The opening into the pleural cavity may be direct or oblique: if
direct, it remains open; if oblique, it is generally more or less
valvular. The symptoms, prognosis, and treatment vary accordingly.
Through a patent orifice the air enters in inspiration, and goes out
with the expired air from the lungs. As it cannot accumulate, there can
be no positive air-pressure within the pleura. If, however, the orifice
be valvular, although the air enters it does not escape, for it presses
upon the valve and closes it. If the valvular fold be perfect, the air
soon becomes excessive in quantity, and exerts dangerous pressure upon
the lung and adjacent organs. By means of a trocar, attached by tubing
to a water-pressure gauge, Douglass Powell[242] ascertained post-mortem
the degree of intra-pleural pressure present in 16 cases of
pneumothorax. In 4 out of these cases the pressure was nil. In 12 there
was more or less intra-pleural pressure present, varying in degree from
1¾ to 7 inches of water.
[Footnote 242: _Medico-Chir. Trans._, 1876.]
Unless the lung be mechanically prevented, the entrance of air into the
pleural cavity at once produces a retraction of the lung, owing to its
elasticity. There is no compression of the lung unless the air is
increased in quantity by each inspiration, and, having no exit,
accumulates; then the lung may be forced against the spinal column and
the residual air actually {577} forced out of the alveoli. Powell[243]
questions whether the intra-thoracic pressure excited in pneumothorax
is ever equal to what is sometimes the case in pleurisy: the highest he
had ever met with in pneumothorax was 7 inches of water. Garland,[244]
in repeating Damoiseau's experiments in testing the effects of the
introduction of air into the pleural cavity, found that the air did not
penetrate between the lung and the lateral chest-walls until the lower
border of the lung had retracted upward the distance of several ribs.
[Footnote 243: _Loc. cit._]
[Footnote 244: _Loc. cit._]
One of the most pronounced effects constantly observed in pneumothorax
is the immediate displacement of the heart to a greater extent than in
pleurisy. Gaidy,[245] as far back as 1828, described displacement of
the heart as an important sign of pneumothorax. He related a case
where, at the moment of the perforation, the woman was conscious of the
heart's beat having been transferred to the right of the sternum.
Powell[246] out of 17 cases found the heart displaced in 16: in the
seventeenth the unruptured lung was so consolidated that it could not
collapse. In pneumothorax of the right side a careful examination is
sometimes required to detect the displacement of the heart. The apex
can be discovered at a considerable distance to the left of the nipple,
with the right ventricle drawn to the left edge of the sternum. It has
been generally believed that the cause of this displacement was the
intra-pleural pressure of the air, but this does not satisfactorily
explain it, for there can be no pressure until the elasticity of the
lung has been overcome. In 13 of Powell's cases there was great
displacement of the heart with different degrees of intra-pleural
pressure. In 3 cases there was great displacement of the heart with no
intra-pleural pressure. The same author[247] showed, experimentally,
that the elastic tension of one lung, when unopposed by that of the
other, was sufficient to draw aside the mediastinum, and with it the
heart. He thus demonstrated that these displacements are by no means
necessarily a sign of intra-pleural pressure, since they may occur to
the right of the sternum without there being any pressure. Clinically,
we know that the admission of air into the pleural cavity immediately
and constantly displaces the heart, unless the opposite lung be
consolidated or otherwise injured in its resiliency. This occurs even
when the patent orifice of the perforation prevents the accumulation of
any quantity of air. There is not enough air to produce direct
pressure, but there is enough to impair the elastic traction of the
lung, and thus to destroy the equilibrium of traction which keeps the
heart in its normal position. The healthy lung by its unimpaired
tractile force immediately draws over the heart. Skoda[248] maintains
that "air does not enter the pleural cavity simply at the cost of the
torn and retracted lung, but the sound lung also retracts to such a
degree as to move the mediastinum." Garland's experiments[249]
conclusively demonstrate that the air in pneumothorax is powerless to
exert an appreciable lateral displacing force until the lung has
completely collapsed; and this does not ordinarily occur. There can be,
he says, but one cause of constant and early displacement of the
heart--the elastic force of the opposing lung, which draws it over to
itself. He adds that "the explanation of the greater displacement of
the heart in pneumothorax is that the air, having practically no
weight, cannot exert upon the heart the negative pressure which an
effusion evidently would."
