Influence of nosocomial infection on mortality rate in an intensive care unit

Epidemiology of intensive care unit (ICU)-acquired infections in a 14-month prospective cohort study in a single mixed Scandinavian university hospital ICU

BACKGROUND

Our aim was to evaluate the epidemiology of intensive care unit (ICU)-acquired infections in a prospective cohort study.

METHODS

Patients with longer than a 48-h stay in an adult mixed medical-surgical ICU in a tertiary level teaching hospital were included. The incidence (per cent) and incidence density (per 1000 patient days) of ICU-acquired infections and the device-associated infection rates per 1000 device days were analysed prospectively in a 14-month study.

RESULTS

Eighty (23.9%) of 335 patients, whose ICU stay was longer than 48 h, acquired a total of 107 infections (1.3 per patient) during their ICU stay, with an infection rate of 48 per 1000 patient days. The most common infections were ventilator-associated pneumonia (VAP) [33.8% (18.8 per 1000 respiratory days)], other lower respiratory tract infections (LRTIs) (20%) and sinusitis (13.8%). The rate of central catheter-related (CRI) or primary bloodstream infections was 6.3% (2.2 per 1000 central venous catheter days), and the rate of urinary tract infections was 1.3% (0.5 per 1000 urinary catheter days). The first ICU infection was observed in 58.8% (47/80) of cases within 6 days after admission. The median time from admission to the diagnosis of an ICU-acquired infection was 4 days (25th-75th percentiles, 4.0-6.0) for VAP, 6.0 days (4.5-7.0) for LRTIs and 9.5 days (6.5-13.0) for CRIs.

CONCLUSIONS

The rates of urinary tract infections and bloodstream infections were lower than reported previously, differentiating our results from the classic pattern of ICU-acquired infections, with the exception of the predominance of VAP.

[Management of ventilator acquired pneumonia]

Ventilator-associated pneumonia occurs in the evolution of 8 to 70% of patients in the Intensive Care Unit. It is the main site of nosocomial infection for mechanically ventilated patients. Nosocomial pneumonia represents an important cause of morbidity and mortality, despite progresses in antibiotic prescription, use of intensive care and prevention. This review is based on the ATS guidelines, and reviews epidemiology, diagnosis and treatment of ventilator-acquired pneumonia, in non-immunocompromised adults.

The Burden of Nosocomial Infection in the Intensive Care Unit: Effects on Organ Failure, Mortality and Costs. A Nested Case-Control Study

BACKGROUND

Nosocomial infections increase mortality and costs in the intensive care units; however, few studies have addressed organ failure that developed in infected patients and their overall costs. The goal of this study was to measure the frequency of organ failure in nosocomial infection and the mortality and costs of these in critical care areas.

METHODS

This was a nested 1:2 case-control study in a cohort of all consecutively hospitalized patients comparing those with and without nosocomial infections over a year in an institutional intensive care unit (ICU). Those patients who acquired an infection during hospitalization were considered cases. Controls were matched by hospital stay at least as long as the cases' time acquisition of nosocomial infection, age +/-5 years and APACHE II +/-5 points.

RESULTS

Forty-three patients developed at least one nosocomial infection event (cases). The matching success was about 94%. Higher frequency and duration of organ failures was observed in the cases, as well as the number of devices and procedures (p < 0.05). Attributable mortality was 16.3% (p < 0.001). Attributable total cost of a nosocomial infection acquired in the ICU was 12,155 dollars.

CONCLUSIONS

Nosocomial infection acquired in the ICU increases length of stay, frequency and duration of organ failures, mortality, and costs.

Epidemiologische Grundlagen

Eine Vielzahl an Faktoren tragen zu erhöhten nosokomialen Infektionsraten bei. Die Lebenserwartung und damit der Anteil alter Patienten mit z. T. chronischen Krankheiten steigen stetig an. Medizinische Fortschritte in Diagnostik und Therapie führen zu einer höheren Anzahl der dafür erforderlichen Eingriffe. Es werden immer häufiger immunsupprimierte Patienten (Infektiologie, Rheumatologie, Hämatologie/Onkologie, Transplantation von Organen usw.) behandelt. Das zunehmende Problem der Antibiotikaresistenz von Erregern und die Konsequenzen nosokomialer Infektionen erfordern eine verlässliche Epidemiologie auf diesem Gebiet. Konsequenzen betreffen einerseits Patienten, bei denen es zu einer erhöhten Morbidität und Letalität durch nosokomiale Infektionen kommt, aber andererseits auch das Gesundheitswesen, dem zusätzliche — vermeidbare? — finanzielle Belastungen entstehen.

Evidenzbasierte Empfehlungen, bei denen der jeweilige Einzelfall und die örtlichen Besonderheiten ebenfalls Berücksichtigung finden, sind Voraussetzung für eine sinnvolle und kosteneffektive Vorgehensweise zur Senkung der nosokomialen Infektionsrate. In vielen Studien sind Häufigkeiten und Folgen verschiedener nosokomialer Infektionsarten sowie Maßnahmen zu ihrer Prävention untersucht worden. Um die Qualität solcher Studien und die darauf basierenden Empfehlungen von Experten, die ja oftmals ebenfalls mit Kosten verbunden sind, kritisch beurteilen zu können, ist epidemiologisches Wissen unverzichtbar. Dies beinhaltet selbstverständlich auch die Kenntnis der jeweiligen Erreger solcher Infektionen sowie das Wissen um erregerspezifische Übertragungswege. Die Epidemiologie nosokomialer Infektionen ist daher die Grundlage ihrer eigenen Verbesserung.

»Es gibt nicht Kranke und Gesunde, sondern es gibt nur Untersuchte und nicht Untersuchte« (Johannes Rau, ehemaliger Bundespräsident).

Neumonía por Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the leading causes of Gram-negative nosocomial pneumonia. It is the most common cause of ventilator-associated pneumonia and carries the highest mortality among hospital-acquired infections. P. aeruginosa produces a large number of toxins and surface components that make it especially virulent compared with other microorganisms. These include pili, flagella, membrane bound lipopolysaccharide, and secreted products such as exotoxins A, S and U, elastase, alkaline protease, cytotoxins and phospholipases. The most common mechanism of infection in mechanically ventilated patients is through aspiration of upper respiratory tract secretions previously colonized in the process of routine nursing care or via contaminated hands of hospital personnel. Intravenous therapy with an antipseudomonal regimen should be started immediately when P. aeruginosa pneumonia is suspected or confirmed. Empiric therapy with drugs active against P. aeruginosa should be started, especially in patients who have received previous antibiotics or present late-onset pneumonia.

Increased risk of bloodstream and urinary infections in intensive care unit (ICU) patients compared with patients fitting ICU admission criteria treated in regular wards

Critically ill patients, eligible for admission into intensive care units (ICUs), are often hospitalized in other wards due to a lack of ICU beds. Differences in morbidity between patients managed in ICUs and elsewhere are unknown, specifically the morbidity related to hospital-acquired infection. Patients fitting ICU admission criteria were identified by screening five entire hospitals on four separate days. Hospital infections within a 30-day follow-up period were compared in ICU patients and in patients on other wards using Kaplan-Meier curves. Residual differences in the patients' case mix between ICUs and other wards were adjusted for utilizing multivariate Cox models. Of 13415 patients screened, 668 were critically ill. The overall infection rates (per 100 patient-days) were 1.2 for bloodstream infection (BSI) and 1.9 for urinary tract infection (UTI). The adjusted hazard ratios in ICU patients compared with patients on regular wards were 3.1 (P<0.001) for BSI and 2.5 (P<0.001) for UTI. This increased risk persisted even after adjusting for the disparity in the number of cultures sent from ICUs compared with ordinary wards. No interdepartmental differences were found in the rates of pneumonia, surgical wound infections and other infections. Minimizing the differences between characteristics of patients hospitalized in ICUs and in other wards, and controlling for the higher frequency of cultures sent from ICUs did not eliminate the increased risk of BSI and UTI associated with admission into ICUs.

Does enteral nutrition compared to parenteral nutrition result in better outcomes in critically ill adult patients? A systematic review of the literature

OBJECTIVE

Nutritional support is part of the standard of care for the critically ill adult patient. In the average patient in the intensive care unit who has no contraindications to enteral nutrition (EN) or parenteral nutrition (PN), the choice of route for nutritional support may be influenced by several factors. Because EN and PN are associated with risks and benefits, we systematically reviewed and critically appraised the literature to compare EN with PN the critically ill patient.

