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    Au scu ltatory Percussion

    S im p le M e t h o d t o D e t e c t P le u r a l E f f u s io n

    JOH N R. GUARINO MD JOE C. GUARINO PhD PE

    Object ive T o assess a ne w t echn ique f o r t he de t ec t i on o f f 'r ee p l eu r a l

    fluid.

    Design

    1 1 8 c o n s e c u t i v e i n p a ti e n t s w i t h r a d i o lo g i c e v i d e n c e o f f r e e

    p l eu r a l fl u id and a con t r o l g r oup o f 175 r andom ly se l ec t ed i npa t i en t s

    w e r e e x a m i n e d o v e r a t h r e e -y e a r p e r i o d i n a p r o s p e c t i v e b l i n d s tu d y

    by auscu l t a to r y pe r cuss ion ( AP) f o r ev iden ce o f p l eu r a l e ff usion. T he

    cu to f f i n t he pe r cuss ion no te by AP is s t ri k ing ly l oud and shar p a t t he

    f lu id l eve l and a l l ows p r ec i se d e l inea t ion o f even m in imal amoun t s o f

    p l eu r a l fl u id . T he f l u id l eve l was meas u r ed in r e f e r ence t o t h e l a s t r i b .

    T he c r i t e r ion f o r de t ec t i on o f p l eu r a l e f f usion by AP was a demo n-

    s t r ab le ho r i zon ta l f l u id l eve l a t t he so und cu to f f ac r oss t he pos t e r io r

    hemi tho r ax above the l a s t r ib t ha t sh i f t ed wi th l a t e r a l t il t.

    Set t ing

    A gener a l med ica l and su r g i ca l un ive r s it y - a ff i li a t ed t each ing

    Veterans A ffairs hosp ital.

    Pa t i e n t s~ p a r t i c i p a n t s Al l inpa t i en t s w er e e l i g ib le . Ready ava i l ab i l i ty

    o f examiner s was essen t i a l . Ro ta t i ng t h i r d - and f ou r th - year med ica l

    students, reside nts, and senior staf f me mb ers par t icipated .

    In t e rv e n t i o n s None .

    Ma j o r re su l t s 113 o f t he 118 pa t i en t s wi th r ad io log ic ev iden ce o f

    p l eu r a l e f f usion had a d i s t i nc t ho r i zon ta l f l u id l eve l above the l a s t r ib

    tha t sh i f ted wi th l a t e r a l ti l t ( sens i t i v i t y = 95 .8 ) . No ne o f t he 175

    c o n t r o l p a ti e n ts e x a m i n e d a t r a n d o m s h o w e d e v i d e n c e o f p le u r a l e f-

    f us ion by AP examina t ion , wh ich was co nf i r med by ches t r ad iog r aphy

    ( spec i f i c it y = 100 ) . N ine o f t he 175 pa t i en t s wi th ou t r ad io log ic

    ev iden ce o f p l eu r a l e f f us ion had e l e va t ed d i aphr agms tha t s imu la t ed

    a f lu id l eve l i n t he exam ina t ion b y AP . E ach o f t he n ine pa t i en t s ,

    however , had no sh if t i n t he l eve l wi th l a t e r a l t il t. Subp u lmon ic e f -

    f usions w er e r ead i ly d i sp l aced and iden t i f i ed by th i s me th od o f AP .

    C o n c l u s i o n s E xamina t ion by AP i s h igh ly sens i t i ve and spec i f i c f o r

    the de t ec t i on o f f ree p l eu r a l f lu id , eve n in t he p r e senc e o f obes i t y ,

    t h i ckened p l eu r a , l ung masses , pneu monia , and assoc i a t ed l ung d i sease .

    T he exam ina t ion co r r e l a t es c lose ly wi th s t andar d and l a t e r a l decub i tus

    chest radiography. Pleural ef fusion unsuspected by convent ional means

    o f phys i ca l exam ina t ion and und e tec t ab l e by s t andar d ches t r ad iog -

    r a p h y c a n r ea d i ly b e d e t e c t e d b y t h e m e t h o d o f AP . T h e e x a m i n a t io n

    i s easy t o do and i s pa r t i cu l a rly su i t ed t o en hance de t ec t i on o f p l eu r a l

    e f fus ion . As l it t l e a s 50 mL o f f r ee p l eu r a l f l u id can be de t ec t ed .

