TY - JOUR
T1 - Effect of mannitol on cerebral blood volume in patients with head injury
AU - Diringer, Michael N.
AU - Scalfani, Michael T.
AU - Zazulia, Allyson R.
AU - Videen, Tom O.
AU - Dhar, Rajat
AU - Powers, William J.
PY - 2012/5
Y1 - 2012/5
N2 - BACKGROUND: Mannitol has traditionally been the mainstay of medical therapy for intracranial hypertension in patients with head injury. We previously demonstrated that mannitol reduces brain volume in patients with cerebral edema, although whether this occurs because of a reduction in brain water, blood volume, or both remains poorly understood. OBJECTIVE: To test the hypothesis that mannitol acts by lowering blood viscosity leading to reflex vasoconstriction and a fall in cerebral blood volume (CBV). METHODS: We used O positron emission tomography to study 6 patients with traumatic brain injuries requiring treatment for intracranial hypertension. Cerebral blood flow (CBF), CBV, and cerebral metabolic rate for oxygen (CMRO2) were measured before and 1 hour after administration of 1.0 g/kg 20% mannitol. RESULTS: CBV rose from 4.1 ± 0.4 to 4.2 ± 0.2 mL/100 g (P =.3), while intracranial pressure fell from 21.5± 4.9 to 13.7 ± 5.1 mm Hg (P <.003) after mannitol. Blood pressure, PaCO2, oxygen content, CBF, and CMRO2 did not change. CONCLUSION: A single bolus of 1 g/kg of 20% mannitol does not acutely lower CBV. Another mechanism, such as a reduction in brain water, may better explain mannitol's ability to lower intracranial pressure and reduce mass effect.
AB - BACKGROUND: Mannitol has traditionally been the mainstay of medical therapy for intracranial hypertension in patients with head injury. We previously demonstrated that mannitol reduces brain volume in patients with cerebral edema, although whether this occurs because of a reduction in brain water, blood volume, or both remains poorly understood. OBJECTIVE: To test the hypothesis that mannitol acts by lowering blood viscosity leading to reflex vasoconstriction and a fall in cerebral blood volume (CBV). METHODS: We used O positron emission tomography to study 6 patients with traumatic brain injuries requiring treatment for intracranial hypertension. Cerebral blood flow (CBF), CBV, and cerebral metabolic rate for oxygen (CMRO2) were measured before and 1 hour after administration of 1.0 g/kg 20% mannitol. RESULTS: CBV rose from 4.1 ± 0.4 to 4.2 ± 0.2 mL/100 g (P =.3), while intracranial pressure fell from 21.5± 4.9 to 13.7 ± 5.1 mm Hg (P <.003) after mannitol. Blood pressure, PaCO2, oxygen content, CBF, and CMRO2 did not change. CONCLUSION: A single bolus of 1 g/kg of 20% mannitol does not acutely lower CBV. Another mechanism, such as a reduction in brain water, may better explain mannitol's ability to lower intracranial pressure and reduce mass effect.
KW - Cerebral blood flow
KW - Cerebral blood volume
KW - Mannitol
KW - Osmotic
UR - http://www.scopus.com/inward/record.url?scp=84860263239&partnerID=8YFLogxK
U2 - 10.1227/NEU.0b013e3182417bc2
DO - 10.1227/NEU.0b013e3182417bc2
M3 - Article
C2 - 22089753
AN - SCOPUS:84860263239
SN - 0148-396X
VL - 70
SP - 1215
EP - 1218
JO - Neurosurgery
JF - Neurosurgery
IS - 5
ER -