Ch.22 Respiratory physiology: THE EFFECTS OF ANESTHESIA

1
Ch.22 Respiratory physiologyTHE EFFECTS OF
ANESTHESIA

• ???

2
Cellular Respiration

• ?? ?? ??? blood ? inspired air??? gas exchange?
  ?? ???, O2? ?? CO2? ??? ?? ?
• 1. Aerobic Metabolism
• O2? ????, energy? ???.
• carbohydrates, proteins? two-carbon fragments
  (acetyl CoA) ? ????.? CO2? ???? ?? ??? energy?
  NAD, FAD, GTP? ????.? ????? Oxidative
  phosphorylation ? ?? adenosine triphosphate(ATP)
  ? ??
• glucose  
• C6H12O6 6O2    ?  6CO2 6H2O energy
• energy ADP   P  ? 38 ATP ??
• ?? ??? ?? ATP ?  ADP P energy
• Cell? ATP ADP  10 1 ? ????.
• ATP? ???? ?? ??? ?? ????, metabolic substrate? ??
  ???? ????? ???? ?

3
Cellular Respiration

• Respiratory quotient (RQ)
• ? total CO2 production(VCO2)? oxygen
  consumption (VO2)?? ??
• RQ of carbohydrates, lipid, protein 1.0, 0.7,
  0.8
• ?? ??? ?? VCO2 200mL/min  VO2 250mL/min? NL
  RQ  0.8
• (????? protein? primary fuel source?
  ???? ???, fats? carbohydate combination??? ????.)
  
• VO2    10(weight)
• 2. Anaerobic Metabolism
• 02? ???? ?? energy? ??
• glucose? pyruvate, latic acid? ??? ??
• ??? ?? ATP??(2ATP)
• 3.Effects of Anesthesia on Cell Metabolism
• ????? VO2? VCO2? ? ? 15?? ????
• ?? ?? ??? ?? ??? ????

3/4
4
Functional respiratory anatomy

• 1. Rib Cage Muscles of Respiration
• contraction of the diaphragm
• the base of the thoracic cavity ? 1.5 -7cm ??
• chest volume ??? 75
• accessory respiration muscle? ??? ??? ??? ????.
• ?? ??? ?????? ? ?, SCM, scalene, pectoralis
  muscle ??.
• SCM rib cage?????? ??? ??.
• scalene ??? upper rib? inward movement? ????.
• pectoralis muscle chest expansion? ???.

5
Functional respiratory anatomy

• Expiration? supine position ? passive?? ??????
  upright positoin ? active?? ????
• Exhalation? abdominal muscles (rectus abdominis,
  external and internal oblique, transversus) ???
  internal intercostalis ? ???? ??? ?? ????.
• some pharyngeal muscle airway patency ??? ??
• genioglossus, levator palati, tensor palati,
  palatopharyngeus, palatoglossus  

6
Functional respiratory anatomy

• 2. Tracheobronchial Tree
• ? ??? ?? alveoli? gas? ??
• ? ??? ??? ?? trachea??
  alveolar sacs?? 23
  division? ??.
• alveolar sac? 17 alveoli? ?? ? 3???
  alveoli? 50-100m2 ???
  membrane ? ??.
• Mucosa? ??? ciliated columnar? ???? ??
  cuboidal??? ?????
  alveolar epithelium? ??.
• gas exchange flat epithelium
• ??? ?? smaller airways? patency? ??
  ??? elastic recoil?
  radial traction? ???? ??.

1.Rib musles 2.Trachea 3.Circulation 4.innervati
on
7
Functional respiratory anatomy

• Alveoli
• Alveolus ?? ??   0.05-0.33 mm
• in supine, largest alveolar apex  ,smallest
  base
• inspiration? alveolar size? ?????.
• Respiratory epithelium two cell type
• type ?pneumocyte flat ?? tight junction ? ????
  albumin ?? oncotically  active molecules ? ???
  ???? ??? ??.
• type ? pneumocyte round cell?? cytoplasmic
  inclusion(lamellar bodies)? ???? surfactant?? ???
  ????. ?? cell division ? ?? type?pneumocyte,
  alveolar macrophages, mast cells, lymphocytes,
  and APUD cell, Neutrophils? ????.

8
Functional respiratory anatomy

• ??? alveolus? wall? ???? ??
• thin side (lt 0.4? )
• gas exchange? ??,
• alveolar epithelium
• capillary endothelium
• thick side (interstitial space)
• fluid and solute exchange ??
• pulmonary interstitial space ?
• ?? elastin, collagen, ??? nerve fibers ?
  ????.
• ??? 1-2?? alveolus? structural support ? ????.