    K e y w o rd s auscu l t a to r y pe r cuss ion ; p l eu r a l e f f us ion ; examina t ion o f

    ches t ; auscu l t a ti on o f ches t ; pe r cuss ion o f ches t .

    J GEN INTERN MED 1994;9;71 74.

    PLEUR LE FFU SIO N i s a f r e q u e n t m a n i f e s t a t i o n o f s e r i o u s

    p l e u r o p u l m o n a r y , c a r d i a c , o r e x t r a t h o r a c i c d i s e a s e a n d

    n e c e s s i t a t e s s p e c i f i c d i a g n o s is . W h e n t h e p a t i e n t i s u p -

    r i gh t , 3 0 0 t o 5 0 0 m L o f f r e e p l e u r a l f l u i d m a y c o l l e c t i n

    t h e p o s t e r i o r c o s t o p h r e n i c s u l c u s b u t r e m a i n o b s c u r e d

    b y t h e d i a p h r a g m b e f o r e i t b e c o m e s d e t e c t a b l e b y th e

    u s u a l m e a n s o f p h y s i c a l e x a m i n a t i o n a n d r o e n t g e n o -

    g r a p h i c s t u d i e s . 1 -3 T h e c o n v e n t i o n a l p h y s i c a l e x a m i -

    Rece ived f r om the Un iver s i t y o f Wa sh ing ton Schoo l o f M ed ic ine ( JRG) ,

    Seat t le , Washington, and the Veterans Affai rs Medical Center ( JRG,

    JCG ) and the D epar tm en t o f E ng ineer ing , Bo i se St a te U n iver s i t y ( JCG) ,

    Boise, Idaho.

    Addr ess co r r espondence and r ep r in t r eques t s t o Dr . Guar ino :

    M ed ica l Se r v i ce , VA M edica l C en te r , 500 W est F o r t S t r ee t, Bo i se , I D

    83702 .

    n a t io n i n c l u d i n g d u l l n e s s t o p e r c u s s io n , d i m i n i s h e d b r e a t h

    s o u n d s , v o c a l r e s o n a n c e , a n d t a c t i l e f r e m i t u s i s n o t a t

    a ll s e n s i t i v e a n d n o t s u f f i c ie n t l y s p e c i f i c f o r d e t e c t i o n o f

    p l e u r a l e f f u s io n . T h e s i g n s m a y b e i m p o s s i b l e t o d is t in -

    g u i s h f r o m p l e u r a l t h i c k e n i n g a n d u n d e r l y i n g l u n g d i s- .

    e a se . T h e y c a n b e a b s e n t i n p a t i e n t s w i t h o b e s i t y , a t h i c k

    c h e s t w a l l , o r s m a l l p l e u r a l e f fu s i o n s. A p h y s i c a l e x a m -

    i n a t i o n t h a t i s s i m p l e a n d d i s t i n c t i v e w o u l d b e o f c li n i c a l

    v a l u e .

    PRIN IPLES

    T h e m e t h o d i s b a s e d u p o n t h e p r in c i p l e s o f a u s-

    c u l t a to r y p e r c u s s i o n ( A P ) u s e d i n t h e p h y s i c a l e x a m i -

    n a t i o n o f t h e c h e s t , h e a d , a n d u r i n a r y b l a d d e r , a n d f o r

    t h e d e t e c t i o n o f a s c i te s . 4 -9 W h e n t h e p a t i e n t i s e r e c t ,

    f r e e p l e u r a l f lu i d g r a v i t a t e s t o t h e b a s e o f t h e l u n g a n d

    c r e a t e s a m a r k e d a c o u s t i c i m p e d a n c e m i s m a t c h b e t w e e n

    a i r - c o n t a i n i n g l u n g a n d t h e f lu i d i n t e r f a c e . T h e p o s t e r i o r