METHODS

We searched computerized bibliographic databases, personal files, and relevant reference lists to identify potentially eligible studies. Only randomized clinical trials that compared EN with PN in critically ill patients with respect to clinically important outcomes were included in this review. In an independent fashion, relevant data on the methodology and outcomes of primary studies were abstracted in duplicate. The studies were subsequently aggregated statistically.

RESULTS

There were 13 studies that met the inclusion criteria and, hence, were included in our meta-analysis. The use of EN as opposed to PN was associated with a significant decrease in infectious complications (relative risk = 0.64, 95% confidence interval = 0.47 to 0.87, P = 0.004) but not with any difference in mortality rate (relative risk = 1.08, 95% confidence interval = 0.70 to 1.65, P = 0.7). There was no difference in the number of days on a ventilator or length of stay in the hospital between groups receiving EN or PN (Standardized Mean Difference [SMD] = 0.07, 95% confidence interval = -0.2 to 0.33, P = 0.6). PN was associated with a higher incidence of hyperglycemia. Data that compared days on a ventilator and the development of diarrhea in patients who received EN versus PN were inconclusive. In the EN and PN groups, complications with enteral and parenteral access were seen. Four studies documented cost savings with EN as opposed to PN.

CONCLUSION

The use of EN as opposed to PN results in an important decrease in the incidence of infectious complications in the critically ill and may be less costly. EN should be the first choice for nutritional support in the critically ill.

Relationship between nosocomial infection and mortality in a neurology intensive care unit in Turkey

Few previous studies have evaluated the relationship between nosocomial infection and mortality in a neurology intensive care unit (ICU). In this study, patients treated for more than 24h in the neurology ICU of the Ankara Training and Research Hospital, Turkey were followed until death or two days after discharge by prospective daily surveillance. The study period was 14 months. One hundred and sixty-nine ICU-acquired infections occurred in 74 (38.9%) of 190 patients during 2006 patient-days. The overall rate of ICU-acquired nosocomial infection was 88.9/100 patients and 84.2/1000 patient-days. While the overall mortality rate was 60%, mortality in patients with nosocomial infections was 69%. In univariate analysis, infection (nosocomial and community-acquired) (P=0.002), nosocomial infection (P<0.05), mechanical ventilation (P<0.0001), presence of two or more underlying diseases (P=0.01), parenteral nutrition (P<0.0001), steroid treatment (P=0.003) and a low Glasgow Coma Scale (GCS) score (P=0.0001) were identified as risk factors for mortality. Stepwise logistic regression analysis showed nosocomial infection (P<0.05), mechanical ventilation (P=0.009), the presence of two or more underlying diseases (P<0.05) and a low GCS score (P=0.0001) to be risk factors for ICU mortality. It was concluded that nosocomial infection increases the risk of mortality by a factor of 1.69. The impact of nosocomial infection on mortality in our ICU was higher in patients with high GCS scores and patients aged between 66 and 75 years. In particular, nosocomial infection increased mortality among patients with less severe illnesses.

Is ventilator-associated pneumonia in trauma patients an epiphenomenon or a cause of death?

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common infection among patients in trauma intensive care units (ICUs). It has been suggested by different investigators that VAP is an indicator of injury severity and not necessarily associated with mortality. Crude mortality rates approximating 20% have been reported for trauma patients with VAP. Most studies have involved the most severely injured patients, making it difficult to determine the relative contribution of either VAP or injury severity to death. If VAP is independently associated with mortality, this relationship should be most evident in less severely injured patients. We studied patients with less severe injuries (Injury Severity Score, ISS < 25) to determine the impact of VAP on outcomes.

METHODS

Patients admitted to the trauma ICU with ISS < 25 were identified from the trauma registry of a level I trauma center. Patients with penetrating injuries and those who died within 48 h of injury were excluded. Pneumonia was diagnosed using quantitative cultures of bronchoalveolar lavage effluent (>/= 10(5) colony forming units/mL). Risk factors for VAP, including age, transfusions with 24 h of admission, brain injury, and chest injury severity were analyzed. Logistic regression analysis was then performed to determine independent factors for death.Results: There were 15,492 blunt admissions over a 5.5 year study period who survived >48 h. Of these, 5,860 (38%) were admitted to the ICU, and 4,111 (70% of ICU admissions) had ISS < 25. The incidence of VAP in this group was 8%. Patients with VAP were older (47 vs 39 years), had more transfusions within 24 h (2.5 vs 0.9 units of red blood cell concentrates) and had greater injury severity by ISS (16.7 vs 12.6 points), GCS (Glasgow Coma Scale) score (11.8 vs. 13.7 points) and chest AIS (Abbreviated Injury Scale) (1.7 vs 0.9 points; all p < 0.001). Overall mortality was 4%. Mortality was 16% in patients with VAP compared to 3% in those without VAP (p < 0.0001). Logistic regression analysis identified transfusions, age, and VAP as independent predictors of mortality. Other descriptors of injury severity (ISS, GCS, or chest AIS) were not associated with death.

RESULTS

There were 15,492 blunt admissions over a 5.5 year study period who survived . 48 h. Of these, 5,860 (38%) were admitted to the ICU, and 4,111 (70% of ICU admissions) had ISS , 25. The incidence of VAP in this group was 8%. Patients with VAP were older (47 vs 39 years), had more transfusions within 24 h (2.5 vs 0.9 units of red blood cell concentrates) and had greater injury severity by ISS (16.7 vs 12.6 points), GCS (Glasgow Coma Scale) score (11.8 vs. 13.7 points) and chest AIS (Abbreviated Injury Scale) (1.7 vs 0.9 points; all p , 0.001). Overall mortality was 4%. Mortality was 16% in patients with VAP compared to 3% in those without VAP (p , 0.0001). Logistic regression analysis identified transfusions, age, and VAP as independent predictors of mortality. Other descriptors of injury severity (ISS, GCS, or chest AIS) were not associated with death.

CONCLUSIONS

Ventilator-associated pneumonia is independently associated with death in less severely injured trauma patients. This demonstrates the need for effective diagnostic techniques so that adequate therapy may be initiated. Prevention of VAP in less severely injured trauma patients should increase survival.

Cost of a Ventilator-Associated Pneumonia in a Shock Trauma Intensive Care Unit

BACKGROUND

Nosocomial pneumonia and especially ventilator-associated pneumonia (VAP) are costly complications for the hospitalized patient. Nosocomial pneumonia has been estimated to cost $5,000 per episode, but the specific cost for a VAP has not been well estimated. As part of a successful performance improvement program in decreasing VAP from 10 VAPs/100 ICU admissions to 2.5 VAPs/100 ICU admissions, we examined the costs associated with VAP.

METHODS

From January 1, 2002, through September 30, 2003, Shock Trauma Intensive Care Unit patients and charts were reviewed concurrently by an infection control practitioner for development of VAP as defined by National Nosocomial Infection Surveillance (NNIS) guidelines. Costs were obtained from the hospital's cost accounting software Transition Systems version 3.1.01 (TSI). All patients requiring greater than one day of mechanical ventilation were evaluated. Seventy patients with VAP and 70 patients without VAP were matched according to age and Injury Severity Score. Differences were compared using Kruskal-Wallis and two sample T-tests. Significance was considered for p < 0.05.

RESULTS

The ICU cost difference was significant (p < 0.05) between the case-controlled patients with VAP ($82,195) and those without VAP ($25,037). There was also a significant increase in ICU length of stay (21.6 versus 6.4 days) and the number of ventilator days (17.7 versus 5.8; both, p < 0.05). Mortality was not different in the case-controlled population. A substantial portion of the increased cost of a VAP was from the increase in ICU length of stay ($1,861/day). Pharmacy, respiratory and "other" also accounted for the increases when cost distribution was analyzed. This translates into a cost avoidance of approximately $428,685 per 100 admissions to the ICU.

CONCLUSIONS

Ventilator-associated pneumonia not only leads to a significant increase in ventilator days and ICU length of stay, but adds substantially to hospital costs. In our ICU, an episode of VAP costs $57,000 per occurrence.

Evaluation of risk factors for mortality in intensive care units: a prospective study from a referral hospital in Turkey

BACKGROUND

The aim of the clinical practice is to decrease the mortality rate in intensive care units. Determination of the risk factors for mortality may provide useful guidance for intensive care patients. This study sought to find mortality-related risk factors in intensive care units.

OBJECTIVE

To investigate risk factors for mortality in intensive care units (ICUs).

METHODS

The prospective study was performed from May 2002 to November 2002 in the surgical and medical ICUs of the Ankara Numune Education and Research Hospital. Three hundred thirty-four patients who were followed in the ICUs for at least 48 hours were enrolled in this study. Those patients who died within 48 hours of ICU discharge were included in the mortality analysis.

