OXYGENATIONRespiratory System

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MedicalandSurgicalNursingRespiratorySystemLectureNotes

MS23

ANATOMYOFRESPIRATORY SYSTEM

OXYGENATON:thedynamicinteractionofgasesinthebodyforthepurposeofdeliveringadequateoxygenessentialforcellularsurvival

RESPIRATORY SYSTEMMAIN FUNCTION:GASEXCHANGE

I. Upper RespiratoryTractA. Functions1. Filtering2. Warming andmoistening3. HumidificationB. Parts1. Nose-madeupofframeworkofcartilages;dividedintoR andLbythe nasalseptum.2. ParanasalSinusesincludesfourpairofbonycavitiesthatarelinedwithnasalmucosaandciliatedepithelium.3. Tubernate Bones ( Conchae )4. Pharynxmuscularpassagewayforbothfoodandair Nasopharynx Oropharynx Laryngopharynx5. TonsilsandAdenoids6. Larynxvoice production,coughing reflexMade upofframeworkof: Epiglottisvalvethatcoverstheopeningtothe larynx during swallowing. Glottisopening betweenthe vocal cords Hyoidboneu shaped bone inneck Cricoidcartilage Thyroidcartilage,forms the Adams apple Arythenoidcartilage Speechproductionandcoughreflex Vocal cords7. Trachea - consistsofcartilaginousrings Passagewayofair Siteoftracheostomy(4th-6thtrachealring)

II. Lower respiratorytractA. Function: facilitates gasexchangeB. Parts1. Lungs,arepairedelasticstructureenclosedinthethoraciccage,whichisanairtightchamberwithdistensible walls. Right3lobes,10segments Left2lobes, 8 segments

ClientpostpneumonectomyaffectedsidetopromoteexpansionPostlobectomyunaffectedsideto promotedrainage Pleuralcavity Parietal Visceral PleuralFluid:preventspleuralfrictionrub(asseeninpneumonia andpleuraleffusion)

2. Bronchi LobarBronchi: 3R and2L Segmental Bronchi:10R and8L Subsegmental Bronchi3. Bronchioles Terminal Bronchioles RespiratoryBronchioles, consideredtobethe transitionalpassagewaysbetweentheconducting airways andthe gasexchange4. Alveoli functionalcellular unitsor gas-exchangeunitsofthe lungs. O2andCO2 exchange takes place Madeupofabout300millionTYPE 1 -provide structureto the alveoliTYPE 2 - secreteSURFACTANT,reducessurfacetension;increasesalveoli stability& prevents theircollapseTYPE 3alveolarcellmacrophages,destroysforeignmaterial,suchasbacteria

Lecithin SphingomyelinL/Sratio indicateslung maturity2:1 normal1:2 immature lungs

PULMONARY CIRCULATION-Providesforreoxygenationofbloodandrelease ofCO2 PULMONARYARTERIES,carrybloodfromthe hearttothe lungs.PULMONARYVEINS,isalargebloodvesselofthecirculatorysystemthatcarriesbloodfromthelungs tothe left atriumofthe heart.

RESPIRATORY MUSCLES PRIMARY:diaphragmandexternalintercostalmuscles ACCESORY:sternocleidomastoid(elevatedsternum),thescalenemuscles(anterior,middleandposteriorscalene)

PHYSIOLOGYOFRESPIRATORY SYSTEM

VENTILATION:Themovement ofair inand outofthe airways.

Thethoraciccavityisanairtightchamber.thefloorofthis chamber is the diaphragm. Inspiration:contractionofthediaphragm(movementofthischamberfloordownward)andcontractionoftheexternalintercostalmusclesincreasesthespaceinthischamber.loweredintrathoracicpressurecausesairtoenter throughthe airways andinflate the lungs. Expiration:withrelaxation,thediaphragmmovesupandintrathoracicpressureincreases.thisincreasedpressurepushesairoutofthelungs.expirationrequirestheelasticrecoil ofthe lungs. Inspirationnormallyis1/3oftherespiratorycycleandexpirationis2/3.

DRIVING FORCE FOR AIR FLOWAirflowdrivenbythepressuredifferencebetweenatmosphere(barometricpressure)andinsidethelungs(intrapulmonary pressure).

