EPIDEMIOLOGY OF NOSOCOMIAL PNEUMONIA IN INTENSIVE CARE UNIT PATIENTS

Epidemiologic Study of Intensive Care Unit Admission in South Korea: A Nationwide Population-Based Cohort Study from 2010 to 2019

We aimed to investigate the trends of intensive care unit (ICU) admissions in South Korea from 2010 to 2019. We included all adult patients (≥20 years old) who were admitted to the ICU during hospitalization from 2010 to 2019 in South Korea. There were 3,517,423 ICU admissions of 2,461,848 adult patients. Of the ICU admission cases, 66.8% (2,347,976/3,517,423) were surgery-associated admissions, and the rate of in-hospital mortality after ICU admission was 12.0% (422,155 patients). The most common diagnoses were diseases of the circulatory system (36.8%) and pneumonia (4%). The 30-day, 90-day, and 1-year mortality rates were 16.0%, 23.6%, and 33.3% in 2010, and these values slightly decreased by 2019 to 14.7%, 22.1%, and 31.7%, respectively. The proportions of continuous renal replacement therapy (CRRT) use and extracorporeal membrane oxygenation (ECMO) support were 2.0% and 0.3% in 2010, and these values gradually increased by 2019 to 4.7% and 0.8%, respectively. Although the age and cost of hospitalization among critically ill patients who were admitted to the ICU increased from 2010 to 2019, the mortality rate decreased slightly. Moreover, the proportions of ECMO support and CRRT use had increased in our South Korean cohort.

Mutations in AR or SRD5A2 Genes: Clinical Findings, Endocrine Pitfalls, and Genetic Features of Children with 46,XY DSD

OBJECTIVE

Androgen insensivity syndrome (AIS) and 5α-reductase deficiency (5α-RD) present with indistinguishable phenotypes among the 46,XY disorders of sexual development (DSD) that usually necessitate molecular analyses for the definitive diagnosis in the prepubertal period. The aim was to evaluate the clinical, hormonal and genetic findings of 46,XY DSD patients who were diagnosed as AIS or 5α-RD.

METHODS

Patients diagnosed as AIS or 5α-RD according to clinical and hormonal evaluations were investigated. Sequence variants of steroid 5-α-reductase type 2 were analyzed in cases with testosterone/dihydrotestosterone (T/DHT) ratio of ≥20, whereas the androgen receptor (AR) gene was screened when the ratio was <20. Stepwise analysis of other associated genes were screened in cases with no causative variant found in initial analysis. For statistical comparisons, the group was divided into three main groups and subgroups according to their genetic diagnosis and T/DHT ratios.

RESULTS

A total of 128 DSD patients from 125 non-related families were enrolled. Birth weight SDS and gestational weeks were significantly higher in 5α-RD group than in AIS and undiagnosed groups. Completely female phenotype was higher in all subgroups of both AIS and 5α-RD patients than in the undiagnosed subgroups. In those patients with stimulated T/DHT <20 in the prepubertal period, stimulated T/DHT ratio was significantly lower in AIS than in the undiagnosed group, and higher in 5α-RD. Phenotype associated variants were detected in 24% (n=18 AIS, n=14 5α-RD) of the patients, revealing four novel AR variants (c.94G>T, p.Glu32*, c.330G>C, p.Leu110=; c.2084C>T, p.Pro695Leu, c.2585_2592delAGCTCCTG, p.(Lys862Argfs*16), of these c.330G>C with silent status remained undefined in terms of its causative effects.

CONCLUSION

T/DHT ratio is an important hormonal criterion, but in some cases, T/DHT ratio may lead to diagnostic confusion. Molecular diagnosis is important for the robust diagnosis of 46,XY DSD patients. Four novel AR variants were identified in our study.

Detection of respiratory viruses in adults with respiratory tract infection using a multiplex PCR assay at a tertiary center

Background

Respiratory viruses (RVs) are among the most common pathogens for both upper and lower respiratory tract infections (RTIs). However, the viral epidemiology of RV-associated RTIs in adults has long been under-recognized. Through a sensitive molecular assay, it would be possible to have a better understanding of the epidemiology of RV-associated RTIs.

Material and methods

Respiratory tract (RT) specimens from adults hospitalized due to RTIs were tested for RVs, using the multiplex PCR-based Luminex xTAG® Respiratory Viral Panel assay. A total of nineteen RVs, including influenza viruses and non-influenza respiratory viruses (NIRVs) were detected. Positive rates were compared using a chi-square test.

Results

A total of 2292 samples from adult patients hospitalized with RTIs were screened for RVs. The overall positive rate was 22%, with 17.8% samples positive for at least one NIRV. NIRVs had a higher positive rate in non-winter seasons. As many as 12.7% (46/363) of the samples collected through broncho-alveolar lavage and 20.5% (176/859) of the samples collected in ICUs were positive for RVs. Distribution of corona virus (CoV), human metapneumovirus (hMPV) and parainfluenza virus (PIV) demonstrated seasonal variation. Also, temperature was associated with the positive rates of specific viruses, including CoV, respiratory syncytial virus (RSV), hMPV and PIV.

Conclusion

Respiratory viruses, notably NIRVs, were frequently detected in adults hospitalized with RTIs. Several RVs were detected with distinctive seasonal variations. A substantial number of RVs were identified in lower RT specimens or from patients admitted to ICU, highlighting their important role in causing severe respiratory infection.

Hospital-acquired pneumonia among pediatric trauma patients treated at national trauma centers

BACKGROUND

Injury is the leading cause of hospitalization in children, and as many as 5% of hospitalized injured children require mechanical ventilation. Despite this, little is known about the complications associated with mechanical ventilation, including pneumonia.

METHODS

This is a retrospective analysis of trauma patients younger than 19 years from the National Trauma Data Bank from 2009 to 2011. Descriptive statistics were used to examine the patient population. Baseline characteristics were compared between subgroups using t tests and χ tests. Generalized linear models were used to identify risk factors for hospital-acquired pneumonia adjusting for clustering of patients by hospital.

RESULTS

A total of 252,187 patients were eligible for analysis, and 1,915 patients were diagnosed with pneumonia. Most patients were male (66.3%), were white (54.2%), had no comorbidities (88.9%), and were not considered severely injured (85.5% with an Injury Severity Score [ISS] < 16). The mean (SD) length of stay was 2.9 (5.2) days. Patients who developed pneumonia were older (16-18 years, 61.7% vs. 31.1%, p < 0.0001), had an increased length of stay (20.9 days vs. 2.8 days, p < 0.0001), more intensive care days (13.9 days vs. 0.7 days, p < 0.0001), and more ventilation days (9.5 days vs. 0.3 days, p < 0.0001) compared with those who did not develop pneumonia. The rate of pneumonia nearly doubled in patients spending 2 days on a ventilator (odds ratio [OR], 5.52; 95% confidence interval [CI], 3.45-8.84), doubled again for patients spending 3 days (OR, 10.59; 95% CI, 6.38-17.61), and doubled again for patients spending 5 days (OR, 23.72; 95% CI, 13.36-42.15) mechanically ventilated. The presence of two comorbid conditions was associated with twice the odds of developing pneumonia (OR, 2.10; 95% CI, 1.47-1.78).

