Prophylactic antibiotics in the treatment of penetrating chest wounds

Prophylactic antibiotics in the treatment of penetrating chest wounds A prospective double-blind study Considerable controversy exists as to whether or not antibiotics should be administered "prophylactically' to patients with penetrating chest trauma. No prospective study of this problem has been reported. Therefore, 75 patients with isolated, penetrating chest injury were randomized prospectively in a double-blind study. Group A patients (38 patients) were given 300 mg. of clindamycin phosphate every 6 hours, beginning with admission and lasting until 1 day following chest tube removal or for 5 days, whichever was shorter. Group B patients (37 patients) were given a placebo on the same schedule. The patients' hospital course, fever, white blood count, culture data, and roentgenograms were recorded serially. Clindamycin-treated patients had a significantly lower incidence of radiographic pneumonia, less fever, and a lower incidence of positive pleural and wound cultures. They acquired empyema less frequently, required fewer operations, and had a shorter period of hospitalization. Antibiotics may be useful, therefore, as adjunctive therapy in the management of penetrating chest trauma.

Frederick L. Grover, M.D., J. David Richardson, M.D. (by invitation), John G. Fewel, B.A. (by invitation), Kit V. Arom, M.D. (by invitation), George E. Webb, M.D. (by invitation), and J. Kent Trinkle, M.D., San Antonio, Texas

Pleural sepsis is a complication of penetrating chest trauma, sometimes necessitating decortication. This subject received considerable attention in World War IF and continued to be a problem in the Vietnam War," despite the availability of antibiotics. The incidence of empyema following chest wounds has varied considerably in both civilian and military practice. An incidence of 2 percent was observed in the preantibiotic era at Emory University from 1922 to 1935, and an incidence of 3 percent from 1948 to 1958, during which time all patients received antibiotics. In two World War II studies in which most patients were treated with either penicillin or sulfonamides and thoracentesis, incidences of empyema of 9.7 and 5 percent were found.s- 6 Valle," reporting on a Korean War experiFrom the Division of Cardiothoracic Surgery, Audie L. Murphy Veterans Administration Hospital, and The University of Texas Health Science Center, San Antonio, Texas. Read at the Fifty-seventh Annual Meeting of The American Association for Thoracic Surgery, Toronto, Ontario, Canada, April 18, 19, and 20, 1977. Address for reprints: Frederick L. Grover, M.D., The University of Texas Health Science Center, 7703 Floyd Curl Dr., San Antonio, Texas 78284.

528

ence, noted that hemothoraces became infected in 26 percent of cases, but that 80 percent of the patients recovered with thoracentesis and antibiotics. Conn and co-workers 8 found empyema to occur in 1.6 percent of patients who were treated with needle aspiration plus penicillin and streptomycin in a civilian practice, and Smyth, Hughes, and Cornwell" reported a 2.1 percent incidence with drainage and antibiotics. Virgilio'? reported empyemas occurring in 1.6 percent of patients treated with tube thoracostomy plus penicillin and streptomycin during the Vietnam War. In a series of 14 children who had sustained penetrating chest injuries in Vietnam, II none developed empyema and all were treated with tube drainage and antibiotics. In the SixDay War (Israel) in 1967, one patient out of 76 treated with tube drainage and antibiotics developed a lung abscess, and during the Yom Kippur War (1973), there were no pleural infections with this treatment in 61 patients;'! However, there was a 20 percent incidence of infection in those undergoing early thoracotomy. Incidences of empyema of 1.5 and 0.5 percent were noted at Martin Luther King Hospital in Los Angeles in two recent publications, 13, 14 without the routine administration of antibiotics.

Volume 74 Number 4 October, 1977

Penetrating chest wounds

529

Table I

Group A (CP)

27

Group B

27

36M 2F 31M 6F

14GSW 24 SW 10 GSW 27SW

Chest tube drainage (mi.)

Chest tube duration (days)

Days ofdrug treatment

Follow-up (%)

25

31

646

5.0

4.7

87

29

31

565

5.2

5.1

87

Legend: CP, Clindamycin phosphate. GSW, Gunshot wound. SW, Stab wound.

