Posttraumatic Empyema

Posttraumatic Empyema Kit V. Arom, M.D., Frederick L. Grover, M.D., J. David Richardson, M.D., and J. Kent Trinkle, M.D.

ABSTRACT This is a report of the experience gained was involved in 16 patients, and bilateral infrom treating 18 patients with posttraumatic em- juries occurred in 2 patients. Fifteen patients had major chest injuries, pyema during a 36-month period. The objectives of treatment were twofold: complete reexpansion of the and 9 had no trauma to other organ systems. lung, and evacuation of infected foreign material Three had chest wall contusion or skin lacerafrom the pleural space. The techniques of achieving tion. Eight patients had concomitant abdominal these objectives were tube thoracostomy initially, injuries, and 5 of these developed a subphrenic abscess. Thoracic and extremity injuries were followed by early thoracotomy if necessary.

The distinction between posttraumatic empyema (hemothoracic empyema) and infected organizing hemothorax (infected hemothorax) is often subtle and difficult to determine. The former term is generally used in cases in which gross pus is aspirated from the pleural space and the infection has been present for a longer period of time. Traumatic ernpyema in this communication includes only patients with a positive culture of the pleural peel or gross purulent drainage prior to operation. The larger group of patients with simple clotted hemothorax is not included in this series. Clinical Material and Results During a recent three-year period, 18 patients with posttraumatic empyema were treated at the Bexar County Hospital. During the same period, approximately 300 patients with thoracic trauma had been admitted to the cardiothoracic surgery service. Clotted hemothorax occurred in approximately 15%, and an empyema developed in 6%--the 18 patients in this study. Their ages varied from 15 to 69 years, and there were 17 men and 1 woman. The mechanisms of injury included 9 gunshot wounds, 6 stab wounds, and 3 automobile accidents. A single pleural cavity From the Division of Cardiothoracic Surgery, The University of Texas Health Science Center at San Antonio, and The Audie Murphy Veterans Administration Hospital, San Antonio, TX. Accepted for publication Aug 25, 1976. Address reprint requests to Dr. Arom, Division of Cardiothoracic Surgery, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78284.

254

present in 4 patients. Three patients developed empyema without a major chest injury. Large chest tubes (36 or 38F) were inserted immediately in the emergency room when a diagnosis of hemothorax was confirmed by chest roentgenogram. Seventeen tube thoracostomies were performed in 15 patients (2 received bilateral tubes). Eleven of the 15 required a second tube because of inadequate drainage. Seventeen patients subsequently underwent thoracotomy and decortication. Early decortication was used when there was persistent fever, malaise, and elevated white blood cell count along with residual hemothorax or decrease in lung volume or both. Decortication was performed an average of 16 days following injury. This was later than decortication in the group with clotted hemothorax alone; their general condition allowed decortication to be performed sooner if necessary, usually within the first week following injury. The 18 patients were divided into three groups for analysis: Group 1, 9 patients with chest injury alone; Group 2, 6 patients with chest and associated injuries; and Group 3, 3 patients with mild chest injury and major abdominal trauma. The average age, sex, temperature, and white blood cell count of each group are summarized in Table 1. Six of the 9 patients in Group 1had a pure staphylococcal infection, Group 2 had mixed infections, and all 3 patients in Group 3 had bacteroides infection. Other bacteria found were Streptococcus, Diplococcus, Pseudomonas, and Klebsiella species and Escherichia coli. Antibiotics were used according to the indications of sensitivity cultures. Operative

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Arom et al: Posttraumatic Empyema

methylprednisolone; and vigorous pulmonary toilet [211. Decortication was carried out through a low posterolateral thoracotomy incision, usually with rib resection. A combination of orAge Temp WBC ganized clot and fibrinous, purulent peel was Group Sex (yr) ("c) (cell/mm3) found in every patient. The gelatinous material was extracted manually, and the peel encap1 All male 30.3 38.9 14,400 sulating the lung was removed. This was usually 2 5 male, 28.8 39.2 25,100 technically simple in patients with early em1 female 3 All male 20.6 39.4 22,000 pyema, in whom a plane of cleavage could be developed between the visceral pleura and the Group 1 = thoracic injury alone; Group 2 = thoracic and peel. Entrance into the pleural space and deabdominal injuries; Group 3 = minor thoracic and major velopment of the peel is best started anteriorly, abdominal injuries. since the bulk of the peel presents posteriorly. Pulmonary resection was not necessary in any pleural fluid cultures had no growth in 6 of 17 patient. Two large chest tubes were inserted at patients, but cultures of the peel were all posi- operation. Particular care was given to total removal of the visceral peel to allow complete tive for pathogens. Anteroposterior chest roentgenograms usu- reexpansion of all lobes. Appropriate antibiotics ally showed the pleural peel and partially col- were given for five to seven days. All chest tubes lapsed lung (Fig 1).Lateral views frequently did were removed within five days except in 2 panot demonstrate either the posterior triangle- tients with a persistent air leak. There were no shaped shadow described in hemothorax or the recurrences of empyema, and postoperative posterior inverted D seen in postpneumonic chest roentgenograms (Fig 2) showed complete reexpansion of the lung. empyema [lo]. Initially all patients received the same treatThe hospital courses of the three groups were ment for pulmonary contusion: fluid restriction; quite similar (Table 2). Two patients in Group 1 administration of diuretics, albumin, and had chest tubes removed and were discharged Table 1. S e x , A v e r a g e A g e , Temperature, arrd W h i t e Blood C o u n t in 18 Patients with Posttraumatic E m p y e m a

