Allyn J W, Teplick R, Steinberg J B, Munfakh N A, Geffin G A, Titus J, Daggett W M
Department of Anesthesia, Massachusetts General Hospital, Boston 02114.
Am J Physiol. 1992 Sep;263(3 Pt 2):H715-21. doi: 10.1152/ajpheart.1992.263.3.H715.
To test for oxygen wasting by norepinephrine (NE) without relying on normalization by measures of performance such as the pressure-volume area, myocardial oxygen consumption (MVO2) was determined for isovolumic beats at five different left ventricular (LV) end-diastolic volumes (EDV) in nine isolated cross-perfused canine hearts in each of three states: a basal anesthetic state (B); after depression with halothane (H); and after adding NE to increase contractility back to the B state (H+NE). The end-diastolic and peak systolic pressure-volume lines were identical for B and H+NE. The R2 for a linear regression of MVO2 per beat for B vs. H+NE for beats originating at the same EDV and developing similar (within 10%) peak isovolumic pressures for all hearts was 0.85. The slope and intercept were 0.83 and 0.01, which are significantly less than one (P less than 0.001) and greater than zero (P less than 0.001), respectively. These data suggest that NE increases both the economy of pressure development as well as activation energy of an isovolumically contracting LV.
为了在不依赖诸如压力 - 容积面积等性能指标进行标准化的情况下，测试去甲肾上腺素（NE）导致的氧耗，在三种状态下，对九个离体交叉灌注犬心脏中五个不同的左心室（LV）舒张末期容积（EDV）时的等容搏动测定心肌耗氧量（MVO2）：基础麻醉状态（B）；氟烷抑制后（H）；以及添加NE使收缩力恢复到B状态后（H + NE）。B状态和H + NE状态下的舒张末期和收缩期峰值压力 - 容积线相同。对于所有心脏中源自相同EDV且产生相似（在10%以内）等容峰值压力的搏动，B状态与H + NE状态下每搏MVO2的线性回归R2为0.85。斜率和截距分别为0.83和0.01，分别显著小于1（P < 0.001）且大于0（P < 0.001）。这些数据表明，NE既增加了压力产生的经济性，也增加了等容收缩左心室的活化能。