Table II. Pleural culture organisms Present on admission

I

Group B

GroupA (CP)

0 0 0 0

0 0 0 0 0 2

I I I

o

2

I 2 3

0

I

0 0

0

GroupA (CP) Hemophilus influenza Hemophilus parainfluenza Alpha Streptococcus Microaerophilic Streptococcus Staphylococcus aureus Staphylococcus epidermidis Escherichia coli Enterococcus Proteus

I

Total

I I

0

o o o o o

Group B

o o

2 I I

For legend see Table I.

Therefore, a rather wide variation in the incidence of infectious complications of penetrating thoracic trauma has been noted over the years, and whether or not antibiotics alter the outcome is unclear. A double-blind prospective study to determine whether anitbiotics administered shortly after penetrating chest injury would be advantageous or harmful never has been performed. Therefore, the following study was undertaken. Methods

Seventy-five patients with isolated penetrating chest wounds were randomized prospectively in a doubleblind study to determine the efficacy of "prophylactic" antibiotics. All patients underwent tube thoracostomy with a povidone-iodine scrub and sterile draping. Blood volume was restored as indicated. Group A patients (38 patients) were given 300 mg. of clindamycin phosphate intravenously every 6 hours, beginning at admission and continuing until I day following chest tube removal, or for 5 days, whichever period was shorter. The drug was administered intramuscularly after being discontinued intravenously. Group B patients (37 patients) were given a placebo on the same schedule. The placebo was packaged identically to the clindamycin phosphate and had the same appearance, so that neither nursing staff or physicians knew whether the patient was receiving drug or placebo. The identity was known only to the pharmacist. The patients' hos-

pital course, temperature, white blood cell counts, culture data, and chest roentgenograms were recorded serially. Pregnant women, children under 12 years of age, and patients with associated extrathoracic injuries were excluded from the study. Consent for the study was obtained from the patients on admission, with the understanding that the patient could withdraw from the protocol at any time he wished. If a patient appeared to be septic or if operation became necessary, he was discontinued from the study and was treated appropriately. Data were tabulated, averaged, and analyzed statistically for the two groups before the authors were aware of which group had received clindamycin phosphate and which had received the placebo. Results

Age, sex, and injury. Both groups were comparable in age, sex, and type and magnitude of injury (Table I). The average age in the two groups was 27 years and ranged from 13 to 73 in Group A and from 13 to 52 in Group B. There were 36 male and two female patients in Group A and 31 males and six female patients in Group B. Group A comprised 14 gunshot wounds and 24 stab wounds, as compared to iO and 27, respectively, in Group B. Twenty-five hemothoraces and 31 pneumothoraces were noted in Group A, as compared

530

The Journal of

Grover et al.

Thoracic and Cardiovascular Surgery

14

90 80

12

P=N.S.

P=N.S

10

70 Cf)

IZ

w 60

ro

~

a.. LJ...

0

8

Q

x

50

6 N=38

w

± S.EM.

C)


IZ W

u

0: W

4

25/38 2

30

a..

20

GROUPA(CP)

Fig. 2. The white blood cell count on the third day after injury. White blood cell count was 10,690 in Group 8 (control), and 9,640 in Group A (c1indamycin).

10

GROUP A(CP)

GROUP B

Fig. 1. Elevation of white blood cell count (WBC). The WBC exceeded 10,000 in 80 percent of Group B (control), as compared to 66 percent of Group A (c1indamycin).

to 29 and 31 in Group B. Some patients in both groups had a hemopneumothorax. The average chest tube drainage was somewhat greater in Group A, being 646 ml., as compared to 565 mI. in Group B. Chest tubes remained in Group A patients for an average of 5 days and in Group B patients for 5.2 days. White blood cell counts. The white blood cell count was elevated (greater than 10,000) in 81 percent of Group B patients, as compared to 66 percent of the clindamycin-treated patients. (Fig. I). The average white blood cell count on the third hospital day was 10,690 ± 490 (S.E.M.) in the Group B patients and 9,640 ± 420 in the clindamycin-treated group (Fig. 2). The average highest white count per patient was 13, 100 ± 630 in Group B, as compared to 11,860 ± 489 in Group A. Although these values all were higher in Group B, the differences between the groups were not statistically significant. Temperature. Group A patients (clindamycin treated) had an average of 4.7 ± .5 (S.E.M.) days of fever, as compared to 5.5 ± .4 for Group B. Seventeen of 37 patients (46 percent) had a temperature above 10I 0 F. in Group B, whereas only 11 of 38 (29 percent) exceeded this level in the clindamycin-treated group (Fig. 3). The average peak temperature per pa-

