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CLINICAL ARTICLES
The Epidemiology of Chest and Leg Wound Infections Following
Cardiothoracic Surgery
Paul B. L'Ecuyer, Denise Murphy, J. Russell Little,
and Victoria J. Fraser
From the Division of Infectious Diseases, Washington University School
of Medicine, and the Department of Infection Control, Barnes Hospital,
Barnes-Jewish-Christian Health System, St. Louis, Missouri
The occurrence of wound infections following cardiothoracic surgery has significant implications.
However, the epidemiology of all chest and leg wound infections is infrequently described, and the
effects on morbidity, mortality, and cost of care remain undefined. We identified 182 superficial
and deep chest and leg infections in 163 patients following 1,554 coronary artery bypass graft
(CABG), valve, and CABG/valve procedures over 30 months. The overall infection rate was 11.7%;
infections of specific sites involved in the 1,554 procedures occurred at the following rates: 3.1%,
superficial chest wounds; 2.3%, deep chest wounds; 4.6%, superficial leg wounds; and 2.2%, deep
leg wounds. Chest infection rates were similar for all procedures. Multiple infections occurred in
9.8% of patients and were associated with female sex, diabetes, and prolonged surgery (P < .05).
Purulent drainage and fever were more common in chest infections; erythema and pain were more
common in leg infections (P < .05). Staphylococcus aureus (32.9%), coagulase-negative staphylococci
(27.4%), and Enterobacteriaceae (26.0%) were identified most commonly. Enterobacteriaceae were
more commonly isolated from leg wounds (P < .05). Adverse outcomes included reexploration
(20.9%), flap surgery (12.3%), and death (4.3%). All adverse outcomes were more commonly associated with deep chest infections (P < .05), but superficial chest and leg infections also had a substantial
impact on cardiothoracic surgery-related morbidity. Studies are needed to define site-specific risk
factors so that the full potential of prevention and control measures can be realized.
Wound infections contribute substantially to morbidity and
mortality following cardiothoracic surgery [1-4]. Deep chest
infections may extend to contiguous vital structures, require
debridement, result in disfigurement, and have a 10%-40%
mortality [3, 5-12]. Total costs are particularly high for treatment of wound infections associated with cardiothoracic surgical procedures, of which >600,000 are performed annually in
the United States [2, 3, 5, 13-17]. Prevention and control of
cardiothoracic surgical wound infections has become a vital
component of quality assurance and hospital cost-containment
over the last decade [2, 5, 14-16].
Intensive surveillance of surgical wounds reduces the rate
of infection by 20%-50% [1, 2, 4, 18, 19]. Such efforts are
costly and time-consuming, but prior stratification by wound
class can identify the highest-risk patients for focused surveillance [20, 21]. Recently, the Centers for Disease Control and
Prevention (CDC) estimated the surgical wound infection risk
associated with cardiothoracic procedures to be 1.03%-33.0%
[21]. Development of a cardiothoracic-specific risk index
would provide a more sensitive tool for prevention efforts
[21, 22].
Much of the literature on cardiothoracic surgical wound infections was published before 1990 and focused on deep chest
infections, occurring at rates of 0.5%-5.0% [5-12,23-31],
and the multiple risk factors identified [2, 5- 9, 11-14, 17,
23-44]. However, the rates and characteristics of and risk
factors for superficial chest infections and both superficial and
deep leg infections complicating cardiothoracic surgery are infrequently described [14, 17, 45], and their effects on morbidity, mortality, and cost of care remain undefined. This article
describes the clinical nature and outcome of all chest and leg
infections following coronary artery bypass graft (CABG),
valve, and combined CABG/valve surgery that were identified
by prospective surveillance at Barnes Hospital (St. Louis) from
April 1991 through September 1993.
Methods
Received 4 April 1995; revised 6 July 1995.
Reprints or correspondence: Dr. Victoria J. Fraser, Campus Box 8051, 660
South Euclid Avenue, Division of Infectious Diseases, Washington University
School of Medicine, St. Louis, Missouri 63110-1093.
Clinical Infectious Diseases
1996;22:424-9
© 1996 by The University of Chicago. All rights reserved.
1058-4838/96/2203-0004$02.00
Barnes Hospital is a 1,000-bed tertiary care facility affiliated
with Washington University School of Medicine. Cardiothoracic surgeons at the facility perform ,....., 800 procedures per year
(70% are performed on patients referred from outside the St.
