Passive leg raising is widely used to treat hypotension associated with hypovolemia. Presumably gravity causes a central translocation of leg venous blood and an increase in filling pressure, cardiac output, and arterial pressure. Ten healthy volunteers, 25 to 35 years old, had measurements of heart rate, blood pressure, and cardiac output in the supine position after 20 sec and 7 min of 60 degrees passive leg elevation. The protocol was performed 3 and 45 min after the subjects changed from an ambulatory upright to a supine position. Stroke volume and cardiac output increased transiently (8-10%) when the legs were raised after 3 min rest in the supine position. By 7 min of leg elevation, these beneficial effects disappeared. After 45 min supine, leg raising had no effect on stroke volume or cardiac output but increased blood pressure (4 mm Hg) by increasing peripheral resistance (15%). Thus, leg raising, like application of the MAST trousers, fails to produce any sustained increase in cardiac output or stroke volume. Small venous leg volumes and time-dependent changes in the distribution of venous volume and compliance may explain the absence of any sustained 'autotransfusion' effect.
[Show abstract][Hide abstract] ABSTRACT: Straight raising of the legs in the supine position or Trendelenburg positioning has been used to treat hypotension or shock, but the advantages of these positions are not clear and under debate. We performed a crossover study to evaluate the circulatory effect of full flexion of the hips and knees in the supine position (exaggerated lithotomy), and compare it with straight leg raising.
This study was a prospective randomized crossover study from the tertiary care unit at our university hospital. Twenty-two patients scheduled for off-pump coronary artery bypass surgery were enrolled. Induction and maintenance of anesthesia were standardized. Exaggerated lithotomy position or straight leg raising were randomly selected in the supine position. Hemodynamic variables were measured in the following sequence: 10 min after induction, 1, 5, and 10 min following the designated position, and 1 and 5 min after returning to the supine position. Ten min later, the other position was applied to measure the same hemodynamic variables.
During the exaggerated lithotomy position, cerebral and coronary perfusion pressure increased significantly (P < 0.01) without a change in cardiac output. During straight leg raising, cardiac output increased at 5 min (P < 0.05) and cerebral and coronary perfusion pressures did not increase except for cerebral perfusion pressure at 1 min. However, the difference between the two groups at each time point in terms of cerebral perfusion pressure was clinically insignificant.
Full flexion of the hips and knees in the supine position did not increase cardiac output but may be more beneficial than straight leg raising in terms of coronary perfusion pressure.
Korean journal of anesthesiology 04/2012; 62(4):317-21. DOI:10.4097/kjae.2012.62.4.317
"Many experimental and clinical studies have shown, however, that PLE has no or little haemodynamic benefit in normovolaemic patients with a stable cardiocirculatory status [2,8,9,10,11]. Studying the haemodynamic effects of the manoeuvre in anaesthetized coronary patients with a rapid-response thermistor pulmonary artery catheter , Reich et al. concluded that PLE results in minor haemodynamic improvement, in right ventricular dilatation and in right ventricular ejection fraction (RVEF) decrease . "
[Show abstract][Hide abstract] ABSTRACT: The aim of the present study was to evaluate the haemodynamic effects of passive leg elevation on the right ventricular function in two groups of patients, one with a normal right ventricular ejection fraction (RVEF) and one with a reduced RVEF.
Twenty coronary patients undergoing elective coronary artery bypass grafting surgery were studied by a RVEF pulmonary artery catheter. The haemodynamic data reported were collected before the induction of anaesthesia (time point 1), just before (time point 2) and 1 min (time point 3) after the legs were simultaneously raised at 60 degrees, and 1 min after the legs were lowered (time point 4). The patients were divided into two groups: group A, with preinduction RVEF > 45%; and group B, with preinduction RVEF < 40%.
