Epidemiology and risk factors for nosocomial pneumonia. Emphasis on prevention

Variable Definitions: Implications for the Prediction of Pulmonary Complications after Adult Cardiac Surgery

AIM

The aim of this paper was to review the implications that variable definitions have for the prediction of post-operative pulmonary complications after cardiac surgery.

METHOD

A review of the literature from 1980 to 2002. Selected studies demonstrated an original attempt to examine multivariate associations between pre, intra or post-operative antecedents and pulmonary outcomes in patients undergoing coronary artery bypass grafting (CABG). Reports that described the validation of established clinical prediction rules, testing interventions or research conducted in non-human cohorts were excluded from this review.

RESULTS

Consistently, variable factor and outcome definitions are combined for the development of multivariate prediction models that subsequently have limited clinical value. Despite being prevalent there are very few attempts to examine post-operative pulmonary complications (PPC) as endpoints in isolation. The trajectory of pulmonary dysfunction that precedes complications in the post-operative context is not clear. As such there is little knowledge of post-operative antecedents to PPC that are invariably excluded from model development.

CONCLUSION

Multivariate clinical prediction rules that incorporate antecedent patient and process factors from the continuum of cardiovascular care for specific pulmonary outcomes are recommended. Models such as these would be useful for practice, policy and quality improvement.

Nosocomial pneumonia : rationalizing the approach to empirical therapy

Nosocomial pneumonia or hospital-acquired pneumonia (HAP) causes considerable morbidity and mortality. It is the second most common nosocomial infection and the leading cause of death from hospital-acquired infections. In 1996 the American Thoracic Society (ATS) published guidelines for empirical therapy of HAP. This review focuses on the literature that has appeared since the ATS statement. Early diagnosis of HAP and its etiology is crucial in guiding empirical therapy. Since 1996, it has become clear that differentiating mere colonization from etiologic pathogens infecting the lower respiratory tract is best achieved by employing bronchoalveolar lavage (BAL) or protected specimen brush (PSB) in combination with quantitative culture and detection of intracellular microorganisms. Endotracheal aspirate and non-bronchoscopic BAL/PSB in combination with quantitative culture provide a good alternative in patients suspected of ventilator-associated pneumonia. Since culture results take 2–3 days, initial therapy of HAP is by definition empirical. Epidemiologic studies have identified the most frequently involved pathogens: Enterobacteriaceae, Haemophilus influenzae, Streptococcus pneumoniae and Staphylococcus aureus (‘core pathogens’). Empirical therapy covering only the ‘core pathogens’ will suffice in patients without risk factors for resistant microorganisms. Studies that have appeared since the ATS statement issued in 1996, demonstrate several new risk factors for HAP with multiresistant pathogens. In patients with risk factors, empirical therapy should consist of antibacterials with a broader spectrum. The most important risk factors for resistant microorganisms are late onset of HAP (≥5 days after admission), recent use of antibacterial therapy, and mechanical ventilation. Multiresistant bacteria of specific interest are methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, Acinetobacter calcoaceticus- baumannii, Stenotrophomonas maltophilia and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. Each of these organisms has its specific susceptibility pattern, demanding appropriate antibacterial treatment. To further improve outcomes, specific therapeutic options for multiresistant pathogens and pharmacological factors are discussed. Antibacterials developed since 1996 or antibacterials with renewed interest (linezolid, quinupristin/dalfopristin, teicoplanin, meropenem, new fluoroquinolones, and fourth-generation cephalosporins) are discussed in the light of developing resistance.

Since the ATS statement, many reports have shown increasing incidences of resistant microorganisms. Therefore, one of the most important conclusions from this review is that empirical therapy for HAP should not be based on general guidelines alone, but that local epidemiology should be taken into account and used in the formulation of local guidelines.

Silver-coated endotracheal tubes for prevention of ventilator-associated pneumonia in critically ill patients

BACKGROUND

Ventilator-associated pneumonia (VAP) is one of the most common nosocomial infections in intubated and mechanically ventilated patients. Endotracheal tubes (ETTs) appear to be an independent risk factor for VAP. Silver-coated ETTs slowly release silver cations. It is these silver ions that appear to have a strong antimicrobial effect. Because of this antimicrobial effect of silver, silver-coated ETTs could be an effective intervention to prevent VAP in people who require mechanical ventilation for 24 hours or longer.

OBJECTIVES

Our primary objective was to investigate whether silver-coated ETTs are effective in reducing the risk of VAP and hospital mortality in comparison with standard non-coated ETTs in people who require mechanical ventilation for 24 hours or longer. Our secondary objective was to ascertain whether silver-coated ETTs are effective in reducing the following clinical outcomes: device-related adverse events, duration of intubation, length of hospital and intensive care unit (ICU) stay, costs, and time to VAP onset.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014 Issue 10, MEDLINE, EMBASE, EBSCO CINAHL, and reference lists of trials. We contacted corresponding authors for additional information and unpublished studies. We did not impose any restrictions on the basis of date of publication or language. The date of the last search was October 2014.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) and quasi-randomized trials that evaluated the effects of silver-coated ETTs or a combination of silver with any antimicrobial-coated ETTs with standard non-coated ETTs or with other antimicrobial-coated ETTs in critically ill people who required mechanical ventilation for 24 hours or longer. We also included studies that evaluated the cost-effectiveness of silver-coated ETTs or a combination of silver with any antimicrobial-coated ETTs.

DATA COLLECTION AND ANALYSIS

Two review authors (GT, HV) independently extracted the data and summarized study details from all included studies using the specially designed data extraction form. We used standard methodological procedures expected by The Cochrane Collaboration. We performed meta-analysis for outcomes when possible.

