Attributable Mortality of Ventilator-associated Pneumonia. Replicating Findings, Revisiting Methods

Risk factors and outcomes of ventilator-associated pneumonia in patients with traumatic brain injury: A systematic review and meta-analysis

BACKGROUND

Ventilator-associated pneumonia (VAP) is a common complication in traumatic brain injury (TBI) patients, which increases morbidity and negatively affects outcomes. Risk factors and outcomes in these patients remain controversial. The aim of the present study is to explore the risk factors and clinical outcomes of patients with VAP and TBI.

METHODS

Two researchers conducted independent systematic literature searches of Pubmed, Cochrane Database, Scopus, Medline Ovid, Science Direct databases, published from inception to January 2024. The Newcastle-Ottawa scale was used to assess study quality. A meta-analysis was performed using a random-effects model when heterogeneity I2 > 50 % and a fixed-effects model when I2 < 50 %; in addition, a subgroup analysis was performed to explore VAP risk factors, and publication bias was assessed with the funnel plot and Begg's and Egger's tests. All results were considered statistically significant when p < 0.05. The certainty of the evidence was evaluated using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) methodology.

RESULTS

Twelve studies were included in the meta-analysis with a total of 2883 patients. Male gender [OR 1.58 (95 % CI 1.23, 2.02) p < 0.05 I2 0 %] and abbreviated injury scale (head: H-AIS) [≥ 3 OR 2.79 (95 % CI 1.58, 4.93) p < 0.05 I2 0 %] increased the risk of VAP. After subgroup analysis, blood transfusion on admission [OR 1.97 (95 % CI 1.16-3.35) p ≤0.05 I2 5 %] and barbiturate infusion [OR 3.55 (95 % CI 2.01-6.30) p ≤0.05 I2 0 %] became risk factors. Prophylactic antibiotic use [OR 0.67 (95 % CI 0.51-0.88) p ≤0.05 I2 0 %] and younger age MD -3.29 (95 % CI -5.18, -1.40) p ≤0.05 I2 41 %] emerged as significant protective factors. In VAP patients ICU stay [MD 7.02 (95 % CI 6.05-7.99) p ≤0.05 I2 37 %], duration of mechanical ventilation [MD 5.79 (95 % CI 4.40, 7.18) p ≤0.05 I2 79 %] and hospital stay [MD 11.88 (95 % CI 8.71-15.05) p ≤0.05 I2 0 %] were significantly increased. The certainty of the evidence was moderate-high for the outcomes studied.

CONCLUSIONS

Male gender, H-AIS ≥ 3, blood transfusion on admission, and barbiturate infusion were risk factors for VAP. In patients with VAP, ICU stay, duration of mechanical ventilation, hospital stay were significantly increased.

Causes and attributable fraction of death from ARDS in inflammatory phenotypes of sepsis

BACKGROUND

Hypoinflammatory and hyperinflammatory phenotypes have been identified in both Acute Respiratory Distress Syndrome (ARDS) and sepsis. Attributable mortality of ARDS in each phenotype of sepsis is yet to be determined. We aimed to estimate the population attributable fraction of death from ARDS (PAFARDS) in hypoinflammatory and hyperinflammatory sepsis, and to determine the primary cause of death within each phenotype.

METHODS

We studied 1737 patients with sepsis from two prospective cohorts. Patients were previously assigned to the hyperinflammatory or hypoinflammatory phenotype using latent class analysis. The PAFARDS in patients with sepsis was estimated separately in the hypo and hyperinflammatory phenotypes. Organ dysfunction, severe comorbidities, and withdrawal of life support were abstracted from the medical record in a subset of patients from the EARLI cohort who died (n = 130/179). Primary cause of death was defined as the organ system that most directly contributed to death or withdrawal of life support.

RESULTS

The PAFARDS was 19% (95%CI 10,28%) in hypoinflammatory sepsis and, 14% (95%CI 6,20%) in hyperinflammatory sepsis. Cause of death differed between the two phenotypes (p < 0.001). Respiratory failure was the most common cause of death in hypoinflammatory sepsis, whereas circulatory shock was the most common cause in hyperinflammatory sepsis. Death with severe underlying comorbidities was more frequent in hypoinflammatory sepsis (81% vs. 67%, p = 0.004).

