The spectrum of practice in the diagnosis and management of pneumonia in patients requiring mechanical ventilation. Australian and New Zealand practice in intensive care (ANZPIC II)

Disease Risk and Mortality Prediction in Intensive Care Patients with Pneumonia. Australian and New Zealand Practice in Intensive Care (ANZPIC II)

This study of ventilated patients investigated pneumonia risk factors and outcome predictors in 476 episodes of pneumonia (48% community-acquired pneumonia, 24% hospital-acquired pneumonia, 28% ventilator-associated pneumonia) using a prospective survey in 14 intensive care units within Australia and New Zealand. For community acquired pneumonia, mortality increased with immunosuppression (OR 5.32, CI 95% 1.58–17.99, P<0.01), clinical signs of consolidation (OR 2.43, CI 95% 1.09–5.44, P=0.03) and Sepsis-Related Organ Failure Assessment (SOFA) scores (OR 1.19, CI 95% 1.08–1.30, P<0.001) but improved if appropriate antibiotic changes were made within three days of intensive care unit admission (OR 0.42, CI 95% 0.20–0.86, P=0.02). For hospital-acquired pneumonia, immunosuppression (OR 6.98, CI 95% 1.16–42.2, P=0.03) and non-metastatic cancer (OR 3.78, CI 95% 1.20–11.93, P=0.02) were the principal mortality predictors. Alcoholism (OR 7.80, CI 95% 1.20–17.50, P<0.001), high SOFA scores (OR 1.44, CI 95% 1.20–1.75, P=0.001) and the isolation of “high risk” organisms including Pseudomonas aeruginosa, Acinetobacter spp, Stenotrophomonas spp and methicillin resistant Staphylococcus aureus (OR 4.79, CI 95% 1.43–16.03, P=0.01), were associated with increased mortality in ventilator-associated pneumonia. The use of non-invasive ventilation was independently protective against mortality for patients with community-acquired and hospital-acquired pneumonia (OR 0.35, CI 95% 0.18–0.68, P=0.002). Mortality was similar for patients requiring both invasive and non-invasive ventilation and non-invasive ventilation alone (21% compared with 20% respectively, P=0.56).

Pneumonia risks and mortality predictors in Australian and New Zealand ICUs vary with pneumonia type. A history of alcoholism is a major risk factor for mortality in ventilator-associated pneumonia, greater in magnitude than the mortality effect of immunosuppression in hospital-acquired pneumonia or community-acquired pneumonia. Non-invasive ventilation is associated with reduced ICU mortality. Clinical signs of consolidation worsen, while rationalising antibiotic therapy within three days of ICU admission improves mortality for community-acquired pneumonia patients.

Quality of the aetiological diagnosis of ventilator-associated pneumonia in Spain in the opinion of intensive care specialists and microbiologists

INTRODUCTION

Current guidelines for the microbiological diagnosis of ventilator-associated pneumonia (VAP) are imprecise. Based on data provided by intensive care specialists (ICS) and microbiologists, this study defines the clinical practices and microbiological techniques currently used for an aetiological diagnosis of VAP and pinpoints deficiencies.

METHODS

Eighty hospitals in the national health network with intensive care and microbiology departments were sent two questionnaires, one for each department, in order to collect data on VAP diagnosis for the previous year.

RESULTS

Out of the 80 hospitals, 35 (43.8%) hospitals participated. These included 673 ICU beds, 32,020 ICU admissions, 173,820 ICU days stay, and generated 27,048 lower respiratory tract specimens in the year. A third of the hospitals (35%) had a microbiology department available 24/7. Most samples (83%) were tracheal aspirates. Gram stain results were immediately reported in around half (47%) of the hospitals. Quantification was made in 75% of hospitals. Molecular techniques and direct susceptibility testing were performed in 12% and one institution, respectively. Mean turnaround time for a microbiological report was 1.7 (SD; 0.7), and 2.2 (SD; 0.6) days for a negative and positive result, respectively. Telephone/in-person information was offered by 65% of the hospitals. Most (89%) ICS considered microbiological information as very useful. No written procedures were available in half the ICUs.