MAIN RESULTS

We found three eligible randomized controlled trials, with a total of 2081 participants. One of the three included studies did not mention the amount of participants and presented no outcome data. The 'Risk of bias' assessment indicated that there was a high risk of detection bias owing to lack of blinding of outcomes assessors, but we assessed all other domains to be at low risk of bias. Trial design and conduct were generally adequate, with the most common areas of weakness in blinding. The majority of participants were included in centres across North America. The mean age of participants ranged from 61 to 64 years, and the mean duration of intubation was between 3.2 and 7.7 days. One trial comparing silver-coated ETTs versus non-coated ETTs showed a statistically significant decrease in VAP in favour of the silver-coated ETT (1 RCT, 1509 participants; 4.8% versus 7.5%, risk ratio (RR) 0.64, 95% confidence interval (CI) 0.43 to 0.96; number needed to treat for an additional beneficial outcome (NNTB) = 37; low-quality evidence). The risk of VAP within 10 days of intubation was significantly lower with the silver-coated ETTs compared with non-coated ETTs (1 RCT, 1509 participants; 3.5% versus 6.7%, RR 0.51, 95% CI 0.31 to 0.82; NNTB = 32; low-quality evidence). Silver-coated ETT was associated with delayed time to VAP occurrence compared with non-coated ETT (1 RCT, 1509 participants; hazard ratio 0.55, 95% CI 0.37 to 0.84). The confidence intervals for the results of the following outcomes did not exclude potentially important differences with either treatment. There were no statistically significant differences between groups in hospital mortality (1 RCT, 1509 participants; 30.4% versus 26.6%, RR 1.09, 95% CI 0.93 to 1.29; low-quality evidence); device-related adverse events (2 RCTs, 2081 participants; RR 0.65, 95% CI 0.37 to 1.16; low-quality evidence); duration of intubation; and length of hospital and ICU stay. We found no clinical studies evaluating the cost-effectiveness of silver-coated ETTs.

AUTHORS' CONCLUSIONS

This review provides limited evidence that silver-coated ETT reduces the risk of VAP, especially during the first 10 days of mechanical ventilation.

Alpha-1 antitrypsin reduces severity of pseudomonas pneumonia in mice and inhibits epithelial barrier disruption and pseudomonas invasion of respiratory epithelial cells

Nosocomial pneumonia (NP) is the third most common hospital-acquired infection and the leading cause of death due to hospital-acquired infection in the US. During pneumonia and non-pneumonia severe illness, respiratory tract secretions become enriched with the serine protease neutrophil elastase (NE). Several NE activities promote onset and severity of NP. NE in the airways causes proteolytic tissue damage, augments inflammation, may promote invasion of respiratory epithelium by bacteria, and disrupts respiratory epithelial barrier function. These NE activities culminate in enhanced bacterial replication, impaired gas exchange, fluid intrusion into the airways, and loss of bacterial containment that can result in bacteremia. Therefore, neutralizing NE activity may reduce the frequency and severity of NP. We evaluated human alpha-1 antitrypsin (AAT), the prototype endogenous NE inhibitor, as a suppressor of bacterial pneumonia and pneumonia-related pathogenesis. In AAT^+/+ transgenic mice that express human AAT in lungs, mortality due to Pseudomonas aeruginosa (P.aer) pneumonia was reduced 90% compared to non-transgenic control animals. Exogenous human AAT given to non-transgenic mice also significantly reduced P.aer pneumonia mortality. P.aer-infected AAT^+/+ mice demonstrated reduced lung tissue damage, decreased bacterial concentrations in lungs and blood, and diminished circulating cytokine concentrations compared to infected non-transgenic mice. In vitro, AAT suppressed P.aer internalization into respiratory epithelial cells and inhibited NE or P.aer-induced disruption of epithelial cell barrier function. The beneficial effects of human AAT in murine P.aer pneumonia raise the possibility of AAT use as a prophylactic treatment for NP in humans, and suggest a role for AAT as an innate immune mediator.

Antibiotic resistance patterns in medical and surgical patients in a combined medical-surgical intensive care unit

PURPOSE

Studies have found different rates of antimicrobial resistance among patients in medical and surgical intensive care units (ICUs). We studied whether these differences were a function of geography or differences in the patient populations, by comparing resistance rates among bacteria isolated from a combined medical/surgical ICU.

MATERIALS AND METHODS

We retrospectively evaluated the results of bacterial cultures of each patient admitted to the ICU between February 2005 and September 2006. Data collection included patient demographics and culture and sensitivity results. Intensive care unit populations were compared using the Fisher exact test and the Student t test.

RESULTS

One hundred seventy-one medical and 94 surgical patients with positive cultures were studied. Organisms were grouped into 4 classes: Staphylococcus aureus, nonlactose fermenting gram-negative bacilli, Enterococcus species, and gram-negative enteric bacteria. In the 4 classes, no significant difference in antibiotic resistance was found between medical and surgical patients.

CONCLUSION

Reported differences in resistance patterns among bacteria cultured from medical and surgical patients may be due to geographic separation of the ICUs as opposed to differences in the patient characteristics. This study suggests that ICU-specific antibiograms remain a useful tool to guide the choice of antimicrobial therapy, even in medical/surgical ICUs.

Clinical practice guidelines for hospital-acquired pneumonia and ventilator-associated pneumonia in adults

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) are important causes of morbidity and mortality, with mortality rates approaching 62%. HAP and VAP are the second most common cause of nosocomial infection overall, but are the most common cause documented in the intensive care unit setting. In addition, HAP and VAP produce the highest mortality associated with nosocomial infection. As a result, evidence-based guidelines were prepared detailing the epidemiology, microbial etiology, risk factors and clinical manifestations of HAP and VAP. Furthermore, an approach based on the available data, expert opinion and current practice for the provision of care within the Canadian health care system was used to determine risk stratification schemas to enable appropriate diagnosis, antimicrobial management and nonantimicrobial management of HAP and VAP. Finally, prevention and risk-reduction strategies to reduce the risk of acquiring these infections were collated. Future initiatives to enhance more rapid diagnosis and to effect better treatment for resistant pathogens are necessary to reduce morbidity and improve survival.

