Pulmonary System (2) [Read-Only] - gsm.utmck.edugsm.utmck.edu/surgery/documents/PulmonarySystem.pdf · Rib CageRib Cage Natural position: ... UsuallythereisnoworkduringexpirationUsually

Pulmonary SystemPulmonary System

Thomas Gaines, MDThomas Gaines, MDCindy Talley MDCindy Talley MDCindy Talley, MDCindy Talley, MDFebruary 6, 2007February 6, 2007

What is the Function of the What is the Function of the Pulmonary System?Pulmonary System?Pulmonary System?Pulmonary System?

Pulmonary FunctionPulmonary FunctionPulmonary FunctionPulmonary Function

A i O2 f iA i O2 f i Attain O2 from environmentAttain O2 from environment Deliver O2 to circulatory systemDeliver O2 to circulatory system

R CO2 f h b dR CO2 f h b d Remove CO2 from the bodyRemove CO2 from the body AcidAcid--base balancebase balance PhonationPhonation PhonationPhonation OlfactionOlfaction Modification of inspired airModification of inspired airModification of inspired airModification of inspired air Pulmonary defensePulmonary defense MetabolismMetabolism

PULMONARY FUNCTIONPULMONARY FUNCTIONPULMONARY FUNCTIONPULMONARY FUNCTION

VENTILATIONVENTILATION Moving OMoving O22/CO/CO22 b/t lungs & environmentb/t lungs & environmentgg 22 22 gg

DIFFUSIONDIFFUSION Moving OMoving O22/CO/CO22 b/t lungs & capillariesb/t lungs & capillariesMoving OMoving O22/CO/CO22 b/t lungs & capillariesb/t lungs & capillaries

TRANSPORTTRANSPORT Moving OMoving O /CO/CO b/t capillaries & tissuesb/t capillaries & tissues Moving OMoving O22/CO/CO22 b/t capillaries & tissuesb/t capillaries & tissues

REGULATIONREGULATION

CONTENTSCONTENTSCONTENTSCONTENTS

VENTILATIONVENTILATION DIFFUSIONDIFFUSION STRUCTURE & FUNCTIONSTRUCTURE & FUNCTION PULMONARY FUNCTION TESTSPULMONARY FUNCTION TESTS PULMONARY FUNCTION TESTSPULMONARY FUNCTION TESTS MECHANICAL VENTILATIONMECHANICAL VENTILATION

VENTILATIONVENTILATIONVENTILATIONVENTILATION

What muscles work during What muscles work during normal quiet inspiration?normal quiet inspiration?normal quiet inspiration?normal quiet inspiration?


Normal quiet breathing is performed by Normal quiet breathing is performed by the diaphragm only.the diaphragm only.

Diaphragm contracts downDiaphragm contracts downDiaphragm contracts downDiaphragm contracts down Lengthens the chestLengthens the chest Increases negative pressureIncreases negative pressureIncreases negative pressureIncreases negative pressure Draws air into the lungsDraws air into the lungs


What muscles work during What muscles work during normal quietnormal quiet expirationexpiration??normal quiet normal quiet expirationexpiration??


There are NO muscles that WORK during There are NO muscles that WORK during normal quiet expiration.normal quiet expiration.

Expiration occurs when the diaphragm Expiration occurs when the diaphragm RELAXES or RELAXES or RECOILSRECOILS upwardupward shortens the chestshortens the chest reduces the negative pressurereduces the negative pressure expels the airexpels the air


What muscles assist with What muscles assist with heavy breathing?heavy breathing?heavy breathing?heavy breathing?

VENTILATIONVENTILATIONVENTILATIONVENTILATION Rib CageRib CageRib CageRib Cage Natural position: ribs slanted downNatural position: ribs slanted down External intercostal muscles contractExternal intercostal muscles contractInspirationInspirationpp

Rib cage elevatesRib cage elevates Pulls the sternum away from the spinePulls the sternum away from the spine Increases the AIncreases the A--P diameter by 20%P diameter by 20% Increases the AIncreases the A--P diameter by 20%P diameter by 20%

Internal intercostal muscles contractInternal intercostal muscles contractExpirationExpiration Rib cage depressesRib cage depresses Pulls the sternum downPulls the sternum down AA--P diameter decreasesP diameter decreases


Muscles of Heavy Inspiration: Raises the Rib CageMuscles of Heavy Inspiration: Raises the Rib Cage External IntercostalsExternal Intercostals SCM (lifts the sternum)SCM (lifts the sternum) Anterior Serratus (lifts the ribs)Anterior Serratus (lifts the ribs) Scalene Muscles (lifts 1Scalene Muscles (lifts 1stst two ribs)two ribs) Scalene Muscles (lifts 1Scalene Muscles (lifts 1stst two ribs)two ribs)

Muscles of Heavy Expiration: Depresses the Rib CageMuscles of Heavy Expiration: Depresses the Rib Cage Muscles of Heavy Expiration: Depresses the Rib CageMuscles of Heavy Expiration: Depresses the Rib Cage Abdominal RectiAbdominal Recti Internal IntercostalsInternal IntercostalsInternal IntercostalsInternal Intercostals


Muscles can change the Muscles can change the shape and therefore theshape and therefore theshape and therefore the shape and therefore the pressure inside the thoracic pressure inside the thoracic ppcavity to assist with breathingcavity to assist with breathing


