Nozaki Junpei, Kitahata Hiroshi, Tanaka Katsuya, Kawahito Shinji, Oshita Shuzo
Department of Anesthesiology, Tokushima University School of Medicine, Tokushima, Japan.
Anesth Analg. 2002 May;94(5):1120-6, table of contents. doi: 10.1097/00000539-200205000-00011.
Acute normovolemic hemodilution (ANH) increases cardiac output because of a reduction in blood viscosity and enhancement of left ventricular (LV) contractility. The status of LV function, especially LV diastolic function during ANH, remains controversial. We therefore examined LV systolic and diastolic function during ANH. Sixteen dogs were anesthetized with isoflurane in the absence (Group 1) and presence (Group 2) of beta-adrenergic blockade (propranolol 1 mg/kg). LV contractility was quantified by the slope (M(w)) of the stroke work and end-diastolic volume relation. Diastolic function was evaluated with the time constant of LV relaxation (T), chamber stiffness constant (K(c)), peak LV diastolic filling rate during early filling (peak E) and atrial contraction (peak A), and ratio of peak E to peak A (E/A). Normovolemic exchange of blood (50 mL/kg) for 6% hydroxyethyl starch (ANH50) significantly increased M(w) in Group 1 but not in Group 2. In both groups, ANH50 significantly decreased T. ANH50 significantly increased peak E in both groups and peak A in Group 1, and it did not change the E/A ratio or K(c) in either group. ANH causes positive inotropic effects and enhances diastolic function without beta-blockade. Even after beta-adrenergic blockade, ANH improves diastolic function through the reduction of LV ejection impedance.
Acute normovolemic hemodilution enhances LV (left ventricular) diastolic function by alterations in the LV loading condition produced by hemodilution, which mainly contributes to a compensatory increase in cardiac output.
急性等容血液稀释（ANH）可因血液粘度降低和左心室（LV）收缩力增强而增加心输出量。ANH期间LV功能的状态，尤其是LV舒张功能，仍存在争议。因此，我们研究了ANH期间LV的收缩和舒张功能。16只犬在无β-肾上腺素能阻滞剂（第1组）和有β-肾上腺素能阻滞剂（第2组，普萘洛尔1mg/kg）的情况下用异氟烷麻醉。通过每搏功与舒张末期容积关系的斜率（M(w)）来量化LV收缩力。用LV松弛时间常数（T）、心室僵硬度常数（K(c)）、早期充盈期间LV舒张期最大充盈率（E峰）和心房收缩（A峰）以及E峰与A峰之比（E/A）来评估舒张功能。用6%羟乙基淀粉进行等容血液交换（50mL/kg）（ANH50）使第1组的M(w)显著增加，但第2组未增加。在两组中，ANH50均显著降低T。ANH50使两组的E峰均显著增加，使第1组的A峰显著增加，且两组的E/A比值或K(c)均未改变。ANH在无β-阻滞剂的情况下产生正性肌力作用并增强舒张功能。即使在β-肾上腺素能阻滞剂作用后，ANH仍可通过降低LV射血阻抗来改善舒张功能。
急性等容血液稀释通过血液稀释引起的LV负荷条件改变来增强LV（左心室）舒张功能，这主要有助于心输出量的代偿性增加。