AIRWAY RESISTANCEResistanceisdeterminedchieflybytheradiussizeoftheairway.Causes ofIncreasedAirwayResistance1. Contraction ofbronchial mucosa2. Thickening ofbronchial mucosa3. Obstruction ofthe airway4. Loss oflung elasticity

RESPIRATION Theprocessofgasexchangebetweenatmosphericairandthebloodatthealveoli,andbetweenthebloodcellsandthe cells ofthe body. Exchangeof gasesoccurs becauseof differencesinpartialpressures. Oxygendiffusesfromtheairintothebloodatthealveolitobetransportedtothe cells ofthe body. Carbondioxidediffusesfromthebloodintotheairatthealveoli tobe removedfromthe body.

NEUROCHEMICALCONTROLMEDULLAOBLONGATArespiratorycenterinitiateseachbreathbysendingmessagestoprimaryrespiratory muscles over thephrenic nerve has inspirationand expirationcenters

PONShas2respirationcenters thatworkwiththeinspirationcentertoproducenormalrate ofbreathing1. PNEUMOTAXICCENTERaffectstheinspiratoryeffort bylimiting the volume ofair inspired2. APNEUSTICCENTERprolongsinhalation

NOTE:Chemoreceptorsresponds tochanges inph,increasedPaCO2= increaseRR

RESPIRATORYEXAMINATIONANDASSESSMENT

BackgroundinformationA. Abnormalpatternsofbreathing1. SleepApneacessationofairflowformore than10secondsmorethan10 times a night during sleepcauses:obstructive (e.g. obesitywithuppernarrowing,enlargedtonsils, pharyngeal soft tissue changes inacromegaly or hypothyroidism)2. Cheyne-Stokesperiodsofapnoea alternating withperiodsofhyperpnoaepathophysiology: delayinmedullarychemoreceptorresponseto bloodgaschangescauses leftventricular failure brain damage (e.g.trauma,cerebral,haemorrhage) highaltitude3. Kussmaul's(airhunger)deeprapidrespiration due tostimulationofrespiratorycentrecauses:metabolic acidosis (e.g.diabetes mellitus,chronic renalfailure)4. Hyperventilationcomplications: alkalosisandtetanycauses:anxiety5. Ataxic (Biot)irregular intiming and deepcauses:brainstemdamage6. Apneusticpost-inspiratorypauseinbreathingcauses:brain(pontine)damage

7. Paradoxicalthe abdomensuckswithrespiration(normally, itpouchesuotwarddue todiaphragmatic descent)causes:diaphragmaticparalysis

B. Cyanosis1. Refers toblue discoloration ofskinand mucousmembranes ,is due to presence ofdeoxygenatedhaemoglobinin superficial bloodvessels2. Centralcyanosis= abnromal amoutofdeoxygenatedhaemoglobinin arteries andthatblue discolorationispresent inpartsofbodywithgoodcirculationsuchastongue3. Peripheralcyanosis=occurswhenbloodsupplytoacertainpart ofbodyis reduced, andthetissue extractsmore oxygenfromnormal fromthecirculating blood,e.g.lips incoldweatherare oftenblue, butlips are spared4. Causes ofcyanosisCentralcyanosis decreasedarterialsaturation decreasedconcentrationofinspiredoxygen:highaltitude lung disease: COPDwithcorpulmoale,massive pulmonaryembolism right to leftcardiac shunt(cyanotic congenitalheartdisease) polycythaemia haemoglobinabnromalities (rare):methaemoglobinaemia,sulphaemoglobinaemiaPeripheral cyanosis allcauses ofcentralcyanosis causeperipheralcyanosis exposure tocold reducedcardiac output:left ventricular failure orshock arterial or venousobstructionPosition:patient sitting overedge ofbedGeneralappearance look for the following Dyspneanormal respiratoryrate< 14eachminutetachypnoea =rapidrespiratoryrateare accessory muscles being used(sternomastoids,platysma,strapmuscles ofneck)- characteristically,the accessory muscles cause elevation ofshoulderswithinspirationandaidrespirationbyincreasingchestexpansion Cyanosis Characterofcoughaskpatient tocoughseveraltimeslack ofusual explosive beginningmay indicatevocal cordparalysis (bovine cough)muffled,wheezyineffective coughsuggests airflowlimitationveryloose productive coughsuggestsexcessivebronchial secretionsdue to: chronicbronchitis pneumonia bronchiectasisdryirritating coughmayoccur with: chestinfection asthma carcinoma ofbronchus leftventricular failure interstitial lungdisease ACE inhibitors Sputumvolumetype (purulent,mucoid,mucopurulent)presence or absence ofblood? Stridorcroaking noiseloudeston inspirationis a signthat requires urgentattentioncauses: (obstructionoflarynx, tracheaor largebroncus) acute onset (minutes) inhaledforeign body acute epiglottitis anaphylaxis toxicgas inhalation gradual onset (days,weeks) laryngeal andpharyngealtumours crico-arytenoidrheumatoidarthritis bilateralvocal cordpalsy trachealcarcinoma paratrachealcompressionbylymph nodes post-tracheostomyor intubationgranulomata Hoarsenesscauses include: laryngitis laryngealnerve palsyassociatedwithcarcinoma oflung laryngealcarcinomaThe Hands Clubbingcommonlycause byrespiratorydisease (but NOTemphysema or chronicbronchitis)occasionally, clubbingis associatedwithhypertrophicpulmonaryosteoarthropathy(HPO) characterisedbyperiostealinflammationatdistal endsoflong bones,wrists,ankles,metacarpals andmetatarsals sweelling andtenderness overwrists andotherinvolvedareas

