Surgery: Injury, Fluids and Metabolism

Question 1

Definition of normal anion gap and it’s formula.

Answer 1

Anion Gap= Na - (Cl+ HCO3)

Normal anion gap is lesser than or equal to 12mmol/ L

Question 2

At what stage of dehydration is hypotension seen?

Answer 2

Hypotension and thready pulse is seen in severe dehydration (11-15% body weight lost as water).

Moderate dehydration means 6-10% lost as water)
Severe thirst
Nausea
Dry axilla and groin
Tachycardia
Orthostatic hypotension
Low CVP
Poor skin turgor
Apathy
Oliguria
Hemoconcentration

Question 3

Which of the following would most likely cause normal anion gap metabolic acidosis?

a. Renal insufficiency
b. Diabetic ketoacidosis
c. Lactic acidosis
d. Ureterosigmoidoscopy

Answer 3

d. Ureterosigmoidoscopy

NAGMA is to HARDUP (Hyperalimentation-Acetazolamide-Renal tubular acidosis-Diarrhea-Ureteroenteric fistula-Pancreaticoduodenal fistula)

Causes
HCL administration
Bicarbonate loss
GI losses 
Renal tubular acidosis
Carbonic anhydrase inhibitor

Question 4

Which of the following is not a cause of high anion gap metabolic acidosis?

a. Exogenous acid production through renal insufficiency.
b. GI losses in cases of diarrhea
c. Exogenous acid ingestion
d. None of the above

Answer 4

HAGMA = MUDPILES

Causes

1. Exogenous acid ingestion (Methanol, ethylene glycol and methanol)
2. Endogenous acid production (Ketoacidosis, lactic acidosis, and renal insufficiency)

M U D P I L E S

Methanol
Uremia (Renal Failure)
Diabetic ketoacidosis
Propylene glycol and paraldehyde
Infection, iron and isoniazid
Lactic acidosis
Ethylene glycol
Salicylates

Question 5

Triad of milk alkali syndrome

Answer 5

The milk-alkali syndrome consists of the triad of 1. HYPERCALCEMIA ,2. METABOLIC ALKALOSIS and 3. RENAL INSUFFICIENCY associated with the ingestion of calcium and absorbable alkali.

Hypercalcemia causes a vasoconstriction-induced decline in glomerular filtration rate (GFR) and activation of the calcium-sensing receptor in the medullary thick ascending limb, resulting in natriuresis and volume depletion. The combined effects of increased alkali intake, decreased GFR, and volume depletion lead to metabolic alkalosis.

Question 6

Symptoms of hypernatremia are rare until serum sodium concentration exceeds ______.

Answer 6

In hypernatremia, symptoms occur at 160mEq/L serum sodium concentration.

In hyponatremia, symptoms do not occur until serum sodium level is 120mEq/L.

Question 7

What are the four families of adhesion molecules?

Answer 7

Selectins
Immunoglobulins
Beta (CD18) integrins
Beta (CD29) integrins

Question 8

Choosing an ECF expander among the electrolyte solutions for parenteral administration would require preparation near 280mOsm. Which of the following would the IV of choice?

a. LR or PNSS
b. PNSS or D5LR
c. D5NS or D5LR
d. D5 0.25% NaCl

Answer 8

answer is a. LR (280mOsm) or PNSS (308mOsm)

Question 9

What is the most common cause of extracellular deficit among surgical patients?

Answer 9

Loss of GI fluid from nasogastric suction, vomiting, diarrhea or enterocutaneous fistula.

Question 10

Correction of asymptomatic hyponatreamia should increase by no more than what rate?

Answer 10

Answer. No more than 0.5 mEq/l/hr to a maximum of 12 mEq/l/d

For hypernatremia and symptomatic hyponatremia correction, it should he no more than 1mEq/l/h

Question 11

True or false.

A 100lbs patient with unintentional weight loss of 9lbs within 6months is considered significant.

Answer 11

False.

1 week: 2%
1 month: 5%
3 months: 7.5 %
6 months: 10%

More than that, it’s called severe weight loss

Question 12

Compute for the ideal body weight of a 5 feet and 1inch tall woman using the Modified Broc’s formula.

Answer 12

105 lbs or 47.3kgs

Question 13

What is the basal caloric requirement of a normal healthy adult?

