Pulmonary Review

From Iusmicm

Revision as of 21:25, 6 March 2012 by 134.68.138.157 (Talk)

Contents

Introduction

Approach to Shortness of Breath

Lung

  • Interstitial Lung Disease, What is it?
  • Lung Nodules/Cancer (#1 cause of cancer death)
    • What types are there?
    • How are they distinguished from one another?
  • Pneumonia
    • Types, risk factors, treatment
  • Atelectasis (collapse of the lung)
    • Shallow breathing,
    • Surfactant problems
    • Obstruction of airway (mucus, tumor)

Vascular

  • Pulmonary Hypertension
    • How do we diagnose it?
    • How do we define it?
    • What causes it?
  • Pulmonary Embolism
    • How do we diagnose it?
    • How do we treat it?

Airway

  • Airway obstruction “COPD”
    • Asthma
    • Emphysema
    • Chronic Bronchitis
  • How do we diagnose it?
  • How do we treat it?
  • How do we distinguish these from one another?

Mechanical

  • Neurologic ventilatory problems
    • How do we diagnose and treat them?
  • Pleural problems
    • What is the purpose of the pleura?
    • How do we define pleural effusions?

Miscellaneous

  • Peds (Dr. Howenstine)
    • Recognize common pediatric respiratory problems
  • Respiratory Failure (Dr. Carlos)
    • What are our options for the failing patient?
    • When and how do we intubate patients?
    • Exam prep
  • Case Conference
    • Putting it all together…real life cases.


History and Physical Exam

  • “One of the essential qualities of the clinician is interest in humanity, for the secret in the care of the patient is in caring for the patient.”


Know the key details of the pulmonary history and physical exam

  • History:
    • Shortness of breath: When, where, how long, triggers, relievers
    • Cough: Mucus?, blood?, timing?
    • Associated conditions:
      • Chest pain, dizziness, leg swelling, dysphagia
    • Social History:
      • Pets (birds, rodents, lizards, farm animals)
      • Occupation (silica, asbestosis, fumes, metals)
      • Travel
        • Tuberculosis (remember vets ~ Vietnam)
        • Long flights = immobility (DVT, PE)
      • Smoking
        • Calculate pack/years, quit? when?
        • Ex. smoked 2ppd x 15 years = 30 pk/year history
        • Remember 2nd hand exposures!
    • Family History:
      • Tuberculosis (exposure)
      • Lung Cancer (? Genetic)
      • Rheumatic diseases
      • COPD/Emphysema
      • Alpha-1-antitrypsin (< 50 yrs old)
  • Physical:
    • Inspection:
      • Nasal flaring, pursed lips, sentences, abd breathing
      • Accessory muscles (scalene, SCM contract)
      • Kyphoscoliosis, clubbing, edema
    • Palpation
      • Tactile fremitus (consolidation increases), effusion decreases
      • Trachea
    • Percussion (use your wrist!)
      • Side to side, hyper or hypo
    • Auscultation
      • Egophony (“eeee” --- “aaaa” = consolidation)
      • Listen here
      • Dullness + crackles + increased breath sounds + increased fremitus = consolidation
      • Dullness + decreased breath sounds + decreased fremitus = effusion
      • Dullness + absent breath sounds = atelectasis


Interpret basic acid-base disorders

  • ABG gives you: pH, pCO2, and pO2
  • Anion gap can be calculated = Na - Cl + CO2
    • Requires CO2 value from serum chemistries


  • pH interpretation of ABG:
    • acute: decrease of pH by 0.08 generally indicates an increase of PaCO2 of 10 (and vice versa)
    • chronic: decrease of pH by 0.03 generally indicates an increase of PaCO2 of 10 (and vice versa)
      • includes a 5 pt bicarb rise for every 10 mm pCO2 rise
    • see table
Disorder PaCO2 pH HCO3 Anion Gap Common Causes
Metabolic acidosis low low up or down MULEPAKS (AG high), HARDUP (AG normal)
Metabolic Alkalosis high high contraction alkalosis, diuretics, corticoisteroids, gastric suctioning, vomiting, hypderaldosterone (Cushing's, Bartter's syndrome, severe K depletion)
Respiratory acidosis high low CNS depression, chest bellows dysfxn (Guillan-Barre, MG), lung or upper airway disease (COPD, asthma, pulm edema)
Respiratory alkalosis low high hypoxemia, altitude, anxiety, sepsis, pneumonia, mild asthma, early pulm edema, PE


ABG Interpretation

  • ABG gives you pH, pCO2, and pO2.
    • pCO2 tells you about ventilatory problems.
    • pO2 tells you about oxygenation problems.

