tailieunhanh - Neurological Emergencies - part 6

Sắt kim loại màu từ các cục máu đông cũng là hoạt động cùng với các loài ôxy phản ứng như vậy. Hiệu ứng mạch máu não tăng huyết áp cấp tính và xuất huyết dưới màng nhện có thể liên quan đến cơ chế gốc tự do gây tổn hại lớp nội mạc. Nonglucocorticoid tương tự steroid methylprednisolone | NEUROLOGICAL EMERGENCIES brain. Ferrous iron from blood clots is also active along with such reactive oxygen species. Cerebrovascular effects of acute hypertension and subarachnoid haemorrhage may involve free radical mechanisms damaging the endothelium. Nonglucocorticoid steroid analogues of methylprednisolone as well as methylprednisolone itself weakly inhibit lipid peroxidation. Tirilazad a 21-amino-steroid is a potent inhibitor of lipid peroxidation and has a vitamin E sparing Various experimental models of head and spinal injury and focal or global ischaemia have shown a variable degree of protection after treatment with Tirilazad or related However large scale clinical trials in head injury 161 stroke 162 and subarachnoid haemorrhage have failed to show 164 Indometacin is a potent cerebral vasoconstrictor and reduces ICP effectively. In five patients with injury with cerebral contusion and oedema in whom it was not possible to control ICP by hyperventilation and barbiturate sedation indometacin bolus injection of 30 mg followed by 30 mg h for seven hours reduced ICP below 20 mmHg for several Cerebral blood flow was reduced at two hours without any changes in cerebral arteriovenous oxygen or lactate differences. Rectal temperature also fell from 38-6 to 37-3 C. However because of the intense vasoconstriction and evidence from primates there is serious concern about the possibility that indometacin will cause ischaemia. Certainly cerebral oxygen delivery is seriously impaired when indometacin is given to very early preterm infants undergoing treatment for patent ductus At present indometacin can only be considered an experimental treatment in head-injured patients. It is interesting that the iron chelator desferrioxamine may be helpful in treating the coma of cerebral malaria and experimental vasogenic oedema. Results in severe head injuries with the oxygen radical scavenger polyethylene glycol .