title: 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.
authors.affiliation: School of Nursing and Rehabilitation Sciences at Odawara, International University of Health and Welfare, Odawara, Kanagawa 250-8588, Japan. Electronic address: satoshi@iuhw.ac.jp.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kubota
authors.affiliation: School of Nursing and Rehabilitation Sciences at Odawara, International University of Health and Welfare, Odawara, Kanagawa 250-8588, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Endo
authors.affiliation: School of Nursing and Rehabilitation Sciences at Odawara, International University of Health and Welfare, Odawara, Kanagawa 250-8588, Japan.
authors.forename: Mitsue
authors.initials: M
authors.lastname: Kubota
authors.affiliation: New Life Yugawara, Yugawara, Kanagawa, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ishizuka
authors.affiliation: Social Welfare Corporation Keiroen, Ueda, Nagano, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Furudate
mesh_terms: D002302:Cardiac Output / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*; D055815:Young Adult
keywords: Cardiovascular regulation; Impedance cardiography; Systolic time intervals