9
Functional respriatory anatomy

• 3. Pulmonary Circulation Lymphatics ?? two
  circulations? ????
• Bronchial circulation
• Lt heart?? ??
• Trachea???? pumonary bornchioles ?? support ?.
• Pulmonary circulation
• Rt heart ?? pulmonary artery? ?? bronchus? ?? ??.
• ?? ????? CO2? ???? O2? ?? four main pulmonary
  veins? ?? left heart ? ????.
• Two circulation ??? direct connection? ??
• ???? ?? ??? ?? ???? ??? ??? ??? ?.

10
Functional respiratory anatomy

• Pulmonary Capillaries
• ????? ?? ?? ??? pulmonary circulation??
  capillary network? ?? ??? ??? alveolar size ? ??
  ?? ???.
• pulmonary capillary endothelium? 5nm ?? ????? ?
  ??? ??? ?? albumin?? ? molecules ? ??? ????
• alveoli? ?? ?? ??? Macrophages? ?? bacterial
  infection? ???? foreign particles ? ?????.

11
Functional respiratory anatomy

• Pulmonary Lymphatics
• Interstitial spaces?? ????
• Lymph nodes ? tracheobronchial chain? ????
  airways? ?? ???? ????.
• ?  ? ?? ??? drainage channels? trachea? ????
• left lung?? ?? fluid? ?? thoracic duct ? ?????
• ?? right lung ?? ?? ?? right lymphatic duct ?
  ????.

12
Functional respiratory anatomy

•  4.Innervation
• Diaphragm? phrenic nerves (C3-C5 nerve roots) ?
  ??
• unilateral phrenic nere block? ? 25?? pulmonary
  function??
• accessory muscle activity
• intercostal muscle ? ?? ??? thoracic nerve roots?
  ??
• vagus nerves ? tracheobronchial tree? ????? ??
• bronchial smooth muscle ? secretory gland? ?????
  ?? ??
• vagal activity bronchoconstriction , bronchial
  secretion ??
• sympathetic activity (T1-T4) bronchodilation, se
  cretion ??
• nonadrenergic, nonchoinergic bronchodilator
  system? ???
• a- and ß- adrenergic receptors? pulmonary
  vasculature ? ?????  pulmonary vascular tone? ??
  effect ? ???

13
 Basic Mechanism of Breathing

• Reoxygenates desaturated blood eliminate CO2
• Exchange of alveolar gas ??? ??? small cyclic
  pr. gradient ? ?? ????.

14
  Basic Mechanism of Breathing

• Spontaneous Ventilation
• spontaneous breathing?? normal pressure
  variation? ????.
• Pressure alveoli ? ? gt surrounding
  (intrathoracic) pressure
• pleural pressure ? intrathoracic pressure ?? ?
  ????.  
•        P transpulmonary  Palveolar  -
  Pintrapleural
• Inspiration? chest ? ???? intrapleural pressure?
  -5cmH2O ?? -8 or 9cmH2O? ??    ? ????? alveolar
  pr.??, ??? alveolar-upper airway gradient ??
• expiration?, returns intrapleural pressure to
  -5cmH2O
• elastic recoil of lung reversal of
  alveolar-upper airway gradient ? ????.

15
 Basic Mechanism of Breathing

• Mechanical Ventilation
• Positive airway pressure? ????.
• Inspiration?, upper airway? ??? ??? ??? alveoli?
  gas flow ??
• Expiratory phase of the ventilator? positive
  pressure? ???? ???? gas? alveoli ??? ???.
• Respiratory Pattern? ?? Anesthesia ? ??
• Position? anesthetic agents ? ?? ???.
• supine position?, abdominal breathing predominate
  
• ????? ??? ???? light anesthesia? irregular
  breathing patterns? ????.
• inhalation agent rapid shallow
• nitrous-narcotic slow deep
• Induction? expiratory muscles? ?????
• Inhalation agent? RR? ?? ??? tidal volume? ????

