Mennitto Serena, Harrison Johanna, Ritz Thomas, Robillard Pierre, France Christopher R, Ditto Blaine
McGill University, Montreal, Quebec, Canada.
Southern Methodist University, Dallas, Texas.
Transfusion. 2019 Feb;59(2):566-573. doi: 10.1111/trf.15046. Epub 2018 Nov 29.
Whether produced by breathing too fast or too deeply, hyperventilation is common in stressful situations and may contribute to blood donation-related vasovagal symptoms. The effects of some previously tested interventions for vasovagal symptoms, for example, applied tension (AT), may be related to reduction of hyperventilation. More targeted breathing techniques might be useful.
This was a randomized controlled trial comparing the effects of AT, a slow, shallow "anti-hyperventilation" breathing technique previously tested in phobic individuals (respiration control [RESP]), the combination of AT and RESP, and no intervention on blood donors participating in university clinics. A total of 547 eligible donors were assigned randomly to one of these four groups. Observational, self-report, and physiologic measures (primarily via respiratory capnometry) were obtained.
Although both RESP and AT had some positive impact on blood donation outcome, the effects of RESP were more numerous, albeit limited primarily to donors who had less general fear of medical procedures. For example, lower-fear donors assigned to practice RESP had significantly lower Blood Donation Reaction Inventory scores and were significantly less likely to require treatment for symptoms than no-treatment individuals. In general, RESP led to a significant decrease in respiration rate, though it did not influence end-tidal CO , a more precise measure of hyperventilation.
While the mechanisms remain somewhat unclear and the interventions did not benefit more fearful, higher-risk donors, respiration control is a promising additional approach to reducing vasovagal symptoms.
无论是呼吸过快还是过深所导致的过度换气，在压力情境中都很常见，并且可能会引发与献血相关的血管迷走神经症状。一些先前测试过的针对血管迷走神经症状的干预措施，例如应用紧张法（AT），其效果可能与减少过度换气有关。更具针对性的呼吸技巧可能会有所帮助。
这是一项随机对照试验，比较了AT、一种先前在恐惧症患者中测试过的缓慢、浅呼吸的“抗过度换气”呼吸技巧（呼吸控制[RESP]）、AT与RESP的组合，以及对参与大学诊所献血者不进行干预的效果。共有547名符合条件的献血者被随机分配到这四组中的一组。获取了观察性、自我报告和生理测量数据（主要通过呼吸二氧化碳测定法）。
尽管RESP和AT对献血结果都有一些积极影响，但RESP的效果更多，尽管主要限于对医疗程序总体恐惧较小的献血者。例如，被分配练习RESP的低恐惧献血者的献血反应量表得分显著更低，并且与未接受治疗的个体相比，出现症状需要治疗的可能性显著更小。总体而言，RESP导致呼吸频率显著降低，尽管它并未影响呼气末二氧化碳水平，而呼气末二氧化碳水平是衡量过度换气的更精确指标。
虽然机制仍有些不清楚，且这些干预措施对更恐惧、风险更高的献血者没有益处，但呼吸控制是减少血管迷走神经症状的一种有前景的额外方法。
