Physiological principles in treatment / by W. Langdon-Brown.

  • Walter Langdon-Brown
Date:
1914
Catalogue details

Licence: Public Domain Mark

Credit: Physiological principles in treatment / by W. Langdon-Brown. Source: Wellcome Collection.

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    controlled by means of the splanchnic area, which, in its turn, is controlled by the vasomotor centre within the cranium. This does not mean that there are no vasomotor nerves in the cerebral vessels—such have been found by Morison and by Gulland — and perfusion of a'drenalin will cause a slight contraction of these vessels. But it is safe to assert that they must play an entirely subsidiary part, and that all the vasomotor effects ordinarily observed can be adequately ex¬ plained without reference to them. To avoid cerebral anaemia, the general blood-pres¬ sure must be kept at a point above the intracranial pressure. This was clearly proved by Cushing, who adopted the method of varying the intracranial pres¬ sure by introducing normal saline solution into the cranial cavity from a pressure-bottle. The effect on the general blood - pressure was observed by means of a tracing taken from the femoral artery. Until the intracranial pressure exceeded the blood-pressure, nothing more than a slight quickening of pulse and respiration occurred, and even this could be avoided if the fluid did not interfere with the sensitive dura. But when that point was reached, the blood-pressure was at once raised until it was again greater than the intracranial pressure. This was repeated with each increase of intracranial pressure until the blood - pressure was forced to a level considerably over 200 millimetres of mercury. Then the vasomotor centre began to show
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