[Footnote 245: _Arch. Gén. de Méd._, tome xvii., 1828.]
[Footnote 246: _Medico-Chirurg. Trans._, vol. lix.]
[Footnote 247: _British Med. Journal_ and _Med. Times and Gazette_,
July, 1869.]
[Footnote 248: _Auscultation and Percussion_, Eng. trans.]
[Footnote 249: _Loc. cit._]
The fluid in hydro-pneumothorax is very rarely of a serous character.
Saussier found but 1 such example in 169 cases. It is almost always
purulent pneumothorax, and frequently it has a very offensive fetid
odor from putrid decomposition. Mixed with pus there are sometimes
found masses of {578} pseudo-membranes, débris of lung, and gangrenous
patches, as in purulent pleurisies. The fistulous orifice through which
the air has entered is not always easily found, being often hid away
among false membranes. It is small and tortuous, and can only be
discovered by placing the lung under water and blowing air through the
bronchial tubes. Sometimes the orifices close and the air becomes
encysted, interlobular, or diaphragmatic. There is sometimes only one
opening; again, there may be several. Nolais reports a case where there
were six openings. Orifices with lacerated edges are met with, varying
in length from one to ten or twelve centimeters. It must be borne in
mind that perforation can take place without producing pneumothorax.
Saussier found this occurred in 2 out of 74 cases, and in 8 out of 29
resulting from pleurisy. Fériol and Guéneau de Mussey give similar
cases.
SYMPTOMS.--The initiatory symptoms of pneumothorax vary according to
the cause which produces it. When the effusion of air into the pleural
cavity is from perforation of a diseased lung (most frequently
tuberculous, more rarely gangrenous or from an abscess), the first
symptom is a sudden agonizing pain in the side, accompanied with
dyspnoea amounting almost to suffocation. In rare instances, where
strong old adhesions limit the pneumothorax, there may be only slight
pain, without dyspnoea. The rush of a moderate quantity of air into the
cavity causes the lung to collapse; but should the amount of air be
excessive, it will render the symptoms of oppression most intense, for
it will compress the lung and heart and obstruct the capillary
circulation in the lung. Such must be the case, for there is no
aspiration of blood from the large veins, and no aëration of blood in
the lung. The patient often feels as if the chest were being torn away,
and the expression of his countenance betrays distress and alarm. If
the orifice be large and valvular, preventing the escape of the air,
the air accumulates rapidly and completely forces the air out of the
lungs, and death shortly follows, sometimes in a few hours. There is no
rise of temperature or fever. On the contrary, the temperature very
frequently falls one or two degrees below the normal in consequence of
the sudden collapse, the pulse from exhaustion being very frequent and
feeble, accompanied by cold sweats. The voice becomes exceedingly
feeble and whispering. In many cases the patient does not sink at once
from the shock of the perforation, but becomes less oppressed, although
he suffers considerably, being unable to lie flat in his bed.
Respiration is not only frequent (sometimes 60 per minute), but the
dyspnoea is oppressive and distressing to witness. Fever follows
invariably, and sometimes with great rapidity, caused by pleuritis.
When this occurs, the patient again suffers from dyspnoea as the
purulent fluid accumulates in the pleura and gradually dropsy comes on.
These cause dyspnoea and cyanosis. The position of the patient, leaning
forward, supporting his elbows on his knees, indicates his agony and
difficulty in breathing; the pain appears to go through and produce
local hyperæsthesia, and the patient dies from the empyema with hectic
and oedema of the lungs. The pleurisy excited may be simply serous in
its products, even when it is tuberculous in origin. Usually, however,
it is purulent, and we must then expect to find the grave symptoms we
have enumerated in speaking of empyema with hectic and septicæmia.
