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NS8 Neurosurgery
Treatment of Elevated ICP
ICP HEAD
Intubate
Calm (sedate)/Coma Place drain/Paralysis Hyperventilate Elevate head Adequate BP Diuretic (mannitol)
Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension
N Engl J Med 2016;375:1119-30
Methods: RCT comparing decompressive craniectomy to barbiturate coma and medical management in 400 patients with TBI and refractory intracranial hypertension. Primary outcome was Extended Glasgow Outcome Scale at 6 months. Results: Patients treated with decompressive craniectomy had lower mortality rates (26.9% vs. 48.9%) but higher rates of disability (8.5% v. 2.1% lower severe disability, 21.9% v. 14.4% upper severe disability, 15.4% v. 8.0% moderate disability). Conclusion: Compared to medical care, decompressive craniectomy in patients with TBI and refractory intracranial hypertension results in lower mortality and higher rates of vegetative state and severe disability.
Idiopathic Intracranial Hypertension Toronto Notes 2019 Treatment of Elevated ICP
• treatmentprinciple:treatprimaryetiology(i.e.removemasslesions,ensureadequateventilationfor example in ARDS)
• ifelevatedICPpersistsfollowingtreatmentofprimarycause,considertherapywhenICP>20mmHg
• targets:ICP<22mmHg,CPP60-70mmHg,sBP>100(age50-69)or>110(age<50or>70)mmHg
(individualize targets based on patient's clinical picture and progression)
Table 5. Management of Elevated ICP
Consideration
Conservative Measures
Position
Fever Management
Prevent Hypotension Normocarbia Adequate O2 Osmolar Diuresis
Corticosteroids
Aggressive Measures
Sedation
Paralysis
Barbiturate-Induced Coma (refractory ICP)
Hyperventilate Drain CSF Decompression
Intervention
Elevate head of bed at 30° Maintain neck in neutral position
Acetaminophen or mechanical cooling
PRN: fluid, vasopressors, dopamine, norepinephrine
Ventilate to pCO2 35-40 mmHg
Target pO2 >60 mmHg
Mannitol 20% IV solution 1-1.5 g/kg, then 0.25 g/kg q6h to serum osmolarity of 315-320
Acts in 15-30 min, maintain sBP >100 mmHg
3% hypertonic saline comparable to mannitol
Dexamethasone
Usually Propofol
Others: barbituates/codeine, or fentanyl/MgSO4 Light = barbituates/codeine
Heavy = fentanyl/MgSO4
Vecuronium
Phentobarbital 10 mg/kg over 30 min, then 1 mg/kg q1h continuous infusion
Target pCO2 30-35 mmHg
Avoid within 24 h following trauma
Insert EVD (if acute) or shunt Drain 3-5 mL CSF
Decompressive craniectomy
Rationale
Increases
1. Jugular venous patency
2. intracranial venous outflow with minimal effect on MAP
Decrease metabolic demands to decrease CBF and minimize brain injury
Maintains CBF
Prevents vasodilatation
Prevents hypoxic brain injury
Increase serum tonicity → osmotically drives fluid out of brain
Decrease vasogenic edema over subsequent days around brain tumour, abscess, blood
No proven value in head injury or stroke
Reduces sympathetic tone
Reduces HTN induced by muscle contraction
Reduces sympathetic tone
Reduces HTN induced by muscle contraction
Reduce CBF and metabolism
Decreases mortality, but no affect on neurologic outcome No role for the use of hypothermia in head injury
Decreases CBF and thus ICP but use for brief periods only Reduces intracranial volume
Allows brain to swell while reducing risk of herniation
Modified Dandy's Criteria
1. Symptoms of raised ICP
2. No localizing signs except sixth nerve palsy 3. Patient awake and alert
4. Normal neuroimaging without evidence of
thrombosis
5. LP opening pressure >25 cm H2O, normal
CSF
6. No better explanation for raised ICP
Idiopathic Intracranial Hypertension
(Pseudotumour Cerebri)
Definition
• raisedICPwithpapilledema,butwithout:mass,hydrocephalus,infection,orhypertensive encephalopathy (diagnosis of exclusion)
• diagnosedbymodifiedDandy'scriteria
Etiology
• unknown(majority),butassociatedwith:
■ dural sinus thrombosis
■ habitus/diet: obesity, hypervitaminosis A
■ endocrine: reproductive age, menstrual irregularities, Addison’s/Cushing’s disease
■ hematologic: iron deficiency anemia, polycythemia vera
■ drugs: steroid withdrawal, tetracycline, amiodarone, lithium, nalidixic acid, oral contraceptive,
growth hormone, retinoids
• riskfactorsoverlapwiththoseofvenoussinusthrombosis;similartothoseforgallstones(“fat,female,
fertile, forties”)
Epidemiology
• incidence:generalpopulation~1-2/100,000/yr;obesewomenofchildbearingage19-21/100,000
Clinical Features
• symptoms:H/Ain>90%,nausea,transientvisualobscurations,pulsatiletinnitus,diplopiacanoccur with CN VI palsy, neck/back pain
• signs:CNVIpalsycanoccur(otherwisenoneurologicdeficits),visualacuityandfielddeficits, papilledema, optic atrophy