In group A (n = 10), at time point 3 compared with time point 2, the heart rate significantly decreased (from 75 +/- 10 to 66 +/- 7 beats/min). The right ventricular end diastolic volume index (from 105 +/- 17 to 133 +/- 29 ml/m2), the right ventricular end systolic volume index (from 61 +/- 13 to 77 +/- 24 ml/m2), the systolic systemic arterial/right ventricular pressure gradient (from 93 +/- 24 to 113 +/- 22 mmHg) and the diastolic systemic arterial/right ventricular pressure gradient (from 58 +/- 11 to 66 +/- 12 mmHg) significantly increased. Also in group A, the cardiac index did not significantly increase (from 3.28 +/- 0.6 to 3.62 +/- 0.6 l/min/m2), the RVEF was unchanged, and the right ventricular end diastolic volume/pressure ratio (RVED V/P) did not significantly decrease (from 48 +/- 26 to 37 +/- 13 ml/mmHg). In group B (n = 6) at the same time, the heart rate (from 72 +/- 15 to 66 +/- 12 beats/min), the right ventricular end diastolic volume index (from 171 +/- 50 to 142 +/- 32 ml/m2) and the RVED V/P (from 71 +/- 24 to 39 +/- 7 ml/mmHg) significantly decreased. The cardiac index and the diastolic systemic arterial/right ventricular pressure gradient were unchanged in group B, while the RVEF and the systolic systemic arterial/right ventricular pressure gradient did not significantly increase, and the right ventricular end-systolic volume index did not significantly decrease. All results are expressed as mean +/- standard deviation.
We conclude that passive leg elevation caused a worse condition in the right ventricle of group B because, with stable values of cardiac index, of systolic systemic arterial/right ventricular pressure gradient and of diastolic systemic arterial/right ventricular pressure gradient (which supply oxygen), the RVED V/P (to which oxygen consumption is inversely related) markedly decreased. This is as opposed to group A, where the cardiac index, the systolic systemic arterial/right ventricular pressure gradient and the diastolic systemic arterial/right ventricular pressure gradient increased, and the RVED V/P slightly decreased. Passive leg elevation must therefore be performed cautiously in coronary patients with a reduced RVEF.
Critical Care 05/2003; 7(2):164-70. DOI:10.1186/cc1882 · 4.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Pendant de nombreuses années, la gestion du remplissage vasculaire en réanimation a reposé essentiellement sur le concept
de fluid challenge (1). Il s’agit d’une évaluation a posteriori de la réponse au remplissage, basée sur un monitorage invasif du débit cardiaque et des pressions intracardiaques (1). Une
expansion volémique est jugée efficace lorsqu’elle entraîne une augmentation significative du débit cardiaque associée à une
faible augmentation des pressions de remplissage, le coeur fonctionnant alors sur la portion raide de la courbe de Starling
(2); elle est jugée inefficace lorsqu’elle n’entraîne qu’une augmentation modeste voire nulle du débit cardiaque mais importante
des pressions de remplissage, le coeur fonctionnant alors sur la portion plate de la courbe de Starling (2). Cette attitude
a été rendue nécessaire par l’absence de paramètres hémodynamiques permettant de prédire fidèlement l’efficacité du remplissage.
Historiquement, les paramètres évaluant la précharge cardiaque (droite ou gauche) avaient été préconisés pour guider le remplissage
vasculaire. La pression veineuse centrale (PVC), comme la pression artérielle pulmonaire d’occlusion, ont été montrées insuffisamment
fiables pour prédire le bénéfice hémodynamique du remplissage vasculaire (3, 4). Les dimensions ventriculaires ne le sont
pas davantage (5, 6). Si l’efficacité de l’expansion volémique reste vraisemblable pour les valeurs très basses de précharge
parfois rencontrées chez les patients non encore réanimés (7), l’attitude basée sur l’analyse des marqueurs statiques de précharge
cardiaque est peu recommandable, une fois passées les toutes premières heures de la réanimation hémodynamique.
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