Exam 2 Oxygen Indices & ICU Assessment

Question 1

what does P50 indicate

Answer 1

hemoglobin is 50% saturated with oxygen

normal P50 is 27 mmHg

Question 2

how is P50 affected when curve shifts left

Answer 2

increase Hb affinity for O2
increase pH
decrease CO2
decrease temperature
decrease 23DPG
P50 decrease

Question 3

how is P50 affected when curve shifts right

Answer 3

decrease Hb affinity for O2
decrease pH
increase CO2
increase temperature
increase 23DPG
P50 increase

Question 4

what is the significance of utilization of monitoring systems in ICU

Answer 4

continuous assessment

measures values caregivers cant detect

Question 5

what is the significance of P/F ratio

Answer 5

determine if dealing with ALI or ARDS

identify acute hypoxemic failure

Question 6

what is the significance of

P(A-a)O2 difference

Answer 6

indicates gas exchange efficiency

help narrow the cause of hypoxemia

Question 7

what is the significance of PaO2/PAO2 ratio

Answer 7

useful for gas exchange index with changing FiO2

Question 8

what is the significance of

C(a-v)O2

Answer 8

how much oxygen is removed from blood in capillaries as it circulates into the body

Question 9

what is the significance of O2 ER

Answer 9

assess the adequacy of systemic oxygen delivery

Question 10

what can affect SpO2 readings

Answer 10

motion artifact
environmental light
anemia
deeply pigmented skin
carboxyhemoglobin
methemoglobin
nail polish
blood-borne dyes (cyanide)

Question 11

define anemia

Answer 11

lack of healthy RBC to carry oxygen to tissues

Question 12

when is cyanosis noted on a patient

Answer 12

5g/dL desaturation of hemoglobin

Question 13

what is the importance of assessing a patients baseline prior to diagnostic procedures

Answer 13

to compare and see how the patient is tolerating the procedure

Question 14

how is a shunt determined using P(A-a)O2 and P/F ratio

Answer 14

for every 50 mmHg difference in A-a gradient, a 2% shunt is approximated

Question 15

how is a ALI determined using P(A-a)O2 and P/F ratio

Answer 15

if the P/F ratio is < 300 its ALI, < 200 its ARDS

Question 16

how is a V/Q mismatch determined using P(A-a)O2 and P/F ratio

Answer 16

an elevated A-a gradient indicated V/Q mismatch

Question 17

how is a ARDS determined using P(A-a)O2 and P/F ratio

Answer 17

if the P/F ratio is < 200 its ARDS

Question 18

what is Qs/Qt indication of

Answer 18

effectiveness of pulmonary oxygenation

Question 19

what increased the Qs/Qt value

Answer 19

atelectasis
pneumonia
ARDS
pulmonary edema
pulmonary vasodilation
inotropic agents

Question 20

when does the body’s compensatory mechanism or increased C.O. get triggered

Answer 20

your body will shunt blood to vital organs if C.O. drops

Question 21

what increases C(a-v)O2

2 things

Answer 21

low C.O.