Oxygenation Failure

  • Oxygenation failure is defined as an elevated A-a gradient.
    • A-a gradient: difference between alveolar oxygen and arterial oxygen = PiO2 - (pCO2 / R) - pO2
      • PiO2: pressure of oxygen in the inspired air; room air is 21% at 760 barometric pressure so around 150; can be diff on a ventilator.
      • pCO2: pressure of CO2 in the blood; from the ABG
      • R: respiratory quotient; assume 08
      • pO2: pressure of oxygen in the arterial blood; from ABG
    • Normal A-a gradient = (pt age / 4) + 4


  • To quantify the oxygenation problem (once we have calculated an elevated A-a gradient), we compare SaO2 to PaO2 and PaO2 to FiO2.
    • SaO2 = oxygen saturation; obtained via pulse oximetry
    • PaO2 = dissolved oxygen; obtained via ABG
    • FiO2 = inspired oxygen; assumed to be 21% on room air but can be whatever you set on a mask / cannula


  • SaO2 : PaO2: a measure of oxygen on hemoglobin to oxygen in the blood
    • high ratio means that....


  • PaO2:FiO2 = a measure of blood oxygen to alveolar oxygne.
    • A normal PaO2:FiO2 is calculated via the A-a gradient: A-a = FiO2 - (pCO2 / R) - pO2, so FiO2 / pO2 =
    • The worse the oxygenation issue, the lower the ratio.
    • That is, the worse the ability of the lungs to move oxygen from the alveolar air to the blood, the lower the PaO2 relative to a (practically) stable FiO2.


Diagnose pneumothorax, pleural effusion, and atelectasis on exam or xray (know what to look for!)

  • Pneumothorax
    • hypodense areas, lack of blood vessels, trachea deviates away from lesion
    • chest tube w/ suction to pull air off


  • Pleural effusion
    • poor phrenic angles, uni/bi lateral density, decubitus view (free, loculated, fluid air level)
    • trachea deviates away from lesion
    • hemithorax on lesion side increases
    • dullness, decreased breath sounds on lesion side
    • decreased fremitus on lesion side
    • thoracentesis


  • Atelectasis
    • trachea shifts toward side with atelectasis
    • hemithorax decreases on lesioned side
    • clear mucus plug with bronchoscopy

Know how to treat a pneumothorax, atelectasis secondary to mucus plug, and pleural effusion

  • see above

Know basic bronchoscopic indications

  • Indications for bronchoscopy:
    • Bronchoalveolar lavage (cultures, cell counts)
    • Evaluate for bleeding or obstruction or burn
    • Clear out mucus plugs “a snot bronch”
    • Biopsy of lung lesion
    • Biopsy of lymph node (EBUS)
      • Mediastinal staging of cancer
      • Diagnosis of sarcoidosis, histoplasmosis, cancer


Know the objective findings in vocal cord dysfunction syndrome

  • Findings in vocal cord dysfunction:
    • Adduction during inspiration (wheeze / stridor)
    • Variable extrathoracic obstruction (cords close on inspiration)


Pulm Function Testing

  • What can PFTs measure?
    • Air flow (spirometry), lung volumes, gas exchange (diffusing capacity)
    • Cannot diagnose any one disease, only determines a pattern of function.


What are functional patterns?