CONCLUSIONS

The PAFARDS is modest in both phenotypes whereas primary cause of death among patients with sepsis differed substantially by phenotype. This study identifies challenges in powering future clinical trials to detect changes in mortality outcomes among patients with sepsis and ARDS.

Association Between Daily Toothbrushing and Hospital-Acquired Pneumonia: A Systematic Review and Meta-Analysis

Importance

Hospital-acquired pneumonia (HAP) is the most common and morbid health care-associated infection, but limited data on effective prevention strategies are available.

Objective

To determine whether daily toothbrushing is associated with lower rates of HAP and other patient-relevant outcomes.

Data Sources

A search of PubMed, Embase, Cumulative Index to Nursing and Allied Health, Cochrane Central Register of Controlled Trials, Web of Science, Scopus, and 3 trial registries was performed from inception through March 9, 2023.

Study Selection

Randomized clinical trials of hospitalized adults comparing daily oral care with toothbrushing vs regimens without toothbrushing.

Data Extraction and Synthesis

Data extraction and risk of bias assessments were performed in duplicate. Meta-analysis was performed using random-effects models.

Main Outcomes and Measures

The primary outcome of this systematic review and meta-analysis was HAP. Secondary outcomes included hospital and intensive care unit (ICU) mortality, duration of mechanical ventilation, ICU and hospital lengths of stay, and use of antibiotics. Subgroups included patients who received invasive mechanical ventilation vs those who did not, toothbrushing twice daily vs more frequently, toothbrushing provided by dental professionals vs general nursing staff, electric vs manual toothbrushing, and studies at low vs high risk of bias.

Results

A total of 15 trials met inclusion criteria, including 10 742 patients (2033 in the ICU and 8709 in non-ICU departments; effective population size was 2786 after shrinking the population to account for 1 cluster randomized trial in non-ICU patients). Toothbrushing was associated with significantly lower risk for HAP (risk ratio [RR], 0.67 [95% CI, 0.56-0.81]) and ICU mortality (RR, 0.81 [95% CI, 0.69-0.95]). Reduction in pneumonia incidence was significant for patients receiving invasive mechanical ventilation (RR, 0.68 [95% CI, 0.57-0.82) but not for patients who were not receiving invasive mechanical ventilation (RR, 0.32 [95% CI, 0.05-2.02]). Toothbrushing for patients in the ICU was associated with fewer days of mechanical ventilation (mean difference, -1.24 [95% CI, -2.42 to -0.06] days) and a shorter ICU length of stay (mean difference, -1.78 [95% CI, -2.85 to -0.70] days). Brushing twice a day vs more frequent intervals was associated with similar effect estimates. Results were consistent in a sensitivity analysis restricted to 7 studies at low risk of bias (1367 patients). Non-ICU hospital length of stay and use of antibiotics were not associated with toothbrushing.

Conclusions

The findings of this systematic review and meta-analysis suggest that daily toothbrushing may be associated with significantly lower rates of HAP, particularly in patients receiving mechanical ventilation, lower rates of ICU mortality, shorter duration of mechanical ventilation, and shorter ICU length of stay. Policies and programs encouraging more widespread and consistent toothbrushing are warranted.

Short-course versus prolonged-course antibiotic regimens for ventilator-associated pneumonia: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Current guidelines recommend short-duration antibiotic therapy for non-fermenting gram-negative bacilli (NF-GNB) ventilator-associated pneumonia (VAP) which may be associated with a higher recurrence of pneumonia. In this meta-analysis, we aimed to compare short- versus prolonged-course antibiotic regimens for VAP.

METHODS

We searched several databases for randomized controlled trials (RCTs) that compared the effectiveness of a short- versus long-course of antibiotic treatment in patients with VAP. Data analysis was performed using RevMan 5.4.

RESULTS

Our pooled analysis consisted of six RCTs. For 28-day mortality, no significant difference was found between the prolonged course and the short course. Administration of a short course of antibiotics increased the risk of recurrence of pneumonia in patients with VAP due to NF-GNB (RR 1.73; 95% CI: 1.17-2.54). Secondary outcomes, such as clinical resolution, duration of ICU stay, and duration of mechanical ventilation, revealed no significant difference between the two regimens. The quality of evidence was low for most outcomes.

