Causes and predictors of nonresponse to treatment of intensive care unit–acquired pneumonia*

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

An Adjudication Protocol for Severe Pneumonia

Background

Clinical end points that constitute successful treatment in severe pneumonia are difficult to ascertain and vulnerable to bias. The utility of a protocolized adjudication procedure to determine meaningful end points in severe pneumonia has not been well described.

Methods

This was a single-center prospective cohort study of patients with severe pneumonia admitted to the medical intensive care unit. The objective was to develop an adjudication protocol for severe bacterial and/or viral pneumonia. Each episode of pneumonia was independently reviewed by 2 pulmonary and critical care physicians. If a discrepancy occurred between the 2 adjudicators, a third adjudicator reviewed the case. If a discrepancy remained after all 3 adjudications, consensus was achieved through committee review.

Results

Evaluation of 784 pneumonia episodes during 593 hospitalizations achieved only 48.1% interobserver agreement between the first 2 adjudicators and 78.8% when agreement was defined as concordance between 2 of 3 adjudicators. Multiple episodes of pneumonia and presence of bacterial/viral coinfection in the initial pneumonia episode were associated with lower interobserver agreement. For an initial episode of bacterial pneumonia, patients with an adjudicated day 7-8 clinical impression of cure (compared with alternative impressions) were more likely to be discharged alive (odds ratio, 6.3; 95% CI, 3.5-11.6).

Conclusions

A comprehensive adjudication protocol to identify clinical end points in severe pneumonia resulted in only moderate interobserver agreement. An adjudicated end point of clinical cure by day 7-8 was associated with more favorable hospital discharge dispositions, suggesting that clinical cure by day 7-8 may be a valid end point to use in adjudication protocols.

Defining Clinical and Microbiological Nonresponse in Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a severe complication of mechanical ventilation, with mortality reduced most effectively by adequate early antibiotic treatment. The clinical and microbiologic response can be assessed easily from 72 hours after starting antibiotic treatment. Evidence of nonresponse is based on several factors: (1) lack of clinical improvement, (2) radiographic progression, (3) an impaired Sequential Organ Failure Assessment (SOFA) score, (4) no improvement by days 3 to 5 on the Clinical Pulmonary Infection Score (CPIS), (5) no decreased in biomarkers on day 3, and (6) isolation of a new pathogen on day 3. Among the clinical markers of treatment failure, physicians should consider no improvement in the ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO₂/FiO₂), persistence of fever or hypothermia, persistence of purulent respiratory secretions, and new-onset septic shock or multiple-organ dysfunction syndrome. Microbiological isolation of a new pathogen on day 3 is also associated with higher mortality, but persistence of the original pathogen does not seem to be associated with a worse prognosis. The real impact of changes to treatment after diagnosing nonresponsive VAP is unknown. Physicians must evaluate whether treatments are adequate in terms of sensitivity, dose, and route. Pharmacokinetically and pharmacodynamically optimized doses are recommended in these patients. Clinical stabilization of comorbidities or underlying conditions may be of benefit.

Genetic Regulation of Cytokine Response in Patients with Acute Community-Acquired Pneumonia

Background: Community-acquired pneumonia (CAP) is an acute disease condition with a high risk of rapid deteriorations. We analysed the influence of genetics on cytokine regulation to obtain a better understanding of patient’s heterogeneity. Methods: For up to N = 389 genotyped participants of the PROGRESS study of hospitalised CAP patients, we performed a genome-wide association study of ten cytokines IL-1β, IL-6, IL-8, IL-10, IL-12, MCP-1 (MCAF), MIP-1α (CCL3), VEGF, VCAM-1, and ICAM-1. Consecutive secondary analyses were performed to identify independent hits and corresponding causal variants. Results: 102 SNPs from 14 loci showed genome-wide significant associations with five of the cytokines. The most interesting associations were found at 6p21.1 for VEGF (p = 1.58 × 10⁻²⁰), at 17q21.32 (p = 1.51 × 10⁻⁹) and at 10p12.1 (p = 2.76 × 10⁻⁹) for IL-1β, at 10p13 for MIP-1α (CCL3) (p = 2.28 × 10⁻⁹), and at 9q34.12 for IL-10 (p = 4.52 × 10⁻⁸). Functionally plausible genes could be assigned to the majority of loci including genes involved in cytokine secretion, granulocyte function, and cilial kinetics. Conclusion: This is the first context-specific genetic association study of blood cytokine concentrations in CAP patients revealing numerous biologically plausible candidate genes. Two of the loci were also associated with atherosclerosis with probable common or consecutive pathomechanisms.

Cytokine Expression of Lung Bacterial Infection in Newly Diagnosed Adult Hematological Malignancies

Adult patients with hematological malignancies are frequently accompanied by bacterial infections in the lungs when they are first diagnosed. Sputum culture, procalcitonin (PCT), C-reactive protein (CRP), body temperature, and other routinely used assays are not always reliable. Cytokines are frequently abnormally produced in adult hematological malignancies associated with a lung infection, it is uncertain if cytokines can predict lung bacterial infections in individuals with hematological malignancies. Therefore, we reviewed 541 adult patients newly diagnosed with hematological malignancies, of which 254 patients had lung bacterial infections and 287 patients had no other clearly diagnosed infections. To explore the predictive value of cytokines for pulmonary bacterial infection in adult patients with hematological malignancies. Our results show that IL-4, IL-6, IL-8, IL-10, IL-12P70, IL-1β, IL-2, IFN-γ, TNF-α, TNF-β and IL-17A are in the lungs The expression level of bacterially infected individuals was higher than that of patients without any infections (P<0.05). Furthermore, we found that 88.89% (200/225) of patients with IL-6 ≥34.12 pg/ml had a bacterial infection in their lungs. With the level of IL-8 ≥16.35 pg/ml, 71.67% (210/293) of patients were infected. While 66.10% (193/292) of patients had lung bacterial infections with the level of IL-10 ≥5.62 pg/ml. When IL-6, IL-8, and IL-10 were both greater than or equal to their Cutoff-value, 98.52% (133/135) of patients had lung bacterial infection. Significantly better than PCT ≥0.11 ng/ml [63.83% (150/235)], body temperature ≥38.5°C [71.24% (62/87)], CRP ≥9.3 mg/L [53.59% (112/209)] the proportion of lung infection. In general. IL-6, IL-8 and IL-10 are abnormally elevated in patients with lung bacterial infections in adult hematological malignancies. Then, the abnormal increase of IL-6, IL-8 and IL-10 should pay close attention to the possible lung bacterial infection in patients.

