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Raised Intracranial pressure- Control & Effects. Pranava Patil June 2006. www.anaesthesia.co.in anaesthesia.co.in@gmail.com. Intracranial pressure (ICP). Skull- A rigid box Components- Brain+ CSF+ Blood Munro-Kellie doctrine Normal– 5-13 mm Hg
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Raised Intracranial pressure- Control & Effects Pranava Patil June 2006 www.anaesthesia.co.inanaesthesia.co.in@gmail.com
Intracranial pressure (ICP) • Skull- A rigid box • Components- Brain+ CSF+ Blood • Munro-Kellie doctrine • Normal– 5-13 mm Hg • No set point, but levels above 20 mm Hg usually treated
Methods to control ICP Maintenance of Cerebral perfusion pressure (CPP) crucial for favourable outcome • Airway- Intubation • Breathing- Ventilation (sedation, ?Muscle relaxants) PaO2 > 11Kpa PCO2 > 4- 4.5Kpa • Circulation- CPP= MAP-(ICP+CVP) -MAP >90 mm Hg -Facilitate venous drainage -Maintain normovolemia (Avoid 5% dextrose)
…Control of ICP • Dysfunction- GCS, diuretics • Exposure- other injuries, NG/OG tube • Glucose- Tight glycemic control • Monitoring- Invasive BP - CVP - ECG - Saturation - ETCO2 - Urine output • Positioning- Head up 15-20 degrees
…Control of ICP • Temperature- related to CMRO2 -prevent any rise in temp. • Analgesia • Surgical decompression
Use of Drugs • Mannitol - Used in cytotoxic oedema stage - Acts as free radical scavenger - 1mg/kg/24hr of 20% mannitol - Effect seen within 30 mins; lasts for 3-4 hrs - Measure serum osmolality (do NOT give if >330 mosm/lit) • Furosemide -Either used alone or in conjunction with mannitol - Helps restore normal osmolality
Drugs • Barbiturates -reduces Cerebral metabolism,CMRO2, Cerebral blood flow (CBF) -inhibits free radical mediated lipid peroxidation -offer cerebral protection -loading dose- 5mg/kg; -infusion- 3-5mg/kg/hr • Steroids -Used in cerebral oedema caused due to space occupying lesion e.g. tumours -maintain cell integrity
Effects of raised ICP • Reduction in CBF • Coning - Transtentorial - medial temporal lobe pushed below tentorium- compression of corticospinal tracts - Cingulate- one hemisphere pushed under falx cerebri- compression of ant. Cerebral artery - Tonsillar- brain stem herniation thru’ foramen magnum
Signs and Symptoms of raised ICP • Headache • Nausea+/- vomiting • Depressed level of consciousness • Cushings reflex • Respiratory changes- Chyne-Stokes breathing • Pulmonary Oedema • Pupillary changes • Papilledema • CT/ MRI- midline shift, haemorrhage, loss of grey- white differentiation