  • Obstructive: collapsible, narrow airways causing prolonged expiratory times
    • Asthma, emphysema, chronic bronchitis, CF, bronchiectasis
  • Restrictive: "small lungs" (2-2: fibrosis, mechanical restriction, neuromuscular dysfxn)
    • Parenchymal: idiopathic pulmonary fibrosis, pneumoconiosis, sarcoidosis
    • Restrictive bellows: nm disease (ALS, MD), chest wall abnormalities (obesity, kyphoscoliosis)
  • Gas exchange abnormalities
  • Note that both obstructive and restrictive patterns result in decreased FEV1
    • However, the FVC is decreased in restriction such that the ratio doesn't change much.
    • The FVC is normal in obstruction such that the FEV1/FVC ratio is lower.

Spirometry

  • Spirometry:
    • most reproducible value is FEV1.
    • provides the flow volume loop; always look at the flow volume curve when interpreting PFTs

Lung Volumes

  • Lung volume tests:
    • Dilution test and body plethysmography.
    • Plethysmograph uses Boyle's law (p1 x v1 = p2 x v2) in an airtight box
      • Most accurate
      • Test of choice for severe obstructive disease
    • Dilution test uses (someone's) law (c1 x v1 = c2 x v2) with a known concentration of inspired, inert gas.
      • Easier and cheaper
      • Less accurate b/c of areas of lung with "trapped gas"

Diffusing capacity

  • Gas exchange = Diffusing capacity
    • Gas exchange is a fxn of area available and capillary blood flow
    • Destroyed alveoli (emphysema) or thickening (fibrosis) will decrease the DLCO
    • DLCO = Single breath carbon monoxide test
      • Most common
      • Inhale CO, hold for 10, exhale, subtract output from input, calculate diffusion rate.
      • must be corrected for hemoglobin

Interpretation

  • Acceptibility: smooth, continuous curve; good start; good finish
  • Reproducibility: 3 maneuvers, largest FVC and FEV1 are within 200 ml of each other; see tech comments
  • Examine the loop:
    • early expiration drop-off: epiglottis closed
    • all over the place: variable effort
    • serated: coughing expiration, usable
    • Normals: FVC: > 80, FEV1: >80, TLC: >80, DLCO: 80-140, FEV1/FVC: >70
    • See workflow in slides


  • MIP, MEP: reduced in neuromuscular disease.
  • Methacholine testing: if it changes by >20% at low concentrations, asthma


  • Gems:
    • if decreased diffusing capacity is the only thing changed, think pulmonary vasculature problem
    • if elevated diffusing capacity, think asthma, pulmonary vascular congestion, or alveolar hemorrhage
    • if a bronchodilator reverses a low FVC and low FEV1 (which normally indicates restriction), think pseudorestriction


Peds Pulmonary

PE Terms

  • Wheezing:
    • Continuous musical sound
    • Expiratory in nature
    • Short inspiratory and prolonged expiratory phases
    • Usually produced by intrathoracic obstruction that worsens on expiration
    • Monophonic wheeze- obstruction by a central airway
    • Polyphonic wheeze- reflects peripheral airway obstruction
  • Stridor:
    • Musical, monophonic, often a high pitched sound
    • Inspiratory in nature
    • Usually produced by extrathoracic obstruction
      • Dynamic or fixed
    • Severe obstruction suggested by: prolongation of inspiratory phase or presence in both inspiratory and expiratory

Cases

  • Croup: seal bark, steeple sign
    • humidified oxygen, fluids, aerosolized epi, corticosteroids, heliox
    • Etiology: viral: parainfluenza, RSV, or influenza
    • cxr not usually useful
    • many develop second case


  • Pappillomatosis: just proximal to the vocal cords


  • Bronchiolitis
    • increased resp rate, wheeze, reduced oral intake, fussy
    • tx: oxygen, hydration, aerosolized meds (albuterol, epi), corticosteroids
    • get better of weeks,
    • increased lower resp infections for 1-2 years


  • Laryngomalacia
    • 3 mo old
    • noisy breathing, worse with feeding and when supine
    • no apnea or color change
    • frequent vomiting or spitting up
    • active, alert, NAD (no acute distress)
    • variable inspiratory stridor
    • no hoarseness
    • soft systolic murmur
    • cxr, bronchoscopy, sleep study, gastro-reflux eval
    • ddx: laryngomalacia, vascular ring, laryngeal / subglottic lesions
    • tx: not given
    • progx: worse for first months, improves at 6-18 mo