CONCLUSIONS

Low-quality evidence suggests that a short course of antibiotics is associated with a higher recurrence of pneumonia in NF-GNB VAP with no difference in mortality as compared to a prolonged course. For definitive conclusions, large-scale and blinded RCTs are required.

Antimicrobial Resistance in Ventilator-Associated Pneumonia: Predictive Microbiology and Evidence-Based Therapy

Ventilator-associated pneumonia (VAP) is a serious intensive care unit (ICU)-related infection in mechanically ventilated patients that is frequent, as more than half of antibiotics prescriptions in ICU are due to VAP. Various risk factors and diagnostic criteria for VAP have been referred to in different settings. The estimated attributable mortality of VAP can go up to 50%, which is higher in cases of antimicrobial-resistant VAP. When the diagnosis of pneumonia in a mechanically ventilated patient is made, initiation of effective antimicrobial therapy must be prompt. Microbiological diagnosis of VAP is required to optimize timely therapy since effective early treatment is fundamental for better outcomes, with controversy continuing regarding optimal sampling and testing. Understanding the role of antimicrobial resistance in the context of VAP is crucial in the era of continuously evolving antimicrobial-resistant clones that represent an urgent threat to global health. This review is focused on the risk factors for antimicrobial resistance in adult VAP and its novel microbiological tools. It aims to summarize the current evidence-based knowledge about the mechanisms of resistance in VAP caused by multidrug-resistant bacteria in clinical settings with focus on Gram-negative pathogens. It highlights the evidence-based antimicrobial management and prevention of drug-resistant VAP. It also addresses emerging concepts related to predictive microbiology in VAP and sheds lights on VAP in the context of coronavirus disease 2019 (COVID-19).

Ventilator-Associated Pneumonia in Immunosuppressed Patients

Immunocompromised patients-including patients with cancer, hematological malignancies, solid organ transplants and individuals receiving immunosuppressive therapies for autoimmune diseases-account for an increasing proportion of critically-ill patients. While their prognosis has improved markedly in the last decades, they remain at increased risk of healthcare- and intensive care unit (ICU)-acquired infections. The most frequent of these are ventilator-associated lower respiratory tract infections (VA-LTRI), which include ventilator-associated pneumonia (VAP) and tracheobronchitis (VAT). Recent studies have shed light on some of the specific features of VAP and VAT in immunocompromised patients, which is the subject of this narrative review. Contrary to previous belief, the incidence of VAP and VAT might actually be lower in immunocompromised than non-immunocompromised patients. Further, the relationship between immunosuppression and the incidence of VAP and VAT related to multidrug-resistant (MDR) bacteria has also been challenged recently. Etiological diagnosis is essential to select the most appropriate treatment, and the role of invasive sampling, specifically bronchoscopy with bronchoalveolar lavage, as well as new molecular syndromic diagnostic tools will be discussed. While bacteria-especially gram negative bacteria-are the most commonly isolated pathogens in VAP and VAT, several opportunistic pathogens are a special concern among immunocompromised patients, and must be included in the diagnostic workup. Finally, the impact of immunosuppression on VAP and VAT outcomes will be examined in view of recent papers using improved statistical methodologies and treatment options-more specifically empirical antibiotic regimens-will be discussed in light of recent findings on the epidemiology of MDR bacteria in this population.

Impact of Rose Water Mouthwash on Prevention of Ventilator-Associated Pneumonia in Intensive Care Unit: A Randomized Controlled Trial

Background

Preventing Ventilator- Associated Pneumonia (VAP) is an important strategy to increase the quality of provided care for patients under mechanical ventilation. Rose water is the main product of Rosa damascena which is a popular medicinal plant and has been widely used in alternative medicine. It has antibacterial activity against gram-negative and gram-positive bacteria which can potentially cause VAP.

Materials and Methods

This study was a randomized, controlled, single-center trial. 88 patients in a 21-bed surgical Intensive Care Unit (ICU) who were under mechanical ventilation met the inclusion criteria, and 80 patients fulfilled the study. Based on receiving either rose water and chlorhexidine solution or chlorhexidine solution alone, the patients were divided into two groups of control and intervention. The incidence of VAP up to 14 days was the primary outcome. Duration of mechanical ventilation, the ICU length of stay, and mortality in ICU were the secondary outcomes.

