The formation and function of the neutrophil phagosome.

Neutrophils are the most abundant circulating leukocyte and are crucial to the initial innate immune response to infection. One of their key pathogen-eliminating mechanisms is phagocytosis, the process of particle engulfment into a vacuole-like structure called the phagosome. The antimicrobial activity of the phagocytic process results from a collaboration of multiple systems and mechanisms within this organelle, where a complex interplay of ion fluxes, pH, reactive oxygen species, and antimicrobial proteins creates a dynamic antimicrobial environment. This complexity, combined with the difficulties of studying neutrophils ex vivo, has led to gaps in our knowledge of how the neutrophil phagosome optimizes pathogen killing. In particular, controversy has arisen regarding the relative contribution and integration of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-derived antimicrobial agents and granule-delivered antimicrobial proteins. Clinical syndromes arising from dysfunction in these systems in humans allow useful insight into these mechanisms, but their redundancy and synergy add to the complexity. In this article, we review the current knowledge regarding the formation and function of the neutrophil phagosome, examine new insights into the phagosomal environment that have been permitted by technological advances in recent years, and discuss aspects of the phagocytic process that are still under debate.

Invasive Pulmonary Aspergillosis in Hospital and Ventilator-Associated Pneumonias.

Pneumonia is the commonest nosocomial infection complicating hospital stay, with both non-ventilated hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) occurring frequently amongst patients in intensive care. Aspergillus is an increasingly recognized pathogen amongst patients with HAP and VAP, and is associated with significantly increased mortality if left untreated.Invasive pulmonary aspergillosis (IPA) was originally identified in patients who had been profoundly immunosuppressed, however, this disease can also occur in patients with relative immunosuppression such as critically ill patients in intensive care unit (ICU). Patients in ICU commonly have several risk factors for IPA, with the inflamed pulmonary environment providing a niche for aspergillus growth.An understanding of the true prevalence of this condition amongst ICU patients, and its specific rate in patients with HAP or VAP is hampered by difficulties in diagnosis. Establishing a definitive diagnosis requires tissue biopsy, which is seldom practical in critically ill patients, so imperfect proxy measures are required. Clinical and radiological findings in ventilated patients are frequently non-specific. The best-established test is galactomannan antigen level in bronchoalveolar lavage fluid, although this must be interpreted in the clinical context as false positive results can occur. Acknowledging these limitations, the best estimates of the prevalence of IPA range from 0.3 to 5% amongst all ICU patients, 12% amongst patients with VAP and 7 to 28% amongst ventilated patients with influenza.Antifungal triazoles including voriconazole are the first-line therapy choice in most cases. Amphotericin has excellent antimold coverage, but a less advantageous side effect profile. Echinocandins are less effective against IPA, but may play a role in rescue therapy, or as an adjuvant to triazole therapy.A high index of suspicion for IPA should be maintained when investigating patients with HAP or VAP, especially when they have specific risk factors or are not responding to appropriate empiric antibacterial therapy.

Perspectives of patients, family members, health professionals and the public on the impact of COVID-19 on mental health.

BACKGROUND: The coronavirus (COVID-19) pandemic has seen a global surge in anxiety, depression, post-traumatic stress disorder (PTSD), and stress. AIMS: This study aimed to describe the perspectives of patients with COVID-19, their family, health professionals, and the general public on the impact of COVID-19 on mental health. METHODS: A secondary thematic analysis was conducted using data from the COVID-19 COS project. We extracted data on the perceived causes and impact of COVID-19 on mental health from an international survey and seven online consensus workshops. RESULTS: We identified four themes (with subthemes in parenthesis): anxiety amidst uncertainty (always on high alert, ebb and flow of recovery); anguish of a threatened future (intense frustration of a changed normality, facing loss of livelihood, trauma of ventilation, a troubling prognosis, confronting death); bearing responsibility for transmission (fear of spreading COVID-19 in public; overwhelming guilt of infecting a loved one); and suffering in isolation (severe solitude of quarantine, sick and alone, separation exacerbating grief). CONCLUSION: We found that the unpredictability of COVID-19, the fear of long-term health consequences, burden of guilt, and suffering in isolation profoundly impacted mental health. Clinical and public health interventions are needed to manage the psychological consequences arising from this pandemic.