RESULTS

The overall mortality rate in the ICUs was 46.7%. Among the 334 patients, 104 (31.1%) had ICU-acquired infections. The mortality rate was significantly higher in the patients with nosocomial infections (66.3%) than in the patients without nosocomial infections (37.8%) ( P < .001). The mean age, sex, acute physiology and chronic health evaluation (APACHE) II score, trauma and intraabdominal pathology, nosocomial infection, stay in the medical/surgical ICU, coma, TISS score, use of steroid or chemotherapy, use of antibiotic, and serum urea >50 mg/dL and creatinine >1.2 mg/dL levels were associated with mortality in the univariate analysis. Eight variables were determined as independent risk factors: presence of nosocomial infection (hazard ratio (HR) 0.40; 95% confidence interval (CI), 0.27-0.61), mean age (HR, 1.01; 95% CI, 1.00-1.02), mean APACHE II score (HR, 1.99; 95% CI, 1.50-2.64), mechanical ventilation (HR, 1.98; 95% CI, 1.33-2.95), stay in the medical/surgical ICU (HR, 0.41; 95% CI, 0.27-0.61), enteral nutrition (HR, 0.43; 95% CI, 0.29-0.65), tracheostomy (HR, 0.26; 95% CI, 0.094-0.75), and use of steroid or chemotherapy (HR, 1.61; 95% CI, 1.13-2.29). Nosocomial pneumonia (HR, 0.59; 95% CI, 0.38-0.92) and sepsis (HR, 0.29; 95% CI, 0.16-0.51) were related with mortality.

CONCLUSION

The most important risk factors of mortality were observed as nosocomial infection, older age, high APACHE II score, mechanical ventilation, enteral nutrition, tracheostomy, and use of steroids or chemotherapy.

Nosocomial infections and hospital mortality: a multicentre epidemiology study

The aim of this study was to evaluate the number of deaths associated with nosocomial infections (NI) and the contribution of these NI to death. A multicentre descriptive study was conducted in 16 tertiary-care hospitals (14 222 beds) in Northern France. Medical records of consecutive patients who died at least 48 h after admission were reviewed for cause of death, NI and disease severity, before admission and before NI onset. The contribution of NI to death was assessed by agreement between two physicians according to a three-category scale of probability. Among the 1945 patients who died during the study, 26.6% had an NI. According to the agreed diagnosis, NI contributed to the deaths of 284 (14.6%) patients(certainly for 6.6% and possibly for 8%), thereby ranking NI as the fourth most frequent cause of death. Considering the deaths that had not been anticipated independently of NI two weeks before they occurred, NI definitely contributed to 2.8% of them. Lower respiratory tract, bloodstream and surgical wound infections were responsible for 39, 20 and 14%, respectively,of all NI in these patients. The impact of NI on in-hospital mortality seems to be lower than had previously been estimated in France based on US data from the 1970s and 1980s. To improve healthcare quality, further studies are needed to elucidate the processes that may contribute to fatal severe NI.

Validation of the Canadian clinical practice guidelines for nutrition support in mechanically ventilated, critically ill adult patients: Results of a prospective observational study*

OBJECTIVE

Recently, evidence-based clinical practice guidelines for the provision of nutrition support in the critical care setting have been developed. To validate these guidelines, we hypothesized that intensive care units whose practice, on average, was more consistent with the guidelines would have greater success in providing enteral nutrition.

DESIGN

Prospective observational study.

SETTING

Fifty-nine intensive care units across Canada.

PATIENTS

Consecutive cohort of mechanically ventilated patients.

INTERVENTIONS

In May 2003, participating intensive care units recorded nutrition support practices on a consecutive cohort of mechanically ventilated patients who stayed for a minimum of 72 hrs. Sites enrolled an average of 10.8 (range, 4-18) patients for a total of 638. Patients were observed for an average of 10.7 days.

MEASUREMENTS AND MAIN RESULTS

We examined the association between five recommendations from the clinical practice guidelines most directly related to the provision of nutrition support (use of parenteral nutrition, feeding protocol, early enteral nutrition, small bowel feedings, and motility agents) and adequacy of enteral nutrition. We defined adequacy of enteral nutrition as the percent of prescribed calories that patients actually received. Across sites, the average adequacy of enteral nutrition over the observed stay in intensive care unit ranged from 1.8% to 76.6% (average 43.0%). Intensive care units with a greater than median utilization of parenteral nutrition (>17.5% patient days) had a much lower adequacy of enteral nutrition (32.9 vs. 52.7%, p < .0001). Intensive care units that used a feeding protocol tended to have a higher adequacy of enteral nutrition than those that did not (44.9 vs. 38.5%, p = .03). Intensive care units that initiated enteral nutrition on >50% of their patients within the first 48 hrs had a higher adequacy of enteral nutrition than those that did not (48.1 vs. 34.4%, p < .0001). Intensive care units that had a >50% utilization of motility agents and/or any small bowel feedings in patients with high gastric residuals tended to have a higher adequacy of enteral nutrition than those intensive care units that did not (45.6 vs. 39.2%, p = .04, and 48.4 vs. 41.8%, p = .16, respectively).

CONCLUSIONS

Intensive care units that were more consistent with the Canadian clinical practice guidelines were more likely to successfully feed patients via enteral nutrition. Adoption of the Canadian clinical practice guidelines should lead to improved nutrition support practice in intensive care units. This may translate into better outcomes for critically ill patients receiving nutrition support.

Efficacy of adequate early antibiotic therapy in ventilator-associated pneumonia: influence of disease severity

OBJECTIVE

To test the hypothesis that the outcome of patients with ventilator-associated pneumonia (VAP) depends on both their baseline severity at VAP onset and the adequacy of empirical antibiotic therapy.

DESIGN AND SETTING

Prospective clinical study in six intensive care units in Paris, France.

PATIENTS

One hundred and forty-two patients with VAP after >/= 48 h of mechanical ventilation.

MEASUREMENTS AND RESULTS

Patients were compared according to whether adequate antibiotics were started when VAP was first suspected (D0). At day 0, the rate of adequate antibiotic therapy was 44.4% and rose to 92% at day 2. Outcomes were recorded at the ICU and hospital discharge. Overall, no significant mortality difference was found with and without adequate early antibiotics. When patients were also classified based on the initial Logistic Organ Dysfunction score (LOD), mortality was significantly higher with inadequate early antibiotic therapy in the groups with LOD </= 4 (ICU mortality: 37% vs 7%, P=0.006; hospital mortality: 44% vs 15%, P=0.01). A multivariate logistic regression confirmed that inadequate antibiotic therapy increased mortality in patients with LOD </= 4 after adjustment on other prognostic factors.

CONCLUSIONS

Inadequate empirical treatment seemed to be associated with a poor prognosis only in patients with LOD </= 4. These results need to be confirmed by further studies before any reappraisal of current guidelines for empirical antibiotic therapy of VAP can be envisaged.

Device-associated nosocomial infection rates in intensive care units of Argentina

BACKGROUND

Nosocomial infections are an important public health problem in many developing countries, particularly in the intensive care unit (ICU) setting. No previous data are available on the incidence of device-associated nosocomial infections in different types of ICUs in Argentina.

METHODS

We performed a prospective nosocomial infection surveillance study during the first year of an infection control program in six Argentinean ICUs. Nosocomial infections were identified using the Centers for Disease Control and Prevention National Nosocomial Infections Surveillance System definitions, and site-specific nosocomial infection rates were calculated.

RESULTS

The rate of catheter-associated bloodstream infections in medical-surgical ICUs was 30.3 per 1,000 device-days; it was 14.2 per 1,000 device-days in coronary care units (CCUs). The rate of ventilator-associated pneumonia in medical-surgical ICUs was 46.3 per 1,000 device-days; it was 45.5 per 1,000 device-days in CCUs. The rate of symptomatic catheter-associated urinary tract infections in medical-surgical ICUs was 18.5 per 1,000 device-days; it was 12.1 per 1,000 device-days in CCUs.

CONCLUSION

The high rate of nosocomial infections in Argentinean ICUs found during our surveillance suggests that ongoing targeted surveillance and implementation of proven infection control strategies is needed in developing countries such as Argentina.

Nosocomial Infections Adversely Affect the Outcomes of Patients with Serious Intraabdominal Infections

BACKGROUND

Patients with serious intraabdominal infections (IAI) who subsequently acquire nosocomial infections (NI) have been shown to have adverse outcomes. We evaluated factors that put patients at risk for developing NI and examined the effect of the NI on outcomes.

METHODS

This study was a retrospective review of NI among 168 patients diagnosed with IAI over a seven-year period.