16
Mechanics of Ventilation

• ?? ??? ????? ?????, respiratory system? ??? ??
  ????.
• Respiratory system? elastic resistance ?
  gas-liquid ???, ??? nonelastic resistance? ???.
• Elastic resistance of tissue ? gas-liquid ???
  gas flow ? ?? static condition ???? lung
  volume?  pressure ??.
• elastic resistance? ???? ?(work)? energy? ??? ??
  ?? ??? energy? ????? ???
• Nonelastic resistance to gas flow  air flow ?
  tissue deformation? ?? ?? ??? ????.
• nonelastic resistance? ????? ??? energy? ?? ????.

17
Mechanics of Ventilation

• 1.Elastic Resistance
• Lung? chest ? elastic properties? ???.
• chest? expand outward ??? ,?? lung? collapse???
  ??? ??
• recoil properties of the chest deformation? ??
  ????? ??? ??? ??
• recoil properties of the lung elastin fiber? ??
  ? ??? ?? alveoli?? ?? air-fluid ???? ??????.  
•  
• Surface Tension Forces (????)
• alveoli? ?? ?? gas-fluid ???? ??? bubbles?? ??
• surface tension forces? interface? ??? ???
  alveolar collapse? ????.
• pressure 2 surface tension
•                                radius
• alveolar??   alveolar collapse ??? pressure ?
  surface tension? ???? alveolar size? ?????. (?
  surface tension? ???, alveolar size? ??? ??)
• pulmonary surfactant ? ?? surface tension? ????
  (??? ????)  lung? collapse ??

? Surfactant? ? ???.
18
Mechanics of Ventilation

• Compliance
• elastic recoil ???? ??
• (change in volume divided by change in
  distending pressure)
• supine position chest wall compliance ??
• lung compliance is defined as
•      CL           change in lung
  volume
•                            change in
  transpulmonary pressure
•       normal 150-200mL/cm H2O
•       lung volume, pulmonary blood volume,
  extravascular lung water, inflammation and
  fibrosis?? ?? ??? ?? ??? ???.
• Chest wall compliance       change in chest
  volume
•                                     
  change in transthoracic pressure
•        normal 200mL/cm H2O
• total compliance (lung and chest wall together)
  100mL/cm H2O
•  1             1          1
• Ctotal            CW            CL

19
Mechanics of Ventilation

• 2.Lung Volumes
• ????? ???? important parameter
• lung capacities? ????? ??? ????? 2?? ? ???
  volume? ???? ????.

20
Mechanics of Ventilation

• Functional Residual Capacity
• ?? ?? ???? lung volume
• ?? lung? inward elastic recoil ? chest? outward
  elastic recoil? ?????.
• nitrogen wash-out or helium wash ,body
  plethysmography? ??
• FRC ? ????? ??
• Body habitus height? ??, obesity? ???
• sex ???? 10 ??
• posture supine or prone position? ??
• lung disease lung, chest? compliance? ???? ??,
  restrictive pulmonary disorder?? ??
• diaphragmatic tone 

21
Mechanics of Ventilation

• Closing Capacity
• small airway? cartilaginous support? ??, ?? ???
  radial traction? ?? airway? ?? ??.
• lung? basal area?? patency(???)? lung volume? ??
• closing capacity? ?? airway? ?? ??? ?? volume
• tracer gas(Xenon133)?? ??
• ?? FRC?? ??
• posture? ??? ?? ???    
• age? ?? ??
• Vital Capacity
• ?? ?? ? ??? ? ?? ???
• body habitus, respiratory muscle strength and
  chest lung compliance? ??
• normal 60-70mL/Kg

22
Mechanics of Ventilation

• 3. Nonelastic Resistances
• Airway Resistance to Gas Flow
• ???? gas flow? laminar flow? turbulent flow? ???
  ??? ??
• laminar flow ?? ?? ??? ?? ?? ?? gas flow? ?? ??
  ?? ??
•             Flow      Pressure gradient
•                                Raw(airway
  resistance)               
•             Raw     8 Length Gas viscosity
•                              p
  (Radius)4
• turbulent flow ???? ???? gas flow ? ??
•           Pressure gradient  flow2 Gas
  density
•                                      
  Radius5
• Resistance gas flow? gas density? ??,
• Radius? 5??? ???(airway
  caliber? ??)

