Presentation on theme: "Gas Exchange and Respiratory Function Part One"— Presentation transcript:
1 Gas Exchange and Respiratory Function Part One By Linda Self
2 Review of Terms Cyanosis—influenced by polycythemia and anemia Clubbing-Schamroth methodHemoptysisPerfusion—actual blood flow through the circulationVentilation----movement of gas into and out of the alveoliDiffusion—oxygen and CO2 exchanged fromenvironment>trachea>bronchi>bronchioles and alveoliCompliance-measure of the elasticity, expandability, and distensibility of lungs, influenced by surfactant
3 Ventilation—Perfusion Ratios Normal lung is 1:1Shunts: when perfusion exceeds ventilation, a shunt exists. Blood bypasses the alveoli w/o gas exchange occurring.Pneumonia, atelectasis, tumors, mucous plugs
4 Ventilation-Perfusion Ratios cont. High ventilation-perfusion ratio---Dead spaceVentilation exceeds perfusionAlveoli do not have adequate blood supply for gas exchange to occurPulmonary emboli, pulmonary infarction, cardiogenic shock
5 Ventilation-Perfusion Ratios cont. Silent unit—absence of ventilation and perfusionSeen in pneumothorax and severe ARDS
6 Neurologic Control of Ventilation Phrenic nerveRespiratory center in medulla and ponsCentral chemoreceptors in medulla, influenced by chemical changes in csfPeripheral chemoreceptors in aortic arch and carotid arteries, respond first to changes in PaO2, then PaCO2 and pH
7 Gerontologic Considerations Decreased strength of respiratory musclesDecreased elasticityIncreased respiratory dead spaceDecreased number of ciliaDecreased cough and gag reflexIncreased collagen of alveolar walls
8 Respiratory Assessment Health HistoryRisk factors for respiratory disease-genetics, smoking, allergens, occupational and recreational exposureDyspnea, orthopneaCough, ?productiveChest painCyanosisLung soundsClubbing—indicates chronicity
9 Diagnostic Evaluation PFTs-assess respiratory function, screening, assess response to therapyFVC—vital capacity performed with a maximally forced expiratory effortForced expiratory volume—FEV1—volume of air exhaled in the specified time during the performance of forced vital capacity. FEV1 is volume exhaled in one second.FEV1/FVC%--ratio of timed forced exp. volume to forced vital capacity
10 Diagnostic Evaluation--ABGs 1. pH2. evaluate the PaCO2 and HCO3-3. Look to see if compensation has occurred. If CO2 is >40, respiratory acidosis; If HCO3- <24, metabolic acidosis; next look at value other than primary disorder, if moving in same direction as primary value, compensation is underway.
11 ABG’s continued Can have two acid-base disturbances at same time This can be identified when the pH does not explain one of the changes, e.g.,pH 7.2PaCO2 52HCO3 13Notice that oxygen level is not a component in determining the acid-base balance
12 ABGs cont.Normal values for arterial gases: , CO mm Hg, HCO mEq/L, O mm Hg, BE +/-2 mEq/Lsat >94%Mixed Venous Blood: , CO mm Hg, HCO mEq/L, O mmHg, BE +/- 2mEq/L, sat 60-80%See chapter 14 of text
13 AcidosisResults in decreased myocardial contractility and a decreased vascular response to catecholamines. May interfere with metabolism of certain medications
14 AlkalosisCan radically impair oxygen release from RBCs. For this reason, use bicarbonate infrequently in code situations
15 Other diagnostic studies Pulse oximetry—not reliable in severe anemia, high CO levels, or in shockCO2 monitoring—tells us ventilation to lungs is occurring, that CO2 is being transported to lungs, exp. CO2 indicates adequate ventilationCulturesImaging—chest xray, CT, MRI, lung scans (inject isotope, inhale radioactive gas), PETBronchoscopyThoracentesisothers
16 Sleep ApneaAssociated with frequent, loud snoring with breathing cessation for 10 seconds or long, at least 5 episodes per hour, followed by awakening by a snort when O2 levels dropMay be associated with obesityDecreased pharyngeal tone (related to alcohol, sedatives, neuromuscular disease)
17 Sleep ApneaDiagnosed by polysomnography (ECG, EEG, EMG, pulse oximetry)More common in menHigh risk for CAD, cerebrovascular disease and premature death.Results in hypoxia and hypercapnia which trigger sympathetic response. Can lead to dysrhythmias and elevated BP