RESULTS

Sixty-six patients (39.3%) developed 98 NI (23 urinary tract, 20 surgical site, 19 pneumonia, 14 bloodstream, 12 recurrent peritonitis, seven intravascular catheter-related, and three enteric). There were 35 males and 31 females. Patients with NI were older (56.0 +/- 18.3 vs. 47.0 +/- 15.6 years, p = 0.001), had a higher admission APACHE II score (10.7 +/- 6.1 vs. 7.5 +/- 5.1 points, p = 0.001), and more often had concomitant medical diagnoses (27.3% vs. 12.7%, OR = 2.57, 95% CI: 1.159-5.69, p = 0.018) than those who did not develop infection. Antimicrobial resistance among the IAI was higher in the NI group (19.7 vs. 5.9%, OR = 3.93, 95% CI: 1.41-10.93, p = 0.006). Patients who developed NI had an increased mortality rate (27.0% vs. 4.0%, OR = 8.87, 95% CI: 2.82-27.86, p < or = 0.0001), longer hospital stay (24.7 +/- 19.5 vs. 11.7 +/- 8.1 days, p < or = 0.0001), required more days of intravenous antibiotics (11.5 +/- 8.0 vs. 7.6 +/- 4.4 days, p < or = 0.0001), and were more likely to be admitted to an intensive care unit (54.5% vs. 25.5%, OR = 3.51, 95% CI: 1.82-6.77, p < or = 0.0001). Multivariate analysis demonstrated that antimicrobial resistance and an APACHE II score of > or = 10 independently predicted the development of a nosocomial infection. Age >/= 50 years, APACHE II score > or = 10, or the presence of a NI independently predicted death.

CONCLUSIONS

The development of NI following treatment of an IAI significantly affects mortality, hospital length of stay, and treatment. Early recognition and treatment of these infections, combined with strategies to prevent NI, may be important to improve outcomes in this patient population.

Mortalité hospitalière imputable aux infections nosocomiales : mise en place d’un observatoire dans un centre hospitalier universitaire

OBJECTIVE

A system for monitoring deaths was set up at the Besançon University Hospital, in the Franche-Comté region of France, in January 2002. This article describes the principal results after 1 year of activity.

MATERIALS AND METHODS

The main outcome was the descriptive surveillance of deaths due to nosocomial infections (NI), by means of a two-step process, in the identification of cases. The first step was the declaration of information concerning the possible existence of an NI at the time of death and the assignment of a prognostic score to each patient upon admission. The second step involved comparison of opinions concerning cases "selected" on the basis of clinical records. This system was completed by a methodological analysis of deaths considered to be partially or totally due to NIs, with the aim to suggest preventive actions.

RESULTS

The overall rate of mortality in our hospital was 2.44 per 100 patients admitted. The overall proportion of deaths linked to hospital-acquired infections was 15.3%. We analysed eight of the 20 deaths possibly due to NI (MacCabe score of 1 or 0) in detail. In three of these eight cases, we showed that the cause of death was not NI. Methodical analysis of patient records showed that corrective actions could have been taken in three of these five cases.

CONCLUSION

Our study suggests that it is possible to monitor deaths due to nosocomial infections continuously in a university hospital and favours re-implementing death analysis committees acknowledging the "useful error" concept which is culturally difficult to accept.

Intensive care unit acquired infection: a prevalence and impact on morbidity and mortality

BACKGROUND

Severe infection is a common reason for intensive care and contributes to increased morbidity and mortality. The aim of the study was to determine the prevalence of infection among intensive care unit (ICU) patients and to evaluate the consequences of ICU-acquired infection on morbidity and mortality.

METHODS

A total of 812 patients consecutively admitted for more than 48 h to the ICU at Vilnius University Emergency Hospital, Lithuania, were included in the prospective observational study. Organ dysfunction was assessed using the Sequential Organ Failure Assessment (SOFA) system.

RESULTS

Thirty-seven per cent of patients were identified who developed at least one ICU-acquired infection. Respiratory, bloodstream and urinary tract infections were the most common. The main isolates were coagulase-negative Staphylococcus, S. aureus, Acinetobacter and Pseudomonas species. More severe degree of organ dysfunction, prolonged stay in the ICU and higher hospital mortality rate were more common among patients who acquired infection in the ICU than that of non-infected patients.

CONCLUSION

The prevalence of infection in the ICU was similar to other studies in European countries. The occurrence of ICU-acquired infection was significantly related to the increase in morbidity and mortality. The findings are useful for the comparison of the prevalence rate of infection and implementation of strict infection control policy.

Ventilator-associated pneumonia and atelectasis: evaluation through bronchoalveolar lavage fluid analysis

OBJECTIVE

Surfactant offers protection against alveolar collapse and contributes to the local defense mechanism, but it is unclear if surfactant alterations have a role in the development of atelectasis or ventilator-associated pneumonia (VAP). The present study was undertaken to monitor surfactant, as well as biochemical BAL fluid alterations, during the course of VAP and atelectasis in mechanically ventilated patients without primary cardiopulmonary disease, to elucidate the pathogenesis and to differentiate these two entities. DESIGN. Prospective controlled study.

SETTING

14-bed general ICU of a 750-bed University Hospital.

PATIENTS

Sixty-one ventilated patients, without primary cardiopulmonary disease-normal initial chest X-ray, satisfactory oxygenation (PaO(2)/FiO(2)>300 mmHg), and expected time of ventilation exceeding 2 weeks-were initially enrolled. Twelve of them developed VAP and eight lobar or segmental atelectasis during the 2-week study period.

INTERVENTIONS

An initial BAL was performed in all patients within 48 h from admission. Patients who developed VAP or atelectasis were subjected to a second and third BAL during and after the resolution of VAP or atelectasis, respectively.

MEASUREMENTS AND RESULTS

VAP and atelectasis resulted in a significant increase of total protein and markers of inflammation, such as PAF and neutrophils, which partially remitted after their resolution. Large surfactant aggregates, which contribute to surface tension decrease, were significantly reduced during both entities and remained low even after their resolution.

CONCLUSIONS

BAL alterations during VAP and atelectasis suggest increased alveolar-capillary permeability, severe surfactant abnormalities, and signs of local inflammatory reaction. These alterations are associated with the observed deteriorated gas exchange and lung mechanics and could predispose to further lung injury in ventilated patients.

Factors related to hospital stay among patients with nosocomial infection acquired in the intensive care unit

OBJECTIVES

To assess the influence of nosocomial infection on length of stay in the intensive care unit (ICU) and to determine the relative effect of other factors on extra length of hospitalization associated with nosocomial infection.

DESIGN

Prospective cohort multicenter study in the context of the ENVIN-UCI project.

SETTING

Medical or surgical ICUs of 49 different hospitals in Spain.

METHODS

All consecutive patients (N = 6,593) admitted to ICUs of the participating hospitals who stayed for more than 24 hours during a 3-month period (from January 15 to April 15, 1996) were included. Length of ICU stay was compared between patients with and without nosocomial infections. RESULTS Uninfected patients (N = 5,868) had a median stay in the ICU of 3 days, whereas the median for infected patients (N = 725) was 17 days (P < .001). The median for infected patients with one episode of nosocomial infection was 13 days. The greatest length of stay (40 days) was among patients admitted to the ICU because of medical diseases, with an infection acquired before admission to the ICU, and with the largest number of nosocomial infection episodes. In extended stays, nosocomial infection was significantly associated with length of hospitalization (day 21; odds ratio, 22.38; 95% confidence interval 16.6 to 30.4), whereas an effect of variables related to severity of illness on admission (Acute Physiology and Chronic Health Evaluation II score, urgent surgery, and infection prior to ICU admission) was not found.

CONCLUSIONS

The presence of nosocomial infection and the number of infection episodes were the variables with the strongest association with prolonged hospital stay among ICU patients.

Nosocomial pneumonia: the importance of a de-escalating strategy for antibiotic treatment of pneumonia in the ICU

Nosocomial pneumonia is the second most frequent nosocomial infection and represents the leading cause of death from infections that are acquired in the hospital. In the last decade, a large body of data has accumulated that points to the substantial impact of inadequate antibiotic treatment as a major risk factor for infection-attributed mortality in ventilator-associated pneumonia (VAP) patients. In most instances, high-risk pathogens (eg, highly resistant Gram-negative bacilli, such as Pseudomonas aeruginosa and Acinetobacter spp, as well as methicillin-resistant staphylococci) are the predominant microorganisms causing excess mortality. Among various risk factors for mortality from VAP, which include the severity of the underlying disease and the degree of functional physiologic impairment caused by the pulmonary infectious process, only inappropriate antibiotic therapy is directly amenable to modification by clinicians. Secondary modifications of an initially failing antibiotic regimen do not substantially improve the outcome for these critically ill patients. Therefore, the best approach for reducing infection-related mortality seems to be the initial institution of an adequate and broad-spectrum antibiotic regimen in severely ill patients, which should be modified in a de-escalating strategy when the results from microbiologic testing become available. To circumvent the inherent danger of the emergence of resistance in ICU patients, additional measures have to be implemented and tested in clinical trials to reduce antibiotic consumption, shorten the duration of antibiotic treatment, and reduce the selection pressure on the ICU flora. This latter goal could be met by new antibiotic strategies including scheduled changes of recommended empiric antibiotic regimens at fixed intervals on a rotating basis.