  • Cystic Fibrosis
    • 4 mo, 3 mo hx of cough and intermitten wheeze
    • voracious appetite, little weight gain, occasional emesis
    • 6-7 loose, malodorous stools / day
    • active, alert, thin
    • mild tachypnea
    • mild nasal crusting, clear rhinorrhea
    • few intercostal retractions, bilateral coarse polyphonic expiratory wheeze (periph obst)
    • protuberant abdomen, liver palp 3cm below rcm
    • well perfused, mild macular skin rash
    • cxr (wide mediastinum), electrolytes, sweat chloride test, fecal elastase, throat / sputum culture, dietary consultation
    • tx: dx early, resp care, nutritional supplements


Pneumonia

Concepts

  • Time of onset informs the likely causative agent:
    • 0-2 days: bacterial
    • 0-2 days: mycoplasma, viral, legionella, pneumocystis, fungal
    • chronic: anaerobic, mycobacterial, fungal, nocardia, actinomycosis


  • Distribution informs the likely causative agent:
    • Lobar: bacterial, anaerobes
    • Diffuse: viral, pneumocystis, mycoplasma, fungal
    • Nodular / cavitary: mycobacterial, fungal, anaerobes


  • Using pneumonia guidelines: decreased mortality, decreased hospital admissions, shortened stay at hospital, decreased ICU visits, reduced cost.

Details

  • Workup for the pt with pneumonia:
    • H&P
    • CBC, electrolytes, glucose, BUN / Cr, LFTs
    • ABG, puls oximetry
    • Chest radiograph
    • Sputum gram stain, sputum culture (2 days)
    • Blood culture x2 (hospitalized pts, only)
      • Legionella (DFA, urine antigen)
      • Fungi (Histo CF titers, histo urine antigen, fungal gel diffusion)
      • Mycoplasma (cold agglutinins, sputum DFA)
      • Respiratory viral titers
    • Thoracentesis


  • Criteria for admitting pneumonia pts:
    • Age > 65
    • Comorbid conditions: COPD, DM, CRI, CHF, liver disease, possible aspiration, altered mental status, post splenectomy, alcohol abuse, malnutrition, DIC, renal dysfxn
    • PE: RR > 30, sBP < 90, dBP < 60, pulse > 125, temp < 35, temp > 40
    • Labs: WBC < 4k or > 30k, pO2 < 60, pCO2 > 50, HgB < 9.0, pH < 7.35, high BUN, high creatinine
    • CXR: multilobar, cavitation, pleural effusion
    • CURB-65: confusion, BUN (> 20), RR (> 30), Blood pressure (s < 90, d < 60), 65 (age)
      • CURB-65 is scored: 0-1 is outpt, 2 is wards, 3-5 is ICU
    • "Severe" if: 1 major or 3 minor
      • Major: resp failure, septic shock (need for vasopressors)
      • Minor: rr, multilobar, confusion, BUN, WBC, platelets low, temp low, hypotension requiring fluids


  • Risk factors for penicillin-resistant penumococci infection:
    • 2 > Age > 65
    • beta-lactam therapy within last 3 mo
    • alcoholism
    • immune suppression
    • multiple medical comorbidities
    • exposure to children in day care center


  • Risk factors for enteric gram negative organisms infection:
    • nursing home
    • recent abx tx
    • multiple medical comorbidities
    • underlying cardiopulm disease


  • Risk factors for pseudomonas aerugenosa
    • structural lung disease
    • corticosteroid tx
    • abx for > 7 days
    • malnutrition / alcoholism


  • Pneumonia tx:
    • best predictor of outcome is whether appropriate abx were started upon admission (< 6 hr)
    • Specify abx as you get gram / cultures back
    • Immune competent top causes: s. pneumonia, atypicals (legionella, chlamydia, mycoplasma, h. influenzae
    • Immune compromised top causes: s. pneumonia, gram-neg bacilli, h. influenze
    • MRSA: vancomycin or linezolid
    • Switch to oral and d/c when stabilized; generally 7-10 days; add time for atypicals and even more for legionella
    • Tracheal aspirates are insensitive but have a good negative predictive value.
    • Invasive procedures to identify pathogen do not decrease mortality.