CONCLUSION

Prolonged mechanical ventilation, increased injury severity, older age, and presence of multiple comorbid conditions all increase the risk of pneumonia in injured children. Preventive measures should be aggressively used in injured children at high risk for the development of pneumonia.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

Nosokomiale Pneumonie – Antibiotikatherapie und hygienische Interventionsstrategien

Die Pneumonie ist auch in unserer Zeit eine schwere Infektionskrankheit. Sie ist eine der häufigsten infektiösen Todesursachen der westlichen Industrieländer und steht an 3. Stelle unter den Infektionskrankheiten. Jede 4. ärztlich diagnostizierte Pneumonie ist nosokomial erworben. Nosokomiale Pneumonien führen neben einer verlängerten Morbidität und erhöhten Letalität zu einer Verlängerung der Krankenhausverweildauer und zu erheblichen Kosten.

Increased risk of pneumonia among ventilated patients with traumatic brain injury: every day counts!

BACKGROUND

Patients with traumatic brain injury (TBI) frequently require mechanical ventilation (MV). The objective of this study was to examine the association between time spent on MV and the development of pneumonia among patients with TBI.

MATERIALS AND METHODS

Patients older than 18 y with head abbreviated injury scale (AIS) scores coded 1-6 requiring MV in the National Trauma Data Bank 2007-2010 data set were included. The study was limited to hospitals reporting pneumonia cases. AIS scores were calculated using ICDMAP-90 software. Patients with injuries in any other region with AIS score >3, significant burns, or a hospital length of stay >30 d were excluded. A generalized linear model was used to determine the approximate relative risk of developing all-cause pneumonia (aspiration pneumonia, ventilator-associated pneumonia [VAP], and infectious pneumonia identified by the International Classification of Disease, Ninth Revision, diagnosis code) for each day of MV, controlling for age, gender, Glasgow coma scale motor score, comorbidity (Charlson comorbidity index) score, insurance status, and injury type and severity.

RESULTS

Among the 24,525 patients with TBI who required MV included in this study, 1593 (6.5%) developed all-cause pneumonia. After controlling for demographic and injury factors, each additional day on the ventilator was associated with a 7% increase in the risk of pneumonia (risk ratio 1.07, 95% confidence interval 1.07-1.08).

CONCLUSIONS

Patients who have sustained TBIs and require MV are at higher risk for VAP than individuals extubated earlier; therefore, shortening MV exposure will likely reduce the risk of VAP. As patients with TBI frequently require MV because of neurologic impairment, it is key to develop aggressive strategies to expedite ventilator independence.

A prospective, randomized trial of continuous lateral rotation ("kinetic therapy") in patients with cardiogenic shock

BACKGROUND

Continuous lateral rotation ["Kinetic therapy" (KT)] has been shown to reduce complications and to shorten hospital stay in trauma patients. Data in non-surgical patients is inconclusive. Retrospective data suggest a beneficial effect of KT in patients with cardiogenic shock (CS) requiring ventilator therapy. KT, however, has not been tested prospectively in those patients.

METHODS

A prospective, randomized, open-label trial was performed to compare KT using oscillating beds (TryaDyne Proventa, KCI) with standard care (SC). Patients with cardiogenic shock requiring ventilator therapy for more than 24 h were included. Primary endpoint was the occurrence of hospital-acquired pneumonia. Secondary endpoints were the occurrence of pressure ulcers during the hospital stay and 1-year all-cause mortality.

RESULTS

Forty-five patients were randomized to KT, and 44 to SC. All patients required at least one inotropic agent and one vasopressor for circulatory assistance. The groups were comparable in the etiology of heart disease, in the use of revascularization procedures, the use of balloon counterpulsation, and APACHE-II score (33 ± 5 vs. 33 ± 4) and SOFA score (11 ± 1 vs. 11 ± 1) at inclusion; however, more patients in SC were subject to resuscitation before inclusion. Hospital-acquired pneumonia occurred in 10 patients in KT and 28 patients in SC (p < 0.001); pressure ulcers were seen in 10 versus 2 patients (p < 0.001). Hospital mortality tended to be lower in KT, and 1-year all-cause mortality was 41 % in KT and 66 % in SC (p = 0.028).

CONCLUSION

The use of KT reduces rates of pneumonia and pressure ulcers as compared to SC. Moreover, in this study, patients with KT had a better outcome. The study suggests that KT should be used in patients with cardiogenic shock requiring ventilator therapy for a prolonged time.

Early, single chlorhexidine application reduces ventilator-associated pneumonia in trauma patients

BACKGROUND

Ventilator-associated pneumonia (VAP) is an important complication of mechanical ventilation and is particularly common in trauma, burn, and surgical patients. Interventions that kill bacteria in the oropharynx reduce the pool of viable organisms available for translocation to the lung and thereby lessen the likelihood of developing VAP. Repeated administration of chlorhexidine (CHX) to the mouth and oropharynx has been shown to reduce the incidence of VAP, but use of a single dose has not been studied. This randomized, controlled clinical trial tested an early (within 12 hours of intubation) application of CHX by swab versus control (no swab) on oral microbial flora and VAP.

METHODS

A total of 145 trauma patients requiring endotracheal intubation were randomly assigned to the intervention (5 mL CHX) or control group. VAP (Clinical Pulmonary Infection Score [CPIS] ≥ 6) was evaluated on study admission and at 48 and 72 hours after intubation.

RESULTS

A total of 145 patients were enrolled; 71 and 74 patients were randomized to intervention and control groups, respectively. Seventy percent of the patients were male, and 60% were white; their mean age was 42.4 years (±18.2). A significant treatment effect was found on CPIS both from admission to 48 hours (P = .020) and to 72 hours (P = .027). In those subjects without pneumonia at baseline (CPIS < 6), 55.6% of the control patients (10/18) had developed VAP by 48 or 72 hours versus only 33.3% of the intervention patients (7/21).

CONCLUSION

an early, single application of CHX to the oral cavity significantly reduces CPIS and thus VAP in trauma patients.