Louis area), including 650 CABG, valve, and combined
CABG/valve operations. The cardiothoracic surgery staff in-
cm
1996;22 (March)
Wound Infections Following Cardiothoracic Surgery
cludes 7 attending physicians, 4 cardiac fellows, 4 surgical
assistants, 2 nurse specialists, and 2 rotating house-staff members. Patients take a chlorhexidene shower the night before
surgery; on the morning of surgery, the chest hair is removed,
and then a I-minute skin scrub with povidone/iodine is followed by application of povidone/iodine solution to the skin
site(s). Prophylactic intravenous antibiotics (cefazolin [1 g] or
vancomycin [1 gD are administered 30-120 minutes prior to
incision and are given intraoperatively during prolonged procedures. Prophylactic antibiotic therapy is continued postoperatively until removal of the thoracostomy tubes. Attending physicians and fellows are directly involved in the primary
procedure. Vein harvesting is performed by surgical assistants.
One infection control nurse reviews microbiology logs, floor
wound infection logs, and floor nursing reports to detect potential wound infections. Formal postdischarge surveillance is not
performed. Microbiology reports are screened with use of two
expert computer systems (GermWatcher and GermAlert, Medick Informatics, Washington University, St. Louis) previously
validated by infection control staff [46]. Wound infections are
confirmed by direct bedside examination and review of medical
records, with use of National Nosocomial Infection Surveillance (NNIS) System definitions [4]. In this series, deep incisional and deep organ-space infections were considered together as deep wound infections because of the difficulty of
distinguishing the two in the chest.
Data concerning demographics, preexisting medical conditions, infections at other sites within 30 days before surgery,
intraoperative variables, wound infection sites, and wound culture results were collected for all patients with wound infections.
The intraoperative use of ~5 units of packed RBCs defined
multiple transfusions. A lengthy procedure exceeded 300 minutes, on the basis of the CDC risk index criteria [21]. Emergent
operations immediately followed emergent admission and/or
catheterization, and urgent operations were performed within 24
hours of catheterization. Timely administration of the prophylactic antibiotic required initial dosing within 120 minutes before
incision. Outcome analysis was based on the most morbid (chest
and/or deep) infection for patients with multiple infections.
Length of stay included all days of the hospitalization for surgery
as well as additional days during subsequent hospitalization(s)
for treatment of the wound infection(s).
Data were analyzed with the PC SAS program (SAS Institute, Cary, NC). Categorical variables were analyzed by univariate analysis with the X2 or Fisher's exact test. Continuous
variables were analyzed with the Student's I-test (for data with
Gaussian distribution) and the Mann-Whitney test (for data
with non-Gaussian distribution). A P value of < .05 was considered significant on two-tailed testing.
Results
Infection Rates
Prospective surveillance identified 182 wound infections
in 163 patients undergoing CABG, valve, and combined
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CABG/valve surgery from April 1991 through September 1993
(table 1). For 1,554 procedures, the total wound infection rate
was 11.7%. The wound infection rate was significantly higher
for combined CABG/valve vs. CABG surgery (18.3% vs.
11.8%; P = .032). Specific rates of infection among the 1,554
procedures were as follows: 3.1%, superficial chest wounds;
2.3%, deep chest wounds; 4.6%, superficial leg wounds; and
2.2%, deep leg infections. Deep leg infections were more common following combined CABG/valve surgery than following
CABG surgery (4.8% vs. 2.0%; P = .045). The mean duration
of the procedure was longer for infected CABG/valve surgery
patients than for infected CABG surgery or valve surgery patients (361.9 minutes vs. 309.9 minutes and 337.0 minutes,
respectively; P = .013 and P = .612, respectively). Infected
CABG/valve surgery patients were older than infected CABG
surgery or valve surgery patients (mean ages, 69.8 years, 64.5
years, and 53.8 years, respectively), but the differences were
not statistically significant.