Category Description Agents Tx
I Outpt, no cardiopulm disease, no modifying factors S. pneumonaiae, m. pneumoniae, resp viruses, c. pneumoniae, h. influenzae advanced generation macrolide OR doxycycline
II Outpt, cardiopulmonary disease or modifying factors present S. pneumonaiae, m. pneumoniae, c. pneumoniae, resp viruses, enteric GNR, mixed infections (Beta lactam PLUS macrolid / doxycycline) OR fluoroquinolone
III Inpt, non-ICU S. pneumonaiae, m. pneumoniae, c. pneumoniae, H. influenzae, Legionella, Aspiration, Resp viruses, enteric GNR, mixed infections (IV beta lactam PLUS macrolide) OR IV fluoroquinolone
IVa S. pneumonaiae, Legionella, H. influenzae, aerobic GNR, S. aureus, m. pneumoniae, Resp viruses (IV beta-lactam PLUS macrolide) OR IV fluoroquinolone
IVb Risk factors for pseudomonas aerugenosa P. aerugenosa, S. pneumonaiae, Legionella, H. influenzae, aerobic GNR, S. aureus, m. pneumoniae, Resp viruses IV antipseudomonal beta lactam PLUS ( (IV ciprofloxacin / aminoglycoside PLUS IV macrolide) OR IV fluoroquinolone) )


  • Pneumonia resolution (order): fever, leukocytosis, rales, cxr (8-10 weeks!)
  • Pts that fail to respond: bronchoscopy, chest CT, open lung biopsy

Vaccination Recommendations

  • Pneumovax: >65 yo, smokers, cardiopulm disease, DM, etoh abuse, asplenia, suppressed, long term care facility; 1 time after 5 years
  • Inactivated influenza: age > 50, health care peeps, same high risk as pneumovax (plus contacts), annually
  • Attenuated influenzae: 5 < age < 49, health care peeps, NOT IN HIGH RISKERS, annually


Pulmonary Hypertension

What are the definitions of PAH?

  • Pulm HTN (PH): mPAP (mean pulmonary artery pressure) >= 25 mmHg at rest
  • Pulm Art HTN (PAH):
    • mPAP >= 25 mmHg at rest AND PCWP (pulm capillary wedge pressure = left atrial pressure) <= 15 mmHg AND PVR (pulmonary vascular resistance) >= 3 Wood units
      • note that the PCWP being <= 15 rules out left heart failure as PCWP is a measure of left atrial pressure
    • much rarer than PH
    • more severe than PH
    • more pronounced vascular remodeling
    • only type with plexiform lesions


  • PAH contains many subtypes based on etiology.
  • There are four other types of pulm HTN:
    • These four require only a mPAP >=25 mmHg
  1. due to left heart disease
  2. due to lung disease
  3. due to chronic thromboemboli
  4. unclear or multifactorial cause

Why would the pulmonary artery pressure increase?

  • Vasoconstriction, Vascular Remodeling, In-situ thrombosis
  • Dysfxn of one of three pathways that affect vasodilation / vasoconstriction: endothelin pathway, NO pathway, prostacyclin pathway
  • Pulm vascular changes include: intimal thickening, vasoconstriction, formation of plexi (PAH, only)

What are the S&S of Pulm HTN?

  • Symptoms: dyspnea, angina, syncope, edema
    • NOT associated with PH or PAH: cough, hemoptysis, wheezing, stridor
  • Syncope is a symptoms that indicates the PH / PAH is severe = Class IV.