A comparison of linezolid with glycopeptides in severe MRSA pneumonia

Evaluation of: Luna CM, Bruno DA, García-Morato J et al. Effect of linezolid compared with glycopeptides in methicillin-resistant Staphylococcus aureus severe pneumonia in piglets. Chest 135(6), 1564-1571 (2009). Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major pathogen in nosocomial infections and accounts for a large proportion of nosocomial pneumonia. However, there are limited antibiotics available for the treatment of this serious and potentially lethal infection. Until recently, the only effective antibiotic was vancomycin, but the oxazolidinones, such as linezolid, have been shown to be a valuable addition to the arsenal of antimicrobial agents that can be used for MRSA pneumonia. Clinical trials have been conducted to compare vancomycin and linezolid head-to-head in pneumonia and, in post hoc subgroup analyses, showed that linezolid use was associated with improved survival. The ensuing debate over these results was dominated by two opinions; there were those who speculated on the mechanism by which linezolid achieved this benefit, namely attributing it to pharmacodynamics and pharmacokinetics, and others who criticized the methodology of the studies and questioned the validity of the results altogether. This study by Luna and colleagues was designed with several goals in mind. The first was to attempt to generate an animal model of MRSA pneumonia in piglets by duplicating techniques used in animal models of Gram-negative pneumonia. Then they studied the effect of three antibiotics (vancomycin, linezolid and teicoplanin) on outcomes in the same model, while simultaneously measuring antibiotic levels in the serum, bronchoalveolar lavage fluid and lung tissue, in an attempt to attribute differences in survival to pharmacological properties of the drugs used. Their results showed a survival benefit only for linezolid, despite the fact that all three antibiotics had levels above MIC in all the compartments sampled, leading them to speculate that linezolid may have improved outcomes by mechanisms not directly related to its antimicrobial actions.

Higiene bucal com clorexidina na prevenção de pneumonia associada à ventilação mecânica

A pneumonia associada à ventilação mecânica (PAVM) é uma infecção freqüente nas unidades de terapia intensiva (UTI), e anti-sépticos bucais são utilizados preventivamente. Revisamos metanálises e ensaios clínicos randomizados indexados no Medical Literature Analysis and Retrieval System e Cumulative Index to Nursing and Allied Health Literature sobre o uso tópico da clorexidina na prevenção da PAVM. Oito publicações foram avaliadas. Em sete (87,5%), a clorexidina diminuiu a colonização da orofaringe, e em quatro (50%) houve redução de PAVM. A clorexidina parece diminuir a colonização, podendo reduzir a incidência da PAVM.

Examining the association between chest tube-related factors and the risk of developing healthcare-associated infections in the ICU of a community hospital: a retrospective case-control study

OBJECTIVES

The study examined the association between chest tube-related factors and the risk for developing healthcare-associated infections (HAI).

RESEARCH METHODOLOGY

A case-control retrospective chart review was performed on 120 intensive care patients. Eligible patients were 18 years of age or older, had been in the intensive care unit (ICU) for 48 h or more, and had one or more chest tubes.

SETTING

A 20-bed medical-surgical intensive care unit (ICU) of a community hospital in south-western Ontario, Canada.

MAIN OUTCOME MEASURES

Documented diagnosis of hospital-acquired pneumonia or bloodstream infection.

RESULTS

The variable chest tube days was the only chest tube-related factor that was independently associated with HAI (OR = 5.78; p = 0.013). Mechanical ventilation (OR = 4.88; p = 0.002) and outcome length of stay (OR = 0.72; p < or = 0.001) were also independently associated with HAI.

CONCLUSIONS

The risk of infection among patients with chest tubes increases as the number of chest tube days increases. Infection is likely to happen early during admission, which necessitates stringent adherence to infection control strategies, especially during that time frame.

Efficacy and safety of doripenem versus piperacillin/tazobactam in nosocomial pneumonia: a randomized, open-label, multicenter study

OBJECTIVE

Doripenem is a new carbapenem that has broad-spectrum activity against bacterial pathogens commonly responsible for nosocomial pneumonia (NP). It has several advantages over currently available carbapenems and other classes of drugs used in this indication. This prospective, randomized, open-label, multicenter study was designed to establish whether doripenem was noninferior to piperacillin/tazobactam in NP.

METHODS

Adults (n=448) with signs and symptoms of NP, including non-ventilated patients and those ventilated for <5 days, were stratified by ventilation mode, illness severity (Acute Physiology and Chronic Health Evaluation II score), and geographic region and then randomly allocated to treatment with doripenem 500 mg every 8 h by a 1-h intravenous (IV) infusion or piperacillin/tazobactam 4.5 g every 6 h by 30-min IV infusion. After receiving IV study drug for at least 72 h, eligible patients could be switched to oral levofloxacin 750 mg once daily. Antibiotic therapy was continued for a total of 7-14 days. The primary endpoint was the clinical cure rate, assessed 7-14 days after treatment completion, in clinically evaluable patients and in the clinical modified intent-to-treat population (cMITT).

TRIAL REGISTRATION

ClinicalTrials.gov, NCT00211003.

RESULTS

Doripenem was noninferior to piperacillin/tazobactam. Clinical cure rates in clinically evaluable patients (n=253) were 81.3% in the doripenem arm and 79.8% in the piperacillin/tazobactam arm (between-treatment difference: 1.5%; 95% confidence interval [CI], -9.1 to 12.1%) and in the cMITT population 69.5% and 64.1%, respectively, (between-treatment difference: 5.4%; 95% CI, -4.1 to 14.8%). Baseline resistance of Klebsiella pneumoniae and Pseudomonas aeruginosa to piperacillin/tazobactam was 44% and 26.9%, respectively; a doripenem minimum inhibitory concentration (MIC) >8 mug/mL occurred in 0% and 7.7%, respectively. Favorable microbiological outcome rates against Gram-negative pathogens were numerically higher with doripenem than with piperacillin/tazobactam, but the difference was not statistically significant. Both study drugs were generally well tolerated, as only 16.1% and 17.6% of patients receiving doripenem and piperacillin/tazobactam, respectively, had a drug-related adverse event. Study limitations included the open-label design, the low rate of monotherapy (adjunctive use of aminoglycoside was required when P. aeruginosa was suspected), and the exclusion of the most critically ill and immunocompromized patients.

CONCLUSIONS

Doripenem was clinically and microbiologically effective in patents with NP, including those with early-onset ventilator-associated pneumonia, and was therapeutically noninferior to piperacillin/tazobactam.

Linezolid versus glycopeptide or beta-lactam for treatment of Gram-positive bacterial infections: meta-analysis of randomised controlled trials

Linezolid has been approved for the treatment of patients with infections caused by Gram-positive cocci that are resistant to traditionally used antibiotics, including glycopeptides. This oxazolidinone antibiotic has been reported to have excellent pharmacokinetics and effectiveness. We did a meta-analysis of randomised controlled trials (RCTs) to clarify whether linezolid is superior to glycopeptides or beta-lactams for the treatment of Gram-positive infections. 12 RCTs, involving 6093 patients, were included. Overall, with respect to treatment success, linezolid was more effective than glycopeptides or beta-lactams (odds ratio [OR] 1.41 [95% CI 1.11-1.81]). Mortality was similar between the groups (OR 0.97 [0.79-1.19]). Linezolid was more effective than comparators in patients with skin and soft-tissue infections (OR 1.67 [1.31-2.12]) and bacteraemia (OR 2.07 [1.13-3.78]). However, there was no difference in treatment success for patients with pneumonia (OR 1.03 [0.75-1.42]). Treatment with linezolid was not associated with more adverse effects in general (OR 1.40 [0.95-2.06]); however, thrombocytopenia was recorded more commonly in patients receiving linezolid (OR 11.72 [3.66-37.57]). Although linezolid is more effective than its comparators for the empirical treatment of selected patients, several points, such as the use of less potent antistaphylococcal beta-lactams, the same all-cause mortality, and the higher probability of thrombocytopenia, should be taken into account and may limit the use of linezolid to specific patient populations or infections that are difficult to treat with other antibiotics.

