Cerebral Physiology Flashcards
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.
Cerebral blood Volume
5 ml/100 g
systolic BP for traumatic brain injury
- 15-49 > 110
- 50-69>100
- > 70 > 110
Systolic blood pressure for aneurysmal subarachnoid hemorrhage
1) unsecured < 160
2) vesospasm bp>
Blood pressure after cardiac arrest
1) SBP >90 mmHg
2) MAP> 65 mmHg
Blood pressure for acute ischemic stroke without revascularization
Up to 220/120 mmHg
Blood pressure for acute ischemic stroke with attempted revascularization
1) PretPA / mechanical thrombectomy <185/110
2) 24hours after tPA, during mechanical thrombectomy, incomplete thrombectomy<180/105
3) Post successful mechanical thrombectomy (2 /3 vascular territory) <140
Systolic BP for Intracranial hemorrage
130-150 MmHg
Central circulation is impair after acute stroke
2 weeks
Restoration of autoregulation after acute stroke
1-3 month
Effects of anesthetic agent on the rate of CST secretion
1) reduces Halotane, etomidate
2) increase Enflurane, desflurane
Effects of anesthetic agent on the rate of CSF absorbtion
1) increase Isoflurane, fentanyl, etomidate
2) decrease halothane , enflurane
Which gas potentially epileptogenic
Enflurane
wich anesthetic potentially epileptogenic ? .
Etomidate
Effects hypothermia for CMR
Decrease by 6-7% per degree Celsius
CBF with PaCO2
1-2ml/100g/min