CONCLUSIONS

Both ICS and microbiologists agreed that present guidelines for the diagnosis of VAP could be much improved, and that a new set of consensus guidelines is urgently required. A need for guidelines to be more effectively implemented was also identified in order to improve outcomes in patients with VAP.

Is inhaled prophylactic heparin useful for prevention and management of pneumonia in ventilated ICU patients?

PURPOSE

The purpose was to determine the efficacy of prophylactic inhaled heparin for the prevention and treatment of pneumonia in patients receiving mechanical ventilation (MV).

METHODS

A phase 2, double-blind, randomized controlled trial stratified for study center and patient type (nonoperative, postoperative) was conducted in 3 university-affiliated intensive care units. Patients aged at least 18 years and requiring invasive MV for more than 48 hours were randomized to usual care, nebulization of unfractionated sodium heparin (5000 U in 2 mL), or nebulization with 0.9% sodium chloride (2 mL) 4 times daily with the main outcome measures, the development of ventilator-associated pneumonia (VAP), ventilator-associated complication, and Sequential Organ Failure Assessment scores in patients with admission pneumonia or developing VAP.

TRIAL REGISTRATION

ACTRN12612000038897.

RESULTS

A total of 214 patients were enrolled (72 usual care, 71 inhaled sodium heparin, 71 inhaled sodium chloride). There were no differences between treatment groups in terms of the development of VAP using either Klompas criteria (6%-7%, P=1.00) or clinical diagnosis (24%-26%, P=.85).

CONCLUSION

Low-dose nebulized heparin cannot be recommended for prophylaxis against VAP or to hasten recovery from pneumonia in patients receiving MV.

Is inhaled prophylactic heparin useful for prevention and Management of Pneumonia in ventilated ICU patients?: The IPHIVAP investigators of the Australian and New Zealand Intensive Care Society Clinical Trials Group

PURPOSE

To determine whether prophylactic inhaled heparin is effective for the prevention and treatment of pneumonia patients receiving mechanical ventilation (MV) in the intensive care unit.

METHODS

A phase 2, double blind randomized controlled trial stratified for study center and patient type (non-operative, post-operative) was conducted in three university-affiliated intensive care units. Patients aged ≥18years and requiring invasive MV for more than 48hours were randomized to usual care, nebulization of unfractionated sodium heparin (5000 units in 2mL) or placebo nebulization with 0.9% sodium chloride (2mL) four times daily with the main outcome measures of the development of ventilator associated pneumonia (VAP), ventilator associated complication (VAC) and sequential organ failure assessment scores in patients with pneumonia on admission or who developed VAP.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ACTRN12612000038897.

RESULTS

Two hundred and fourteen patients were enrolled (72 usual care, 71 inhaled sodium heparin, 71 inhaled sodium chloride). There were no differences between treatment groups in terms of the development of VAP, using either Klompas criteria (6-7%, P=1.00) or clinical diagnosis (24-26%, P=0.85). There was no difference in the clinical consistency (P=0.70), number (P=0.28) or the total volume of secretions per day (P=.54). The presence of blood in secretions was significantly less in the usual care group (P=0.005).

CONCLUSION

Nebulized heparin cannot be recommended for prophylaxis against VAP or to hasten recovery from pneumonia in patients receiving MV.

Antimicrobial Utilisation in 37 Australian and New Zealand Intensive Care Units

This multi-centre point prevalence study reports on antimicrobial dosing patterns, including dose, mode of administration and type of infection, in 37 Australian and New Zealand intensive care units. Of 422 patients admitted to an intensive care unit on 8 May 2007, 195 patients (46%) received antimicrobial treatment, 123 patients (29%) received no antimicrobials and 104 patients (25%) received prophylactic antimicrobials only. Dosing data were available for 331 antimicrobials used to treat 225 infections in 193 patients. Respiratory (40%), abdominal (13%) and blood stream (12%) infections were most common. For adult patients, ticarcillin/clavulanate (23% or 40/177), meropenem (20% or 35/177) and vancomycin (18% or 32/177) were the most frequently used antibiotics; vancomycin was most commonly used in children (31% or 5/16). The majority of antimicrobials were administered as bolus doses or infusions of less than two hours (98% or 317/323); only six patients received extended or continuous infusions. The mode of administration was unknown in eight cases (4.1%). The total defined daily dose for adult patients receiving antimicrobial therapy was 2051 defined daily doses per 1000 patient days. Our results confirm that the use of continuous infusions remains rare, despite increased interest in continuous infusions for time-dependent antibiotics.