Pleural PressurePleural Pressure Continual suction of excess fluid into lymphaticsContinual suction of excess fluid into lymphatics Normally a slightly negative pressureNormally a slightly negative pressure

--5 cm H5 cm H2200(The amount required to keep lungs open at the(The amount required to keep lungs open at the(The amount required to keep lungs open at the (The amount required to keep lungs open at the resting level)resting level)

Normal inspiration: Normal inspiration: ↑ ↑ pleural pressurepleural pressure--7.5 cm H7.5 cm H2200


Alveolar PressureAlveolar PressurePressure inside the lung alveoliPressure inside the lung alveoligg With no airflow and open glottis,With no airflow and open glottis,

alveolar pressure = atm pressure = 0alveolar pressure = atm pressure = 0alveolar pressure = atm pressure = 0alveolar pressure = atm pressure = 0

N l i i tiN l i i ti 1 H1 H 00 Normal inspirationNormal inspiration→→ --1 cm H1 cm H2200 Normal expiration→Normal expiration→ +1 cm H+1 cm H2200


Alveolar Pressure change of Alveolar Pressure change of --1 cm H1 cm H220 0 ANDAND

Pleural Pressure change of Pleural Pressure change of --2.5 cm H2.5 cm H2200

→Moves 500 mL air into the lungs→Moves 500 mL air into the lungs


Transpulmonary PressureTranspulmonary PressureAlveolar Pressure Alveolar Pressure –– Pleural PressurePleural PressureMeasure of the elastic forcesMeasure of the elastic forces

≈ Recoil Pressure≈ Recoil Pressure≈ Recoil Pressure≈ Recoil Pressure


What is the measure of how What is the measure of how well the lungs expand for thewell the lungs expand for thewell the lungs expand for the well the lungs expand for the pressure applied?pressure applied?p ppp pp


COMPLIANCECOMPLIANCE Normal compliance for the lung =Normal compliance for the lung =p gp g

200 ml / cm H200 ml / cm H2200

T F tT F t Two Factors:Two Factors: Elastic Forces of the Lung TissueElastic Forces of the Lung Tissue Elastic Forces of the Surface TensionElastic Forces of the Surface Tension Elastic Forces of the Surface TensionElastic Forces of the Surface Tension


Elastic Forces of Lung TissueElastic Forces of Lung Tissue

only 1/3 contribution to complianceonly 1/3 contribution to compliance

depends on elastin & collagen fibers in depends on elastin & collagen fibers in the lung parenchymathe lung parenchyma


Elastic Forces of Surface TensionElastic Forces of Surface Tension

2/32/32/3 contribution to compliance2/3 contribution to compliance

Wh t i S f T i ?Wh t i S f T i ?What is Surface Tension? What is Surface Tension?

Water on the surface sticks together byWater on the surface sticks together byWater on the surface sticks together by Water on the surface sticks together by contracting togethercontracting together

ex: Raindropsex: Raindropsex: Raindropsex: Raindrops


What about water in the alveoli??What about water in the alveoli??

The thin layer of water inside the alveoli:The thin layer of water inside the alveoli: contracts togethercontracts togethergg tries to push the air outtries to push the air out collapses the alveolicollapses the alveoli

Surface Tension Surface Tension ≈ Elastic Force≈ Elastic Force


What agent decreases the What agent decreases the surface tension insidesurface tension insidesurface tension inside surface tension inside alveoli??alveoli??


SurfactantSurfactantMade by Type II alveolar epithelial cellsMade by Type II alveolar epithelial cellsy yp py yp pContains: phospholipids, proteins, ionsContains: phospholipids, proteins, ionsKey Ingredients:Key Ingredients:Key Ingredients:Key Ingredients:

DipalmitoylphosphatidylcholineDipalmitoylphosphatidylcholineApoproteinsApoproteinsCalcium ionsCalcium ions


Dipalmitoylphosphatidylcholine:Dipalmitoylphosphatidylcholine: One portion hydrophilicOne portion hydrophilic——spreads over spreads over p y pp y p pp

alveolar wateralveolar water One portion hydrophobicOne portion hydrophobic——orients toward air orients toward air

in alveoliin alveoli Does not dissolve in fluidDoes not dissolve in fluid Decreases the normal surface tension by Decreases the normal surface tension by

1/12 to 1/21/12 to 1/2


Apoproteins & Calcium ionApoproteins & Calcium ion Alllow phospholipid to spread faster over Alllow phospholipid to spread faster over p p p pp p p p

alveolar surface.alveolar surface. Surfactant not functional without themSurfactant not functional without them


Surface TensionSurface Tension

Pure WaterPure Water 72 dynes / cm72 dynes / cm AlveoliAlveoli 50 dynes / cm50 dynes / cmAlveoliAlveoli 50 dynes / cm50 dynes / cm Alveoli w/ SurfactantAlveoli w/ Surfactant 55--30 dynes / cm30 dynes / cm


Factors of InspirationFactors of Inspiration MusclesMuscles

Factors of ExpirationFactors of Expiration Collapse PressureCollapse Pressure Surface TensionSurface Tension Pleural PressurePleural Pressure

