Changes in the requirements for blood transfusion in brain surgery.

The amount of blood used in transfusions during certain neurosurgical operations was less in 1978-79 than in 1971-72 and in 1965-66. The operations investigated were for gliomas and meningiomas of the brain, pituitary adenomas, acoustic neurinomas, arteriovenous malformations, and arterial aneurysms. The major change in anaesthetic techniques between 1965-66 and 1971-72 was the introduction of hypocapnia by controlled artificial hyperventilation. We suggest that this was the main factor responsible for the reduction in the need for blood transfusions. The avoidance of halothane, the use of induced hypotension, and microsurgical technique may have been responsible for the smaller drop between 1971-72 and 1978-79. Good neurosurgical anaesthesia demands anaesthetic expertise, reliable apparatus, and instant laboratory service, but may also reduce costs by reducing the need for blood transfusions.