Effects of trunk posture in Fowler's position on hemodynamics

Abstract

We speculated that stroke volume would be higher and heart rate would be lower when the head and upper trunk were mainly upright in the Fowler's position. We therefore analyzed the effects of three trunk postures in Fowler's position on heart rate, blood pressure and circulatory volume. Heart rate (HR), blood pressure (BP), stroke volume (SV), cardiac output (Q), systemic vascular resistance (SVR), ejection time (ET) and pre-ejection period (PEP) were measured in 10 healthy male volunteers (mean age ± SEM, 20.7 ± 0.5 y; range, 19-23 y) while in three trunk postures in Fowler's position. Stroke volume and Q were measured using impedance cardiography. The three trunk postures were 30° of lower and upper trunk inclination (WT30°), 30° and 60° of lower and upper trunk inclination (UT 60°), respectively and 60° of upper and lower trunk inclination (WT60°). Both SV and ET were significantly higher and HR and PEP were lower at UT60° than at WT60° (p < 0.01) whereas these values did not significantly differ between WT30° and UT60° (p > 0.05). None of Q, SVR and BP significantly differed among the three conditions (p > 0.05). These findings suggested that SV and preload are higher when the upper trunk is upright (UT60°) than when the entire trunk is upright (WT60°) while in Fowler's position. In addition, Q might be maintained without increasing HR through vagal withdrawal when only the upper trunk is upright in healthy young males in Fowler's position.

Assessment of effects of differences in trunk posture during Fowler&rsquo;s position on hemodynamics and cardiovascular regulation in older and younger subjects

“…How posture can prevent the hypovolemia and hypotension caused by orthostatic stress during Fowler’s position is important and should be addressed. Our previous study indicated that Fowler’s position with an upright upper trunk is effective for maintaining circulatory volume with lower tachycardia via vagal withdrawal compared with having the whole trunk upright in younger subjects 25. However, whether an upright upper trunk in Fowler’s position allows easy maintenance of circulatory volume in cases with autonomic hypofunction associated with aging remains unclear.…”

Effect of Carbohydrate-Enriched Drink Compared to Fasting on Hemodynamics in Healthy Volunteers. A Randomized Trial

“…Liu et al used the ICG device during cardiopulmonary exercise testing and six-minute walk test to improve peak oxygen uptake assessment in healthy volunteers [27]. ICG proved useful in assessing the impact of postural changes on haemodynamic parameters in healthy adults [28], infants [29][30][31], and surgery patients [32].…”

Abstracts of the 2016 Student Paramedics Australasia Conference

“…A position used instead of supine to assist with breathing, monitoring haemodynamics and minimising risk of aspiration in vomiting. It has been suggested that an inclination of 30°of the lower trunk and 60°of upper trunk to be the most effective positioning compared to a whole upright trunk-results in lower heart rate, greater stroke volume and preload (p<0.01) (Kubota, Endo, Kubota, Ishizuka & Furudate, 2015). (Kubota, Endo, Kubota, Ishizuka & Furudate, 2015) Aspirin:…”