Prediction of ventilator-associated pneumonia outcomes according to the early microbiological response: a retrospective observational study

Ventilator-associated pneumonia is a leading infectious cause of morbidity in critically ill patients; yet current guidelines offer no indications for follow-up cultures.We aimed to evaluate the role of follow-up cultures and microbiological response 3 days after diagnosing ventilator-associated pneumonia as predictors of short- and long-term outcomes.We performed a retrospective analysis of a cohort prospectively collected from 2004 to 2017. Ventilator-associated pneumonia was diagnosed based on clinical, radiographic, and microbiological criteria. For microbiological identification, a tracheobronchial aspirate was performed at diagnosis and repeated after 72 h. We defined three groups when comparing the two tracheobronchial aspirate results: persistence, superinfection, and eradication of causative pathogens.One-hundred-fifty-seven patients were enrolled in the study, among whom microbiological persistence, superinfection, and eradication was present in 67 (48%), 25 (16%), and 65 (41%), respectively, after 72hs. Those with superinfection had the highest mortalities in the intensive care unit (p=0.015) and at 90 days (p=0.036), while also having the fewest ventilation-free days (p=0.024). Multivariable analysis revealed shock at VAP diagnosis (odds ratios [OR] 3.43; 95% confidence interval [CI] 1.25 to 9.40), Staphylococcus aureus isolation at VAP diagnosis (OR 2.87; 95%CI 1.06 to 7.75), and hypothermia at VAP diagnosis (OR 0.67; 95%CI 0.48 to 0.95, per +1°C) to be associated with superinfection.Our retrospective analysis suggests that ventilator-associated pneumonia short-term and long-term outcomes may be associated with superinfection in follow-up cultures. Follow-up cultures may help guiding antibiotic therapy and its duration. Further prospective studies are necessary to verify our findings.

Impact of Cardiovascular Failure in Intensive CareUnit-Acquired Pneumonia: A Single-Center, Prospective Study

Background: Cardiovascular failure (CVF) may complicate intensive care unit-acquired pneumonia (ICUAP) and radically alters the empirical treatment of this condition. The aim of this study was to determine the impact of CVF on outcome in patients with ICUAP. Methods: A prospective, single-center, observational study was conducted in six medical and surgical ICUs at a University Hospital. CVS was defined as a score of 3 or more on the cardiovascular component of the Sequential Organ Failure Assessment (SOFA) score. At the onset of ICUAP, CVF was reported as absent, transient (if lasting ≤ 3 days) or persistent (>3 days). The primary outcome was 90-day mortality modelled through a Cox regression analysis. Secondary outcomes were 28-day mortality, hospital mortality, ICU length of stay (LOS) and hospital LOS. Results: 358 patients were enrolled: 203 (57%) without CVF, 82 (23%) with transient CVF, and 73 (20%) with persistent CVF. Patients with transient and persistent CVF were more severely ill and presented higher inflammatory response than those without CVF. Despite having similar severity and aetiology, the persistent CVF group more frequently received inadequate initial antibiotic treatment and presented more treatment failures than the transient CVF group. In the persistent CVF group, at day 3, a bacterial superinfection was more frequently detected. The 90-day mortality was significantly higher in the persistent CVF group (62%). The 28-day mortality rates for patients without CVF, with transient and with persistent CVF were 19, 35 and 41% respectively and ICU mortality was 60, 38 and 19% respectively. In the multivariate analysis chronic pulmonary conditions, lack of Pa0₂/FiO₂ improvement at day 3, pulmonary superinfection at day 3 and persistent CVF were independently associated with 90-day mortality in ICUAP patients. Conclusions: Persistent CVF has a significant impact on the outcome of patients with ICUAP. Patients at risk from persistent CVF should be promptly recognized to optimize treatment and outcomes.

Protocol for an international, multicentre, prospective, observational study of nosocomial pneumonia in intensive care units: the PneumoINSPIRE study

Background: Nosocomial pneumonia in the critical care setting is associated with increased morbidity, significant crude mortality rates and high health care costs. Ventilator-associated pneumonia represents about 80% of nosocomial pneumonia cases in intensive care units (ICUs). Wide variance in incidence of nosocomial pneumonia and diagnostic techniques used has been reported, while successful treatment remains complex and a matter of debate. Objective: To describe the epidemiology, diagnostic strategies and treatment modalities for nosocomial pneumonia in contemporary ICU settings across multiple countries around the world. Design, setting and patients: PneumoINSPIRE is a large, multinational, prospective cohort study of adult ICU patients diagnosed with nosocomial pneumonia. Participating ICUs from at least 20 countries will collect data on 10 or more consecutive ICU patients with nosocomial pneumonia. Site-specific information, including hospital policies on antibiotic therapy, will be recorded along with patient-specific data. Variables that will be explored include: aetiology and antimicrobial resistance patterns, treatment-related parameters (including time to initiation of antibiotic therapy, and empirical antibiotic choice, dose and escalation or de-escalation), pneumonia resolution, ICU and hospital mortality, and risk factors for unfavourable outcomes. The concordance of ventilator-associated pneumonia diagnosis with accepted definitions will also be assessed. Results and conclusions: PneumoINSPIRE will provide valuable information on current diagnostic and management practices relating to ICU nosocomial pneumonia, and identify research priorities in the field. Trial registration:ClinicalTrials.gov identifier NCT02793141.

Dynamics of cytokines, immune cell counts and disease severity in patients with community-acquired pneumonia - Unravelling potential causal relationships

BACKGROUND

Community acquired pneumonia (CAP) is a severe and often rapidly deteriorating disease. To better understand its dynamics and potential causal relationships, we analyzed time series data of cytokines, blood and clinical parameters in hospitalized CAP patients.

METHODS

Time series data of 10 circulating cytokines, blood counts and clinical parameters were related to baseline characteristics of 403 CAP patients using univariate mixed models. Bivariate mixed models were applied to analyze correlations between the time series. To identify potential causal relationships, we inferred cross-lagged relationships between pairs of parameters using latent curve models with structured residuals.

RESULTS

IL-6 levels decreased faster over time in younger patients (P_adj = 0.06). IL-8, VCAM-1, and IL-6 correlated strongly with disease severity as assessed by the sequential organ failure assessment (SOFA) score (r = 0.49, 0.48, 0.46, respectively; all P_adj < 0.001). IL-6 and bilirubin correlated with respect to their mean levels and slopes over time (r = 0.36 and r = 0.46, respectively; P_adj < 0.001). A number of potential causal relationships were identified, e.g., a negative effect of ICAM-1 on MCP-1, or a positive effect of the level of creatinine on the subsequent VCAM-1 concentration (P < 0.001).

CONCLUSIONS

These results suggest that IL-6 trajectories of CAP patients are associated with age and run parallel to bilirubin levels. The time series analysis also unraveled directed, potentially causal relationships between cytokines, blood parameters and clinical outcomes. This will facilitate the development of mechanistic models of CAP, and with it, improvements in treatment or surveillance strategies for this disease.

TRIAL REGISTRATION

clinicaltrials.gov NCT02782013, May 25, 2016, retrospectively registered.

The role of steroids in severe CAP

Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality despite adequate antibiotic therapy. It is the single most common cause of infection-related mortality in the United States. An exaggerated host inflammatory response can potentially be harmful to both the lung and host, and has been associated with treatment failure and mortality. Modulation of inflammatory response may, therefore, be theoretically beneficial. The anti-inflammatory and immunosuppressive effects of steroids seem an attractive therapeutic option in severe CAP patients. Available datapoint to overall shorter time to clinical stability and decreased length-of-stay in CAP patients, with a potential mortality benefit in severe CAP. The level of evidence is, however, low to moderate regarding mortality due to high heterogeneity and insufficient power of data. Furthermore, steroids were deleterious in influenza pneumonia and in patients with pneumococcal pneumonia data suggest a lack of efficacy and potential harm. Both European and American guidelines recommend not using corticosteroids in CAP. Patients who might benefit and those that can be harmed from steroids remain to be clearly identified, as does the ideal steroid for CAP patients, based on pharmacokinetic and pharmacodynamic properties. It is essential for future studies to avoid the same methodological bias present in the available data so that high-quality evidence on the true role of steroids in CAP can be provided.