Characteristics of Patients with Wound Infections
Preexisting medical conditions were common, including
smoking (49.7%), diabetes (45.4%), congestive heart failure
(40.5%), and obesity (23.9%). Prior infections, documented on
21 occasions in 18 patients (11.0%), included urinary tract
infections (10), pneumonia (6), primary bacteremia (4), and
purulent phlebitis (1). The mean duration of hospitalization
prior to surgery was 8.9 days (range, 0-366 days). Approximately 50% of procedures were urgent or emergent, and 47.9%
were lengthy. Preoperative hair removal was documented in
39 (48.8%) of 80 cases and was done with a disposable razor
(30.0%), clipper (11.3%), or electric razor (7.5%). Only 83.4%
of patients received timely antibiotic prophylaxis.
Most patients (63.2%) had wound infections diagnosed during the initial hospitalization; of the remainder, 30.1 % required
readmission for treatment of wound infections. Wound infections were identified an average of 21.9 days (range, 3-176
days) following surgery. Excluding 35 infections identified
> 30 days after surgery, we found that the mean time to diagnosis of the other 147 wound infections was 13.2 days after
surgery. Single-site infections occurred in 147 patients (90.2%),
affecting 75 chests (41 superficial and 34 deep wounds) and
72 legs (48 superficial and 24 deep wounds). Patients with
single chest infections were more likely than those with single
leg infections to be smokers (61.3% vs. 43.1 %; P = .027) and
obese (32.0% vs. 13.9%; P = .009). Patients with single leg
infections were older (mean of 67.3 years vs. 61.6 years;
P = .001), were more commonly female (47.2% vs. 30.7%;
P = .039), and more commonly received multiple transfusions
than did patients with single chest infections (19.4% vs. 8.0%;
P = .043).
Thirty-five multiple-site infections occurred in 16 patients
(9.8%), affecting 10 chests (8 superficial and 2 deep wounds)
and 25 legs (17 superficial and 8 deep wounds). Most patients
L'Ecuyer et al.
426
Table 1.
cm
1996;22 (March)
CABG/valve
P value
Comparison of wound infection rates in relation to cardiothoracic procedure.
Data per indicated procedure
Variable
All procedures
Total no. of procedures
No. (%) of patients with wound infection
Total no. of wound infections
(% of total procedures)
Chest, superficial
Chest, deep
Leg, superficial
Leg, deep
Days to detection, mean no. (range)
NOTE.
CABG
1,554
163 (10.5)
CABG
Valve
1,301
138 (10.6)
127
5 (3.9)
154 (11.8)
40 (3.1)
32 (2.5)
56 (4.3)
26 (2.0)
21.6 (3-176)
182 (11.7)
49 (3.1)
36 (2.3)
65 (4.6)
32 (2.2)
21.9 (3-176)
5 (3.9)
4 (3.1)
I (0.8)
0
0
16.4 (9-31)
126
20 (15.9)
23 (18.3)
5 (4.0)
3 (2.4)
9 (7.1)
6 (4.8)
22.2 (6-65)
NA
<.05
<.05
NS
NS
NS
.045
NS
= coronary artery bypass graft; NA = not applicable.
(10 of 16) with multiple infections had both chest and leg
involvement. Development of multiple infections was associated with female sex (11 of 16, vs. 57 of 147 with single
infections; P = .021), diabetes (11 of 16 vs. 63 of 147;
P = .048), and a lengthy procedure (durations >300 minutes,
75% vs. 44.9%; P = .022).
Incisional Site Characteristics
Purulent drainage and erythema were the most common
manifestations of chest and leg infections, respectively (table
2). Chest infections were more likely than leg infections to be
associated with purulent drainage (67.1 % vs. 49.5%; P = .029)
and fever (23.5% vs. 13.4%; P = .002). Leg infections were
more likely to be associated with erythema (61.9% vs. 38.8%;
P = .009) and pain (34.0% vs. 18.8%; P = .019). At diagnosis,
144 wound infections (79.1 %) had at least one of the following
signs or symptoms: purulent drainage, erythema, pain, fever,
or (in chest infections) sternal instability; however, only 15
(8.2%) had the triad of drainage, erythema, and fever. There
was no significant difference between the chest and leg infections with regard to the time to detection of infection.
