Neurosurgery Flashcards
Cushing Response of ICP
Hypertension
Bradycardia
Kussmaul Respirations
Cerebral Edema from BBB disruption
Vasogenic Edema
- most common
- exacerbated in setting of HTN
*tumors, infarct, trauma
Cerebral Edema from cytotoxic edema
Metabolic Causes
- hypoxia, ischemia
- neurons actively extrude Na+
Corticosteroids in edema?
Vasogenic edema from tumors responds well to steroids –> upregulation of tight junctions of BBB
Steroids outside tumors for edema?
worse outcomes
Mannitol in aneurysm cases?
don’t use, it could reduce CSF and cause hematoma or increased transmural pressure and aneurysmal rupture
Posterior Fossa Surgery considerations
- Obstructive Hydrocephalus
- Brain Stem Injury
- Positioning
- Pneumocephalus
- VAE
Monitoring for brain stem injury?
auditory evoked potentials
Venous Air Embolism
occurs when pressure w/i open vein is subatmospheric (usually when incision is above heart)
- entrainment of air can travel to heart and cause CV collpase
When is VAE significant
depends on rate and amount of air entrainment, presence of R->L shunt
*most air is absorbed by lungs, but large air can cause problems
Pathophys of significan VAE
air lock in RV or pulmonary circulation leads to decreased R-side CO and subsequent L-side CO
Signs of VAE
- drop in EtCO2
- increase PaCO2
- hypotension
- tachycardia
- stroke
Monitors of VAE
- TEE - best
- Precordial doppler
- EKG
- Capnography
Treatment of VAE
- Notify surgeons -> flood field (ID entry site)
- FiO2 100%
- Head down (if possible)
- Vasopressors + fluid
- Aspirate CVC
- Bilateral jugular compression
- +/- PEEP
- ACLS
Goals in head trauma
Avoid hypoxia, hypercapnia and hypotension at all costs
- ICP concerns
- maintain cerebral perfusion
- NO STEROIDS*
- NO ALBUMIN*
Neurogenic pulmonary edema
massive sympathetic discharge from increased ICP –> Severe pulmonary vascular congestion and alveolar hemorrhage
Ruptured Cerebral Aneurysm timeline
sudden, severe WHOL
- rebleed w/i 24-48 hrs
- vasospasm w/i 72 hrs - 5 days
Vasospasm treatment
Nimodipine ppx
- hydrate, ensure blood pressure
- intraarterial vasospastic agents
What to do if aneursym ruptures in OR?
- adenosine or propofol bolus
- cooling the patient
- resuscitating the patient
Acute Spinal Cord Injury
can cause sympathectomy with unopposed parasympathetic activity leading to drastically hemodynamic derangements during stimulating parts (laryngoscopy, suction, extubation)
how long post-stroke should you wait for surgery?
Atleast 2 weeks –> altered blood flow and metabolic rate
- altered responsiveness to CO2 and BBB
fluid disorders s/p neurosurgery
SIADH
Cerebral Salt Wasting
Diabetes Insipidus
SIADH exam
hyponatremic
euvolemic
lots of urine sodium
CSW exam
hyponatremic
hypovolemic
high urine sodium
DI exam
hypernatremic
hypovolemic
Dilute urine - LOTS of urine
Common anesthetic drugs that lower seizure threshold?
ketamine, methohexital, atra and cisatracurium
Hematologic effect of antiepileptics?
MOST AED alter coagulation factors….watch for bleeding
Parkinson Disease
progressive loss of DA neurons in nigrostriatum
increase in GABA in basal ganglia –> inhibits thalamic nuclei and blocks the motor cortex
Parkinson symptoms
bradykinesia, rigidity, postural hypotension, sensitivity to anesthetics
Anesthetic concerns w/ Parkinson
continue med pre and intraop!
- avoid anti-dopamine meds –> worsen rigidity (droperidol and metocloperamide)
Multiple Sclerosis
reversible demyelination of brain and SC (random)
Anesthetic concerns w/ MS
- avoid elective surgery during flare
- stress of surgery can flare
- peripheral nerve blocks ok, neuraxial less so
- avoid sux
- maintain good room temp
Amyotropic Lateral Sclerosis
disease of upper and lower motor neurons
super-oxide dismutase 1
ALS anesthetic concerns
affects all muscles!!!
- respiratory and swallowing
- avoid sux
- no neuraxial
Guillan Barre
sudden ascending motor paralysis and areflexia w/ variable paresthesias
- immune disease of myelin sheath
Levels of acute spinal cord injury and complications
T1 = quadriplegia L4 = paraplegia