Ventilator-Associated Pneumonia and PaO2/FIO2 Diagnostic Accuracy: Changing the Paradigm?

Background: Ventilator-associated pneumonia (VAP) is associated to longer stay and poor outcomes. Lacking definitive diagnostic criteria, worsening gas exchange assessed by PaO₂/F_IO₂ ≤ 240 in mmHg has been proposed as one of the diagnostic criteria for VAP. We aim to assess the adequacy of PaO₂/F_IO₂ ≤ 240 to diagnose VAP. Methods: Prospective observational study in 255 consecutive patients with suspected VAP, clustered according to PaO₂/F_IO₂ ≤ 240 vs. > 240 at pneumonia onset. The primary analysis was the association between PaO₂/F_IO₂ ≤ 240 and quantitative microbiologic confirmation of pneumonia, the most reliable diagnostic gold-standard. Results: Mean PaO₂/F_IO₂ at VAP onset was 195 ± 82; 171 (67%) cases had PaO₂/F_IO₂ ≤ 240. Patients with PaO₂/F_IO₂ ≤ 240 had a lower APACHE-II score at ICU admission; however, at pneumonia onset they had higher CPIS, SOFA score, acute respiratory distress syndrome criteria and incidence of shock, and less microbiological confirmation of pneumonia (117, 69% vs. 71, 85%, p = 0.008), compared to patients with PaO₂/FIO₂ > 240. In multivariate logistic regression, PaO₂/FIO₂ ≤ 240 was independently associated with less microbiological confirmation (adjusted odds-ratio 0.37, 95% confidence interval 0.15–0.89, p = 0.027). The association between PaO₂/F_IO₂ and microbiological confirmation of VAP was poor, with an area under the ROC curve 0.645. Initial non-response to treatment and length of stay were similar between both groups, while hospital mortality was higher in patients with PaO₂/F_IO₂ ≤ 240. Conclusion: Adding PaO₂/F_IO₂ ratio ≤ 240 to the clinical and radiographic criteria does not help in the diagnosis of VAP. PaO₂/F_IO₂ ratio > 240 does not exclude this infection. Using this threshold may underestimate the incidence of VAP.

Predictive and prognostic roles of electrical cardiometry in noninvasive assessments of community-acquired pneumonia patients with dyspnoea

Background:

Thoracic impedance monitoring able to detect pneumonia in the very early phase of emerging infiltration prior the patient developed remarkable clinical symptoms. However, no studies have yet been conducted on the usefulness of predicting pneumonia patient outcomes with parameters from electrical cardiometry.

Objective:

In the present study, we evaluated whether parameters measured by electrical cardiometry can predict clinical outcomes including mortality and length of hospital stay in patients with community-acquired pneumonia in the emergency department.

Methods:

Demographic, clinical and laboratory data were collected from enrolled patient. Electrical cardiometry monitoring was done with a portable electrical cardiometry device connected to the body surface sensor. The continuous data from electrical cardiometry were recorded, and parameters were stored on the electrical cardiometry device automatically and then the data were downloaded for further analysis.

Results:

Thoracic fluid content has shown to be significantly higher in the intensive care unit admission group and in the death group. Expired patients had higher value of thoracic fluid content at emergency department admission. From a receiver operating characteristics curve analysis, thoracic fluid content presented fair AUC values of 0.72 (95% confidence interval, 0.71–0.74) and 0.73 (0.62–0.82) for prediction of 28-day mortality and intensive care unit admission. Arterial partial pressure of oxygen (PaO2), the ratio of arterial partial pressure of oxygen to inspired oxygen fraction (PaO2/FiO2 ratio) also showed excellent AUC value for prediction of mortality and intensive care unit admission.

Conclusion:

Electrical cardiometry monitoring indicated new possibility to anticipate prognosis of community-acquired pneumonia patient. Increased thoracic fluid content value would relate worse outcome of the patient like mortality and intensive care unit admission. Electrical cardiometry monitoring allows real-time measurements of thoracic fluid content without restraining the patient or invasive catheters.

Phospholipid levels in blood during community-acquired pneumonia

Phospholipids, major constituents of bilayer cell membranes, are present in large amounts in pulmonary surfactant and play key roles in cell signaling. Here, we aim at finding clinically useful disease markers in community-acquired pneumonia (CAP) using comprehensive phospholipid profiling in blood and modeling of changes between sampling time points. Serum samples from 33 patients hospitalized with CAP were collected at admission, three hours after the start of intravenous antibiotics, Day 1 (at 12–24 h), Day 2 (at 36–48 h), and several weeks after recovery. A profile of 75 phospholipid species including quantification of the bioactive lysophosphatidylcholines (LPCs) was determined using liquid chromatography coupled to time-of-flight mass spectrometry. To control for possible enzymatic degradation of LPCs, serum autotaxin levels were examined. Twenty-two of the 33 patients with a clinical diagnosis of CAP received a laboratory-verified CAP diagnosis by microbial culture or microbial DNA detection by qPCR. All major phospholipid species, especially the LPCs, were pronouncedly decreased in the acute stage of illness. Total and individual LPC concentrations increased shortly after the initiation of antibiotic treatment, concentrations were at their lowest 3h after the initiation, and increased after Day 1. The total LPC concentration increased by a change ratio of 1.6–1.7 between acute illness and Day 2, and by a ratio of 3.7 between acute illness and full disease resolution. Autotaxin levels were low in acute illness and showed little changes over time, contradicting a hypothesis of enzymatic degradation causing the low levels of LPCs. In this sample of patients with CAP, the results demonstrate that LPC concentration changes in serum of patients with CAP closely mirrored the early transition from acute illness to recovery after the initiation of antibiotics. LPCs should be further explored as potential disease stage biomarkers in CAP and for their potential physiological role during recovery.

Ventilator-associated pneumonia by methicillin-susceptible Staphylococcus aureus: do minimum inhibitory concentrations to vancomycin and daptomycin matter?

The use of vancomycin minimum inhibitory concentration (MIC) as an outcome predictor in patients with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia has become an important topic for debate in the last few years. Given these previous results, we decided to investigate whether MICs to vancomycin or daptomycin had any effect on the evolution of patients with ventilator-associated pneumonia (VAP) due to MSSA. An observational, retrospective, multicenter study was conducted among patients with MSSA VAP. We analyzed the relationship between vancomycin and daptomycin MICs and early clinical response (72 h), 30-day mortality, intensive care unit (ICU) length of stay (LOS), and duration on mechanical ventilation. Univariate and multivariate analyses were performed. Sixty-six patients from 12 centers were included. Twenty-six patients (39%) had an infection due to MSSA strains with a vancomycin MIC ≥1.5 μg/mL. Daptomycin MIC was determined in 58 patients, of whom 17 (29%) had an MIC ≥1.0 μg/mL. Ten patients (15%) did not respond to first-line treatment. Only daptomycin MIC ≥1.0 μg/mL had a significant association [odds ratio (OR): 30.00; 95% confidence interval (CI): 2.91-60.41] with early treatment failure. The 30-day mortality was 12% (n = 8). Any variable was associated with mortality in the multivariate analysis. None of the variables studied were associated with ICU LOS or duration on mechanical ventilation. In patients with MSSA VAP, vancomycin MIC does not influence the response to antibiotic treatment or the 30-day mortality. Daptomycin MIC was directly related to early treatment failure.