23
Mechanics of Ventilation

• Turbulent or laminar flow ??? Reynold number?
  ????
•    Reynold number linear velocity
  diameter gas density
•                               
   gas viscosity
• laminar flow lt1000   only distal to small
  bronchioles(lt1mm)   
• turbulent flow gt1500   larger airway
• total airway resistance 0.5-2 Cm H2O/L/s
• medium sized bronchi (before 7th generation)? ??
  ?? ???
• airway resistance ??? ??
• bronchospam, secretion, mucosal edema
• volume-related flow-related airway collapse

24
Mechanics of Ventilation

• A. Volume-Related Airway Collapse
• at low lung volume (loss of radial traction)
  small airway ? resistance ??? airway resistance?
  ??? lung volume? ???
• B. Flow-Related Airway Collapse
• forced exhalation??, ???? transmural airway
  pressure? ??? airway collapse? ??? ? ?? (dynamic
  airway compression)
• two contributing factors
• generation of a positive pleural pressure
• a large pressure drop across intrathoracic airway
  
• equal pressure point dynamic compression? ????
  airway point? ??
• ????? cartilagenous support? ?? 11th generation
  of bronchioles ??
• Emphysema, asthma ??? ??

25
Mechanics of Ventilation
??? 1??? ??? volume

• C. Forced vital Capacity
• ??? ??? ? ??? ??? ???? ??? ?? ??? ?? ??? ???
  ????.
• FEV1/FVC airway obstruction? ??? ??
• ????? FEV1/FVC gt 80
• FEV1 FVC effort-dependent
• FEF25-75 effort independent, ? ??? ? ??
  obstruction measurement

??? 2575 ?? ??? volume
26
Mechanics of Ventilation

• 4.Work of Breathing (WOB)
• ??? ????? ??????, ??? ??? WOB? inspiratory
  muscle(primarily diaphragm)? ?? ??? ??.
• Ventilation ?? ??? resistance? ???? ??.
• 1. elastic recoil of the chest lung
• 2. frictional resistance to gas flow
• 3. tissue frictional resistance
• Respiratory muscle? ?? ?? ???? 23? ???? ?? ???
  ???? 10? ????, ??? 90? ?? ??
• due to elastic airflow resistance

27
Mechanics of Ventilation

• 5. Effects of Anesthesia on Pulmonary Mechanics
• Effects on Lung Volume Compliance
• Induction supine position ?? additional 15-20
  reduction in FRC (400mL in most patients) - loss
  of normal end-expiratory diaphragmatic tone
• Closing capacity ?? ??? ???? ????
• Effects on Airway Resistance
• FRC? ??? airway resistance? ???? ??? ???? ??????
  bronchodilating properties? ???? ???
• Effects on the Work of Breathing   
• ?? ? work of breathing? ??? lung chest wall
  compliance? ???? ?? ????.

28
VENTILATION/PERFUSION Relationship

• 1.Ventilation
• Minute ventilation(?? ???) respirtory rate
  tidal volume (VT)
• alveolar ventilation(VA) respiratory rate (VT
  - VD)
• Dead space ( VD) tidal volume (VT) ??? gas
  exchange? ???? ?? ??
• physiologic anatomic dead space    alveolar
  dead space
•   (nonrespiratory
  airway)  (not perfused alveolar)
• ????? 150mL (?? 2mL/kg)
• ???? tidal volume? ? 450mL ???
•      VD         PACO2  - PECO2        33
•      VT               PACO2  
•   ( PACO2 alveolar CO2,  PECO2 mixed expired
  co tension)

29
VENTILATION/PERFUSION Relationship

• Distribution of Ventilation
• Ventilation? ?? ?? ??? ???? ????? ???.
• right  lung  gt  left lung (53 47)
• lower area (dependent)  gt upper area 
  (transpulmonary pr.? ??)
• Upper lung area? alveoli? ??? ???? ??, ??? non
  compliant ?
• Lower lung area(Dependent area)? smaller alveoli?
  ? ? compliant ??? expansion? ? ?
• ?? ??? pulmonary ventilation? ??? ??
• ???? ????? ????? ???? ??. ??? ????? ???? ??
  compliance? resistance ? ? ???? ????? alveolar
  filling? ????? ????? ???.

30
VENTILATION/PERFUSION Relationship

• 2. Pulmonary Perfusion
• ?? ?? 5L/min? ?? ????, ??? 70-100mL? gas
  exchange? ???? ?? pulmonary capillary? ??.
• capillary volume? ??? ?????? total pulmonary
  blood volume? 500-1000mL  ???? ?? ? ??.
• supine position?? erect ?? 27???? pul. blood
  volume ??