    c o s t o p h r e n i c s u lc u s , t h e m o s t d e p e n d e n t p a r t o f t h e

    t h o r a c i c c a v i ty , i s a d e e p , r e l a t i v e l y i n c o m p l i a n t s l it b e -

    t w e e n t h e c h e s t w a l l a n d t h e b o w o f t h e d i a p h r a g m . I n-

    v i t ro e x p e r i m e n t s p e r f o r m e d i n o u r l a b o r a t o r y w i t h in -

    f l a te d b a l l o o n s i n c o r p o r a t e d w i t h i n t r a n s p a r e n t p l a s t i c

    c o n t a i n e r s s i m i l a r in s h a p e a n d c a p a c i t y t o t h e p o s t e r i o r

    c o s t o p h r e n i c s u l c u s h a v e s h o w n t h a t m i n i m a l f l ui d v o l-

    u m e s p r o d u c e a d i s p r o p o r t i o n a t e r i s e i n t h e f l u i d l e v e l

    t h a t c a n b e p r e c i s e l y d e l i n e a t e d a n d m e a s u r e d b y t h e

    m e t h o d o f A P . I n an a n e s t h e t i z e d 3 0 - k g s h e e p s u p p o r t e d

    u p r ig h t , w e d e m o n s t r a t e d t h a t t h e i n t r o d u c t i o n o f o n l y

    2 5 m L o f p h y s i o l o g i c a l s a l i n e s o l u t i o n t h r o u g h a c h e s t

    t u b e i n t h e p l e u r a l s p a c e p r o d u c e d a h o r i z o n t a l f lu i d

    l e v e l t ha t w a s r e a d i l y d e t e c t e d b y A P . A r i s e in t h e f l u i d

    l e v e l w a s d e l i n e a t e d b y A P w i t h e a c h i n c r e m e n t o f 2 5

    m L o f t h e p h y s i o l o g i c a l s a l in e s o l u t i o n . W h e n t h e s h e e p

    w a s t i l t e d l a te r a l ly a p p r o x i m a t e l y 3 5 f r o m t h e p e r p e n -

    d i c u l a r t o w a r d t h e s i d e o f i n f u s io n , t h e f l u i d l e v e l q u i c k l y

    s h i f te d t o t h e d e p e n d e n t s i d e a n d r a is e d t h e l e v e l a l o n g

    t h e l a t e ra l b o r d e r w i t h a s i m u l t a n e o u s f al l i n t h e l e v e l

    m e d i a l l y .

    TE HNIQUE

    W i t h t h e p a t i e n t s i t t i n g o r s ta n d i n g , h i s o r h e r b a c k

    f a c i n g t h e e x a m i n e r , t h e u p p e r e d g e o f t h e t w e l f t h r ib

    i s m a r k e d o n e a c h s i d e o f t h e t h o r a x . A f t e r a p p r o x i l n a t c l y

    5 m i n u t e s u p r i g h t , f r e e p l e u r a l f l u id g r a v i t a te s t o t h e

    b a s e o f t h e l u n g . T h e d i a p h r a g m a t i c p i e c e o f t h e s t e t h -

    o s c o p e i s p l a c e d p o s t e r i o r l y w i t h i t s u p p e r e d g e a p -

    p r o x i m a t e l y 3 c m b e l o w t h e la s t r i b i n t h e m i d c l a v i c u l a r

    71

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    7 Guarino Guarino PLEURALEFFUSIONDETECTION

    P TI EN T S N D M E T H O D S

    F I GU R E 1 . M e t h o d o f a u scu l t a t o ry p ercu ss io n t o d e t e c t t h e l eve l o f

    p leura l e f fus ion a r r o w , l e f t s /d e ) a n d t o d e l in e a t e h e p a ra ve r t e b ra l r i a n g l e

    o f Gro cco a r ro w , r i g h t s i d e ) .

    line. Direct percussion is applied with the free hand

    preferably by finger flicking or with the pul p of a finger,

    along three or m ore parallel lines from the apex of each

    hemithorax perpendicularly down toward the base Fig.