Alveolar PressureAlveolar Pressure ComplianceCompliance

Surface TensionSurface Tension Recoil PressureRecoil Pressure MusclesMuscles

ComplianceCompliance SurfactantSurfactant

MeasuresMeasures Lung Volumes / CapacitiesLung Volumes / Capacities Minute Ventilation Minute Ventilation Alveolar VentilationAlveolar Ventilation Alveolar VentilationAlveolar Ventilation Dead SpaceDead Space


Collapse PressureCollapse Pressure= = 2 x Surface Tension2 x Surface Tension = 4 cm H= 4 cm H220022

RadiusRadius

The smaller the alveolus, the greater the The smaller the alveolus, the greater the collapse pressurecollapse pressurep pp p


In premature babies:In premature babies: Alveoli are usually ¼ the normal sizeAlveoli are usually ¼ the normal size

S f / 6S f / 6thth && thth Surfactant is secreted b/t 6Surfactant is secreted b/t 6thth & 7& 7thth gestational gestational monthmonth

Therefore a premature baby could have aTherefore a premature baby could have a Therefore, a premature baby could have a Therefore, a premature baby could have a collapse pressure of > 30 mm Hgcollapse pressure of > 30 mm Hg

RESPIRATORY DISTRESS SYNDROME OF RESPIRATORY DISTRESS SYNDROME OF THE NEWBORNTHE NEWBORN


Compliance of LungCompliance of Lung--Thorax system is = Thorax system is = ½ that of lungs alone (200 ml / cm H½ that of lungs alone (200 ml / cm H220) 0)

110 ml / cm H110 ml / cm H2200110 ml / cm H110 ml / cm H220 0

Th f it t k 2 th fTh f it t k 2 th fTherefore, it takes 2x the energy for Therefore, it takes 2x the energy for normal inspirationnormal inspiration


Compliance WorkCompliance Work

Tissue Resistance WorkTissue Resistance Work

Airway Resistance WorkAirway Resistance Work Airway Resistance WorkAirway Resistance Work


Compliance WorkCompliance Work

Overcomes Overcomes elastic forceselastic forces

== ∆∆ Volume xVolume x ∆∆ PressurePressure = = ∆∆ Volume x Volume x ∆∆ PressurePressure22


Tissue Resistance WorkTissue Resistance Work

Overcomes the Overcomes the viscosityviscosity of the lungs of the lungs

Airway Resistance WorkAirway Resistance Work

Overcomes Overcomes resistance to airflowresistance to airflow thru thru respiratory passagewaysrespiratory passageways


Usually compliance >> airway > tissue Usually compliance >> airway > tissue resistance workresistance work

Usually there is no work during expirationUsually there is no work during expiration Usually there is no work during expiration…Usually there is no work during expiration… Heavy Breathing: Heavy Breathing: ↑↑airway resistance work↑↑airway resistance work Pulmonary disease: all work ↑Pulmonary disease: all work ↑ Pulmonary disease: all work ↑Pulmonary disease: all work ↑ Fibrosis: ↑ compliance & tissue resistance workFibrosis: ↑ compliance & tissue resistance work Airway Obstruction: ↑ airway resistance workAirway Obstruction: ↑ airway resistance work Airway Obstruction: ↑ airway resistance workAirway Obstruction: ↑ airway resistance work Asthma: ↑ airway resistance work in expiration Asthma: ↑ airway resistance work in expiration

> inspiration> inspirationpp


MeasurementsMeasurements

Volumes (4)Volumes (4)

Capacities (4)Capacities (4)


What are the four lung What are the four lung volumes?volumes?volumes?volumes?


Tidal Volume (TV or VTidal Volume (TV or VTT)) Normal breathNormal breath 500 ml500 ml

Inspiratory Reserve Volume (IRV)Inspiratory Reserve Volume (IRV) Maximum Inspiration p VMaximum Inspiration p VTT 3000 ml3000 ml

Expiratory Reserve Volume (ERV)Expiratory Reserve Volume (ERV) Maximum Expiration p VMaximum Expiration p V 1100 ml1100 ml Maximum Expiration p VMaximum Expiration p VTT 1100 ml1100 ml

Residual Volume (RV)Residual Volume (RV)( )( ) Air left in lungs p ERVAir left in lungs p ERV 1200 ml1200 ml


What are the four lung What are the four lung capacities?capacities?capacities?capacities?

VENTILATIONVENTILATIONVENTILATIONVENTILATION Capacities are combos of lung volumesCapacities are combos of lung volumes

Inspiratory Capacity (IC)Inspiratory Capacity (IC) VVTT + IRV+ IRV 3500 ml3500 ml

Functional Residual Capacity (FRC)Functional Residual Capacity (FRC) ERV + RVERV + RV 2300 ml2300 ml

Vital Capacity (VC)Vital Capacity (VC) IRV + VIRV + V + ERV+ ERV 4600 ml4600 ml IRV + VIRV + VTT + ERV+ ERV 4600 ml4600 ml

Total Lung Capacity (TLC)Total Lung Capacity (TLC) IRV + VIRV + VTT + ERV + RV+ ERV + RV 5800 ml5800 ml


Mi V il i (Mi V il i (VV ) V) V RRRR Minute Ventilation (Minute Ventilation (VVEE) = V) = VTT x RRx RRNormal = 6 L / minNormal = 6 L / min

