Mesenteric artery response to head-up tilt-induced central hypovolaemia and hypotension
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Mesenteric artery response to head-up tilt-induced central hypovolaemia and hypotension. / Perko, M J; Madsen, P; Perko, Grazyna; Schroeder, T V; Secher, N H.
I: Clinical physiology (Oxford, England), Bind 17, Nr. 5, 01.09.1997, s. 487-496.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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T1 - Mesenteric artery response to head-up tilt-induced central hypovolaemia and hypotension
AU - Perko, M J
AU - Madsen, P
AU - Perko, Grazyna
AU - Schroeder, T V
AU - Secher, N H
PY - 1997/9/1
Y1 - 1997/9/1
N2 - Superior mesenteric artery (SMA) blood flow and impedance were evaluated by duplex ultrasound during head-up tilt (HUT)-induced central hypovolaemia and hypotension in eight healthy volunteers. HUT induced a reduction in cardiac stroke volume from 88.8 +/- 6.3 to 64.7 +/- 6.3 ml (mean +/- SEM; P <0.01) and an increase in thoracic electric impedance from 38.6 +/- 2.1 to 42.6 +/- 2.1 omega (P <0.01) reflecting a reduced central blood volume. Maintained tilt provoked a 30% reduction in mean arterial pressure (from 87.1 +/- 3.3 to 63.4 +/- 3.6 mmHg: P <0.01) and the appearance of presyncopal symptoms. During both the normotensive and the hypotensive phase of HUT, the SMA diameter (5.7 +/- 0.03 mm) and blood flow (514 +/- 75 ml min-1) did not change significantly, although the end-diastolic velocity increased from 9.7 +/- 4.8 to 39.7 +/- 4.0 cm s-1 (P <0.01). The increase in diastolic velocity, despite a maintained or reduced arterial pressure, supports a reduction in the SMA impedance as it was reproduced during a meal test when a moderate reduction in mean arterial pressure (87 +/- 4 to 80 +/- 4 mm Hg; P = 0.04) was accompanied by a ninefold increase in the end-diastolic velocity (P <0.01). The results indicate a reduction in the mesenteric vascular impedance to the extent that superior mesenteric artery blood flow is maintained during HUT-induced central hypovolaemia and hypotension.
AB - Superior mesenteric artery (SMA) blood flow and impedance were evaluated by duplex ultrasound during head-up tilt (HUT)-induced central hypovolaemia and hypotension in eight healthy volunteers. HUT induced a reduction in cardiac stroke volume from 88.8 +/- 6.3 to 64.7 +/- 6.3 ml (mean +/- SEM; P <0.01) and an increase in thoracic electric impedance from 38.6 +/- 2.1 to 42.6 +/- 2.1 omega (P <0.01) reflecting a reduced central blood volume. Maintained tilt provoked a 30% reduction in mean arterial pressure (from 87.1 +/- 3.3 to 63.4 +/- 3.6 mmHg: P <0.01) and the appearance of presyncopal symptoms. During both the normotensive and the hypotensive phase of HUT, the SMA diameter (5.7 +/- 0.03 mm) and blood flow (514 +/- 75 ml min-1) did not change significantly, although the end-diastolic velocity increased from 9.7 +/- 4.8 to 39.7 +/- 4.0 cm s-1 (P <0.01). The increase in diastolic velocity, despite a maintained or reduced arterial pressure, supports a reduction in the SMA impedance as it was reproduced during a meal test when a moderate reduction in mean arterial pressure (87 +/- 4 to 80 +/- 4 mm Hg; P = 0.04) was accompanied by a ninefold increase in the end-diastolic velocity (P <0.01). The results indicate a reduction in the mesenteric vascular impedance to the extent that superior mesenteric artery blood flow is maintained during HUT-induced central hypovolaemia and hypotension.
M3 - Journal article
VL - 17
SP - 487
EP - 496
JO - Clinical Physiology
JF - Clinical Physiology
SN - 0144-5979
IS - 5
ER -
ID: 216763