J.Jpn. Surg. Soc.. 62(5): 403-414, 1961

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EXPERIMENTAL AND CLINICAL STUDIES ON HEMODYNAMICS DURING ILEUS, WITH SPECIAL REFERENCE TO CEREBRAL CIRCULATION

PART 1. EXPERIMENTAL INVESTIGATION
Forming a part of the research on ileus in the Matsukura Surgical Clinic, the author made observations on hemodynamics, especially on cerebral circulation during the course of ileus. The results may be summarized as follows :
1. The cerebral blood flow tends to show a slight decrease during the course of ileus, and the decrease becomes greatly intensified at the time of shock.
2. The difference in the oxygen content of the arterial and venous bloods shows a tendency to be augmented during the course of ileus, and this tendency continues to a greater degree during shock, although in some instances a contrary tendency of decrease is experienced.
3. There are no remarkable changes brought about in cerebral oxygen consumption during ileus, but it is greatly reduced during shock.
4. The difference in the glucose content of the arterial and venou blood of the brain shows a temporary increase during ileus but it becomes definitely less at the time of shock.
5. A slight temporary increase is noted in the glucose consumption of the brain during ileus, but during shock a marked decrease occurs.
6. The resistance of cerebral capillaries is reduced during the course of ileus, and it becomes greatly intensified during shock.
7. Almost no changes are seen in circulation time of the cerebarl blood during ileus, but a great delay is seen during shock.
8. Mean arterial blood pressure becomes gradually depressed with the progress of ileus.
9. A marked reduction is seen in the cardiac blood out-put.
10. The circulation time of blood (femoral vein to tongue time) is not remarkably decreased during the early stage of ileus, but it gradually becomes prolonged during its course until it is greatly delayed at the time of shock.
11. Hepatic blood flow decreases gradually from the onset during the course of ileus.
12. A temporary increase in oxygen consumption of internal organs is seen as a general tendency in ileus, but it gradually decreases until the time of shock when it is most remarkable.
13. A remarkable reduction occurs in the circulating blood and plasma volum in parallel with the decreased cardiac out-put and hepatic blood flow. The reduction in the renal blood flow is even more marked from the early stage.
PART 2. CLINICAL INVESTIGATION
The author made clinical observations on hemodynamics with special reference to cerebral circulation in a total of 12 patient treated by operation in the Matsukura Surgical Clinic, including 7 cases of strangulated ileus, 3 of adhesive ileus, one each of intussusception and of obstructive volvulus of the sigmoid colon. The results may be summarized as follows :
1. Cerebral blood flow shows a great reduction in cases with marked depression of mean arterial pressure, but in cases with pressure of over 60 the values are within the normal limits, in good agreement with experimental findings.
2. The difference in the oxygen content of the arterial and venous bloods is intensified in parallel with the depression of mean arterial pressure, but in cases where mean arterial pressure is depressed even to a greater extent this difference may be either intensified or diminished.
3. In many instances the oxygen consumption of the brain lie is the normal range, but it is usually reduced when arterial pressure is depressed.
4. The difference in the glucose content of the arterial and venous blood is usually normal, and this is also the case with glucose consumption of the brain. However, in cases showing a marked depression of mean arterial pressure, the glucose consumption values are also decreased.
5. The alterations in the cerebral circulatory volume seen in patients with ileus before operations all return to their normal values usually on the 7th postoperative day.
6. The circulating blood and plasma volumes, showing some decreases during ileus, reach their normal levels on the 7th postoperative day.
7. Likewise, the cardiac output decreases to a level comparable to the circulating blood volume but it also recovers its normal state on the 7th postoperative day.
8. Hepatic blood flow is reduced even to an extent exceeding that of cardiac outfort in many cases, but it returns to approximately the same level as that of normal value on the 7th postoperative day.
9. Renal blood flow is markedly reduced as a result of lowered blood pressure, but its decrease is even greater than that of cardiac output or hepatic blood flow.
Summarizing the above findings, it may be stated that the various value related to the cerebral circulation in patients with ileus are changed but little as long as blood pressure is maintained, but, when the pressure is lowered, a reduction in cerebral blood flow, a depression of capillary resistance, and a marked diminution of oxygen consumption as well as of glucose consumption of the brain appear. On the contrary, circulating blood and plasma volumes, cardiac output and hepatic blood flow are reduced even in the relatively early stage, the renal blood flow showing especially a remarkable decrease.
Critically examining the results obtained by the experimental and clinical investigations or hemodynamics during the course of ileus as recorded in the foregoing two parts of this paper, the following conclusions may be drawn:
1. In regard to the changes in cerebral blood flow under experimental conditions the reduction in volume is slight at the 30% depression of mean arterial pressure but becomes remarkable at the 50% depression. In clinical cases the fall in cerebral blood flow is not detectable when mean arterial pressure falls only within the 30% limit but a remarkable reductions occurs when the pressure fall over 40%, an observation which agrees well with the results of experimental ileus.
2. The resistance of cerebral vessels decrease according to the course of ileus both in experimental and clinical cases of ileus.
3. Although the difference in oxygen content of the arterial as compared with that of venous blood of the brain tends to increase during the course of ileus experimentally as well as clinically, there are always cases which show a decrease without continuing to increase, when the condition becomes serious with a 40% fall in mean arterial pressure.
4. The oxygen consumption of the brain shows no significant changes during the course of ileus, but it decreases markedly at the time of shock. In clinical cases the values are within the normal range, but they are remarkably depressed in cases where mean arterial pressure is low, thus agreeing well with the result of experimental ileus.
5. The difference in blood glucose content of the arterial as compared with that of the venous blood show a tendency to increase somewhat both in experimental and clinical cases, but it is usually within the normal limits. However, in cases of marked fall in mean arterial pressure, it is remarkably reduced.
6. No remarkable fluctuations in glucose consumption of the brain are noted in both experimental and clinical cases, but in cases of shock, in which mean arterial pressure is greatly depressed, the values of glucose consumption are markedly lowered.
7. Cerebral circulation time is just noticeably shortened during the initial stage of experimental ileus, but with the progress of the condition it becomes gradually prolonged.
8. The fact that circulating blood and plasma volumes gradually become diminished in parallel with cardiac output and hepatic blood flow is observed in both experimental and clinical studies. In clinical as well as experimental cases there is a remarkable reduction in renal blood flow even at the early stage, the former showing somewhat a lesser degree of changes than the latter.
9. On analyzing the changes in circulation time, it is noted that during the early stage of ileus no prolongation can be demonstrated, but it gradually becomes delayed as the condition progresses until the prolongation becomes remarkable at the time of shock is reached.
10. Oxygen consumption of the organs exhibits a marked increase during the early stage in accordance with the progress of the condition in spite of decreased hepatic blood flow, thus demonstrating a means of self-defense on the part of the living organism. However, during the terminal stage there is a marked reduction of oxygen consumption of the organs in conjunction with decreased hepatic blood flow, a phenomenon clearly demonstrating the influence of oxygen lack of the liver.
(Author's abstract)

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