Diagnosis, management and prevention of ventilator-associated pneumonia: an update

Ventilator-associated pneumonia (VAP) affects 10-20% of mechanically ventilated patients and is associated with increased morbidity and mortality and high costs. Early diagnosis is crucial for rapid appropriate antimicrobial therapy to be instituted, but debate remains as to the optimal diagnostic strategy. Noninvasive clinical-based diagnosis is rapid but may not be as accurate as invasive techniques. Increased use of biomarkers and advances in genomics and proteomics may help speed up diagnosis. Management of VAP relies principally on appropriate antimicrobial therapy, which should be selected according to individual patient factors, such as previous antibacterial therapy and length of hospitalization or mechanical ventilation, and local infection and resistance patterns. In addition, once bacterial culture and sensitivity results are available, broad-spectrum therapy should be de-escalated to provide a more specific, narrower-spectrum cover. Optimum duration of antibacterial therapy is difficult to define and should be tailored to clinical response. Biomarker levels may be useful to monitor response to therapy. With the high morbidity and mortality, prevention of VAP is important and several strategies have been shown to reduce the rates of VAP in mechanically ventilated patients, including using noninvasive ventilation where possible, and semi-recumbent positioning. Other potentially beneficial preventive techniques include subglottal suctioning, oral decontamination strategies and antimicrobial-coated endotracheal tubes, although further study is needed to confirm the cost effectiveness of these strategies.

Systematic review and meta-analysis of the efficacy of appropriate empiric antibiotic therapy for sepsis

Quantifying the benefit of early antibiotic treatment is crucial for decision making and can be assessed only in observational studies. We performed a systematic review of prospective studies reporting the effect of appropriate empirical antibiotic treatment on all-cause mortality among adult inpatients with sepsis. Two reviewers independently extracted data. Risk of bias was assessed using the Newcastle-Ottawa score. We calculated unadjusted odds ratios (ORs) with 95% confidence intervals for each study and extracted adjusted ORs, with variance, methods, and covariates being used for adjustment. ORs were pooled using random-effects meta-analysis. We examined the effects of methodological and clinical confounders on results through subgroup analysis or mixed-effect meta-regression. Seventy studies were included, of which 48 provided an adjusted OR for inappropriate empirical antibiotic treatment. Inappropriate empirical antibiotic treatment was associated with significantly higher mortality in the unadjusted and adjusted comparisons, with considerable heterogeneity occurring in both analyses (I(2) > 70%). Study design, time of mortality assessment, the reporting methods of the multivariable models, and the covariates used for adjustment were significantly associated with effect size. Septic shock was the only clinical variable significantly affecting results (it was associated with higher ORs). Studies adjusting for background conditions and sepsis severity reported a pooled adjusted OR of 1.60 (95% confidence interval = 1.37 to 1.86; 26 studies; number needed to treat to prevent one fatal outcome, 10 patients [95% confidence interval = 8 to 15]; I(2) = 46.3%) given 34% mortality with inappropriate empirical treatment. Appropriate empirical antibiotic treatment is associated with a significant reduction in all-cause mortality. However, the methods used in the observational studies significantly affect the effect size reported. Methods of observational studies assessing the effects of antibiotic treatment should be improved and standardized.

Ventilator-associated pneumonia in trauma patients is associated with lower mortality: results from EU-VAP study

BACKGROUND

Differences in trauma patients developing ventilator-associated pneumonia (VAP) are described regarding etiology and risk factors associated. We aim to describe the differences in outcomes in trauma and nontrauma patients with VAP.

METHODS

A prospective, observational study conducted in 27 intensive care units from nine European countries. We included patients requiring invasive mechanical ventilation for >48 hours who developed VAP. Logistic regression model was used to assess the factors independently associated with mortality in trauma patients with VAP.

