Pretest_1 Flashcards
Loss of the ileum (eg jejunoileal bypass, or functional loss as in Crohn’s) predisposes to what?
hyperoxaluria and calcium oxalate stones!
Normally, calcium and oxalate bind in the bowel and are excreted. Unabsorbed fatty acids and bile acids combine with calcium, enabling the uptake of oxalate. The oxalate is then secreted in the kidney, where it can combine with calcium to form stones.
How do you calculate FENa?
(urine sodium x serum creatinine) / (urine creatinine x serum sodium)
Which values support a prerenal etiology for oliguria?
- FENa
- Urine sodium
- Urine osmolality
- BUN/Cr
- Urine Cr / Serum Cr
- FENa < 1% –> (UrNaxSCr)/(UrCrxSNa)
- Urine sodium < 20mEq/L
- Urine oxmolality > 500 mOsm/kg
- BUN/Cr > 20
- Urine/Serum (Cr) >20
Since both hypomagnesemia and hypocalcemia have similar neurological effects (paresthesias, hyperreflexia, muscle spasm, tetatny), how can you differentiate between them?
EKG! Hypocalcemia leads to prolonged QT and TWI; Hypomagnesemia more like hypercalcemia cardiac wise (ST segment depression, flattening of p waves)
According to Goldman’s criteria, an MI within ___ months of surgery is considered to increase a patient’s risk for cardiac complication after surgery.
6
A history of tinnitus in conjunction with mixed metabolic acidosis-respiratory alkalosis is pathognomonic for
salicyclate intoxication
Heparin-induced thrombocyotpenia (HIT) is mediated by antibodies to complexes formed by binding heparin to ______________
platelet factor 4
How is HIT treated?
Use of a non-heparin anticoagulant (like lepirudin or ragatroban, which are both direct thrombin inhibitors) with conversion to oral warfarin when platelet count back above 100K
When do most perioperative infarcts occur?
Around the third postoperative day, when the third-space fluids return to the circulation, which increases the preload and myocardial oxygen consumption.
What is the treatment of mesenteric ischemia?
Initially: increase cardiac output and blood pressure. Celiotomy (aka laparotomy) is required once diagnosis of arterial occlusion or bowel infarction has been made or if peritoneal signs develop.
What is von willebrand factor?
a stimulus for platelet aggregation and a carrier protein for circulating factor VIII
How is von Willebrand disease treated?
Do not generally require treatment unless need surgery or are severely injured.
1) DDAVP which results in normalization of factor VIII activities by boosting the release of vWF
2) Cryoprecipitate (provides vWF)
Why does DDAVP only help with Type I and Type II vWD?
DDAVP, a synthetic analogue of vasopressin, activates receptors that result in release of vWF from storage sites and increases levels of factor 8 as well. (helps with Type I and Type II, which is marked by decreased and defective vWF; Type III is absent).
A diagnosis of SIRS involves 2 or more of which 4 criteria?
1) T>38C or T< 36
2) HR > 90
3) RR>20 or PaCO2 < 32
4) WBC >12, WBC < 4, or >10% bands (immature neutrophils)
Why do large amount of banked blood transfusions lead to coagulopathy?
What is the treatment?
Dilutional thrombocytopenia and deficiencies in factors V and VIII.
Treatment = FFP and platelets
When do the components of the GI system start to function again following surgery?
1) stomach
2) small bowel
3) colon
1) stomach: 24 hrs
2) small bowel: within hrs
3) colon: 3-4 days
What is refeeding syndrome? What electrolytes are affected?
Hypokalemia, hypomagnesemia, hypophosphatemia, resulting from reshift of electrolytes BCK into the intracellular space (after being shifted extracellularly during periods of starvation)
What are early complications of TPN? (x4)
1) hyperglycemia
2) refeeding syndrome (hypokalemia, hypomagnesemia, hypophosphatemia)
3) hyperchloremic acidosis
4) volume overload with resultant heart failure
Severe stress, infection, trauma, or abrupt cessation/too rapid tapering of chronic glucocorticoid therapy can lead to _________, which is classically manifested by which symptoms?
How can it be distinguished from sepsis?
acute adrenal insufficiency:
1) changing mental status
2) increased temperature
3) cardiovascular collapse
4) hypoglycemia
5) hyperkalemia
Sepsis usually has hyperglycemia and no change in potassium
When should FFP be transfused to minimize bleeding due to surgery?
WHen the patient is called to the operating room (half life is 4 to 6 hours; should cover surgery and post op)