Chest Sonography

嘉義長庚 胸腔內科系

胸腔腫瘤科 方昱宏

Pleural effusion

Pleural space content 0.13ml/kg in adult

Pleural space

Chest echography

Chest echography

• Pneumothorax：> 15 ~ 20%• Hemothorax• Symptoms relief：– malignant pleural effusion

• Complicated parapneumonic effusion• Empyema

Indication for tube drainage

Staging and biochemistry of parapneumonic effusions

Stages Marcoscopicappearance

Pleural fluidcharacteristics

Comments

Simple parapneumonic

Clear fluid pH > 7.2LDH < 1000Glucose > 2.2 mmol/lNo organisms on culture or gram stain

Normal resolves with antibiotics alone.Drain if required on symptomatic grounds

Complicated parapneumonic

Clear fluid pH < 7.2LDH > 1000Glucose < 2.2 mmol/lMay be positive Gram stain/ culture

Requires chest tube drainage

Empyema Frank pus May be positive Gram stain/ culture

Requires chest tube drainageNo additional biochemical tests necessary on pleural fluid

• Radiographic criteria– Pleural fluid loculations– Effusion filling more than half the hemithorax– Air-fluid level

• Microbiologic criteria– Pus in the pleural space– Positive stain for microorganisms– Positive pleural fluid cultures

• Chemical criteria– Pleural fluid pH < 7.2– Pleural fluid glucose < 60 mg/dL

Murray & Nadels’, et al. Textbook of Respiratory Medicine, 5th ed., p1740equal efficacy.61 One study favoured talc over bleomycin butdid not reach significance.62 Side effects include fever, chestpain, and occasional episodes of ARDS or acute pneumonitisthat may be dose and particle size related (see below).60

A recent randomised trial of 48 patients has shown theimportance of talc particle size in the incidence of complica-tions.63 European ‘‘graded talc’’ (Novatech, Grasse, France)contains less than 50% of particles smaller than 20 mm,whereas USA and UK ‘‘mixed talc’’ contains 50% less than10 mm (Thornton and Ross, Huddersfield, UK). Mixed talcresulted in worsening gas exchange (A-a gradient change)and a much greater rise in fever and C reactive protein. Afurther randomised trial of 20 patients with ‘‘mixed talc’’showed a greater DTPA clearance than with tetracyclineconsistent with less lung inflammation.63

Of the other agents used, tetracycline is reasonablyeffective (about 65% success), cheap, and safe althoughoften now not available in the UK. Fever and pleuritic chestpain can occur with optimal doses of 1–1.5 g.59 64–66 Bleomycinis limited by its cytotoxicity and cost (£68.75 per 60 unitdose) although its efficacy is good (about 61% success).62

There are no data to support patient rotation fortetracycline class agents although in the USA many stillundertake this when using talc slurry. In tetracycline classstudies, this did not improve distribution or success rate.67 Inpractice, if good pleural apposition has been achieved and thechest radiograph confirms fluid removal then drains can beremoved within 24–48 hours.In summary, the authors recommend using calibrated talc

as the sclerosant and to consider tetracycline (if available)only for failed talc pleurodeses.

Fibrinolytics (see later for detailed discussion inpleural infection)There is a limited evidence base in the context of malignanteffusion. In three non-randomised studies in multi-loculatedmalignant effusion, radiological improvement and improveddrainage was noted with the chosen fibrinolytic (streptoki-nase or urokinase) in a significant proportion.68–70 However,the studies were uncontrolled and underpowered.A long term tunnelled indwelling pleural catheter (Pleurx,

Denver Biomaterials, Golden, CO) is a safe and effectivealternative to reduce dyspnoea, maintain quality of life, andreduce admission in recurrent malignant pleural diseasewith/without trapped lung. A retrospective review has high-lighted the safety and reductions in hospital stay (seven daysless) using such catheters with no differences in mortality ormorbidity.71 Only 8% developed malfunctioning catheters,

with pleural infection in 5%. In practice, such catheters canreduce need for re-admission with benefits to the patientallowing them to stay at home with district nurse oroutpatient management and cost savings by reduction inbed days (fig 2).Pleurectomy is invasive (10%–13% mortality) and can be

complicated by empyema, haemorrhage, and respiratoryfailure.72 VATS pleurectomy negates thoracotomy and canbe effective.73 Pleuroperitoneal shunting is no longer widelyused, probably because of its high rate of blockage (25%),infection, and tumour seeding.74