Do isolation rooms reduce the rate of nosocomial infections in the pediatric intensive care unit?

PURPOSE

To determine the effect of isolation rooms on the direct spread of nosocomial infections (NIs) owing to cross-colonization in a pediatric intensive care unit (PICU).

MATERIALS AND METHODS

This 6-month comparative clinical study used retrospective data from 1992 (an open single-space unit) and prospective surveillance from 1995 (individual rooms) to assess the effectiveness of the latter design on the control of NIs in critically ill pediatric patients. Patients admitted to the PICU for at least 48 hours underwent a microbiologic survey.

RESULTS

The average number of NIs per patient was higher in 1992 (3.62 +/- 0.7, 78 patients) compared with 1995 (1.87 +/- 0.2, 115 patients). Bacterial NIs were caused by gram-positive cocci (33.3%) and aerobic gram-negative bacilli (66.6%). Fungemia in all cases was caused by Candida albicans. Similarly, length of stay was significantly higher in 1992 compared with 1995 (25 +/- 6 and 11 +/- 6 days, respectively; P <.05). There was a significant reduction of respiratory and urinary tract episodes of NI as well as catheter-related infections in the separate room arrangement.

CONCLUSIONS

Our preliminary analysis suggests a possible beneficial effect of single isolation rooms in reducing NI rate in the PICU. Hence, the influence of room isolation on NIs in pediatric intensive care warrants further investigation.

Optimizing the benefits and minimizing the risks of enteral nutrition in the critically ill: role of small bowel feeding

BACKGROUND

Strategies that maximize the delivery of enteral nutrition while minimizing the associated risks have the potential to improve the outcomes of critically ill patients. By delivering enteral feeds in the small bowel, beyond the pylorus, the frequency of regurgitation and the risk of aspiration is thought to be decreased while at the same time, nutrient delivery is maximized. The purpose of this paper is to systematically review those studies that compare gastric with small bowel feeding.

METHODS

We searched computerized bibliographic databases, personal files, and relevant reference lists to identify eligible studies. Only randomized, clinical trials of critically ill patients that compared small bowel and gastric feedings were included in this review. In an independent fashion, relevant data on the methodology and outcomes of primary studies were abstracted in duplicate.

RESULTS

There were 10 studies that met the inclusion criteria for this review. In 1 study, small bowel feeding was associated with a reduction in gastroesophageal regurgitation and a trend toward reduced pulmonary aspiration. Several studies document that small bowel feeding was associated with an increase in protein and calories delivered and a shorter time to target dose of nutrition. Compared with gastric feeding, when the results of 7 randomized trials were aggregated statistically, small bowel feeding was associated with a reduction in pneumonia (relative risk, 0.76; 95% confidence intervals, 0.59, 0.99). There was no difference in mortality rates between the 2 groups.

CONCLUSIONS

Small bowel feeding may be associated with a reduction in gastroesophageal regurgitation, an increase in nutrient delivery, a shorter time to achieve desired target nutrition, and a lower rate of ventilator-associated pneumonia.

Relationship between hospital infection and long-term mortality in general surgery: a prospective follow-up study

A prospective study of 1431 patients admitted to a general surgery department were followed up for a median of 6.2 years after discharge (7679 person-years of follow-up). We collected information on underlying conditions, including severity of illness, and healthcare-related variables. Relative rates of death and their 95% confidence interval (CI) were estimated using person-years as the denominator. Multiple-risk factors adjusted for relative rates (RR) were obtained using Poisson regression analysis. There were 172 deaths during the follow-up period after hospital discharge (2/100 person-years). Follow-up was complete in 91% of the cohort. There were no important differences in demographic characteristics or risk factors between patients followed up and those lost to follow-up. The death rate in patients with any hospital-acquired infection was 5.3/100 person-years, and the relative rate was 3.07 (95% CI: 2.20-4.24). After adjusting for the main predictors of mortality, we found an effect modification by the presence of chronic disease (P = 0.01 for the product-term between hospital infection and the diagnosis of chronic diseases). Among patients without any underlying chronic disease, hospital-acquired infection was related to a significantly higher long-term mortality (RR = 2.47, 95% CI: 1.24-4.91). In these patients, surgical wound infection yielded a RR of mortality of 3.44 (95% CI: 1.63-7.27). Among patients with underlying chronic disease no association between hospital infection and long-term mortality was found. No evidence of an important modification of the relative rate along the follow-up period was observed. In conclusion surgical patients without chronic disease developing hospital-acquired infection have an increased risk of long-term mortality.

Prevention of ventilator-associated pneumonia: Current practice in Canadian intensive care units

OBJECTIVE

To evaluate the current use of strategies to prevent ventilator-associated pneumonia (VAP) and to identify interventions to target for quality-improvement initiatives.

DESIGN

Cross-sectional national survey.

SETTING

Canadian intensive care units (ICUs) with at least 8 beds.

PATIENTS

Seven hundred and two patients in 66 ICUs in 10 provinces in Canada.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

The Canadian Critical Care Trials Group recently developed VAP prevention guidelines. Before these guidelines were disseminated, we documented the extent to which these recommendations were followed in practice by using 3 methods: survey of ICU directors, prospective observation of patients on one day, and retrospective review of patient charts for a 12-day period. According to ICU directors, ventilator circuits were changed only for new patients or if the circuit was soiled in 7 of 66 ICUs (10%), heat and moisture exchangers were used routinely in 53 of 66 ICUs (80%), and closed-suction catheter systems were used in 58 of 66 ICUs (88%). Neither subglottic secretion drainage tubes nor prophylactic antibiotics for VAP were used at all. Of the entire cohort of 702 patients, the average degree of elevation of the head of the bed was 29.9 degrees (range, 0 degrees -90 degrees ) and 22 of 702 (3.1%) were observed to be on a kinetic bed. Of the 459 patients receiving any form of mechanical ventilation, 56 (12.2%) were receiving noninvasive or mask ventilation, 262 (57.1%) were orally intubated, 9 (1.9%) were nasally intubated, and 132 (28.8%) had received a tracheostomy. Of the 423 patients who received nutrition support, 373 (88.2%) received enteral nutrition. Small bowel feeding tubes were used during 16.4% of study days on enteral feeds and sucralfate was prescribed for 1.7% of study days.

CONCLUSIONS

Significant opportunities exist to improve VAP prevention practices in Canada. These strategies include decreasing the frequency of ventilator circuit changes, and increasing the use of non-invasive ventilation, subglottic secretion drainage endotracheal tubes, kinetic bed therapy, small bowel feedings, and elevation of the head of the bed.

Influence on outcome of ventilator-associated pneumonia in multiple trauma patients with head trauma treated with selected digestive decontamination

OBJECTIVE

Ventilator-associated pneumonia is said to be associated with an increased mortality or a prolonged intensive care unit stay. In multiple trauma, the use of selective digestive decontamination has been reported to decrease morbidity and mortality associated with pneumonia. We performed a study to evaluate the attributable morbidity and mortality of ventilator-associated pneumonia in multiple trauma patients with head trauma treated with selective digestive decontamination.

DESIGN

Prospective, matched-paired, case-control study.

SETTING

Intensive care unit at a tertiary university hospital.

PATIENTS

During a 6-yr period, 324 consecutive multiple trauma patients with head trauma requiring mechanical ventilation for >48 hrs were prospectively followed for the development of VAP. Case-control matching criteria were as follows: 1) age difference within 5 yrs, 2) Glasgow coma scale within five categories, 3) injury severity score within 5 points, 4) APACHE II score within 5 points, 5) ventilation of control patients for at least as long as the cases. The selective digestive decontamination regimen was used in all patients (cases and controls): polymixin E, gentamicin, and amphotericin B. Systemic cefazolin (1 g three times a day) was given for the first 3 days of intensive care unit stay.