tient in Group A was 100.4 ± 0.2 F. and was 100.8 ± 0.2 in Group B. The difference between groups having a temperature greater than 10I 0 F. was almost significant. Radiographic changes. Thirteen patients in Group B (35 percent) were noted to have evidence of pneumonia on chest roentgenogram, as compared to four patients (10.5 percent) in the clindamycin-treated group (p < 0.03) (Fig. 4). The incidence of atelectasis was similar between groups, being 41 percent in Group Band 37 percent in Group A. Clinical empyema. Patients with prolonged fever, persistent pleural effusion exhibited by roentgenogram, and who required some type of pleural drainage procedure were classified as having clinical empyema. Organisms were cultured in all but one of Group A patients who were in this category. Patients who had positive chest tube cultures but who did not appear to be in a toxic condition and who had no evidence of persistent pleural effusion by roentgenogram were not considered to have clinical empyema. Six patients (16.2 percent) in Group B were found to have clinical empyema, as compared to one patient (2.6 percent in Group A (Fig. 5) (p < 0.11). Wound infection. Wounds were considered to be infected if gross pus or considerable surrounding erythema was present. The presence of organisms in the absence of these clinical signs did not qualify as an infection. Almost all wounds were left open, with a 0

0

Volume 74

Penetrating chest wounds

Number 4

53I

October, 1977

50

40

40

IJJ C)

30


tZ

IJJ

P= N.S.

u

P<.03

0::

IJJ

IJJ

a.. 20

30

~

z

IJJ

U 0::

IJJ

a.. 20

11/38

10

4/38 10 GROUP A (CP)

GROUP B

Fig. 4. Incidence of pneumonia. Radiographic pneumonia was present in 35 percent of Group A (control) patients, and in only 10.5 percent of Group B (c1indamycin) patients (p

GROUPA(CP)

Fig. 3. Patients with fever exceeding 101 F. Forty-six percent of Group B (control) patients developed fever of greater than 10I F., as compared to only 29 percent of c1indamycintreated patients (Group A).

< 0.03).

0

30

0

resultant low incidence of clinical infection of 2.6 percent in Group A and 5.4 percent in Group B. Pleural culture. Pleural cultures were obtained from 21 patients of Group A and from 18 of Group B. Nineteen percent were positive in Group A and 33 percent in Group B (Fig.6). The organisms cultured are noted in Table II. Hemophilus and Staphylococcus epidermidis accounted for the majority of organisms in Group A, whereas Staphylococcus aureus, microaerophilic streptococci, and various other organisms were cultured in Group B. Wound and sputum cultures. Wound cultures were obtained in few patients in each group. Five of 11 (45 percent) were positive in Group A and seven of nine (78 percent) in Group B. The organisms cultured are listed in Table III. Staphylococcus epidermidis was the organism cultured most frequently in each group. Sputum cultures were obtained from approximately half of the patients and were positive in 83 percent of Group A and 50 percent of Group B. Table IV, which lists the organisms cultured, reveals that most Group A organisms were Hemophilus 11 and that Candida was

w

~~

0::

20

W

a..

10

Fig. 5. Clinical empyema. Only one patient in Group A (c1indamycin) was found to have clinical empyema, as compared to six patients in Group B (control). cultured from two patients. Of interest is the fact that beta hemolytic Streptococcus was cultured in four cases. Operations required. Operative intervention (in addition to closed-chest tube thoracostomy) was required in 3 percent of Group A patients and 16 percent of Group B patients (p < 0.11) (Fig. 7). The one operation for Group A was a decortication for a clotted

532

The Journalof Thoracic and Cardiovascular Surgery

Grover et al.

40

9

35

8 P=N.S.

en

7

~ 30

w

~

a: 25

P=N.S.

6

u,

o w

20

~

15

~z

a::

If)

5

~

Cl

4

w

11.