Microbiology Results
Wound cultures were performed in 83.5% of cases of infection, and 82.2% were positive. Pure cultures most commonly
yielded Staphylococcus aureus (32.9%), coagulase-negative
staphylococci (27.4%), and Enterobacteriaceae (26.0%) (table
3). Polymicrobial infections involved a similar spectrum of
pathogens and frequently involved both gram-positive and
gram-negative organisms (62.3%) or a yeast species and a
bacterium (13.2%). Almost one-quarter of polymicrobial culture specimens were obtained intraoperatively and likely represented true polymicrobial infection, but the remainder were
obtained at the bedside via wound aspiration, with a higher
risk of contamination. Methicillin resistance was documented
in 37.1% of35 S. aureus isolates. Pure culture specimens were
obtained more commonly from chest wounds than from leg
wounds (45 of 85 vs. 28 of 97; P = .002) (table 3). Among
pure culture specimens, coagulase-negative staphylococci and
S. aureus were more commonly isolated from chest wound
specimens (35.6% and 33.3%, respectively), whereas Enterobacteriaceae were more commonly isolated from leg wound
specimens (35.7%). Overall, including pure and polymicrobial
cultures, gram-negative pathogens were more commonly isolated from leg wounds vs. chest wounds (57 of 116 vs. 21 of
83; P = .001).
Table 2. Comparison of signs and symptoms of wound infection,
as related to site (chest vs. leg).
Variable
Sign or symptom, in no.
(%) of infections
Purulent drainage
Erythema
Sternal instability
Fever
Pain
Days to detection, mean
(range)
Chest site
(n = 85)
57
33
22
20
16
(67.1)
(38.8)
(25.9)
(23.5)
(18.8)
19.2 (3-176)
Leg site
(n = 97)
Outcome Analysis
P value
(13.4)
(34.0)
.029
.009
NA
.002
.002
24.1 (3 -125)
NS
48
60
0
13
33
(49.5)
(61.9)
Operative reexploration for debridement occurred in 34
(20.9%) of the 163 patients with wound infections, including
30 with deep chest infections, 3 with superficial chest infections, and 1 with a deep leg infection. Reexploration for debridement was associated with the following factors: chest infection (33 of 78 vs. 1 of 85; P < .001), prior reexploration
for hemorrhage (9 of 20 vs. 25 of 143; P = .005), and smoking
(22 of 81 vs. 12 of 82; P = .049). Flap surgery followed
reexploration in 20 patients (12.3%), including 18 cases of
cm
1996;22 (March)
Table 3.
Wound Infections Following Cardiothoracic Surgery
Microbiology of wound cultures.
No. (%) of infections
Isolate
In pure culture
Staphylococcus aureus
Coagulase-negative staphylococci
Enterobacteriaceae
Yeast species
Pseudomonas aeruginosa
Enterococcus species
Other species
In polymicrobial culture
Enterobacteriaceae
Coagulase-negative staphylococci
Staphylococcus aureus
Enterococcus species
Pseudomonas aeruginosa
Yeast species
Other species
Total
Chest
Leg
73 (100)
24 (32.9)
20 (27.4)
19 (26.0)
4 (5.5)
3 (4.1)
2 (2.7)
1 (1.4)
126 (100)
36 (28.6)
20 (15.9)
18 (14.3)
16 (12.7)
14 (11.1)
7 (5.6)
15 (11.9)
45 (100)
15 (33.3)
16 (35.6)
9 (20.0)
3 (6.7)
0
1 (2.2)
1 (2.2)
38 (100)
7 (18.4)
12 (31.6)
4 (10.5)
4 (10.5)
1 (2.6)
3 (7.9)
7 (18.4)
28 (100)
9 (32.1)
4 (14.3)
10 (35.7)
1 (3.6)
3 (10.7)
1 (3.6)
0
88 (100)
29 (33.0)
8 (9.1)
14 (15.9)
12 (13.6)
13 (14.8)
4 (4.5)
8 (9.1)
deep chest infection and 1 each of superficial chest and deep
leg infection. Flap surgery was associated with chest infection
(19 of 78 vs. 1 of 85; P < .001) and obesity (9 of 39 vs. 11
of 124; P = .018). Seven patients (4.3%) died, and wound
infections contributed directly to the fatal outcome of five (four
deep chest and one deep leg infection). Death was associated
with reexploration for hemmorrhage (4 of 20 vs. 3 of 143;
P = .005). The mean length of stay was 34.9 days (range, 6283 days) overall and was similar for chest infections and leg
infections (37.0 days and 30.0 days, respectively). Patients with
deep chest infections had worse outcomes compared to those
for other infected patients, including more frequent reexploration and/or flap surgery (31 of 36 vs. 5 of 127; P < .001), and
the mortality among them was greater (4 of 36 vs. 3 of 127;
P = .043).