Probiotics for preventing and treating nosocomial infections: review of current evidence and recommendations

OBJECTIVE

To review the available clinical data supporting the use of probiotics in preventing and treating serious nosocomial infections.

DATA SOURCE

A Medline database from 1996 to July 2006 and references from identified articles were used to perform a literature search relating to the clinical applications of probiotics in preventing and treating Clostridium difficile-associated diarrhea (CDD) and prevention of hospital-associated pneumonia (HAP).

CONCLUSION

Nosocomial infections like HAP and CDD contribute significantly to health-care costs in the United States. These clinical problems are associated with prolonged hospital stays and increased mortality in critically ill patients. The emergence of multidrug-resistant pathogens in cases of HAP and the recent description of an epidemic, toxin gene-variant strain of C difficile, combined with the anticipated lack of new antimicrobial agents in the near future emphasize the need for new, innovative strategies to prevent and treat these diseases. Probiotics normally function as colonizers and contribute to the overall health of their hosts by multiple mechanisms including immune and antibacterial effects. There is no current clinical evidence to support the use of probiotics to restore the normal human flora in critically ill patients and reduce HAP rates. Probiotics can prevent episodes of antibiotic-associated diarrhea, but their utility in treating and preventing CDD requires demonstration of benefit in multicenter clinical trials, preferably sponsored by the National Institutes of Health.

A novel method of continuous measurement of head of bed elevation in ventilated patients

OBJECTIVE

We developed a novel pressure transducer-based method of continuous measurement of head of bed elevation. Following validation of the method we hypothesized that head of bed angles would be at or above 30 degrees among mechanically ventilated patients throughout the day due to a hospital-wide initiative on ventilator-associated pneumonia prevention and standardized electronic order entry system to keep head of bed at an angle of 30 degrees or greater.

DESIGN AND SETTING

Prospective observational study in university hospital intensive care units.

PATIENTS AND PARTICIPANTS

Twenty-nine consecutive mechanically ventilated patients with no contraindications for semirecumbency.

MEASUREMENTS AND RESULTS

We acquired 113 pairs of measurements on unused beds for validation of the method at angles between 3 degrees and 70 degrees. Correlation between transducer and protractor was fitted into a linear regression model (R2 = 0.98) with minimal variation of data along the line of equality. Bland-Altman analysis showed a mean difference of 1.6 degrees +/- 1.6 degrees. Ninety-six percent of differences were within 2 SD from the mean. This method was then used among 29 intubated patients to collect head of bed data over a 24-h period for 3 consecutive days. Contrary to our hypothesis, all patients had head of bed angles less than 30 degrees.

CONCLUSIONS

Our results suggest that this method could be used with high reliability and patients in our institution were not kept even at 30 degrees. The results are in accord with those of a recent study which found that continued maintenance of previously suggested head of bed angles was difficult to attain clinically. This may lead us to reevaluate methods studying the impact of head of bed elevation in VAP prevention.

Inadequate treatment of ventilator-associated pneumonia: risk factors and impact on outcomes

Initial antibiotic therapy is an important determinant of clinical outcomes in ventilator-associated pneumonia (VAP). Several studies have investigated this issue, with conflicting results. This study investigated risk factors of inadequate empirical antimicrobial therapy and its impact on outcomes for patients with a clinical diagnosis of VAP. The primary outcome was adequacy of antimicrobial therapy. Secondary outcomes were duration of mechanical ventilation, hospital and intensive care unit (ICU) lengths of stay, and mortality due to VAP. Mean age was 62.9+/-15.2 years, mean APACHE (Acute Physiological Assessment and Chronic Health Evaluation) II score was 20.1+/-8.1 and mean MODS (Multiple Organ Dysfunction Score) was 3.7+/-2.5. Sixty-nine (45.7%) of 151 patients with a clinical diagnosis of VAP received inadequate antimicrobial treatment for VAP initially. There were 100 (66.2%) episodes of VAP caused by multidrug-resistant pathogens, of which 56% were inadequately treated, whereas the rate of inadequate antimicrobial therapy for VAP caused by susceptible-drug pathogens was 25.5% (P<0.001). Multiple logistic regression analysis revealed that the risk of inadequate antimicrobial treatment was more than twice as great for patients with late-onset VAP [odds ratio (OR), 2.93; 95% confidence interval (CI), 1.30-6.64; P=0.01], and more than three times for patients with VAP caused by multidrug-resistant pathogens (OR, 3.07; 95% CI, 1.29-7.30; P=0.01) or with polymicrobial VAP (OR, 3.67; 95% CI, 1.21-11.12; P=0.02). Inadequate antimicrobial treatment was associated with higher mortality for patients with VAP. Two of three independent risk factors for treatment inadequacy were associated with the isolation and identification of micro-organisms.

Postoperative infections after major heart surgery and prevention of ventilator-associated pneumonia: a one-day European prevalence study (ESGNI-008)

Few data have been published on the prevalence of postoperative infection in patients undergoing major heart surgery (MHS). The degree of compliance with standard measures used to prevent them is unknown. This study assessed the prevalence of infections, particularly ventilator-associated pneumonia (VAP), in patients undergoing MHS in 42 institutions from 13 European countries. On the study day, there were 321 postoperative MHS patients, of whom 164 (51%) were mechanically ventilated. The overall prevalence of infection was 26.8%. Lower respiratory tract infections represented 57% of all the infections present on the study day. Other infections included intravenous-catheter-related bloodstream infections (2.8%), surgical site infections (2.2%), urinary tract infections (0.9%) and postoperative mediastinitis (0.9%). Of the mechanically ventilated patients, 55 (33.5%) were not being nursed in a semi-recumbent position, 36 (22%) had heat-moisture exchangers with no antibacterial filters, and intracuff pressure was not monitored in 78 patients (47.6%). Only 13 patients (8%) were given continuous subglottic suctioning, 64 patients (39%) did not receive postural oscillation, and gastric overdistension was not actively prevented in 23 patients (14%). In conclusion, these data from intensive care units across Europe provide information on postoperative infections in an important subset of the patient population, and stress the need for active interventions to prevent VAP in patients undergoing MHS.

Oral health measurement in nursing research: state of the science

Oral health can impact general health and systemic disease. Changes in dental plaque, oral microbial flora, and local oral immunity may be important in the development or exacerbation of disease in critically ill patients, trauma patients, adults with chronic obstructive pulmonary disease, and frail elderly. Inasmuch as oral health potentially can be influenced by nursing interventions, nursing research in this area can contribute greatly to improved patient outcomes in these diverse populations. The authors' research teams have conducted several federally funded projects focused on oral health and have developed synergy in research methods. A unifying theme for these research projects is the measurement of oral health. Standardized measures of components of oral health are available and applicable across populations, and their uses and relationship to nursing research and patient outcomes will be discussed.

