸抑制的影响。这种效应无法用孕酮来解释。低碳酸血症期间通气运动输出的保留可能解释了睡眠呼吸暂停的性别差异。
