Seifert John, McNair Megan, Declercq Patricia, St Cyr John
Department of Health and Human Development, Montana State University, Box 173360, 103 Romney Gym, Bozeman, MT 59717, USA.
Ther Adv Cardiovasc Dis. 2013 Jun;7(3):123-9. doi: 10.1177/1753944713481512. Epub 2013 May 1.
Exposure to cold has been shown to cause cardiovascular stress and increased morbidity and mortality. Inhalation of cold, dry air can increase blood pressure and induce myocardial ischemia, particularly in people with preexisting hypertensive cardiovascular disease. Face masks that can warm and humidify inhaled cold air may reduce these cold air pressor effects.
We compared blood pressure measurements using a heat and moisture exchange mask (HME), a placebo mask (PL), and no mask (NM) in 53 patients with hypertension exposed to a cold chamber environment at -5°C for 1 h. Blood pressure and heart rate were recorded at baseline, and at 15 min intervals from 0 to 60 min of chamber exposure. All patients were taking antihypertensive medications with drug and dosage determined by their own physicians. Data were analyzed by a one-way analysis of variance test with repeated measures, and significant interactions were analyzed by Fisher's least significant differences tests. A post hoc subgroup analysis for the effect of age was performed using Wilcoxon matched-pair rank tests.
Wearing the HME resulted in significantly lower systolic and mean arterial blood pressures than the PL and NM conditions. Diastolic blood pressures were significantly lower for the HME than the NM, but not the PL condition.
Subgroup analyses suggested that the effect of the HME in mitigating systolic blood pressure increase from inhalation of cold air was significantly greater for patients aged 60 years or over than for those under 60 years.
已有研究表明，暴露于寒冷环境会导致心血管应激反应，并增加发病率和死亡率。吸入寒冷、干燥的空气会使血压升高并诱发心肌缺血，尤其是在患有高血压性心血管疾病的人群中。能够对吸入的冷空气进行加热和加湿的面罩可能会减轻这些冷空气升压效应。
我们比较了53例高血压患者在-5°C的冷室环境中暴露1小时时，使用热湿交换面罩（HME）、安慰剂面罩（PL）和不使用面罩（NM）时的血压测量结果。在基线时以及在冷室暴露0至60分钟期间每隔15分钟记录一次血压和心率。所有患者均在服用降压药物，药物及剂量由其各自的医生确定。数据采用重复测量的单因素方差分析进行分析，显著的交互作用采用Fisher最小显著差异检验进行分析。使用Wilcoxon配对秩和检验对年龄的影响进行事后亚组分析。
与使用PL和NM的情况相比，佩戴HME导致收缩压和平均动脉压显著降低。HME组的舒张压显著低于NM组，但与PL组无显著差异。
亚组分析表明，对于60岁及以上的患者，HME减轻吸入冷空气导致的收缩压升高的效果明显优于60岁以下的患者。