Discussion
We identified a wound infection rate of 11.7% during 30
months of active surveillance of cardiothoracic surgery patients. The recency of surveillance suggests that our results
reflect the infection risk at our institution in the modem era of
cardiothoracic surgery. Our rates may reflect the risks at similar
tertiary care institutions but are not necessarily applicable to
nonreferral centers, given the potential differences in the patient
populations. Because of the increased pressure for early discharge and the incomplete nature of follow-up, our wound
infection rate may still underestimate the true risk [1, 2, 4, 5,
23]. Implementation of formal postdischarge surveillance will
be required to establish the true risk of wound infection in
cardiothoracic surgery and its impact on patient morbidity and
mortality [5, 23].
427
Through active surveillance, we recognized that untimely
antibiotic prophylaxis and unnecessary chest-hair shaving were
common in the cardiothoracic surgery department. Since the
time of our study, we have initiated infusion of prophylactic
antibiotics by anesthesiologists in the holding area prior to
surgery, and this has increased the percentage of patients receiving timely prophylaxis to nearly 95%. We also have eliminated routine shaving of chests prior to surgery, but clipping
is used if necessary. Prospective evaluation of both of these
interventions will be needed to demonstrate efficacy in reducing
wound infections.
Investigators of prior series defined deep chest infection rates
of 0.5%-5.0% but failed to analyze the rates of superficial
chest infection and superficial and deep leg infection [5 -12,
23 - 31]. Kaiser et al. documented the impact of both chest and
leg wound infections on patients' outcome and hospital charges
in 1987 [47], and the CDC has focused additional attention on
site-specific rates [21]. Investigators of series of superficial and
deep infections have reported rates similar to ours [14, 17,
45]. Active surveillance, utilization of standard definitions, and
reduction of the influence of surgeons' self-reporting bias may
increase the reported rates of wound infections [1,2,8, 11, 13,
18, 19]. Greater comorbidity, acuity of illness, and/or case
complexity in cardiothoracic surgery departments at tertiary
care centers may also contribute to higher rates [8, 13, 16].
Despite the increasing complexity of CABG vs. valve vs.
combined CABG/valve surgery, we noted consistent rates of
superficial chest (3.1%-4.0%) and deep chest (0.8%-2.5%)
infections among the three procedures, as noted in other series
[6, 7, 9, 12]. However, following saphenous vein harvesting,
leg infection complicated combined CABG/valve surgery more
frequently than it did CABG surgery, accounting for the difference in total infection rates (18.3% vs. 11.2%) between the
two procedures. The greater mean age of patients undergoing
combined CABG/valve surgery may be partially responsible.
In addition, the extended mean duration of combined CABG/
valve surgery may have increased the risk of intraoperative
contamination.
The pathogenesis of chest and leg wound infections is not
fully understood and may be distinct for each site [13, 41,
42]. We and others have identified gram-negative infections
(particularly those due to Enterobacteriaceae) more frequently
involving the leg [13, 17,42]. Assuming intraoperative wound
contamination is a prerequisite for the majority of infections
at either site, it is possible that the patient's fecal flora represent
the primary pathogens for the development of leg infections
because of greater intraoperative contamination of the leg
wound [13, 17,42]. This suggests that additional preoperative
strategies for the prevention of leg infections may be necessary,
including a longer leg-skin antibacterial scrub, use of alternative skin antibacterial agents, and perhaps gastrointestinal decontamination.
Diagnosis of wound infection following cardiothoracic surgery remains difficult and requires increased clinical suspicion
428
L' Ecuyer et al.
during the first 14 days postoperatively, when most infections
present [6, 8, 9, 13, 48]. It may be difficult to distinguish the
signs of an infected wound from those of a poorly healing,
noninfected wound. We found the combination of drainage,
erythema, and fever to be uncommon, and infections may be
missed if clinicians rely on the presence of these three signs.
Widespread utilization of the NNIS criteria may improve detection of wound infections and allow for improved interhospital
comparisons of infection rates through standardization [21].