Core Outcome Measures for Trials in People With Coronavirus Disease 2019: Respiratory Failure, Multiorgan Failure, Shortness of Breath, and Recovery.

OBJECTIVES: Respiratory failure, multiple organ failure, shortness of breath, recovery, and mortality have been identified as critically important core outcomes by more than 9300 patients, health professionals, and the public from 111 countries in the global coronavirus disease 2019 core outcome set initiative. The aim of this project was to establish the core outcome measures for these domains for trials in coronavirus disease 2019. DESIGN: Three online consensus workshops were convened to establish outcome measures for the four core domains of respiratory failure, multiple organ failure, shortness of breath, and recovery. SETTING: International. PATIENTS: About 130 participants (patients, public, and health professionals) from 17 countries attended the three workshops. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Respiratory failure, assessed by the need for respiratory support based on the World Health Organization Clinical Progression Scale, was considered pragmatic, objective, and with broad applicability to various clinical scenarios. The Sequential Organ Failure Assessment was recommended for multiple organ failure, because it was routinely used in trials and clinical care, well validated, and feasible. The Modified Medical Research Council measure for shortness of breath, with minor adaptations (recall period of 24 hr to capture daily fluctuations and inclusion of activities to ensure relevance and to capture the extreme severity of shortness of breath in people with coronavirus disease 2019), was regarded as fit for purpose for this indication. The recovery measure was developed de novo and defined as the absence of symptoms, resumption of usual daily activities, and return to the previous state of health prior to the illness, using a 5-point Likert scale, and was endorsed. CONCLUSIONS: The coronavirus disease 2019 core outcome set recommended core outcome measures have content validity and are considered the most feasible and acceptable among existing measures. Implementation of the core outcome measures in trials in coronavirus disease 2019 will ensure consistency and relevance of the evidence to inform decision-making and care of patients with coronavirus disease 2019.

International Survey to Establish Prioritized Outcomes for Trials in People With Coronavirus Disease 2019.

OBJECTIVES: There are over 4,000 trials conducted in people with coronavirus disease 2019. However, the variability of outcomes and the omission of patient-centered outcomes may diminish the impact of these trials on decision-making. The aim of this study was to generate a consensus-based, prioritized list of outcomes for coronavirus disease 2019 trials. DESIGN: In an online survey conducted in English, Chinese, Italian, Portuguese, and Spanish languages, adults with coronavirus disease 2019, their family members, health professionals, and the general public rated the importance of outcomes using a 9-point Likert scale (7-9, critical importance) and completed a Best-Worst Scale to estimate relative importance. Participant comments were analyzed thematically. SETTING: International. SUBJECTS: Adults 18 years old and over with confirmed or suspected coronavirus disease 2019, their family members, members of the general public, and health professionals (including clinicians, policy makers, regulators, funders, and researchers). INTERVENTIONS: None. MEASUREMENTS: None. MAIN RESULTS: In total, 9,289 participants from 111 countries (776 people with coronavirus disease 2019 or family members, 4,882 health professionals, and 3,631 members of the public) completed the survey. The four outcomes of highest priority for all three groups were: mortality, respiratory failure, pneumonia, and organ failure. Lung function, lung scarring, sepsis, shortness of breath, and oxygen level in the blood were common to the top 10 outcomes across all three groups (mean > 7.5, median ≥ 8, and > 70% of respondents rated the outcome as critically important). Patients/family members rated fatigue, anxiety, chest pain, muscle pain, gastrointestinal problems, and cardiovascular disease higher than health professionals. Four themes underpinned prioritization: fear of life-threatening, debilitating, and permanent consequences; addressing knowledge gaps; enabling preparedness and planning; and tolerable or infrequent outcomes. CONCLUSIONS: Life-threatening respiratory and other organ outcomes were consistently highly prioritized by all stakeholder groups. Patients/family members gave higher priority to many patient-reported outcomes compared with health professionals.