PLEURAL INFECTIONPleural infection (first described in 500BC) was treated byopen drainage until the 19th century changing to closeddrainage after 1919.75 Currently, in the UK, up to 40% ofempyema patients require surgery because of failed tubedrainage and 20% still die.

PathogenesisParapneumonic effusions occur in up to 57% of casesalthough primary empyema can occur de novo withoutpneumonia.76 Empyema development is a progressive processfrom a simple exudate (‘‘simple parapneumonic effusion’’),to a fibrinopurulent stage (‘‘complicated parapneumoniceffusion’’ before frank pus or ‘‘empyema’’ develops) thenfinally an organising stage with scar tissue (see table 2).In the ‘‘simple’’ stage increased capillary vascular perme-

ability and proinflammatory cytokine production occurs.77

The non-viscous exudate has a low white cell count andlactate dehydrogenase (LDH) level, normal pH and glucoselevels, and no bacteria. Antibiotic treatment alone here maysuffice.76 Increasing fluid and bacterial invasion accelerateneutrophil migration and coagulation cascade activationleading to fibrinous loculations. Neutrophil phagocytosisand bacterial death amplify the inflammatory process withincreased lactic acid production, glucose metabolism, and arise in LDH levels, with a fall in pH, leading to afibrinopurulent collection (pH,7.20, glucose ,2.2 mmol/land LDH .1000 IU/l).77 Fibroblast proliferation leads to apleural peel restricting lung function and re-expansionleaving a persistent pleural space with infection risk.

MicrobiologyThe microbiology of community acquired pleural infection isdifferent to that of hospital acquired (see fig 3). Overallcurrently, aerobes (especially Gram positive) are the mostabundant particularly Streptococci milleri and Staphylococcusaureus.78 S aureus often occurs in traumatic, nosocomial,immunocompromised, or postoperative settings.79 Gramnegative aerobes (Escherichia coli, Pseudomonas spp,Haemophilus influenzae, and Klebsiella spp) also occur usuallyin mixed growths. Anaerobes are on the increase (12%–34%of positive fluid culture, 14% alone without aerobes)presenting insidiously, with less fever, greater weight loss,often after aspiration pneumonia or with poor dentalhygiene.78

Diagnosis and stagingThe presence of chest radiological infiltrates and pleural fluidmay suggest pleural infection. Empyema should be suspectedafter failure to respond to appropriate antibiotics. Lateralchest radiograph may show pleural fluid not visible on the PAchest radiograph.76 Ultrasound enables exact location of anyfluid collection and permits thoracocentesis.17

Ultrasound and computed tomographic appearances do notcorrelate with the biochemical staging of pleural infection,but pleural thickness on contrast enhanced computedtomography can correlate with purulence.80 Contrastenhanced computed tomography may help differentiate

Figure 4 Contrast enhanced computed tomography showing multi-loculated empyema with ‘‘split pleura sign’’ (enhanced pleural tissuenoted on both parietal and visceral surfaces).

706 Medford, Maskell

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Indication for tube drainage

Pneumothorax

單向閥效應氣體累積

肋膜腔壓力增加

壓迫右心減少回心血流

血壓降低 休克致死

Tension pneumothorax

Complication

ëPneumo-mediastinum (縱隔腔氣腫)ëSub-cutaneous emphysema (皮下氣腫)

ë

ë

評估嚴重程度

脊椎

Ａ

Ｂ

肺門

氣胸區域1- (B3/A3)>50%

A-B>2cm

Pleural Sliding Sign

Comet Tail Artifacts

• Image

Normal Pneumothorax

Diaphragmatic Ultrasound

Right side diaphragm excursive

Left side diaphragm excursive

Diaphragm Thickness Fraction (TF%)

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