Respiratory pathophysiologyDepartment of Pathology Shanghai University of TCM

External RespirationGas TransportInternal Respiration

Pulmonary ventilation (total lung capacityTLC)(forced vital capacityFVC)(alveolar ventilation, VA)(residual volumeRV)(dead space volume, VD)(compliance) Gas exchange(diffusing capacity)[P(A-a)O2]

(total lung capacityTLC): 5000ml3500ml(forced vital capacity, FVC)3500ml2500ml

(residual volumeRV)1000 1500ml(functional residual capacity, FRC)2500ml

(alveolar ventilation, VA)(dead space volume, VD)(compliance)

(diffusing capacity)1mmHg [P(A-a)O2]

(respiratory failure)PaO60mmHg/PaCO250mmHg(respiratory insufficiency)

I II

(restrictive hypoventilation)obstructive hypoventilation)

1.

1. alveolar surfactant

LaplaceP=2T/r

Neonatal respiratory distress syndrome (NRDS): lack of surfactantretraction of soft tissue on inspiration

2. obstructive hypoventilation)airway resistanceR 1/r4

2. :22mm COPD

extrathoracic obstruction Inspiratory dyspnea intrathoracic obstrucdtion Expiratory dyspnia

ExpiratoryInspiratory

ExpiratoryInspiratory

isobaric point, IP

* PaO250 mmHg PAO2PACO2 PaO2PaCO2PaCO2CO2/PaCO2 PaCO2 PACO20.86Vco2/VA

diffusion impairment ventilation-perfusion imbalanceincrease of anatomical shunt

diffusion impairment

80m23540m2

PO2KPa13.310.78.005.332.67 00 0.25 0.50 0.75Hb1 212S

* IPaO2 PaCO2 O2CO2O2CO2

O2CO2

*CO2O2PaCO2

(Ventilation/perfusion ratio, VA/Q) = 4.2 / 5 = 0.840.6~3.0

ventilation-perfusion imbalanceVA/Q : Venous Admixture VA/Q : Alveolar Dead Space

1. VA/Q VA/Q(venous admixtrue)(functional shunt)

1. VA/Q 3% 30%-50% (-)

2. VA/Q VA/Q(dead space like ventilation)30% 60%-70%

VA/QIPaO2 PaCO2 O2CO2O2CO2

VAVA / QPaO2 CaO2PaCO2CO2 CaCO2 NN NN

QVA / QPaO2 CaO2PaCO2CO2 CaCO2 NN NN

3. (anatomic shunt)-2~3%ture venous admixture

1. CO2K+

1.

2. PaO2 < 60mmHg PaO2 < 30mmHg PaCO2 > 50mmHg PaCO2 > 80mmHg PaO2

2. II(30%)(12L/min)PaO2 5060mmHg

3.

3. A

3. A

4. PaO260mmHg PaO240~50mmHg PaO220mmHg PaCO280mmHg CO2

(pulmonary encephalopathy) ATP Na+-K+ -

5. GFR

PaO2PaCO2

(acute respiratory distress syndromeARDS)(acute lung injuryALI)

() (40%)

ALI-TNFIL-1[5-5-HTA2TXA2LTSFDP]

ALI

Chronic obstructive pulmonary diseaseCOPD2mm

COPD:

(respiratory failure)PaO60mmHg/PaCO250mmHgPaO2PaO2PaO2=1000.325mmHgPaCO2400.5mmHg (respiratory insufficiency)(respiratory failure) 1. PaOPaCO2PaCO2I IIPaOPaOPaCO22. PaO2PaCO2PaO2PaCO2 3. 4. ARDS26.0L/min4.2L/min30%

/chronic obstructive pulmonary diseaseCOPD COPD2mm-LaplacePTrP=2T/ralveolar surfactant3 -LaplacePTrP=2T/ralveolar surfactant

2 2mm 2()isobaric point, IPisobaric point, IP

3 PaO250 mmHgPAO2PACO2PaO2PaCO2PACO2VAVco2, PACO20.86Vco2/VAVco2PACO2PACO2PaCO2

180m23540m22 1m

30.750.34O20.25CO20.130.75IPaO2 PaCO2 IO2CO2100mlHb8ml CO2100mlHbO235ml O2CO2 CO2O224CO2O221CO2O2CO2O2PaCO2 O2CO2100mlHb8ml CO2100mlHbO235ml

O2CO2 CO2O224CO2O221CO2O2CO2O2PaCO2

VA4.2L/minQ5L/minVA/Q0.84VA/Q3.00.6VA/Q0.8 ventilation-perfusion imbalance 3%30%~50%VA/Q(dead space like ventilation)30%60%~70% IPaO2PaCO2 VA / QCO2CO2CO2CO2 CO2CO2CO2CO2

CO2CO2CO2(anatomic shunt)-2~3%ture venous admixture-PaO2PaCO2PaO2PaO2 1 NH3 1 NH3 2 3 4 PaO2AA PaO260mmHgPaO230mmHg PaCO2PaCO2 80mmHg PaO2 PaCO2CO2 AcapA PaO2