RESULTS

A total of 2,436 patients were evaluated; 465 developed VAP and of these 128 (27.5%) were trauma patients. Trauma patients were younger than nontrauma (45.3 ± 19.4 vs. 61.1 ± 16.7, p < 0.0001). Nontrauma had higher simplified acute physiology score II compared with trauma patients (45.5 ± 16.3 vs. 41.1 ± 15.2, p = 0.009). Most prevalent pathogens in trauma patients with early VAP were Enterobacteriaceae spp. (46.9% vs. 27.8%, p = 0.06) followed by methicillin-susceptible Staphylococcus aureus (30.6% vs. 13%, p = 0.03) and then Haemophilus influenzae (14.3% vs. 1.9%, p = 0.02), and the most prevalent pathogen in late VAP was Acinetobacter baumannii (12.2% vs. 44.4%, p < 0.0001). Mortality was higher in nontrauma patients than in trauma patients (42.6% vs. 17.2%, p < 0.001, odds ratio [OR] = 3.55, 95%CI = 2.14-5.88). A logistic regression model adjusted for sex, age, severity of illness at intensive care unit admission, and sepsis-related organ failure assessment score at the day of VAP diagnosis confirmed that trauma was associated with a lower mortality compared with nontrauma patients (odds ratio [OR] = 0.37, 95%CI = 0.21-0.65).

CONCLUSIONS

Trauma patients developing VAP had different demographic characteristics and episodes of etiology. After adjustment for potential confounders, VAP episodes in trauma patients are associated with lower mortality when compared with nontrauma patients.

Spectrum of practice in the diagnosis of nosocomial pneumonia in patients requiring mechanical ventilation in European intensive care units

OBJECTIVES

Information on clinical practice regarding the diagnosis of pneumonia in European intensive care units is limited. The aim of this study was to describe the spectrum of actual diagnostic practices in a large sample of European intensive care units.

DESIGN

Prospective, observational, multicenter study.

SETTING

Twenty-seven intensive care units of nine European countries.

PATIENTS

Consecutive patients requiring invasive mechanical ventilation for an admission diagnosis of pneumonia or receiving mechanical ventilation for >48 hrs irrespective of admission diagnosis.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 2,436 patients were evaluated; 827 were admitted with or developed nosocomial pneumonia (hospital-acquired pneumonia [HAP], 27.1%; ventilator-associated pneumonia [VAP], 56.2%; very early onset VAP, 16.7%). Mean age was 59.4 +/- 18.1 yrs, 65.0% were men, and mean admission Simplified Acute Physiology Score II was 46.7 +/- 17.1. Worsening oxygenation (76.8%), purulent/changing respiratory secretions (72.1%), and new temperature elevation (69.2%) were the most frequent clinical signs of nosocomial pneumonia. Etiological diagnosis was based on noninvasive respiratory specimens in 74.8% of episodes. Bronchoscopy was performed in 23.3% of episodes. Bronchoscopy performance, after adjustment by severity of illness, age, and type of hospital, were predicted by worsening oxygenation (odds ratio 2.03; 95% confidence interval, 1.27-3.24) and male sex (odds ratio 1.77; 95% confidence interval, 1.19-2.65). Definite cause was documented in 69.5% of nosocomial pneumonia cases. The most common isolates were Staphylococcus aureus (16.3% methicillin-sensitive S. aureus and 16.0% methicillin-resistant S. aureus), Pseudomonas aeruginosa (23.1%), and Acinetobacter baumannii (19.1%). Presence of nosocomial pneumonia significantly prolonged mean length of mechanical ventilation (10.3 days, p < .05) and mean intensive care unit length of stay (12.2 days, p < .05) in intensive care unit survivors. Mortality rate was 37.7% for nosocomial pneumonia vs. 31.6% for patients without pneumonia (p < .05).

CONCLUSIONS

Etiological diagnosis of nosocomial pneumonia in a large sample of European intensive care units was based mainly on noninvasive techniques. However, there was high variability in bronchoscopy use between the participating intensive care units.

Surveillance culture utility and safety using low-volume blind bronchoalveolar lavage in the diagnosis of ventilator-associated pneumonia

BACKGROUND AND OBJECTIVES

Surveillance cultures may improve the prediction of ventilator-associated pneumonia (VAP) and empirical antibiotic selection. This study examined the utility and patient safety of blind, non-protected, low-volume mini-bronchial lavage (BM-BAL) surveillance cultures in predicting VAP.

