Blood gases, misc.

Question 1

anion gap equation

Answer 1

([Na+] + [K+]) - ([Cl-] + [HCO3-])

Question 2

What are the 4 causes of high anion gap metabolic acidosis?

Answer 2

1. lactic acidosis
2. Ketoacidosis
3. Toxins
4. Renal failure

Question 3

What are the 2 types of ketoacidosis?

Answer 3

Alcoholic and diabetic

Question 4

Name 3 toxins (other than ethylene glycol, propylene glycol, and methanol) that can cause ketoacidosis.

Answer 4

ASA, Urea, isoniazid, cyanide, iron

Question 5

What are the 2 causes of normal gap metabolic acidosis?

Answer 5

1. Diarrhea

2. Renal loss of HCO3-

Question 6

What are the main causes of renal loss of HCO3-?

Answer 6

diuretic use or RTA type I, II, or IV

Question 7

alveolar gas equation (no values)

Answer 7

pAO2 = FiO2(pATM - pH2O) - (paCO2/RQ)

Question 8

alveolar gas equation (w/ usual values at sea level/room air)

Answer 8

pAO2 = 0.21(760 - 47) - (40/0.8)

Question 9

At what PaO2 is the patient considered hypoxemic?

Answer 9

<60 mmHg

Question 10

What are the main effects of opioids on the respiratory pattern?

Answer 10

high tidal volume and low respiratory rate

Question 11

What are the main effects of muscle relaxants on the respiratory pattern?

Answer 11

low tidal volumes and high respiratory rate

Question 12

What commonly used anaesthetic drug should be avoided in pts w/ low BP (i.e. shock)?

Answer 12

propafol

Question 13

What anaesthetic agents could be used to replace propafol for pts in shock?

Answer 13

ketamine or etomidate

Question 14

What is the agent of choice for GA in a pt w/ malignant hyperthermia?

Answer 14

propofol

Question 15

What special consideration is there fro injecting propofol?

Answer 15

irritating; inject lidocaine first or inject into a large vein