10

4/21

3

5

N=38 ±SEM

2 GROUPA (CP)

Fig. 6. Pleural cultures. Organisms were cultured from Group B (control) slightly more frequently than from Group A (clindamycin). ~

z

30

w

fi11. u,

o

GROUP B

Fig. 8. Average hospital stay. Group A (clindamycin) patients were hospitalizedan average of I day less than Group8 (control) patients. 60

w

20

C)

w ~

IZ W

~ W

GROUP A (CP)

P< .11 10

4 -DECORTICAT1ONS I-OPEN TUBE THORACOS1OMY 1-BRONCHOSCOPY

11.

~ 50 z w u

ffi

11.

40

30 20 GROUP A (CP)

GROUP B

Fig. 7. Operations. Group A (clindamycin) patients required fewer operations (3 percent) than did Group B (control) patients (16 percent). hemothorax. Although the patient is listed as having a clinical empyema, pleural cultures were negative, and the highest white blood cell count was 9,700. Four decortications were performed in Group B patients, all of whom had definite empyemas with positive pleural cultures. One patient in Group B was treated with open-chest tube thoracostomy for drainage of a definite empyema, and one treated with a bronchoscope for a persistent pneumonia and atelectasis. Length of hospitalization. Group B patients were

paN.S. 10

3/38 GROUP A (CP)

GROUP B

Fig. 9. Hospitalization exceeding IO days. Twenty-fourpercent of Group B (control) patients were hospitalizedfor 10 or more days, as compared to only 8 percent of Group A (clindamycin). hospitalized longer than Group A patients, averaging 7.7 ± 0.6 (S.E.M.) days as compared to 6.7 ± 0.6 (Fig. 8). Twenty-four percent of Group B patients were hospitalized 10 or more days, whereas only 8 percent of Group A were hospitalized this long (Fig. 9).

Volume 74

Penetrating chest wounds

Number 4

533

October, 1977

Table III. Wound culture organisms Present on admission Group A (CP) Staphylococcus epidermidis Staphylococcus aureus Alpha Streptococcus Klebsiella Citrobacter

I

Total

GroupB

2

5

o

o

o o o

o o o

Group A (CP)

I

GroupB 5 I

4

o

o

I

o o

I I

For legend see Table I.

Table IV. Sputum culture organisms Total

Present on admission Group A (CP) Hemophilus infiuenzae Hemophilus parainfluenza Hemophilus hemolyticus Beta Streptococcus Streptococcus pneumoniae Staphylococcus epidermidis Staphylococcus aureus Enterobacter Klebsiella Proteus Escherichia coli Citrobacter Candida

I 2 0 3 0 0 0 0 0 0 0 0 I

I

Group B

0 0 I

0 2 0

Group A (CP)

I

Group B

6

4

4 I 4

0

0 I

I 2

0

0 0 0 0 0

0 0 0 0 3

I

I I 4

0 3 2 2 I I I

0

For legend see Table I.

Discussion

As noted previously, there has been considerable variation in the antimicrobial management of penetrating thoracic wounds. It appears that most centers now utilize tube thoracostomies for pleural drainage, rather than repeated thoracentesis, which was popular during the World War II and Korean War periods. Comparable incidences of pleural sepsis following penetrating trauma have been reported from institutions that routinely use antibiotics as an adjunct to treatment': 8. 10-12 and from those that do not.P: 14 The prophylactic administration of antibiotics has been shown to be helpful in certain other circumstances. Alexander and Altemeier'" found that penicillin G was effective in preventing wound infections after experimentally controlled contamination of wounds with penicillin-sensitive Staphylococcus aureus. This protection was most effective if the penicillin was given before or during the operative period, rather than later. In a retrospective study of penetrating abdominal trauma, Fullen, Hunt, and Altemeier!" found that if antibiotics (penicillin G and either tetracycline or

chloramphenicol) were administered before operation, the infectious complication rate was 7 percent, but if given during or after operation, it was approximately 80 percent. In colon injuries, postoperative sepsis occurred in II percent of patients treated prior to operation, in 57 percent of those treated during operation, and in 70 percent of those treated after operation. Weinstein and co-workers'? experimentally inserted colonic contents into the peritoneal cavity of rats and found that the combination of gentamicin and clindamycin reduced the mortality rate from 37 to 7 percent, and the incidence of intra-abdominal abscesses from 100 to 6 percent. Polk and Lopez-Mayor.l" in a double-blind, randomized clinical study, found that prophylactic administration of cephaloridine reduced the frequency of wound and intra-abdominal infections in elective gastric, small, and large bowel procedures. Moore, Rosson, and Hall'" found that prophylactic antibiotic therapy prevented or reduced vascular graft infection in a double-blind randomized animal study. However, Karl and associates" found no decrease in wound infection or pulmonary infections in a