31
VENTILATION/PERFUSION Relationship

• Pul. vascular tone? ?? ?? local factor?
  autonomic sys. ?? ????
• Pul. arterial alveolar hypoxia? Pul.
  vasoconstriction
• leukotrienes ??, NO ????? ???
• Intrapulmonary shunting? ?? hypoxemia? ????.
• hypercapnia acidosis vasocontstrictor effect
  (hypocapnia?? vasodilate)

32
VENTILATION/PERFUSION Relationship

• Distribution of Pulmonary Perfusion
• lower (dependent) portion  gt upper portion
• zone 1 alveolar dead space 
• ? PAgtPagt Pv ? ???? ???? pul.capill? ??? ??
• zone 2 arterial-alveolar pressure gradient? ??
• zone 3 arterial-venous pressure gradient? ??
• Ventilation/Perfusion Ratios
• alveolar ventilation (VA) 4L/min     pulmonary
  capillary perfusion 5L/min
• ? V/Q rate 0.8 (0 (no ventilation) - ???(no
  perfusion))
• no ventilation
  intrapulmonary shunt
•      0.3  lt  V/Q lt 3.0
• V/Q ratio? ??? ?? ???? O2? resaturated ???.
  CO2? ???? ???? ??

33
VENTILATION/PERFUSION Relationship

• Ventilation/Perfusion Ratios
• alveolar ventilation (VA) 4L/min    
• pulmonary capillary perfusion 5L/min
• ? V/Q ratio 0.8
• (0 (no
  ventilation) - ???(no perfusion))
•    normal   0.3  lt  V/Q lt 3.0
• V/Q ratio? ??? ???? resaturated ???. CO2?
  ?????
• ?? ?? ???? ???
  

34
VENTILATION/PERFUSION Relationship

• 3.Shunts
• Shunt ???? ?? mixed venous blood? ????? ?????
  ????? ?? ?? (right to left shunt)
• Absolute shunt anatomic shunt V/Q is zero
• Relative shunt low but finite V/Q ratio

35
VENTILATION/PERFUSION Relationship

• Venous Admixture
• pulmonary end-capillary blood? artery?? oxygen
  tension??? ???? ?? ????, pulmonary end-capillary
  blood? ????? ?? mixed venous blood? ?? ???
• venous admixture (Qs)? total cardiac output (QT)?
  ??? ??
•    QS                 CcO2  -  CaO2
•    QT                   CcO2  -  CvO2
• CcO2 ???? pulmonary end-capillary bl.? oxygen
  content
• CaO2 arterial oxygen content
• CvO2 mixed venous content
• ?? Qs/ QT?  deep bronchial vein? pulmonary vein,
  thebesian circulation, low V/Q ratio ?? ?? lung
  area?? communication? ?? ??
• ???? venous admixture? 5???? shunt ?? ?? ??
  ????.

36
VENTILATION/PERFUSION Relationship

• 4.Effects of Anesthesia on Gas Exchange
• Dead space
• Hypoventilation
• Intrapulmonary shunt? ?????.
• ?? ?? ? ??? ?? atelectasis? airway collapse? ?
  ???? ?? ?? ?? venous admixture? 5-10 ???? .

37
VENTILATION/PERFUSION Relationship

• NO? ??? inhalation agents? high dose?? hypoxic
  pulm.vasoconstriction? ???? hypoxemia? ????
  
• ? ??, O2 tension? 3040 ?? hypoxemia ? ????,
  PEEP? venous admixture? ?????.
• ??? high inspired oxygen concentration(gt50)? ???
  absolute shunt? ???? ? ??.

38
Alveolar, Arterial Venous Gas Tensions

•  gas? ??? ?? ??? gas pressure? ??? ????.
•     PIO2 PB x FiO2
• 159.6mmHg 760mmHg x 0.21
• PB barometric pr. 
• FiO2 inspirarted oxygen? ??
• ?? x 7? mmHg? ??? ? ??
• kilopascal? ??? ?? ??

39
Alveolar, Arterial Venous Gas Tensions

• I. Oxygen
• Alveolar Oxygen Tension (PAO2)
• ?? ? ??? gas? humidification ?? ??? ??? inspired
  tension? ????? ??
•            PIO2 (PB -PH2O) FiO2
• alveoli?? ??? gas? ?? ???? alveolar gas(O2, CO2)?
  ????. ???
•            PAO2 PIO2 -PaCO2/RQ
• PaCO2 arterial CO2 tension, RQ respiratory
  quotient
• Inspired oxygen concentration() x 6 PAO2 mmHg

40
Alveolar, Arterial Venous Gas Tensions

• Pulmonary End-Capillary Oxygen Tension (PcO2)
• ????? PcO2 PAO2
• PcO2 (pul.end-capil.O2 tension)
  alveolar-capillary membrane ??? oxygen diffusion
  rate? pulmonary capillary blood volume transit
  time? ?? ??
•      capillary transit time pulmonary capillary
  blood volume
•                                      
  cardiac output
•                                70mL / 
  5000mL/min   (0.8sec)
• alveolar gas??? blood? ?? ????? ?? rate-limiting
  factor
• ? O2? Hb ??? ??