Results

There was no significant difference in demographic data, the incidence of VAP, the incidence of late-onset VAP, mechanical ventilation days, length of the ICU stay, and mortality between the two groups. However, the incidence of early-onset VAP in the intervention group was significantly lower than in the control group (p= 0.021).

Conclusion

Rose water mouthwash significantly reduced the risk of early-onset VAP without any effect on late-onset VAP.

The population-attributable fraction for time-to-event data

Background

Even though the population-attributable fraction (PAF) is a well-established metric, it is often incorrectly estimated or interpreted not only in clinical application, but also in statistical research articles. The risk of bias is especially high in more complex time-to-event data settings.

Methods

We explain how the PAF can be defined, identified and estimated in time-to-event settings with competing risks and time-dependent exposures. By using multi-state methodology and inverse probability weighting, we demonstrate how to reduce or completely avoid severe types of biases including competing risks bias, immortal time bias and confounding due to both baseline and time-varying patient characteristics.

Results

The method is exemplarily applied to a real data set. Moreover, we estimate the number of deaths that were attributable to ventilator-associated pneumonia in France in the year 2016. The example demonstrates how, under certain simplifying assumptions, PAF estimates can be extrapolated to a target population of interest.

Conclusions

Defining and estimating the PAF in advanced time-to-event settings within a framework that unifies causal and multi-state modelling enables to tackle common sources of bias and allows straightforward implementation with standard software packages.

Time to Look for Another Infectious Source? White Blood Cell Trends during Ventilator-Associated Pneumonia

Background: Ventilator-associated pneumonia (VAP) continues to plague patients in intensive care units (ICUs) throughout the world. Persistent leukocytosis despite antibiotic treatment for VAP can have many etiologies including normal inflammatory response, inadequate VAP antimicrobial therapy, and the presence of additional infectious diagnoses. Hypothesis: Surgical patients with VAP and a second infectious source have a different white blood cell count (WBC) trend than patients with VAP alone. Patients and Methods: Retrospective, single-center study of surgical ICU patients diagnosed with VAP (>10⁴ CFU/mL on semi-quantitative culture) between January 2019 and June 2020. Chart review identified additional infections diagnosed during VAP treatment. White blood cell count values were compared between patients treated for VAP alone (VAP-alone) and those with additional infections (VAP-plus) using a Wilcoxon test. Univariable analysis compared admission type, surgeries, and steroid use between cohorts. Results: Eighty-eight VAPs were included for analysis; 61 (69%) were VAP-alone and 27 (31%) VAP-plus. Average age was 47.1 ± 16.7 years, 78% were male, and 93% were trauma admissions. Median hospital day of VAP diagnosis was six (interquartile range [IQR], 4-10). Nearly all patients (99%) were started on initial antibiotic agents to which the VAP organism was sensitive. Daily WBC was higher for VAP-plus compared with VAP-alone on days five, six, and seven of treatment. The maximum WBC was higher for VAP-plus (21.6 k/mcL vs. 16.1 k/mcL; p = 0.02). There were no differences in admission types, number of surgeries, or steroid use between groups. Conclusions: Providers should have increased suspicion for additional sources of infection when ICU patients with a VAP continue to have elevated WBC despite appropriate antibiotic therapy.

Attributable Mortality of Ventilator-associated Pneumonia Among Patients with COVID-19