19 Management Nurse educates patient Avoid alcohol and sedatives Weight lossCPAP or BiPAP—CPAP prevents airway collapse, BiPAP makes breathing easier and results in lower airway pressureUvulopalatopharyngoplastyTracheostomyProvigil, Provera, Diamox, Triptil may help
20 Cancer of the Larynx Squamous cell most common—95% Increasing in women More common in African AmericansMost common in individuals between years of ageCarcinogens—tobacco, alcohol, exposure to asbestos, wood dust, cement dust, tar products, leather and metalsMost often affects glottic area
21 Laryngeal Cancer Clinical manifestations Hoarseness of greater than two weeks durationPersistent coughSore throatDysphagiaDyspneaUlcerationFoul breathCervical adenopathyWeight lossDebilitation
22 Assessment and Diagnosis H&PLaryngoscopy with biopsy/staging of diseaseCT and MRI to assess adenopathy and further stageing
23 Laryngeal Cancer—Management Depends on staging of tumorOptions include surgery, radiation and chemotherapySometimes combination therapyEnsure any dental problems corrected, usually before other treatments
24 Surgical ManagementLaser surgery, supraglottic laryngectomy, hemilaryngectomy, total laryngectomyIn case of total laryngectomy, advanced cancer presentLaryngeal structures removed including portion of trachea. Results in permanent loss of voice and permanent tracheostomyOften will have radical neck dissection involves removal of sternocleidomastoid muscle, lymph nodes, jugular vein, surrounding soft tissue
25 Post-operative Care Usually ICU postop Monitor airway, VS, hemodynamic status and comfort levelMonitor for hemorrhageMonitor for infectionMonitor tracheal stomaHave extra trach at bedside (of same size!)
26 Post-operative Care May be on ventilator initially Will have trach Ensure humidity at all timesMay have split thickness skin graft or trapezius or pectoralis muscle grafts—ensure side of flap or graft not in dependent positionMay have PCANG, G tube or jejunostomy tube may be in place—nutrition importantSpeech rehab, esophageal speech, electrolaryngesSupport group
27 Patients with chronic obstructive pulmonary disorders COPD—nonreversibleIncludes emphysema and chronic bronchitisCan co-exist with asthmaPresent with s/s in middle life and incidence increases with ageFVC and FEV1 decreased
28 Chronic Bronchitis Disease of airways Increased mucous production, decreased ciliary activity, inflammation, reduced alveolar macrophage function
29 EmphysemaLobule—physiologic unit of lung consisting of bronchiole and its branches (alveolar ducts, sacs and alveoli)Two types—panlobar and centrilobularIn Panlobartype—destruction of bronchiole, alveolar duct and alveoli; little inflammation, hyperexpanded chest, work on exhalationCentrilobar type—derangement of the V/Q ratios, chronic hypoxemia, hypercapnea, polycythemia and right sided heart failureSee p. 688 for schematic
30 Emphysema Risk factors include: Cigarette smoking Occupational dusts, chemicals, pollutionDeficiency of alpha1-antitrypsin, protective enzyme that protects lung parenchyma from injury---seen in Caucasians
31 COPD clinical manifestations Chronic cough, sputum production, and dyspnea on exertion (DOE)Weight loss commonIncreased number of respiratory infectionsIn primary emphysema, will have “barrel chest”
32 Diagnosis of COPD Thorough H&P Spirometry to evaluate airflow obstructionFEV1/FVC will be less than 70%Reversibility will be testedChest xrayABGsScreening for alpha1-antitrypsin deficiencyClassified by five stages—0 through IV (see p. 690)
33 Medical Management Smoking cessation will slow progression May use Chantix, Wellbutrin, nortriptyline, clonidineBronchodilators—beta agonists, anticholinergics, methyxanthines, combinations, nebulized medications, inhaled and systemic corticosteroidsInfluenza and pneumococcal vaccinesOxygen therapy—usually started in severe COPDHigh fat, low CHO diet
34 Oxygen Therapy in COPDPreviously felt that high levels of O2 affected hypoxic driveNow thought that Haldane effect relates to ability of hgb to carry O2 and CO2. With increased levels of O2, increased saturation, increased CO2 load w/o being able to expel it. So, increased hypercapnia.