    1 ). In the absence of pleural effusion, the percu ssion

    note perceived through the apposed stethoscope sounds

    dull and remains unchanged, but changes sharply to a

    loud note that is striking at the last rib, forming a hor-

    izontal baseline across the posterior hemithorax. In the

    presen ce of pleural effusion a similar sharp change to a

    loud percussion note occurs at the interface of air-con-

    taining lung and pleural fluid, approxima ting a horizontal

    line across the posterior hemithorax clearly above the

    baseline at the last rib. In the a bsence of air in the pleural

    space, the fluid level is usually highest laterally towards

    the axilla. The distance between the level and the upper

    border of the last rib is measured and used as a guide

    for thoracentesis and for estimation of fluid volume.

    Applying the same technique to the hemithorax op-

    posite the effusion, a sharp change to a loud percussion

    note clearly defines the borders of the paravertebral

    triangular area of Grocco , 1 whos e apex lies along the

    spine and who se base ex tend s 6 to 10 cm at a right angle

    to the spine Fig. 1). The triangular area can be dull to

    conventional percussion but may be difficult to define

    with this modality. It is easily and sharply delineated

    by AP.

    Over a three-year period 19 89- 199 2) , 118 con-

    secutivc inpatients with pleural effusion recognizabl e on

    chest radiographs and 175 inpatient control subjects

    selected at rand om from the medical and surgical wards,

    ranging in age from 32 to 96 years mean 64 years),

    were examined by AP. Ninety percent of the patients

    were men. The technique was developed and taught at

    the bedside by the senior investigator on patients with

    and without radiologic evi dence of pleural effusion. Pa-

    tients with pleural effusion who were teaching cases for

    trainees were not part of the study group. Finger-flicking

    percussion was done rapidly and gently at about 5-mm

    intervals along three parallel lines that ran perpendic-

    ularly from the apex of the hemit hora x to its base. Body

    contact with only the tip of the fingernail ensures pre-

    cision. The examination was usually completed within

    5 minutes and required only minimal skill. When the

    patient was maintained in the erect position with the

    fluid level at equilibrium, the endpo int of the ausco-

    percussive note was characteristically sharp, loud, and

    precise. A common, inexpensive S prague-Rappaport type

    of steth oscope was used in the examination. When the

    examiners became proficient and able to identify the

    endpoint with eyes closed and with consistent accuracy,

    they were asked to examine patients and to mark the

    cndpoint in the auscopercussive note. The marked sites

    were measured and compared by the examiners. Each

    of the 118 inpatients with pleural effusion as well as

    each of the 175 randomized con trols was evaluated by

    two to three examiners separately and independently.

    In the three-year period, 60 medical students, 15 resi-

    dents, and five senior staff memb ers wer e trained par-

    ticipants. The exam iners we re unaware of the history,

    physical, and radiologic findings prior to their evalua-

    tion. Which patients had plcural effusion was obtained

    from a central source and was known only to the senior

    investigator. There was no commun icati on between the

    examiners and the senior investigator during the ex-

    amination. All patients had a standard physical exami-

    nation and standard posterior-anterior and lateral ra-

    diography of the che st up on admission. Lateral decubi tus

    radiographs were obtained when pleural effusion was

    suspected by the radiologist after examining the stan-

    dard radiographs. Ultrasonography and computerized

    tomography of the chest wer e done for several patients

    unrelated to this study. Patients with a horizontal level

    above the last rib in the examination by AP suggestive

    of pleural effusion wer e tilted laterally with suppo rt ap-

    proximately 35 from t he perp endicular , and the ex-

    amination was repeated. Corresponding shifts in the level

    and changes in the size of the paravertebral triangle of

    Grocco in the contralateral lung base were also noted.

    To avoid false-positive examinations results, it was

    essential to mark the last rib and to keep the upper edge

    of the diaphragm atic pie ce wel l b elow this rib. False-

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    JOURNAL OF GENERAL NTERNAL MEDICINE V o l u m e 9 February) , 9 9 4 7 3

    negative results can occur when patients are examined

    too quickly upon arising from recumbency, i.e., before

    settling of the pleural fluid. Five minutes upright was

    considered sufficient time to establish a fluid level in

    nearly all patients with free pleural fluid. With the dia-

    phragmatic piece held as described below the last rib,

    the location of the diaphragm at the pe riphery at end-

    inspiration and end-expiration was easily identified by

    a sharp cutoff produc ing a suddenly loud auscopercus-

    sive note below and above the last rib, respectively.

