Surgery Pretest

Question 1

Complication of jejunoileal bypass surgery that may cause nephrolithiasis?

Answer 1

Hyperoxaluria

Question 2

GI conditions that cause hypomagnesemia?

Answer 2

malnourishment, large GI fluid loses (Crohns, UC, diarrhea)

Question 3

EKG differences between hypocalcemia and hypomagnesemia?

Answer 3

Hypocalcemia: Long QT, T-wave inversion, heart blocks

Hypomagnesemia: Long QT and PR, ST depression, flattening or inversion of P waves, tornado de pointe

Question 4

Neuromuscular effects of hypomagnesemia?

Answer 4

Resembles hypocalcemia: paresthesias, hyperreflexia, muscle spasm, ultimately tetany.

Question 5

Antibiotic therapy for elective colon resections: # of doses, route, spectrum, need for additional doses?

Answer 5

: only one dose, less than one hour before surgery

Route: IV and non-absorbable oral (colon only)
Spectrum: Aerobes and anaerobes (again, colon spec)
Additional: Based on drug half-life if case is long and complex. No Abx for more than 24 hours.

Question 6

In a patient with hx of MI more than 6 months ago, what is the appropriate testing for elective surgical clearance?

Answer 6

Cardio stress test followed by echocardiogram.

Exercise stress test is appropriate if patient is able, otherwise persantine thallium pharmacologic test is done.

Question 7

Sign of uncompensated metabolic alkalosis?

Answer 7

normal PCO2. Respiratory compensation raises PCO2, and metabolic processes affect HCO3, not PCO2.

Question 8

Patient with NG tube, hypochloremic, hypokalemic metabolic alkalosis. Tx? Pathophys?

Answer 8

Tx: Normal saline infusion, +/- KCl infusion.
Pathphys: Volume depletion leads to Na and water retention, reducing kidney’s output and ability to excrete HCO3. Volume replenishment reverses this.

Question 9

Indications for placement of vena cava filter

Answer 9

1 - contraindication to heparin
2 - Failure of anticoagulation therapy (i.e. PE with adequate anticoagulation, etc.)
3 - known, free floating venous clot,
4 - previous history of PE
In other words, try anticoagulation first and place filter later if needed

Question 10

Effect of transfusion reaction? Sx of intraoperative and postoperative transfusion reaction?

Answer 10

Diffuse loss of clot integrity. Hot compliment mediated hemolysis causes hypotension, activates coagulation and DIC. fever, chills, pain, redness on infused vein, respiratory distress, anxiety, oliguria
Intra: Sudden appearance of diffuse bleeding
Post-op: unexplained fever, apprehension, headache

Question 11

HIT: Complications, immediate treatment, long term tx?

Answer 11

Complications: venous and/or arterial thromboembolic events.
Immed Tx: DC all heparins, use non-heparin anticoag like lepirudin or agatroban (direct thrombin inhibitors)
Long term tx: transition to warfarin only after plt > 100,000

Question 12

Stages of SIRS and sepsis and their definitions?

Answer 12

SIRS: T 38+/36- HR 90+ R 20+/PCO2 32- WBC 12+ 4-
Sepsis: SIRS + documented infection
Severe Sepsis: Sepsis + organ dysfunction OR hypo perfusion (lactic acidosis, oliguria, AMS)
Septic shock: Sepsis + organ dysfunction AND hypo perfusion (SBP 90- or 90+ with pressors)

Question 13

Timing of feeding post intestinal surgery?

Answer 13

Early enteral nutrition is recommended. Stomach is uncoordinated for ~24 hrs after surgery, but small intestine accepts nutrients promptly (less than 24hrs) via nasoduodenal or jejunal catheter.

Question 14

Def high output fistula?

Answer 14

500+ mL/day

Question 15

Factors that predispose to fistulae formation or prevent closure?

Answer 15

FRIENDS:

Foreign body, Radiation, Inflammation, Epithelialization of the tract, Neoplasm, Distal obstruction, Steroids

Question 16

Signs of adrenal insufficiency?

Answer 16

AMS, fever, CV collapse, hypoglycemia, hyperkalemia.

Like sepsis, but with glycemic and K+ changes

Question 17

Pre-op care for patients with hemophilia A?

Answer 17

A is for Eight! VIII deficiency
Mild hemophilia: DDAVP
Severe hemo: DDAVP and E-aminocaproic acid (anti fibrinolytic)

Question 18

Replacement fluids for fluid loss in various parts of the GI tract?

Answer 18

Duodenum, jejunum, ileum and bile = Ringer Lactate
Saliva, gastric juice, right colon = High K+, low Na+
Pancreatic secretions = High bicarb

Question 19

Kayexalate MOA?

Answer 19

Cation exchange resin that exchanges sodium for K+ in the gut.

Question 20

symptoms of zinc deficiency?

Answer 20

Alopecia, poor wound healing, night blindness or photophobia, anosmia, neuritis, skin rashes. Often develops with diarrhea.

Question 21

Symptoms of selenium deficiency?

Answer 21

Development of cardiomyopathy

Question 22

Symptoms of molybdenum deficiency?