Alveolar Ventilation (Alveolar Ventilation (VVAA)) Normal tidal volume gets most of the air only to the Normal tidal volume gets most of the air only to the

terminal bronchiolesterminal bronchiolesterminal bronchiolesterminal bronchioles

The velocity of the air molecules moving a short The velocity of the air molecules moving a short distance to the alveoli occurs by diffusiondistance to the alveoli occurs by diffusiondistance to the alveoli occurs by diffusiondistance to the alveoli occurs by diffusion

Rate at which new air reaches respiratory Rate at which new air reaches respiratory bronchiolesbronchiolesbronchiolesbronchioles


Alveolar VentilationAlveolar Ventilation= RR x (V= RR x (VTT –– VVDD))(( TT DD))

Normal = 4200 ml / minNormal = 4200 ml / min

One of the major factors determining concentration One of the major factors determining concentration of Oof O22 and COand CO22 in the alveoliin the alveoli


Dead Space (VDead Space (VDD))

Dead Space AirDead Space Air Air that stays in the nose, pharynx, trachea, Air that stays in the nose, pharynx, trachea,

terminal bronchiolesterminal bronchioles Dead SpaceDead Space Respiratory passages where no gas exchange Respiratory passages where no gas exchange

occursoccurs Normal VNormal V is 150 ml (increasing with age)is 150 ml (increasing with age) Normal VNormal VDD is 150 ml (increasing with age)is 150 ml (increasing with age)


Anatomic Dead SpaceAnatomic Dead Space Volume of the respiratory passages not in Volume of the respiratory passages not in p y p gp y p g

the gas exchange areasthe gas exchange areas

Physiologic Dead SpacePhysiologic Dead Space Additional volume of air in gas exchangeAdditional volume of air in gas exchangeAdditional volume of air in gas exchange Additional volume of air in gas exchange

areas that are not functionalareas that are not functional


What conditions can increase What conditions can increase the physiologic dead space?the physiologic dead space?the physiologic dead space?the physiologic dead space?


Things that decrease perfusion:Things that decrease perfusion: Pulmonary EmbolusPulmonary Embolusyy Pulmonary HTNPulmonary HTN Decreased Cardiac OutputDecreased Cardiac Outputpp High PEEPHigh PEEP ARDSARDSARDSARDS

Causes high PCauses high P COCO22Causes high PCauses high PaaCOCO22


Alveolar VentilationAlveolar Ventilation= RR x (V= RR x (VTT –– VVDD))(( TT DD))

Normal = 4200 ml / minNormal = 4200 ml / min

One of the major factors determining concentration One of the major factors determining concentration of Oof O22 and COand CO22 in the alveoliin the alveoli


Factors of InspirationFactors of Inspiration MusclesMuscles

Factors of ExpirationFactors of Expiration Collapse PressureCollapse Pressure Surface TensionSurface Tension Pleural PressurePleural Pressure

Alveolar PressureAlveolar Pressure ComplianceCompliance

Surface TensionSurface Tension Recoil PressureRecoil Pressure MusclesMuscles

ComplianceCompliance SurfactantSurfactant

MeasuresMeasures Lung Volumes / CapacitiesLung Volumes / Capacities Minute Ventilation Minute Ventilation Alveolar VentilationAlveolar Ventilation Alveolar VentilationAlveolar Ventilation Dead SpaceDead Space



DIFFUSIONDIFFUSIONDIFFUSIONDIFFUSION

Gas Exchange between alveoli and Gas Exchange between alveoli and capillariescapillaries

Hydrostatic Pressure difference betweenHydrostatic Pressure difference betweenHydrostatic Pressure difference between Hydrostatic Pressure difference between the apex and the base of the lungthe apex and the base of the lung

≈ 23 mm Hg difference≈ 23 mm Hg difference≈ 23 mm Hg difference≈ 23 mm Hg difference


Three Zones of Blood FlowThree Zones of Blood Flow

ZONE 1ZONE 1——No Flow: PNo Flow: PAA > P> Paa

ZONE 2ZONE 2——Intermittent Flow: SBP > PIntermittent Flow: SBP > PAA but but DBP < PDBP < PAA

ZONE 3ZONE 3——Continuous Flow: PContinuous Flow: Paa > P> PAA


Exercise increases blood flow to the top Exercise increases blood flow to the top of the lung ~ 700of the lung ~ 700--800% and to the bottom 800% and to the bottom of the lung ~200of the lung ~200--300% creating 300% creating equalization.equalization.

The entire lung becomes Zone 3 bloodThe entire lung becomes Zone 3 bloodThe entire lung becomes Zone 3 blood The entire lung becomes Zone 3 blood flowflow


V/Q RatioV/Q Ratio Usually 0.8 to 1.2Usually 0.8 to 1.2 If V/Q ratio increases: (vice versa)If V/Q ratio increases: (vice versa) If V/Q ratio increases: (vice versa)If V/Q ratio increases: (vice versa)

There is more O2 in the alveoli that are not delivered to the There is more O2 in the alveoli that are not delivered to the blood volumeblood volume

↑P↑P OO and ↓Pand ↓P COCO ↑P↑PAAOO2 2 and ↓Pand ↓PAACOCO22

ShuntShunt Perfused, but not ventilatedPerfused, but not ventilated,, Mixed venous blood from the right heart shunted to Mixed venous blood from the right heart shunted to

the left heart without gas exchangethe left heart without gas exchange Not correct by administration of oxygenNot correct by administration of oxygen Not correct by administration of oxygenNot correct by administration of oxygen


