Surveillance of postoperative infections in thoracic surgery

Nosocomial infections and antibiotic resistance pattern in open-heart surgery patients at Imam Ali Hospital in Kermanshah, Iran

Background: Patients undergoing open heart surgery have a relatively high risk of acquiring nosocomial infections. The development of antibiotic-resistant infections is associated with prolonged hospital stays and mortalities.

Objectives: The present study was conducted to investigate nosocomial infections and the antibiotic resistance pattern in bacteria causing these infections in open heart surgery patients at Imam Ali Hospital in Kermanshah in the west of Iran over a 4-year period from March 2011 to March 2014.

Materials and methods: The present cross-sectional study was conducted on 135 cases of nosocomial infection among open heart surgery patients. The demographic characteristics and the risk factors of each case of infection were recorded. The antibiotic susceptibility test was carried out using the Minimum Inhibitory Concentration (MIC) method based on the Clinical and Laboratory Standards Institute (CLSI) protocol. The data collected were then analyzed in SPSS-16.

Results: Out of the 6,000 patients who underwent open heart surgery during this 4-year period at the selected hospital, nosocomial infections developed in 135 patients (2.25%), 59.3% of whom were female and 40.7% male. Surgery site infection (SSI), pneumonia (PNEU), urinary tract infection (UTI) and blood stream infection (BSI) affected 52.6%, 37%, 9.6% and 0.8% of the cases, respectively. E.coli, Klebsiella spp. and S. aureus were the most common bacteria causing the nosocomial infections. E. coli was most frequently resistant to imipenem (23.3%) Klebsiella spp. to gentamicin (38.5%) S. aureus to co-trimoxazole (54.2%).

Conclusion: SSI had a high prevalence in this study. Further studies should therefore be conducted to examine the risk factors associated with SSI in open heart surgery. Various studies have shown that antibiotic resistance patterns are different in different regions. Finding a definitive treatment therefore requires an antibiogram.

Molecular analysis of the coagulase gene in clinical and nasal carrier isolates of methicillin-resistant Staphylococcus aureus by restriction fragment length polymorphism

OBJECTIVES

The coagulase enzyme, encoded by the coa gene, is an important virulence factor of Staphylococcus aureus and can be used for typing of S. aureus isolates. In this study, coa gene typing was used to study the epidemiology of S. aureus at a university hospital in Hamadān (Iran).

METHODS

A total of 200 S. aureus strains were analysed, among which 150 were isolated from clinical samples and 50 were from nasal swab specimens of carriers. Methicillin resistance was confirmed by presence of the mecA gene by PCR. For polymorphism analysis, the coa gene was amplified by PCR and the products were subjected to restriction digestion using the enzyme AluI.

RESULTS

Amplification of the coa gene produced five classes of bands based on size, ranging from 300bp to 800bp. The 600-bp amplicon included coa 3 genotype predominated in S. aureus isolated from clinical and carrier specimens (150/200; 75.0%). AluI digestion of the PCR products produced eight distinct restriction fragment length polymorphism (RFLP) patterns, designated coa 1-8. The results showed that the 700-bp and 800-bp amplicons formed two (coa 4a and 4b) and three (coa 5a, 5b and 5c) patterns following AluI digestion, respectively, whereas the 300-, 500- and 600-bp fragments generated unique patterns designated coa 1, coa 2 and coa 3, respectively.

CONCLUSIONS

This study performed coagulase typing, a technique used to determine the molecular epidemiology of S. aureus clinical isolates. coa gene amplification has been considered a simple and accurate method for typing of S. aureus.

Early removal of urinary catheter after surgery requiring thoracic epidural: a prospective trial

OBJECTIVES

To prevent urinary retention, urinary catheters commonly are removed only after thoracic epidural discontinuation after thoracotomy. However, prolonged catheterization increases the risk of infection. The purpose of this study was to determine the rates of urinary retention and catheter-associated infection after early catheter removal.