Fig 1 . Anteroposterior view of the chest one week after injury and before decortication shows a pleural peel and decreased left lung volume.

Fig 2. After decortication an anteroposterior chest roentgenogram of the same patient as in Figure 1 shows that the left lung is completely expanded, with no residual pleural peel.

256 The Annals of Thoracic Surgery Vol 23 No 3 March 1977

Table 2 . Summary of Clinical Course in 18 Patients with Posttraumatic Empyema

Table 3. Results of Decortication in 18 Patients with Posttraumatic Empyema

Group

Group

Averaged Data

1

2

3

Results

Days of intubation Days lapsed before

10.5 16.3a

12 12

14 20

Complications

decortication Days hospitalized after

8.8

25.2

30

decortication aTwo patients were readmitted for decortication.

Air leak

Wound infection Cardiac arrest

(mechanical) Death

1

2

3

2

...

...

... ...

...

1 1

...

...

...

1

Group 1 = thoracic injury alone; Group 2 = thoracic and abdominal injuries; Group 3 = minor thoracic and major abdominal injuries.

Group 1 = thoracic injury alone; Group 2 = thoracic and abdominal injuries; Group 3 = minor thoracic and major abdominal injuries.

with only a small pleural reaction at the costophrenic angles. These 2 patients subsequently returned with sepsis and purulent material in the pleural cavity that required delayed decortication during a second hospitalization. In Group 3, empyema probably developed following a subphrenic abscess. The pleural fluid was aspirated with a needle before chest tubes were inserted. The main organisms in this group were bacteroides, suggesting that the empyema may have developed secondary to the abdominal sepsis rather than from an infected hemothorax. One patient in this group, who was seriously ill and did not undergo decortication, died from intraabdominal complications. The postoperative hospitalization was approximately nine days in Group 1. Groups 2 and 3 had a longer average hospitalization due to associated injuries. There were 4 postoperative complications and 1 nonpulmonary death among the 18 patients (Table 3). Two patients in Group 1 had a continuous, minimal air leak and required chest tubes for nine and ten days, respectively. One patient in Group 2 had a minor wound infection, and during induction of anesthesia another experienced a brief cardiac arrest from which he recovered. One patient in Group 3 died.

survives. But if it be mixed with blood, muddy and foul-smelling, he will die.” His initial treatment included intercostal incision or rib resection, packing the wound with cloth, and covering the opening with cotton to establish closed drainage-providing the basis of therapeutics until twentieth century [26]. Operation for removal of the empyema peel was performed by Fowler [8]in 1893 in a previously drained empyema, but the term decortication was not used until Delorme introduced it in 1896 [61. In 1915 Lilienthal [121 described thoracotomy with lung mobilization, which was the first attempt to treat empyema by decortication. The difference between infected hematoma and purulent pleural infection was not recognized until 1900. Delorme [71 in 1912 stated that posttraumatic empyema was favorable for decortication. Spencer [20] in 1915 and Battle [l] in 1917 recognized the pathophysiology of pulmonary compression in posttraumatic empyema and favored early decortication. Turner [23] in 1919 described empyema following hemothorax as more serious than ordinary empyema, with drastic measures demanded for its cure: “The pathology is essentially different, for here [infected hemothorax] we are dealing with a serous sac filled with masses of blood clots which have become infected and are slowly disintegrating” [23]. Moynihan [13] in 1920was cognizant of the importance of freeing the lung from constricting adhesions (organizing hemothorax) when thoracotomy was performed for removal of mis-

Comment Nearly 2,400 years ago thoracic empyema was recognized by Hippocrates. He wrote, “When empyemata are opened by the cautery or by the knife and pus flows pure and white, the patient

257 Arom et a]: Posttraumatic Empyema

siles, and he thought that on many occasions liberation of the lung was the most important indication for operation. The differentiation between posttraumatic empyema and postpneumonic empyema was also lacking during World War II. In 1944 Churchill (personal communication, Samson and Burford [16]) suggested that the lack of differentiation might have been due to the great number of influenza1 empyemas, which largely overshadowed the posttraumatic cases in number and interest and caused considerable chronicity and death. The contributions of Burford and Samson [3, 15,171 in the early 1940s ushered in the modern treatment of posttraumatic empyema. In March of 1944 they reported successful primary decortication for hemothoracic empyema, and their study of the pathogenesis of hematoma organization clarified the therapeutic approach. PATHOLOGY

OF

HEMATOMA

ORGANIZATION.

