Physiology

Question 1

VT

Answer 1

Tidal volume (500ml)

Question 2

IRV/ERV

Answer 2

3L/1.2L

Question 3

RV

Answer 3

1.2 (FRC-ERV)

Question 4

IC

Answer 4

Insp capacity = VT+IRV

Question 5

FRC

Answer 5

Functional residual capacity = RV+ERV

Question 6

VC

Answer 6

Vital capacity=ERV->IRV

Question 7

TLC

Answer 7

Total lung capacity=IRV->RV

Question 8

Calculating FRC

Answer 8

= Vspirometer([He]start - [He]end)/[He]end

Question 9

Anatomical deadspace - FOWLER

Answer 9

In conducting airways

Nitrogen conc vs expired volume graph (initial air is dead space and has no N2—> perpendicular = Vd (2.2ml/kg)

Question 10

Physiological deadspace - BOHR

Answer 10

All air not involved in gas exchange eg.PE

Measure CO2 in tidal volume
Vd/Vt=FACO2-FECO2/FACO2 (150ML)

Question 11

Alveolar ventilation

Answer 11

Vt-Vd x breath frequency

Question 12

calculate shunt

Answer 12

(CcO2-CaO2)/(CcO2-CvO2)

CcO2 estimated using PAO2—>calculated

Question 13

calculate PAO2/PaO2/A-a difference

Answer 13

FIO2(PB-PH2O)-PACO2/RQ

Question 14

estimated dead space

Answer 14

2.2 mls per kg body weight

Question 15

alveolar ventilation

Answer 15

(vt-vd)x resp rate

Question 16

pACO2

Answer 16

rate of CO2 production/alveolar ventilation

Question 17

ph

Answer 17

pK (6.1) +(log[HCO3-]/0.03XPaCO2)

Question 18

minute volume/pulmonary ventilation rate

Answer 18

tidal volume x resp rate

Question 19

Pgas

Answer 19

Fgas x (PB-PH2O) i.e. 47mmHg

Question 20

estimate residual volume

Answer 20

(vital capacity/0.8)-vital capacity (cannot be measured using spirometer–> He dilution)