Si il l l i h b/ OSi il l l i h b/ O d COd CO Similar molecular weights b/t OSimilar molecular weights b/t O22 and COand CO22 Diffusion rate of ODiffusion rate of O2 2 in the gaseous phase is 1.2 in the gaseous phase is 1.2

x that of COx that of CO22x that of COx that of CO22 Diffusion rate of CODiffusion rate of CO22 in the liquid phase is 20 x in the liquid phase is 20 x

that of Othat of O22COCO ffff COCO22 diffuses until the partialdiffuses until the partial--pressure gradient pressure gradient is equalizedis equalized

OO22 diffuses into the blood combining with Hbdiffuses into the blood combining with HbOO22 diffuses into the blood combining with Hb diffuses into the blood combining with Hb maintaining the original partialmaintaining the original partial--pressure pressure gradient to saturate all the Hbgradient to saturate all the Hb


Fick’s LawFick’s Law

Rate of Gas Diffusion = Rate of Gas Diffusion = Area x Gas Diffusion Coefficient x Area x Gas Diffusion Coefficient x

Pressure Gradient / Barrier ThicknessPressure Gradient / Barrier Thickness

VVgasgas = = A x DA x Dgasgas x x ∆∆PPTT


Easier to measure diffusion capacity of Easier to measure diffusion capacity of Carbon Monoxide than Oxygen:Carbon Monoxide than Oxygen: DLDLCOCO Divide uptake of CO by measure PDivide uptake of CO by measure PaaCOCO

B dB d Based onBased on Diffusing Capacity of AlveolarDiffusing Capacity of Alveolar--Capillary Capillary

MembraneMembraneMembraneMembrane HbHb--CO reactionCO reaction Pulmonary Capillary Blood FlowPulmonary Capillary Blood Flow


O2 content of bloodO2 content of blood

CC OO = (Hb x 1 34 x O= (Hb x 1 34 x O sat) + 0 0003 Psat) + 0 0003 P OOCCaaOO22 = (Hb x 1.34 x O= (Hb x 1.34 x O22sat) + 0.0003 Psat) + 0.0003 PaaOO22


Oxyhemoglobin Dissociation CurveOxyhemoglobin Dissociation Curve

OO22 % saturation% saturation vs Pvs PaaOO22

Function of Hb’s changing affinity for OFunction of Hb’s changing affinity for O22

Normal p50 = 50% ONormal p50 = 50% O22sat ~ 27 mmHgsat ~ 27 mmHg


Right Shift:Right Shift: Low pHLow pH High temperatureHigh temperature High pCOHigh pCO22

High levels of 2 3High levels of 2 3 DPG (DPG ( ↓ affinity of Hb for O↓ affinity of Hb for O )) High levels of 2,3High levels of 2,3--DPG ( DPG ( ↓ affinity of Hb for O↓ affinity of Hb for O22)) High ATPHigh ATP

Encourages OEncourages O22 offloading making it more available offloading making it more available for tissuefor tissue


Alveolar gas equationAlveolar gas equation

PPAAOO22 = P= PIIOO22 –– PPAACOCO22/0.8 + F/0.8 + F

AA--a gradient equationa gradient equation

PP(A(A--a)a)OO22 = P= PAAOO2 2 –– PPaaOO22


Causes of HypoxemiaCauses of Hypoxemia V/Q mismatch (most common)V/Q mismatch (most common)( )( ) ShuntShunt ↓ P↓ PAAOO22↓↓ AA 22

HypoventilationHypoventilation ↑ Diffusion gradient↑ Diffusion gradient↑ Diffusion gradient↑ Diffusion gradient



AirwaysAirways----NasopharynxNasopharynxAirwaysAirways----NasopharynxNasopharynx

10,000 L of Toxic, Infected, Irritating Air10,000 L of Toxic, Infected, Irritating Air Functions: Functions: FilterFilter HumidifyHumidifyHumidifyHumidify WarmWarm

SNIFFINGSNIFFING: abrupt inspiration allowing: abrupt inspiration allowing SNIFFINGSNIFFING: abrupt inspiration allowing : abrupt inspiration allowing olfactory system to detect hazard before olfactory system to detect hazard before full breathfull breathfull breathfull breath

AirwaysAirways——Tracheobronchial TreeTracheobronchial Tree 23 Generations of airway branching23 Generations of airway branching Conducting Zone: 1Conducting Zone: 1--16 generations16 generations Transition Zone: 17Transition Zone: 17--19 generations19 generations Respiratory Zone: 20Respiratory Zone: 20--23 generations23 generations

Anatomic Dead SpaceAnatomic Dead Space = = Conducting Zone of the airway Conducting Zone of the airway Nasopharynx, Larynx, TracheaNasopharynx, Larynx, Trachea

Tracheobronchial TreeTracheobronchial TreeTracheobronchial TreeTracheobronchial Tree