    RESULTS

    All examiners re ported their findings independently

    to the senior investigator (JRG). One hundred thirteen

    of the 118 patients with pleural effusion accor ding to

    the standard and lateral decubitus chest radiographs had

    a demonstrable fluid level above the last rib according

    to the examinati on by AP, and a distinct shift in the level

    by lateral tilt (sensi tivit y = 95.8% ). Of note, a back war d

    tilt prod uce d a distinct rise in the fluid level; conversely,

    a forward tilt caused a fall in the level. The five patients

    who yielded false-negative findings in the initial exam-

    ination by AP had been supine approximately two hours.

    The fluid level was not discernable until the patients

    were upright for 25 to 30 minutes. The chest radiog raphs

    for each patient showed fluid loculation, and subsequent

    thoracentesis revealed viscous fluid. Each of the five

    patients were re-examined by AP at lO-minute intervals

    in the erect position. The sensitivity of the AP test for

    pleural effusion may thus increase whe n the e xaminati on

    is repeated.

    Each of eight patients in the study suspe cted to have

    subpulmonic effusion by chest radiography, confirmed

    by lateral decubitus radiography, had a distinct fluid

    level above the last rib in the examination by AP that

    shifted with lateral tilt. They were readily identified by

    the meth od of AP.

    Pleura] effusion was not specifically identified in the

    standard conventional physical examinations of the chest

    for any of the 118 patients in the admitt ing examination.

    The 175 control patients examined at random included

    patients with lung masses, pneumonia, lobectomy, dia-

    phragm elevation, and unspecified lung disease. None

    had evidence o f pleural effusion in the exami nation by

    AP or by chest radiograph.

    Nine of the control patients with unilateral dia-

    phragmatic elevation visible on the chest radiograph had

    a horizontal level above the last rib in the examination

    by AP, suggesting pleura] effusion. However, none of

    these patients had a shift in the level with lateral tilt,

    thus none constituted false-positive AP test results for

    pleura] effusion (spec ific ity = 100% ).

    The paravertebral triangle of dullness of Grocco was

    easily elicited in all patients in this study wi th unilateral

    pleura] effusion and in those patients with unilateral

    diaphragmatic elevation. A lateral tilt of 35 toward the

    side with effusion quickly obliterated the triangular area

    of dullness in the contralatera l hemithor ax, shifted the

    fluid to the dependent side, and raised the fluid level

    along the lateral border. The maneuver with a slight

    backward tilt facilitated thoracente sis of small effusions

    at the posterior axillary line. Within the triangular area

    of dullness of Grocco, breath sounds were diminished

    to absent. Muffled e-to-a changes may be elicited, and

    distant bronchovesicular breathing could be heard in

    some patients, suggesting pneumoni c consolidation. The

    abnormal findings were quickly obliterated with lateral

    tilt toward the side with pleura] effusion, with disap-

    peara nce of dullness and e-to-a changes, and return of

    normal breath sounds.

    Diaphragmatic excursions were easily and precisely

    identified at the periphery by AP and normally ranged

    from 5 to 6 cm. Of the 118 cases of pleural effusion, 57

    were due to malignant neoplasms, 32 to congestive heart

    failure, eight to pneumonia, two to empyema, five to

    acute pancreatitis, two to pancreatic abscess, three to

    ascites, two to nephrotic syndrome, two to traumatic

    rib fractures with hemothorax, one to subphrenic ab-

    scess, two to lung abscess, and two to pulmonary in-

    farctions. Pleural effusion was bilateral in 22 patients,

    18 of wh om had conge stiv e heart failure.