DESIGN

This study described a prospective trial instituting an early urinary catheter removal protocol compared with a historic control group of patients.

SETTING

The protocol was instituted at a single, academic thoracic surgery unit.

PARTICIPANTS

The study group was comprised of patients undergoing surgery requiring thoracotomy who received an intraoperative epidural for postoperative pain control.

INTERVENTIONS

An early urinary catheter removal protocol was instituted prospectively, with all catheters removed on or before postoperative day 2. Urinary retention was determined by bladder ultrasound and treated with recatheterization.

MEASUREMENTS AND MAIN RESULTS

The primary outcomes were urinary retention rate, defined as bladder volume>400 mL, and urinary tract infection rate. Results were compared with a retrospective cohort of 210 consecutive patients who underwent surgery before protocol initiation. Among the 101 prospectively enrolled patients, urinary retention rate was higher (26.7% v 12.4%, p = 0.003), while urinary tract infection rate improved moderately (1% v 3.8%, p = 0.280).

CONCLUSIONS

Early removal of urinary catheters with thoracic epidurals in place is associated with a high incidence of urinary retention. However, an early catheter removal protocol may play a role in a multifaceted approach to reducing the incidence of catheter-associated urinary tract infections.

Reduction of Surgical-Site Infections in Cardiothoracic Surgery by Elimination of Nasal Carriage ofStaphylococcus aureus

Objective:

To test the hypothesis that perioperative elimination of nasal carriage ofStaphylococcus aureususing mupirocin nasal ointment reduces the surgical-site infection (SSI) rate in cardiothoracic surgery.

Design:

Unblinded intervention trial with historical controls.

Setting:

A university hospital, tertiary referral center for cardiothoracic surgery.

Patients:

Consecutive patients undergoing cardiothoracic surgery between August 1, 1989, and February 1, 1991 (historical control group), and between March 1, 1991, and August 1, 1992 (intervention group).

Results:

The historical control group consisted of 928 patients and the intervention group of 868, of whom 752 actually were treated. The 116 patients who were unintentionally not treated were considered as a concurrent control group. In the intention-to-treat analysis, a significant reduction in SSI rate was observed after the intervention (historical-control group 7.3% and intervention group 2.8%;P<.0001). The SSI rate in the concurrent control group was significantly higher than in the treated group (7.8% and 2.0%, respectively;P=.0023). Resistance ofS aureusto mupirocin was not observed.

Conclusion:

The results of this study indicate that perioperative elimination of nasal carriage using mupirocin nasal ointment significantly reduces the SSI rate in cardiothoracic surgery patients and warrants a prospective, randomized, placebo-controlled efficacy trial. This preventive measure may be beneficial in other categories of surgical patients as well.

Closed incision management with negative pressure wound therapy

Post-sternotomy mediastinitis is the most severe surgical site infection after sternotomy with an incidence between 1-4% related to the patient co-morbidity. This complication will increase morbidity and mortality and may also have an economic impact. There are guidelines to prevent surgical site infections; however, age and co-morbidities increase and therefore it is important to develop new tools to improve wound healing. This manuscript will give an overview of a new concept using negative pressure wound therapy over a closed incision (so-called, closed incision management) after surgery and will include the principles of negative pressure wound therapy and the positively applied mechanical forces as a permutation of Wolff's law. The use and indication of this therapy is supported by experimental studies divided into physiological and biomechanical property studies. Finally, an overview of clinical studies is given based on the evidence rating scale for therapeutic studies.

Postoperative differences between colonization and infection after pediatric cardiac surgery-a propensity matched analysis

Background

The objective of this study was to identify the postoperative risk factors associated with the conversion of colonization to postoperative infection in pediatric patients undergoing cardiac surgery.

