Abnormal gas exchange

Question 1

causes of hypoxemia

Answer 1

V/q mismatch, shunt, diffusion abnormality, hypoventilation, low FiO2

Question 2

v/q

Answer 2

most common. low PaO2 (severe less than 60)

Question 3

shunt

Answer 3

wide gradient, no change on Pa02 with support

Question 4

diffusion abnormailty

Answer 4

usually only present WITH EXERCISE.

Question 5

hypoventilation

Answer 5

narcotics!! high paCo2, may improve with increased Fio2

Question 6

low Fio2

Answer 6

fire/alt

Question 7

which hypoxemia causes have wide gradient

Answer 7

v/q, shunt, diffusion

Question 8

which hypoxemia causes have no gradient

Answer 8

hypovent and low FiO2

Question 9

PiO =

Answer 9

FiO2(PB-PH20)

Question 10

PA02=

Answer 10

FiO2(PB-PH20)-

Question 11

PAO2-PaO2

Answer 11

FiO2(Pb-Ph2o)- (Pao2+PaCo2/r)

Question 12

CaO2=

Answer 12

1.34(Hgb)(Sao2)+.003(PaO2)

Question 13

normal carried oxygen

Answer 13

21.2

Question 14

normal gradient

Answer 14

0-10

Question 15

what is the biggest determinant of carried oxygen

Answer 15

hemoglobin

Question 16

hyperventilation effects

Answer 16

mostly more PaCo2, not a huge effect on oxygen

Question 17

response to V/q mismatch

Answer 17

hypoxic vasoconstriction

Question 18

PaCo2 normal value

Answer 18

normal 35-45

Question 19

hypercapnia def

Answer 19

PaCo2>45

Question 20

causes of hypercapnia

Answer 20

fever, thyroid, catabolic state, overfeeding, but also ventilation or dead space problem!!

Question 21

effect of increased minute vent on PaCo2

Answer 21

decrease