    For all the patients except the five who had viscous

    or loculated fluid, the examiners uniformly concurred

    100% o f the time t hat the cutoff in the percussi on note

    was striking and precise at the fluid level. When the

    patient was maintained in the erect position with the

    fluid level at equilibrium, the endpoint in the exami-

    nation of the same patient by different examiners varied

    by 0.5 cm.

    DIS USSION

    Subpulmonic effusions are common and often un-

    suspected.- They simulate an elevated diaphragm in the

    chest radiograph and can be difficult to recognize. The

    infrapulmonic fluid is quickly displaced by lateral tilt of

    the chest and readily identified by the m eth od o f AP.

    Small pleura] effusions obscured in the posterior cos-

    tophrenic sulcus or too thin to be recognized in the

    lateral decubitus radiograph can bc demonstrate d in the

    examination by AP.

    Awareness of the triangle of Grocco has clinical

    significance. The abnormal physical findings within the

    triangle have been mistaken for pneumonic consolida-

    tion in the physical examination. The mechanism of

    Grocco's triangle is unclear. T ~2 The triangular config-

    uration of dullness may be due to compression of the

    contralateral lung by the hydrostatic pressure of the

    pleura] effusion. When the patient is upright, compres-

    sion of the lun g is least at the apex whe re the hydrost atic

    pressure is low and maximal at the base where the hy-

    drostatic pressure is high. The triangular area is not vis-

    ible in the chest radiographs but is sharply delineated

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    7

    Guarino Guarino PLEUR LEFFUSIONDETECTION

    by AP. The lack of radiopaci ty in an area of what is

    thought to be compressive atelectasis is confusing. How-

    ever, i t should be noted that the radiographic factors for

    defini t ion 13 differ from the acoust ic factors i nvolv ed in

    the trans missio n of sou nd vibrat ion. 7, 14

    The me chanis m of AP involves the ef fec t on the

    passage of sound vibr at ions throu gh differe nt media. The

    transmission of sound vi brat ions depe nds up on the dif-

    ference in the acous t i c impedance values between the

    media . The acous t i c impeda nce (Z) o f a mater ia l is the

    produc t o f the sound veloci ty (c) wi th in the par t i cu lar

    mediu m and the dens i ty (p ) o f the medium:

    Z = c - o .

    T h e t r a n s m i s s i o n o f s o u n d f r o m a m a t e r i a l w i t h l o w

    a c o u s t i c i m p e d a n c e i .e . a i r o r g a s t o a m a t e r i a l w i t h

    high acoust ic impedance, i .e. , water or body fluids, is

    grea t ly inh ib it ed , permi t t ing sharp del ineat ion of the

    boundary a t the a i r - f lu id in ter face in the AP examina-

    t ion. Applicat ion of the s te thos cop e confin es and pre-

    ven t s d i spersion of sound v ibra t ions genera ted by the

    percuss ive no te and markedly enhances the prec i s ion

    of the AP examinat ion.

    In contrast to AP, the radiographi c factors are chem-

    ica l and depend upon e lec t ron dens i ty . The opaci ty o f

    the image i s p ropor t ional to the c ube of the a tomic

    num ber of the material .

    The AP examinat ion is considered a valuable sup-

    p leme nt to the convent ional ches t examinat ion to detec t

    pleural effusion. The AP examinat ion is highly sensi t ive

    and specific and corre lates close ly with the s tandard and

    lateral decubi tus chest radiographies . Small amounts of

    pleural f luid may yield posi t ive AP examinat ion resul ts

    in cases with negat ive radiologic f indings. Serial AP ex-

    aminat ions showing a change in the fluid level confirm

    the pres enc e of pleural effusion. The AP examinat ion is

    especial ly useful to alert the cl inician to the possibi l i ty

    of unsuspected p leuropulmona ry , cardiac , o r sys temic

    disease, and prompts further s tudy and fol low-up.

    The cooperation and assistance of the Medical, Surgical, and Nursing

    Services of the Boise Veterans Affairs Medical Center are gratefully

    acknowledged. The authors thank Wayne L. Kirk for his laboratory

    assistance and Barry Cusack, MD, for review of the manuscript. They

    are especially grateful to Paula Carvalho, MD, for her assistance in the

    preparation of the manuscript.

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