Stainingstainingoffingers- signofcigarette smoking (caused bytar,notnicotine) Wastingandweakness Pulse rate Flappingtremor(asterixis)- unreliablesignaskpatient to dorsiflexwrists andspreadoutfingers,witharms outstretchedflapping tremormayoccurwithsevere carbondioxideretention (severe chronic airflowlimitation)

The Face EyesHorner'ssyndrome? (constrictedpupil,partialptosisandlossofsweating whichcanbeduetoapical lung tumourcompressing sympathetic nerves inneck) Nosepolpys? (associatedwithasthma)engorgedturbinates? (variousallergicconditions)deviatedseptum? (nasal obstruction) Mouthandtonguelook forcentralcyanosisevidence ofupperrespiratorytract infection(a reddenedpharynx andtonsillarenlargementwithor without acoatingofpus)brokentooth- maypredispose to lung abscess orpneumonia sinusitis isindicatedbytendernessover the sinuses onpalpation some patients withobstructive sleepapnoea will beobesewitha receding chin, a smallpharynx anda shortthickneckThe Trachea causes oftrachealdisplacement:towardthesideofthelunglesion upperlobecollapse upperlobe fibrosis pneumonectomyupper mediastinalmasses,suchasretrosternalgoitre tracheal tug (finger restingontrachea feels itmoveinferiorlywitheachinspiration) is a sign ofgross overexpansionofthechestbecause ofairflowobstructionThe Chest: inspection Shape andsymmetryofchestBarrelshaped anteroposterior(AP)diameter is increasedcomparedwithlateraldiameter causes:hyperinflationdue toasthma,emphysema

Pigeonchest(pectuscarinatum) localisedprominence (outwardbowing ofsternumandcostalcartilages) causes:manifestationofchronicchildhoodillness (due torepeatedstrong contractions ofdiaphragm whilethoraxis stillpliable)rickets

Funnelchest(pectusexcavatum) developmentaldefect involvinga localiseddepressionoflower endofsternuminseverecases, lung capacitymaybe restricted

Harrison'ssulcus innardepressionoflower ribs justabove costalmarginsat site ofattachment ofdiaphragm causes:severe asthma inchildhoodricketsKyphosis,exaggeratedforwardcurvatureofspineScoliosis,lateral bowingKyphoscoliosis:causes: idiopathic (80%) secondarytopoliomyelitis(inflammationinvolvinggrey matter ofcord) (note:severe thoracic kyphoscoliosismayreducelungcapacityandincrease work ofbreathing)Lesionsofchest wall scars - previous thoracicoperations or chest drains for aprevious pneumothorax orpleuraleffusion thoracoplasty(was once performedto removeTB, butnolonger isbecause ofeffective antituberculosischemotherapy)invovledremoval oflarge number ofribs onone sidetoachieve permanentcollapse ofaffectedlung erythema andthickeningofskin mayoccur inradiotherapy; thereis a sharpdemarcationbetweenabnormal andnormalskinDiffuse swellingofchest wall and neck pathophysiology:airtrackingfromthelungs causes:pneumothoraxruptureofoesopahagusProminentveins cause:superiorvena caval obstructionAsymmetryofchest wallmovements assess this byinspectingfrombehind patient,lookingdownthe clavicles during moderate respiration-diminishedmovement indicates underlying lung disease the affectedside willshoweddelayedor decreasedmovement causes of reduced chestwallmovements onone side arelocalised:localisedpulmonary fibrosisconsolidationcollapse pleural effusionpneumothroaxcauses ofbilateral reduced chestwall movementsarediffuse: chronic airflowlimitation diffuse pulmonaryfibrosis

