Toubas P L, Hof R P, Heymann M A, Rudolph A M
Arch Fr Pediatr. 1978 Dec;35(10 Suppl):84-92.
Thirteen unanesthetized lambs, aged 1-3 days, were cooled from 40 degrees to 30 degrees C and then rewarmed. During cooling, heart rate dropped from 196 +/- 47 to 140 +/- 42 beats per minute, a 29% change; cardiac output, femoral arterial and pulse pressures did not change significantly; but inferior vena cava pressure (IVC) increased from 5 to 9 mm of mercury, and left ventricular end diastolic pressure (LVEDP) increased from 8 to 25 mm/Hg. Mean pulmonary arterial pressure increased from 29 to 40 mm/Hg. Metabolic acidosis and hypoxia developed during the cooling. There were marked changes in the distribution of cardiac output; the proportion of cardiac output increased by 450% to brown fat, 66% to the skeletal muscles, and 30% to the right ventricular myocardium and atria. No significant change in the distribution to the left ventricule and septum was observed. Distribution to the other organs decreased markedly. After rewarming, all the previous parameters returned to normal except CVP and LVEDP, which remained elevated.
13只1至3日龄未麻醉的羔羊被从40摄氏度冷却至30摄氏度，然后再复温。冷却过程中，心率从每分钟196±47次降至140±42次，变化了29%；心输出量、股动脉压和脉压无显著变化；但下腔静脉压（IVC）从5毫米汞柱升至9毫米汞柱，左心室舒张末期压（LVEDP）从8毫米汞柱升至25毫米汞柱。平均肺动脉压从29毫米汞柱升至40毫米汞柱。冷却过程中出现代谢性酸中毒和低氧血症。心输出量分布有显著变化；心输出量分配到棕色脂肪的比例增加了450%，分配到骨骼肌的比例增加了66%，分配到右心室心肌和心房的比例增加了30%。观察到分配到左心室和室间隔的比例无显著变化。分配到其他器官的比例显著下降。复温后，除中心静脉压（CVP）和左心室舒张末期压（LVEDP）仍升高外，所有先前参数均恢复正常。
