Acute exacerbation of idiopathic pulmonary fibrosis: Lessons learned from acute respiratory distress syndrome?

Idiopathic pulmonary fibrosis (IPF) is a fibrotic lung disease characterized by progressive loss of lung function and poor prognosis. The so-called acute exacerbation of IPF (AE-IPF) may lead to severe hypoxemia requiring mechanical ventilation in the intensive care unit (ICU). AE-IPF shares several pathophysiological features with acute respiratory distress syndrome (ARDS), a very severe condition commonly treated in this setting. A review of the literature has been conducted to underline similarities and differences in the management of patients with AE-IPF and ARDS. During AE-IPF, diffuse alveolar damage and massive loss of aeration occurs, similar to what is observed in patients with ARDS. Differently from ARDS, no studies have yet concluded on the optimal ventilatory strategy and management in AE-IPF patients admitted to the ICU. Notwithstanding, a protective ventilation strategy with low tidal volume and low driving pressure could be recommended similarly to ARDS. The beneficial effect of high levels of positive end-expiratory pressure and prone positioning has still to be elucidated in AE-IPF patients, as well as the precise role of other types of respiratory assistance (e.g., extracorporeal membrane oxygenation) or innovative therapies (e.g., polymyxin-B direct hemoperfusion). The use of systemic drugs such as steroids or immunosuppressive agents in AE-IPF is controversial and potentially associated with an increased risk of serious adverse reactions. Common pathophysiological abnormalities and similar clinical needs suggest translating to AE-IPF the lessons learned from the management of ARDS patients. Studies focused on specific therapeutic strategies during AE-IPF are warranted

Prevalence and development of chronic critical illness in acute patients admitted to a respiratory intensive care setting

Introduction- Chronic Critical Illness (chronic CI) is a condition associated to patients surviving an episode of acute respiratory failure (ARF). The prevalence and the factors associated with the development of chronic CI in the population admitted to a Respiratory Intensive Care Unit (RICU) have not been yet elucidated. Methods- An observational prospective cohort study was undertaken at the RICU of the University Hospital of Modena (Italy). Patients mechanically ventilated with ARF in RICU were enrolled. Demographics, severity scores (APACHEII, SOFA, SAPSII), and clinical condition (septic shock, pneumonia, ARDS) were recorded on admission. Respiratory mechanics and inflammatory-metabolic blood parameters were measured both on admission and over the first week of stay. All variables were tested as predictors of chronic CI through univariate and multivariate analysis. Results- chronic CI occurred in 33 out of 100 patients observed. Higher APACHEII, the presence of septic shock, diaphragmatic dysfunction (DD) at sonography, multidrug-resistant (MDR) bacterial infection, the occurrence of a second infection during stay, and a C-reactive protein (CRP) serum level inceasing 7 days over admission were associated with chronic CI. Septic shock was the strongest predictor of chronic CI (AUC=0.92 p<0.0001). Conclusions- Chronic CI is frequent in patients admitted to RICU and mechanically ventilated due to ARF. Infection-related factors seem to play a major role as predictors of this syndrome

Early inspiratory effort assessment by esophageal manometry early predicts noninvasive ventilation outcome in de novo respiratory failure: a pilot study.

Rationale: The role of inspiratory effort has still to be determined as a potential predictors of non-invasive mechanical ventilation (NIV) failure in acute hypoxic de novo respiratory failure (AHRF). Objectives: We explore the hypothesis that inspiratory effort might be a major determinant of NIV failure in these patients. Methods: Thirty consecutive patients with AHRF admitted to a single center and candidates for a 24-hour NIV trial were enrolled. Clinical features, tidal changes in esophageal (ΔPes) and dynamic transpulmonary pressure (ΔPL), expiratory tidal volume, and respiratory rate were recorded on admission and 2-4-12-24 hours after NIV start, and were tested for correlation with outcomes. Measurements and Main Results: ΔPes and ΔPes/ΔPL were significantly lower 2 hours after NIV start in patients who successfully completed the NIV trial (n=18) compared to those who needed endotracheal intubation (n=12) [median=11 (IQR=8–15) cmH2O vs 31.5 (30–36) cmH2O, p<0.0001] while other variables differed later. ΔPes was not related to other predictors of NIV failure at baseline. NIV-induced reduction in ΔPes of 10 cmH2O or more after 2 hours of treatment was strongly associated to avoidance of intubation, and represented the most accurate predictor of treatment success (OR=15, 95%CI 2.8-110, p=0.001, AUC=0.97, 95%CI 0.91–1, p<0.0001). Conclusions: The magnitude of inspiratory effort relief as assessed by ΔPes variation within the first 2 hours of NIV was an early and accurate predictor of NIV outcome at 24 hours

Serial Ultrasound Assessment of Diaphragmatic Function and Clinical Outcome in Patients with Amyotrophic Lateral Sclerosis.