534

The Journal of Thoracic and Cardiovascular Surgery

Grover et al.

double-blind study involving various operative procedures where methicillin and chloramphenicol were administered to 168 patients before, during, and immediately after operation. The drugs were given only once in the postoperative period, however. Klein, Berger, and Yekutiel'" reviewed 88 episodes of wound infection in 624 casualties of the Yom Kippur War. They noted that 91 percent of the infections were acquired during a period of antibiotic therapy or prophylaxis, and that gram-negative bacilli and mixed infections predominated. Seventy-nine percent of the infections were below the diaphragm, however, and no specific mention of chest injuries was made. Pseudomonas infection was noted most frequently and usually was associated with the administration of ampicillin, a penicillinase-resistant penicillin, or both. Altemeier and colleagues'" reviewed the surgical infections at their institution over 28 years and noted an increase in gram-negative infections with a relative decrease in gram-positive infections. They also noted superimposed or secondary infections occuring during antibiotic therapy and increasing infections owing to fungi and viruses. Caution in the use of prophylactic antibiotics also was voiced by Schlenker and Barrios.P who reviewed the cases of five patients who died during a 6 month period following general surgical procedures. All died of gram-negative pneumonias which developed during postoperative broad-spectrum prophylactic antibiotic coverage. Tillotson and Finland-" found that a secondary infection developed in 59 percent of 149 patients treated for pneumonia. Therefore, these potential hazards of antibiotic therapy need to be considered carefully against the possible advantages of antibiotic prophylaxis. Clindamycin phosphate was chosen as the experimental drug for this protocol because of its activity against both the aerobic gram-positive cocci (staphylococci, streptococci, and pneumococci) and the anerobic gram-positive and gram-negative pathogens (Clostridium species, Peptococcus, Peptostreptococcus, microaerophilic streptococci, and Bacteroides speciesj.P It is a penicillinase-resistant agent, and at the time the study was initiated, it was thought to be a relatively nontoxic agent with only rare allergic reactions, usually in the form of skin rashes. Our study has demonstrated a statistically significant decrease in the incidence of radiographic pneumonia in those patients receiving clindamycin phosphate. In addition, much of the data in the other parameters measured are very suggestive, although not quite statistically significant, that the antibiotics were useful in decreasing infectious complications. Patients so treated demonstrated less fever, lower white blood cell counts,

less frequent empyema, required fewer operations, had fewer positive pleural and wound cultures, and required a shorter period of hospitalization. The only parameter measured which was not in favor of the antibiotics was the sputum culture. However, most of these positive cultures were Hemophilus, which frequently is considered to be normal flora, and these apparently were not clinically significant. It should be emphasized that this is a double-blind, randomized, prospective study with no bias. The data were tabulated and analyzed statistically before the authors were informed which group had received antibiotics and which had not. Although the majority of papers in the literature reported routine use of antibiotics, a few of the reports cite a low incidence of infectious complications without them. None of these reports, however, compares the effects of prophylactic antibiotics in the same patient population, by the same physicians, in a prospective, randomized, blind manner. Much of the literature which is negative in regard to prophylaxis is comprised of retrospective studies, where the comparability and analysis of the groups are suspect. Unfortunately, this study was terminated prematurely because of the authors' concern over recent reports of diarrhea and pseudomembranous colitis after clindamycin therapy-"- 27 It was felt that this sort of risk for a clinical investigative study could not be justified. It is unfortunate, because many of the parameters measured were close to statistical significance, and more definitive conclusions perhaps could have been made with a larger population. It is interesting, however, that the only complication observed in the 38 patients who received clindamycin was skin rash in one patient. Conclusions In this prospective, randomized, double-blind study of 75 patients with isolated penetrating chest trauma, the group receiving clindamycin phosphate had statistically significant lower incidence of. radiographic pneumonia, less fever, and lower white blood cell counts; they acquired empyema less frequently, had a lower incidence of positive pleural and wound cultures, required fewer operations, and had a shorter period of hospitalization. Antibiotics may be useful, therefore, as adjunctive therapy in the management of penetrating chest trauma.