41
Alveolar, Arterial Venous Gas Tensions

• pulmonary diffusing capacity
• alveolar-capillary membrane?
  permeability
• pulmonary blood flow? ?? 
•                
• alveolar-capillary membrane?? ?? ??? oxygen
  diffusing capacity(DLO2)? ??
•           DLO2      oxygen uptake
•                         PAO2 PcO2
• PcO2? ??? ??? ? ?? DLCO? ?? ??
•           DLCO       carbon monoxide uptake
•                              PACO  -PcCO
• DLCO? ??? alveolar capillary memb.? ?? gas
  transfer? ??? ??
• due to abnormal V/Q ratio, destruction of
  alveolar-capillary membrane, short capillary
  transit time

42
Alveolar, Arterial Venous Gas Tensions

• Arterial Oxygen Tension (PaO2)
• alveolar-arterial oxygen partial gradient(A-a
  gradient)? 15mmHg????
• ??? ?? ?? 20-30mmHg? ??   
• PaO2      102 -age/3  
• noraml range 60-110mmHg(8-13kPa)
• ??? FRC? ?? ???? closing capacity? ??? ??? ??   

43
Alveolar, Arterial Venous Gas Tensions

• Arterial Oxygen Tension (PaO2)
•   
• hypoxemia? ?? ?? ??? alveolar-arterial
  gradient??? ??
• A-a gradient ? right to left shunt, V/Q scatter?
  ??, mixed venous oxygen tension?? ?? ??
• A-a gradient? shunt? ?? ???? mixed venous
  tension? ???
• oxygen ??? hemoglobin ??? ?? PaO2? ??? ???
  (high oxygen consumption low hemoglobin
  concentration? A-a gradient? ????, PaO2? ????)

44
Alveolar, Arterial Venous Gas Tensions

• Mixed Venous Oxygen Tension (PvO2)
• SVC, IVC, heart? ???? vein ?? ???? ?? ??
• normal 40mmHg
• ?? oxygen consumption oxygen delivery? ???
  ??? ????.
• pul. artery catheter? ?? ? ? ??.

45
Alveolar, Arterial Venous Gas Tensions

• 2.Carbon Dioxide
• Mitochondria?? aerobic metabolism? ? ???
• Mixed Venous Carbon Dioxide Tension (PvCO2)
• normal 46mmHg
• ??? ???? ?? ??????? blood? ??? ??
• Alveolar Carbon Dioxide Tension (PACO2)
• Total CO2 ??? alveolar ventilation(CO2 ??)??
  balance? ????.
•                PACO2     VCO2
•                               VA
• PACO2 ? CO2 ???? CO2 ??? ? ???
• ???? ???? ??, CO2 ???? ?? ?? ???? ??, ?? ?? CO2 ?
  ?? ? ????? ? ? ?? ??? ?? ??? PACO2? alveolar
  ventilation? ? ???? ??

46
Alveolar, Arterial Venous Gas Tensions

• Pulmonary End-Capillary Carbon Dioxide Tension
  (PcCO2)
• PcCO2 PACO2
• alveolar-capillary membrane? ?? CO2 diffusion
  rate? ??? 2???
• Arterial Carbon Dioxide Tension (PaCO2)
• normal PaCO2? 38 /- 4mmmHg ( 5.1 0.5KPa)
• ???? arterial to alveolar gradient? ??? V/Q
  abnormality ??? ??? 
• End-Tidal Carbon Dioxide Tension(PETCO2)
• end-tidal CO2 tension? ????? PaCO2? ?? ?? ??
• PACO2-PETCO2 gradient? 5mmHg ??