Rationale: Patients with a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are at higher risk of ventilator-associated pneumonia (VAP) and may have an increased attributable mortality (increased or decreased risk of death if VAP occurs in a patient) and attributable fraction (proportion of deaths that are attributable to an exposure) of VAP-related mortality compared with subjects without coronavirus disease (COVID-19). Objectives: Estimation of the attributable mortality of the VAP among patients with COVID-19. Methods: Using the REA-REZO surveillance network, three groups of adult medical ICU patients were computed: control group (patients admitted between 2016 and 2019; prepandemic patients), pandemic COVID-19 group (PandeCOV⁺), and pandemic non-COVID-19 group (PandeCOV^-) admitted during 2020. The primary outcome was the estimation of attributable mortality and attributable fraction related to VAP in these patients. Using multistate modeling with causal inference, the outcomes related to VAP were also evaluated. Measurements and Main Results: A total of 64,816 patients were included in the control group, 7,442 in the PandeCOV^- group, and 1,687 in the PandeCOV⁺ group. The incidence of VAP was 14.2 (95% confidence interval [CI], 13.9 to 14.6), 18.3 (95% CI, 17.3 to 19.4), and 31.9 (95% CI, 29.8 to 34.2) per 1,000 ventilation-days in each group, respectively. Attributable mortality at 90 days was 3.15% (95%, CI, 2.04% to 3.43%), 2.91% (95% CI, -0.21% to 5.02%), and 8.13% (95% CI, 3.54% to 12.24%), and attributable fraction of mortality at 90 days was 1.22% (95% CI, 0.83 to 1.63), 1.42% (95% CI, -0.11% to 2.61%), and 9.17% (95% CI, 3.54% to 12.24%) for the control, PandeCOV^-, and PandeCOV⁺ groups, respectively. Except for the higher risk of developing VAP, the PandeCOV^- group shared similar VAP characteristics with the control group. PandeCOV⁺ patients were at lower risk of death without VAP (hazard ratio, 0.62; 95% CI, 0.52 to 0.74) than the control group. Conclusions: VAP-attributable mortality was higher for patients with COVID-19, with more than 9% of the overall mortality related to VAP.

Strategies to prevent ventilator-associated pneumonia, ventilator-associated events, and nonventilator hospital-acquired pneumonia in acute-care hospitals: 2022 Update

The purpose of this document is to highlight practical recommendations to assist acute care hospitals to prioritize and implement strategies to prevent ventilator-associated pneumonia (VAP), ventilator-associated events (VAE), and non-ventilator hospital-acquired pneumonia (NV-HAP) in adults, children, and neonates. This document updates the Strategies to Prevent Ventilator-Associated Pneumonia in Acute Care Hospitals published in 2014. This expert guidance document is sponsored by the Society for Healthcare Epidemiology (SHEA), and is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America, the American Hospital Association, the Association for Professionals in Infection Control and Epidemiology, and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise.

Novel investigational treatments for ventilator-associated pneumonia and critically ill patients in the intensive care unit

INTRODUCTION

Ventilator-associated pneumonia (VAP) is common; its prevalence has been highlighted by the Covid-19 pandemic. Even young patients can suffer severe nosocomial infection and prolonged mechanical ventilation. Multidrug-resistant bacteria can spread alarmingly fast around the globe and new antimicrobials are struggling to keep pace; hence physicians must stay abreast of new developments in the treatment of nosocomial pneumonia and VAP.

AREAS COVERED

This narrative review examines novel antimicrobial investigational drugs and their implementation in the ICU setting for VAP. The paper highlights novel approaches such as monoclonal antibody treatments for P. aeruginosa and S. aureus, and phage antibiotic synthesis. The paper also examines mechanisms of resistance in gram-negative bacteria, virulence factors and inhaled antibiotics and questions what may be on the horizon in terms of emerging treatment strategies.

EXPERT OPINION

The post-antibiotic era is rapidly approaching and the need for personalised medicine, point-of-care microbial sensitivity testing and development of biomarkers for severe infections is clear. Results from emerging and new antibiotics are encouraging, but infection control measures and de-escalation protocols must be employed to prolong their usefulness in critical illness.

Hospital-Acquired Pneumonia/Ventilator-Associated Pneumonia and Ventilator-Associated Tracheobronchitis in COVID-19

Although few studies evaluated the incidence of hospital-acquired pneumonia (HAP) or ventilator-associated tracheobronchitis in COVID-19 patients, several studies evaluated the incidence of ventilator-associated pneumonia (VAP) in these patients. Based on the results of a large multicenter European study, VAP incidence is higher in patients with SARS-CoV-2 pneumonia (36.1%), as compared with those with influenza pneumonia (22.2%), or no viral infection at intensive care unit (ICU) admission (16.5%). Potential explanation for the high incidence of VAP in COVID-19 patients includes long duration of invasive mechanical ventilation, high incidence of acute respiratory distress syndrome, and immune-suppressive treatment. Specific risk factors for VAP, including SARS-CoV-2-related pulmonary lesions, and bacteria-virus interaction in lung microbiota might also play a role in VAP pathogenesis. VAP is associated with increased mortality, duration of mechanical ventilation, and ICU length of stay in COVID-19 patients. Further studies should focus on the incidence of HAP especially in ICU non-ventilated patients, better determine the pathophysiology of these infections, and evaluate the accuracy of currently available treatment guidelines in COVID-19 patients.

