NEW YORK (Reuters Health) – In patients with poor-grade subarachnoid hemorrhage, hypertonic saline improves cerebral blood flow and enhances cerebral tissue oxygenation for 4 hours post-infusion, UK researchers report in the January issue of Stroke.

“Death and disability following severe subarachnoid hemorrhage is associated with low cerebral blood flow and cerebral oxygenation, causing brain ischemia and subsequent stroke,” lead author Pippa G. Al-Rawi told Reuters Health by email.

The present study, she pointed out, indicates that hypertonic saline causes a sustained improvement in brain tissue oxygenation, which in turn is linked to improved clinical outcomes.

In their investigation, Al-Rawi and colleagues at Addenbrooke’s Hospital, Cambridge, treated 44 patients with 2 mL/kg of 23.5% saline.

Thirty minutes later, there were significant increases in arterial blood pressure, cerebral perfusion pressure, flow velocity, brain tissue pH, and brain tissue oxygen. There was also a significant decrease in intracranial pressure.

The significant increase in brain tissue oxygen lasted for 4 hours. Also, the effect on intracranial pressure persisted for more than 5 hours, and on flow velocity it persisted for more than 4 hours.

Following infusion of hypertonic saline, cerebral blood flow rose by an average of 20.3%.

Thirty-six percent of the cohort had favorable outcomes (modified Rankin scale score of 1 to 3). Compared to the 64% of patients with unfavorable clinical outcomes, those with favorable outcomes had increased cerebral blood flow, brain tissue oxygen and pH, and reduced intracranial pressure.

In fact, increases in brain tissue oxygen that lasted for more than 210 minutes were significantly associated with favorable outcomes, the authors report.

“This study,” the researchers conclude, “demonstrates that the increase in cerebral blood flow seen after hypertonic saline therapy is not a simple washthrough effect, but improves oxygen delivery to poorly perfused areas.”

Al-Rawi added that “further work is still needed, but given the relatively long-lasting action of hypertonic saline, the clinical aim would be to improve areas of low blood flow in the early vulnerable period whilst awaiting spontaneous recovery of cerebral blood flow.”

Reference:
Stroke 2010;41:122-128.