Individualised antimicrobial dosing in critically ill patients undergoing continuous renal replacement therapy: focus on total drug clearance

Background

Continuous renal replacement therapy (CRRT) is common practice in critical care patients with acute renal failure.

Objectives

To evaluate the adequacy of antimicrobial doses calculated based on the total drug clearance and dose recommended by different guides in critically ill patients undergoing CRRT.

Methods

Retrospective observational study. Patients admitted to a critical care unit during May 2014 to May 2016 and subjected to CRRT were included. The recommended dose was established as the product of the usual dose of the drug by total drug clearance.

Results

177 antimicrobial agents, used in 64 patients were analysed; 45 (25.4%) antimicrobials were given in an insufficient dose (<20%) according to the theoretical calculation. Following the recommendations in the revised guidelines, between 10% and 20% of antimicrobials were given in insufficient doses. A higher success rate of treatment in those patients not receiving a low drug dosage was seen (35.2% vs 24.0%).

Conclusions

There is a great disparity between the antimicrobial dose prescribed, recommended and calculated based on drug clearance in critically ill patients undergoing CRRT.

Intensive care unit-acquired pneumonia due to Pseudomonas aeruginosa with and without multidrug resistance

OBJECTIVE

Pseudomonas aeruginosa often presents multi-drug resistance (MDR) in intensive care unit (ICU)-acquired pneumonia (ICUAP), possibly resulting in inappropriate empiric treatment and worse outcomes. We aimed to identify patients with ICUAP at risk for these pathogens in order to improve treatment selection and outcomes.

METHODS

We prospectively assessed 222 consecutive immunocompetent ICUAP patients confirmed microbiologically. We determined the characteristics, risk factors, systemic inflammatory response and outcomes of P. aeruginosa pneumonia (Pa-ICUAP), compared to other aetiologies. We also compared patients with MDR vs. non-MDR Pa-ICUAP.

RESULTS

Pseudomonas aeruginosa was the most frequent aetiology (64, 29%); 22 (34%) cases had MDR. Independent predictors for Pa-ICUAP were prior airway colonization by P. aeruginosa, previous antibiotic treatment, solid cancer and shock; alcohol abuse and pleural effusion were independently associated to lower risk for Pa-ICUAP. Chronic liver disease independently predicted MDR among Pa-ICUAP. The inflammatory biomarkers were similar between all groups. Patients with Pa-ICUAP had lower unadjusted 90-day survival (p = 0.049). However, the 90-day survival adjusted for confounding factors using a propensity score did not differ between all groups.

CONCLUSION

Pseudomonas aeruginosa remains the most frequent aetiology of ICUAP, with high prevalence of MDR. These risk factors should be taken into account to avoid inappropriate empiric antibiotics for Pa-ICUAP. Pseudomonas aeruginosa, regardless multidrug resistance, was not associated with different propensity-adjusted survival.

From starting mechanical ventilation to ventilator-associated pneumonia, choosing the right moment to start antibiotic treatment

Background

Ventilator-associated pneumonia (VAP) can have a clear onset or may be a result of the gradual appearance of symptoms and signs of VAP (gradual VAP). The aim of this paper is to describe the VAP development process with the intention of discriminating between those pneumonias with a clear beginning and those that are diagnosed after a period of maturation. In addition, we evaluate the effect of the starting time of antibiotic treatment in both situations.

Methods

Consecutive ventilated patients fulfilling VAP criteria were included. The patients were monitored for clinical, microbiological, and inflammatory signs. Patients with VAP were classified into two groups: (1) nongradual VAP (patients in whom all VAP criteria were detected for the first time on the day of diagnosis) and (2) gradual VAP (progressive appearance of signs and symptoms throughout the pre-VAP period [<96 h to >24 h before VAP diagnosis]).

Results

A total of 71 patients with VAP were identified, of whom 43 (61 %) had gradual VAP, most of whom (n = 38, 88 %) had late-onset VAP. Antibiotic treatment was given to 34 (79 %) patients with gradual VAP in the pre-VAP period, and empirical antibiotic treatment was appropriate in 22 patients (51 %). The patients with an appropriate empirical treatment had a higher percentage of early clinical response to treatment (68 % [n = 15] vs. 28 % [n = 7]; p = 0.009). An attempt was made to find a diagnostic test capable of identifying the infectious process underway, but clinical scales and biomarkers of inflammation helped us to achieve acceptable results.

Conclusions

Gradual emergence of VAP, mainly of late onset, is a common condition. Clinicians should be aware of this gradual onset of the infection to establish an early antibiotic treatment, even before the classic diagnostic criteria for VAP are applied.

Clinical Usefulness of Urinary Fatty Acid Binding Proteins in Assessing the Severity and Predicting Treatment Response of Pneumonia in Critically Ill Patients: A Cross-Sectional Study

To investigate the clinical relevance of urinary fatty acid binding proteins (FABPs), including intestinal-FABP, adipocyte-FABP, liver-FABP, and heart-FABP in pneumonia patients required admission to respiratory intensive care unit (RICU).Consecutive pneumonia patients who admitted to RICU from September 2013 to October 2014 were enrolled except for those with pneumonia for more than 24 h before admission to RICU. Pneumonia patients were further divided into with and without septic shock subgroups. Twelve patients without infection were enrolled to serve as control group. Urine samples were collected on days 1 and 7 after admission to RICU for measuring FABPs and inflammatory cytokines. Clinical and laboratory data were collected and compared between pneumonia and control groups, and between the pneumonia patients with and without septic shock.There were no significant differences in urinary levels of various FABPs and inflammatory cytokines measured on day 1 between control and pneumonia groups. Urinary values of intestine-FABP (P = 0.020), adipocyte-FABP (P = 0.005), heart-FABP (P = 0.025), and interleukin-6 (P = 0.019) were significantly higher and arterial oxygen tension/fraction of inspired oxygen (PaO2/FiO2, P/F) ratio (P = 0.024) was significantly lower in pneumonia patients with septic shock on day 1 than in those without septic shock. After multivariate analysis, adipocyte-FABP was the independent factor (P = 0.026). Urinary levels of FABPs measured on day 7 of pneumonia patients were significantly lower in the improved than in nonimproved groups (P = 0.030 for intestine-FABP, P = 0.003 for adipocyte-FABP, P = 0.010 for heart-FABP, and P = 0.008 for liver-FABP, respectively). After multivariate analysis, adipocyte-FABP was the independent factor (P = 0.023).For pneumonia patients required admission to RICU, urinary levels of adipocyte-FABP on days 1 and 7 after admission to RICU may be valuable in assessing the pneumonia severity and in predicting treatment response, respectively. Further studies with larger populations are needed to verify these issues.