Three groups of histology / functionThree groups of histology / function1.1. Trachea, major lobar, and segmental Trachea, major lobar, and segmental j gj g

bronchibronchi2.2. Membranous and terminal bronchiolesMembranous and terminal bronchioles3.3. Respiratory bronchioles, alveolar ducts, Respiratory bronchioles, alveolar ducts,

and alveolar air sacsand alveolar air sacs


Trachea, Major Lobar Bronchi & Trachea, Major Lobar Bronchi & Segmental BronchiSegmental Bronchi Cartilaginous WallsCartilaginous Walls Ciliated, Pseudostratified, Columnar Ciliated, Pseudostratified, Columnar , ,, ,

EpitheliumEpithelium MucusMucus--secreting goblet cellssecreting goblet cells MUCOCILIARY ESCALATORMUCOCILIARY ESCALATOR Submucosal glandular cells secrete Submucosal glandular cells secrete gg

lactoferrin (bacteriostatic agent)lactoferrin (bacteriostatic agent)


Membranous and Terminal BronchiolesMembranous and Terminal Bronchioles No cartilageNo cartilagegg Large amt of smooth muscle & elastic fibersLarge amt of smooth muscle & elastic fibers Neuroendocrine (APUD) cellsNeuroendocrine (APUD) cells( )( ) Serotonin, Dopamine, Norepinephrine, VIPSerotonin, Dopamine, Norepinephrine, VIP

Mast cellsMast cells Autonomic Nervous SystemAutonomic Nervous System


Mast cellsMast cells Histamine, Lysosomal Enzymes, Histamine, Lysosomal Enzymes,

L k t i Pl t l tL k t i Pl t l t A ti ti F tA ti ti F tLeukotrienes, PlateletLeukotrienes, Platelet--Activating Factor, Activating Factor, Chemotactic Factors, SerotoninChemotactic Factors, Serotonin BronchoconstrictionBronchoconstriction BronchoconstrictionBronchoconstriction Anaphylactic ReactionsAnaphylactic Reactions Immune/Inflammatory Responses of theImmune/Inflammatory Responses of theImmune/Inflammatory Responses of the Immune/Inflammatory Responses of the

lunglung Cardiopulmonary ReflexesCardiopulmonary Reflexesp yp y


Autonomic Nervous SystemAutonomic Nervous System VagusVagusBronchoconstriction, Bronchoconstriction,

Glandular SecretionGlandular Secretion SNSSNSBronchodilationBronchodilation

Inhibit Glandular SecretionInhibit Glandular Secretion αα--receptors: Bronchoconstrictionreceptors: Bronchoconstrictionββ t B h dil tit B h dil ti ββ--receptors: Bronchodilationreceptors: Bronchodilation Circadian Rhythm of Bronchial Smooth Circadian Rhythm of Bronchial Smooth

Muscles by PSNS: bronchoconstriction inMuscles by PSNS: bronchoconstriction inMuscles by PSNS: bronchoconstriction in Muscles by PSNS: bronchoconstriction in the a.m., bronchodilation in the p.m.the a.m., bronchodilation in the p.m.


BronchodilatorsBronchodilators SNSSNS

BronchoconstrictorsBronchoconstrictors PSNSPSNS

ββ--receptorsreceptors ↑CO↑CO22

↓O↓O

αα--receptorsreceptors thromboxane (plts)thromboxane (plts) histamine (mast cells)histamine (mast cells) ↓O↓O22 histamine (mast cells)histamine (mast cells) cool temperaturecool temperature arterialarterialarterial arterial

chemoreceptorschemoreceptors ↓CO↓CO22


Respiratory Bronchioles & AlveoliRespiratory Bronchioles & Alveoli Kohn poresKohn pores Clara cellClara cell Clara cellClara cell Type I pneumocytesType I pneumocytes

95% simple squamous layer on alveolar surface95% simple squamous layer on alveolar surface Primary diffusion surfacePrimary diffusion surface

Type II pneumocytesType II pneumocytes Cuboidal cellsCuboidal cells SurfactantSurfactant Regeneration of Type I pneumocytesRegeneration of Type I pneumocytes

Alveolar MacrophageAlveolar Macrophage Alveolar MacrophageAlveolar Macrophage

Chest WallChest WallChest WallChest Wall

Bony thoracic cage for protectionBony thoracic cage for protection Accessory muscles of respirationAccessory muscles of respirationy py p Maintains negative intrathoracic pressure Maintains negative intrathoracic pressure

by the intrinsic outward elastic recoil ofby the intrinsic outward elastic recoil ofby the intrinsic outward elastic recoil of by the intrinsic outward elastic recoil of the curved ribsthe curved ribs

PleuraPleuraPleuraPleura

P i l PlP i l Pl Parietal Pleura Parietal Pleura Corpuscular sensory endingsCorpuscular sensory endings Free somatic nerve endingsFree somatic nerve endingsFree somatic nerve endingsFree somatic nerve endings Primary Function: absorption via lymphaticsPrimary Function: absorption via lymphatics

Visceral PleuraVisceral PleuraPSNS SNS i tiPSNS SNS i ti PSNS, SNS innervationPSNS, SNS innervation

Primary Function: lubricationPrimary Function: lubrication Microvilli produce hyaluronic acidMicrovilli produce hyaluronic acid--glycoproteinglycoprotein

Pleural FluidPleural Fluid Typical Volume = 5Typical Volume = 5--15 ml15 ml Typical Turnover = 1Typical Turnover = 1--2 L / day2 L / day Typical Turnover = 1Typical Turnover = 1--2 L / day2 L / day