The process of hematoma organization begins with the deposition of a thin film of fibrin and blood cells over both pleural surfaces. This loosely adherent clot is followed by early angioblastic and fibroblastic proliferation, which extends into the clot from the pleura. The hemothorax thus becomes a closed hematoma of the pleural space, the wall of the envelope being composed of an ever-thickening layer of fibroblasts. The pleura itself does not become thickened but remains a thin, translucent membrane. Proof of the normalcy of the pleura is found in microscopical sections of peel stained for elastic tissue: none has been discovered in the peel. However, in sections of lung or thoracic wall, elastic fibers always are found just beneath the pleural mesothelium. Within three or four weeks the outer, older aspect of the peel (next to the pleural surface) becomes adult fibrous tissue, with collagen fibers and nuclei arranged parallel to the surface. The long axis of the capillaries remains at a right angle to the surface and continues through the pleura. Within seven weeks, small arterioles with smooth muscle fibers in their walls can be demonstrated at or near the outer aspect of the peel. Along the inner or younger surface of the peel, active fibroplasia continues, resulting in progressive thickening. The mature peel forms a

tough, inelastic membrane, 1 cm or more in thickness, which invests the visceral pleura and prevents pulmonary reexpansion. The segment of the envelope overlying the parietal pleura is thicker, more adherent, and more vascular than the visceral segment. Usually the fibrosis increases, and tufts of scar tissue extend through the pleura into the interstitial tissue of the lung. Cellular intimacy develops between the pleura and peel so that a cleavage plane is difficult or impossible to establish, and the invaded lung becomes poorly expansile. Calcium may be deposited in the peel within three or four weeks. CLINICAL IMPLICATIONS. The success of early decortication depends on recognizing the factors just discussed. The occurrence of infection in hemothorax does not change the essential pathological picture of hematoma organization, although a firm, thick membrane may develop more rapidly. The different clinical courses of posttraumatic and postpneumonic empyema must be recognized. Empyema following pneumonia can usually be treated by intercostal tube drainage, and it would be unusual to resort to thoracotomy. Posttraumatic empyema is due to infected organized clot, which is difficult to drain even with large-bore chest tubes [2,4,5,9,11,14,16, 18, 19, 22, 24-26]. The cause of infection is not quite clear in this series. It could have been due to contamination by the mode of injury, or it may have been secondary to pulmonary or abdominal sepsis, particularly since more than half of the patients were seriously ill and required respiratory support preoperatively. It could also very well have been related to the fact that many of these patients had chest tubes inserted under less than optimal sterile conditions. A few interesting facts were observed, however: (1)staphylococcal infection was more frequent in the group with the less serious injuries; (2) mixed organisms (such as klebsiella, E . coli, and pseudomonas) were found in the group with multiorgan injuries and longer respiratory support. The same organisms were frequently found in the tracheobronchial tree, suggesting invasion from this route; and (3) bacteroides organisms were found only in Group 3, in which empyema was believed to be secondary to intraabdominal infection.

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When would be the optimum time for decortication? From extensive study of the development of the process, it appears that the fibroblastic peel develops between one and three weeks after injury. The thick, inelastic fibrous tissue that invades the visceral pleura and underlying lung parenchyma does not become recognizable until after six to seven weeks. Therefore it seems logical that decortication should be performed within four weeks, before the fibrous peel develops. Another influential factor is the condition of the underlying lung. It has been shown that more than 90% of the patients achieved primary cure when the lung was normal at the time of decortication, whereas in patients with associated parenchymal disease some 40% had recurrent empyema [16]. Hence, if possible, decortication should be performed when the underlying lung is in optimum condition. In light of the above information, our patients have had decortication as soon as infection was evident and could not be controlled by tube drainage. This took approximately two weeks to establish. By that time, underlying lung problems such as pneumothorax, pulmonary contusion, edema, and sepsis should be well controlled. With modern anesthesia and monitoring devices, the risk of operation is low. Except for 1death due to severe abdominal trauma, the complications were not serious. Follow-up study revealed no late recurrence. Early decortication has several advantages: complete pulmonary reexpansion and removal of infected peel is immediate, chronic empyema with additional weeks of disability is prevented, and the patient is spared considerable discomfort from dressings and irrigations, duration of disability, and the devastating systemic effects of chronic pleural sepsis.

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