Core Outcomes Set for Trials in People With Coronavirus Disease 2019.

OBJECTIVES: The outcomes reported in trials in coronavirus disease 2019 are extremely heterogeneous and of uncertain patient relevance, limiting their applicability for clinical decision-making. The aim of this workshop was to establish a core outcomes set for trials in people with suspected or confirmed coronavirus disease 2019. DESIGN: Four international online multistakeholder consensus workshops were convened to discuss proposed core outcomes for trials in people with suspected or confirmed coronavirus disease 2019, informed by a survey involving 9,289 respondents from 111 countries. The transcripts were analyzed thematically. The workshop recommendations were used to finalize the core outcomes set. SETTING: International. SUBJECTS: Adults 18 years old and over with confirmed or suspected coronavirus disease 2019, their family members, members of the general public and health professionals (including clinicians, policy makers, regulators, funders, researchers). INTERVENTIONS: None. MEASUREMENTS: None. MAIN RESULTS: Six themes were identified. "Responding to the critical and acute health crisis" reflected the immediate focus on saving lives and preventing life-threatening complications that underpinned the high prioritization of mortality, respiratory failure, and multiple organ failure. "Capturing different settings of care" highlighted the need to minimize the burden on hospitals and to acknowledge outcomes in community settings. "Encompassing the full trajectory and severity of disease" was addressing longer term impacts and the full spectrum of illness (e.g. shortness of breath and recovery). "Distinguishing overlap, correlation and collinearity" meant recognizing that symptoms such as shortness of breath had distinct value and minimizing overlap (e.g. lung function and pneumonia were on the continuum toward respiratory failure). "Recognizing adverse events" refers to the potential harms of new and evolving interventions. "Being cognizant of family and psychosocial wellbeing" reflected the pervasive impacts of coronavirus disease 2019. CONCLUSIONS: Mortality, respiratory failure, multiple organ failure, shortness of breath, and recovery are critically important outcomes to be consistently reported in coronavirus disease 2019 trials.

The Effects of Escalation of Respiratory Support and Prolonged Invasive Ventilation on Outcomes of Cardiac Surgical Patients: A Retrospective Cohort Study.

OBJECTIVES: The aim of this study was to determine the effects of escalation of respiratory support and prolonged postoperative invasive ventilation on patient-centered outcomes, and identify perioperative factors associated with these 2 respiratory complications. DESIGN: A retrospective cohort analysis of cardiac surgical patients admitted to the cardiothoracic intensive care unit (ICU) between August 2015 and January 2018. Escalation of respiratory support was defined as "unplanned continuous positive airway pressure," "non-invasive ventilation," or "reintubation" after surgery; prolonged invasive ventilation was defined as "invasive ventilation beyond the first 12 hours following surgery." The primary endpoint was the composite of escalation of respiratory support and prolonged ventilation. SETTING: Tertiary cardiothoracic ICU. PARTICIPANTS: A total of 2,098 patients were included and analyzed. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The composite of escalation of support or prolonged ventilation occurred in 509 patients (24.3%). Patients who met the composite had higher mortality (2.9% v 0.1%; p < 0.001) and longer median [interquartile range] length of ICU (2.1 [1.0-4.9] v 0.9 [0.8-1.0] days; p < 0.0001) and hospital (10.6 [8.0-16.0] v 7.2 [6.2-10.0] days; p < 0.0001) stay. Hypoxemia and anemia on admission to ICU were the only 2 factors independently associated with the need for escalation of respiratory support or prolonged invasive ventilation. CONCLUSIONS: Escalation of respiratory support or prolonged invasive ventilation is frequently seen in cardiac surgery patients and is highly associated with increased mortality and morbidity. Hypoxemia and anemia on admission to the ICU are potentially modifiable factors associated with escalation of respiratory support or prolonged invasive ventilation.