MEASUREMENTS AND MAIN RESULTS

Analysis was performed on 58 pairs that were matched with 100% of success The most common isolates recovered were Staphylococcus aureus (39%) and Haemophilus influenzae (22%). High-risk pathogens were rarely isolated: Pseudomonas aeruginosa (5.1%), Acinetobacter species (8.6%), and methicillin-resistant S. aureus (6.7%). The duration of mechanical ventilation and intensive care unit stay were increased in case patients (11.6 +/- 1.7 and 22.7 +/- 2.9 days, respectively) compared with control patients (9.4 +/- 1.3 and 16.8 +/- 2.9 days, respectively; p <.0006). Mortality was similar in both case (17%) and control (24%) patients.

CONCLUSION

Ventilator-associated pneumonia did not seem to increase mortality of multiple trauma patients with head trauma who received selective digestive decontamination. Whether or not this conclusion applied to trauma patients not receiving selective digestive decontamination should be evaluated in further studies.

Inadequate therapy and antibiotic resistance. Risk factors for mortality in the intensive care unit

BACKGROUND

The impact of nosocomial infections and multidrug resistance on mortality is a topic of considerable controversy.

METHODS

A prospective, nested case control study was conducted in four intensive care units (ICUs) in Mexico to measure the impact of antibiotic resistance on and identify the main risk factors for mortality in critically ill patients with nosocomial infections.

RESULTS

One hundred thirteen patients developed 119 nosocomial infections. Multivariate analysis identified two variables that were significantly and independently associated with mortality: ventilator-associated pneumonia (p = 0.0041, odds ratio [OR] = 7.7) and inadequate antibiotic treatment (p <0.0001, OR = 70.5). Although antibiotic resistance in Gram-negative rods was not an independent risk factor for mortality, there was a strong association between antibiotic resistance and inadequate treatment (chi2 for linear trend = 29.3, p <0.00001). For patients with ventilator-associated pneumonia, predicted mortality calculated by APACHE II score was 23% compared to an observed mortality of 71%.

CONCLUSIONS

In this study the major risk factors for mortality were inadequate antibiotic treatment and development of ventilator-associated pneumonia. Multidrug resistance significantly increased the probability of receiving inadequate antibiotic treatment. The striking differences between observed and predicted mortality in these four ICUs indicate the need for further research and a reassessment of the current programs for prevention and control of nosocomial infections in Mexico.

Blood culturing practices in a trauma intensive care unit: does concurrent antibiotic use make a difference?

BACKGROUND

Febrile trauma patients have repeated blood cultures drawn during a prolonged hospitalization. We examined the diagnostic yield of blood cultures in severely injured patients to determine whether concurrent antimicrobial therapy or prophylactic administration of antibiotics affects blood culture growth. We also determined how rapidly growth changed to determine whether total numbers of blood cultures could be decreased. The hypotheses of the study were that concurrent antimicrobial administration affects blood culture yield, prophylactic administration alters the culture result, and repetitive culturing is unnecessary.

METHODS

A retrospective chart review of trauma patients with minimum Injury Severity Score of 15 and minimum 5-day intensive care unit length of stay was performed. The dates and results of blood cultures and antibiotic type and administration dates were recorded. "Prophylactic" antibiotics were defined as antibiotics administered on admission to the unit. Computer software was used to match the blood culture date to the period of antimicrobial administration. Categorical data were compared using Fisher's exact test.

RESULTS

Two hundred fifty-eight patients met entry criteria, and 208 charts were complete for review. One hundred twenty-nine patients had 347 sets of blood cultures drawn. The positive blood culture rate was 10.8% in patients off antibiotics, and 13.9% in patients on antibiotics (p = 0.68). All prophylactic antibiotics included a beta-lactam. Only 18% of positive blood cultures in patients receiving prophylactic antibiotics were sensitive to beta-lactams as opposed to 59% sensitivity in those who did not receive prophylaxis (p = 0.03). One hundred seventy-six sets of blood cultures were performed after an initial positive culture. Only three patients with an initial positive culture had a second positive culture with a different organism. The mean time to culturing a new organism after initial growth was 19 days.

CONCLUSION

Concurrent antimicrobial administration does not alter blood culture yield. Prophylactic administration alters the type of organism cultured. Little new information is gained from repetitive culturing.

Infectious disease consultation and microbiologic surveillance for intensive care unit trauma patients: a pilot study

Infection remains a major cause of posttrauma morbidity. We retrospectively reviewed 2 cohorts of trauma patients admitted to a regional trauma center before and after a policy change integrating prospective microbiologic surveillance and infectious disease (ID) consultation into management of trauma admissions. Primary interests were effects of this policy change on antimicrobial use and diagnostic precision (particularly differentiation of infection from colonization). Associated costs, microflora, survival, and disability were also compared. Patients were stratified for risk of infection. ID consultation was associated with a 49% increased odds that an infection diagnosis was microbiologically based (P=.006) and 57% reduction of antibiotics costs per hospitalized day (P=.0008). Costs of consultation and an 86% increase (P<10(-6)) in total cultures combined to minimally exceed that financial saving. The observed improvements in diagnostic precision and antimicrobial usage, however, suggest consideration of prospective microbiologic surveillance and multidisciplinary physician teams including ID physicians for high-risk trauma patients.

Infection control in the ICU

Nosocomial infections (NIs) now concern 5 to 15% of hospitalized patients and can lead to complications in 25 to 33% of those patients admitted to ICUs. The most common causes are pneumonia related to mechanical ventilation, intra-abdominal infections following trauma or surgery, and bacteremia derived from intravascular devices. This overview is targeted at ICU physicians to convince them that the principles of infection control in the ICU are based on simple concepts and that the application of preventive strategies should not be viewed as an administrative or constraining control of their activity but, rather, as basic measures that are easy to implement at the bedside. A detailed knowledge of the epidemiology, based on adequate surveillance methodologies, is necessary to understand the pathophysiology and the rationale of preventive strategies that have been demonstrated to be effective. The principles of general preventive measures such as the implementation of standard and isolation precautions, and the control of antibiotic use are reviewed. Specific practical measures, targeted at the practical prevention and control of ventilator-associated pneumonia, sinusitis, and bloodstream, urinary tract, and surgical site infections are detailed. Recent data strongly confirm that these strategies may only be effective over prolonged periods if they can be integrated into the behavior of all staff members who are involved in patient care. Accordingly, infection control measures are to be viewed as a priority and have to be integrated fully into the continuous process of improvement of the quality of care.

Proportion of hospital deaths potentially attributable to nosocomial infection

OBJECTIVE

To determine the fraction of hospital deaths potentially associated with nosocomial infection (NI).

DESIGN

A matched (1:1) case-control study.

SETTING

An 800-bed, tertiary-care, teaching hospital.

PATIENTS

All patients older than 14 years who were admitted to the hospital between January 1, 1990, and January 1, 1991, were eligible. All 524 consecutive deaths that occurred in the hospital comprised the case group. For each case, a control patient was matched for primary admission diagnosis and admission date.

OUTCOME MEASURES

The proportion of hospital deaths potentially associated with NI was estimated from the population attributable risk (PAR) adjusted for age, gender, service, severity of illness, length of stay, and quality of the medical record.

RESULTS

For stays longer than 48 hours, the PAR for all NIs was estimated to be 21.3% (95% confidence interval [CI95], 16.8%-30.5%). The greatest proportion of deaths potentially associated with NIs was observed in patients with only one infection (PAR, 15.0%; CI95, 10.9%-22.6%) and bacteremia or sepsis (PAR, 7.7%; CI95, 4.6%-11.6%).

CONCLUSIONS

NIs are associated with a large proportion of intrahospital deaths. This information may help clinicians and healthcare managers to assess the impact of programs for the prevention and control of NIs on intrahospital death.

Colonization with methicillin-resistant Staphylococcus aureus in ICU patients: morbidity, mortality, and glycopeptide use

OBJECTIVE

To determine the impact of methicillin-resistant Staphylococcus aureus (MRSA) colonization on the occurrence of S. aureus infections (methicillin-resistant and methicillin-susceptible), the use of glycopeptides, and outcome among intensive care unit (CU) patients.

DESIGN

Prospective observational cohort survey.

SETTING

A medical-surgical ICU with 10 single-bed rooms in a 460-bed, tertiary-care, university-affiliated hospital.

PATIENTS

A total of 1,044 ICU patients were followed for the detection of MRSA colonization from July 1, 1995, to July, 1 1998.

METHODS

MRSA colonization was detected using nasal samples in all patients plus wound samples in surgical patients within 48 hours of admission or within the first 48 hours of ICU stay and weekly thereafter. MRSA infections were defined using Centers for Disease Control and Prevention standard definitions, except for ventilator-associated pneumonia and catheter-related infections, which were defined by quantitative distal culture samples.