Polymicrobial intensive care unit-acquired pneumonia: prevalence, microbiology and outcome

BACKGROUND

Microbial aetiology of intensive care unit (ICU)-acquired pneumonia (ICUAP) determines antibiotic treatment and outcomes. The impact of polymicrobial ICUAP is not extensively known. We therefore investigated the characteristics and outcomes of polymicrobial aetiology of ICUAP.

METHOD

Patients with ICUAP confirmed microbiologically were prospectively compared according to identification of 1 (monomicrobial) or more (polymicrobial) potentially-pathogenic microorganisms. Microbes usually considered as non-pathogenic were not considered for the etiologic diagnosis. We assessed clinical characteristics, microbiology, inflammatory biomarkers and outcome variables.

RESULTS

Among 441 consecutive patients with ICUAP, 256 (58%) had microbiologic confirmation, and 41 (16%) of them polymicrobial pneumonia. Methicillin-sensitive Staphylococcus aureus, Haemophilus influenzae, and several Enterobacteriaceae were more frequent in polymicrobial pneumonia. Multi-drug and extensive-drug resistance was similarly frequent in both groups. Compared with monomicrobial, patients with polymicrobial pneumonia had less frequently chronic heart disease (6, 15% vs. 71, 33%, p = 0.019), and more frequently pleural effusion (18, 50%, vs. 54, 25%, p = 0.008), without any other significant difference. Appropriate empiric antimicrobial treatment was similarly frequent in the monomicrobial (185, 86%) and the polymicrobial group (39, 95%), as were the initial response to the empiric treatment, length of stay and mortality. Systemic inflammatory response was similar comparing monomicrobial with polymicrobial ICUAP.

CONCLUSION

The aetiology of ICUAP confirmed microbiologically was polymicrobial in 16% cases. Pleural effusion and absence of chronic heart disease are associated with polymicrobial pneumonia. When empiric treatment is frequently appropriate, polymicrobial aetiology does not influence the outcome of ICUAP.

Tumor necrosis factor receptor 1 (TNFRI) for ventilator-associated pneumonia diagnosis by cytokine multiplex analysis

BACKGROUND

The diagnosis of ventilator-associated pneumonia (VAP) is challenging. An important aspect to improve outcome is early recognition of VAP and the initiation of the appropriate empirical treatment. We hypothesized that biological markers in plasma can rule out VAP at the moment of clinical suspicion and could rule in VAP before the diagnosis can be made clinically.

METHODS

In this prospective study, patients with VAP (n = 24, microbiology confirmed) were compared to controls (n = 19) with a similar duration of mechanical ventilation. Blood samples from the day of VAP diagnosis and 1 and 3 days before were analyzed with a multiplex array for markers of inflammation, coagulation, and apoptosis. The best biomarker combination was selected and the diagnostic accuracy was given by the area under the receiver operating characteristic curve (ROC-AUC).

RESULTS

TNF-receptor 1 (TNFRI) and granulocyte colony-stimulating factor (GCSF) were selected as optimal biomarkers at the day of VAP diagnosis, which resulted in a ROC-AUC of 0.96, with excellent sensitivity. Three days before the diagnosis TNFRI and plasminogen activator inhibitor-1 (PAI-1) levels in plasma predicted VAP with a ROC-AUC of 0.79. The slope of IL-10 and PAI-1 resulted in a ROC-AUC of 0.77. These biomarkers improved the classification of the clinical pulmonary infection score when combined.

CONCLUSIONS

Concentration of TNFRI and PAI-1 and the slope of PAI-1 and IL-10 may be used to predict the development of VAP as early as 3 days before the diagnosis made clinically. TNFRI and GCSF may be used to exclude VAP at the moment of clinical suspicion. Especially TNFRI seems to be a promising marker for the prediction and diagnosis of VAP.

Impact of Candida spp. isolation in the respiratory tract in patients with intensive care unit-acquired pneumonia

In immunocompetent patients with nosocomial pneumonia, the relationship between Candida spp. isolation in respiratory samples and outcomes or association with other pathogens is controversial. We therefore compared the characteristics and outcomes of patients with intensive care unit-acquired pneumonia (ICUAP), with or without Candida spp. isolation in the respiratory tract. In this prospective non-interventional study, we assessed 385 consecutive immunocompetent patients with ICUAP, according to the presence or absence of Candida spp. in lower respiratory tract samples. Candida spp. was isolated in at least one sample in 82 (21%) patients. Patients with Candida spp. had higher severity scores and organ dysfunction at admission and at onset of pneumonia. In multivariate analysis, previous surgery, diabetes mellitus and higher Simplified Acute Physiology Score II at ICU admission independently predicted isolation of Candida spp. There were no significant differences in the rate of specific aetiological pathogens, the systemic inflammatory response, and length of stay between patients with and without Candida spp. Mortality was also similar, even adjusted for potential confounders in propensity-adjusted multivariate analyses (adjusted hazard ratio 1.08, 95% CI 0.57-2.05, p 0.80 for 28-day mortality and adjusted hazard ratio 1.38, 95% CI 0.81-2.35, p 0.24 for 90-day mortality). Antifungal therapy was more frequently prescribed in patients with Candida spp. in respiratory samples but did not influence outcomes. Candida spp. airway isolation in patients with ICUAP is associated with more initial disease severity but does not influence outcomes in these patients, regardless of the use or not of antifungal therapy.

Impact of COPD in the outcome of ICU-acquired pneumonia with and without previous intubation

BACKGROUND

COPD seems related to poor outcome in patients with ventilator-associated pneumonia (VAP). However, many patients in the ICU with COPD do not require intubation but can also develop pneumonia in the ICU. We, therefore, compared the characteristics and outcomes of patients with ICU-acquired pneumonia (ICUAP) with and without underlying COPD.

METHODS

We prospectively assessed the characteristics, microbiology, systemic inflammatory response, and survival of 279 consecutive patients with ICUAP clustered according to underlying COPD or not. The primary end point was 90-day survival.

RESULTS

Seventy-one patients (25%) had COPD. The proportion of VAP was less frequent in patients with COPD: 30 (42%) compared with 126 (61%) in patients without COPD (P = .011). Patients with COPD were older; were more frequently men, smokers, and alcohol abusers; and more frequently had previous use of noninvasive ventilation. The rate of microbiologic diagnosis was similar between groups, with a higher rate of Aspergillus species and a lower rate of Enterobacteriaceae in patients with COPD. We found lower levels of IL-6 and IL-8 in patients with COPD without previous intubation. The 90-day mortality was higher in patients with COPD (40 [57%] vs 74 [37%] in patients without COPD, P = .003). Among others, COPD was independently associated with decreased 90-day survival in the overall population (adjusted hazard ratio, 1.94; 95% CI, 1.11-3.40; P = .020); this association was observed only in patients with VAP but not in those without previous intubation.

CONCLUSIONS

COPD was independently associated with decreased 90-day survival in patients with VAP but not in those without previous intubation.

Lung inflammatory pattern and antibiotic treatment in pneumonia

BACKGROUND

In community-acquired pneumonia host inflammatory response against the causative microorganism is necessary for infection resolution. However an excessive response can have deleterious effects. In addition to antimicrobial effects, macrolide antibiotics are known to possess immunomodulatory properties.