Appropriateness is critical

Inappropriate empirical antibiotic therapy for severe infections in the intensive care unit is a modifiable prognostic factor that has a great effect on patient outcome and health care resources. Inappropriate treatment is usually associated with microorganisms resistant to the common antibiotics, which must be empirically targeted when risk factors are present. Previous antibiotic exposure, prolonged length of hospital stay, admission category, local susceptibilities, colonization pressure, and the presence of invasive devices increase the likelihood of infection by resistant pathogens. Consideration of issues beyond in vitro susceptibility, such as antibiotic physicochemistry, tissue penetration, and pharmacokinetic/pharmacodynamic-driven dosing, is mandatory for the optimization of antibiotic use.

Strategies in the prevention of ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) remains a significant problem in the hospital setting, with very high morbidity, mortality, and cost. We performed an evidence-based review of the literature focusing on clinically relevant pharmacological and nonpharmacological interventions to prevent VAP. Owing to the importance of this condition the implementation of preventive measures is paramount in the care of mechanically ventilated patients. There is evidence that these measures decrease the incidence of VAP and improve outcomes in the intensive care unit. A multidisciplinary approach, continued education, and ventilator protocols ensure the implementation of these measures. Future research will continue to investigate cost/benefit relationships, antibiotic resistance, as well as newer technologies to prevent contamination and aspiration in mechanically ventilated patients.

Strategies to prevent ventilator-associated pneumonia in neonates

Ventilator-associated pneumonia (VAP) is one of the leading causes of preventable morbidity and mortality in neonatal intensive care units. This review examines the epidemiology and pathogenesis of VAP in neonates as well as the dilemmas faced by caregivers to diagnose and prevent VAP.

Nosocomial pneumonia: importance of the oral environment

Nosocomial pneumonia, especially ventilator-associated pneumonia, is a common infection in ICUs. The main etiologic factors involve colonizing and opportunistic bacteria from the oral cavity. Oral hygiene measures, including the use of oral antiseptic agents, such as chlorhexidine, have proven useful in reducing its incidence. The objective of this article was to review the literature on the importance of the oral environment in the development of nosocomial pneumonia.

Frequency of ventilator-associated pneumonia with 3-day versus 7-day ventilator circuit changes

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common clinical problem. Previous studies involving adult patient cohorts have assessed various risk factors associated with VAP, including ventilator circuit changes. The objective of this study was to examine the incidence of and risk factors associated with VAP, particularly 3-day versus 7-day ventilator circuit changes, in a pediatric intensive care unit (PICU).

METHODS

This was a cohort observational study. Patients hospitalized in the PICU at Chang Gung Children's Hospital between November 2003 and September 2004 were enrolled. Investigators and critical-care specialists evaluated baseline characteristics, incidence of VAP, and related variables from PICU admission until discharge or death.

RESULTS

Of 397 patients initially enrolled, 96 (aged 11-60 months) were available for statistical analysis and were assigned into two groups according to timing of ventilator circuit change: 3-day (n = 46) and 7-day circuit change (n = 50). No statistically significant differences were observed for VAP incidence (13% vs. 16%, p = 0.68) or hospital mortality (22% vs. 36%, p = 0.14) for 3-day versus 7-day circuit change. Incidence of VAP per 1000 ventilation days was 10.75 and 8.41 for 3-day and 7-day circuit change, respectively. Univariate analysis indicated statistical significance for the duration of mechanical ventilation (10.17 +/- 16.63 days vs. 18.20 +/- 14.99 days, p < 0.001), length of stay in PICU (22.30 +/- 20.48 days vs. 37.22 +/- 36.79 days, p = 0.0069) and presence of enteral nutrition [7 (15.22%) vs. 23 (46.0%), p = 0.0012].

CONCLUSION

Weekly circuit change does not contribute to increased rates of VAP in pediatric patients. Long-term studies evaluating risk factors in larger pediatric patient populations are warranted for further conclusive recommendations.

The impact of a simple, low-cost oral care protocol on ventilator-associated pneumonia rates in a surgical intensive care unit

OBJECTIVE

The purpose of this study was to determine the effects of a simple low-cost oral care protocol on ventilator-associated pneumonia rates in a surgical intensive care unit.

DESIGN

Preintervention and postintervention observational study.

SETTING

Twenty-four bed surgical/trauma/burn intensive care units in an urban university hospital.

PATIENTS

All mechanically ventilated patients that were admitted to the intensive care unit between June 1, 2004 and May 31, 2005.

INTERVENTIONS

An oral care protocol to assist in prevention of bacterial growth of plaque by cleaning the patients' teeth with sodium monoflurophosphate 0.7% paste and brush, rinsing with tap water, and subsequent application of a 0.12% chlorhexidine gluconate chemical solution done twice daily at 12-hour intervals.

MEASUREMENTS AND MAIN RESULTS

During the preintervention period from June 1, 2003 to May 31, 2004, there were 24 infections in 4606 ventilator days (rate = 5.2 infections per 1000 ventilator days). After the institution of the oral care protocol, there were 10 infections in 4158 ventilator days, resulting in a lower rate of 2.4 infections per 1000 ventilator days. This 46% reduction in ventilator-associated pneumonia was statistically significant (P = .04). Staff compliance with the oral care protocol during the 12-month period was also monitored biweekly and averaged 81%. The total cost of the oral care protocol was US$2187.49. There were 14 fewer cases of ventilator-associated pneumonia, which led to a decrease in cost of US$140 000 to US$560 000 based on the estimated cost per ventilator-associated pneumonia infection of US$10 000 to US$40 000. There was an overall reduction in ventilator-associated pneumonia without a change to the gram-negative or gram-positive microorganism profile.

CONCLUSIONS

The implementation of a simple, low-cost oral care protocol in the surgical intensive care unit led to a significantly decreased risk of acquiring ventilator-associated pneumonia.

Effectiveness of an Educational Program to Reduce Ventilator-Associated Pneumonia in a Tertiary Care Center in Thailand: A 4-Year Study

BACKGROUND

Ventilator-associated pneumonia (VAP) is considered to be an important cause of infection-related death and morbidity in intensive care units (ICUs). We sought to determine the long-term effect of an educational program to prevent VAP in a medical ICU (MICU).