New Insights into the Prevention of Hospital-Acquired Pneumonia/Ventilator-Associated Pneumonia Caused by Viruses

A fifth or more of hospital-acquired pneumonias may be attributable to respiratory viruses. The SARS-CoV-2 pandemic has clearly demonstrated the potential morbidity and mortality of respiratory viruses and the constant threat of nosocomial transmission and hospital-based clusters. Data from before the pandemic suggest the same can be true of influenza, respiratory syncytial virus, and other respiratory viruses. The pandemic has also helped clarify the primary mechanisms and risk factors for viral transmission. Respiratory viruses are primarily transmitted by respiratory aerosols that are routinely emitted when people exhale, talk, and cough. Labored breathing and coughing increase aerosol generation to a much greater extent than intubation, extubation, positive pressure ventilation, and other so-called aerosol-generating procedures. Transmission risk is proportional to the amount of viral exposure. Most transmissions take place over short distances because respiratory emissions are densest immediately adjacent to the source but then rapidly dilute and diffuse with distance leading to less viral exposure. The primary risk factors for transmission then are high viral loads, proximity, sustained exposure, and poor ventilation as these all increase net viral exposure. Poor ventilation increases the risk of long-distance transmission by allowing aerosol-borne viruses to accumulate over time leading to higher levels of exposure throughout an enclosed space. Surgical and procedural masks reduce viral exposure but do not eradicate it and thus lower but do not eliminate transmission risk. Most hospital-based clusters have been attributed to delayed diagnoses, transmission between roommates, and staff-to-patient infections. Strategies to prevent nosocomial respiratory viral infections include testing all patients upon admission, preventing healthcare providers from working while sick, assuring adequate ventilation, universal masking, and vaccinating both patients and healthcare workers.

Automatic Continuous Control of Cuff Pressure and Subglottic Secretion Suction Used Together to Prevent Pneumonia in Ventilated Patients-A Retrospective and Prospective Cohort Study

The ventilator bundle consists of multiple methods to reduce ventilator-associated pneumonia (VAP) rates in Intensive Care Units (ICU). The aim of the study was to evaluate how the continuous automatic pressure control in tapered cuffs of endotracheal/tracheostomy tubes applied along with continuous automatic subglottic secretion suction affect the incidence of VAP. In the prospective cohort (n = 198), the standard VAP bundle was modified by continuous automatic pressure control in taper-shaped cuff of endotracheal/tracheostomy tubes and subglottic secretion suction. VAP incidence, time to VAP onset, invasive mechanical ventilation days/free days, length of ICU stay, ICU mortality, and multidrug-resistant bacteria were assessed and compared to the retrospective cohort (n = 173) with the standard bundle (intermittent cuff pressure of standard cuff, lack of subglottic secretion suction). A smaller incidence of VAP (9.6% vs. 19.1%) and early onset VAP (1.5% vs. 8.1%) was found in the prospective compared to the retrospective cohort (p < 0.01). Patients in the prospective cohort were less likely to develop VAP (RR = 0.50; 95% CI: 0.29 to 0.85) and early-onset VAP (RR = 0.19; 95% CI: 0.05 to 0.64) and had longer time to onset VAP (median 9 vs. 5 days; p = 0.03). There was no significant difference (p > 0.05) between both cohorts in terms of invasive mechanical ventilation days/free days, length of ICU stay, ICU mortality and multidrug-resistant bacteria. Modification of the bundle for prevention of VAP can reduce early-onset VAP and total incidence of VAP and delay the time of VAP occurrence.

Secondary pneumonias in critically ill patients with COVID-19: risk factors and outcomes

PURPOSE OF REVIEW

The aim of this review is to provide an overview of the current evidence of secondary pneumonias in COVID-19 patients, its incidence, risk factors and impact outcomes.

