Young Tim M, Mathias Christopher J
Neurovascular Medicine Unit, Imperial College London at St. Mary's Hospital, London W2 1NY, UK.
Auton Neurosci. 2004 Jun 30;113(1-2):79-81. doi: 10.1016/j.autneu.2004.05.006.
The oral ingestion of water increases seated blood pressure in chronic autonomic failure although the mechanisms of this effect remain unclear. Recent studies in normal subjects suggest that oropharyngeal stimulation during swallowing may be of greater importance in causing a rise in blood pressure (BP) than the gastric effects of water. We therefore assessed the haemodynamic effects of water instilled directly into the stomach via a gastrostomy tube in pure autonomic failure (PAF).
The subject had longstanding (>20 years) PAF. A gastrostomy tube had been previously placed because of dysphagia. Distilled water (480 ml) was instilled in the seated position with BP and heart rate (HR) measured over the following 40 min while the subject remained seated. Systolic and diastolic BP (SBP and DBP) and heart rate (HR) were recorded intermittently every 3 min with a Dinamap automated syphgmomanometer and continuously using a Portapres device. Subsequent model flow analysis of the Portapres data provided beat-to-beat estimates of cardiac output, stroke volume, and total peripheral resistance (TPR). Subjective orthostatic symptoms were recorded before and after water.
Seated SBP and DBP increased after water instillation with increases first noted between 5 and 8 min after the water had been instilled. The BP remained elevated until 35 min post water increase over baseline being +36.5 mm Hg SBP and +24.3 mm Hg DBP. HR, cardiac output, and stroke volume remained unchanged during the study. Total peripheral resistance (TPR) increased post water. These results are similar to those reported in a recent study involving oral ingestion of 480 ml of water in PAF subjects.
Instilling water directly into the stomach in a patient with PAF resulted in similar haemodynamic responses to those seen when water is taken orally. Thus, oropharyngeal factors and swallowing do not appear to be essential in the generation of the water pressor effect in autonomic failure.
尽管慢性自主神经功能衰竭患者口服水后坐位血压升高的机制尚不清楚，但近期对正常受试者的研究表明，吞咽过程中的口咽刺激可能比水对胃的影响在导致血压升高方面更为重要。因此，我们评估了通过胃造瘘管直接向胃内注入水对纯自主神经功能衰竭（PAF）患者的血流动力学影响。
该受试者患有长期（>20年）PAF。因吞咽困难先前已置入胃造瘘管。在受试者坐位时注入蒸馏水（480 ml），并在随后40分钟内测量血压和心率（HR），期间受试者保持坐位。使用Dinamap自动血压计每3分钟间歇记录收缩压和舒张压（SBP和DBP）以及心率（HR），并使用Portapres设备持续记录。随后对Portapres数据进行模型血流分析，以逐搏估计心输出量、每搏量和总外周阻力（TPR）。记录注水前后的主观直立症状。
注水后坐位SBP和DBP升高，在注水后5至8分钟之间首次出现升高。血压持续升高直至注水后35分钟，较基线升高SBP 36.5 mmHg和DBP 24.3 mmHg。在研究期间，HR、心输出量和每搏量保持不变。注水后总外周阻力（TPR）增加。这些结果与最近一项涉及PAF受试者口服480 ml水的研究报告结果相似。
对PAF患者直接向胃内注入水产生的血流动力学反应与口服水时相似。因此，口咽因素和吞咽似乎并非自主神经功能衰竭时水升压效应产生的必要条件。
Zotero 插件