Cerebrovascular and cardiovascular responses to the Valsalva manoeuvre during hyperthermia

IF 1.3 4区医学 Q4 PHYSIOLOGY

Clinical Physiology and Functional Imaging Pub Date : 2023-06-18 DOI:10.1111/cpf.12843

Blake G. Perry, Stephanie Korad, Toby Mündel

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Abstract

Background

During hyperthermia, the perturbations in mean arterial blood pressure (MAP) produced by the Valsalva manoeuvre (VM) are more severe. However, whether these more severe VM-induced changes in MAP are translated to the cerebral circulation during hyperthermia is unclear.

Methods

Healthy participants (n = 12, 1 female, mean ± SD: age 24 ± 3 years) completed a 30 mmHg (mouth pressure) VM for 15 s whilst supine during normothermia and mild hyperthermia. Hyperthermia was induced passively using a liquid conditioning garment with core temperature measured via ingested temperature sensor. Middle cerebral artery blood velocity (MCAv) and MAP were recorded continuously during and post-VM. Tieck's autoregulatory index was calculated from the VM responses, with pulsatility index, an index of pulse velocity (pulse time) and mean MCAv (MCAv_mean) also calculated.

Results

Passive heating significantly raised core temperature from baseline (37.9 ± 0.2 vs. 37.1 ± 0.1°C at rest, p < 0.01). MAP during phases I through III of the VM was lower during hyperthermia (interaction effect p < 0.01). Although an interaction effect was observed for MCAv_mean (p = 0.02), post-hoc differences indicated only phase IIa was lower during hyperthermia (55 ± 12 vs. 49.3 ± 8 cm s⁻¹ for normothermia and hyperthermia, respectively, p = 0.03). Pulsatility index was increased 1-min post-VM in both conditions (0.71 ± 0.11 vs. 0.76 ± 0.11 for pre- and post-VM during normothermia, respectively, p = 0.02, and 0.86 ± 0.11 vs. 0.99 ± 0.09 for hyperthermia p < 0.01), although for pulse time only main effects of time (p < 0.01), and condition (p < 0.01) were apparent.

Conclusion

These data indicate that the cerebrovascular response to the VM is largely unchanged by mild hyperthermia.

Abstract Image

查看原文本刊更多论文

热疗过程中对Valsalva操作的脑血管和心血管反应。

背景：在热疗过程中，瓦尔萨尔瓦手法（VM）产生的平均动脉血压（MAP）扰动更为严重。然而，这些更严重的VM诱导的MAP变化是否在热疗过程中转化为脑循环尚不清楚。方法：健康参与者（n = 12，1名女性，平均 ± SD：24岁 ± 3年）完成了30 mmHg（口腔压力）VM持续15 在常温和轻度热疗期间仰卧。使用液体调理服被动诱导热疗，通过摄入的温度传感器测量核心温度。在VM期间和之后连续记录大脑中动脉血流速度（MCAv）和MAP。根据VM反应计算Tieck的自动调节指数，并计算脉动指数、脉搏速度（脉搏时间）指数和平均MCAv（MCAvmean）。结果：被动加热显著提高了核心温度（37.9 ± 0.2对37.1 ± 静止时0.1°C，p 平均值（p = 0.02），事后差异表明只有IIa期在热疗过程中较低（55 ± 12对49.3 ± 8. 厘米 s-1分别用于常温和高温，p = 0.03）。在两种情况下，VM后1分钟脉动指数均增加（0.71 ± 0.11对0.76 ± 常温期间VM前和VM后分别为0.11，p = 0.02和0.86 ± 0.11对0.99 ± 0.09用于热疗p 结论：这些数据表明，轻度高温对VM的脑血管反应基本上没有变化。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Clinical Physiology and Functional Imaging 医学-生理学

CiteScore

3.40

自引率

5.60%

发文量

审稿时长

6-12 weeks

期刊介绍： Clinical Physiology and Functional Imaging publishes reports on clinical and experimental research pertinent to human physiology in health and disease. The scope of the Journal is very broad, covering all aspects of the regulatory system in the cardiovascular, renal and pulmonary systems with special emphasis on methodological aspects. The focus for the journal is, however, work that has potential clinical relevance. The Journal also features review articles on recent front-line research within these fields of interest. Covered by the major abstracting services including Current Contents and Science Citation Index, Clinical Physiology and Functional Imaging plays an important role in providing effective and productive communication among clinical physiologists world-wide.