Question

Please state each statement is right or wrong and explain in detail.

1. Subject A has the following values: Minute ventilation = 7 liters/minute, Respiratory frequency = 16 Br/minute, PaCO2 = 35 mm Hg, PECO2 = 27 mm Hg. Identify whether each of the following are correct or incorrect.

a. VT = 2.3 liters

b. VD/VT = 0.23

c. the alveolar volume is 77% of the Vt

d. VA = 5.4 liters/minute

2. Subject B is a 5 foot tall 185 pound male with the following values: Minute ventilation = 8 liters/minute, Respiratory frequency = 30 Br/minute, PaCO2 = 50 mm Hg, PECO2 = 20 mm Hg. Identify whether each of the following is correct or incorrect.

a. VT = 0.27 liters

b. VT is within normal limits

c. VD/VT is 0.6

d. VD/VT is within normal limits

e. The patient is hypoventilating

f. The respiratory rate is within normal limits

g. The patient’s dead space volume 185 ml

h. The patient’s dead space volume is within normal limits

i. The PaCO2 is elevated simply due to shallow breathing

3. Subject C has the following values: Minute ventilation = 8, liters/minute, Respiratory frequency = 4 Br/minute, PaCO2 = 20 mm Hg, PECO2 = 15 mm Hg. Identify whether each of the following is correct or incorrect.

a. VD/VT is within normal limits

b. VT is within normal limits

c. the subject is hyperventilating

d. the PaCO2 is low because the patient is breathing rapidly

e. the PaCO2 is low because the alveolar ventilation is higher than normal

4. Subject D has the following values: Minute ventilation = 60 liters/minute, Respiratory frequency = 60 Br/minute, PaCO2 = 30 mm Hg, PECO2 = 24 mm Hg, VCO2 = 1668 ml/minute. Identify whether each of the following is correct or incorrect.

a. the tidal volume = 1 liter

b. the VD/VT is 0.45

c. the alveolar ventilation = 28 liters/minute

d. the subject’s metabolic rate is higher than normal

e. this subject is probably exercising

5. Subject E is a 21 year old college student who has the following values at baseline: PaO2 54 mm Hg, PaCO2 = 60 mm Hg while breathing FIO2 = 0.21 @ PB = 690 mm Hg. A Respiratory Therapist administers additional oxygen with an FIO2 = 0.4. Identify whether each of the following are correct or incorrect.

a. At baseline, the PaCO2 is within normal limits

b. At baseline, the PaO2 is within normal limits

c. At baseline, the value for PaO2 explained by hypoventilation alone

d. The a/A ratio is consistent with low V/Q or shunting

e. Administration of oxygen will result in a decrease in PaCO2 proportional to the increase in PaO2

f. Administration of 40% oxygen would be expected to result in a PAO2 = 257 mm Hg

6. Subject F has the following values: FIO2 = 0.7, PaO2 250 mm Hg, Hb 6 g/dl, SVO2 = 50%, CO = 6 lpm, PaCO2 = 35 mm Hg. Estimate the SaO2 and PVO2 using the normal oxyhemoglogin dissociation curve, and identify whether each of the following is correct or incorrect.

a. The subject has low V/Q

b. The SaO2 = 100%

c. The PVO2 = 26 mm Hg

d. The oxygen consumption is about 280 ml/minute

e. The subject must be exercising

f. Dissolved CO2 = 0.105 meQ/L

Answer 1

a) VT 2.3L is incorrect

minute ventilation is 7L/minute

respiratory rate(RR) is 16breaths/min

So,

  .

b) VD /VT 0.23 is correct

  PaCO2 is 35

PECO2 is 27

formula to calculate VD/VT is,

VD/VT

c) alveolar volume is 77% VT is correct.

so,

   , it is 77% of VT

d) VA 5.4 is correct

formula for VA( alveolar ventilation) is,

to find VD( volume of dead space),