Pulmonary VasculaturePulmonary VasculaturePulmonary VasculaturePulmonary Vasculature

Pulmonary arteries Pulmonary arteries Entire right ventricle output of mixed venous Entire right ventricle output of mixed venous g pg p

bloodblood Distensible, lowDistensible, low--pressure systempressure system SNSSNS——vasoconstrictionvasoconstriction PSNSPSNS——vasodilationvasodilation Branches follow the airways into alveolarBranches follow the airways into alveolar--

capillary units for gas exchangecapillary units for gas exchange


Inspiration increases total pulmonary Inspiration increases total pulmonary vascular resistancevascular resistance Resistance is the result of passive forcesResistance is the result of passive forces DistensionDistensionDistensionDistension RecruitmentRecruitment——opening of new, previously opening of new, previously

closed capillaries from increased perfusion closed capillaries from increased perfusion p pp ppressure overcoming the critical opening pressure overcoming the critical opening pressurepressure


VasoconstrictorsVasoconstrictors HistamineHistamine

VasodilatorsVasodilators IsoproterenolIsoproterenol

ThromboxaneThromboxane HypoxiaHypoxia HypercapniaHypercapnia

AcetylcholineAcetylcholine PGEPGE11

PGIPGI HypercapniaHypercapnia Prostagladins F & EProstagladins F & E

PGIPGI22


Bronchial ArteriesBronchial Arteries Supplied from the aorta, intercostal arteriesSupplied from the aorta, intercostal arteriespppp Oxygenated arterial bloodOxygenated arterial blood Systemic pressureSystemic pressurey py p

Venous DrainageVenous Drainage Bronchial unsaturated blood drains toBronchial unsaturated blood drains to Bronchial unsaturated blood drains toBronchial unsaturated blood drains to AzygousAzygous--hemiazygous veinshemiazygous veins Pulmonary veins (anatomic rightPulmonary veins (anatomic right--toto--left shunt)left shunt)Pulmonary veins (anatomic rightPulmonary veins (anatomic right toto left shunt)left shunt)



PULMONARY FUNCTION PULMONARY FUNCTION TESTSTESTS Static Lung VolumesStatic Lung Volumes Decreased in restrictive lung dzDecreased in restrictive lung dz Increased RV, FRC, TLC in obstructive dz Increased RV, FRC, TLC in obstructive dz

(air trapping on expiration)(air trapping on expiration)D i L Ch t i tiD i L Ch t i ti Dynamic Lung CharacteristicsDynamic Lung Characteristics FEVFEV11 Decreased in COPDDecreased in COPD

FVCFVC FVCFVC FEVFEV11/FVC/FVC Decreased in COPD, Decreased in COPD,

Nl/Increased in Restrictive DzNl/Increased in Restrictive DzNl/Increased in Restrictive DzNl/Increased in Restrictive Dz

Pulmonary Function Pulmonary Function AssessmentAssessment Forced Vital Capacity (FVC)Forced Vital Capacity (FVC) Assessment of muscle strength & airway resistanceAssessment of muscle strength & airway resistance Measures ability for deep breathing & coughing Measures ability for deep breathing & coughing

postoperativelypostoperatively Forced Expiratory Volume (FEV)Forced Expiratory Volume (FEV) Forced Expiratory Volume (FEV)Forced Expiratory Volume (FEV) FEVFEV11/FVC/FVC Abnormal if < 0 7Abnormal if < 0 7 Abnormal if < 0.7Abnormal if < 0.7 Increased risk for major surgery if < 0.5Increased risk for major surgery if < 0.5

PULMONARY FUNCTION PULMONARY FUNCTION TESTSTESTS Requirement for thoracic surgeryRequirement for thoracic surgery Predicted postPredicted post--op valuesop values

FEVFEV11 > 0.8 (>40% predicted)> 0.8 (>40% predicted) DLDLCOCO > 11> 11--12 ml/min/mmHgCO (>50% predicted)12 ml/min/mmHgCO (>50% predicted) FVC > 1.5 LFVC > 1.5 L

PrePre--op valuesop values PCOPCO22 < 45< 45

POPO > 50> 50 POPO22 > 50> 50 VOVO22 max < 10max < 10

V/Q scan for lung contribution to FEVV/Q scan for lung contribution to FEV11 if < 2Lif < 2Lgg 1 1



MECHANICAL MECHANICAL VENTILATIONVENTILATION IndicationsIndications Dysfunction: Dysfunction: yy CNSCNS Chest WallChest Wall AirwayAirway Respiratory MusclesRespiratory Muscles

Al liAl li AlveoliAlveoli

MECHANICAL MECHANICAL VENTILATIONVENTILATION CNS dysfunctionCNS dysfunction GCS < 8 for airway protectionGCS < 8 for airway protectiony py p Narcotic OverdoseNarcotic Overdose Closed Head InjuryClosed Head Injury

Chest Wall dysfunctionChest Wall dysfunction Flail chestFlail chest Open PTXOpen PTX Marked ScoliosisMarked Scoliosis

MECHANICAL MECHANICAL VENTILATIONVENTILATION Airway DysfunctionAirway Dysfunction Facial TraumaFacial Trauma AnaphylaxisAnaphylaxis Foreign Body / MassForeign Body / Mass