REFERENCES Burford, T. H., Parker, E. F., and Samson, P. C.: Early Pulmonary Decortication in the Treatment of Posttraumatic Empyema, Ann. Surg. 122: 163, 1945.

Volume 74

Penetrating chest wounds

Number 4 October, 1977

2 Levitsky, S., Annable, C. A., and Thomas, P. A.: The Management of Empyema After Thoracic Wounding, J. THORAc. CARDIOVASC. SURG. 59: 630, 1970. 3 Boland, F. K.: Traumatic Surgery of the Lungs and Pleura, Ann. Surg. 104: 572, 1936. 4 Gray, A. R., Harrison, W. H., Jr., Couves, C. M., and Howard, J. M.: Penetrating Injuries to the Chest, Am. J. Surg. 100: 709, 1960. 5 Johnson, J.: Battle Wounds of the Thoracic Cavity, Ann. Surg.123: 321,1946. 6 Montgomery, H., Halbersleben, D., and Carr, F. B.: Puncture Wounds of the Chest, J. THORAc. SURG. 16: 407, 1947. . 7 Valle, A. R.: An Analysis of 2,811 Chest Casualties of the Korean Conflict, Chest. 26: 623, 1954. 8 Conn,1. H., Hardy, 1. D., Fain, W. R., and Netterville, R. E.: Thoracic Trauma: Analysis of 1,022 Cases, J. Trauma 3: 22, 1963. 9 Smyth, N. P. D., Hughes, R. K., and Cornwell, E. E.: Penetrating Thoracic Wounds, Am. Surg. 27: 770, 1961. 10 Virgilio, R. W.: Intrathoracic Wounds in Battle Casualties, Surg. Gynecol. Obstet. 130: 609, 1970. II Bellinger, S. B.: Penetrating Chest Injuries in Children, Ann. Thorac. Surg. 14: 635, 1972. 12 Romanoff, H.: Prevention of Infection in War Chest Injuries, Ann. Surg. 182: 144, 1975. 13 Leacock, F. S., Arthur, B. c., and Tildon, T. T.: Penetrating Wounds of the Chest, J. Natl. Med. Assoc. 67: 149, 1975. 14 Oparah, S. S. and Mandai, A. K.: Penetrating Stab Wounds of the Chest: Experience with 200 Consecutive Cases, J. Trauma 16: 868, 1976. 15 Alexander, J. W. and Altemeier, W. A.,: Penicillin Prophylaxis of Experimental Staphylococcal Wound Infections, Surg. Gynecol. Obstet. 120: 243, 1965. 16 Fullen, W. D., Hunt, J., and Altemeier, W. A: Prophylactic Antibiotics in Penetrating Wounds of the Abdomen, J. Trauma 12: 282, 1972. 17 Weinstein, W. M., Onderdonk, A. B., Bartlett, 1. G., Louie, T. J., and Gorbach, S. L.: Antimicrobial Therapy of Experimental Intra-abdominal Sepsis, 1. Infect. Dis. 132: 282, 1975. 18 Polk, H. c.. Jr. and Lopez-Mayor, J. F.: Postoperative Wound Infection: A Prospective Study of Determinant Factors and Prevention, Surgery 66: 97, 1969. 19 Moore, W. S., Rosson, C. T., and Hall, A. D.: Effect of Prophylactic Antibiotics in Preventing Bacteremic Infection of Vascular Protheses, Surgery 69: 825, 1971. 20 Karl, R. c., Mertz, J. J., Veith, F. J., and Dineen, P.: Prophylactic Antimicrobial Drugs in Surgery, N. Engl. J. Med. 275: 305, 1966. 21 Klein, R. S., Berger, S. A., and Yekutiel, P.: Wound Infection During the Yom Kippur War, Ann. Surg. 182: 15, 1975. 22 Altemeier, W. A., Hummel, R. P., Hill, E. 0., and Lewis, S.: Changing Patterns in Surgical Infections, Ann. Surg. 178: 436, 1973. 23 Schlenker, J. D., and Barrios, R.: Gram-negative

