Cerebral monitoring

Cerebral monitoring

1. Cerebral monitoring SAMIR EL ANSARY ICU PROFESSOR AIN SHAMS CAIRO

2. The CNS can sometimes be insufficiently monitored leading to grave postoperative complications

3. Classification Cerebral perfusion monitoring . Cerebral metabolism monitoring . Cerebral function monitoring .

4. Cerebral perfusion monitoring Global cerebral perfusion monitoring : Cerebral blood flow measurements. Transcranial Doppler ultrasonography . Near-infrared spectroscopy. Jugular bulb oximetry . Regional cerebral perfusion monitoring : Brain tissue partial oxygen tension monitoring.

5. Global cerebral perfusion monitoring Cerebral blood flow measurements : -Methods : - Kety -Schmidt Inert-gas Saturation Technique. -(TCID) transcerebral double-indicator dilution technique. TCID may become a feasible & clinically useful alternative method fore measurement of global cerebral blood flow.

6. Transcranial Doppler ultrasonography (TCD) : I ts noninvasive , used for the diagnosis of cerebral vasospasm by measurement of blood flow velocity. - <120 or >200 cm/s Transcranial colour -coded sonography

7. Monitors of blood flow dynamics Transcranial doppler Direct, noninvasive measurement of CBF Sound waves transmitted through thin temporal bone contact blood, are reflected, and detected Most easily monitor middle cerebral artery

8. Near-infrared spectroscopy (NIRS) (brain oximetry ) - continuous noninvasive monitoring of cerebral oxygen saturation. - measures arterial , venous & capillary blood oxygen saturation. Accuracy (emitter-detector separation).

9. Jugular bulb oximetry (SjO2) : - continuous invasive monitoring of jugular bulb oxygen saturation - has been applied in neuroanesthesia & neurological intensive care management as an indirect measure of the adequacy of cerebral perfusion.

10. Jugular venous oxygen saturation (SjVO2) The jugular bulb is the dilated portion of the jugular vein just below the base of the skull which contain blood with little extra cerebral contamination. Measurement of oxygen saturation of the jugular bulb provide information about the global oxygenation state of the brain.

11. Regional cerebral perfusion monitoring Brain tissue partial oxygen tension monitoring (PbtO2) : - invasive catheter measures oxygenation in very localized area of the brain - catheter (probe) need guidance to help place into areas of brain by xenon computed tomography or single-photon emission computed tomography. - ischaemia threshold SjvO2 50% = PbtO2 8 mmHg.

12. Major differences : 1. SjvO2 more reduction during hyper ventilation. 2. PbtO2 was more affected by changes in arterial partial oxygen tension. 3. during global ischaemia - PbtO2 decreas to 0 & remained at 0 - SjvO2 initially decreased, but then increased again as cerebral blood flow ceased, & the only blood in the jugular bulb was of extracerebral origin.

13. Cerebral Oximetry (Near infrared spectroscopy) determine cerebral saturation uses a similar principle to pulse oximetry b y using multiple wave lengths of near infrared light , the absorption of this light by oxygenated and deoxygenated haemoglobin determines the overall saturation of the blood present within the brain tissues.

14. Cerebral metabolism monitoring Cerebral microdialysis : - Molecules in the extracellular space extracted & measured. - catheters inserted into the temporal & subfrontal cortex at the end of cerebral aneurysm surgery . - samples extracted & analyzed by microdialysis apparatus (which can analyze glucose, lactate, glutamate, glycerol & urea concentrations within minutes of collection.

15. Revealed that lactate & glutamate appeared to be sensitive markers of impending ischaemia Whereas increased glycerol levels were associated with sever ischaemic deficits .

16. Cerebral function monitoring Bispectral index (BIS). Approximate entropy. Auditory evoked potential (AEP).

17. Bispectral index BIS Is a processed electroencephalographic parameter that is obtained by discriminate analysis of a set of electroencephalographic features. Is known to have a high correlation with clinical signs of anaesthesia & with the concentrations of most hypnotic agents.

18. Bispectral index BIS

19. - is a dimensionless scale from 0 (complete EEG suppression) to 100 (awake). - BIS values of 65-85 have been recommended fore sedation - BIS values of 40-65 have been recommended fore GA - BIS values lower than 40, cortical suppression becomes discernible in raw EEG as a burst suppression pattern.

20. Approximate entropy : BIS + EMG (facial muscle). as a measure of anaesthetic depth.

21. Auditory evoked potential (AEP). Used for measuring hypnotic drug effects. Is better discriminatory power in describing the transition from the conscious to the unconscious state in the individual patient.

22. Ancillary Testing IN BRAIN DEATH

23. Ancillary Testing Nuclear Flow Study (Cerebral Scintigraphy ) Injection of radionuclide tracers are used to establish flow or lack of flow to the brain “Hollow Skull” sign { IN BRAIN DEATH }

24. TCD Transcranial Dopplar Ultrasound used to establish cerebral circulatory arrest Pros: inexpensive, portable Cons: requires an experienced operator and interpreter. 10-20% of patients have inadequate bone windows with which to examine the brain’s circulatory system

25. Eeg: Electroencephalogram

26. EEG Brain tracing of activity, much like the EKG for the heart. Routinely used in Neurology for diagnosing/localizing seizure disorders, sleep disorders No brain activity (flat waves) is diagnostic of brain death

27. Cerebral Angiography BRAIN DEATH

28. Cerebral Angiography Contrast dye study to determine blood flow to the brain Dye is injected into the vessels of the brain by a small catheter Presence of dye = blood flow. Absence of dye = brain death

29. https://www.facebook.com/groups/1451610115129555/#!/groups/1451610115129555/ Wellcome in our new group ..... Dr.SAMIR EL ANSARY

30. GOOD LUCK SAMIR EL ANSARY ICU PROFESSOR AIN SHAMS CAIRO [email protected]