Respiratory Muscle Fatigue / DiseaseRespiratory Muscle Fatigue / Disease Alveolar DysfunctionAlveolar Dysfunction Pulmonary EdemaPulmonary Edema PneumoniaPneumonia

MECHANICAL MECHANICAL VENTILATIONVENTILATION AlsoAlso PaCO2 > 45PaCO2 > 45 PaO2 < 55 (w/ supplemental oxygen)PaO2 < 55 (w/ supplemental oxygen) RR > 35RR > 35

Always accepted criteria: clinical judgmentAlways accepted criteria: clinical judgmentAlways accepted criteria: clinical judgmentAlways accepted criteria: clinical judgment

MECHANICAL MECHANICAL VENTILATIONVENTILATION ModesModes Assist Control (AC)Assist Control (AC)( )( ) Intermittent Mandatory Ventilation (IMV)Intermittent Mandatory Ventilation (IMV) Pressure Support (PS)Pressure Support (PS)pp ( )pp ( ) Pressure Control (PC)Pressure Control (PC)

MECHANICAL MECHANICAL VENTILATIONVENTILATION

ACAC ACAC VolumeVolume given at preset intervalsgiven at preset intervals Patient breath triggers volume deliveryPatient breath triggers volume delivery

IMVIMV IMVIMV VolumeVolume given at preset intervalsgiven at preset intervals Patient breath not mechanically supportedPatient breath not mechanically supported

S h tti t t kiS h tti t t ki Synchronous setting prevents stackingSynchronous setting prevents stacking PSPS

Positive Positive pressurepressure with each patient effortwith each patient effortV l d d PS ti t ff t liV l d d PS ti t ff t li Volume depends on PS, patient effort, complianceVolume depends on PS, patient effort, compliance

PCPC Peak Peak pressurepressure, inspiratory time, RR are set, inspiratory time, RR are set

V l d d liV l d d li Volume depends on complianceVolume depends on compliance Good for ARDS to decrease barotraumaGood for ARDS to decrease barotrauma

MECHANICAL MECHANICAL VENTILATIONVENTILATION PEEP (Positive EndPEEP (Positive End--Expiratory Pressure)Expiratory Pressure) Increases FRCIncreases FRC Improves complianceImproves compliance Best way to improve oxygenationBest way to improve oxygenationy p ygy p yg

Pressure SupportPressure SupportPressure SupportPressure Support Decreases Work of BreathingDecreases Work of Breathing

MECHANICAL MECHANICAL VENTILATIONVENTILATION To decrease PTo decrease PaaCOCO22:: Increase Tidal VolumeIncrease Tidal Volume Increase Respiratory RateIncrease Respiratory Rate

To increase PTo increase PaaOO22:: Increase PEEPIncrease PEEP Increase PEEPIncrease PEEP Increase FIncrease FiiOO22

MECHANICAL MECHANICAL VENTILATIONVENTILATION ComplicationsComplications Too much PEEPToo much PEEP

D P l dD P l d Decrease PreloadDecrease Preload Decrease CODecrease CO Decrease Renal Blood Flow & UOPDecrease Renal Blood Flow & UOPDecrease Renal Blood Flow & UOPDecrease Renal Blood Flow & UOP Increase PVRIncrease PVR

Too much OxygenToo much Oxygen Oxygen radical toxicity if FOxygen radical toxicity if FiiOO22 > 60> 60--70% for > 24 70% for > 24

hourshours BarotraumaBarotrauma BarotraumaBarotrauma Plateau pressure > 30, Peak pressure > 50Plateau pressure > 30, Peak pressure > 50

MECHANICAL MECHANICAL VENTILATIONVENTILATION ComplicationsComplications ET TubeET Tube Tracheal StenosisTracheal Stenosis Laryngeal InjuryLaryngeal Injury TracheomalaciaTracheomalacia TracheoTracheo--innominate Fistulainnominate Fistula

InfectionInfection InfectionInfection SinusitisSinusitis PneumoniaPneumonia PneumoniaPneumonia

MECHANICAL MECHANICAL VENTILATIONVENTILATION

W i PW i P MM Weaning ParametersWeaning Parameters

Settings:Settings:

Measurements:Measurements: VVEE < 10 L / min< 10 L / min VVTT > 5 mL / kg> 5 mL / kg

VC 10 L / kVC 10 L / kgg

FiO2 < 35%FiO2 < 35% PEEP 5PEEP 5 PS 5PS 5

VC > 10 mL / kgVC > 10 mL / kg Neg Insp Force > 20 cmH20Neg Insp Force > 20 cmH20

Vital Signs:Vital Signs: RR < 24RR < 24

ABG:ABG:

Vital Signs:Vital Signs: HR < 120HR < 120 O2 Sat > 93%O2 Sat > 93%

pH 7.35pH 7.35--7.457.45 pO2 > 60pO2 > 60 pCO2 < 50pCO2 < 50

Misc:Misc: Off pressorsOff pressors Follows commandsFollows commands Follows commandsFollows commands Can protect airwayCan protect airway

CONCLUSIONCONCLUSIONCONCLUSIONCONCLUSION


Documents

Pulmonary System (2) [Read-Only] - gsm.utmck.edugsm.utmck.edu/surgery/documents/PulmonarySystem.pdf · Rib CageRib Cage Natural position: ... UsuallythereisnoworkduringexpirationUsually