Effect of mannitol on brain metabolism and tissue oxygenation in severe haemorrhagic stroke.
BACKGROUND
The impact of osmotic therapies on brain metabolism has not been extensively studied in humans. The authors examined if mannitol treatment of raised intracranial pressure will result in an improvement in brain metabolism together with the expected drop in intracranial pressure (ICP).


METHODS
This is a retrospective review of prospectively collected data. Twenty episodes of raised ICP (>20 mm Hg) resistant to standard therapy that required infusions of mannitol were studied in 12 comatose patients with multimodality monitoring including ICP, PbtO(2) and microdialysis. The authors compared mean arterial blood pressure, ICP, cerebral perfusion pressure, PbtO(2), brain lactate, pyruvate and glucose using cerebral microdialysis, for 3 h preceding and 4 h after hyperosmolar therapy. Time-series data were analysed using a multivariable general linear model utilising generalised estimating equations for model estimation to account for within-subjects and between-subjects variations over time.


RESULTS
20% mannitol solution (1 g/kg) was administered at the discretion of the attending neurointensivist. ICP decreased 30 min (from 27 ± 13 to 19 ± 16 mm Hg, p<0.001) and cerebral perfusion pressure increased 45 min (from 73 ± 18 to 85 ± 22 mm Hg, p=0.002) after the start of mannitol infusions, whereas mean arterial blood pressure and PbtO(2) did not change significantly. The peak lactate-pyruvate ratio was recorded at the time of initiating osmotherapy (44 ± 20) with an 18% decrease over 2 h following mannitol therapy (35 ± 16; p=0.002). Brain glucose remained unaffected.


CONCLUSIONS
Mannitol effectively reduces ICP and appeared to benefit brain metabolism as measured by the lactate-pyruvate ratio.
Helbok
Raimund
R
Division of Neurocritical Care, Department of Neurology, Columbia University Medical Center, Milstein Hospital 8-300 Center, New York, NY 10032, USA.
Kurtz
Pedro
P
Schmidt
J Michael
JM
Stuart
R Morgan
RM
Fernandez
Luis
L
Malhotra
Rishi
R
Presciutti
Mary
M
Ostapkovich
Noeleen D
ND
Connolly
E Sander
ES
Lee
Kiwon
K
Badjatia
Neeraj
N
Mayer
Stephan A
SA
Claassen
Jan
J
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism*; D004234:Diuretics, Osmotic / Q000627:therapeutic use; D005260:Female; D015600:Glasgow Coma Scale; D005947:Glucose / Q000378:metabolism; D006801:Humans; D020300:Intracranial Hemorrhages / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism*; D007427:Intracranial Pressure / Q000187:drug effects; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D008353:Mannitol / Q000627:therapeutic use*; D017551:Microdialysis; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D019289:Pyruvic Acid / Q000378:metabolism; D012189:Retrospective Studies; D020521:Stroke / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism*
D004234:Diuretics, Osmotic; D019344:Lactic Acid; D008353:Mannitol; D019289:Pyruvic Acid; D005947:Glucose; D010100:Oxygen