PHYSICAL SIGNS.--These are well distinguished and marked, and lead
easily to its diagnosis. Inspection shows the side to be immovable and
the dilatation permanent; the spaces between the ribs are obliterated
and the shoulder raised. There is no rhythmical expansion and
contraction of the walls of the chest, the diaphragm is not elevated,
and the liver and stomach are kept down. Air continues to enter the
cavity, until the quantity is so great that its tension is equal to the
atmospheric pressure. The contrast between this condition and that of
the healthy side is very great. In the former the breathing is labored,
with painful muscular contraction in the walls and whole side. {579}
Percussion over the chest gives a hyper-resonant sound, with a
graver-pitched tympanitic resonance. There is but little sense of
resistance to the finger, owing to the elasticity of the contained air.
When fluid is secreted in the second stage we have absolute flatness at
the base over a horizontal level, and tympanitic resonance above. The
pitch of this last sound varies according to the tension of the gas
contained in the chest and the correlative tension of the thoracic
walls. If this tension be feeble, the pitch is higher; if it be
extreme, the tone will be drum-like, muffled, acute, and the tympanitic
character will be less easily perceptible. It may happen that the pitch
will be so high that we may be misled and think there is flatness. It
is not true flatness, but a clean and high-pitched sound, very
different from the tympanitic sound usually found; it is sometimes
remarkably metallic in character. With auscultatory percussion, using a
solid pleximeter, we have the prolonged metallic resonance which
Trousseau appropriately named the bruit d'airain.
The area of hyper-resonance and flatness on percussion is changed with
the altered position of the patient. The fluid, obeying the law of
gravitation, takes its hydrostatic level, and when the patient's chest
is upright is horizontal. Hyper-resonance is often pronounced over the
sternum, and sometimes infringes upon the healthy side. When the
disease is on the left side it obliterates the normal dulness over the
cardiac area.
Palpation.--Thoracic vibrations of the voice are not felt over the
portion of the chest containing air, nor over that containing fluid.
This absence of vocal fremitus is very characteristic. The hand detects
that the heart has been displaced toward the sound side and that the
abdominal viscera are pushed down.
Auscultation.--The auscultatory phenomena vary according to the cause
of the pneumothorax and the size and direction of the orifice. In
tubercular cases, where perforation has produced a large, free opening,
as the air passes in and out of this large pleural cavity with firm
walls (the lung having collapsed perhaps to one-third or less of its
normal size), we have the physical conditions which give marked
amphoric and metallic respiratory sounds, with absence of respiratory
murmur. The amphoric breathing is of greatest intensity near the point
of perforation, which ordinarily is at the mammary or upper scapular
region, and is found in both inspiration and expiration. The cough and
the whispered voice give the characteristic metallic quality. There is
also metallic tinkling produced by droppings of fluid in the cavity, by
the shaking of the body, or by vocalization. Even when the orifice in
the lung is closed we may have amphoric echo, from sounds produced in
the bronchi, and passing through a cavity filled with air. The
intensity of these sounds varies in different cases. Sometimes they are
very loud; in other cases they are feeble and seem distant from the
ear. The fine metallic tinkling may be heard at one moment and
disappear at the next. These amphoric and metallic sounds, heard at
different points, are characteristic of pneumothorax with free
openings. When, however, the orifice from tubercular perforation is
small, oblique, or valvular, the respiratory murmur is inaudible,
except perhaps at the very apex of the lung, and we cannot perceive any
adventitious auscultatory phenomena beyond a faint, distant, hollow
sound.
There is, in both kinds of orifices, the well-known splashing
Hippocratian succussion sound on shaking the chest. The latter is
pathognomonic of hydro-pneumothorax, and is sometimes heard when no
other sign is present. The hands applied over the surface of the chest
feel the fluctuations of the fluid striking against the interior walls.
