Effects of norepinephrine and glyceryl trinitrate on cerebral haemodynamics: transcranial Doppler study in healthy volunteers.
Br J Anaesth
; 100(2): 240-4, 2008 Feb.
Article
in En
| MEDLINE
| ID: mdl-18211997
ABSTRACT
BACKGROUND:
The effects of vasoactive substances on cerebral haemodynamics are not fully known. We studied the effects of norepinephrine and glyceryl trinitrate (GTN) on cerebral haemodynamics in healthy volunteers.METHODS:
The effects of norepinephrine (n=10) and GTN (n=10) on the middle cerebral artery flow velocity (MCAFV), cerebral autoregulation, reactivity to carbon dioxide, and estimated cerebral perfusion pressure (eCPP) were studied using transcranial Doppler ultrasound. Established methods were used for calculating zero flow pressure (ZFP). Measurements were made at baseline, and after i.v. infusion of the study drug to the endpoints of 25% increase in mean arterial pressure (MAP) for norepinephrine (0.02-0.1 microg kg(-1) min(-1)), or 15% decrease in MAP for GTN (0.5-2.5 microg kg(-1) min(-1)).RESULTS:
The MCAFV remained unchanged with norepinephrine, but decreased slightly with GTN {from [median (inter-quartile range)] 53 (38, 62) to 48 (33, 52) cm s(-1)}. Cerebrovascular reactivity did not change significantly with either drug. The eCPP did not change significantly with norepinephrine, but increased significantly with GTN [from 49 (32, 54) to 62 (47, 79) mm Hg]. ZFP increased with norepinephrine [from 39 (28, 48) to 56 (46, 62) mm Hg] and decreased with GTN [from 35 (30, 49) to 12 (-7, 20) mm Hg].CONCLUSIONS:
Norepinephrine, despite increasing arterial pressure, did not increase the eCPP. The eCPP increased significantly with GTN, despite decreased MAP. Cerebral vascular tone is an important determinant of CPP during pharmacologically induced changes in arterial pressure.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Vasoconstrictor Agents
/
Vasodilator Agents
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Norepinephrine
/
Cerebrovascular Circulation
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Nitroglycerin
Limits:
Adult
/
Female
/
Humans
/
Male
Language:
En
Journal:
Br J Anaesth
Year:
2008
Document type:
Article
Affiliation country:
Reino Unido