Optimizing antibiotic treatment for ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) is the most common infectious complication in patients receiving mechanical ventilation and accounts for exorbitant use of resources in the intensive care unit. Antimicrobial management of VAP incorporates an initial broad-spectrum, empiric regimen to ensure appropriate coverage with deescalation of therapy after 48-72 hours based on culture results and sensitivities. When VAP clinically responds to treatment, antimicrobials should be discontinued after 7-8 days to reduce overall antibiotic consumption and the selection pressure on flora observed in the intensive care unit and thus minimize the development and spread of antimicrobial resistance.

Oral care reduces incidence of ventilator-associated pneumonia in ICU populations

OBJECTIVE

To examine whether oral care contributes to preventing ventilator-associated pneumonia (VAP) in ICU patients.

DESIGN

Nonrandomized trial with historical controls.

SETTING

A medical-surgical ICU in a university hospital.

PATIENTS

1,666 mechanically ventilated patients admitted to the ICU.

INTERVENTION

Oral care was provided to 1,252 patients who were admitted to the ICU during period between January 1997 and December 2002 (oral care group), while 414 patients who were admitted to the ICU during period between January 1995 and December 1996 and who did not receive oral care served as historical controls (non-oral care group).

MEASUREMENTS AND RESULTS

Incidence of VAP(episodes of pneumonia per 1000 ventilator days) in the oral care group was significantly lower than that in the non-oral care group (3.9 vs 10.4). The relative risk of VAP in the oral care group compared to that in the non-oral care group was 0.37, with an attributable risk of -3.96%. Furthermore, length of stay in ICU before onset of VAP was greater in the oral care than in the non-oral care group (8.5+/-4.6 vs 6.3+/-7.5 days). However, no significant difference was observed in either duration of mechanical ventilation or length of stay between the groups (5.9+/-10.8 vs 6.0+/-8.8 days and 7.5+/-11.5 vs 7.2+/-9.5 days, respectively). Pseudomonoas aeruginosa was the most frequently detected bacteria in both groups. Number of potentially pathogenic bacteria in oral cavity was significantly reduced by single oral care procedure.

CONCLUSION

Oral care decreased the incidence of VAP in ICU patients.

DESCRIPTOR

Pulmonary nosocomial infection.

Health-Care–Associated Infections and Prevention

Health-care-associated infections (HAIs) are an important cause of perioperative morbidity and mortality. Currently, one out of every 10 surgical patients develops an HAI. Causes of HAIs vary, but include the transient immunodeficiency associated with surgery,immobility, and the presence of indwelling devices. With rates of antimicrobial resistance increasing, prevention remains the best solution. The investigators review the most frequently encountered health-care-associated infections with an emphasis on preventative strategies. The article addresses issues related to the diagnosis,treatment, and prevention of health-care-related pneumonia,health-care-associated urinary tract infections, and intravascular-catheter-related infections. The article also discusses the utility of hand hygiene policies.

Antibiotic Utilization and Outcomes for Patients With Clinically Suspected Ventilator-Associated Pneumonia and Negative Quantitative BAL Culture Results

OBJECTIVE

To evaluate antibiotic utilization and clinical outcomes among patients with clinically suspected ventilator-associated pneumonia (VAP) and culture-negative BAL (CNBAL).

DESIGN

Prospective observational cohort study.

SETTING

A medical ICU from a university-affiliated urban teaching hospital employing a previously described antibiotic discontinuation guideline for the management of VAP.

PATIENTS

One hundred one patients with a clinical suspicion of VAP and CNBAL were evaluated between July 2002 and December 2004.

INTERVENTIONS

Prospective patient follow-up and data collection. Antibiotic discontinuation was determined by the clinical guideline and not the results of BAL cultures.

RESULTS

The average age of the patients was 60.4 +/- 17.9 years and the mean APACHE II score was 23.2 +/- 8.7 (+/- SD). The mean duration of mechanical ventilation prior to clinically suspected VAP was 2.9 +/- 1.9 days. Nineteen patients (18.8%) received antibiotics for other indications prior to BAL. Empiric antibiotic therapy for VAP was begun in 65 patients (64.4%) following BAL. The duration of empiric antibiotic treatment following BAL was 2.1 +/- 0.8 days. None of these patients received antibiotics for > 3 days (median, 2 days; range, 1 to 3 days). Six patients (5.9%) were treated with antibiotics for a secondary episode of VAP or hospital-acquired pneumonia developing at least 72 h after the CNBAL was performed and discontinuation of the empiric antibiotic therapy prescribed for the initially suspected episode of VAP. Overall, 35 patients (34.7%) died during hospitalization. Two deaths occurred in patients with a secondary episode of VAP following CNBAL and discontinuation of empiric antimicrobial therapy. Neither of these two deaths was attributed to VAP.

CONCLUSIONS

Although the decision to discontinue antibiotic treatment was based on clinical criteria and not BAL culture results, this study suggests that patients with a clinical suspicion of VAP and CNBAL can have empiric antimicrobial therapy safely discontinued within 72 h or in some cases withheld altogether. Prospective studies are needed to determine the safety of employing CNBAL as the primary criterion for the discontinuation of empirically begun antibiotic treatment for VAP.

Successful Lung Transplantation From a Donor With a Saddle Pulmonary Embolus

Pulmonary embolus has received scant attention as a contraindication to lung donation. Reported is a case of a saddle pulmonary embolus successfully treated with thrombolytics in a donor whose lung was ultimately successfully transplanted. Discussed are the theoretical likelihood of thromboembolus in potential lung donors and the possible implications of pulmonary embolism on donor selection and lung physiology around the time of transplantation.

Ventilator-associated pneumonia: Increased bacterial counts in bronchoalveolar lavage by using urea as an endogenous marker of dilution

OBJECTIVE

Invasive diagnostic procedures such as bronchoalveolar lavage (BAL) with quantitative microbiological cultures are currently recommended for the diagnosis of nosocomial pneumonia. Commonly, in clinical practice, a threshold of > or =10 colony forming units/mL is used for therapeutic decisions. The use of these measurements in daily practice assumes that their repeatability is acceptable. However, many variations among the positive results have been noted. One of the most important is dilution of BAL, which may influence the quantitative results by minimizing bacterial counts. Knowledge of the extent of dilution may increase dramatically the value of quantitative cultures. The aim of this study was to determine to what extent specimens are diluted in BAL by measuring urea in BAL and blood. Furthermore, the impact of a potential dilution effect on the diagnosis of ventilator-associated pneumonia was studied.

PATIENTS AND SETTING

A total of 47 patients with ventilator-associated pneumonia in two medical intensive care units at the Vienna General Hospital, a university-affiliated facility.

DESIGN

Prospective study performed between January 2001 and July 2002.

METHODS

BAL fluid was divided immediately into two samples: one for direct microscopic examination of cytocentrifuge preparations for Gram staining to determine percentages of cells containing intracellular bacteria and one for quantitative cultures according to the Cumitech 7A guidelines. Epithelial lining fluid volume was calculated using urea as a marker of dilution and correlated with colony forming units per milliliter.

