Cerebral Physiology Flashcards
(41 cards)
Metabolic rate of braine
12_15% of cardiac output
Cerebral blood flow (CBF)
50 ml/100 g/min
80% gray matter / 20% white matter
How much of the brain energy consaption supports electrophysiologic function ?
60%
Neurovascular coupling of brain
Increase cerebral activity (metabolism) ⇒ Increase CBF
CBF autoregulated over MAP range
65-150 mmHg
Chemical regulation of CBF
1) PaCO2 25-70 mmHg - CPF in normal range
2) If PaO2 less then 60 mmHg ⇒CBF increase dramatically
3) Reduction of body temperature ⇒suppression of cerebral metabolism
Systemic vasodilatators and, CBF
Nstronglyarein, nitroprusside, hydroxyzine and Ca channel blockers ⇒vasodilate the cerebral circulation (depending on the MAP )
Wave frequency of AWAKE
1) beta-activity
2)16-30Hz
Stage-1 NREM sleep /
1) Alfa
2) 7,5-11Hz
stage-2 NREM sleep
) theta wave
2) 4.5.7.5 Hz
3) sleep spindle and K-complex
stage3 NREM sleep
^) 4 Hz
2) Delta
REM - sleep
1) Theta wave
Global CBF
45-55 ml/100g/min
Cortical CBF
75-80 ml/100g/min
Subcortical CBF
8-20 ml/100g/min
Cerebral metabolic rate of oxygen (CMRO2)
3-3.5 ml/100g/min
Cerebral vascular resistance (CVR)
1.5-2.1 mmHg/100g/min/ml
ICP
8-12 mmHg
Cerebral venous PO2
32-44 mmHg
Cerebral venous SO2
55-70%
Jugular venous oxygen saturation
60-70%
Total CSF space
150 ml
Total daily CSF production
450 ml
Contraindications to thrombolysis
1)inability to identify onset of symptoms,
2) intracranial hemorrhage,
3) previous stroke or head trauma within 3 months,
4)recent intracranial or spinal surgery,
5) gastrointestinal malignancy or bleeding,
6) coagulopathy.