Answer 13

25-30kcal/kg/day

Question 14

The following are seen in the Ebb phase of surgical metabolism;

a. Increased BMR
b. Decreased BMR
c. Mobilization of energy stores
d. Positive nitrogen balance.

Answer 14

answer. b decreased BMR (since the body tries to repair and conserve energy reserves)

There are two phases the Ebb and Flow (catabolic and anabolic) in surgical metabolism
1-2 days post injury: EBB PHASE: Conservation
1-2 weeks post operative-CATABOLIC: Mobilization
Months: ANABOLIC: Replacement or recovery

Question 15

Surgical patients who are in a lot of stress like burn patients need how many grams of CHON per kg/day?

a. 1.2
b. 1.5
c. 2
d. 2.5

Answer 15

Answer is d. 2.5

Note the correction factor (protein) was asked not the calorie factor correction/ adjusment above BEE.

If CHON,

1. 2 mild stress
2. 5 moderate stress
3. 0 severe sepsis
4. 5 burns

Question 16

Which of the following could be a possible complication of prolonged parenteral nutrition?

a. Microcytic anemia
b. Scaly dermatitis and loss of hair
c. Glucose intolerance
d. Diffuse eczematoid rash at intertriginous areas.
e. Intestinal mucosal granulation

Answer 16

Answer is E

A. Copper deficiency
B. Essential fatty acid deficiency
C. Chromium deficiency
D. Zinc deficiency

Question 17

Management in potentially fatal shifts in fluids and electrolytes that may occur in malnourished patients receiving artificial refeeding.

Answer 17

Management if Refeeding Sydrome: SLOW initiation in the first week (50% of requirements based on dry weight)

Question 18

High doses of protein intake may lead to the following except;

a. Hypertonic dehydration
b. Azotemia
c. Dehydration
d. Acidosis (metabolic)
e. Hyperglycemia

Answer 18

D. Hyperglycemia

This is seen in overfeeding with glucose infusion also hypertriglyceridemia and hepatic steatosis.

Question 19

Four stages of hemostasis

Answer 19

Vascular constriction
Platelet plug formation
Fibrin formation
Fibrinolysis

Question 20

Earliest ECG finding in cases of hyperkalemia (above 3.5-5 mEq/L).

Answer 20

Answer. High peaked T waves

followed by widened QRS, P wave flattening, PR interval prolongation, sine wave formation and Vfib

Question 21

This binds to potassium in exchange of sodium, hence used in cases of hyperkalemia. What is this cation-exchange resin?

Answer 21

Kayexalate

Question 22

When ECG changes are present such as peaked t waves and p wave flattening in the setting of hyperkalemia, this solution can be administered.

Answer 22

Calcium Gluconate (5-10mL of 10% solution)

Question 23

The following are manifestations of hypokalemia except;

a. Ileus
b. Constipation
d. Vomiting and diarrhea
e. Cardiac arrested

Answer 23

Vomiting and diarrhea is a manifestation of hyperkalemia

Question 24

At what concentration is hypercalcemia symptomatic?

Answer 24

When it exceeds 12mEq/L

Treatment: Volume repletion and brisk diuresis with normal saline

Question 25

What is the critical level for serum calcium?

Answer 25

15mEq/L

Question 26

Neuromuscular symptoms in cases of hypocalcemia do not occur until ionized fraction falls below _____.

Answer 26

2.5mg/dL

Treatment for hypocalcemia
IV 10% calcium gluconate
Correction of deficits in Mg, K, and pH
Check serum albumin to compute corrected calcium

Each 1g/dL decrease in serum albumin concentration will lower the total calcium concentration by approximatelt 0.8mg/dL.

Question 27

True or false.

Hypomagnesemia can produce hypocalcemia and lead to persistent hypokalemia.

Answer 27

True

Hypomagnesemia looks like hypocalcemia while hypermagnesemia looks like hyperkalemia.

Question 28

The following are seen in refeeding syndrome except;

a. Hypokalemia
b. Hypomagnesemia
c. Thiamine deficiency
d. Oedema
e. None of the above

Answer 28

None of the above

Question 29

Which of the following abnormalities would  cause decreased DTRs?
A. Hypokalemia
B. Hypomagnesemia
C. Hypocalcemia
D. Hypoglycemia

Answer 29

Hyperkalemia causes decreased DTRs

Hypomagnesemia and hypocalcemia cause hyperactive reflexes and even seizures.