When pneumothorax follows purulent pleurisy we do not find immediately
the pronounced symptoms nor the physical phenomena heretofore described
as occurring when it is produced by rupture from the lung into the
pleural cavity. The condition {580} of the parts is very different. Pus
is present in considerable quantity in the cavity, and the ulceration
of the costal pleura and the soft walls of the chest allows the fluid
to flow outward and air to enter the cavity. Or there may be necrosis
of parietal pleura into a bronchus and consequent discharge of pus
through the mouth. The lung is already disabled. The violent pain in
the side and the dyspnoea are no longer found. Indeed, the exact time
of the rupture and commencement of the discharge is frequently unknown
to the patient himself. The symptoms of entrance of air into the
pleural cavity may not occur for some time. The patient who has had
empyema is made more uncomfortable; the discharge through the mouth is
offensive, and its quantity and its character call attention to the
chest, in which percussion shows the presence of air; auscultation
gives amphoric breathing, and succussion demonstrates the presence of
air and fluid in the pleural cavity. Very soon, however, the presence
of air produces putridity of the secretion, with loss of appetite,
fever, diarrhoea, and the other alarming symptoms of pyo-pneumothorax.
In some instances the pleura discharges its contents and heals over.
There is another variety of pneumothorax, which is ordinarily attended
with only temporary inconvenience, and which may soon disappear,
leaving the patient no worse than before the attack. This variety of
pyo-pneumothorax may be produced by the sudden rupture of emphysematous
vesicles, by coughing, or even without any unusual force in the
expiratory effort, the alveoli having become extremely thin and brittle
by degeneration of their walls. For the minute the pain is violent and
the dyspnoea great, but it soon subsides, and in a few days the gas may
be all absorbed, unless it is in large quantity. If the pleura is
healthy and the lung not otherwise diseased, the rupture may not cause
any inflammatory action, fever, or effusion. The rupture may heal over
entirely, or if some inflammatory effusion is produced it will probably
be rapidly absorbed. In exceptional cases pleurisy may be excited and
the case become prolonged. While the air remains in the pleura we have
the physical signs characteristic of pneumothorax--displaced heart, as
shown by palpation and auscultation, tympanitic percussion resonance,
amphoric breathing, and succussion.
DIAGNOSIS.--Ordinarily, there should be no difficulty in diagnosing
pneumothorax, no matter how it is produced. We have simply to consider
well the already-mentioned modes of the commencement of the disease,
and give due value to the characteristic physical signs, especially
displacement of the heart, hyper-resonance on percussion, absence of
vocal fremitus, amphoric respiration, succussion, and decided shifting
of flatness and resonance on change of position. When all these signs
are present, each being in itself almost characteristic, there can be
but little question. Obstruction of a large bronchus would be followed
by absence of health sounds and intense dyspnoea, but we should not
have the other physical signs of pneumothorax. Extensive emphysema
would produce some of the signs--exaggerated resonance on percussion
and enlargement of the side. Emphysema, however, is bilateral, and the
resonance over an emphysematous lung has not the same pronounced
tympanitic quality as in pneumothorax. The enlargement in emphysema is
more under the clavicle; the breathing not amphoric; the normal murmur,
although enfeebled, is never completely annulled; and the heart is not
displaced. Large superficial pulmonary cavities with firm but thin
walls give us several of the physical signs of localized pneumothorax,
such as amphoric respiration and metallic tinkling; but the succussion
sound is never heard over them. The tympanitic percussion is rarely so
pronounced in a cavity as in pneumothorax, and in the latter there is
never the cracked-jar sound. In phthisical cavities of large size there
probably would be depression instead of enlargement of the chest. The
situation will ordinarily enable us to make the differential diagnosis,
for localized pneumothorax is almost always low {581} down in the
thorax, and the pulmonary cavities but rarely below its middle third.
The progress of the case and clinical history would clear up the
diagnosis. If a circumscribed pneumothorax was present with phthisis,
the diagnosis might be difficult. Powell calls attention to the
similarity of some of the signs of acute congestion rapidly supervening
at the base of a comparatively sound lung to those of pneumothorax. But
in the former the resonance, although high-pitched, is not truly
tympanitic, and the heart is not displaced. There is no other disease
of the chest where we find in such close proximity the two extremes of
percussion sounds--flatness from the secondary effused fluid, and the
tympanitic resonance above. If delicate, slight percussion is used, the
line of demarcation can be clearly defined; if, however, the force of
the percussion stroke be even of moderate intensity, the flatness is
mingled with the tympanitic quality, as it is in percussing from the
left lobe of the liver to the stomach.