The occurrence of wound infections due to coagulase-negative staphylococci, gram-negative organisms, and fungi may
be increasing in cardiothoracic surgery [6-10, 13, 32, 41-43,
49]. We noted coagulase-negative staphylococci in 35.6% of
the pure chest-specimen cultures, gram-negative organisms in
35.7% of the pure leg-specimen cultures, and fungi in 5.5% of
the pure cultures overall. Infection at either site may involve
gram-positive, gram-negative, or mixed (albeit contaminating)
pathogens, so broad empirical antibiotic therapy must be considered for both sites, pending culture data [5-8, 13]. Antifungal therapy should be considered when patients are unresponsive to standard antibiotic regimens [7, 9, 13, 32, 49].
In our series combined chest and leg infections were associated with similarly prolonged hospital stays, in comparison
with the average stay in 1993 of 9.3 days for uncomplicated
cardiothoracic surgery, a finding emphasizing that both contribute significantly to excessive morbidity following such surgery.
The mortality associated with deep chest infection (11.1 %) in
our series compares favorably with recent series noting 10%.,40% mortality [5-10, 12, 13,28]. Overall, we noted low mortality (4.3%) among patients with wound infections, despite
the high frequency of comorbid conditions and delayed diagnosis, as well as the extensive nature of deep chest infections.
Infection-related mortality was not limited to patients with deep
chest involvement, as a deep leg wound infection contributed to
one patient's death. With prospective payment patterns, wound
infections result in higher hospital costs, with net losses overall
[5, 14, 15, 50]. Thus, prevention of both chest and leg wound
infections should be a priority in cardiothoracic surgery.
Prospective studies in cardiothoracic surgery are needed to
validate the efficacy of generic infection-control strategies (including reporting of infection rates to surgeons) and more specific interventions (such as timely antibiotic prophylaxis and
elimination of chest-hair shaving). In addition, case-control
investigations of wound infections at both chest and leg sites
will be required to discriminate risks factors for each and to
develop site-specific risk indices for future prevention efforts.
Finally, documentation of resource utilization associated with
all wound infections in cardiothoracic surgery will help focus
attention on these complications.
References
1. Olson MM, Lee JT Jr. Continuous, 1O-year wound infection surveillance:
results, advantages, and unanswered questions. Arch Surg 1990;
125:794-803.
cm
1996; 22 (March)
2. Nichols RL. Surgical wound infection. Am J Med 1991; 91(suppI3B):54S64S.
3. Ehrenkranz NJ, Meakins JL. Surgical infections. In: Bennett N, Brachman
PS, Sanford JP, eds. Hospital infections. 3rd ed. Boston: Little, Brown,
1992;685-710.
4. Sawyer RG, Pruett TL. Wound infections. Surg Clin North Am
1994;74:519-36.
5. Loop FD, Lytle BW, Cosgrove DM, et al. Sternal wound complications
after isolated coronary artery bypass grafting: early and late mortality,
morbidity, and cost of care. Ann Thorac Surg 1990;49:179-87.
6. SaIT MG, Gott VL, Townsend TR. Mediastinal infection after cardiac
surgery. Ann Thorac Surg 1984;38:415-23.
7. Culliford AT, Cunningham IN Jr, ZeffRH, Isom OW, Teiko P, Spencer
FC. Sternal and costochondral infections following open-heart surgery:
a review of 2,594 cases. J Thorac Cardiovasc Surg 1976; 72:714-26.
8. Bar DH, Rose RM, Modlin JF, Weintraub R, Friedland GH. Mediastinitis
after cardiovascular surgery. Rev Infect Dis 1983;5:885-97.
9. Grossi EA, Culliford AT, Krieger KH, et al. A survey of 77 major infectious complications of median sternotomy: a review of 7,949 consecutive operative procedures. Ann Thorac Surg 1985;40:214-23.
10. Cheung EH, Craver JM, Jones EL, Murphy DA, Hatcher CR Jr, Guyton
RA. Mediastinitis after cardiac valve operations: impact upon survival.
J Thorac Cardiovasc Surg 1985;90:517-22.
11. Newman LS, Szczukowski LC, Bain RP, Perlino CA. Suppurative mediastinitis after open heart surgery: a case control study of risk factors.
Chest 1988;94:546-53.
12. Demmy TL, Park SB, Liebler GA, et al. Recent experience with major
sternal wound complications. Ann Thorac Surg 1990;49:458-62.