METHODS

A 4-year controlled, prospective, quasi-experimental study was conducted in an MICU, surgical ICU (SICU), and coronary care unit (CCU) for 1 year before the intervention (period 1), 1 year after the intervention (period 2), and 2 follow-up years (period 3). The SICU and CCU served as control ICUs. The educational program involved respiratory therapists and nurses and included a self-study module with preintervention and postintervention assessments, lectures, fact sheets, and posters.

RESULTS

Before the intervention, there were 45 episodes of VAP (20.6 cases per 1000 ventilator-days) in the MICU, 11 (5.4 cases per 1000 ventilator-days) in the SICU, and 9 (4.4 cases per 1000 ventilator-days) in the CCU. After the intervention, the rate of VAP in the MICU decreased by 59% (to 8.5 cases per 1000 ventilator-days; P=.001) and remained stable in the SICU (5.6 cases per 1000 ventilator-days; P=.22) and CCU (4.8 cases per 1000 ventilator-days; P=.48). The rate of VAP in the MICU continued to decrease in period 3 (to 4.2 cases per 1000 ventilator-days; P=.07), and rates in the SICU and CCU remained unchanged. Compared with period 1, the mean duration of hospital stay in the MICU was reduced by 8.5 days in period 2 (P<.001) and by 8.9 days in period 3 (P<.001). The monthly hospital antibiotic costs of VAP treatment and the hospitalization cost for each patient in the MICU in periods 2 and 3 were also reduced by 45%-50% (P<.001) and 37%-45% (P<.001), respectively.

CONCLUSIONS

A focused education intervention resulted in sustained reductions in the incidence of VAP, duration of hospital stay, cost of antibiotic therapy, and cost of hospitalization.

Factors associated with mortality in critically injured trauma patients who require simultaneous cultures

BACKGROUND

In trauma patients surviving their initial injuries, infectious complications and multiple organ failure represent the major causes of death after the first 72 hours. Critically injured trauma patients frequently have bacteria recoverable simultaneously from multiple culture sites; the clinical significance of this event is unknown. The objective of this study was to identify the association between growth patterns of multiple site cultures and mortality among critically injured trauma patients.

METHODS

We performed a retrospective chart review collecting demographic and medical data on admissions to a state-designated Level I trauma center from April 2000 to December 2002. The inclusion criteria were age >17 years, admission to the trauma intensive care unit (TICU), and simultaneous sampling of blood, sputum, and urine in the setting of fever of undetermined origin or alteration in the white blood cell count. Four mutually exclusive groups were developed according to the number of positive culture sites. We used standard statistical analysis and multivariate logistic regression.

RESULTS

During the study period, 3,402 patients were admitted to the trauma service of whom 124 met the inclusion criteria. Eighty percent of these (99) were male, and the average age was 41 years. The median TICU stay was 17 days. The mortality rate was 24.2% (30 nonsurvivors). The survivors and non-survivors were comparable in injury severity score (ISS), initial base deficit, initial hematocrit, initial blood pressure, and hospital length of stay (p > 0.05), whereas age (p = 0.03), female sex (p = 0.04), and TICU stay (p < 0.01) were higher among non-survivors. More non-survivors showed growth of microorganisms in simultaneous blood, sputum, and urine cultures (p = 0.02). By multivariate analysis, adjusting for age, sex, and TICU length of stay, patients with growth of microorganisms in simultaneous cultures (blood, sputum, and urine) had a 3-fold greater mortality rate (OR, 3.20; 95% CI 1.05, 9.73).

CONCLUSIONS

In this group of patients, growth of bacteria in simultaneous cultures was associated with higher mortality-a factor that may be considered a poor prognostic indicator. This factor requires further studies to explore the relation with survival in critically injured patients.

Plan-do-study-act cycles as an instrument for improvement of compliance with infection control measures in care of patients after cardiothoracic surgery

The aim of this study was to determine whether compliance with infection control measures for the care of patients during and after cardiothoracic surgery could be improved by using 'plan-do-study-act' (PDSA) improvement cycles in a 715-bed university hospital. The endpoints of these cycles were indices of correct procedure based on infection control standards. The intervention consisted of instruction and training of nursing and medical staff on the use of PDSA cycles, feedback of the baseline measurements, and the use of posters in the proximity of the operating room (OR). At follow-up, overall compliance only improved in the room used by the perfusionists and the OR. After the follow-up period, monitoring revealed a drop in compliance in the OR, but improved compliance during vascular catheter care of patients with prolonged stay in the intensive care unit (ICU), and during wound care of patients on the nursing ward. The last series of monitoring showed that compliance with general infection control measures in the OR had improved again, and that compliance had remained satisfactory on the ward and in the ICU, with the exception of patients recently transferred to the ICU from the OR. The results show that by using PDSA cycles, compliance with infection control measures can improve significantly. However, repeated monitoring is necessary to ensure continued compliance.

The attributable cost and length of hospital stay because of nosocomial pneumonia in intensive care units in 3 hospitals in Argentina: a prospective, matched analysis

BACKGROUND

No information is available on the financial impact of nosocomial pneumonia in Argentina. To calculate the cost of nosocomial pneumonia in intensive care units, a 5-year, matched cohort study was undertaken at 3 hospitals in Argentina.

SETTING

Six adult intensive care units (ICU).

METHODS

Three hundred seven patients with nosocomial pneumonia (exposed) and 307 patients without nosocomial pneumonia (unexposed) were matched for hospital, ICU type, year admitted to study, length of stay more than 7 days, sex, age, antibiotic use, and average severity of illness score (ASIS). The patient's length of stay (LOS) in the ICU was obtained prospectively in daily rounds, the cost of a day was provided by the hospital's finance department, and the cost of antibiotics prescribed for nosocomial pneumonia was provided by the hospital's pharmacy department.

RESULTS

The mean extra LOS for 307 cases (compared with controls) was 8.95 days, the mean extra antibiotic defined daily doses (DDD) was 15, the mean extra antibiotic cost was $996, the mean extra total cost was $2255, and the extra mortality was 30.3%.