PROGNOSIS.--The prognosis is unfavorable and always uncertain. During
the first few days after the rupture of the pleura it is especially
bad, though it becomes less so as time goes by. There are cases where
the perforation and its results appear to prolong life. "If the
opposite lung be healthy, we may hope that arrest of the pulmonary
disease may convert the case into one of chronic empyema" (Powell).
But, unfortunately, the rupture often occurs when the patient is
emaciated and dying of chronic lung ulceration. Cases of
pyo-pneumothorax produced in advanced phthisis or by gangrene of the
lung are almost invariably fatal. The most unpromising cases at first
sometimes prove the least serious, and, again, those that appear at the
commencement slight, contrary to expectation, die. Much depends upon
the condition of the other lung and the position of the perforation. If
the other lung be healthy and the perforation low down, the chances of
recovery are better. The progress is most favorable in the cases where
the rupture occurs from emphysema. When from purulent pleurisy the
discharge passes through a bronchus, the orifice may heal and in due
time plastic material be thrown over it, and the air and fluid be left
in the pleura. Cases are reported where the orifice remains open and
pneumothorax lasts for a long time. Laennec reported one case where the
patient lived six years. Fuller[250] reports another where the orifice
was open at the end of eleven months, another nineteen months, and
another twenty-seven months. We have mentioned Demarquay and Marotte's
experiments of the innocuousness of air injected into the pleura. Air
is harmless, as they have shown, in the pleura, unless sulphuretted
hydrogen or sulphite of ammonia be developed. Fuller says the prognosis
is very unfavorable when the effusion is large, with great displacement
of the organs. Flint considers pneumothorax occurring as a complication
of phthisis as almost hopeless. It is important to ascertain promptly
the nature and direction of the opening, whether it be free or
valvular.
[Footnote 250: _Diseases of Chest._]
TREATMENT.--This is in a great measure palliative. Hypodermics of
morphia or opiates relieve the agony and lessen the shock caused by the
perforation. Alcoholic and diffusible stimulants may sustain the heart
in its struggle against the effects of dislocation and impaired
circulation. Care must be taken not to depress the powers of reaction
by too much morphia. Hot water in india-rubber bags applied to the
chest gives great relief. Alcoholic stimulants must be given to prevent
sinking from exhaustion. When the distension from air is excessive,
paracentesis gives marked relief, the lives of patients having been
prolonged for days by it. If the opening is valvular, to prevent the
air from accumulating in excessive quantity Reybard's protected
gold-beater's skin trocar may be used and kept in the chest. Otherwise
fine aspirators may be employed, which would seem to be harmless, and
the {582} operation be repeated whenever necessary. Larger points and
the trocar should never be used, as there is danger of making a
permanent fistulous orifice, as well as of injuring some blood-vessels
or the lung itself. After the excess of air has been removed by
aspiration the affected side should be strapped to control the
inspiratory movements on renewal of positive pressure. Anstie[251]
recommends drachm ss doses of ether every three or four hours.
Fernet[252] recommends inhalation of oxygen. If fluid should compress
the chest, some of it must be removed by aspiration, but care must be
exercised, for the presence of fluid is conservative in its effects.
Its pressure stops up the orifice and promotes its healing. If it
becomes fetid, pleurotomy, with detersive washes, ought to be resorted
to. Food should be frequently administered, with quinine and cod-liver
oil, and good hygienic surroundings prescribed.
[Footnote 251: _Reynolds's System of Medicine_, vol. iv.]
[Footnote 252: _Nouveau Dict. Méd._, vol. xxviii.]
Hæmothorax.
DEFINITION.--Accumulation of blood in the thoracic cavity unconnected
with inflammation of the pleuræ.