RESULTS

One thousand forty-four patients (70% medical patients) were included in the analysis. Mean age was 61+/-18 years; mean Simplified Acute Physiologic Score (SAPS) II was 36.4+/-20; and median ICU stay was 4 (range, 1-193) days. Two hundred thirty-one patients (22%) died in the ICU. Fifty-four patients (5.1%) were colonized with MRSA on admission, and 52 (4.9%) of 1,044 acquired MRSA colonization in the ICU. Thirty-five patients developed a total of 42 S. aureus infections (32 MRSA, 10 methicillin-susceptible). After factors associated with the development of an S. aureus infection were adjusted for in a multivariate Cox model (SAPS II >36: hazard ratio [HR], 1.64; P=.09; male gender: HR, 2.2; P=.05), MRSA colonization increased the risk of S. aureus infection (HR, 3.84; P=.0003). MRSA colonization did not influence ICU mortality (HR, 1.01; P=.94). Glycopeptides were used in 11.4% of the patients (119/1,044) for a median duration of 5 days. For patients with no colonization, MRSA colonization on admission, and ICU-acquired MRSA colonization, respectively, glycopeptide use per 1,000 hospital days was 37.7, 235.2, and 118.3 days. MRSA colonization per se increased by 3.3-fold the use of glycopeptides in MRSA-colonized patients, even when an MRSA infection was not demonstrated, compared to non-colonized patients.

CONCLUSIONS

In our unit, MRSA colonization greatly increased the risk of S. aureus infection and of glycopeptide use in colonized and non-colonized patients, without influencing ICU mortality. MRSA colonization influenced glycopeptide use even if an MRSA infection was not demonstrated; thus, an MRSA control program is warranted to decrease vancomycin use and to limit glycopeptide resistance in gram-positive cocci.

A European perspective on nosocomial urinary tract infections II. Report on incidence, clinical characteristics and outcome (ESGNI-004 study). European Study Group on Nosocomial Infection

OBJECTIVES

To estimate the incidence of nosocomially acquired urinary tract infections (NAUTI) in Europe and provide information on the clinical characteristics, underlying conditions, etiology, management and outcome of patients.

MATERIALS AND METHODS

We collected clinical information from NAUTI patients with a microbiology report on the named study day.

RESULTS

A total of 141 hospitals from 25 European countries participated in the study. Written institutional bladder catheter guidelines were in place in 90.3% of EU hospitals and 55% of non-EU hospitals (P < 0.05). The total number of new NAUTI episodes on the day of the study was 298, representing an incidence of 3.55 episodes/1000 patient-days and an estimated prevalence of 10.65/1000. The five most commonly isolated micro-organisms were Escherichia coli, Enterococcus sp., Candida sp., Klebsiella sp. and Pseudomonas aeruginosa. Patients from non-EU countries were younger, with more severe underlying diseases with a higher incidence of obstructive uropathy/lithiasis. Overall, 22.8% of patients had no 'classic' UTI-predisposing factors. Catheter-associated UTI (CAUTI) was present in 187 patients (62.8%). A closed drainage system was used in only 78.5% of catheterised patients. The indication for bladder catheterisation was not considered adequate in 7.6% of cases and continuation of bladder catheterisation was considered unnecessary in 31.3%. Opening of the closed drainage system was the most frequent major error in catheter management (16.8%). Antimicrobial treatment was not considered adequate in 19.8% of all cases.

CONCLUSIONS

The incidence of NAUTI in a large European population is 3.55/1000 patient-days. There is clearly room for improvement in the area of bladder catheterisation, catheter care and medical management of NAUTI. We recommend that European authorities draw up and implement practical and specific guidelines to reduce the incidence of this infection.

Case-based reasoning for antibiotics therapy advice: an investigation of retrieval algorithms and prototypes

We have developed an antibiotics therapy advice system called ICONS for patients in an intensive care unit (ICU) who have caught an infection as additional complication. Since advice for such critically ill patients is needed very quickly and as the actual pathogen still has to be identified by the laboratory, we use an expected pathogen spectrum based on medical background knowledge and known resistances. The expected pathogen spectra and the resistance information are periodically updated from laboratory results. To speed up the process of finding suitable therapy recommendations, we have applied case-based reasoning (CBR) techniques. As all required information should always be up to date in medical expert systems, new cases should be incrementally incorporated into the case base and outdated ones should be updated or erased. For reasons of space limitations and of retrieval time an indefinite growth of the case base should be avoided. To fulfill these requirements we propose that specific single cases should be generalised to more general prototypical ones and that subsequent redundant cases should be erased. In this paper, we present evaluation results of different generation strategies for generalised cases (prototypes). Additionally, we compare measured retrieval times for two indexing retrieval algorithms: simple indexing, which is appropriate for small and medium case bases, and tree-hash retrieval, which is advantageous for large case bases.

Morbidity and mortality associated with surgical site infections: results from the 1997-1999 INCISO surveillance

Since 1997, a surgical-site infections (SSI) surveillance network (INCISO) has been implemented in volunteer general surgical units in Northern France. For three months each year, all patients who undergo a surgical procedure are consecutively reviewed for their peri-operative condition and traced for outcome with a 30-day follow-up. Of the 38973 surgical patients included over a three-year period, 1344 (3.4%) developed SSI and 568 died (1.5%) including 78 with an SSI. Organ-space and deep incisional SSI were associated with a higher mortality and required re-operation more frequently than did superficial incisional SSI. SSI incidence and mortality varied according to the surgical procedure. SSI was a significant predictor of mortality, independently of NNIS risk index and other survival predictors. Thirty-eight percent of deaths in SSI patients were attributable to infection. Hence, the significant impact of SSI on mortality and morbidity in surgical patients is now an additional reason to reinforce compliance of surgical staff with preventive measures and hygiene practices.

Effect of postpyloric feeding on gastroesophageal regurgitation and pulmonary microaspiration: results of a randomized controlled trial

OBJECTIVE

To determine the extent to which postpyloric feeding reduces gastroesophageal regurgitation and pulmonary microaspiration in critically ill patients.

DESIGN

Randomized trial.

SETTING

A medical/surgical intensive care unit at a tertiary care hospital.

PARTICIPANTS

Intensive care unit patients were expected to remain ventilated >72 hrs. We excluded patients with esophageal, gastric, or small bowel surgery in the last week and patients with overt or clinically significant gastrointestinal bleeding. We studied 33 patients; 42.4% were female, mean age (sd) was 59.2 (+/- 16.8) yrs, and mean Acute Physiology and Chronic Health Evaluation II score was 22.5 (7.8).

INTERVENTIONS

Patients were randomized to gastric or postpyloric enteral feeds. Technetium 99-sulphur colloid was added to the feeds for 6 hrs of each of the first 3 days on study.

MEASUREMENTS AND RESULTS

We sampled the oropharynx and trachea hourly for the 6 hrs per day that patients received radioisotope-labeled enteral feeds, and the level of radioactivity in these specimens was measured. We defined an episode of gastroesophageal regurgitation and microaspiration as an increase in radioactivity >100 counts per minute/g. Patients fed into the stomach had more episodes of gastroesophageal regurgitation (39.8% vs. 24.9%, p =.04) and trended toward more microaspiration (7.5% vs. 3.9%, p =.22) compared with patients fed beyond the pylorus. When the logarithmic mean of the radioactivity count was compared across groups, there was a trend toward an increase in gastroesophageal regurgitation (3.7 vs. 2.9 counts/g, p =.22) and a trend toward increased microaspiration (1.9 vs. 1.4 counts/g, p =.09) in patients fed into the stomach. Patients who had gastroesophageal regurgitation were much more likely to aspirate than patients who did not have gastroesophageal regurgitation (odds ratio: 3.2; 95% confidence interval: 1.36, 7.77).

CONCLUSIONS

Feeding beyond the pylorus is associated with a significant reduction in gastroesophageal regurgitation and a trend toward less microaspiration.

Pneumonia after cardiac surgery is predictable by tracheal aspirates but cannot be prevented by prolonged antibiotic prophylaxis

BACKGROUND

The purpose of this study was to assess the value of tracheal aspirate as a predictor of pneumonia after coronary artery bypass grafting and to evaluate the efficacy of prolonged perioperative antibiotic prophylaxis.

METHODS

Tracheal aspirates of 500 patients undergoing coronary artery bypass grafting were taken immediately after intubation and analyzed for microorganisms by Gram stain and semiquantitative microbiologic cultures. All patients received 2 g ceftriaxone as a single-dose perioperative antibiotic prophylaxis before operation. Results of Gram stains were available before the patients were transferred to the intensive care unit. After the results were known, both groups of patients (positive Gram stain, group 1; negative Gram stain, group 2) were randomly assigned to either conventional antibiotic prophylaxis (A), consisting of ceftriaxone 2 g on postoperative day 1, or prolonged antibiotic prophylaxis (B), with ticarcillin + clavulanic acid 3 x 5.2 g during 72 hours.