47
Transport of Resp. Gases in Blood

• 1.Oxygen
• 2 form?? ?? solution? ?? ???, hemoglobin? ?????
  association?
• Dissolved Oxygen
• ?? ???? ?? ???? ??? Herney's law? ?? ?? ? ??. 
•          Gas concentration    a partial
  pressure
•                a ??? ??? ??? ????? gas ?? ??
• ?? ????? ?? 0.003mL/dL/mmHg
• Hemoglobin
• 4?? heme? 4?? protein subunit?? ??? complex large
  molecule
• Heme oxygen-binding site? essential part? iron
  porphyrin compound
• ?? hemoglobin molecule (hemoglobin A1)
• 2?? a- 2?? ß-chain?? ??
• 4?? subunit? amino acid residue?? weak bond? ??
• hemoglobin 1g? 1.39mL? ??? ?? ? ??.

48
Transport of Resp. Gases in Blood

• Hemoglobin Dissociation Curve
• ? hemoglobin ? 4?? ????? ???
• hemoglobin saturation? Hb? ??? ??? ? ?? O2 ? ??
  ??? Hb? ??? O2? ?? percent? ??
• ?? 3?? ?? ??? ??? 4?? ?? ??? ????
• Saturation? 90 ??? ??? ?? ??? oxygen receptor?
  ???? curve? flatten ?? ??.

49
Transport of Resp. Gases in Blood

• Factors influencing the Hemoglobin Dissociation
  Curve
• Hydrogen ion concentration
• CO2 tension
• Temperature
• 2,3-diphosphoglyceride (2,3-DPG)concentration
• P50 hemoglobin? 50? ???? oxygen tension
• shift to right (increasing P50)
• make more oxygen available to tissue
• shift to left (decreasing P50)
• oxygen affinity ??, reducing availablity to
  tissue
• normal P50 26.6mmHg(3.4kPa)

Alkalosis Hypothermia 2,3-DPG??
Acidosis Hyperthermia 2,3-DPG??
P50
Affinity? ?? O2 release to tissue O2 uptake? ??
??.
26.6mmHg
50
Transport of Resp. Gases in Blood

• Abnormal Ligands Abnormal Forms of Hemoglobins
• carbon monoxide, cyanide, nitric acid, ammonia ??
  ?? ?? hemoglobin? ??? ? ?? (shift to left)
• ?carbon monoxide 200-300? ??
• ?carboxyhemoglobin? ??
• methemoglobin heme? ?? iron? trivalent form??
  ??(?? ?? ??)
• methylene blue or ascorbic acid? methemoglobin??
  Hb??? ??? ????.
• abnormal hemoglobin protein subunit
  composition? variation? ?? ??
• fetal hemoglobin, hemoglobin A2. sick hemoglobin

51
Transport of Resp. Gases in Blood

• Oxygen Content
• Total O2 content solution? ?? ?? ?? hemoglobin?
  ?? ???? ?? ?
• oxygen content (0.003mL O2/dL blood/mmHg)
  PO2
•                          
  (SO2 Hb 1.31mL/dL blood)
• CaO2 19.5mL/dL blood     CvO2 14.8mL/dL blood
  
• ???, arteriovenous difference? ?? ? ??.
• CaO2 -CvO2 4.7mL/dL

52
Transport of Resp. Gases in Blood

• Oxygen Transport
• respiratory circulatory function? ?? ??
• Total oxygen delivery to tissue(DO2) arterial
  oxygen content cardiac output (QT)
• DO2 20mL O2/dL blood 50dLper blood/min
•           1000mL O2/min 
• Frick equation? ?? ??, ?? ?, ? ??? ?? ??? ????
•         oxygen consumption   VO2   QT (CaO2 -
  CvO2)
•                   CaO2    VO2        CvO2
•                               QT
• extraction fraction (CaO2- CvO2)/ CaO2 5/20
  25
• ??? hemoglobin? ??? ?? ? 25? ??, ???? ??? 25??,
  ??? 25??? ??
• delivery?? ?? ?????? ?? consumption? ??
  (extraction? ?? ??)

53
Transport of Resp. Gases in Blood

• Oxygen Store
• ???? ?? ?? ???? 1500ml
• 1. oxygen remaining in the lung (FRC) important
  store (80?? ????)
• 2. Hemoglobin? ??   ???    
• 3. dissoluted in body-fluid       ???
• ?? ?? oxygen content FiO2 FRC
• FiO2 0.21       FRC  2300mL  ? 90? ? severe
  hypoxemia ??. (O2 content480ml)
• FiO2 1          FRC  2300mL    ?  4-5? ?
  ????
• ??? ??? induction? preoxygenation? ??? ??.