CONCLUSIONS

Nosocomial pneumonia results in significant patient morbidity and consumes considerable resources. In the present study, patients with nosocomial pneumonia had significant prolongation of hospitalization, cost, and a high extra mortality. The present study illustrates the potential cost savings of introducing interventions to reduce nosocomial pneumonia. To our knowledge, this is the first study evaluating this issue in Argentina.

Infection prophylaxis of gunshot wounds using probiotics

OBJECTIVE

To report a new method of surgical infection prophylaxis for postoperative gunshot wounds to the extremities.

METHOD

Gunshot wounded animals were divided into three groups: treatment (probiotic Sporobacterin), antibiotic (cephalosporin cefamezin) and control (no treatment). Histological studies of wound-bed tissue were taken on days 1, 3, 5 and 10 of the study.

RESULTS

The probiotic administered per os was more effective than antibiotics for prophylaxis of surgical infection.

CONCLUSION

The probiotic's effect is based on the natural defence mechanism activated after injury--the bacterial translocation of saprophytic bacteria from the gut to the wound.

DECLARATION OF INTEREST

None.

Risk factors for the development of pneumonia in acute psychotropic drugs poisoning

Background/Aim. Pneumonia is the most frequent complication in acute psychotropic drugs poisoning, which results in substantial morbidity and mortality, but which also increases the costs of treatment. Risk factors for pneumonia are numerous: age, sex, place of the appearance of pneumonia, severity of underlying disease, airway instrumentation (intubation, reintubation, etc). The incidence of pneumonia varies in poisoning caused by the various groups of drugs. The aim of this study was to determine the incidence and risk factors for pneumonia in the patients with acute psychotropic drugs poisoning. Methods. A group of 782 patients, out of which 614 (78.5%) with psychotropic and 168 (21.5%) nonpsychotropic drug poisoning were analyzed prospectively during a two-year period. The diagnosis of pneumonia was made according to: clinical presentation, new and persistent pulmonary infiltrates on chest radiography, positive nonspecific parameters of inflammation, and the microbiological confirmation of causative microorganisms. To analyze predisposing risk factors for pneumonia, the following variables were recorded: sex, age, underlying diseases, endotracheal intubation, coma, severity of poisoning with different drugs, histamine H2 blockers, corticosteroids, mechanical ventilation, central venous catheter. The univariate analysis for pneumonia risk factors in all patients, and for each group separately was done. The multivariate analysis was performed using the logistic regression technique. Results. Pneumonia was found in 94 (12.02%) of the patients, 86 of which (91.5%) in psychotropic and 8 (8.5%) in nonpsychotropic drug poisoning. In the psychotropic drug group, pneumonia was the most frequent in antidepressant (47%), and the rarest in benzodiazepine poisoning (3.8%). A statistically significant incidence of pneumonia was found in the patients with acute antidpressant poisoning (p < 0.001). Univariate analysis showed statistical significance for the following parameters: sex (p < 0.05), chronic alcohol intake (p < 0.05), underlying diseases (p < 0.01), central venous catheter (p < 0.05) vasopressors (p < 0.05), coma (p < 0.001), H2 blockers (p < 0.001) and corticosteroids (p < 0.001). The multivariate analysis retained endotracheal intubation and antidepressant drug poisoning as an independent risk factor for pneumonia. Conclusion. Using univariate and multivariate analysis, risk factors for developing pneumonia were disclosed. Some of these factors may be modified by simple medical procedures, thus the incidence and mortality rate of pneumonia in drug poisoning might be substantially reduced.

Superoxide dismutase moderates basal and induced bacterial adherence and interleukin-8 expression in airway epithelial cells

Bacterial infection of the tracheobronchial tree is a frequent, serious complication in patients receiving treatment with oxygen and mechanical ventilation, resulting in increased morbidity and mortality. Using human airway epithelial cell culture models, we examined the effect of hyperoxia on bacterial adherence and the expression of interleukin-8 (IL-8), an important mediator involved in the inflammatory process. A 24-h exposure to 95% O2increased Pseudomonas aeruginosa (PA) adherence 57% in A549 cells ( P < 0.01) and 115% in 16HBE cells ( P < 0.01) but had little effect on Staphylococcus aureus (SA) adherence. Exposure to hyperoxia, followed by a 1-h incubation with SA, further enhanced PA adherence ( P < 0.01), suggesting that hyperoxia and SA colonization may enhance the susceptibility of lung epithelial cells to gram-negative infections. IL-8 expression was also increased in cells exposed to both hyperoxia and PA. Stable or transient overexpression of manganese superoxide dismutase reduced both basal and stimulated levels of PA adherence and IL-8 levels in response to exposure to either hyperoxia or PA. These data indicate that hyperoxia increases susceptibility to infection and that the pathways are mediated by reactive oxygen species. Therapeutic intervention strategies designed to prevent accumulation of intracellular reactive oxygen species may reduce opportunistic pulmonary infections.

The role of oral microbial colonization in ventilator-associated pneumonia

The present article reviews the association between microbial colonization of the oral cavity and the lungs in critically ill patients that develop ventilator-associated pneumonia (VAP) in the intensive care unit (ICU) setting. The risk factors and microorganisms associated with VAP are presented. The role of oral colonization of VAP-associated pathogens (VAP-AP) in the development of VAP is examined. We explore the potential factors involved in oral colonization of VAP-AP, which are atypical bacteria for the oral cavity. Strategies for the prevention or moderation of oral colonization of VAP-AP have had limited success. We need a deeper understanding of the pathophysiology of VAP in order to reduce the morbidity, mortality, and cost from this common complication in ICU medicine and surgery.

Prevention of hospital-associated pneumonia and ventilator-associated pneumonia

OBJECTIVE

To synthesize the available clinical data for the prevention of hospital-associated pneumonia (HAP) and ventilator-associated pneumonia (VAP) into a practical guideline for clinicians.

DATA SOURCE

A Medline database and references from identified articles were used to perform a literature search relating to the prevention of HAP/VAP.