Diagnostic accuracy of pulmonary host inflammatory mediators in the exclusion of ventilator-acquired pneumonia.

BACKGROUND: Excessive use of empirical antibiotics is common in critically ill patients. Rapid biomarker-based exclusion of infection may improve antibiotic stewardship in ventilator-acquired pneumonia (VAP). However, successful validation of the usefulness of potential markers in this setting is exceptionally rare. OBJECTIVES: We sought to validate the capacity for specific host inflammatory mediators to exclude pneumonia in patients with suspected VAP. METHODS: A prospective, multicentre, validation study of patients with suspected VAP was conducted in 12 intensive care units. VAP was confirmed following bronchoscopy by culture of a potential pathogen in bronchoalveolar lavage fluid (BALF) at >10(4) colony forming units per millilitre (cfu/mL). Interleukin-1 beta (IL-1ß), IL-8, matrix metalloproteinase-8 (MMP-8), MMP-9 and human neutrophil elastase (HNE) were quantified in BALF. Diagnostic utility was determined for biomarkers individually and in combination. RESULTS: Paired BALF culture and biomarker results were available for 150 patients. 53 patients (35%) had VAP and 97 (65%) patients formed the non-VAP group. All biomarkers were significantly higher in the VAP group (p<0.001). The area under the receiver operator characteristic curve for IL-1ß was 0.81; IL-8, 0.74; MMP-8, 0.76; MMP-9, 0.79 and HNE, 0.78. A combination of IL-1ß and IL-8, at the optimal cut-point, excluded VAP with a sensitivity of 100%, a specificity of 44.3% and a post-test probability of 0% (95% CI 0% to 9.2%). CONCLUSIONS: Low BALF IL-1ß in combination with IL-8 confidently excludes VAP and could form a rapid biomarker-based rule-out test, with the potential to improve antibiotic stewardship.

A randomized controlled trial of peripheral blood mononuclear cell depletion in experimental human lung inflammation.

RATIONALE: Depletion of monocytes reduces LPS-induced lung inflammation in mice, suggesting monocytes as potential therapeutic targets in acute lung injury. OBJECTIVES: To investigate whether depletion of circulating blood monocytes has beneficial effects on markers of systemic and pulmonary inflammation in a human model of acute lung inflammation. METHODS: A total of 30 healthy volunteers were enrolled in a randomized controlled trial. Volunteers inhaled LPS at baseline, and were randomized to receive active mononuclear cell depletion by leukapheresis, or sham leukapheresis, in a double-blind fashion (15 volunteers per group). Serial blood counts were measured, bronchoalveolar lavage (BAL) was performed at 9 hours, and [(18)F]fluorodeoxyglucose positron emission tomography at 24 hours. The primary endpoint was the increment in circulating neutrophils at 8 hours. MEASUREMENTS AND MAIN RESULTS: As expected, inhalation of LPS induced neutrophilia and an up-regulation of inflammatory mediators in the blood and lungs of all volunteers. There was no significant difference between the depletion and sham groups in the mean increment in blood neutrophil count at 8 hours (6.16 × 10(9)/L and 6.15 × 10(9)/L, respectively; P = 1.00). Furthermore, there were no significant differences in BAL neutrophils or protein, positron emission tomography-derived measures of global lung inflammation, or cytokine levels in plasma or BAL supernatant between the study groups. No serious adverse events occurred, and no symptoms were significantly different between the groups. CONCLUSIONS: These findings do not support a role for circulating human monocytes in the early recruitment of neutrophils during LPS-mediated acute lung inflammation in humans.