Methods

Following approval from the Institutional Review Board, patient demographics, co-morbidities, surgery details, transfusion requirements, inotropic infusions, laboratory parameters and positive microbial results were recorded during the hospital stay, and the patients were divided into two groups: patients with clinical signs of infection and patients with only positive cultures but without infection during the postoperative period. Using propensity scores, 141 patients with infection were matched to 141 patients with positive microbial cultures but without signs of infection. Our database consisted of 1665 consecutive pediatric patients who underwent cardiac surgery between January 2004 and December 2008 at a single center. The association between the patient group with infection and the group with colonization was analyzed after propensity score matching of the perioperative variables.

Results

179 patients (9.3%) had infection, and 253 patients (15.2%) had colonization. The occurrence of Gram-positive species was significantly greater in the colonization group (p = 0.004). The C-reactive protein levels on the first and second postoperative days were significantly greater in the infection group (p = 0.02 and p = 0.05, respectively). The sum of all the positive cultures obtained during the postoperative period was greater in the infection group compared to the colonization group (p = 0.02). The length of the intensive care unit stay (p < 0.001) was significantly longer in the infection group compared to the control group.

Conclusions

Based on our results, we uncovered independent relationships between the conversion of colonization to infection regarding positive S. aureus and bloodstream results, as well as significant differences between the two groups regarding postoperative C-reactive protein levels and white blood cell counts.

Primary closure using Redon drains vs vacuum-assisted closure in post-sternotomy mediastinitis

OBJECTIVES

Vacuum-assisted closure (VAC) is a commonly used therapy for the treatment of post-sternotomy mediastinitis. Primary closure of the sternum with high vacuum suction using Redon drains is an alternative that may reduce hospital stay. The aim of this study was to describe for the first time, the results of VAC compared with Redon drainage.

METHODS

We performed a retrospective analysis of 132 patients undergoing VAC (n = 89) or primary closure of the sternum with Redon drains (n = 43) as treatment for post-sternotomy mediastinitis between January 2000 and January 2011. Patient characteristics, risk factors and procedure-related variables were analysed. Duration of therapy, treatment failure, hospital stay and mortality as well as C-reactive protein and blood leucocyte counts on admission and at various time intervals during hospital stay were determined.

RESULTS

In-hospital mortality was 12.5% in the VAC group compared with 14% in the Redon group (P = 0.96). Treatment failure in the VAC and Redon groups occurred in 28 and 23% of the patients, respectively (P = 0.68). Intensive-care stay in the VAC group was 6.8 ± 14.4 days, and 4.8 ± 10.1 days in the Redon group (P = 0.99). Hospitalization in the VAC group was 74 ± 61 days and in the Redon group, 45 ± 38 days (P = 0.0001).

CONCLUSIONS

Primary closure using high vacuum suction drains is a safe and feasible treatment modality for post-sternotomy mediastinitis. It reduces hospital stay when compared with VAC therapy, without compromising mortality.

Randomized clinical trial comparing two options for postoperative incisional care to prevent poststernotomy surgical site infections

Surgical site infection (SSI) remains an important complication of cardiac surgery. Prevention is important, as SSI is associated with high mortality and morbidity rates. Incisional care is an important daily issue for surgeons. However, there is still scant scientific evidence on which guidelines can be based. A randomized clinical trial was performed to compare two options for postoperative incisional care. Patients undergoing sternotomy for cardiothoracic surgery were eligible. To protect an incision from exogenous contamination or direct inoculation by endogenous pathogens, the study group received an adhesive drape, impermeable to water and air. The control group was treated with a water- and air-permeable absorbent dressing. Primary outcome measure was SSI. Between March 2003 and January 2005, 1,185 patients were included. Both groups were comparable for base-line characteristics. No significant difference was found in the incidence of sternal SSI between groups (2.6 vs. 3.3%). In our study, an incisional-care program using a sterile, impermeable adhesive drape did not perform better than an absorbent dressing in reducing SSI after cardiothoracic surgery. In our view, future studies in the field of prevention of SSI should concentrate on other areas of interest.