METHODS

A prospective study was performed on 52 admitted patients who developed an inadequate response after 72 hours of antibiotic treatment - non-responders community-acquired pneumonia - (blood and bronchoalveolar lavage), and two control groups: 1) community-acquired pneumonia control (blood) and 2) non-infection control (blood and bronchoalveolar lavage). Cytokine profiles (interleukin (IL)-6, IL-8, IL-10), tumour necrosis factor α and clinical outcomes were assessed.

RESULTS

Non-responders patients treated with macrolide containing regimens showed significantly lower levels of IL-6 and TNF-α in bronchoalveolar lavage fluid and lower IL-8 and IL-10 in blood than those patients treated with non-macrolide regimens. Clinical outcomes showed that patients treated with macrolide regimens required fewer days to reach clinical stability (p < 0.01) and shorter hospitalization periods (p < 0.01).

CONCLUSIONS

After 72 hours of antibiotic effect, patients who received macrolide containing regimens exhibited lower inflammatory cytokine levels in pulmonary and systemic compartments along with faster stabilization of infectious parameters.

Resistance patterns and outcomes in intensive care unit (ICU)-acquired pneumonia. Validation of European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC) classification of multidrug resistant organisms

INTRODUCTION

Bacterial resistance has become a major public health problem.

OBJECTIVE

To validate the definition of multidrug-resistant organisms (MDRO) based on the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC) classification.

MATERIAL

Prospective, observational study in six medical and surgical Intensive-Care-Units (ICU) of a University hospital.

RESULTS

Three-hundred-and-forty-three patients with ICU-acquired pneumonia (ICUAP) were prospectively enrolled, 140 patients had no microbiological confirmation (41%), 82 patients (24%) developed ICUAP for non-MDRO, whereas 121 (35%) were MDROs. Non-MDRO, MDRO and no microbiological confirmation patients did not present either a significant different previous antibiotic use (p 0.18) or previous hospital admission (p 0.17). Appropriate antibiotic therapy was associated with better ICU survival (105 [92.9%] vs. 74 [82.2%]; p = 0.03). An adjusted multivariate regression logistic analysis identified that only MDRO had a higher ICU-mortality than non-MDRO and no microbiological confirmation patients (OR 2.89; p < 0.05; 95% CI for Exp [β]. 1.02-8.21); Patients with MDRO ICUAP remained in ICU for a longer period than MDRO and no microbiological confirmation respectively (p < 0.01) however no microbiological confirmation patients had more often antibiotic consumption than culture positive ones.

CONCLUSIONS

Patients who developed ICUAP due to MDRO showed a higher ICU-mortality than non-MDRO ones and use of ICU resources. No microbiological confirmation patients had more often antibiotic consumption than culture positive patients. Risk factors for MDRO may be important for the selection of initial antimicrobial therapy, in addition to local epidemiology.

Community-acquired pneumonia: identification and evaluation of nonresponders

Community acquired pneumonia (CAP) is a relevant public health problem, constituting an important cause of morbidity and mortality. It accounts for a significant number of adult hospital admissions and a large number of those patients ultimately die, especially the population who needed mechanical ventilation or vasopressor support. Thus, early identification of CAP patients and its rapid and appropriate treatment are important features with impact on hospital resource consumption and overall mortality. Although CAP diagnosis may sometimes be straightforward, the diagnostic criteria commonly used are highly sensitive but largely unspecific. Biomarkers and microbiological documentation may be useful but have important limitations. Evaluation of clinical response is also critical especially to identify patients who fail to respond to initial treatment since these patients have a high risk of in-hospital death. However, the criteria of definition of non-response in CAP are largely empirical and frequently markedly diverse between different studies. In this review, we aim to identify criteria defining nonresponse in CAP and the pitfalls associated with this diagnosis. We also aim to overview the main causes of treatment failure especially in severe CAP and the possible strategies to identify and reassess non-responders trying to change the dismal prognosis associated with this condition.

Development of a novel preclinical model of pneumococcal pneumonia in nonhuman primates

Pneumococcal pneumonia is a leading cause of bacterial infection and death worldwide. Current diagnostic tests for detecting Streptococcus pneumoniae can be unreliable and can mislead clinical decision-making and treatment. To address this concern, we developed a preclinical model of pneumococcal pneumonia in nonhuman primates useful for identifying novel biomarkers, diagnostic tests, and therapies for human S. pneumoniae infection. Adult colony-bred baboons (n = 15) were infected with escalating doses of S. pneumoniae (Serotype 19A-7). We characterized the pathophysiological and serological profiles of healthy and infected animals over 7 days. Pneumonia was prospectively defined by the presence of three criteria: (1) change in white blood cell count, (2) isolation of S. pneumoniae from bronchoalveolar lavage fluid (BALF) or blood, and (3) concurrent signs/symptoms of infection. Animals given 10(9) CFU consistently met our definition and developed a phenotype of tachypnea, tachycardia, fever, hypoxemia, and radiographic lobar infiltrates at 48 hours. BALF and plasma cytokines, including granulocyte colony-stimulating factor, IL-6, IL-10, and IL-1ra, peaked at 24 to 48 hours. At necropsy, there was lobar consolidation with frequent pleural involvement. Lung histopathology showed alveolar edema and macrophage influx in areas of organizing pneumonia. Hierarchical clustering of peripheral blood RNA data at 48 hours correctly identified animals with and without pneumonia. Dose-dependent inoculation of baboons with S. pneumoniae produces a host response ranging from spontaneous clearance (10(6) CFU) to severe pneumonia (10(9) CFU). Selected BALF and plasma cytokine levels and RNA profiles were associated with severe pneumonia and may provide clinically useful parameters after validation.

Assessment of severity of ICU-acquired pneumonia and association with etiology

OBJECTIVES

We evaluated the association between severity of illness and microbial etiology of ICU-acquired pneumonia to define if severity should be used to guide empiric antibiotic choices.

DESIGN

Prospective observational study.

SETTING

ICUs of a university hospital.

PATIENTS

Three hundredy forty-three consecutive patients with ICU-acquired pneumonia clustered, according to the presence of multidrug resistant pathogens.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred eight patients had ventilator-associated pneumonia and 135 had nonventilator ICU-acquired pneumonia. We determined etiology in 217 patients (63%). The most frequent pathogens were Pseudomonas aeruginosa, Enterobacteriaceae, and methicillin-sensitive and methicillin-resistant Staphylococcus aureus. Fifty-eight patients (17%) had a multidrug-resistant causative agent. Except for a longer ICU stay and a higher rate of microbial persistence at the end of the treatment in the multidrug-resistant group, no differences were found in clinical and inflammatory characteristics, severity criteria, and mortality or survival between patients with and without multidrug-resistant pathogens, even after adjusting for potential confounders. Patients with higher severity scores (Acute Physiology and Chronic Health Evaluation II and Sepsis-related Organ Failure Assessment) and septic shock at onset of pneumonia had significantly lower 28- and 90-day survival and higher systemic inflammatory response. The results were similar when only patients with microbial diagnosis were considered, as well as when stratified into ventilator-associated pneumonia and nonventilator ICU-acquired pneumonia.

CONCLUSIONS

In patients with ICU-acquired pneumonia, severity of illness seems not to affect etiology. Risk factors for multidrug resistant, but not severity of illness, should be taken into account in selecting empiric antimicrobial treatment.

