perk questions

Question 1

HD goals for Pulm HTN

Answer 1

1) Preload - Euvolemic
* RVH -> fixed SV
2) HR - normal to increased + Sinus Rhythm

• RVH -> fixed SV. Therefore CO is HR dependent
• RVH -> dec LV filling 2/2 dec chamber size. Depend on atrial kick for SV

3) SVR - Increased
* maintain CPP via ADP, maintain end organ perfus
4) Contractility - Increased
* Support RV for forward flow of blood
5) PVR - DECREASED

• pulmonary vasodilators
• avoid hypoxia, hypercarbia, hypothermia, symp stim, acidemia

Question 2

Are there other monitors you can utilize beside PAC or CVC to monitor for Pulm HTN?

Answer 2

SaO2, A-a gradient, indicators of end organ hypoperfusion

1) SaO2

• hypoxemia with increasing PVR 2/2 V/Q mismatch and intrapulm shunting
• indicates dec gas exchange

2) A-a gradient

• Intrapulm shunting assoc with inc A-a gradient
• indicates dec gas exchange​

3) end organ perfusion markers

• inc pulm HTN -> dec blood to left side of heart -> dec LVEDV -> dec SV -> dec CO -> end organ hypoperfusion
• UOP, base excess, lactate acidosis, MVSO2, CO, etc…

4) A-line
* hypotension 2/2 dec left side heart filling

Question 3

Mechanism of hyperglycemia induced neurologic insult (2 mech)

Answer 3

1) Promotes lactate acidosis

• stroke patients -> cerebral ischemia -> anaerobic glycolysis -> lactate acidosis production
• Hyperglycemia further provokes anaerobic metabolism, lactic acidosis, and free radical production

2) Cerebral Edema
* disrupting the blood-brain barrier and promoting cerebral edema

Question 4

What are your considerations for IVF and its tonicity for brain sx patients?

Answer 4

Human plasma osmolarity – 285 – 295

= 2[Na+] + [Glucose]/18 + [BUN]/2.8

NS (0.9%) – 308

LR - 275

• Avoid hypo-osmolar solutions (0.45% saline or D5W) -> cerebral edema
• Avoid solutions with glucose -> worsen neurologic injury
• GOAL: Iso-tonic soltuion (LR or 0.9% NS)
  
  • Despite LR being slightly hypotonic (275), there has been nothing to show for worsening neurologic injury (cerebral edema)
  • Not ideal as carrier solution for blood transfusions
• NS - > at risk for hyperchloremic metabolic acidosis
• Consider alternating between NS and LR in a 1:1 ratio

Question 5

What are side effects/risks associated with hyperventilation?

Answer 5

• Cerebral ischemia is PaCO2 less than 30mm Hg
• Alkalosis
• Hypokalemia
• Hypocalcemia
  
  • albumin release H+ ions into plasma, negative charge albumin binds to free calcium -> dec ionized calcium
• Left shift of O2-Hgb curve -> reduce unloading of O2 to tissues

Question 6

Patient has increased UOP following cerebral surgery. How can you differentiate between Mannitol vs cerebral salt wasting vs DI vs Hyperglycemia?

Answer 6

Mannitol

• Consider mannitol and its peak effects and duration of action

CSW

• urine Na+ is high (>100 meq/L),
• plasma – hyponatremia and hypoosmolar
• normal ADH concentration

DI

• urine Na+ is low
• plasma – hypernatremia and hyperosmolar
• dec ADH concentration

Hyperglycemia (DM)

• urine dipstick or urine glucose shows presence of glucose

Question 7

how do you differentiate between SIADH and CSW?

Answer 7

SIADH and CSW - Hyponatremia

SIADH

• inc ADH concentration
• Oliguria
• Urine Na+ < 100 meq/L
• euvolemic or hypervolemic
• Tx: fluid restrict, demeclocycline or vaptan meds (v2 antagonist)

CSW

• normal ADH concentration
• polyuria
• Urine Na+ HIGH (> 100 meq/L)
• hypovolemic
• fluid resuscitate with 0.9% NaCl, consider fludrocortisone

Question 8

What do you tell the family after a child has experienced masseter muscle spasm?

Answer 8

• If patient experiences masseter muscle spasm but does not experience MH, tell family that the patient is MH susceptible. Look at family history as well