Effects of intravenous nitroglycerin combined with dopamine on intracranial pressure and cerebral arteriovenous oxygen difference in patients with acute subarachnoid haemorrhage

Pre-Hospital Glyceryl Trinitrate: Potential for Use in Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage is associated with poor clinical outcome and high mortality. Research and treatment modalities have focused on the expansion of the primary hematoma through blood pressure control and activation of coagulation factors. However, clinical trials have failed to show decreased rates of death or disability in intracerebral hemorrhage following hospital initiation of blood pressure control. However, as clinical deterioration often occurs immediately after onset, pre-hospital initiation of blood pressure control may be more ideal.

METHODS

Relevant terms in the National Library of Medicine PubMed database and selected research including basic science, translational reports, meta-analyses, and clinical studies were searched.

RESULTS

Trends indicating improved clinical outcome in intracerebral hemorrhage after hospital-initiated intensive systolic blood pressure control (goal<140 mmHg) have been demonstrated. Statistical significance may not have been obtained because of late treatment times of blood pressure control that approached median 4-6 hours after clinical onset. One trial utilizing glyceryl trinitrate in the pre-hospital setting has been shown to significantly decrease blood pressure within fifteen minutes and improve 90-day clinical outcome.

CONCLUSIONS

Glyceryl trinitrate represents an ideal pre-hospital blood pressure medication because it can be delivered via sublingual or transdermal routes, has a quick and graded onset of action, has neuroprotective effects, maintains cerebral perfusion, and has an established record of safety. As intracerebral hemorrhage requires prompt action to prevent clinical deterioration, more emphasis on pre-hospital therapies for blood pressure reduction will become essential in future therapies.

Pharmacologic Agents in Stroke Prevention, Acute Stroke Therapy, and Interventional Procedures

Pharmaceutical agents have moved far beyond just the aspirin and heparin that were the mainstays of stroke and interventional therapy as recently as 10 to 15 years ago. Our understanding of the mechanisms of thrombus formation and vascular response to damage as well as our armamentarium has tremendously improved in the past decade. Direct thrombin inhibitors, powerful antiplatelet agents, new fibrinolytic agents, and statins now allow far greater manipulation of the intraprocedural and postprocedural clot cascade and atherogenesis. It is mandatory that current-day interventionists understand the correct and appropriate use of these agents to achieve the desired outcomes of therapy.

Brain energy metabolism in the acute stage of experimental subarachnoid haemorrhage: local changes in cerebral glucose utilization

An experimental model was used to investigate acute alterations of cerebral metabolic activity in rats subjected to subarachnoid haemorrhage (SAH). Haemorrhages were produced in anaesthetized animals by injecting 0.3 ml of autologous, arterial nonheparinized blood into the cisterna magna. Control rats received subarachnoid injections of mock-cerebrospinal fluid to study the effect of sudden raised intracranial pressure, or underwent sham operation. Three hours after SAH rats were given an intravenous injection of [14C]-2-deoxyglucose. Experiments were terminated by decapitation, and the brains were removed and frozen. Regional brain metabolic activity was studied by quantitative autoradiography. In comparison with sham-operated controls, cerebral metabolic activity was diffusely decreased after SAH. Statistically significant decreases in metabolic rate were observed in 23 of 27 brain regions studied. Subarachnoid injections of mock-cerebrospinal fluid also produced depression of cerebral metabolic activity, but quantitatively these changes were not as pronounced and diffuse as in SAH rats. The present study shows that a widespread depression of brain metabolism occurs in the acute stage after experimental SAH and is probably secondary to the subarachnoid presence of blood itself and/or blood products.