RESULTS

From 500 patients, 91 had a positive Gram stain whereas 409 had a negative one. The incidence of pneumonia was significantly higher in patients with preoperative positive tracheal aspirates (15.3%) than in patients with a negative one (3.6%; p < 0.01). However, prolonged prophylaxis did not reduce the rate of postoperative pneumonia, which was as high as 13% in untreated positive patients versus 17% in treated positive patients, and 2% in untreated negative patients versus 4% in treated patients. In patients who had pneumonia, there was a high correlation between the microorganisms found in preoperative aspirates and those observed when aspirates were repeated (100% correlation in patients with conventional antibiotic prophylaxis and 87% in those with prolonged prophylaxis).

CONCLUSIONS

Early postoperative pneumonia (<7 days) is most likely caused by microorganisms that colonize the respiratory tract before operation. The risk of pulmonary infection after coronary artery bypass grafting can be predicted from the preoperative tracheal aspirates. Prolonged perioperative antibiotic prophylaxis has no efficacy in reducing the incidence of pulmonary infections.

A multi-state model for evolution of intensive care unit patients: prediction of nosocomial infections and deaths

Nosocomial (hospital-acquired) infections are very frequent in intensive care units (ICU). The risk of death after severe infection is high, but the precise rate of death in ICU attributable to nosocomial infection is not known. The goal of this project was to build a statistical model to predict the occurrence of nosocomial infections in ICU and the outcome of the patients. We collected data on 676 consecutive patients admitted to an ICU for more than 24 hours between 1993 and 1996. The following data were collected for each patient: history; clinical examination at entry; subsequent infections; outcome. A multi-state heterogeneous semi-Markov model was determined and then validated; the initial data set was randomly split into two groups: two-thirds (450 patients) to build the model and one-third (226 patients) to validate it. The model defined five states: ICU admission; first simple infection; first complicated infection; death, and discharge from the ICU. Transitions between these states determined nine different events. The global model of patient histories can be divided into nine survival models, each corresponding to one of these events. The possible events from a given state were considered to be competing. Since many risk factors induced non-proportional hazard functions, piecewise exponential models were used to model event occurrence. The effect of continuous covariates on hazard functions has been described with a non-parametric method that enables non-linear relations to be shown. Among other things, the model allows patients' post-admission histories to be predicted from data available at ICU admission. The bootstrap estimator of the attributable risk of death due to simple or complicated nosocomial infections is 44.2 percent (95 percent CI 26.0-61.6 percent). We were also able to characterize the most highly exposed patients, those who comprise the high-risk group on whom prevention efforts must be focused.

Nosocomial infections in combined medical-surgical intensive care units in the United States

OBJECTIVE

To describe the epidemiology of nosocomial infections in combined medical-surgical (MS) intensive care units (ICUs) participating in the National Nosocomial Infection Surveillance (NNIS) System.

DESIGN

Analysis of surveillance data on 498,998 patients with 1,554,070 patient-days, collected between 1992 and 1998 from 205 MS ICUs following the NNIS Intensive Care Unit protocol, representing 152 participating NNIS hospitals in the United States.

RESULTS

Infections at three major sites represented 68% of all reported infections (nosocomial pneumonia, 31%; urinary tract infections (UTIs), 23%; and primary bloodstream infections (BSIs), 14%: 83% of episodes of nosocomial pneumonia were associated with mechanical ventilation, 97% of UTIs occurred in catheterized patients, and 87% of primary BSIs in patients with a central line. In patients with primary BSIs, coagulase-negative staphylococci (39%) were the most common pathogens reported; Staphylococcus aureus (12%) was as frequently reported as enterococci (11%). Coagulase-negative staphylococcal BSIs were increasingly reported over the 6 years, but no increase was seen in candidemia or enterococcal bacteremia. In patients with pneumonia, S. aureus (17%) was the most frequently reported isolate. Of reported isolates, 59% were gram-negative bacilli. In patients with UTIs, Escherichia coli (19%) was the most frequently reported isolate. Of reported isolates, 31% were fungi. In patients with surgical-site infections, Enterococcus (17%) was the single most frequently reported pathogen. Device-associated nosocomial infection rates for BSIs, pneumonia, and UTIs did not correlate with length of ICU stay, hospital bed size, number of beds in the ICU, or season. Combined MS ICUs in major teaching hospitals had higher device-associated infection rates compared to all other hospitals with combined medical-surgical units.

CONCLUSIONS

Nosocomial infections in MS ICUs at the most frequent infection sites (bloodstream, urinary, and respiratory tract) almost always were associated with use of an invasive device. Device-associated infection rates were the best available comparative rates between combined MS ICUs, but the distribution of device-associated rates should be stratified by a hospital's major teaching affiliation status.

Fever in the ICU

Fever is a common problem in ICU patients. The presence of fever frequently results in the performance of diagnostic tests and procedures that significantly increase medical costs and expose the patient to unnecessary invasive diagnostic procedures and the inappropriate use of antibiotics. ICU patients frequently have multiple infectious and noninfectious causes of fever, necessitating a systematic and comprehensive diagnostic approach. Pneumonia, sinusitis, and blood stream infection are the most common infectious causes of fever. The urinary tract is unimportant in most ICU patients as a primary source of infection. Fever is a basic evolutionary response to infection, is an important host defense mechanism and, in the majority of patients, does not require treatment in itself. This article reviews the common infectious and noninfectious causes of fever in ICU patients and outlines a rational approach to the management of this problem.

APACHE II and ISS scores as predictors of nosocomial infections in trauma patients

BACKGROUND

Nosocomial infections affect more than 2 million patients annually in the United States at a cost of $4.5 billion. The aim of this study is to identify the role of the APACHE II score and the Injury Severity Scale (ISS) as independent predictors of nosocomial infections in trauma patients admitted to the intensive care unit (ICU).

METHODS

A retrospective chart review of 113 trauma patients admitted to the ICU was conducted by an infectious disease physician. Demographic data and incidence of nosocomial infections were recorded. Multivariate logistic regression analysis was used to determine variables that are predictive of the occurrence of nosocomial infections.

RESULTS

Presence or absence of intubation, ICU length of stay, APACHE II score, and ISS were related to the presence of infections; however, only the ICU length of stay was an independent predictor of a nosocomial infection, with an odds ratio of 1.81. By linear regression, 17% of the variance in the ICU duration of stay was a result of the APACHE II score in patients with a score >/=5.

CONCLUSION

APACHE II score and ISS score were not good predictors of the incidence of nosocomial infections in trauma patients admitted to the ICU, but the APACHE II score has a modest correlation with the duration of stay in the ICU. A stratified cohort study could identify the subset of patients for which the APACHE II score predicts a prolonged stay in the ICU, thus an increased risk of infection.

The attributable morbidity and mortality of ventilator-associated pneumonia in the critically ill patient. The Canadian Critical Trials Group

To evaluate the attributable morbidity and mortality of ventilator-associated pneumonia (VAP) in intensive care unit (ICU) patients, we conducted a prospective, matched cohort study. Patients expected to be ventilated for > 48 h were prospectively followed for the development of VAP. To determine the excess ICU stay and mortality attributable to VAP, we matched patients with VAP to patients who did not develop clinically suspected pneumonia. We also conducted sensitivity analyses to examine the effect of different populations, onset of pneumonia, diagnostic criteria, causative organisms, and adequacy of empiric treatment on the outcome of VAP. One hundred and seventy-seven patients developed VAP. As compared with matched patients who did not develop VAP, patients with VAP stayed in the ICU for 4.3 d (95% confidence interval [CI]: 1.5 to 7. 0 d) longer and had a trend toward an increase in risk of death (absolute risk increase: 5.8%; 95% CI: -2.4 to 14.0 d; relative risk (RR) increase: 32.3%; 95% CI: -20.6 to 85.1%). The attributable ICU length of stay was longer for medical than for surgical patients (6. 5 versus 0.7 d, p < 0.004), and for patients infected with "high risk" organisms as compared with "low risk" organisms (9.1 d versus 2.9 d). The attributable mortality was higher for medical patients than for surgical patients (RR increase of 65% versus -27.3%, p = 0. 04). Results were similar for three different VAP diagnostic criteria. We conclude that VAP prolongs ICU length of stay and may increase the risk of death in critically ill patients. The attributable risk of VAP appears to vary with patient population and infecting organism.