简介:每天暴露于轻度间歇性缺氧(MIH)后,缺氧期间和之后的静息分钟通气和通气可能会增强。相比之下,每天暴露于MIH后,静息收缩压(SBP)降低。然而,目前尚不清楚每日暴露后静息收缩压是否降低,在急性暴露于MIH期间和之后,SBP反应降低。方法:患有阻塞性睡眠呼吸暂停(OSA)和高血压(n=10)的参与者每天暴露于12次2分钟的MIH(氧饱和度-87%)发作15天。对照组(n=6)暴露于假手术方案,在此期间压缩空气(即,FIO2=0.21)代替MIH。结果:从最初的第一次到最后一次低氧发作,低氧通气反应(HVR)和低氧收缩压反应(HSBP)增加(HVR:0.08±0.02vs.0.13±0.02L/min/mmHg,p=0.03;HSBP:0.13±0.04vs.0.37±0.06mmHg/mmHg,p<0.001)和最终(HVR:0.10±0.01vs.0.15±0.03L/min/mmHg,p=0.03;HSBP:0.16±0.03vs.0.41±0.34mmHg/mmHg,p<0.001)天。天之间的增加幅度没有差异(p≥0.83)。暴露于MIH后,与初始基线相比,分钟通气量和SBP升高(MV:16.70±1.10vs.14.20±0.28L/min,p=0.01;SBP:167.26±4.43vs.151.13±4.56mmHg,p<0.001)和最终(MV:17.90±1.25vs.15.40±0.77L/min,p=0.01;SBP:156.24±3.42vs.137.18±4.17mmHg,p<0.001)天。两天的增加幅度相似(MV:3.68±1.69vs.3.22±1.27L/min,SBP:14.83±2.64vs.14.28±1.66mmHg,p≥0.414)。尽管有这些相似之处,与初始日相比,MIH方案中基线和其他时间点的血压在最后一天降低(p≤0.005).结论:急性MIH期间和之后的通气和血压反应在暴露的第一天和最后一天相似。或者,血压被下调,而通风在所有时间点都相似(即,基线,在MIH期间和之后)每天暴露于MIH后。
Introduction: Resting minute ventilation and ventilation during and following hypoxia may be enhanced following daily exposure to mild intermittent hypoxia (MIH). In contrast, resting systolic blood pressure (SBP) is reduced following daily exposure to MIH. However, it is presently unknown if the reduction in resting SBP following daily exposure, is coupled with reduced SBP responses during and after acute exposure to MIH. Methods: Participants with obstructive sleep apnea (OSA) and hypertension (n = 10) were exposed to twelve 2-min bouts of MIH (oxygen saturation-87%)/day for 15 days. A control group (n = 6) was exposed to a sham protocol during which compressed air (i.e., FIO2 = 0.21) was inspired in place of MIH. Results: The hypoxic ventilatory response (HVR) and hypoxic systolic blood pressure response (HSBP) increased from the first to the last hypoxic episode on the initial (HVR: 0.08 ± 0.02 vs. 0.13 ± 0.02 L/min/mmHg, p = 0.03; HSBP: 0.13 ± 0.04 vs. 0.37 ± 0.06 mmHg/mmHg, p < 0.001) and final (HVR: 0.10 ± 0.01 vs. 0.15 ± 0.03 L/min/mmHg, p = 0.03; HSBP: 0.16 ± 0.03 vs. 0.41 ± 0.34 mmHg/mmHg, p < 0.001) day. The magnitude of the increase was not different between days (p ≥ 0.83). Following exposure to MIH, minute ventilation and SBP was elevated compared to baseline on the initial (MV: 16.70 ± 1.10 vs. 14.20 ± 0.28 L/min, p = 0.01; SBP: 167.26 ± 4.43 vs. 151.13 ± 4.56 mmHg, p < 0.001) and final (MV: 17.90 ± 1.25 vs. 15.40 ± 0.77 L/min, p = 0.01; SBP: 156.24 ± 3.42 vs. 137.18 ± 4.17 mmHg, p < 0.001) day. The magnitude of the increases was similar on both days (MV: 3.68 ± 1.69 vs. 3.22 ± 1.27 L/min, SBP: 14.83 ± 2.64 vs. 14.28 ± 1.66 mmHg, p ≥ 0.414). Despite these similarities, blood pressure at baseline and at other time points during the MIH protocol was reduced on the final compared to the initial day (p ≤ 0.005). Conclusion: The ventilatory and blood pressure responses during and following acute MIH were similar on the initial and final day of exposure. Alternatively, blood pressure was down regulated, while ventilation was similar at all time points (i.e., baseline, during and following MIH) after daily exposure to MIH.