Answer 22

Encephalopathy due to accumulation of sulfur containing amino acids

Question 23

Symptoms of chromium deficiency?

Answer 23

Difficult to control hyperglycemia, peripheral neuropathy, encephalopathy

Question 24

Thiamine deficiency?

Answer 24

Beri-beri - encephalopathy and peripheral neuropathy. Cardiac symptoms and heart failure may occur as well.

Question 25

Uses of LR vs NS vs 1/2NS vs Colloids for acute volume resuscitation in trauma?

Answer 25

LR: Isotonic fluid used in 3:1 ratio for replacing blood loss, OK to use high volumes if needed
NS: Isotonic fluid used 3:1 ratio for replacing blood loss, but large volumes may cause non-anion gap acidosis due to inc [Cl-]
1/2NS: Hypotonic fluid should not be used in acute resuscitation, but good for maintenance fluids
Colloids: Controversial in acute fluid resuscitation, but OK to administer in a 1:1 ratio

Question 26

Definitive treatment for hypovolemic shock?

Answer 26

Volume replenishment i.e. fluid resuscitation

Vasopressors are not definitive treatment

Question 27

Treatment for rhabdomyolysis?

Answer 27

Urine alkalinization
Loop diuretics
Manitol

Question 28

Appropriate fluids for pt with NG tube?

Answer 28

Regular maintenance fluids - D5 1/2NS (4mL, 2mL, 1mL/hr)
+/- potassium chloride (dep on renal function)
+ LR or NS equivalent to NG output to replace GI losses

Question 29

What is the definitive treatment for hyperkalemia?

Answer 29

Removal of K+ ions for the body. Kayexalate accomplishes this, but slowly. A patient may also receive dialysis if it is urgent, esp in the setting of renal failure.

The following are all temporary measures:
Calcium gluconate rapidly resolves cardiac complications. Na-bicarb alkalinizes the blood (think H+/K+ “pumps”). Glucose + insulin also shift K+ into cells.

Question 30

Dx and Tx of hemolytic transfusion reaction?

Answer 30

Dx: Oliguria + hemoglobinuria: Increased hemoglobin in plasma is cleared by kidneys, causing hemoglobinuria, measured in urine (oliguria also occurs 2/2 hypotension).

Tx: Fluids and mannitol: Aggressive fluid resuscitation and osmotic diuresis.

Question 31

Treatment of pseudomembranous colitis: first line, second line, indications for surgery?

Answer 31

1st: oral metronidazole
2nd: oral vancomycin
Surgical indications: intractable disease, failure of medical therapy, toxic megacolon, colonic perforation.

Dx: Toxin A or B in stool or characteristic appearance on endoscopy

Question 32

How are daily caloric requirements affected in starvation? Routine surgery? Burns over 50% of body? Multiple organ failure?

Answer 32

BMR requirements are affected by different physiologic states, reflected in the “stress factor”. Caloric needs are determined by the patients BMR x stress factor.
Starvation: 0.9 or 90% of normal BMR/calories
Routine surgery: 1.1
Burns over 50%: 2.0 (twice the normal daily calorie req’d)
MOF: 1.5

Question 33

What is the mechanism by which PEEP increases oxygenation?

Answer 33

PEEP increases functional residual capacity by keeping the alveoli open at the end of expiration

Question 34

Consequences of cardiac tamponade: Pulsus paradoxes, Echocardiogram, swan-ganz reading?

Answer 34

Pulsus: Decrease of more than 10mmHg at end of inspiratory phase
Echo: pericardial fluid and right atrial collapse
Swan-Ganz: equalization of pressures across four chambers
Right atrial and CVP are increased, CO is decreased

Question 35

Major predictors of cardiac events during surgery?

Answer 35

Unstable angina, recent myocardial infarction, decompensated congestive heart failure, significant arrhythmias, severe valvular disease

Question 36

Where should epinephrine-containing lidocaine solutions not be used?

Answer 36

In tissues supplied by end arteries, such as fingers, toes, ears, nose, or penis.

Question 37

Treatment of malignant hyperthermia? Tx for urine? Agents to avoid? Tx for future surgery?

Answer 37

Immediate cessation of anesthetics
Hyperventilation with 100% O2 (MH increases O2 demand and CO2 production)
Administration of dantrolene sodium

Urine: alkalization to prevent myoglobin precipitation

Avoid: succinylcholine

Future: pretreat with dantrolene for 24 hours

Question 38

Treatment for known aspiration?

Answer 38

Bronchoscopy

Question 39

Diagnosis for ventilator associated pneumonia?

Answer 39

Bronchoalveolar lavage: Greater than or equal to 10,000 colony-forming units/mL of a single organism is diagnostic

Question 40

Preferred vasopressors for septic shock?

Answer 40

Norepinephrine and dopamine

Epinephrine only vasoconstricts peripherally, and also increases cardiac contractility, not first line in septic shock

Question 41

Side effect of succinylcholine? Morphine?

Answer 41

Succ: Increased serum potassium
Morphine: Hypotension