RESULTS

Nineteen out of 47 patients (40%) revealed significant bacterial growth (> or =10 colony forming units/mL). Eight additional patients (17%) would have reached the cutoff level after correction of the dilution effect, which varied between 1.8- and 130-fold.

CONCLUSIONS

Data suggest a great variation of dilution during BAL procedures, which influences quantitative results. Using urea to determine the dilution quotient could increase the value of bacterial thresholds in the diagnosis and therapeutic decision of ventilator-associated pneumonia.

High prevalence of respiratory viral infections in patients hospitalized in an intensive care unit for acute respiratory infections as detected by nucleic acid-based assays

Forty-seven bronchoalveolar lavages (BAL) were obtained from 41 patients with acute pneumonia attending an intensive care unit. By molecular diagnosis, 30% of total BAL and 63% of bacteria-negative BAL were positive for respiratory viruses. Molecular detection allows for high-rate detection of respiratory viral infections in adult patients suffering from severe pneumonia.

Gram-Negative Bacterial Resistance: Evolving Patterns and Treatment Paradigms

Successful treatment of patients with nosocomial pneumonia depends primarily on providing adequate initial antibiotic treatment in a timely manner, because an inappropriate course is closely associated with increased mortality. Gram-negative bacteria are commonly responsible for nosocomial pneumonia, and the increasing prevalence of drug resistance among these bacteria complicates decision making with regard to treatment with antibiotics. Infections due to Pseudomonas aeruginosa are particularly problematic because of their intrinsic resistance to multiple classes of antibiotics and their ability to acquire adaptive resistance during a therapeutic course. Numerous strategies, including the use of combination therapy followed by de-escalation of antibiotics, have shown promise in the treatment of these serious infections. However, future success in treating nosocomial infections depends on the appropriate and responsible use of antibiotics in the intensive care unit, to ensure that the antibiotics available today maintain their effectiveness in the future.

Pneumonia associada à ventilação mecânica: impacto da multirresistência bacteriana na morbidade e mortalidade

INTRODUÇÃO: A pneumonia associada à ventilação mecânica é a infecção hospitalar mais comum nas unidades de terapia intensiva. OBJETIVO: Determinar o impacto da multirresistência dos microorganismos na morbidade e mortalidade dos pacientes com pneumonia associada à ventilação mecânica. MÉTODO: Estudo de coorte retrospectivo. Em 40 meses consecutivos, 91 pacientes sob ventilação mecânica tiveram o diagnóstico de pneumonia. Os casos foram divididos entre causados por microorganismo multirresistente e causados por microorganismo sensível à antibioticoterapia. RESULTADOS: Pneumonia foi causada por microorganismo multirresistente em 75 casos (82,4%) e por microorganismo sensível 16 (17,6%) deles. As características clínicas e epidemiológicas não foram estatisticamente diferentes entre os grupos. O Staphylococcus aureus foi responsável por 27,5% dos episódios de pneumonia associada à ventilação mecânica e a Pseudomonas aeruginosa por 17,6%. A doença foi de início recente em 33 pacientes (36,3%) e de início tardio em 58 deles (63,7%). Os tempos de ventilação mecânica, de internação em unidade de terapia intensiva e de internação hospitalar total não diferiram. O tratamento empírico foi considerado inadequado em 42 pacientes com pneumonia por microorganismo multirresistente (56%) e em 4 com pneumonia por microorganismo sensível (25%) (p = 0,02). Óbito ocorreu em 46 pacientes com a pneumonia por microorganismo multirresistente (61,3%), e em 4 daqueles com pneumonia por microorganismo sensível (25%) (p = 0,008). CONCLUSÃO: A multirresistência bacteriana não determinou nenhum impacto na morbidade, mas esteve associada à maior mortalidade.

Preventing ventilator-associated pneumonia: evidence-based care

Ventilator-associated pneumonia is a common complication of mechanical ventilation with significant morbidity and mortality. This article summarizes the data related to specific risk factors associated with ventilator associated pneumonia (patient position, oral health, airway management, and gastrointestinal factors) and provides recommendations for practice based on the present evidence.

A randomized controlled trial of an antibiotic discontinuation policy for clinically suspected ventilator-associated pneumonia

OBJECTIVE

To evaluate an antibiotic discontinuation policy for clinically suspected ventilator-associated pneumonia (VAP).

DESIGN

Prospective, randomized, controlled clinical trial.

SETTING

A medical ICU from a university-affiliated urban teaching hospital.

PATIENTS

Between April 2002 and July 2003, 290 patients completed the clinical trial.

INTERVENTIONS

Patients were assigned to have the duration of antibiotic treatment for VAP determined by an antibiotic discontinuation policy (discontinuation group) or their treating physician teams (conventional group).

RESULTS

Severity of illness using APACHE (acute physiology and chronic health evaluation) II score (22.8 +/- 9.0 vs 23.2 +/- 9.4, p = 0.683) [mean +/- SD] and the clinical pulmonary infection score (7.1 +/- 0.9 vs 7.2 +/- 0.9, p = 0.222) were similar for both patient groups. The duration of antibiotic treatment for VAP was statistically shorter among patients in the discontinuation group compared to patients in the conventional antibiotic management group (6.0 +/- 4.9 days vs 8.0 +/- 5.6 days, p = 0.001). The occurrence of a secondary episode of VAP was not statistically different between these two groups (17.3% vs 19.3%, p = 0.667). Hospital mortality (32.0% vs 37.1%, p = 0.357) and ICU length of stay (6.8 +/- 6.1 days vs 7.0 +/- 7.3 days, p = 0.798) were also statistically similar.

CONCLUSIONS

The application of an antibiotic discontinuation policy for clinically suspected VAP was associated with a decrease in the overall duration of antibiotic treatment. These findings suggest that shorter courses of empiric antibiotic therapy for patients treated for clinically suspected VAP can be safely achieved.

Duration of action of a single, early oral application of chlorhexidine on oral microbial flora in mechanically ventilated patients: a pilot study

OBJECTIVE

The purpose of this study was to describe the effect of an early post-intubation oral application of chlorhexidine gluconate on oral microbial flora and ventilator-associated pneumonia.

METHODS

Thirty-four intubated patients were randomly assigned to chlorhexidine gluconate by spray or swab or to control group. Oral cultures were done at study admission, 12, 24, 48, and 72 hours, whereas the Clinical Pulmonary Infection Score (CPIS) was documented at study admission, 48, and 72 hours.

RESULTS

Reductions in oral culture scores (less growth) were only found in the treatment groups (swab and spray); no reduction was found in the control group. There was a trend for fewer positive cultures in the combined treatment groups. The mean CPIS for the control group increased to a level indicating pneumonia (4.7 to 6.6), whereas the CPIS for the treatment group increased only slightly (5.17 to 5.57).

CONCLUSIONS

Trends in the data suggest that use of chlorhexidine gluconate in the early post-intubation period may mitigate or delay the development of ventilator-associated pneumonia.

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).

