Gourab Choudhury

Validation of the Infectious Diseases Society of America/American Thoratic Society Minor Criteria for Intensive Care Unit Admission in Community-Acquired Pneumonia Patients Without Major Criteria or Contraindications to Intensive Care Unit Care

BACKGROUND The 2007 Infectious Disease Society of America/American Thoracic Society (IDSA/ATS) guidelines for community-acquired pneumonia (CAP) recommended new criteria to guide admission to the intensive care unit (ICU) for patients with this condition. Although the major criteria (requirement for mechanical ventilation or septic shock requiring vasopressor support) are well established, the value of the minor criteria alone have not been fully validated. METHODS We performed a prospective observational study of consecutive adult patients with CAP admitted to NHS Lothian (Scotland, United Kingdom). Patients meeting the IDSA/ATS major criteria on admission were excluded, along with patients not suitable for ICU care owing to advanced directives or major comorbid illnesses. Performance characteristics for the IDSA/ATS minor criteria were calculated and compared with those for alternative scoring systems identified in the literature. Two definitions of severe CAP were used as primary end points: ICU admission, and subsequent requirement for mechanical ventilation or vasopressor support (MV/VS); 30-day mortality was a secondary outcome. RESULTS The study included 1062 patients with CAP potentially eligible for ICU admission. Each of the 9 minor criteria was associated with increased risk of MV/VS and 30-day mortality in univariate analysis. Two hundred seven patients had ≥ 3 minor criteria (19.5%). The IDSA/ATS 2007 criteria had an area under the receiver operating characteristic curve of 0.85 (0.82-0.88) for prediction of MV/VS, 0.85 (0.82-0.88) for prediction of ICU admission, and 0.78 (0.74-0.82) for prediction of 30-day mortality. The IDSA/ATS 2007 criteria were at least equivalent to more established scoring systems for prediction of MV/VS and ICU admission and equivalent to alternative scoring systems for predicting 30-day mortality in this patient population. CONCLUSIONS In a population of patients with CAP without contraindications to ICU care, the IDSA/ATS minor criteria predict subsequent requirement for MV/VS, ICU admission, and 30-day mortality.

Comorbidities and Systemic Effects of Chronic Obstructive Pulmonary Disease

Although primarily a lung disease, chronic obstructive pulmonary disease (COPD) is now recognized to have extrapulmonary effects on distal organs, the so-called systemic effects and comorbidities of COPD. Skeletal muscle dysfunction, nutritional abnormalities including weight loss, cardiovascular complications, metabolic complications, and osteoporosis, among others, are all well-recognized associations in COPD. These extrapulmonary effects add to the burden of mortality and morbidity in COPD and therefore should be actively looked for, assessed, and treated.

Ageing and the border between health and disease

Ageing is associated with a progressive degeneration of the tissues, which has a negative impact on the structure and function of vital organs and is among the most important known risk factors for most chronic diseases. Since the proportion of the world’s population aged >60 years will double in the next four decades, this will be accompanied by an increased incidence of chronic age-related diseases that will place a huge burden on healthcare resources. There is increasing evidence that many chronic inflammatory diseases represent an acceleration of the ageing process. Chronic pulmonary diseases represents an important component of the increasingly prevalent multiple chronic debilitating diseases, which are a major cause of morbidity and mortality, particularly in the elderly. The lungs age and it has been suggested that chronic obstructive pulmonary disease (COPD) is a condition of accelerated lung ageing and that ageing may provide a mechanistic link between COPD and many of its extrapulmonary effects and comorbidities. In this article we will describe the physiological changes and mechanisms of ageing, with particular focus on the pulmonary effects of ageing and how these may be relevant to the development of COPD and its major extrapulmonary manifestations. Premature ageing of the lung may constitute pathogenetic mechanisms contributing to COPD http://ow.ly/BGd52

Physician judgement is a crucial adjunct to pneumonia severity scores in low-risk patients