35 Surgical ManagementBullectomy—have blebs or enlarged airspaces that do not contribute to ventilationLung volume reduction surgery—may improve quality of life but not life expectancyLung transplantation
36 Nursing Management Key is education Breathing exercises Inspiratory muscle training—breathe against a set resistanceActivity pacingSelf-care activitiesPhysical conditioningOxygen txNutritional therapyCoping measures
37 BronchiectasisChronic, irreversible dilation of the bronchi and bronchiolesCaused by: inflammation d/t recurrent infections damaging bronchial walls, thick sputum and decreased mucociliary clearance; genetic disorders like CF, idiopathic causesResults in atelectasis, fibrosis, VQ mismatchR/O TB or other pathologyTx-chest PT, smoking cessation, continuous abx tx, possible surgical resection of affected areas
38 AsthmaChronic inflammatory disease characterized by mucosal edema, airway hyperreactivity, and mucous productionLargely reversibleAllergy is strongest predisposing factorPoorly controlled asthma can result in remodeling. Bronchial muscles and mucous glands enlarge, alveoli hyperinflate and subbasement fibrosis.
39 AsthmaCells that play role in inflammation of asthma include: leukotrienes, bradykinins, prostaglandins, mast cells, neutrophils, eosinophilsBeta receptor stimulation results in decrease of chemical mediators and causes bronchodilationThree most common symptoms of asthma are cough, dyspnea and wheezing
40 Asthma Family, environmental and occupational history is necessary Comorbid conditions like GERD, drug- induced asthma and allergic bronchopulmonary aspergillosis may be present
41 Asthma Triggers Complications—status asthmaticus Rescue and maintenance medicationsPeak flow monitoring—measure highest airflow during a forced expiration. See asthma action plan on p Height, age and sex are variables to consider in personal best determination.
42 Status AsthmaticusSevere and persistent asthma that does not respond to conventional therapy. Can be precipitated by infection, irritants, ASA or othersSevere bronchospasm with mucous plugging leading to asphyxiaLabored breathing, engorged neck veins, cough, wheezingABGs indicatedO2, IV fluids, burst of steroids, short acting corticosteroids, possibly magnesium sulfateNurse monitors, administers fluids and meds, ensures no irritants in environment
43 Atelectasis Closure of collapse of alveoli Often occurs in postoperative setting and in those who are immobilizedCan result from any obstruction that blocks air to and from alveoli
44 AtelectasisClinical manifestations—cough, sputum, low grade fever. In severe cases, tachycardia, tachypnea, central cyanosisChest xray may reveal patchy infiltrates, crackles will be heard over affected area, O2 saturation may be lower than 90%
45 AtelectasisPrevention—turning, mobilizing patient, deep breathing maneuvers, incentive spirometry, secretion management such as suctioning, nebulizers, chest PTManagement—IPPB, chest PT, nebulizer tx, bronchoscopy, possible ventilator support, thoracentesis
46 PneumoniaIs an inflammation of the lung parenchyma caused by microorganismsCommunity acquired—usually caused by: Strep pneumo, Hemophilus influenza, Legionella, Mycoplasma pneumoniae, Chlamydia, viralHospital acquired—Pseudomonas, Staph aureus, Klebsiella
47 PneumoniaPneumonia in the immunocompromised patient—Aspergillus, Pneumocystis, Mycobacterium tuberculosisAspiration pneumoniaIs the most infectious disease causing death in the United States
48 Pathophysiology of pneumonia Arises when normal flora has been aspirated, when host defenses are down or from bloodborne organisms that enter the pulmonary circulationAffects ventilation and diffusion—will have adequate perfusion but not ventilation
49 Risk factors for Pneumonia Conditions resulting in mucous obstruction (cancer, smoking, COPD)ImmunosuppressionProlonged immobilityDepressed coughNPO, ETT, NG or OG tubesAlcohol intoxicationAdvanced ageMedications that depress respirations
50 Clinical Manifestations of Pneumonia Not possible to diagnose a certain type by manifestations aloneMay be sudden in onset with fever, chills and pleuritic pain as seen in pneumococcal pneumoniaMay be gradual in onset with low grade fever, HA, pleuritic pain, myalgias and pharyngitisOrthopneaPurulent sputum
51 Diagnosis of Pneumonia HistoryPhysical examSputum culturesBlood culturesChest xrayPossible bronchoscopy depending on severity
52 Medical Management Antibiotic depending on Gram stain Often treat empirically, intervene promptlyCAP-tx with Zithromax, Biaxin, doxy, or fluoroquinolone. With comorbidities, may use Augmentin, Vantin, Ceftin, and a macrolide or doxy. Symmetrel for Flu A, Tamiflu for Flu A/B. Bactrim for PCP.
