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Anesthesia for Supratentorial Tumors. Pekka O. Talke, MD. Outline. Practical clinical issues only Common cases done by all E1 faculty 4-6 hour cases Numerous ways to provide anesthesia I’ll describe my way (website). Brain Tumors. 35.000 brain tumors/yr 85% primary
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Anesthesia for Supratentorial Tumors • Pekka O. Talke, MD
Outline • Practical clinical issues only • Common cases done by all E1 faculty • 4-6 hour cases • Numerous ways to provide anesthesia • I’ll describe my way (website)
Brain Tumors • 35.000 brain tumors/yr • 85% primary • 60% primary and supratentorial • 15% mets (1/6 of tumors)
Surgeons • Berger • McDermott • Kunwar • Parsa
Anesthetic Goals • Decrease ICP (dural opening, retraction) • Maintain CPP (>70 mmHg) • Prevent cerebral ischemia from retraction • Good operating conditions (NO movement, brain relaxation for exposure) • Rapid awakening at end of case. Delayed awakening >30 min may result into a trip to CT scanner.
Patients, preop • Symptomatic/asymptomatic • Mental status • Location and size of tumor • Intracranial mass effect (increased ICP) • Neurologic deficits and symptoms • Medications (tegretol, dilantin, decadron)
Preop • One IV • Premedicate with up to 2 mg of midazolam if normal mental status. • No premed if altered mental status/risk of increased ICP • Adequate fluid loading (5 to 7 ml/kg of LR)
Induction • Routine monitors • Propofol or thiopental • Fentanyl 5 ug/kg in divided doses prior to intubation • Muscle relaxant (roc). • Hyperventilate spontaneously prior to induction if ICP high. Mild hyperventilation immediately after induction.
Induction cont. • Ceftriaxone 1 gm, 4-10 mg decadron, 1 gm/kg mannitol. • Tape eyes with tagaderms (prep solution) • Temp probe, foley • A-line (ABG, CPP) • Additional IV (limited access, 300 cc blood loss) • Compression stockings
Positioning • Supine, bump, lateral, prone depending on site of tumor • Long cases, lots of padding (pink and blue foam) • Table turned typically 90 degrees • After draping minimal/no access to face (secure ET well)
Maintenance • Control CBF • Good depth of anesthesia • Adequate CPP • Aim for rapid awakening
Maintenance • Oxygen, 70% nitrous oxide • Fentanyl infusion (2ug/kg/hr) (too much-slow awakening) • Inhalation agent (<0.5 MAC Isoflurane) (too much-slow awakening, brain swelling) • Muscle relaxation (vec, panc) • Mild hyperventilation (ET CO2 30-35 mmHg) • Euvolemia (LR, calculation) • Mild hypothermia
Toward the end • First indication of end of surgery when start closing dura (60 min) • Turn fentanyl infusion off • Normalize CO2 once dura closed or earlier if lots of intracranial space • Reduce inhalation agent if possible, and titrate in labetalol
Toward the end cont. • Turn inhalation agent off about 10 min before wakeup • Reverse relaxation once Mayfied pins have been removed • Turn nitrous oxide off at wake up • Average wakeup 5 min
Awakening • Neurosurgical awakening should maintain: • Stable arterial blood pressure and thus cerebral blood flow and intracranial pressure (impaired autoregulation, labetalol) • Stable oxygenation and carbon dioxide tension
Awakening cont. • Neurosurgical awakening should avoid: • Coughing (opioids) • Tracheal suctioning • Airway overpressure during extubation • Hypercarbia, hypoxia (opioids) • Neurosurgical awakening should provide: • Optimal conditions for neurologic examination (opioids, CT)
Recovery • Wake patient up as soon as possible • Extubate if possible • Prevent post op hypertension (bleed). Labetalol • Transport to ICU with monitor and oxygen • Head up position
Potential Complications • Postop seizures • Delayed awakening from anesthesia • Intracranial bleeding • Brain swelling
Tight Brain • Hyperventilate (ET CO2 25-30 mmHg) • Venous drainage (head up, head position) • Relaxation (Intrathoracic pressure low) • Mannitol (320 mOsm/kg) (lasix ?, saline?) • Thiopental • Turn inhalation agents off (propofol/oxygen) • Ventilation (oxygenation) • MAP > 100 mmHg • CSF drainage
Meningiomas • One kind of tumor • May be highly vascular • Frequently embolized preop to reduce bleeding • Potential for blood loss. Ivs
Cortical Motor Mapping • Berger/McDermott/Parsa • No relaxant after craniotomy • No lines on mapped side • O2/nitrous/fentanyl/isoflurane (biases/study) • Keep temp >36 oC (active warming) • Look for movement/EMG • Cold saline/propofol for seizure
SSEP’s • Good baseline is important • Nitrous oxide is bad, inhalation agents are so and so. • Oxygen, fentanyl infusion, propofol (low dose inhalation agent) • Relaxants are OK • Cerebral hypoperfusion-decreased SSEP. Increase MAP (neo)
What’s new? • Euvolemia • Hyperventilation • Temp control • Neuromonitoring/stereotactic navigation
Website • One page descriptions, PDF files • Access from any compurel on the web • Alphabetical • By surgeon • Suggested technique • Please provide feedback to make useful
Surgical Steps • Mayfield pins (stimulation), head positioning • Shaving/prepping/local anesthesia • Draping • Skin incision (stimulation, blood loss) • Scalp off the bone (most stimulation) • Burr holes, sawing • Removing bone/expose dura (ICP high?) • Open dura (need low ICP) • Resect tumor (microscope)
Surgical Steps cont. • Close (30-45 min) • Dura (water tight) • Craniotomy • Scalp and skin • Dressing, remove pins • Time to wake up