13. Greenblatt J, Fischer RA. Complications of cardiac surgery: infections.
In: Kotler MN, Alfieri A, eds. Cardiac and noncardiac complications
of open heart surgery: prevention, diagnosis, and treatment. Mount
Kisco, New York: Futura, 1992:145-76.
14. Nelson RM, Dries DJ. Economic implications of infection in cardiac surgery. Ann Thorac Surg 1986; 42:240-6.
15. Boyce JM, Potter-Bynoe G, Dziobek L. Hospital reimbursement patterns
among patients with surgical wound infections following open heart
surgery. Infect Control Hosp Epidemiol 1990; 11:89-93.
16. Taylor GJ, Mikell FL, Moses HW, et al. Determinants of hospital charges
for coronary artery bypass surgery: the economic consequences of postoperative complications. Am J CardioI1990;65:309-13.
17. Sellick JA Jr, Stelmach M, Mylotte JM. Surveillance of surgical wound
infections following open heart surgery. Infect Control Hosp Epidemiol
1991; 12:591-6.
18. Haley RW, Culver DH, White JW, et al. The efficacy of infection surveillance and control programs in preventing nosocomial infections in US
hospitals. Am J Epidemiol1985; 121:182-205.
19. Cruse PJE, Foord R. The epidemiology of wound infection: a 10-year
prospective study of 62,939 wounds. Surg Clin North Am 1980; 60:2740.
20. Haley RW, Culver DH, Morgan WM, White JW, Emori TG, Hooton TM.
Identifying patients at high risk of surgical wound infection. A simple
multivariate index of patient susceptibility and wound contamination.
Am J Epidemiol 1985; 121 :206-15.
21. Culver DH, Horan TC, Gaynes RP, et al. Surgical wound infection rates
by wound class, operative procedure, and patient risk index. Am J Med
1991;91(suppI3B):152S-7S.
22. Roy MC, Herwaldt LA, Embrey R, Kuhns K, Wenzel RP, Perl TM. Does
the NNIS risk index (NRI) predict which patients develop wound infection (SWI) after cardiothoracic (CT) surgery? [abstract no. J209]. In:
Program and abstracts of the 34th Interscience Conference on Antimicrobial Agents and Chemotherapy. Washington, DC: American Society
for Microbiology, 1994:196.
23. Breyer RH, Mills SA, Hudspeth AS, Johnston FR, Cordell AR. A prospective study of sternal wound complications. Ann Thorac Surg
1984; 37:412-6.
cm
1996;22 (March)
Wound Infections Following Cardiothoracic Surgery
24. Cosgrove DM, Lytle BW, Loop FD, et al. Does bilateral internal mammary
artery grafting increase surgical risk? J Thorac Cardiovasc Surg
1988; 95:850-6.
25. Kouchoukos NT, Wareing TH, Murphy SF, Pe1ate C, Marshal WG Jr.
Risks of bilateral internal mammary artery bypass grafting. Ann Thorac
Surg 1990;49:210-9.
26. Nishida H, Grooters RK, Merkley DF, Thieman KC, Soltanzadeh H. Postoperative mediastinitis: a comparison of two electrocautery techniques
on presternal soft tissues. J Thorac Cardiovasc Surg 1990;99:969-76.
27. Gaynes R, Marosok R, Mowry-Hanley J, et al. Mediastinitis following
coronary artery bypass surgery: a 3-year review. J Infect Dis
1991; 163:117-21.
28. Grossi EA, Esposito R, Harris LJ, et al. Sternal wound infections and use
of internal mammary artery grafts. J Thorac Cardiovasc Surg
1991; 102:342-7.
29. Ehrenkranz NJ, Pfaff SJ. Mediastinitis complicating cardiac operations:
evidence of postoperative causation. Rev Infect Dis 1991; 13:803-14.
30. Ko W, Lazenby WD, Zelano JA, Isom OW, Krieger KH. Effects of shaving
methods and intraoperative irrigation on suppurative mediastinitis after
bypass operations. Ann Thorac Surg 1992;53:301-5.
31. He GW, Ryan WH, AcuffTE, et al. Risk factors for operative mortality and
sternal wound infection in bilateral internal mammary artery grafting. J
Thorac Cardiovasc Surg 1994; 107:196-202.