The Chest:palpation chestexpansionplace hands firmlyonchestwallwithfingers extendingaroundsidesofchest(fugyre 4.5)as patient takes a big breathin,the thumbsshould movesymmetricallyapart about5cmreducedexpansion onone side indicates alesiononthatsidenote: lower lobe expansionis testedhere;upper lobeistestedfor oninspection(asabove) apexbeat(discussedin cardiac section)for respiratorydiseases: displacementtowardsite oflesion- can be causedby:collapseoflower lobelocalisedpulmonary fibrosis displacementaway fromsite oflesion- can be causedby:pleural effusiontension pneumothorax apex beat is oftenimpalpable inachestwhichishyperexpandedsecondarytochronicairflowlimitation vocalfremituspalpate chestwallwithpalmofhandwhile patientrepeats"99"front and back ofchest are eachpalpatedin2comparablepositions with palms; inthis waydifferences invibrationonchestwallcanbe detectedcauses ofchange invocalfremitus arethe same as those forvocalresonance (see later) ribsgently compresschestwallanteroposteriorly andlaterallylocalisedpainsuggests aribfracture (maybesecondarytotrauma or spontaneous asa resultoftumourdeposition orbonedisease)The Chest:percussioncardiac dullness: area ofcardiac dullnessis uaully presentonleft sideofchest this maydecrease inemphysemaor asthmaThe Chest:auscultation breathsoundsintroductionone should usethediaphragmof stethoscope tolistentobreathsoundin eacharea, comparing eachsideremember tolistenhighupinto the axillaeremember tousebellofstethoscope to listentolungfromabove the claviclesquality ofbreathsoundsnormalbreat sounds are heardwithstethoscopeoverall parts ofchest,produced inairwaysrather thanalveoli(althoughonce theyhadbeenthoughttoarisefromalveoli(vesicles) andare therefore calledvesicular sounds) normal(vesicular)breathsoundsare louder andlongeroninspirationthan onexpiration;andthereis nogapbetweenthe inspiratoryandexpiratorysoundsbronchial breathsounds turbulence in large airways is heardwithoutbeing filteredbythe alveoli, and thereforeproducea differentquality; theyare heardoverthe trachea normally, butnotover the lungs are audible throughoutexpiration,and oftenthereis a gapbetweeninspirationandexpiration are heardoverareas ofconsolidationsince solidlung conducts the sound ofturbulence inmainairways toperipheral areas without filtering causes include: lung consolidation(lobarpneumonia)-common localisedpulmonary fibrosis- uncommonwithleft handonchestwall andfingers slightlyseparatedandalignedwithribs,themiddlefinger is pressedfirmlyagainstthe chest;padofright middlefinger is usedtostrike firmlythemiddle phalanxofmiddlefinger ofleft handpercussionofsymmetricalareas of: anterior (chest) posterior(back)(askpatient to move elbowsforwardacross the front ofchest- thisrotates the scapulaeanteriorly,i.e.moves itout oftheway) axillaryregion(side) supraclavicularfossapercussion over a solidstructure (e.g.liver,consolidatedlung)produces a dullnotepercusion over a fluidfilledarea (e.g. pleural effusion)produces an extremelydull (stony dull) notepercussion over thenormal lung produces a resonantnotepercussion over ahollowstructure (e.g.bowel,pneumothorax)produces a hyperresonsantnoteliverdullness: upperlevel ofliver dullnessisdeterminedbypercussingdownthe anteriorcehstinmid-clavicular line normally, upper level ofliver dullnessis 6thribinrightmid-clavicular line ifchest is resonant belowthis level,it is a sign ofhyperinflationusuallydue toemphysema,asthma pleural effusion(above the fluid)-uncommon collapsedlung (e.g.adjacenttoapleuraleffusion)-uncommon amphoric sound= whenbreathsoundsover alarge cavityhave anexaggeratedbronchialquality)intensityof breathsoundscauses ofreducedbreathsoundsinclude: chronic airflowlimitation(especiallyemphysema) pleural effusion pneumothorax pneumonia large neoplasm pulmonarycollapseadded(adventitious) soundstwotypes ofaddedsounds:continuous(wheezes) andinterrupted(crackles)wheezes maybe heardinexpiration or inspirationorboth pathophysiologyof wheezes- airway narrowing aninspiratorywheeze implies severe airwaynarrowing

causes of wheezes include: asthma (oftenhighpitched)-duetomusclespasm,mucosaloedema, excessivesecretions chronic airflowdiseases- duetomucosaloedema andexcessive secretions