RECENT FINDINGS

Early studies reported low incidence of hospital-acquired infections in COVID-19 patients. More recent large studies clearly showed that the incidence of secondary pneumonias was markedly high in patients under mechanical ventilation. Duration of mechanical ventilation, acute respiratory distress syndrome, prone position and male sex were identified as risk factors. The adjunctive therapy with steroids and immunomodulators were associated with a higher risk of pneumonia and invasive pulmonary Aspergillosis. Although secondary pneumonias seemed to be associated with poor outcomes, namely mortality, in comparison with influenza, no difference was found in heterogeneity of outcomes. Immunosuppressive therapy has been studied in several observational and randomized trials with conflicting results and the true impact on superinfections, namely secondary pneumonias, has not been properly assessed.

SUMMARY

According to the current evidence, COVID-19 patients are at an increased risk of secondary pneumonias. The impact of immunosuppressive therapies on superinfections is yet to be determined. Further studies are needed to assess the true risk of secondary infections associated with immunosuppressive therapies and to identify preventive strategies.

Systematic review of studies investigating ventilator associated pneumonia diagnostics in intensive care

Background

Ventilator-associated pneumonia (VAP) is an important diagnosis in critical care. VAP research is complicated by the lack of agreed diagnostic criteria and reference standard test criteria. Our aim was to review which reference standard tests are used to evaluate novel index tests for suspected VAP.

Methods

We conducted a comprehensive search using electronic databases and hand reference checks. The Cochrane Library, MEDLINE, CINHAL, EMBASE, and web of science were searched from 2008 until November 2018. All terms related to VAP diagnostics in the intensive treatment unit were used to conduct the search. We adopted a checklist from the critical appraisal skills programme checklist for diagnostic studies to assess the quality of the included studies.

Results

We identified 2441 records, of which 178 were selected for full-text review. Following methodological examination and quality assessment, 44 studies were included in narrative data synthesis. Thirty-two (72.7%) studies utilised a sole microbiological reference standard; the remaining 12 studies utilised a composite reference standard, nine of which included a mandatory microbiological criterion. Histopathological criteria were optional in four studies but mandatory in none.

Conclusions

Nearly all reference standards for VAP used in diagnostic test research required some microbiological confirmation of infection, with BAL culture being the most common reference standard used.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01560-0.

Relationship between ventilator-associated pneumonia and mortality in COVID-19 patients: a planned ancillary analysis of the coVAPid cohort

Background

Patients with SARS-CoV-2 infection are at higher risk for ventilator-associated pneumonia (VAP). No study has evaluated the relationship between VAP and mortality in this population, or compared this relationship between SARS-CoV-2 patients and other populations. The main objective of our study was to determine the relationship between VAP and mortality in SARS-CoV-2 patients.

Methods

Planned ancillary analysis of a multicenter retrospective European cohort. VAP was diagnosed using clinical, radiological and quantitative microbiological criteria. Univariable and multivariable marginal Cox’s regression models, with cause-specific hazard for duration of mechanical ventilation and ICU stay, were used to compare outcomes between study groups. Extubation, and ICU discharge alive were considered as events of interest, and mortality as competing event.

Findings

Of 1576 included patients, 568 were SARS-CoV-2 pneumonia, 482 influenza pneumonia, and 526 no evidence of viral infection at ICU admission. VAP was associated with significantly higher risk for 28-day mortality in SARS-CoV-2 group (adjusted HR 1.65 (95% CI 1.11–2.46), p = 0.013), but not in influenza (1.74 (0.99–3.06), p = 0.052), or no viral infection groups (1.13 (0.68–1.86), p = 0.63). VAP was associated with significantly longer duration of mechanical ventilation in the SARS-CoV-2 group, but not in the influenza or no viral infection groups. VAP was associated with significantly longer duration of ICU stay in the 3 study groups. No significant difference was found in heterogeneity of outcomes related to VAP between the 3 groups, suggesting that the impact of VAP on mortality was not different between study groups.

Interpretation

VAP was associated with significantly increased 28-day mortality rate in SARS-CoV-2 patients. However, SARS-CoV-2 pneumonia, as compared to influenza pneumonia or no viral infection, did not significantly modify the relationship between VAP and 28-day mortality.

Clinical trial registration

The study was registered at ClinicalTrials.gov, number NCT04359693.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03588-4.