Impact of treating Staphylococcus aureus nasal carriers on wound infections in cardiac surgery

Staphylococcus aureus is a common cause of postoperative wound infections, and nasal colonization by this organism is an important factor in the development of infections. Treatment with mupirocin can eradicate the organism in the short term, and prophylactic treatment of colonized patients may prevent postoperative S. aureus infections. A double-blind, randomized, placebo-controlled trial was performed to determine whether nasal mupirocin administered pre-operatively to S. aureus carriers reduces the rates of sternal and leg wound infections after cardiac surgery. The study enrolled 263 patients with nasal S. aureus undergoing elective cardiac surgery at St. Michael's Hospital, Toronto, Canada. Patients were assessed for infections in the immediate postoperative period and two months later. Two hundred and fifty-seven patients were included in the intention-to-treat analysis and re-analysed according to the actual treatment applied. Wound infections occurred in 17 (13.5%) mupirocin recipients and 11 (9.1%) placebo recipients (P=0.319), with seven (5.4%) and six (4.7%) sternal infections, respectively. Two (1.6%) wound infections were acquired postoperatively in the mupirocin group, neither of which were caused by S. aureus. The placebo group had three (2.4%) nosocomial wound infections, with two (1.6%) S. aureus bacteraemias (P=0.243). Among patients receiving mupirocin, 106 (81.5%) cleared S. aureus compared with 59 (46.5%) patients receiving placebo (P<0.0001). There was no significant difference between intention-to-treat and actual treatment groups. Prophylactic intranasal mupirocin administered to S. aureus carriers did not reduce the rates of overall surgical site infections by S. aureus, and only showed a trend towards decreased incidence of nosocomial S. aureus infections.

Analysis of risk factors for sternal surgical site infection: emphasizing the appropriate ventilation of the operating theaters

OBJECTIVE

To determine the incidence of and identify risk factors for sternal surgical site infection (SSI).

DESIGN

Prospective cohort study. Data on potential risk factors, including the type of operating theater and infection data, were collected prospectively and analyzed by multivariate analysis.

SETTING

Siyami Ersek Thoracic and Cardiovascular Surgery Hospital, a 700-bed teaching hospital and the largest center for cardiac surgery in Turkey. The cardiothoracic unit performs approximately 3,000 cardiac operations per year.

PATIENTS

All adult patients who underwent cardiac surgery with sternotomy between January 14, 2002, and July 1, 2002, and who survived at least 4 days after surgery were included in the study.

RESULTS

Potential risk factor data were complete for 991 patients. There was sternal SSI in 41 patients (4.1%). Female sex, diabetes mellitus, operation performed in the older operating theaters, and duration of procedure exceeding 5 hours were identified as independent risk factors for sternal SSI.

CONCLUSIONS

Female and diabetic patients are at higher risk for sternal SSI and should be followed up carefully after cardiac surgery to prevent the development of sternal SSI. Reducing the duration of surgery could reduce the rate of postoperative sternal SSI. The operating theater environment may have an important role in the pathogenesis of sternal SSI, and appropriate ventilation of the operating theaters would be critical in the prevention of sternal SSI.

Predictors and Outcomes of Sternal Wound Complications in Patients after Coronary Artery Bypass Graft Surgery

We sought to assess predictors and outcomes of sternal wound complications in patients after coronary artery bypass grafting (CABG). A nested, case-control study from a 10-year hospitalization cohort with prospective data collection was conducted. Included in the cohort were patients age 18 and above undergoing CABG surgery between March 1997 and July 2003 (n = 7889). Patients who underwent any surgery other CABG were excluded. Cases were matched to controls 1:3 on year of surgery. Cases were CABG patients with sternal wound complications, which was defined as requiring antibiotics and/or topical treatment, requiring extra nursing care, dehiscence, or requiring surgical intervention (n = 89). Controls were CABG patients without sternal wound complications (n = 267). The study examined 29 risk factors and 10 outcome variables. Univariate analysis on the risk factors revealed 10 significant risk factors. Logistic regression analysis was conducted and the risk factors that significantly predicted sternal wound complications after CABG surgery included older age (odds ratio [OR] = 0.85, 95% confidence interval [CI] 0.808–0.892), previous CABG surgery (OR = 3.9, 95% CI 1.03–15.37), and in class three or four of the New York Heart Association functional class (OR = 2.8, 95% CI 1.27–6.12). There was a significant difference between CABG patients with and without sternal wound complications on nine outcome variables. Of the 29 predictors of post-CABG sternal wound infections being examined, 10 proved to be significant. Further analysis demonstrated only three variables that significantly predicted sternal wound complications. Older age, previous CABG surgery, and class three or four of the New York Heart Association functional class predispose CABG patients to sternal wound infections.