METHODOLOGY

A prospective, cohort study was performed in a large general intensive care unit. BM-BALs were collected within 12 h of admission then thrice weekly. Each BM-BAL was screened by Gram staining for intracellular organisms and then quantitatively cultured. VAP was diagnosed using the Clinical Pulmonary Infection Score. The concordance for isolates from the BM-BAL was assessed against concurrently collected endotracheal aspirates (EA).

RESULTS

Four hundred and twelve patients requiring a minimum of 48 h of mechanical ventilation were enrolled. Fifty patients developed 58 episodes of VAP. Concordant pathogens were found in 85% of BM-BAL specimens collected 2 days prior to VAP onset. Their antibiograms were stable over the preceding 4 days. The isolation of pathogens with colony counts >or=10(4) cfu/mL from BM-BAL performed 2 days prior to the clinical onset of VAP had a sensitivity of 84%, specificity of 50%, positive predictive value of 31% and a negative predictive value of 93% for predicting the development of VAP. BM-BAL WCC, quantification of bacterial growth and the percentage of intracellular organisms were not helpful in predicting VAP diagnosis.

CONCLUSIONS

BM-BAL surveillance cultures are well tolerated and useful in predicting the pathogens and their antibiograms causing VAP. Diagnostic specimen collection at the time of VAP onset is still required as surveillance cultures may be negative even one day prior to VAP onset.

Nosocomial pneumonia: aetiology, diagnosis and treatment

PURPOSE OF REVIEW

This review highlights recent advances in the aetiology of nosocomial pneumonia, and in strategies to increase accuracy of diagnosis and antibiotic prescription while limiting unnecessary antibiotic consumption.

RECENT FINDINGS

Bacterial pathogens still cause the bulk of nosocomial pneumonia and are of concern because of ever-rising antimicrobial resistance. Yet, the pathogenic role of fungal and viral organisms is increasingly recognized. Since early appropriate antimicrobial therapy is the cornerstone of an effective treatment, further studies have been conducted to improve appropriateness of early antibiotic therapy. De-escalation strategies combine initial broad-spectrum antibiotics to maximize early antibiotic coverage with a subsequent focusing of the antibiotic spectrum when the cause is identified. Invasive techniques probably do not alter the immediate outcome but have the potential to reduce unnecessary antibiotic exposure. Decisions to stop or change antibiotic therapy are hampered due to a lack of reliable parameters to assess the resolution of pneumonia.

SUMMARY

Increasing antimicrobial resistance in nosocomial pneumonia both challenges treatment and mandates limitation of selection pressure by reducing antibiotic burden. Treating physicians should be both aggressive in initiating antimicrobials when suspecting nosocomial pneumonia but willing to discontinue antimicrobials when diagnostic results point to an alternative diagnosis. Efforts should be made to limit duration of antibiotic therapy when possible.

Gram-negative bacterial pneumonia: aetiology and management

PURPOSE OF REVIEW

Recent articles of clinical and investigational interest on Gram-negative pneumonia, particularly hospital-acquired and ventilator-associated pneumonia, are reviewed.

RECENT FINDINGS

The high rate of respiratory infections due to Gram-negative bacteria in late-onset ventilator-associated pneumonia has been repeatedly documented. The predominant pathogens are Pseudomonas aeruginosa and Acinetobacter baumannii. On the other hand, the frequency of Gram-negative bacteria in community-acquired pneumonia and in early-onset ventilator-associated pneumonia is increasing. Patients with risk factors for infection with resistant pathogens should initially receive a combination therapy that covers a broad spectrum, and, as soon as the pathogen and the susceptibilities are available, treatment should be simplified to a more targeted one (with the possible exception of P. aeruginosa pneumonia). Adequate dosing is of great importance and the use of pharmacodynamic/pharmacokinetic principles when prescribing antibiotics increases effectiveness. The optimal duration of therapy remains unknown; several studies have supported the use of shorter courses of treatment. Alternative treatment approaches (e.g. vaccines) are under investigation.

SUMMARY

The increasing frequency of resistant Gram-negative bacteria and the shortage of newer antibiotics in the pipeline with activity against Gram-negative bacteria is of concern. Early effective antimicrobial treatment is a key for the resolution of infection and improved survival.