Incidence of nosocomial pneumonia and risk of recurrence after antimicrobial therapy in critically ill lung and heart-lung transplant patients

Little is known about the resolution of symptoms of nosocomial pneumonia (NosoP) after lung and heart-lung transplantation. The aim of this study was to describe the clinical response to antimicrobial therapy in (ICU) patients with NosoP after lung or heart-lung transplantation. Between January 2008 and August 2010, 79 lung or heart-lung transplantations patients were prospectively studied. NosoPwas confirmed by quantitative cultures of bronchoalveolar lavage or endotracheal aspirates. Clinical variables, sequential organ failure assessment (SOFA) score, and radiologic score were recorded from start of therapy until day 9. Thirty-five patients (44%) experienced 64 episodes of NosoP in ICU. Fourteen patients (40%) had NosoP recurrence. Most frequently isolated organisms were Enterobacteriaceae (30%), Pseudomonas aeruginosa (25%), and Staphylococcus aureus (20%). Sequential organ failure assessment (SOFA) score improved significantly at day 6 and C-reactive protein level at day 9. SOFA and radiologic scores differed significantly between patients with and without NosoP recurrence at day 3 and 9. The ICU mortality rate did not differ between patients with and without NosoP recurrence, and free of NosoP (14.3%, 9.5%, 11.4%, respectively) (p = 0.91). Severities of illness and lung injury were the two major risk factors for NosoP recurrence. Occurrence of NosoP has no impact on ICU mortality.

ICU-acquired pneumonia with or without etiologic diagnosis: a comparison of outcomes

OBJECTIVES

The impact of ICU-acquired pneumonia without etiologic diagnosis on patients' outcomes is largely unknown. We compared the clinical characteristics, inflammatory response, and outcomes between patients with and without microbiologically confirmed ICU-acquired pneumonia.

DESIGN

Prospective observational study.

SETTING

ICUs of a university teaching hospital.

PATIENTS

We prospectively collected 270 consecutive patients with ICU-acquired pneumonia. Patients were clustered according to positive or negative microbiologic results.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We compared the characteristics and outcomes between both groups. Negative microbiology was found in 82 patients (30%). Both groups had similar baseline severity scores. Patients with negative microbiology presented more frequently chronic renal failure (15 [18%] vs 11 [6%]; p=0.003), chronic heart disorders (35 [43%] vs 55 [29%]; p=0.044), less frequently previous intubation (44 [54%] vs 135 [72%]; p=0.006), more severe hypoxemia (PaO2/FIO2: 165±73 mm Hg vs 199±79 mm Hg; p=0.001), and shorter ICU stay before the onset of pneumonia (5±5 days vs 7±9 days; p=0.001) compared with patients with positive microbiology. The systemic inflammatory response was similar between both groups. Negative microbiology resulted in less changes of empiric treatment (33 [40%] vs 112 [60%]; p=0.005) and shorter total duration of antimicrobials (13±6 days vs 17±12 days; p=0.006) than positive microbiology. Following adjustment for potential confounders, patients with positive microbiology had higher hospital mortality (adjusted odds ratio 2.96, 95% confidence interval 1.24-7.04, p=0.014) and lower 90-day survival (adjusted hazard ratio 0.50, 95% confidence interval 0.27-0.94, p=0.031), with a nonsignificant lower 28-day survival.

CONCLUSIONS

Although the possible influence of previous intubation in mortality of both groups is not completely discarded, negative microbiologic findings in clinically suspected ICU-acquired pneumonia are associated with less frequent previous intubation, shorter duration of antimicrobial treatment, and better survival. Future studies should corroborate the presence of pneumonia in patients with suspected ICU-acquired pneumonia and negative microbiology.

Validation of predictors of adverse outcomes in hospital-acquired pneumonia in the ICU

OBJECTIVE

To validate a set of predictors of adverse outcomes in patients with ICU-acquired pneumonia in relation to clinically relevant assessment at 28 days.

DESIGN

Prospective, observational study.

SETTING

Six medical and surgical ICUs of a university hospital.

PATIENTS

Three hundred thirty-five patients with ICU-acquired pneumonia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Development of predictors of adverse outcomes was defined when at least one of the following criteria was present at an evaluation made 72-96 hours after starting treatment: no improvement of PaO2/FIO2, need for intubation due to pneumonia, persistence of fever or hypothermia with purulent respiratory secretions, greater than or equal to 50% increase in radiographic infiltrates, or occurrence of septic shock or multiple organ dysfunction syndrome. We also assessed the inflammatory response by different serum biomarkers. The presence of predictors of adverse outcomes was related to mortality and ventilator-free days at day 28. Sequential Organ Failure Assessment score was evaluated and related to mortality at day 28.One hundred eighty-four (55%) patients had at least one predictor of adverse outcomes. The 28-day mortality was higher for those with versus those without predictors of adverse outcomes (45% vs 19%, p<0.001), and ventilator-free days were lower (median [interquartile range], 0 [0-17] vs 22 [0-28]) for patients with versus patients without predictors of adverse outcomes (p<0.001). The lack of improvement of PaO2/FIO2 and lack of improvement in Sequential Organ Failure Assessment score from day 1 to day 5 were independently associated with 28-day mortality and fewer ventilator-free days. The marginal structural analysis showed an odds ratio of death 2.042 (95% CI, 1.01-4.13; p=0.047) in patients with predictors of adverse outcomes. Patients with predictors of adverse outcomes had higher serum inflammatory response accordingly to biomarkers evaluated.

CONCLUSIONS

The presence of any predictors of adverse outcomes was associated with mortality and decreased ventilator-free days at day 28. The lack of improvement in the PaO2/FIO2 and Sequential Organ Failure Assessment score was independently associated with mortality in the multivariate analysis.

Impact of chronic liver disease in intensive care unit acquired pneumonia: a prospective study

PURPOSE

To assess the impact of chronic liver disease (CLD) on ICU-acquired pneumonia.

METHODS

This was a prospective, observational study of the characteristics, microbiology, and outcomes of 343 consecutive patients with ICU-acquired pneumonia clustered according to the presence of CLD.

RESULTS

Sixty-seven (20%) patients had CLD (67% had liver cirrhosis, LC), MELD score 26 ± 9, 20% Child-Pugh class C). They presented higher severity scores than patients without CLD both on admission to the ICU (APACHE II, LC 19 ± 6 vs. other CLD 18 ± 6 vs. no CLD 16 ± 6; p < 0.001; SOFA, 10 ± 3 vs. 8 ± 4 vs. 7 ± 3; p < 0.001) and at onset of pneumonia (APACHE II, 19 ± 6 vs. 17 ± 6 vs. 16 ± 5; p = 0.001; SOFA, 11 ± 4 vs. 9 ± 4 vs. 7 ± 3; p < 0.001). Levels of CRP were lower in patients with LC than in the other two groups (day 1, 6.5 [2.5-11.5] vs. 13 [6-23] vs. 15.5 [8-24], p < 0.001, day 3, 6 [3-12] vs. 16 [9-21] vs. 11 [5-20], p = 0.001); all the other biomarkers were higher in LC and other CLD patients. LC patients had higher 28- and 90-day mortality (63 vs. 28%, p < 0.001; 72 vs. 38%, p < 0.001, respectively) than non-CLD patients. Presence of LC was independently associated with decreased 28- and 90-day survival (95% confidence interval [CI], 1.982-17.250; p = 0.001; 95% confidence interval [CI], 2.915-20.699, p = 0.001, respectively).