Risk control of surgical site infection after cardiothoracic surgery

The purpose of this prospective study was to investigate whether a risk control programme based on risk assessment, new treatment modalities and the presence of a surveillance programme reduces the incidence of surgical site infections (SSI). Between January 2001 and December 2003, 167 patients were treated for a total of 183 SSIs. Data were collected on pre-operative risk factors, intra-operative data and postoperative recovery, including complications, infecting organisms, SSI treatment techniques and length of hospital stay. In this series, the total incidence of SSI was 5.6%. The mean age of affected patients was 65.1 years with a range of 20-87 years. Mean intensive care and hospital stay for SSI was 3.6 days and 18.8 days, respectively. Total mortality was 4.8%. Many risk factors were encountered, some of which were associated with a high morbidity. The majority of SSIs were treated by topical negative pressure therapy (N=81), which gave few side-effects and good clinical results. After starting the surveillance programme, a steady decline in prevalence was observed from 8.9% to 3.9%. This series adds to the evidence that SSI after cardiothoracic surgery is a major but mainly preventable cause of morbidity and mortality. Risk factor assessment, application of novel treatment modalities and an adequate surveillance system all increased patient safety.

Poststernotomy mediastinitis: comparison of two treatment modalities

Poststernotomy mediastinitis (PM) is a serious and potentially lethal condition with an overall incidence varying from 0.4-5%. There is little consensus on the ideal management of PM. The aim of this retrospective study was to investigate the effectiveness of topical negative pressure (TNP) therapy vs. traditional closed drainage techniques (CDT) as a treatment modality for PM. We reviewed the data of 10,467 patients who underwent median sternotomy between 1 January 1992 and 31 December 2003. During this period 63 patients were treated for PM. Twenty-nine of these patients were treated with TNP and 34 with conventional CDT. Primary points of interest were: treatment modalities, mortality, surgical site infection recurrence and, duration of therapy and hospital stay. In this series, the total incidence of poststernotomy mediastinitis was 0.6% with high morbidity rates. In the TNP group, lower rates of recurring infection, therapeutic failure and fewer defects at discharge were seen (P<0.05). In conclusion, the results of our series add further data to the knowledge that PM is an important cause of morbidity and mortality. TNP is a safe and adequate treatment modality for treating PM.

Nosocomial infection after lung surgery: incidence and risk factors

STUDY OBJECTIVES

To assess the incidence and risk factors for nosocomial infection after lung surgery.

DESIGN

Prospective cohort study.

SETTING

Service of thoracic surgery of an acute-care teaching hospital in Santander, Spain.

PATIENTS

Between June 1, 1999, and January 31, 2001, all consecutive patients undergoing lung surgery were prospectively followed up for 1 month after discharge from the hospital to assess the development of nosocomial infection, the primary outcome of the study.

INTERVENTIONS

During the hospitalization period, patients were visited on a daily basis. Postdischarge surveillance was based on visits to the surgeon.

