Torres Luciana N, Torres Filho Ivo P, Barbee R Wayne, Tiba M Hakam, Ward Kevin R, Pittman Roland N
Department of Physiology, Virginia Commonwealth University Reanimation Engineering Shock Center, Virginia Commonwealth University Health System, Richmond, Virginia 23298-0695, USA.
Am J Physiol Heart Circ Physiol. 2004 May;286(5):H1811-20. doi: 10.1152/ajpheart.00837.2003. Epub 2004 Jan 15.
Studies are needed to provide a rigorous examination of the relevance of monitored variables during prolonged hemorrhagic hypotension (HH). This study was designed to investigate the parameters that describe biochemical and O2 transport patterns in animals subjected to HH. Systemic parameters that could differentiate survivors from nonsurvivors were identified. An aortic flow probe was implanted in rats (n = 21) for continuous measurement of cardiac output. Experiments were performed 6-9 days after surgery. Rats were bled to a mean arterial pressure of 40 mmHg and kept at that level using Ringer-lactate solution. Arterial and venous blood pressures, gases, acid-base status, glucose, lactate, electrolytes, hemoglobin, O2 saturation, heart and respiratory rates, total peripheral resistance, and O2 delivery and consumption were measured before hemorrhage, soon after 40 mmHg was reached, and 0.5, 1, 2, 3, and 4 h later. Fifty-three percent of rats survived > or =3 h (survivors); others were considered nonsurvivors. Nonsurvivors showed a significantly greater degree of metabolic acidosis than survivors. Arterial PO2, respiratory rate, O2 saturation, O2 content, glucose, and pH were significantly higher in survivors. The rate of Ringer-lactate infusion, arterial K+, and PCO2 were lower in survivors. Arterial K+ and respiratory rate were the only parameters significantly different between survivors and nonsurvivors at all time points during HH. Arterial levels of K+ showed the clearest distinction between survivors and nonsurvivors and may explain the sudden death experienced by animals during HH. The data suggest that early respiratory and metabolic compensations are essential for survival of prolonged HH.
需要开展研究，以严格检验长时间失血性低血压（HH）期间监测变量的相关性。本研究旨在调查描述HH动物生化和氧气运输模式的参数。确定能够区分存活者与非存活者的全身参数。在大鼠（n = 21）体内植入主动脉流量探头，用于连续测量心输出量。实验在手术后6 - 9天进行。将大鼠放血至平均动脉压40 mmHg，并使用乳酸林格液维持该水平。在出血前、达到40 mmHg后不久以及之后0.5、1、2、3和4小时测量动脉和静脉血压、气体、酸碱状态、葡萄糖、乳酸、电解质、血红蛋白、血氧饱和度、心率和呼吸频率、总外周阻力以及氧气输送和消耗。53%的大鼠存活≥3小时（存活者）；其他大鼠被视为非存活者。非存活者的代谢性酸中毒程度明显高于存活者。存活者的动脉血氧分压、呼吸频率、血氧饱和度、氧含量、葡萄糖和pH值显著更高。存活者的乳酸林格液输注速率、动脉血钾和二氧化碳分压较低。在HH期间的所有时间点，动脉血钾和呼吸频率是存活者与非存活者之间唯一显著不同的参数。动脉血钾水平在存活者和非存活者之间显示出最明显的差异，可能解释了动物在HH期间突然死亡的原因。数据表明，早期呼吸和代谢补偿对于长时间HH的存活至关重要。