CONCLUSIONS

There is convincing evidence to suggest that specific interventions can be employed to prevent HAP/VAP. The evidence-based interventions focus on the prevention of aerodigestive tract colonization (avoidance of unnecessary antibiotics and stress ulcer prophylaxis, use of sucralfate for stress ulcer prophylaxis, chlorhexidine oral rinse, selective digestive decontamination, short-course parenteral prophylactic antibiotics in high-risk patients) and the prevention of aspiration of contaminated secretions (preferred oral intubation, appropriate intensive care unit staffing, avoidance of tracheal intubation with the use of mask ventilation, application of weaning protocols and optimal use of sedation to shorten the duration of mechanical ventilation, semirecumbent positioning, minimization of gastric distension, subglottic suctioning, avoidance of ventilator circuit changes/manipulation, routine drainage of ventilator circuit condensate). Clinicians caring for patients at risk for HAP/VAP should promote the development and application of local programs encompassing these interventions based on local resource availability, occurrence rates of HAP/VAP, and the prevalence of infection due to antibiotic-resistant bacteria (Pseudomonas aeruginosa, Acinetobacter species, and methicillin-resistant Staphylococcus aureus).

An educational intervention to reduce ventilator-associated pneumonia in an integrated health system: a comparison of effects

STUDY OBJECTIVES

To determine whether an educational initiative could decrease rates of ventilator-associated pneumonia in a regional health-care system.

SETTING

Two teaching hospitals (one adult, one pediatric) and two community hospitals in an integrated health system.

DESIGN

Preintervention and postintervention observational study.

PATIENTS

Patients admitted to the four participating hospitals between January 1, 1999, and June 30, 2002, who acquired ventilator-associated pneumonia.

INTERVENTION

An educational program for respiratory care practitioners and ICU nurses emphasizing correct practices for the prevention of ventilator-associated pneumonia. The program included a self-study module on risk factors for, and strategies to prevent, ventilator-associated pneumonia and education-based in-services. Fact sheets and posters reinforcing the information were posted throughout the ICU and respiratory care departments.

MEASUREMENTS AND RESULTS

Completion rates for the module were calculated by job title at each hospital. Rates of ventilator-associated pneumonia per 1,000 ventilator days were calculated for all hospitals combined and for each hospital separately. Overall 635 of 792 ICU nurses (80.1%) and 215 of 239 respiratory therapists (89.9%) completed the study module. There were 874 episodes of ventilator-associated pneumonia at the four hospitals during the 3.5-year study period out of 129,527 ventilator days. Ventilator-associated pneumonia rates for all four hospitals combined dropped by 46%, from 8.75/1,000 ventilator days in the year prior to the intervention to 4.74/1,000 ventilator days in the 18 months following the intervention (p < 0.001). Statistically significant decreased rates were observed at the pediatric hospital and at two of the three adult hospitals. No change in rates was seen at the community hospital with the lowest rate of study module completion among respiratory therapists (56%).

CONCLUSIONS

Educational interventions can be associated with decreased rates of ventilator-associated pneumonia in the ICU setting. The involvement of respiratory therapy staff in addition to ICU nurses is important for the success of educational programs aimed at the prevention of ventilator-associated pneumonia.

Antiseptic impregnated endotracheal tubes for the prevention of bacterial colonization

The effect of endotracheal tubes (ETTs) impregnated with chlorhexidine (CHX) and silver carbonate (antiseptic ETTs) against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacter aerogenes [organisms associated with ventilator-associated pneumonia (VAP)], was evaluated in a laboratory airway model. Antiseptic ETTs and control ETTs (unimpregnated) were inserted in culture tubes half-filled with agar media (airway model) previously contaminated at the surface with 10(8) cfu/mL of the selected test organism. After five days of incubation, bacterial colony counts on all ETT segments were determined. Swabs of proximal and distal ends of the agar tract in antiseptic and control models were subcultured. The initial and residual CHX levels, (five days post-implantation in the model) were determined. Cultures of antiseptic ETTs revealed colonization by the tested pathogens ranging from 1-100 cfu/tube, compared with approximately 10(6) cfu/tube for the control ETTs (P < 0.001). Subcultures from proximal and distal ends of the agar tract showed minimal or no growth in the antiseptic ETTs compared with the control ETTs (P < 0.001). The amount of CHX retained in the antiseptic ETTs after five days of implantation was an average of 45% of the initial level. Antiseptic ETTs prevented bacterial colonization in the airway model and also retained significant amounts of the antiseptic. These results indicate that the effectiveness of antiseptic-impregnated ETTs in preventing the growth of bacterial pathogens associated with VAP may vary with different organisms.

Costs and risk factors for ventilator-associated pneumonia in a Turkish university hospital's intensive care unit: a case-control study

Background

Ventilator-associated pneumonia (VAP) which is an important part of all nosocomial infections in intensive care unit (ICU) is a serious illness with substantial morbidity and mortality, and increases costs of hospital care. We aimed to evaluate costs and risk factors for VAP in adult ICU.

Methods

This is a-three year retrospective case-control study. The data were collected between 01 January 2000 and 31 December 2002. During the study period, 132 patients were diagnosed as nosocomial pneumonia of 731 adult medical-surgical ICU patients. Of these only 37 VAP patients were assessed, and multiple nosocomially infected patients were excluded from the study. Sixty non-infected ICU patients were chosen as control patients.

Results

Median length of stay in ICU in patients with VAP and without were 8.0 (IQR: 6.5) and 2.5 (IQR: 2.0) days respectively (P < 0.0001). Respiratory failure (OR, 11.8; 95%, CI, 2.2–62.5; P < 0.004), coma in admission (Glasgow coma scale < 9) (OR, 17.2; 95% CI, 2.7–107.7; P < 0.002), depressed consciousness (OR, 8.8; 95% CI, 2.9–62.5; P < 0.02), enteral feeding (OR, 5.3; 95% CI, 1.0–27.3; P = 0.044) and length of stay (OR, 1.3; 95% CI, 1.0–1.7; P < 0.04) were found as important risk factors. Most commonly isolated microorganism was methicillin resistant Staphylococcus aureus (30.4%). Mortality rates were higher in patients with VAP (70.3%) than the control patients (35.5%) (P < 0.003). Mean cost of patients with and without VAP were 2832.2+/-1329.0 and 868.5+/-428.0 US Dollars respectively (P < 0.0001).

