TY - JOUR

T1 - The decrease of cardiac chamber volumes and output during positive-pressure ventilation.

AU - Kristensen, Kasper Kyhl

AU - Ahtarovski, Kiril Aleksov

AU - Iversen, Kasper

AU - Thomsen, Carsten

AU - Vejlstrup, Niels Grove

AU - Engstrøm, Thomas

AU - Lav Madsen, Per

PY - 2013/10/1

Y1 - 2013/10/1

N2 - Positive-pressure ventilation (PPV) is widely used for treatment of acute cardiorespiratory failure, occasionally at the expense of compromised cardiac function and arterial blood pressure. The explanation why has largely rested on interpretation of intracardiac pressure changes. We evaluated the effect of PPV on the central circulation by studying cardiac chamber volumes with cardiac magnetic resonance imaging (CMR). We hypothesized that PPV lowers cardiac output (CO) mainly via the Frank-Starling relationship. In 18 healthy volunteers, cardiac chamber volumes and flow in aorta and the pulmonary artery were measured by CMR during PPV levels of 0, 10, and 20 cmH2O applied via a respirator and a face mask. All cardiac chamber volumes decreased in proportion to the level of PPV. Following 20-cmH2O PPV, the total diastolic and systolic cardiac volumes (±SE) decreased from 605 (±29) ml to 446 (±29) ml (P < 0.001) and from 265 (±17) ml to 212 (±16) ml (P < 0.001). Left ventricular stroke volume decreased by 27 (±4) ml/beat; heart rate increased by 7 (±2) beats/min; and CO decreased by 1.0 (±0.4) l/min (P < 0.001). From 0 to 20 cmH2O, right and left ventricular peak filling rates decreased by −146 (±32) and −187 (±64) ml/s (P < 0.05) but maximal emptying rates were unchanged. Cardiac filling and output decrease with increasing PPV in healthy volunteers. The decrease is seen even at low levels of PPV and should be taken into account when submitting patients to mechanical ventilation with positive pressures. The decrease in CO is fully explained by the Frank-Starling mechanism.

AB - Positive-pressure ventilation (PPV) is widely used for treatment of acute cardiorespiratory failure, occasionally at the expense of compromised cardiac function and arterial blood pressure. The explanation why has largely rested on interpretation of intracardiac pressure changes. We evaluated the effect of PPV on the central circulation by studying cardiac chamber volumes with cardiac magnetic resonance imaging (CMR). We hypothesized that PPV lowers cardiac output (CO) mainly via the Frank-Starling relationship. In 18 healthy volunteers, cardiac chamber volumes and flow in aorta and the pulmonary artery were measured by CMR during PPV levels of 0, 10, and 20 cmH2O applied via a respirator and a face mask. All cardiac chamber volumes decreased in proportion to the level of PPV. Following 20-cmH2O PPV, the total diastolic and systolic cardiac volumes (±SE) decreased from 605 (±29) ml to 446 (±29) ml (P < 0.001) and from 265 (±17) ml to 212 (±16) ml (P < 0.001). Left ventricular stroke volume decreased by 27 (±4) ml/beat; heart rate increased by 7 (±2) beats/min; and CO decreased by 1.0 (±0.4) l/min (P < 0.001). From 0 to 20 cmH2O, right and left ventricular peak filling rates decreased by −146 (±32) and −187 (±64) ml/s (P < 0.05) but maximal emptying rates were unchanged. Cardiac filling and output decrease with increasing PPV in healthy volunteers. The decrease is seen even at low levels of PPV and should be taken into account when submitting patients to mechanical ventilation with positive pressures. The decrease in CO is fully explained by the Frank-Starling mechanism.

KW - Faculty of Health and Medical Sciences

KW - cardiac physiology

KW - positive-pressure ventilation

KW - cardiovascular mag- netic resonance

KW - central hemodynamic

KW - mechanical ventilation

KW - Frank- Starling relationship

U2 - 10.1152/ajpheart.00309.2013

DO - 10.1152/ajpheart.00309.2013

M3 - Journal article

C2 - 23893161

VL - 305

SP - H1004-9

JO - American Journal of Physiology: Heart and Circulatory Physiology

JF - American Journal of Physiology: Heart and Circulatory Physiology

SN - 0363-6135

IS - 7

ER -