CONCLUSIONS

In critically ill patients with ICU-acquired pneumonia, CLD is associated with a more severe clinical presentation and poor clinical outcomes. Moreover, LC is independently associated with 28- and 90-day mortality. The results of this study are important for future trials focused on mortality.

Efficacy of methylprednisolone in children with severe community acquired pneumonia

BACKGROUND

The clinical value of adjuvant corticosteroid treatment in community-acquired pneumonia (CAP) seemed to be controversial in adults, and even less data are available on the use of corticosteroids in children with CAP.

MATERIALS AND METHODS

In this study, we investigated the efficacy of a 5-day adjuvant methylprednisolone therapy to imipenem in 29 children with severe CAP. In parallel, 30 subjects with the same disease were treated with imipenem and placebo, and the two study groups were compared based on the different parameters of the primary and secondary end points. The primary end points were the duration of fever, the levels of white blood cells (WBC) and high sensitive C-reactive protein (hsCRP). Secondary end points were the length of hospital stay, and the number of severe complications with or without surgical interventions.

RESULTS

The additive methylprednisolone treatment significantly reduced the duration of fever with 2.5 days, the WBC counts (P = 0.014), the hsCRP levels showing a 48.7% decrease, and the length of hospital stay with 5.2 days versus the placebo group. Moreover, patients treated on imipenem alone had twice more complications and four times more invasive interventions compared to those on the combined therapy.

CONCLUSIONS

The 5-day methylprednisolone therapy with imipenem was found effective in children having severe CAP. However, trials with larger cohorts are needed to study further beneficial effects of corticosteroids in children with CAP.

Association between systemic corticosteroids and outcomes of intensive care unit-acquired pneumonia

OBJECTIVE

The use of corticosteroids is frequent in critically-ill patients. However, little information is available on their effects in patients with intensive care unit-acquired pneumonia. We assessed patients' characteristics, microbial etiology, inflammatory response, and outcomes of previous corticosteroid use in patients with intensive care unit-acquired pneumonia.

DESIGN

Prospective observational study.

SETTING

Intensive care units of a university teaching hospital.

PATIENTS

Three hundred sixteen patients with intensive care unit-acquired pneumonia. Patients were divided according to previous systemic steroid use at onset of pneumonia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Survival at 28 days was analyzed using Cox regression, with adjustment for the propensity for receiving steroid therapy. One hundred twenty-five (40%) patients were receiving steroids at onset of pneumonia. Despite similar baseline clinical severity, steroid treatment was associated with decreased 28-day survival (adjusted hazard ratio for propensity score and mortality predictors 2.503; 95% confidence interval 1.176-5.330; p = .017) and decreased systemic inflammatory response. In post hoc analyses, steroid treatment had an impact on survival in patients with nonventilator intensive care unit-acquired pneumonia, those with lower baseline severity and organ dysfunction, and those without etiologic diagnosis or bacteremia. The cumulative dosage of corticosteroids had no significant effect on the risk of death, but bacterial burden upon diagnosis was higher in patients receiving steroid therapy.

CONCLUSIONS

In critically-ill patients, systemic corticosteroids should be used very cautiously because this treatment is strongly associated with increased risk of death in patients with intensive care unit-acquired pneumonia, particularly in the absence of established indications and in patients with lower baseline severity. Decreased inflammatory response may result in delayed clinical suspicion of intensive care unit-acquired pneumonia and higher bacterial count.

Implications of endotracheal tube biofilm in ventilator-associated pneumonia response: a state of concept

INTRODUCTION

Biofilm in endotracheal tubes (ETT) of ventilated patients has been suggested to play a role in the development of ventilator-associated pneumonia (VAP). Our purpose was to analyze the formation of ETT biofilm and its implication in the response and relapse of VAP.

METHODS

We performed a prospective, observational study in a medical intensive care unit. Patients mechanically ventilated for more than 24 hours were consecutively included. We obtained surveillance endotracheal aspirates (ETA) twice weekly and, at extubation, ETTs were processed for microbiological assessment and scanning electron microscopy.

RESULTS

Eighty-seven percent of the patients were colonized based on ETA cultures. Biofilm was found in 95% of the ETTs. In 56% of the cases, the same microorganism grew in ETA and biofilm. In both samples the most frequent bacteria isolated were Acinetobacter baumannii and Pseudomonas aeruginosa. Nineteen percent of the patients developed VAP (N = 14), and etiology was predicted by ETA in 100% of the cases. Despite appropriate antibiotic treatment, bacteria involved in VAP were found in biofilm (50%). In this situation, microbial persistence and impaired response to treatment (treatment failure and relapse) were more frequent (100% vs 29%, P = 0.021; 57% vs 14%, P = 0.133).

CONCLUSIONS

Airway bacterial colonization and biofilm formation on ETTs are early and frequent events in ventilated patients. There is microbiological continuity between airway colonization, biofilm formation and VAP development. Biofilm stands as a pathogenic mechanism for microbial persistence, and impaired response to treatment in VAP.

Nosocomial pneumonia in the intensive care unit acquired by mechanically ventilated versus nonventilated patients

RATIONALE

Most current information on hospital-acquired pneumonia (HAP) is extrapolated from patients with ventilator-associated pneumonia (VAP). No studies have evaluated HAP in the intensive care unit (ICU) in nonventilated patients.

OBJECTIVES

To compare pneumonia acquired in the ICU by mechanically ventilated versus nonventilated patients.

METHODS

We prospectively collected 315 episodes of ICU-acquired pneumonia. We compared clinical and microbiologic characteristics of patients with VAP (n = 164; 52%) and nonventilator ICU-acquired pneumonia (NV-ICUAP; n = 151; 48%). Among NV-ICUAP patients, 79 (52%) needed subsequent intubation.

MEASUREMENTS AND MAIN RESULTS

Compared with NV-ICUAP, patients with VAP were more severe (APACHE-II 17 ± 6 vs. 15 ± 5; P < 0.001) and pneumonia occurred later in the ICU (8 ± 8 vs. 5 ± 6 d; P < 0.001). Etiologic diagnosis (117, 71% vs. 64, 42%; P < 0.001), nonfermenting (28% vs. 15%; P = 0.009) and enteric gram-negative bacilli (26% vs. 13%; P = 0.006), and methicillin-sensitive Staphylococcus aureus (14% vs. 6%; P = 0.031) were more frequent in VAP, likely caused by more patients with lower respiratory tract samples cultured (100% vs. 84%; P < 0.001). However, in patients with defined etiology only, the proportion of pathogens was similar between groups, except for a higher proportion of Streptococcus pneumoniae in NV-ICUAP (P = 0.045). The hospital mortality also was similar.

CONCLUSIONS

Despite a lower proportion of pathogens in NV-ICUAP compared with VAP, the type of isolates and outcomes are similar regardless of whether pneumonia is acquired or not during ventilation, indicating they may depend on patients' underlying severity rather than previous intubation. With the diagnostic techniques currently recommended by guidelines, both types of patients might receive similar empiric antibiotic treatment.