TheAbdomen

pulmonarythromboembolismmarkedobesitysleepapnoeasevere kyphoscoliosis

-carcinoma causingbronchialobstruction-tends tocause a localisedwheeze whichismonophonic and does notclearwithcoughing

Other

palpate liverforenlargement duetosecondarydeposits oftumourfromlung, or rightheartfailure

crackles some terms not touse include rales (lowpitchedcrackles) andcreptitations(highpitchedcrackles) crackles areduetocollapse ofperipheralairways onexpirationandsudden opening oninspiration earlyinspiratorycrackles suggests diseaseofsmallairways characteristic ofchronic airflowlimitation are onlyheardinearlyinspiration lateor paninspiratorycrackles suggests disease confinedtoalveoli maybe fine,mediumor coarse fine crackles - typicallycaused bypulmonary fibrosis mediumcrackles- typicallycausedbyleftventricularfailure (due topresence ofalveolar fluid) coarse crackes -tendtochange withcoughing;occur withanydiseasethat leadstoretention ofsecretions;commonlyoccurinbronchiectasispleuralfrictionrub whenthickened,roughened pleuralsurfaces rubtogether, a continuous orintermittentgratingsoundmaybe heard suggestspleurisy,whichmaybesecondarytopulmonaryinfarctionorpnuemonia

vocalresonanancegives informationaboutlungs'abilitytotransmit soundsconsolidatedlung tendstotransmit highfrequencies sothat speechheard through stethoscope takes a bleetingquality(aegophony);whenapatient withaegophonysays"bee"it soundslike "bay"listenovereachpartofchest aspatient says"99";overconsolidatedlung,the numbers will become clearlyaudible; overnormal lung, thesoundis muffledwhispering pectoriloquy- vocalresonance isincreasedtosuchanextentthatwhisperedspeechis distinctlyheardThe Heartliepatient at45degreesmeasure jugular venous plse for right heartfailureexamine preacordium; payclose attentionto pulmonarycomponent ofP2(whichis bestheardat 2ndintercostalspace onleft) andshould not belouderthanA2; ifit islouder,suspectpulmonaryhypertensioncor pulmonale (also calledpulmonaryhypertensive heartdisease)maybedueto:chronic airflowlimitation(emphysema)pulmonary fibrosisPermberton'ssign askpatient toliftarmsoverhead look fordevelopment offacial plethora,inspiratorystridor,non-pulsatileelevation ofjugular venouspressure occurs invena cavalobstructionFeet inspectforoedema or cyanosis(clues ofcorpulmonale) look forevidence ofdeepveinthrombosisdRespiratoryrate onexercise andpositioning patients complaining ofdyspnoea should have theirrespiratoryratemeasuredatrest,atmaximaltoleratedexertionandsupine ifdyspnoeais notaccompaniedbytachypnoea whenapatient climbsstairs,one should considermalingering look forparadoxicalinwardmotion ofabdomenduring inspirationwhenpatient isuspine (indicatingdiaphragmatic paralysis)Temperature:fevermayaccompanyany acute or chronicchestinfection

DIAGNOSTIC EVALUATION

1. Skin Test:MantouxTestor TuberculinSkinTest

This is usedtodetermine ifapersonhas beeninfectedorhas beenexposed tothe TBbacillus. Thisutilizes the PPD(PurifiedProteinDerivatives). The PPD isinjectedintradermallyusuallyinthe inneraspect ofthe lowerforearm about4inches belowtheelbow. The test is read48to72hoursafter injection. (+)MantouxTestis induration of 10mm ormore. But for HIV positive clients,induration ofabout5mmisconsidered positive Signifiesexposure toMycobacteriumTuberclebacilli

2. Pulse Oximeter

Non-invasivemethodofcontinuously monitoringheoxygensaturationofhemoglobin Aprobeor sensor is attached to the fingertip,forehead,earlobeorbridgeofthenose Sensordetectschanges inO2satlevelsby monitoringlightsignalsgeneratedbythe oximeter andreflected bythe blood pulsing throughthe tissue at theprobeNormal SpO2=95% -100%