Bergø G W, Risberg J, Tyssebotn I
Department of Physiology, University of Bergen, Norway.
Undersea Biomed Res. 1988 Nov;15(6):457-70.
The distribution of cardiac output (CO) was studied in conscious rats during hyperbaric oxygen (HBO) exposure to 5 bar for 60 min. Heart rate (HR) and arterial blood pressure (ABP) were continuously recorded. Organ blood flow and CO were measured during control, after 5 and 60 min HBO by the microsphere method. Arterial acid-base balance was measured both during control and HBO. During HBO the animals remained calm and seemed unstressed with no sign of convulsions. The arterial pH remained at control level, whereas PCO2 and HCO3 fell (P less than 0.05). The systolic ABP increased gradually during HBO, while the mean ABP was unchanged. HR started to fall at 1 bar O2 (P less than 0.05), fell markedly during compression (P less than 0.02), and remained below control level during the HBO. After atropine was given, HR increased to predive control in all animals. CO fell by 25% due to increased total peripheral vascular resistance of 27%. Blood flow to most organs fell correspondingly to CO, indicating an equally distributed vasoconstriction. Unchanged blood flow was found in the kidneys, the adrenals, and the liver. Blood flow to the right and left heart ventricles fell significantly more than the average reduction of CO. Calculation of a pump work index of the heart by the product of systolic ABP and HR showed unchanged performance, while the blood flow to the left ventricle fell by 50%, which suggests insufficient O2 supply.
在清醒大鼠暴露于5巴高压氧（HBO）60分钟期间，研究了心输出量（CO）的分布情况。连续记录心率（HR）和动脉血压（ABP）。通过微球法在对照期、HBO暴露5分钟和60分钟后测量器官血流量和CO。在对照期和HBO期间均测量动脉酸碱平衡。在HBO期间，动物保持安静，似乎没有应激反应，也没有惊厥迹象。动脉pH值保持在对照水平，而PCO2和HCO3下降（P<0.05）。在HBO期间，收缩压ABP逐渐升高，而平均ABP不变。HR在1巴氧气时开始下降（P<0.05），在加压过程中显著下降（P<0.02），并在HBO期间一直低于对照水平。给予阿托品后，所有动物的HR均升至潜水前对照水平。由于总外周血管阻力增加27%，CO下降了25%。大多数器官的血流量相应地随CO下降，表明血管收缩分布均匀。肾脏、肾上腺和肝脏的血流量未发生变化。右心室和左心室的血流量下降幅度明显大于CO的平均下降幅度。通过收缩压ABP与HR的乘积计算心脏的泵功指数，结果显示心脏功能未变，而左心室血流量下降了50%，这表明氧气供应不足。
