Oral Boards Flashcards
(32 cards)
How are pheochromocytomas diagnosed?
Urinary Tests for neuroendocrine tumors
- Homovanillic and vanillylmandelic acids
- 5-HIAA (5-hydroxyindoleacetic acid) - Byproduct of serotonin
Serum Tests
- Plasma Metanephrines (Highest sensitivity)
Imaging - CT, MRI
What does of Phenoxybenzamine is used for pheo?
A standard protocol for adrenergic blockade is to administer phenoxybenzamine, starting at a dose of 40 mg per day and gradually increasing to 80 to 120 mg per day.
Why should you wait 2 weeks and have alpha blockade for pheo?
Patients with pheochromocytoma are chronically vasoconstricted as a result of the high levels of circulating catecholamines and have a secondary decrease in their blood volume. Preparation for surgery should begin at least 2 weeks prior to allow full alpha-blockade along with gradual restoration of blood volume.
What is a Bezold-Jarisch Reflex?
Cardioinhibitory Mechanoreceptors due to a reduction in preload with a hyperdynamic state
What are the axis of the cerebral autoregulation curve?
Y axis = Cerebral Blood flow
X axis = Mean Arterial Pressure (MAP)
What are some negative consequences of hypothermia?
- Delayed Emergence
- Decresed Drug Metabolism
- Decrease in Cerebral Blood Flow
- Reduced Platelet Function & Activation of Coagulation cascade
- Decreased Blood Flow cutaneously
- Shivering (MVO2, CO)
- Arrythmias
- Decrease in pH
What are the 3 criteria for ARDS?
1.** Timing within 1 week of clinical insult** or new/worsening respiratory symptoms
- Chest XR shows bilateral opacities not fully explained by effusions, lobar/lung collapse, or nodules
- Respiratory failure not fully explained by cardiac failure/fluid overload
For Stabilization of an acute stroke, what are the first immediate steps?
- ABCs
- Establish time of onset (time last seen normal).
- Supplemental oxygen to maintain saturation >94% (hyperoxia may be detrimental in stroke)
- Brain imaging (noncontrast CT scan)
- Neurology Consultation
What are the indications for IV tPA?
- Within 3 hours of symptoms onset (May consider 4.5 hours)
- SBP needs to be ≤185 mmHg and DBP ≤110 mm Hg
Review Contraindications
What are the usual inclusion criteria of Neuro IR mechanical clot extractions?
Indicated for major stroke within 6 hours, due to occlusion of the middle cerebral artery, especially for those with contraindications for intravenous thrombolysis.
What are blood pressure goals during mechanical thrombectomy in neuro IR?
Avoid hypotension: maintain SBP > 140 mm Hg and <180 mm Hg.
What are the first stabilizing factors of neuro IR ruptured aneurysm?
- Secure the Airway
- Oxygenation Increase FiO2 to avoid hypoxia
- Ventilation - Hyperventilate the patient
- Bed Positioning - If possible, elevate head of bed (reverse Trendelenburg)
What medications should be administered if ruptured aneurysm in IR?
- Protamine to reverse Heparin (Discuss with Neuro IR)
- Mannitol (0.25 - 2 gram / kg )
- TIVA
What is blood pressure goal for Neuro IR aneurysm rupture?
Maintain blood pressure near baseline levels until bleeding is controlled.
Once hemostasis is achieved consider increasing BP (SBP 140 - 180 mmHg) to maintain cerebral perfusion pressure in context of increased ICP
What logistically should be called for during aneurysm rupture in IR?
- Neurosurgery for EVD
- Front desk for OR for cranitotomy
- MTP for blood products
What are thee first stabilizing measures for intraopreative aneurysm rupture (Not in Neuro IR)?
- Communicate with the surgeon regarding anticipated blood loss and surgical visibility
- Increse FiO2 (Oxygenate)
- Ventilate (ETCO2 35)
- IV Resuscitation - Initiate vasopressor support, infuse volume
- Call for Blood Products and Potentially MTP
What is the key surgical step that is a “Cross a rubicon step” when doing an aneurysm clipping?
**Opening the Dura
**
Rupture before dural opening vs After Dural Opening during dissection or clip placement
What is the treatment when you have rupture of an intracranial aneurysm before the dura is open?
Rupture before dural opening (IAR mainly occurs during hemodynamic swings and rapid changes in transmural pressure):
- Control abrupt increases in ICP with modest hyperventilation
- FiO2 100%
- Immediate blood pressure control (SBP 140 - 180 mmHg)
- Switch to TIVA (Minimize CMRO2 using IV anesthetic agents including propofol & barbiturates)
- Surgical decompression
- Osmotherapy with mannitol (0.25 - 2 grams / kg) +/- 3% saline (100cc)
What is the treatment of a rupture of aneurysm after the duralhas been open (During dissection or clip placement)?
Rupture after dural opening (IAR mainly occurs during dissection or clip placement):
* Reduce MAPs to ~50s acutely to decrease bleeding, improve visualization and soften aneurysm neck for clipping
* Consider Transient Flow Arrest with Adenosine
* TIVA Minimize CMRO2 using IV anesthetic agents (propofol, barbiturates)
Is Hypothermia warranted for aneurysm rupture?
Hypothermia is not recommended regardless of Hunt and Hess Grade according to the Society for Neuroscience in Anesthesia and Critical Care 2018
What patients are at increased risk of developing autonomic hyperreflexia?
When can the process occur temporally in relation to the injury?
Patients with spinal cord injury at T6 or higher are at increased risk
Can appear 2-3 weeks after injury, typically will manifest within 1 yr
What is the dosing strategy of esmolol?
Bolus dosing vs. Max Dose Infusion
A bolus of 1000 mcg/kg over 30 seconds, followed by 150 mcg/kg per minute infusion, with a max dose of 300 mcg/kg per minute.
A bolus of 500 mcg/kg over 1 minute, followed by 50 mcg/kg per minute infusion for 4 minutes.
If the desired effect is not reached, it may increase in 50 mcg/kg per minute increments until the max dose of 300 mcg/kg per minute. (10-50 mcg/kg/min)
What are the first stabilizing steps of Autonomic Hyperreflexia?
- Immediately inform the surgeon and ask the surgeon to stop operating
- Deepen level of anesthetic
- Increase FiO2 to avoid hypoxia
What is the treatment for autonomic hyperreflexia?
- Nitroglycerin, Nicardipine, or Nitroprusside
- Eliminate stimulus if applicable (i.e. empty bladder or bowel)
- Maintain deeper plane of anesthesia
- Position patient with head up
- Monitor for signs of: MI, hemorrhage, seizure, dysrhythmias (can progress to heart block) and treat accordingly * Consider invasive monitoring
