Adrenal #2 Flashcards
What is a pheochromocytoma?
- Catecholamine secreting tumor of the adrenal medulla
- Originates in adrenal medulla and is related to tissues elsewhere in the body
- >95% found in abdominal cavity
- 90% originate in adrenal medulla
- 10% involve both adrenal glands
- functional tumors in multiple sites are present in 20% of patients, especially children
- most common in young to mid adult
What are the predominant symptoms of pheochromocytoma?
the associated symptoms?
- Predominant symptoms:
- HTN- continuous or paroxysmal
- HA
- Diaphoresis/Pallor
- Palpitations/tachycardia
- Associated symptoms:
- orthostatic hypotension
- anxiety
- tremor
- chest pain
- epigastric pain
- flushing
What is the duration and frequency of pheochromocytoma episodes?
- Duration- one hour or less
- frequency- daily to once every few months
How is Pheochromocytoma diagnosed?
- Urine tests- useful for screening but unreliable for definitive diagnosis
- Plasma levels
- reliably reflects the presence of Pheo
- done by measuring the amount of free plasma metanephrines
- Normatanephrine >400 pg/ml (metabolite of NE)
- Metanephrine >220 pg/ml (metabolite of Epi)
- CT/MRI to locate tumor
How is pheochromocytoma treated?
- Surgical excision
- VERY difficult to manage in the OR
- restore intravascular volume pre-op
- phenoxybenzamine (alpha 1&2 block- longer acting) or Prazosin (alpha 1 block- shorter acting)
- restore release of insulin with alpha block
- may go right up to day of surgery, may stop a few days before–depending on provider
- Beta block (esmolol) if persistant tachy occurs
In a pt with pheochromocytoma, do you Beta block or Alpha block first?
- Alpha block first
- If you BB first, the decrease HR and contractility will make it impossible for the heart to pump blood agains the constricted smooth muscle vasculature
- unable to maintain CO
What can be optimized/worked up in a patient with pheochromocytoma?
- Cardiac work up- increased PVR can lead to myocardial ischemia, ventricular hypertrophy, CHF, cardiomyopathy
- Hyperglycemia- will have decreased circulating insulin with increased glycogenolysis
What are the pre-op criteria for a pt with pheochromocytoma?
- BP < 165/90 for 48 hours prior to surgery
- BP upon standing should not be <80/45
- ECG should have no ST-T wave changes unless they are permanent
- No more than 1 PVC q 5 minutes
What are anesthetic considerations for a pateitn with pheochromocytoma?
- Must have good communication with the surgeon
- must be warned if they are about to manipulate the tumor
- Continue adrenergic blockade
- be prepared for hypo OR hypertension
- Fluid management
- prehydrate to prevent hypovolemia
- May have a falsely elevated HCT, get a type and cross
- Assess renal function
- Have a fluid replacement plan!
- BIG iv! At least 2!
What medications/anesthetic technique would you use for a pt with pheochromocytoma?
- Heavy premedication with benzos and opioids
- Anesthetic:
- combined GA/continuous lumbar epidural
- O2/air/Sevo or Des
- 1.5-2 MAC
- muscle relaxant: Vec or Roc
- Epidural prior to induction
- Invasive monitoring: Aline, CVL, Swan if there is extensive cardiac effects
- combined GA/continuous lumbar epidural
- Prepare for hyperdynamic BP
- lidocaine- 1-2 mg/kg
- Opioid (avoid histamine!)
- sufentanil 0.5-1 mcg/kg
- Fentanyl 3-5 mcg/kg
- Propofol 3 mg/kg
What do you need to prevent during induction of a patient with pheochromocytoma?
What drugs should you have ready, in line, with the pump already programmed?
- SNS response to DVL
- Licocaine 1-2 mg/kg
- Fantanyl 100-200 mcg or Sufentanil 10-20 mcg
- Ready drugs:
- Nitroprusside 1-2 mcg/kg
- Phentolamine
- Esmolol
How can BP be controlled in Pheochromocytoma?
HR?
- BP:
- Nitroprusside (preferred)
- Phentolamine- tachyphylaxis, tachycardia and longer duration
- Magnesium sulfate- inhibits catecholamine release from adrenal medulla
- CCB
- HR
- Esmolol (preferred)
- Labetalol
- Metoprolo
What should you expect to happen as the surgeon is ligating the tumor’s venous drainage?
- decrease release of catechols–prepare for hypotension
- stopy antihypertensives
- decrease concentration of VA
- Give volume first!
- administer pressors
- phenylephrine
- NE
- Dopamine
- *persistant hypotension may require an infusion of NE until the vasculature can adapt to decreased levels of alpha stimulation
What drugs should be avoided in a pt with pheochromocytoma?
- Histamine releasers: Morphine, meperidine, atracurium
- Halothane- sensitizes myocardium to epi
- succinylcholine- fasciculations of abdominal muscles may cause release of catecholes from tumor
- Pancuronium
- atropine
- metoclopramide- causes catechol release?
What are the post operative considerations for a patient with pheochromocytoma?
- Analgesia
- 50% of patients will remain hypertensive
- elevated catecholamine levels for 10 days postoperatively
- continue antihypertensive therapy
- Usually can extubate early- young with no lung problems
- hypoglycemia from excess insulin release and ineffective lipolysis and glycogenolysis
- Steroid supplementation- for bilateral adrenalectomies or hypoadrenalism
- postoperative HTN
- presence of occult tumors
- volume overload
- continue monitoring