Ventilator-associated pneumonia in a multi-hospital system: differences in microbiology by location

OBJECTIVE

To determine whether there were differences in the microbiologic etiologies of ventilator-associated pneumonia in different clinical settings.

DESIGN

Observational retrospective cohort study of microbiologic etiologies of ventilator-associated pneumonia from 1998 to 2001 in a multi-hospital system. Microbiologic results were compared between hospitals and between different intensive care units (ICUs) within hospitals.

SETTING

Three hospitals--one pediatric teaching hospital, one adult teaching hospital, and one community hospital--in one healthcare system in the midwestern United States.

PATIENTS

Patients at the target hospitals who developed ventilator-associated pneumonia and for whom microbiologic data were available.

RESULTS

Seven hundred fifty-three episodes of ventilator-associated pneumonia had culture data available for review. The most common organisms at all hospitals were Staphylococcus aureus (28.4%) and Pseudomonas aeruginosa (25.2%). The pediatric hospital had higher proportions of Escherichia coli (9.5% vs 2.3%; P < .001) and Klebsiella pneumoniae (13% vs 3.1%; P < .001) than did the adult hospitals. In the pediatric hospital, the pediatric ICU had higher P aeruginosa rates than did the neonatal ICU (33.3% vs 17%; P = .01). In the adult hospitals, the surgical ICU had higher Acinetobacter baumannii rates (10.2% vs. 1.7%; P < .001) than did the other ICUs.

CONCLUSIONS

Microbiologic etiologies of ventilator-associated pneumonia vary between and within hospitals. Knowledge of these differences can improve selection of initial antimicrobial regimens, which may decrease mortality.

Environmental insults: smoke inhalation, submersion, diving, and high altitude

In the expanding search for recreation, we spend more and more of our time in various environments. Whether the air is thin or compressed or smoke-filled or there is no air at all, emergency physicians continue to meet and treat the various pulmonary emergencies that the environment may create. The authors present the background, diagnosis, and management of a few of the more common pulmonary emergencies that the environment may produce.

Pharmaceutical strategies to prevent ventilator-associated pneumonia

The increasing incidence of hospital-acquired (nosocomial) infection is a disturbing phenomenon resulting in significant patient mortality and putting considerable strain on healthcare budgets and personnel. One particularly serious aspect of nosocomial infection is that of ventilator-associated pneumonia (VAP). This arises in patients who receive mechanical ventilation within the intensive care unit. The quoted incidence of VAP varies widely (5-67%) and the reported mortality of patients with VAP is in the range of 24-71%. This review will examine the many factors that account for these wide ranges reported, including the patient population under investigation, the causative organism, the method of diagnosis, interventions employed and preventative strategies. The use of bioactive and drug-impregnated biomaterials for endotracheal tube construction is discussed as novel approaches to the prevention of VAP.

Experience with a clinical guideline for the treatment of ventilator-associated pneumonia

OBJECTIVE

To evaluate a clinical guideline for the treatment of ventilator-associated pneumonia.

DESIGN

Prospective before-and-after study design.

SETTING

A medical intensive care unit from a university-affiliated, urban teaching hospital.

PATIENTS

Between April 1999 and January 2000, 102 patients were prospectively evaluated.

INTERVENTIONS

Prospective patient surveillance, data collection, and implementation of an antimicrobial guideline for the treatment of ventilator-associated pneumonia.

MEASUREMENTS AND MAIN RESULTS

The main outcome evaluated was the initial administration of adequate antimicrobial treatment as determined by respiratory tract cultures. Secondary outcomes evaluated included the duration of antimicrobial treatment for ventilator-associated pneumonia, hospital mortality, intensive care unit and hospital lengths of stay, and the occurrence of a second episode of ventilator-associated pneumonia. Fifty consecutive patients with ventilator-associated pneumonia were evaluated in the before period and 52 consecutive patients with ventilator-associated pneumonia were evaluated in the after period. Severity of illness using Acute Physiology and Chronic Health Evaluation II (25.8 +/- 5.7 vs. 25.4 +/- 8.1, p =.798) and the clinical pulmonary infection scores (6.6 +/- 1.0 vs. 6.9 +/- 1.2, p =.105) were similar for patients during the two treatment periods. The initial administration of adequate antimicrobial treatment was statistically greater during the after period compared with the before period (94.2% vs. 48.0%, p <.001). The duration of antimicrobial treatment was statistically shorter during the after period compared with the before period (8.6 +/- 5.1 days vs. 14.8 +/- 8.1 days, p <.001). A second episode of ventilator-associated pneumonia occurred statistically less often among patients in the after period (7.7% vs. 24.0%, p =.030).

CONCLUSIONS

The application of a clinical guideline for the treatment of ventilator-associated pneumonia can increase the initial administration of adequate antimicrobial treatment and decrease the overall duration of antibiotic treatment. These findings suggest that similar types of guidelines employing local microbiological data can be used to improve overall antibiotic utilization for the treatment of ventilator-associated pneumonia.

Treatment of nosocomial postoperative pneumonia in cancer patients: a prospective randomized study

BACKGROUND

Nosocomial pneumonia continues to be associated with high morbidity and mortality in cancer patients.

METHODS

In an attempt to find an optimal treatment for this infection, nonneutropenic cancer patients with postoperative nosocomial pneumonia were randomized to receive either piperacillin/tazobactam (P/T) 4.5 g i.v. every 6 hours (30 patients) or clindamycin (Cl) 900 mg plus aztreonam (Az) 2 g i.v. every 8 hours (22 patients). Amikacin 500 mg i.v. every 12 hours was given to all patients for the first 48 hours.

RESULTS

The two groups were comparable for the characteristics of pneumonia that included gram-negative etiology and duration of intubation. Response rates were 83% for patients who received P/T and 86% for those who received Cl/Az (P > .99). There were no serious adverse events; however, at our center the cost of the P/T regimen was $73.86 compared with $99.15 for the Cl/Az regimen.

CONCLUSIONS

The two regimens had comparable high efficacy, and P/T had a slight cost advantage. Either of these antibiotic regimens combined with an aminoglycoside could lead to favorable outcome in cancer patients at high risk for nosocomial pneumonia.

Acid instillation enhances the inflammatory response to subsequent lipopolysaccharide challenge in rats

Aspiration of gastric contents is one of leading causes of the acute respiratory distress syndrome (ARDS). The pathogenesis of acid aspiration-induced acute lung injury is well understood. Less clear is why patients who have suffered acid aspiration are susceptible to ARDS. We studied the effects of acid instillation on the inflammatory response to subsequent lipopolysaccharide (LPS) challenge in rats. Instillation of acid into the right lung worsened the pathology induced by LPS that was administered 24 h after acid instillation. This included worsened oxygenation, increased pulmonary edema, increased production of tumor necrosis factor-alpha (TNF-alpha) and cytokine-induced neutrophil chemoattractant, neutrophil accumulation and mobilization to the alveolar spaces, and nitric oxide (NO) production. Of interest, neutrophil mobilization, NO production, and protein permeability were also magnified in the left lung. These effects were attenuated by administration of the protein tyrosine kinase (PTK) inhibitors genistein and tyrphostin AG556. These data suggest that acid instillation primes the rat to enhance the inflammatory response to subsequent endotoxin challenge and that at least part of the augmented inflammatory response depends on PTK.