MEASUREMENTS AND RESULTS

We studied 295 patients (84% men; mean age, 60.9 years), 89% of whom underwent resection operations. Ninety episodes of nosocomial infection were diagnosed in 76 patients, including pneumonia (n = 10), lower respiratory tract infection (n = 47), wound infection (n = 16; one third were detected after hospital discharge), urinary tract infection (n = 9), and bacteremia (n = 8; three fourths were catheter-related bacteremia). Twenty patients had severe infections (pneumonia or empyema), with a mortality rate of 60%. COPD (adjusted odds ratio [OR], 2.70; 95% confidence interval [CI], 1.52 to 4.84), duration of surgery with an increased risk for each additional minute (Mantel-Haenzel chi(2) test for trend, p = 0.037), and ICU admission (OR, 3.69; 95% CI, 1.94 to 7.06) were independent risk factors for nosocomial infection. The use of an epidural catheter was a protective factor (OR, 0.45; 95% CI, 0.22 to 0.95). There were no differences according to the use of amoxicillin/clavulanate or cefotaxime for surgical prophylaxis.

CONCLUSIONS

Nosocomial infections are common after lung surgery. One third of wound infections were detected after hospital discharge. The profile of a high-risk patient includes COPD as underlying disease, prolonged operative time, and postoperative ICU admission.

Surveillance for hospital-acquired infections on surgical wards in a Dutch university hospital

OBJECTIVES

To determine incidence rates of hospital-acquired infections and to develop preventive measures to reduce the risk of hospital-acquired infections.

METHODS

Prospective surveillance for hospital-acquired infections was performed during a 5-year period in the wards housing general and vascular, thoracic, orthopedic, and general gynecologic and gynecologic-oncologic surgery of the University Medical Center Utrecht, the Netherlands. Data were collected from patients with and without infections, using criteria of the Centers for Disease Control and Prevention.

RESULTS

The infection control team recorded 648 hospital-acquired infections affecting 550 (14%) of 3,845 patients. The incidence density was 17.8 per 1,000 patient-days. Patients with hospital-acquired infections were hospitalized for 19.8 days versus 7.7 days for patients without hospital-acquired infections. Prolongation of stay among patients with hospital-acquired infections may have resulted in 664 fewer admissions due to unavailable beds. Different specialties were associated with different infection rates at different sites, requiring a tailor-made approach. Interventions were recommended for respiratory tract infections in the thoracic surgery ward and for surgical-site infections in the orthopedic and gynecologic surgery wards.

CONCLUSIONS

Surveillance in four surgical wards showed that each had its own prominent infection, risk factors, and indications for specific recommendations. Because prospective surveillance requires extensive resources, we considered a modified approach based on a half-yearly point-prevalence survey of hospital-acquired infections in all wards of our hospital. Such surveillance can be extended with procedure-specific prospective surveillance when indicated.

Surgical site infections in orthopedic surgery: the effect of mupirocin nasal ointment in a double-blind, randomized, placebo-controlled study

The objective of this study was to determine whether use of mupirocin nasal ointment for perioperative eradication of Staphylococcus aureus nasal carriage is effective in preventing the development of surgical site infections (SSIs). A randomized, double-blind, placebo-controlled design was used. Either mupirocin or placebo nasal ointment was applied twice daily to 614 assessable patients from the day of admission to the hospital until the day of surgery. A total of 315 and 299 patients were randomized to receive mupirocin and placebo, respectively. Eradication of nasal carriage was significantly more effective in the mupirocin group (eradication rate, 83.5% versus 27.8%). In the mupirocin group, the rate of endogenous S. aureus infections was 5 times lower than in the placebo group (0.3% and 1.7%, respectively; relative risk, 0.19; 95% confidence interval, 0.02-1.62). Mupirocin nasal ointment did not reduce the SSI rate (by S. aureus) or the duration of hospital stay.

Nasal carriage of Staphylococcus aureus is a major risk factor for surgical-site infections in orthopedic surgery

OBJECTIVE

To determine the relative importance of different risk factors for the development of surgical-site infections (SSIs) in orthopedic surgery with prosthetic implants.

DESIGN

In a cohort of 272 patients, the following possible risk factors were studied: age, gender, method of hair removal, duration of operation, surgeon, underlying illness, and nasal carriage of Staphylococcus aureus. Infections were recorded following the Centers for Disease Control criteria. The relation between risk factors and SSI was tested in univariate and multiple logistic regression analysis.

