TY - JOUR

T1 - Cardiovascular and neuroendocrine responses to left lateral position in non-obese young males

AU - Schou, M

AU - Pump, B

AU - Gabrielsen, A

AU - Thomsen, C

AU - Christensen, N J

AU - Warberg, J

AU - Norsk, P

PY - 2001/12/1

Y1 - 2001/12/1

N2 - Previous results from our laboratory indicate that the heart is distended by the left lateral position (LAT) compared to horizontal supine (SUP). We therefore tested the hypothesis that cardiac output is increased by LAT and that mean arterial pressure is maintained unchanged or even decreased through peripheral vasodilatation induced by cardiopulmonary low-pressure receptor stimulation. Twelve non-obese young males were investigated. The location of the mid-aorta between the aortic valves was used as the hydrostatic reference point for the arterial pressure measurements. It was determined by magnetic resonance (n=6) to be 7.0 +/- 0.2 cm below the sternum in SUP (1/3 of anteroposterior chest diameter below the sternum) and 2.5 +/- 0.2 cm below the midsternal level in LAT. Brachial mean (auscultation) and finger mean arterial pressures (infrared photoplethysmography), cardiac output (foreign gas rebreathing), heart rate, and plasma concentrations (n=6) of vasoactive hormones were unchanged by LAT. In conclusion, cardiac output, mean arterial pressures, and vasoactive hormone releases were unaffected by 30 min of LAT. Furthermore, the hydrostatic reference points for arterial pressure measurements is located one third of the antero-posterior chest diameter below the sternum in SUP and 2.5 cm below the midsternal level in LAT in non-obese young males.

AB - Previous results from our laboratory indicate that the heart is distended by the left lateral position (LAT) compared to horizontal supine (SUP). We therefore tested the hypothesis that cardiac output is increased by LAT and that mean arterial pressure is maintained unchanged or even decreased through peripheral vasodilatation induced by cardiopulmonary low-pressure receptor stimulation. Twelve non-obese young males were investigated. The location of the mid-aorta between the aortic valves was used as the hydrostatic reference point for the arterial pressure measurements. It was determined by magnetic resonance (n=6) to be 7.0 +/- 0.2 cm below the sternum in SUP (1/3 of anteroposterior chest diameter below the sternum) and 2.5 +/- 0.2 cm below the midsternal level in LAT. Brachial mean (auscultation) and finger mean arterial pressures (infrared photoplethysmography), cardiac output (foreign gas rebreathing), heart rate, and plasma concentrations (n=6) of vasoactive hormones were unchanged by LAT. In conclusion, cardiac output, mean arterial pressures, and vasoactive hormone releases were unaffected by 30 min of LAT. Furthermore, the hydrostatic reference points for arterial pressure measurements is located one third of the antero-posterior chest diameter below the sternum in SUP and 2.5 cm below the midsternal level in LAT in non-obese young males.

KW - Adult

KW - Arginine Vasopressin

KW - Atrial Natriuretic Factor

KW - Blood Pressure

KW - Cardiac Output

KW - Heart Rate

KW - Hemodynamics

KW - Hormones

KW - Humans

KW - Male

KW - Norepinephrine

KW - Posture

KW - Renin

KW - Vasodilation

M3 - Journal article

C2 - 12365446

VL - 8

SP - 15

EP - 19

JO - Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology

JF - Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology

SN - 1077-9248

IS - 2

ER -