Conclusion

Respiratory failure, coma, depressed consciousness, enteral feeding and length of stay are independent risk factors for developing VAP. The cost of VAP is approximately five-fold higher than non-infected patients.

Red blood cell transfusion and ventilator-associated pneumonia: A potential link?

OBJECTIVE

To determine the relationship between packed red blood cell transfusion practice and the development of ventilator-associated pneumonia (VAP).

DESIGN

Secondary analysis of a multicentered, prospective observational study of transfusion practice in intensive care units in the United States.

SETTING

A total of 284 intensive care units in the United States were studied from August 2000 to April 2001.

PATIENTS

Patients without pneumonia at intensive care unit admission and who then required at least 48 hrs of mechanical ventilation were considered at risk for VAP.

MEASUREMENTS AND MAIN RESULTS

VAP was diagnosed based on prospectively defined clinical criteria and represented the primary study end point. Late-onset VAP (VAP arising after > or =5 days of mechanical ventilation) represented a secondary end point. Transfusions given during the intensive care unit stay and before the onset of VAP were tracked prospectively. Of 4,892 subjects in the original cohort, 1,518 received mechanical ventilation of > or =48 hrs and did not have preexisting pneumonia. VAP was diagnosed in 311 (20.5%) patients. Multivariate analysis revealed that transfusion independently increased the risk for VAP (odds ratio, 1.89; 95% confidence interval [CI], 1.33-2.68). Other factors increasing the risk for VAP included male sex (odds ratio, 1.54; 95% CI, 1.15-2.07), admission after trauma (odds ratio, 1.68; 95% CI, 1.15-2.47), use of continuous sedation (odds ratio, 1.43; 95% CI, 1.07-1.92), and type of nutritional support (e.g., early enteral nutrition: odds ratio, 2.65; 95% CI, 1.93-3.63; total parenteral nutrition: odds ratio, 3.27; 95% CI, 2.24-4.75). The effect of transfusion on late-onset VAP was more pronounced (odds ratio, 2.16; 95% CI, 1.27-3.66) and demonstrated a positive dose-response relationship (p =.0223 for trend test).

CONCLUSIONS

Transfusion of packed red blood cells increases the risk of developing VAP. Avoiding the unnecessary use of packed red blood cell transfusions may decrease the occurrence of VAP.

Endotracheal tube intraluminal volume loss among mechanically ventilated patients*

OBJECTIVE

To measure endotracheal tube intraluminal volume loss among mechanically ventilated patients.

DESIGN

Prospective observational study.

SETTING

Medical intensive care unit (19 beds) of an urban university-affiliated teaching hospital.

PATIENTS

A total of 101 patients with acute respiratory failure requiring >24 hrs of mechanical ventilation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Acoustic reflectometry was employed to measure the intraluminal volume of 13-cm endotracheal tube segments. The endotracheal tube segment volumes were statistically smaller among endotracheal tubes used in patients compared with unused endotracheal tubes (5.4 +/- 0.7 vs. 6.0 +/- 0.6 mL, p <.001). The average percentage difference in endotracheal tube segment volumes, between the unused endotracheal tubes and the endotracheal tubes used in patients, was 9.8% (range, 0-45.5%). The percentage difference in the endotracheal tube segment volumes increased significantly with increasing duration of tracheal intubation (r2 =.766, p <.001). The minimum diameter of the endotracheal tube segments was also statistically smaller among endotracheal tubes used in patients compared with the unused endotracheal tubes (7.5 +/- 0.4 vs. 6.7 +/- 1.2 mm, p <.001).

CONCLUSIONS

Endotracheal tube intraluminal volume loss is common among patients with acute respiratory failure requiring mechanical ventilation and increases with prolonged tracheal intubation.

Ventilator-associated pneumonia: caveats for benchmarking

OBJECTIVE

To determine the influence of using different denominators on risk estimates of ventilator-associated pneumonia (VAP).

DESIGN AND SETTING

Prospective cohort study in the medical ICU of a large teaching hospital.

PATIENTS

All consecutive patients admitted for more than 48 h between October 1995 and November 1997.

MEASUREMENTS AND RESULTS

We recorded all ICU-acquired infections using modified CDC criteria. VAP rates were reported per 1,000 patient-days, patient-days at risk, ventilator-days, and ventilator-days at risk. Of the 1,068 patients admitted, VAP developed in 106 (23.5%) of those mechanically ventilated. The incidence of the first episode of VAP was 22.8 per 1,000 patient-days (95% CI 18.7-27.6), 29.6 per 1,000 patient-days at risk (24.2-35.8), 35.7 per 1,000 ventilator-days (29.2-43.2), and 44.0 per 1,000 ventilator-days at risk (36.0-53.2). When considering all episodes of VAP (n=127), infection rates were 27.3 episodes per 1,000 ICU patient-days (95% CI 22.6-32.1) and 42.8 episodes per 1,000 ventilator-days (35.3-50.2).

CONCLUSIONS

The method of reporting VAP rates has a significant impact on risk estimates. Accordingly, clinicians and hospital management in charge of patient-care policies should be aware of how to read and compare nosocomial infection rates.

Selective digestive decontamination should not be routinely employed

There is a general consensus that antimicrobial resistance in the hospital setting has emerged as an important variable influencing patient outcome and resource utilization. Hospitals worldwide are faced with increasingly rapid emergence and spread of antibiotic-resistant bacteria. Both antibiotic-resistant Gram-negative bacilli and Gram-positive bacteria are reported as important causes of hospital-acquired infections. Few antimicrobial agents are available for effective treatment. Selective digestive decontamination (SDD) is a technique aimed at selectively eliminating aerobic Gram-negative bacilli and yeast from the mouth and stomach to reduce the occurrence of hospital-acquired infections, including ventilator-associated pneumonia. Unfortunately, the application of SDD has been associated with emergence of antibiotic-resistant bacterial strains, limiting its overall utility.