This study investigates the reasons for hospitalisation in patients with low-risk (CURB-65 score 0–1) community-acquired pneumonia (CAP), with a view to identifying the potential for improving outpatient management. As part of a prospective observational study of CAP, we evaluated reasons for hospitalisation in these low-risk patients. 565 patients had low-risk CAP and 420 of these were admitted (for >12 h). 39.3% had additional markers of severity justifying admission, 29.5% of the admissions were required for further management that could not be provided rapidly in the community, 11.9% had unsafe social circumstances and 19.3% had no clinical reason justifying hospitalisation. 30-day mortality was increased in patients with additional severity markers (6.7%), which was significantly higher compared with 0% for patients awaiting investigations (p=0.009) and 0% without a clear indication for hospitalisation (p=0.04). In a logistic regression analysis, parameters associated with 30-day mortality were chronic cardiac comorbidity (adjusted odds ratio (aOR) 5.73, 95% CI 1.52–21.6; p=0.01), acidosis (aOR 5.14, 95% CI 1.44–18.3; p=0.01), hypoxia (aOR 9.86, 95% CI 2.39–40.7; p=0.002) and multilobar chest radiograph shadowing (aOR 4.54, 95% CI 1.21–17.1; p=0.03). This study supports recommendations from international guidelines that pneumonia severity scores should be used as an adjunct to clinical judgement, when deciding on hospitalisation.

Quantification of lung PET images: challenges and opportunities.

Millions of people are affected by respiratory diseases, leading to a significant health burden globally. Because of the current insufficient knowledge of the underlying mechanisms that lead to the development and progression of respiratory diseases, treatment options remain limited. To overcome this limitation and understand the associated molecular changes, noninvasive imaging techniques such as PET and SPECT have been explored for biomarker development, with 18F-FDG PET imaging being the most studied. The quantification of pulmonary molecular imaging data remains challenging because of variations in tissue, air, blood, and water fractions within the lungs. The proportions of these components further differ depending on the lung disease. Therefore, different quantification approaches have been proposed to address these variabilities. However, no standardized approach has been developed to date. This article reviews the data evaluating 18F-FDG PET quantification approaches in lung diseases, focusing on methods to account for variations in lung components and the interpretation of the derived parameters. The diseases reviewed include acute respiratory distress syndrome, chronic obstructive pulmonary disease, and interstitial lung diseases such as idiopathic pulmonary fibrosis. Based on review of prior literature, ongoing research, and discussions among the authors, suggested considerations are presented to assist with the interpretation of the derived parameters from these approaches and the design of future studies.

Role of Inflammation and Oxidative Stress in the Pathology of Ageing in COPD: Potential Therapeutic Interventions

ABSTRACT Ageing is defined as a progressive decline of homeostasis that occurs after the reproductive phase of life is complete, which is thought to arise because of impaired DNA repair following damage. This leads to an increased risk of disease or death. Ageing is one of the most important risk factors for most chronic diseases. Chronic obstructive pulmonary disease (COPD) represents an important component of the increasingly prevalent multiple chronic debilitating diseases that are a major cause of morbidity and mortality, particularly in the elderly. There is increasing evidence that the pathogenesis of COPD is linked to an accelerated ageing process. This review discusses the evidence supporting a number of mechanisms, including oxidative stress and ageing, in the pathogenesis of COPD. Greater understanding of these mechanisms leads to novel therapeutic interventions targeted at this heterogeneous disease.

S20 18f-fluorodeoxyglucose (18fdg) Pet Pulmonary Imaging: Comparative Methodology In Copd Patients

Introduction 18FDG PET/CT imaging may be a useful tool to study COPD and lung inflammation; however the optimal protocol for this imaging biomarker has yet to be established. Method We aimed to develop a combined 18FDG-PET/CT imaging protocol optimised to quantify lung inflammation. Six patients with moderate-to-severe COPD underwent dynamic 18FDG-PET imaging combined with blood sampling (both arterial and venous over 60 min) to determine the localised plasma activity time curve. High resolution CT (HRCT) was utilised to segmentate the lung and determine areas of emphysema. 3 sets of comparative input functions were analysed (arterial, venous and image derived arterial input functions). 18FDG kinetics was fitted using the Patlak method. Results Similar results were obtained using time activity curves from all three input functions. The arterial input was always found to be slightly higher than the others (Figure 1). Patlak analysis of the time-activity curves for each of the CT derived lung lobes allowed generation of images of slope (influx constant Ki) and intercept (initial volume of distribution) (Figure 1). The acquisition of HRCT co-registered to FDG-PET allows more accurate demarcation and quantification of FDG in emphysematous areas of the lung. Attempt to improve the signal by excluding voxels without COPD tissue (-935 to -300 HU) has been undertaken as well. The reproducibility of this technique is currently being studied where 20 patients are being scanned twice 4 weeks apart and compared to a baseline scan from 5 healthy controls. Abstract S20 Figure 1 Shows an example of time activity curves from arterial, venous and image derived techniques (on left) and (on right) a Patlak image from venous plasma slope (1st row), intercept (2nd row) and CT (3rd row) Conclusion 18FDG PET/CT imaging has the potential to be a non-invasive biomarker of lung inflammation in COPD.