53 Medical Management cont. Hospital acquired—IV antibiotics such as second generation cephalosporins, carbapenems, fluoroquinolones. If MRSA, use vancomycin, Zyvox. For Pseudomonas, use Timentin, Unasyn, and an aminoglycoside.Viral pneumonia is supportive care only.Hydration is important in all types.
55 Gerontologic Considerations In elderly the classic s/s of cough, chest pain, sputum production and fever may be absentMay be difficult to distinguish heart failure from pneumoniaXrays particularly helpful in this population
56 Nursing the patient with pneumonia Frequent assessment—night sweats, fever, chills, cough, lung soundsEncourage hydration as hydration thins and loosens secretionsHumidification w/or w/o oxygenEncourage cough, chest physiotherapyPromote restMaintain nutritionPromote patient education
57 Respiratory Care Modalities Nasal cannula—up to 6L/min. Delivers up to 42% oxygenSimple mask—flow rate 6-8L/min. Delivers % oxygen.Partial rebreather mask—flow rate is 8- 11L/min. Delivers 50-75% oxygen.Nonrebreather mask—flow at 12 L/min. Delivers % oxygen.Venturi mask—4-6 L/min, 6-8 L/min. Deliver respective oxygen concentration of 24, 26, 28 or 30, 35, 40% oxygen. Most accurate delivery.
58 Respiratory Care Modalities OxygenHypoxemia—decrease in arterial oxygen tension in bloodHypoxia—decrease on oxygen supply to tissuesOxygen toxicity—can occur if delivering >50% for longer than 48h. Caused by free radical production.Signs/symptoms of oxygen toxicity— paresthesias, fatigue, refractory hypoxemia, alveolar atelectasis, alveolar infiltrates
59 Consider alveolar collapse with high levels of oxygen
60 TracheostomySurgical procedure in which an opening is made into the tracheaTracheostomy tubeTemporary or permanentUsed to bypass an upper airway obstruction, allow removal of tracheobronchial secretions, permit long term use of mechanical ventilation, to prevent aspiration in unconscious patient or to replace endotracheal tube
61 Complications of tracheostomy Bleeding, pneumothorax, air embolism, aspiration, subcutaneous or mediastinal emphysema, recurrent laryngeal nerve damageAirway obstruction from accumulation of secretions ,tracheoesophageal fistula, tracheal ischemia
62 Nursing Care of the Patient with Tracheostomy Initially, semi-fowler’s position to facilitate ventilation, promote drainage, minimize edema, and prevent strain on the suturesAllow method of communicationEnsure humidity to trachSuction secretions as neededManage cuff—usually keep pressure less than 25 mm Hg but more than 15 mm Hg to prevent aspiration
63 Endotracheal Intubation Pass ETT via nose or mouth into tracheaMethod of choice in emergency situationPassed with aid of a laryngoscopeETT generally has a cuff, ensure that cuff pressure is between mm Hg.Use warmed, humidified oxygenShould not be used for more than 3 week
64 Preventing Complications Associated with Endotracheal and Tracheostomy Tubes Administer adequate warmed humidityMaintain cuff pressure at appropriate levelSuction as neededMaintain skin integrityAuscultate lung sounds—ETT can lodge in right mainstem bronchusMonitor for s/s of infectionMonitor for cyanosisMaintain hydration of patientUse sterile technique when suctioning and performing trach careMonitor O2 sat
65 Mechanical Ventilation Used to control patient’s respirations, to oxygenate when patient’s ventilatory efforts are inadequate, to rest respiratory musclesCan be positive pressure or negative pressureKey for the nurse is assess patient—not the ventilator
66 Indications for Mechanical Ventilation PaO2 <50 mm Hg with FiO2 >0.60PaO2 >50 mm Hg with pH <7.25Vital capacity < 2 times tidal volumeNegative inspiratory force < 25 cm H20Respiratory rate > 35 bpm( *vital capacity is dependent on age, gender, weight and body build. Usually is twice tidal volume. If < 10mL/kg, will need respiratory assist)
