pulm review Flashcards
What is equation for lung compliance?
C = V/P
What are the 3 forces that control respiratory system?
- chest wall expansive force
- lung elastic collapsing force
- frictional resistance determines lung compliance
equation for pulmonary vascular resistance (PVR)
PVR = (mPAP - mLAP) / CO
pulm artery P - left atria P
systolic and diastolic pulmonary artery pressure?
systolic: 25 mmHg
diastolic: 10 mmHg
Normal Patm
760 mmHg
Normal Ph2o?
47 mmHg
Normal FiO2 [fraction of inspired O2]
0.21
What is R?
respiratory quotient = 0.8
What is normal cardiac output?
6 L/min
What is normal V/Q?
0.8
What is normal PaCO2?
40 mmHg
What is normal A-a gradient?
< 10 mmHg
What is equation for minute ventilation rate [Ve]
Ve = Vt * RR Vt = tidal volume RR = respiratory rate
What are two equations for alveolar ventilation rate? [hint: one uses Vt and one uses Vco2]
V[A] = (Vt - Vd) * RR Vt = tidal volume Vd = dead space
V[A] = Vco2 * K / PACO2 Vco2 = rate of CO2 production PACO2 = alveolar PCO2 K = 863 mmHg for BTPS conditions
What is equation for physiologic dead space?
Vd = Vt * (PaCO2 - PECO2)/PaCO2
PaCO2 = alveolar or arterial PCO2 PECO2 = expired PCO2
What is normal Vd/Vt ratio?
1/3
What is normal Vd?
150 mL
What is normal Vt?
450 mL
What is normal RR?
14 / min
What is the alveolar gas equation?
PAO2 = FiO2(Patm - Ph2o) - PaCO2/R
What is AA gradient?
PAO2 - PaO2
Is V/Q ratio higher at bottom or top of lung?
higher at top of lung [less blood flow]
In dead space what are PAO2 and PACO2?
PAO2 = 150 PACO2 = 0
Normal body temp?
37 C
Fraction of O2, N2, and CO2 in atm at dry air 760 mmHg?
O2 = 21% N2 = 79% CO2 = 0%
What is solubility of O2 in blood?
0.003 mL O2/100 mL blood / mmHg
Daltons law for partial pressure of gas?
Px = (Pb - PH2O) * fraction of gas that is x
What is henry’s law for concentration of dissolved gas in solution?
Cx = Px * solubility Px = partial pressure of gas
Between O2, CO2, and CO which are diffusion and perfusion limited?
O2 and CO2 perfusion limited
CO diffusion limited
What is equation for O2 content of blood
O2 content = (1.34 * Hb conc * % saturation) + (0.003*PaO2)
What is equation for rate of diffusion?
DA delta P / delta X
diffusion coefficient * surface area * driving pressure difference / thickness of barrier
What is equation for O2 delivery?
O2 delivery = CO * O2 content of blood
What is the O2 binding capacity of Hb?
1.34 *Hb
What is the normal P50 of Hb?
25 mmHg
What is venous PO2 and PCO2?
PO2 = 40 PCO2 = 46
What 4 things decrease the affinity of Hb for O2?
shift curve right
- low pH
- high PCO2
- high temp
- high 2,3 DPG
What are 5 causes of hypoxemic hypoxia?
high altitude hypoventilation V/Q mismatch right to left shunt diffusion deffect
What will pulse ox show in CO poisoning?
normal – because Hb is still bound
In restriction:
- FEV1
- FVC
- FEV1/FVC
- RV
- TLC
- FEV1: lower
- FVC: lower
- FEV1/FVC: same or higher
- RV: lower
- TLC: lower
obesity, pulmonary fibrosis
In obstruction:
- FEV1
- FVC
- FEV1/FVC
- RV
- TLC
- FEV1: lower
- FVC: slightly lower
- FEV1/FVC: lower
- RV: higher
- TLC: higher
asthma, emphysema, chronic bronchitis, COPD