  • Signs: loud S2, tricuspid regurg, right vent heave, S4
  • PE: jugular venous distension, ascites, hepatomegaly, lower extremity edema, cyanosis, right to left shunt


  • PH / PAH 2-2 connective tissue disorders: skin changes, alopecia, arthralgias, arthritis
  • PH / PAH 2-2 congential heart disease: murmurs, gallops, cyanosis
  • PH / PAH 2-2 portopulmonary HTN: spide naevi, telangiectasia, gynecomasita, testicular atrophy, ascies, hepatomegaly, nodular liver

Risk factors for pulmonary HTN

  • Collage vascular disease, congenital heart disease, portal HTN, HIV, drugs, toxins, pregnancy

How does one workup PH / PAH?

  • CBC: due to infection?, due to scleroderma / SLE, HIV?
  • , BMP, LFTs
  • Echo: due to left heart failure?, do to congestive heart failure?
  • V/Q scan: due to chronic PE?
    • Pulm angiogram to confirm PE
  • PFTs: due to lung disease? due to hypoxemia?
  • 6-minute walk test: how limiting is PH / PAH?
  • Right heart cathetrization: dermines the cause, grades the severity
    • RH cath gives: pressures, vascular resistance, and cardiac output can be measured
    • RH cath gives: oxygen sats in vena cava, right atrium, right ventr, and pulm artery
    • does oxygen increase from right atrium to right ventricle? -> ASD or VSD
    • is venous oxygen sat <70% -> tissue hypoperfusion
    • RH cath testing: give vasodilator; with strong (>10 mmHg to <40 mmHg) response, pt can be tx with calcium channel blockers alone


  • Classifying PH / PAH with the following factors:
    • clinical evidence of RH failure
    • Progression
    • WHO class
    • 6 minute walk distance
    • BNP
    • echocardiographic findings
    • hemodynamics

What are the treatment options for PH / PAH?

  • All pts:
    • o2,
    • diuretics,
    • digitalis,
    • avoid pulm stressors (prego / lifting / high altitude / cold medications / air travel),
    • low salt diet,
    • ligh exercise
    • immunizations
    • anticoagulate with warfarin: for pts with idiopathic, familial, anorexigenic, or thromboemboli PH


  • PH: treat underlying disease
    • Recall that all the non PAH cases of PH were "2-2 ..."


  • PAH:
    • RH cath with vasodilator challenge:
      • Positive response: just calcium blockers:
        • Diltiazem, nifedipine, amlodipine
        • Avoid verapamil
        • Tolerance occurs, monitor closely
      • Negative response: PAH specific meds
        • Prostacyclin analogs: the only drug shown to increase survival
        • Endothelin-1 receptor antagonists
        • Phosphodiesterase 5-inhibitors



Pulmonary Embolism

Obstructive Airways Diseases

  • Know the components of COPD (asthma, chronic bronchitis, emphysema) and their defining characteristics including:
    • Basic pathophysiology
    • Symptomatology
    • Diagnostic studies
    • Classifications (asthma & emphysema)
    • Treatment strategies (asthma & emphysema)
    • Factors indicating poor prognosis (emphysema)
    • Management goals (asthma)


The Pleura & Neurologic Disorders

  • Recall the anatomy and physiology of the normal pleural space
  • List the signs and symptoms of pleural effusion and pneumothorax
  • Identify pathophysiologic causes of an effusion or pneumothorax
  • Differentiate a transudative from an exudative effusion
  • Identify the characteristics of pleural fluid analysis in common pleural diseases
  • Identify the pulmonary function abnormalities associated with neuromuscular weakness
  • List those neuromuscular diseases associated with respiratory failure


Interstitial Lung Disease and SPNs

Treatment of Respiratory Failure

  • Be able to calculate the A-a gradient given an ABG and FiO2
  • Define Shunt & V/Q Mismatch (increased and decreased)
  • Know what influences the Oxygen dissociation curve to the right and left
  • Learn the types and FiO2’s of various supplemental oxygen devices
  • Understand the types and indications for Non-invasive positive pressure ventilation
  • Understand the procedure of endotracheal intubation and indications for mechanical ventilation
  • Learn basic mechanical ventilation (not covered on exam)
  • Review for the Pulmonary Exam


Pulmonary & Critical Care Case Conference

  • Introduce you to “real-world” clinical medicine through actual case studies
  • Cases not on exam
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