67 Classification of Ventilators—Negative Pressure Used for patients with polio, muscular dystrophy, ALS, myasthenia gravisExamples include the iron lung chamber, pneumo wrap and tortoise shell (portable devices with rigid shell to create a negative pressure)
68 Ventilators—positive pressure Inflate lungs by exerting positive pressure on the airwayUsually requires trach or ETTUsed in home setting as wellPressure cycled, time cycled and volume cycledNoninvasive positive pressure ventilation is an option, does not require ETT
69 Positive Pressure Ventilators Pressure cycled ventilators—delivers air until reaches a preset pressure, then cycles off, then passive expirationCan vary as patient’s airway resistance or compliance changesVolume delivered thus will vary and may compromise ventilation
70 Positive Pressure Ventilators Time cycled rarely seen in adults (used in newborns and infants)Volume cycled—most common. Delivers a preset volume usually 8-10ml per kgNoninvasive positive pressure ventilation—CPAP and BiPAP. CPAP indicated for sleep apnea, BiPAP esp. useful to avoid intubating patients and in those with neuromuscular disorders, other conditions.
71 Ventilator Modes Assist control Intermittent mandatory control Synchronized intermittent mandatory ventilationPressure support—assists SIMV, applies pressure plateau to spont. resp. during inspiratory phaseNew modes incl. computerized systems
72 Initial Ventilator Settings Tidal volumeLowest concentration of oxygen to maintain PaO mm HgPeak inspiratory pressureMode—AC or SIMV, possibly PEEPSensitivity so that patient can trigger the vent. With minimal effortCheck ABGs after being on vent. for minutes
73 Remember………..If patient becomes agitated, confused, tachycardic, blood pressure increases for some unexplained reason, assess for hypoxia and manually ventilate on 100%.If patient’s heart rate slows and BP drops during suctioning, possible vagal stimulation. Stop suctioning and give 100% O2.
74 Bucking the ventilator Occurs when the patient’s inspiration and expiration are out of synch with the ventilatorAnxiety, hypoxia, increased secretions, hypercapnia, othersSedatives, muscle relaxants, paralytics may be necessary
75 Monitoring and Managing Potential Complications associated with the ventilator See handoutAlterations in cardiac functionBarotrauma and volutrauma resulting in pneumothoraxVagal stimulationPulmonary infections—use chlorhexidine gluconate in oral care
76 Weaning from the Ventilator—criteria for weaning Vital capacity—amount of air expired after maximum inspiration. Should be mL/kg.Maximum inspiratory pressure-used to assess the patient’s respiratory muscle strength—should be at least -20cm H20Tidal volume—volume of air that is inhaled or exhaled during effortless breath.
77 Weaning criteria cont.Minute ventilation—equals resp rate times tidal volume. Normal is 6 L/min.PaO2 greater than 60 mm Hg with FiO2 <50%, stable vital signs, adequate nutritional statusWould refrain from sedating patient during weaning
79 Risk factors for thoracic surgery related atelectasis and pneumonia Preop—age, obesity, poor nutritional status, smoking, preexisting lung disease, comorbid statesIntraoperative—thoracic incision, prolonged anesthesiaPostop—immobile, supine, inadequate pain management, prolonged intubation/ventilator, presence of NG tube, LOC, lack of education
80 Care of Patient after Thoracotomy Maintain airway clearancePositioning-lobectomy turn either side,pneumonectomy turn on affected side, segmental resection varies per doctorChest tube drainage/careRelieve painPromote mobilityMaintain fluid volume and nutrition
81 Care of Patient after Thoracotomy—monitor and manage potential complications Monitor respiratory statusVitalsFor dysrhythmiasFor bleeding, atelectasis and infectionMonitor chest tube drainage, for leaks, for tube kinks, for excessive drainage
82 Chest tube drainage system Based on three bottle systemDrainage chamberWater sealWet or dry suctionMonitor water seal for bubblingCheck for subq emphysemaGently milk tubeOcclusive dressingMonitor drainage