Breathing Research and Therapeutics Center and Department of Physical Therapy, University of Florida, Gainesville, Florida, USA.
McKnight Brain Institute, University of Florida, Gainesville, Florida, USA.
J Neurotrauma. 2024 Sep;41(17-18):2114-2124. doi: 10.1089/neu.2023.0353. Epub 2024 Apr 18.
Brief exposure to repeated episodes of low inspired oxygen, or acute intermittent hypoxia (AIH), is a promising therapeutic modality to improve motor function after chronic, incomplete spinal cord injury (SCI). Although therapeutic AIH is under extensive investigation in persons with SCI, limited data are available concerning cardiorespiratory responses during and after AIH exposure despite implications for AIH safety and tolerability. Thus, we recorded immediate (during treatment) and enduring (up to 30 min post-treatment) cardiorespiratory responses to AIH in 19 participants with chronic SCI (>1 year post-injury; injury levels C1 to T6; American Spinal Injury Association Impairment Scale A to D; mean age = 33.8 ± 14.1 years; 18 males). Participants completed a single AIH (15, 60-sec episodes, inspired O ≈ 10%; 90-sec intervals breathing room air) and Sham (inspired O ≈ 21%) treatment, in random order. During hypoxic episodes: (1) arterial oxyhemoglobin saturation decreased to 82.1 ± 2.9% ( < 0.001); (2) minute ventilation increased 3.83 ± 2.29 L/min ( = 0.008); and (3) heart rate increased 4.77 ± 6.82 bpm ( = 0.010). Considerable variability in cardiorespiratory responses was found among subjects; some individuals exhibited large hypoxic ventilatory responses (≥0.20 L/min/%, = 11), whereas others responded minimally (<0.20 L/min/%, = 8). Apneas occurred frequently during AIH and/or Sham protocols in multiple participants. All participants completed AIH treatment without difficulty. No significant changes in ventilation, heart rate, or arterial blood pressure were found 30 min post-AIH > 0.05). In conclusion, therapeutic AIH is well tolerated, elicits variable chemoreflex activation, and does not cause persistent changes in cardiorespiratory control/function 30 min post-treatment in persons with chronic SCI.
短暂暴露于重复的低氧吸入或急性间歇性低氧（AIH）是一种有前途的治疗方法，可以改善慢性不完全性脊髓损伤（SCI）后的运动功能。尽管在 SCI 患者中广泛研究了治疗性 AIH，但有关 AIH 暴露期间和之后的心肺反应的数据有限，尽管这对 AIH 的安全性和耐受性有影响。因此，我们记录了 19 名慢性 SCI 患者（损伤后> 1 年；损伤水平 C1 至 T6；美国脊髓损伤协会损伤量表 A 至 D；平均年龄= 33.8 ± 14.1 岁；18 名男性）在 AIH 暴露时的即时（治疗期间）和持久（治疗后 30 分钟）心肺反应。参与者完成了单次 AIH（15 次，60 秒的缺氧期，吸入 O ≈ 10%；90 秒的空气呼吸间隔期）和假处理（吸入 O ≈ 21%），随机进行。在缺氧期：（1）动脉血氧饱和度下降至 82.1 ± 2.9%（ < 0.001）；（2）分钟通气量增加 3.83 ± 2.29 L/min（ = 0.008）；（3）心率增加 4.77 ± 6.82 bpm（ = 0.010）。在受试者之间发现心肺反应存在相当大的可变性；一些人表现出较大的缺氧通气反应（≥0.20 L/min/%， = 11），而其他人则反应较小（<0.20 L/min/%， = 8）。在多个参与者中，AIH 和/或 Sham 方案中经常发生呼吸暂停。所有参与者都顺利完成了 AIH 治疗。AIH 后 30 分钟，通气、心率或动脉血压均无显著变化 > 0.05）。总之，治疗性 AIH 耐受性良好，引起了不同的化学感受器激活，并且在慢性 SCI 患者中不会导致治疗后 30 分钟心肺控制/功能的持续变化。