24

25

26

27

535

Pneumonias in Surgical Patients, Arch. Surg. 106: 267, 1973. Tillotson, J. R., and Finland, M.: Bacterial Colonization and Clinical Superinfection of the Respiratory Tract Complicating Antibiotic Treatment of Pneumonia, J. Infect. Dis. 119: 597, 1969. Keusch, G. T. and Present, D. H.: Summary of a Workshop on Clindamycin Colitis, J. Infect. Dis. 133: 578, 1976. Tedesco, F. J., Barton, R. W., and Alpers, D. H.: Clindamycin-Associated Colitis, Ann. Intern. Med. 81: 429, 1974. Levine, B., Peskin, G. W., and Saik, R. P.: DrugInduced Colitis as a Surgical Disease. Arch. Surg. III: 987, 1976.

Discussion DR. LESTER R. BRYANT New Orleans, La.

Dr. Grover and his associates certainly have drawn our attention to an area that has been incompletely studied to this date. I hope they will be able to resume their study with a different antibiotic or under different circumstances. We certainly do not have proper information about the correct attitude toward prophylactic antibiotics in patients with chest injuries, despite the fact that we see large numbers of such patients. To help us plan a prospective study for prophylactic antibiotics in patients with thoracic trauma, we recently completed a review of 734 patients who had either gunshot wounds or stab wounds of the chest at the Charity Hospital in New Orleans. Of that number, 475 patients had received prophylactic antibiotics; that is, they began receiving antibiotics within a few hours after they were admitted to the hospital. Fifty-eight percent of the patients had been stabbed and 42 percent had gunshot wounds. Empyema developed in nine of these patients, and in approximately 50 there were changes on the chest x-ray film that were interpreted as pneumonitis, although in retrospect some may have been only atelectasis. Another group of 89 patients started to receive antibiotics more that 24 hours following admission because of elevations in temperature or other clinical signs which suggested infection. Among these 89 patients who received "therapeutic antibiotics," there was a 15 percent incidence of empyema and a 19 percent incidence of pneumonitis. In other words, evidence of empyema developed subsequently in 13 patients. There were 170 patients who received no antibiotics at any time. One patient had empyema, and a very small number of patients had changes thought possibly to be the result of pneumonitis, but because of the question of atelectasis, they did not receive antibiotics. If I had no source of information other than Dr. Grover's study, I would be persuaded to use prophylactic antibiotics in all patients with penetrating chest injuries. However, in view of our data and the relatively low incidence of empyema (only 24 cases in a total of 734 patients), I believe that we do not have a final answer. There must be other factors that we can

536

Grover et al.

examine, other data that would differentiate more clearly between patients who should have antibiotics and those who should not. DR. G R 0 V E R (Closing) I would like to thank Dr. Bryant for his comments. This is a very confusing area, because similarly low incidences of empyema occur in some institutions that employ antibiotics and in some that do not. Conversely, rather high incidences of empyema have been reported by both users and nonusers of antibiotics. It is very difficult to reach conclusions without a prospective, double-blind study performed at one institution, because otherwise there are a different patient mixes, different methods of treatment, and frequently different years involved. Some institutions will report on one group of patients treated without antibiotics over a period of years and then on another group who received antibiotics over a chronologically different period of years. This is what we tried to eliminate in this study. The patients were treated by

The Journal of Thoracic and Cardiovascular Surgery

the same doctors and the same techniques over the same period of time. Of course, there are other important factors besides antibiotic administration. One of the most important factors in preventing empyema is early evacuation of the pleural space with complete expansion of the lung. Our incidence of empyema is slightly higher than that of some institutions and may be related to this in part. However, this factor should affect both our control and antibiotic groups. Unfortunately, we terminated this study before we wanted to because of our worry over the possibility of clindamycininduced colitis. There was significantly less pneumonia in the antibiotic-treated group, however, and suggestive evidence of less morbidity with the use of antibiotics in the other parameters measured. Although we believe that the data support the use of antibiotics in these patients, I would encourage everyone to evaluate our data carefully in order to make their own decision.