Correlation between endotoxin level and bacterial count in bronchoalveolar lavage fluid of ventilated patients

OBJECTIVE

To assess the predictive value of the endotoxin level in the bronchoalveolar lavage (BAL) and to propose to the clinician a guide in the diagnosis of gram-negative bacterial (GNB) pneumonia.

DESIGN

Retrospective and prospective studies to investigate the relation between endotoxin level and quantitative bacterial culture of BAL and to test the predictive value of a defined threshold.

SETTING

University hospital general intensive care unit.

PATIENTS

In the first part of the study, 77 consecutive ventilated patients with clinical suspicion of nosocomial pneumonia between January 1995 and January 1996. In the second part of the study, 93 consecutive ventilated patients studied prospectively between February 1996 and April 1997.

MEASUREMENTS AND MAIN RESULTS

Quantitative cultures for aerobic bacteria were performed directly from the fluid. Bacterial species were determined with standard techniques. The detection of endotoxin in BAL was made using a quantitative chromogenic Limulus assay. In the retrospective analysis, a significant correlation between quantitative GNB cultures and BAL endotoxin levels was observed (r2 = 0.60, p < .0001). An endotoxin level > or = 4 endotoxin units/mL (EU/mL) distinguishes patients with a significant GNB count from colonized patients with a sensitivity of 92.6%, a specificity of 81.4% and a correct classification rate of 84.9%. In the prospective analysis, the 4 EU/mL threshold permits identification of infected patients with a sensitivity of 82.2%, a specificity of 95.6%, and a correct classification rate of 90.3%. The receiver operating characteristic curve analysis showed that the Limulus assay still had a good discrimination power in the prediction of significant bacterial count in BAL fluid.

CONCLUSIONS

Endotoxin detection immediately after bronchoscopy is a distinct advantage to the clinician because antimicrobial gram-negative therapy may be immediately justified according to the results.

Nosocomial Infections in the Surgical Intensive Care Unit: A Difference between Trauma and Surgical Patients

In 1970, the Centers for Disease Control and Prevention (CDC) established the National Nosocomial Infection Surveillance System to assist institutions with infection surveillance, data collection, and processing. This facilitates interinstitutional comparison for nosocomial infection rates. Nosocomial infection rates in the surgical intensive care unit have been shown to be different from the medical intensive care unit. Whether there exists a difference in infection rates between trauma and surgical patients in the intensive care unit has not been established. Our objective was to determine whether there is a difference in rates of nosocomial infections between trauma and surgical patients in the surgical intensive care unit. From January 1995 through December 1997, we reviewed 3715 admissions to the surgical intensive care unit and separated them into trauma (1272) or surgical (2443) cases. We documented all nosocomial pneumonias, urinary tract infections, bloodstream infections, and surgical site infections. From these data we determined infection rates per 100 admissions. We also identified all device-related nosocomial infections and calculated infection rate by current CDC standards using number of device infections divided by number of device-days times 1000. We found that the overall trauma patient infection rate was 11.64 per cent compared with 6.43 per cent for surgical patients (P < .001). Using conventional infection rate criteria, trauma patients had higher frequency in the rate of ventilator-associated pneumonia (6.13% vs 2.50%; P < 0.001), urinary tract infection (2.36 versus 1.76; P < 0.2), and bloodstream infection (2.52% versus 1.27%; P < 0.01). However, when using the CDC guidelines, which correct for the number of device-days for infections, only the difference in rate of pneumonia between the two groups reached statistical significance (23.9 rate for trauma patients vs 16.7 for the surgery group; P < 0.005). We conclude that trauma patients are at higher risk for nosocomial infections than routine surgical patients. Because of this difference, centers should collect and report data separately for trauma and surgical patients in the intensive care unit. Specific attention should be focused on the causes and prevention of increased rates of nosocomial pneumonia in trauma patients.

Epidemiology and risk factors for nosocomial pneumonia. Emphasis on prevention

VAP is a complex nosocomial infection, the disease expression and resulting patient outcome of which is dependent on host factors, the causative organism, the timing and adequacy of treatment, and the presence of intrinsic or inducible antibiotic resistance. Significant improvements have been achieved in our ability to reduce the occurrence of VAP in the hospital setting. Clinicians caring for mechanically ventilated patients should strive to develop focused programs for the prevention of VAP, other nosocomial infections, and the occurrence of antibiotic-resistant infections at their institutions. The benefits of such programs are well demonstrated. The components of a PDSA (Plan-Do-STUDY-Act) model that can be simply employed to develop a VAP prevention program are as follows: Stages Plan: 1. Identify potentially modifiable risk factors for VAP at the institutional level. 2. Develop a strategy to modify or prevent the occurrence of these risk factors. [figure: see text] Do: 1. Carry out the planned intervention strategy. 2. Identify problems in the implementation of the designed intervention. 3. Update the intervention with solutions for the identified problems. 4. Collect basic data (e.g., VAP rates, severity of illness).

STUDY

1. Analyze data. 2. Summarize the results. Act: 1. Determine the overall success or failure of the intervention. 2. Identify potential modifications to improve the intervention strategy. 3. Prepare for next PDSA cycle. Inherent in the development and application of such programs is the concept that they are continuous processes striving to improve clinical performance over time (Fig. 3). At any given institution, the most likely approach to the prevention of NP and VAP will be a multifaceted one, employing interventions aimed at reducing the occurrence of aerodigestive tract colonization with pathogenic bacteria and aspiration. To be successful, such quality improvement programs must be embraced at the institutional level. Only in this way can hospitals hope to successfully reduce their rates of VAP and sustain or improve upon those efforts over time.

Diagnosis of ventilator-associated pneumonia

The diagnosis of ventilator-associated pneumonia (VAP) is problematic despite numerous attempts at defining acceptable diagnostic criteria and the optimal technique for routine respiratory sampling. Clinical criteria have imperfect diagnostic reliability in ventilated patients, but remain crucial for defining those patients who may require respiratory sampling. Quantitative clinical scoring systems may improve the accuracy of clinical diagnosis in some ventilated patients. Review of published studies suggest that fibreoptic bronchoscopic techniques have greater diagnostic reliability than qualitative endotracheal aspirates, despite inconsistent results when comparing the same techniques in different centres. However, the cost and invasive nature of bronchoscopic methods precludes their use as first-line techniques in VAP. Non-bronchoscopic, non-directed techniques are cheaper, safer and more widely available alternatives to fibreoptic bronchoscopy techniques and have comparable accuracy. Quantitation of respiratory tract cultures is useful in excluding VAP in patients with equivocal signs of pneumonia. The diagnostic threshold of bacterial load that defines the presence of VAP should vary according to the pre-test probability of pneumonia, length of ventilation, antibiotic administration and immunocompetence of the patient.