Effect of upper torso inclination in Fowler’s position on autonomic cardiovascular regulation

Endo

et al. 2015

Autonomic Neuroscience

Self Cite

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.

Section: Hemodynamicssupporting

confidence: 92%

Effects of trunk posture in Fowler's position on hemodynamics

Endo

et al. 2015

Autonomic Neuroscience

Self Cite

IEEE J. Biomed. Health Inform.

“…During spontaneous breathing test, the patients had an upper torso inclination of 35º -40º. Results published by Kubota et al suggested that slight flexion of the upper torso in Fowler's position activates respiratory function and increases the contribution of vagal nerve activity to the cardiovascular system [41]. This could explain the low variability of sympathetic weight factors of baroreflex control (A s).…”

Section: Discussionmentioning

confidence: 99%

Modeling of Heart Rate Variability and Respiratory Muscle Activity in Organophosphate Poisoned Patients

Salazar

Mañanas

Daza

2019

We propose an extended model of cardiovascular regulation to assess heart rate variability in patients poisoned with organophosphate during their treatment with mechanical ventilation. The model was modified to fit a population of twentyone (21) patients poisoned with organophosphorus compounds and undergoing mechanical ventilation. The extended model incorporated the respiratory muscle activity measured by surface electromyography for quantifying the vagal-sympathetic engagement during spontaneous breathing test. The order and structure of the parasympathetic and the sympathetic transfer function with respect to the original model were modified to a second-order system. In this extended model, the parameters related to the vagal-sympathetic response (corner frequency and constant gain) were correlated with respiratory muscle activity. When the diaphragm's contractions were stronger, the sympathetic corner frequency increased while the parasympathetic corner frequency and gain decreased. Thus the proposed model could be useful to improve the ventilatory support and pharmacological treatment for patients poisoned with organophosphorus compounds considering the vagalsympathetic response inferred from the respiratory muscle activity.

“…We operationally defined total lying time as the period within 24 hours each day spent in horizontal or near-horizontal position (e.g., Fowler position 24 ) , semi-Fowler position 25 ) , not involving high-Fowler position 26 ) ) in spite of the presence or absence of sleeping, napping, receiving massage, watching television, listening to radio, and so on, regardless of purpose or location. Firstly, participants were asked to recall retrospectively the average time per day they spent horizontally lying in the previous week in increments of 30 minutes as follows: “How many hours per day did you typically spend lying with or without doing something like sleeping, napping, receiving massage, watching television, listening to radio, or other on a usual day, regardless of purpose or place in the previous week?” The question to measure total lying time is referred to in previous studies as the single question to measure total sitting time 15 ) and the definition of sedentary behavior 2 , 27 ) .…”

Section: Participants and Methodsmentioning

confidence: 99%

Single question about total lying time for assessing physical inactivity in community-dwelling older adults: a study of reliability and discriminant validity from sleeping time

Kaneya

Hashidate

2020

J Phys Ther Sci

[Purpose] To investigate reliability and discriminant validity of a single question about total lying time for assessing physical inactivity in community-dwelling older people. [Participants and Methods] The participants were 54 healthy older individuals (mean age, 72.5 years), who were asked to recall retrospectively their mean total lying and sleep times per day in the previous week (7 days). The total lying and sleep times per day in the forthcoming week (7 days) were also investigated prospectively after confirming the mean total lying and sleep times per day in the previous week, and their mean values per day were calculated. [Results] Intraclass reliability of total lying and sleep times per day in the forthcoming week were acceptable [ICC (1, 1) for total lying time=0.835, ICC (1, 1) for sleep time=0.707]. No significant difference in average total lying time between the previous (8.4 ± 2.0 hours/day) and forthcoming (8.7 ± 1.7 hours/day) weeks was seen. In the forthcoming week, average total lying time was significantly higher than average sleep time (7.1 ± 1.3 hours/day). There was low significant correlation between total lying time and sleep time. [Conclusion] Total lying time can be measured with acceptable reliability and discriminant validity, and is a different outcome than sleep time in community-dwelling older adults.