SETTING

Community hospital in Breda, The Netherlands.

RESULTS

18 (6.6%) of 272 patients experienced SSI: 11 superficial and 7 deep SSI. These infections led in three cases to removal of the prosthesis and caused 286 extra days in hospital. The main causative pathogen was S aureus. In multiple logistic regression analysis, the following factors were independent risk factors for the development of SSI: high-level nasal carriage of S aureus (P=.04), male gender (P=.005), and surgeon 1 (P=.006). The only independent risk factor for SSI with S aureus was high-level nasal carriage of S aureus (P=.002).

CONCLUSION

High-level nasal carriage of S aureus was the most important and only significant independent risk factor for developing SSI with S aureus.

Modifiable risk factors associated with deep sternal site infection after coronary artery bypass grafting

OBJECTIVE

Our objective was to identify risk factors for deep sternal site infection after coronary artery bypass grafting at a community hospital.

METHODS

We compared the prevalence of deep sternal site infection among patients having coronary artery bypass grafting during the study (January 1995-March 1998) and pre-study (January 1992-December 1994) periods. We compared any patient having a deep sternal site infection after coronary artery bypass graft surgery during the study period (case-patients) with randomly selected patients who had coronary artery bypass graft surgery but no deep sternal site infection during the same period (control-patients).

RESULTS

Deep sternal site infections were significantly more common during the study than during the pre-study period (30/1796 [1.7%] vs 9/1232 [0.7%]; P =.04). Among 30 case-patients, 29 (97%) returned to the operating room for sternal debridement or rewiring, and 2 (7%) died. In multivariable analyses, cefuroxime receipt 2 hours or more before incision (odds ratio = 5.0), diabetes mellitus with a preoperative blood glucose level of 200 mg/dL or more (odds ratio = 10.2), and staple use for skin closure (odds ratio = 4.0) were independent risk factors for deep sternal site infection. Staple use was a risk factor only for patients with a normal body mass index.

CONCLUSIONS

Appropriate timing of antimicrobial prophylaxis, control of preoperative blood glucose levels, and avoidance of staple use in patients with a normal body mass index should prevent deep sternal site infection after coronary artery bypass graft operations.

Risk assessment for surgical-site infections in orthopedic patients

OBJECTIVE

To assess the relative importance of risk factors for surgical-site infections (SSIs) in orthopedic patients and thereby determine which risk factors to monitor in the national surveillance of SSI in The Netherlands.

DESIGN

Reanalysis of data on SSI and associated risk factors from two surveillance projects on nosocomial infections, carried out in 1992 and 1993 in The Netherlands: Project Surveillance Nosocomial Infections in the region of Utrecht (PSZU) and the first Project Surveillance Surgical Wound Infections (SWIFT-1). Odds ratios (ORs) were calculated for age, gender, preoperative stay, and the number of operations. In addition, in PSZU, other nosocomial infections, and, in SWIFT-1, prophylactic antibiotics, acute surgery, and wound contamination were studied.

PARTICIPANTS

The study was confined to hospitalized orthopedic patients (PSZU, 4,872; SWIFT-1, 6,437).

RESULTS

In PSZU, the following ORs were significant in a multivariate model: age 0-44 years, 1.0; 45-64 years, 1.6; 65-74 years, 4.7; and 75-99 years, 6.0. For a preoperative stay over 4 days, the OR was 3.3 (95% confidence interval [CI95], 2.5-4.0), and for multiple surgery, 2.5 (CI95, 1.9-3.0). For females, the OR was 0.8 (not significant). The same model applied to SWIFT-1 gave similar ORs. Adjustment for additional nosocomial infections (PSZU) decreased the ORs for ages over 65 years remarkably. The OR for additional nosocomial infections in patients under 65 years of age was 15.6 (CI95, 4.3-57.4). Adjustment for prophylactic antibiotics, acute surgery, and wound-contamination class (SWIFT-1) did not influence the ORs of the original model, but showed that wound-contamination class was an important risk factor.

