Hyperosmolar Solutions Effects on Cerebral Oxygenation and Metabolism

Abstract

Purpose: To estimate the dynamics of cerebral oxygenation and metabolism during intracranial pressure (ICP) correction with 15% Mannitol and 7,2% saline in 6% HES 200/0,5. Methods: We analyzed 39 episodes of ICP correction with 15% Mannitol or 7,2% NaCl in 6% HES 200/0,5 ("Hyper- HAES") in 9 patients with intracranial hemorrhage (GCS 4-8). Monitoring of ICP, systemic hemodynamics, SvjO2 and cerebral microdialysis was used in all patients. Brain temperature (Tbr) and brain oxygen tension (PbrO2) were investi- gated in 5 patients. ICP > 20 mmHg was the indication for treatment. Results: The duration of ICP reduction below 20 mmHg was 121 ± 58 min for 15% Mannitol and 258 ± 122 min for "Hy- perHAES" (p<0,001). Administration of the investigated solutions was associated with slight PbrO2 increase. 15% Manni- tol infusion did not change brain metabolism in "intact" and "lesioned" tissue. HyperHAES administration was accompa- nied with significant increase of glucose and pyruvate concentration in "intact" and "lesioned" brain tissue. We observed the same dynamics of cerebral oxygenation and metabolism in patients with traumatic and nontraumatic intracerebral hemorrhage. Infusion of investigated solutions was not accompanied by significant dynamics of cardiac preload and func- tion. Conclusions: "HyperHAES" infusion results in prolong ICP reduction than 15% Mannitol and is accompanied with slight increase of PbrO2 and significant improvement of cerebral metabolism. 15% Mannitol administration does not influence cerebral oxygenation and metabolism. 15% Mannitol and "HyperHAES" infusion does not influence systemic hemody- namics in normovolemic patients. Brain lesion, caused by intracranial hemorrhage may be accompanied by mitochondrial dysfunction, characterized by reduction and even enlargement of lactate/pyruvate ratio in condition of sufficient oxygen and glucose delivery to the brain.