increased VO2

Question 22

what increases SvO2

3 things

Answer 22

decrease O2 ER
decrease VO2
decrease C(a-v)O2

Question 23

what increases PvO2

4 things

Answer 23

increase C.O.
increase Hb
increase SaO2
decrease VO2

Question 24

what increases VO2

5 things

Answer 24

exercise
trauma
inflammation
sepsis
shivering

Question 25

what increases DO2 | *1 thing*

Answer 25

septic shock

Question 26

what increases O2ER | *3 things*

Answer 26

low C.O. increased VO2 decreased CaO2

Question 27

what decreases C(a-v)O2 | *4 things*

Answer 27

septic shock increased C.O. anemia left shift on curve

Question 28

what decreases SvO2 | *5 things*

Answer 28

``` suctioning shivering extubation weaning PPV ```

Question 29

what decreases PvO2 | *4 things*

Answer 29

decrease C.O. decrease Hb decrease SaO2 increase VO2

Question 30

what decreases VO2 | *4 things*

Answer 30

skeletal muscle relaxation (drug induced) peripheral shunting (sepsid, trauma) cyanide poisoning hypothermia

Question 31

what decreases DO2 | *2 things*

Answer 31

decreased C.O. | decreased CaO2

Question 32

what decreases O2ER | *2 things*

Answer 32

high C.O. | sepsis

Question 33

what are normal/(acceptable) values of C(a-v)O2

Answer 33

4 to 6 mL/100 mL blood or vol% | 5 vol%, <7 ml/dL

Question 34

what are normal/(acceptable) values of SvO2

Answer 34

65 to 75% | minimal >60%, >65%

Question 35

what are normal/(acceptable) values of PvO2

Answer 35

38 to 42 mmHg | 40 mmHg, >32 mmHg

Question 36

what are normal/(acceptable) values of VO2

Answer 36

100 to 140 mL/min | 250 mL/min

Question 37

what are normal/(acceptable) values of DO2

Answer 37

550 to 650 mL/min | 1000 mL/min

Question 38

what are normal/(acceptable) values of O2ER

Answer 38

75% | 750 mL

Question 39

how do you calculate OI

Answer 39

FiO2 x (MAP/PaO2) x 100

Question 40

if on conventional ventilation what is the number to switch to HFV or iNO

Answer 40

> 25

Question 41

if on conventional ventilation what is the number to switch to ECMO

Answer 41

> 40

Question 42

what is a normal value of OI

Answer 42

< 25 (20)

Question 43

how do you calculate P(A-a)O2

Answer 43

PAO2 = [(Pb - PH2O) x FiO2] - (PaCO2 x 1.25) PAO2 - Pao2

Question 44

how do you calculate estimated shunt

Answer 44

(CcO2 - CaO2) / (CcO2 - CvO2) CcO2 = (Hb x 1.34) + (PaO2 x 0.003) CaO2 = (SaO2 x Hb x 1.34) + (PaO2 x 0.003) CvO2 = (SvO2 x Hb x 1.34) + (PvO2 x 0.003)

Question 45

how do you calculate CaO2

Answer 45

(Hb x 1.34 x SaO2)+(PaO2 x 0.003)

Question 46

how do you calculate C(a-v)O2

Answer 46

CaO2 = (Hb x 1.34 x SaO2) + (PaO2 x 0.003) CvO2 = (Hb x 1.34 x SvO2) + (PvO2 x 0.003)

Question 47

how do you calculate VO2

Answer 47

C.O. x (CaO2 - CvO2) x 10

Question 48

how do you calculate DO2

Answer 48

C.O. x CaO2 x 10 CaO2 = (SaO2 x Hb x 1.34) + (PaO2 x 0.003)

Question 49

how do you calculate O2ER

Answer 49

[C(a-v)O2 / CaO2] CaO2 = (SaO2 x Hb x 1.34) + (PaO2 x 0.003) CvO2 = (SvO2 x Hb x 1.34) + (PvO2 x 0.003)

Question 50

how is ICP assessed in ICU patients

Answer 50

fluid filled system with external transducer | solid state system with miniature pressure transducers

Question 51

how is nutrition assessed in ICU patients

Answer 51

obtain history perform physical exam appraisal of muscle and organ function

Question 52

how is renal function assessed in ICU patients

Answer 52

assessing BUN assessing creatinine assessing urine volume

Question 53

how is neurological status assessed in ICU patients

Answer 53

obtain history exam: mental status, pupillary response and eye movement, corneal and gag reflex, respiratory rate and pattern, ICP monitoring (10-15 normal), Glasgow coma scale

Question 54

how is hemodynamic stability assessed in ICU patients

Answer 54

ECG for arrhythmias | arterial blood pressure for integrity of cardiovascular tone