CONCLUSIONS

Age, additional nosocomial infections, wound-contamination class, preoperative stay, and the number of operations were identified as important risk factors for SSI in Dutch orthopedic patients.

Quality and cost impacts: prevention of post-operative clean wound infections

This paper report the effectiveness of a nursing quality assurance program over three years, which demonstrates improvement in the incidence and severity of post-operative clean wound infections and the associated extended length of hospital stay and cost. General surgery categories included cardiovascular, orthopaedic, neurosurgery, kidney, abdominal, mammary and other. Cardiovascular categories included coronary artery bypass graft (CABG), heart transplant, and atrial valve replacement. Hip replacement and total knee replacement procedures were included in the orthopaedic category. Additional length of stay and concomitant hospital costs were calculated. Results show that early reporting of observations and implementation of appropriate treatment will decrease the incidence, severity and associated costs of post-operative clean wound infections.

Bloodstream, respiratory, and deep surgical wound infections after open heart surgery

Nosocomial infections are one of the most feared complications after open heart surgery. A large retrospective study was conducted to evaluate the nature and scope of the problem. Between 1992 and 1998, 9352 patients who had undergone open heart surgery were evaluated. Bloodstream infections, pneumonia, and deep sternal wound infections were included. Univariate and logistic regression analyses were conducted to identify the high-risk patients that were likely to become infected. Three hundred forty-six infections in 276 patients were diagnosed. Age, preoperative albumin level, banked blood requirement, duration of operation, diabetes mellitus, previous open heart surgery, moderate or severe pericardial adhesions, obesity, postoperative low cardiac output, and postoperative cerebrovascular accident were found to be significant in univariate and logistic regression analyses for infectious outcome. Univariate analysis also revealed additional significant factors: fresh frozen plasma requirement, duration of cardiopulmonary bypass and cross-clamp, preoperative high levels of blood urea and glucose, presence of occlusive peripheral arterial disease, preoperative history of hypertension, and nasal carriage of Staphylococcus aureus. Methicillin resistant S. aureus was involved in 58.4% of the infections. Risk factors should be individualized for patients and every effort should be carried out to minimize infectious outcome.

Sternal wound infection after heart operations in pediatric patients associated with nasal carriage of Staphylococcus aureus

A cluster of six pediatric cases of deep-seated Staphylococcus aureus infection after heart operations prompted us to perform molecular typing of the S. aureus isolates by pulsed-field gel electrophoresis. This revealed the presence of genotypically distinct isolates in four of the six patients. Isolates of two patients were genotypically identical. All patients carried S. aureus in the anterior nares. In each patient, the banding pattern of deoxyribonucleic acid in these isolates was indistinguishable from that in strains isolated from blood or wound cultures. Molecular typing with pulsed-field gel electrophoresis ruled out nosocomial transmission of S. aureus between four patients; at the same time, it provided evidence for an association between nasal colonization and postoperative wound infection. Epidemiologic investigation of potential links between two patients with identical isolates did not provide any evidence for nosocomial transmission of S. aureus between these patients. Because nasal colonization with S. aureus may be a risk factor for surgical wound infection in pediatric patients undergoing heart operations, preoperative decolonization appears to be warranted.

Epidemiological methods in the study of surgical wound infection

Epidemiology can provide the knowledge necessary to allocate resources appropriately, but awareness of the advantages and disadvantages of different study methods is essential

Potential for reduction in morbidity and cost with total leucocyte control for cardiac surgery

The economics of health care in the USA and abroad has caused a shift in the focus on therapeutic interventions that transcend issues of safety and clinical efficacy. Now, cost justification is emerging as a major consideration to influence clinical practice. This brief review of the medical literature attempts to identify leucocyte-mediated adverse reactions that develop in open-hear surgery, quantify the costs incurred to manage such reactions and infer the savings that may accrue by controlling the burden of leucocytes presented to the open-heart surgical patient using commercially available leucocyte reducing filtration technology.