54
Transport of Resp. Gases in Blood

• 2.Carbon Dioxide
• Transport 3 form
•      1.dissolved in solution, 
• 2. bicarbonate 
•      3.carbamino compound??? protein
• Dissolved Carbon Dioxide
• ???? ? ???   0.067mL/dL/mmHg

55
Transport of Resp. Gases in Blood

• Bicarbonate
• ?? ?? carbonic acid? bicarbonate? ??
•       H2O    CO2  ?  H2CO2  ?  H    HCO3-
• On the venous side of systemic capillary
• ???? carbonic anhydrase ? ??? CO2? ???? ???,
  ????? bicarbonate? ?? plasma? ?????
• ??? balance? ?? chloride? plasma?? ???? ????
• In pulmonary capillary
• chloride ion? ???? ?? ???, ???? bicarbonate ion?
  ??? CO2? ???? alveoli?? ????
• ?? Chloride or Hamburger shift ?? ??.
• Carbamino Compounds
•     R-NH2    CO2  ?  RNH-CO2-    H
• carbamino-hemoglobin? ??? CO2? ??
• deoxygenated hemoglobin? oxygenated hemoglobin?
  ?? 3.5??? CO2? ? ? ??

56
Transport of Resp. Gases in Blood

• Effects of Hemoglobin Buffering on Carbon Dioxide
  Transport
• Hemoglobin? histidine? ??? physiologic PH???
  buffer? ??
• Hb? oxygenated state? ?? ???? ????.
• Tissue capillary?? ???? ?? O2? ???? ??
• CO2   H2O    HbO2 ? HbH    HCO3-    O2
• Lung?? ??? ?? CO2? ???? ??
• O2    HCO3-    HbH  ?  H2O    CO2    HbO2
• Carbon Dioxide Stores
• ?? 120L in adult
• ?? dissolved CO2? bicarbonate ???
• ??? ?? ?? imbalance?, 20-30? ??? ??? ???
  equilibrium? ?? 

57
Control of Breathing

• brain stem ? respiratory center??? rhythmic
  neural activity? ??
• 1.Central Respiratory Center
• Medulla?? ????, two medullary group of neuron ?
  ??.
• 1.dorsal respiratory group inspiration ?? ???
• 2.ventral respiratory group expiration ?? ???
• basic rhythm
• dorsal group??? intrinsic, spontaneous discharge
  activity ?? dorsal ventral group??
  reciprocating activity? ??
• two pontine area? dorsal medulla? ??? ??
• ??? respiratory rate rhythm ????
• 1. lower pontine (apneustic) center  excitory
• 2. upper pontine (pneumotaxic) center 
  inhibitory

58
Control of Breathing

• 2.Central Sensor (Chemoreceptor)
• anterolateral surface of medulla
• respond to CSF (H)? ??
• effective in regulating PaCO2
• (BBB is permeable to dissolved CO2)
• PaCO2? ??? CSF H? ???? chemoreceptor? ??? ???,
  adjacent respiratory medullary center? ???
  alveolar ventilation(CO2 ??)? ??????? PaCO2? ???

59
Control of Breathing

• Lung Receptors
• carried centrally of vagus nerve
• stretch receptor smooth muscle of airway? ??
• lung? ??? ??? inspiration ?? (Herning-Breuer
  inflataion reflex)
• lung? ???? ?? ?? exhalation? ?? ?(deflation
  reflex)
• human? ?? minor role
• irritant receptor( in tracheobronchial mucosa)
• J (juxtacapillary) receptors (interstitial space
  within alveolar wall) interstitial space vol.
  ?? ?? ?? ????? ???? dyspnea? ???

60
Control of Breathing

• 4.Effects of Anestheisa on the Control of
  Breathing
• Hypoventilation? ???.
• Dual mechanism
• central depression of the chemoreceptor
• depression of external intercostal muscle
  activity
• hypoventilation? ??? ????? ?? 

61
Non-Respiratory Functions of the Lung

• Filtration Reservoir Function
• Filtration
• acts a filter for debris
• facilitates breakdown entrapped fibrin debris
• Reservoir function
• Pul. Circulation? systemic circulation? ??
  reservoir ??
• Metabolism
• 1.pneumocyte? surfactant?? ? ???, extrahepatic
  mixed-function oxidation? major portion? ??
• 2.neutrophil macrophage oxygen derived free
  radical
• 3.pulmonary endothelium metabolize a variety of
  vasoactive compound
• 4.angiotension?? angiotensin?? ??(surface of the
  pul. endotheium)