Effect of an education program aimed at reducing the occurrence of ventilator-associated pneumonia

OBJECTIVE

The purpose of the study was to determine whether an education initiative could decrease the hospital rate of ventilator-associated pneumonia.

DESIGN

Pre- and postintervention observational study.

SETTING

Five intensive care units in Barnes-Jewish Hospital, an urban teaching hospital.

PATIENTS

Patients requiring mechanical ventilation who developed ventilator-associated pneumonia between October 1, 1999, and September 30, 2001.

INTERVENTIONS

An education program directed toward respiratory care practitioners and intensive care unit nurses was developed by a multidisciplinary task force to highlight correct practices for the prevention of ventilator-associated pneumonia. The program consisted of a ten-page self-study module on risk factors and practice modifications involved in ventilator-associated pneumonia, inservices at staff meetings, and formal didactic lectures. Each participant was required to take a preintervention test before the study module and identical postintervention tests following completion of the study module. Fact sheets and posters reinforcing the information in the study module were also posted throughout the intensive care units and the Department of Respiratory Care Services.

MEASUREMENTS AND MAIN RESULTS

One hundred ninety-one episodes of ventilator-associated pneumonia occurred in 15,094 ventilator days (12.6 per 1,000 ventilator days) in the 12 months before the intervention. Following implementation of the education module, the rate of ventilator-associated pneumonia decreased to 81 episodes in 14,171 ventilator days (5.7 per 1,000 ventilator days), a decrease of 57.6% (p <.001). The estimated cost savings secondary to the decreased rate of ventilator-associated pneumonia for the 12 months following the intervention were between $425,606 and $4.05 million.

CONCLUSIONS

A focused education intervention can dramatically decrease the incidence of ventilator-associated pneumonia. Education programs should be more widely employed for infection control in the intensive care unit setting and can lead to substantial decreases in cost and patient morbidity attributed to hospital-acquired infections.

Silver-coated endotracheal tubes associated with reduced bacterial burden in the lungs of mechanically ventilated dogs

STUDY OBJECTIVES

To evaluate the influence of silver-coated endotracheal tubes on the lung bacterial burden of mechanically ventilated dogs.

DESIGN

Randomized, double-blinded, controlled experiment.

SETTING

Animal research facility of a regional medical university.

PATIENTS OR PARTICIPANTS

Eleven healthy adult dogs.

INTERVENTIONS

The dogs were intubated either with cuffed, noncoated endotracheal tubes or with endotracheal tubes having a novel antimicrobial silver hydrogel coating and were challenged with buccal administration of Pseudomonas aeruginosa.

MEASUREMENTS AND RESULTS

The silver coating delayed the appearance of bacteria on the inner surface of the endotracheal tubes ([mean +/- SD] duration of mechanical ventilation before appearance of bacteria, 3.2 +/- 0.8 days; mean duration of mechanical ventilation, 1.8 +/- 0.4 days; p = 0.016). The mean total aerobic bacterial burden in the lung parenchyma was statistically lower among the dogs receiving the silver-coated endotracheal tubes compared to those not receiving them (4.8 +/- 0.8 vs 5.4 +/- 9 log cfu/g lung tissue, respectively; p = 0.010). Pronounced differences were seen in the gross and histologic assessments of inflammation in the lung. Using an increasing severity scale of 0 to 12 to assess four components of histology (ie, hyperemia, edema, cellular infiltration, and bacterial presence), dogs receiving noncoated endotracheal tubes had statistically greater histology scores compared to dogs receiving silver-coated endotracheal tubes (7.1 plus minus 1.6 vs 2.8 plus minus 1.2, respectively; p < 0.001).

CONCLUSION

These results suggest that the silver coating of endotracheal tubes may delay the onset of and decrease the severity of lung colonization by aerobic bacteria. Based on these results, clinical studies are planned to determine the safety and clinical efficacy of silver-coated endotracheal tubes in patients requiring mechanical ventilation in the ICU setting.

Postoperative nosocomial pneumonia: nurse-sensitive interventions

Nosocomial pneumonia (NP) is well documented as the second most common nosocomial infection. It is now more common in surgical patients than surgical-site or wound infection. Healthcare implications of NP include not only increased patient morbidity and mortality, but also increased use of healthcare resources. The advanced practice nurse plays an integral role in the prevention and minimization of NP across healthcare settings. This article focuses on postoperative NP after abdominal, cardiac, or thoracic surgery in the non-mechanically ventilated patient and discusses the diagnostic assessment, risk factors, and potential nurse-sensitive interventions to prevent or minimize this complication. Ideas for potential nursing research related to these risk factors are described.

Inadequate antimicrobial treatment: an important determinant of outcome for hospitalized patients

Inadequate antimicrobial treatment, generally defined as microbiological documentation of an infection that is not being effectively treated, is an important factor in the emergence of infections due to antibiotic-resistant bacteria. Factors that contribute to inadequate antimicrobial treatment of hospitalized patients include prior antibiotic exposure, use of broad-spectrum antibiotics, prolonged length of stay, prolonged mechanical ventilation, and presence of invasive devices. Strategies to minimize inadequate treatment include consulting an infectious disease specialist, using antibiotic practice guidelines, and identifying quicker methods of microbiological identification. In addition, clinicians should determine the prevailing pathogens that account for the community-acquired and nosocomial infections identified in their hospitals. Clinicians can improve antimicrobial treatment by using empirical combination antibiotic therapy based on individual patient characteristics and the predominant bacterial flora and their antibiotic susceptibility profiles. This broad-spectrum therapy can then be narrowed when initial culture results are received. Further study evaluating the use of antibiotic practice guidelines and strategies to reduce inadequate treatment is necessary to determine their impact on patient outcomes.