32. Richet HM, McNeil MM, Davis BJ, et al. Aspergillus fumigatus sternal
wound infections in patients undergoing open heart surgery. Am J Epidemioll992; 135:48-58.
33. Fong IW, Baker CB, McKee DC. The value of prophylactic antibiotics in
aorta-coronary bypass operations: a double-blind randomized trial. J
Thorac Cardiovasc Surg 1979; 78:908-13.
34. Austin TW, Coles JC, Burnett R, Goldbach M. Aortocoronary bypass
procedures and sternotomy infections: a study of antistaphylococcal
prophylaxis. Can J Surg 1980;23:483-5.
35. Conklin CM, Gray RJ, Neilson D, Wong P, Tomita DK, Madoff JM.
Determinants ofwound infection incidence after isolated coronary artery
bypass surgery in patients randomized to receive prophylactic cefuroxime or cefazolin. Ann Thorac Surg 1988; 46: 172-7.
36. Doebbeling BN, Pfaller MA, Kuhns KR, Massanari RM, Behrendt DM,
Wenzel RP. Cardiovascular surgery prophylaxis. A randomized, controlled comparison of cefazolin and cefuroxime. J Thorac Cardiovasc
Surg 1990;99:981-9.
37. Goldmann DA, Hopkins CC, Karchmer AW, et al. Cephalothin prophylaxis in cardiac valve surgery: a prospective, double-blind comparison
of two-day and six-day regimens. J Thorac Cardiovasc Surg
1977; 73:470-9.
429
38. Nagachinta T, Stephens M, Reitz B, Polk BF. Risk factors for surgical
wound infection following cardiac surgery. J Infect Dis 1987; 156:96773.
39. Lillienfeld DE, Vlahov D, Tenney JH, McLaughlin JS. Obesity and diabetes as risk factors for postoperative wound infections after cardiac surgery. Am J Infect Control 1988; 16:3-6.
40. Sethi GK, Copeland JG, Moritz T, Henderson W, Zadina K, Goldman S.
Comparison of postoperative complications between saphenous vein
and lMA grafts to left anterior descending coronary artery. Ann Thorac
Surg 1991;51:733-8.
41. Wells FC, Newsom SWB, Rowlands C. Wound infection in cardiothoracic
surgery. Lancet 1983; 1:1209-10.
42. Farrington M, Webster M, Fenn A, Phillips I. Study of cardiothoracic
wound infection at St. Thomas' Hospital. Br J Surg 1985; 72:759-62.
43. Hazelrigg SR, Wellons HA, Schneider JA, Kolm P. Wound complications
after median sternotomy: relationship to internal mammary grafting. J
Thorac Cardiovasc Surg 1989;98:1096-9.
44. Nishida H, Grooters RK, Soltanzadeh H, Thieman KC, Schneider RF,
Kim WP. Discriminate use of electrocautery on the median sternotomy
incision: a 0.16% wound infection rate. J Thorac Cardiovasc Surg
1991; 101:488-94.
45. Ridgway EJ, Wilson AP, Kelsey MC. Preoperative screening cultures in
the identification of staphylococci causing wound and valvular infections in cardiac surgery. J Hosp Infect 1990; 15:55-63.
46. Kahn M, Steib S, Fraser V, Dunagan W. Expert system for culture-based
infection control surveillance. In: Proceedings of the Annual Symposium on Computer Applications in Medical Care. New York: Institute
of Electrical and Electronics Engineers, 1993:171-5.
47. Kaiser AB, Petracek MR, Lea JW IV, et al. Efficacy of cefazolin, cefamandole, and gentamicin as prophylactic agents in cardiac surgery: results
of a prospective, randomized, double-blind trial in 1030 patients. Ann
Surg 1987;206:791-7.
48. Kohman LJ, Coleman MJ, Parker FB Jr. Bacteremia and sternal infection
after coronary artery bypass grafting. Ann Thorac Surg 1990; 49:
454-7.
49. Barzaghi N, Emmi V, Mencherini S, Minzioni G, Marone P, Minoli L.
Sternal osteomyelitis due to Aspergillus fumigatus after cardiac surgery.
Chest 1994; 105:1275-7.
50. Haley RW, White JW, Culver DH, Hughes JM. The financial incentive
for hospitals to prevent nosocomial infections under the prospective
payment system: an empirical determination from a nationally representative sample. JAMA 1987;257:1611-4.