Background: Ultrasound (US) evaluation of the diaphragm may be a non-volitional useful tool in the clinical management of patients with ALS. Aim of the present study was then to evaluate the impact of serial assessment of ΔTmax index on clinical outcomes during the follow-up in these patients and to correlate non-volitional US indices and other volitional measures with these outcomes. Methods: A cohort of 39 consecutive patients with ALS was followed up to 24 months. At baseline and every 3-month spirometry (forced vital capacity-FVC), sniff inspiratory nasal pressure (SNIP), and US of the diaphragm (ΔTdi and ΔTmax) were recorded. These parameters were correlated with clinical outcomes (hypercapnia, nocturnal hypoventilation, NIV start in the following 6 month, and death within 1 year). Results: The occurrence of ΔTmax >0.75 during follow-up increased the risk for NIV (HR=5.6, p=0.001) and death (HR=3.7, p=0.0001) compared with patients with stable lower values. The evidence of diaphragmatic dysfunction, i.e. ΔTmax >0.75, occurs 3.2 month earlier than the onset of NIV. Moreover, ΔTmax >0.75 correlated with onset of nocturnal hypoventilation, NIV initiation within 6 months, and death within 12 months, similarly to FVC <50% predicted and better than other functional indices. Conclusions: Serial monitoring of diaphragmatic ΔTmax by US may be useful to predict initiation of NIV and death in patients with ALS. The occurrence of an abnormal ΔTmax value in the follow-up precedes the decision for starting NIV

Ventilatory support and mechanical properties of the fibrotic lung acting as a "squishy ball"

Protective ventilation is the cornerstone of treatment of patients with the acute respiratory distress syndrome (ARDS); however, no studies have yet established the best ventilatory strategy to adopt when patients with acute exacerbation of interstitial lung disease (AE-ILD) are admitted to the intensive care unit. Due to the severe impairment of the respiratory mechanics, the fibrotic lung is at high risk of developing ventilator-induced lung injury, regardless of the lung fibrosis etiology. The purpose of this review is to analyze the effects of mechanical ventilation in AE-ILD and to increase the knowledge on the characteristics of fibrotic lung during artificial ventilation, introducing the concept of "squishy ball lung". The role of positive end-expiratory pressure is discussed, proposing a "lung resting strategy" as opposed to the "open lung approach". The review also discusses the practical management of AE-ILD patients discussing illustrative clinical cases

Molecular mechanisms and cellular contribution from lung fibrosis to lung cancer development.

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrosing interstitial lung 28 disease (ILD) of unknown etiology, with a median survival of 2-4 years from the time of diagnosis. 29 Although IPF has unknown etiology by definition, there have been identified several risks factors 30 increasing the probability of the onset and progression of the disease in IPF patients such as cigarette 31 smoking and environmental risks factors associated to domestic and occupational exposure. Among 32 them, cigarette smoking together with concomitant emphysema might predispose IPF patients to 33 lung cancer (LC), mostly to non-small cell lung cancer (NSCLC), increasing the risk of lung cancer 34 development. To this purpose, IPF and LC share several cellular and molecular processes driving 35 the progression of both pathologies such as fibroblast transition proliferation and activation, endo- 36 plasmic reticulum stress, oxidative stress, and many genetic and epigenetic markers that predispose 37 the IPF patients to LC development. Nintedanib, a tyrosine-kinase inhibitor, was firstly developed 38 as an anticancer drug and then recognized as an anti-fibrotic agent based on the common target 39 molecular pathway. In this review our aim is to describe the updated studies on common cellular 40 and molecular mechanisms between IPF and lung cancer, whose knowledge might help to find 41 novel therapeutic targets for this disease combination

Dissecting the Role of Mesenchymal Stem Cells in Idiopathic Pulmonary Fibrosis:Cause or Solution

Idiopathic pulmonary fibrosis (IPF) is one of the most aggressive forms of idiopathic interstitial pneumonias, characterized by chronic and progressive fibrosis subverting the lung’s architecture, pulmonary functional decline, progressive respiratory failure, and high mortality (median survival 3 years after diagnosis). Among the mechanisms associated with disease onset and progression, it has been hypothesized that IPF lungs might be affected either by a regenerative deficit of the alveolar epithelium or by a dysregulation of repair mechanisms in response to alveolar and vascular damage. This latter might be related to the progressive dysfunction and exhaustion of the resident stem cells together with a process of cellular and tissue senescence. The role of endogenous mesenchymal stromal/stem cells (MSCs) resident in the lung in the homeostasis of these mechanisms is still a matter of debate. Although endogenous MSCs may play a critical role in lung repair, they are also involved in cellular senescence and tissue ageing processes with loss of lung regenerative potential. In addition, MSCs have immunomodulatory properties and can secrete anti-fibrotic factors. Thus, MSCs obtained from other sources administered systemically or directly into the lung have been investigated for lung epithelial repair and have been explored as a potential therapy for the treatment of lung diseases including IPF. Given these multiple potential roles of MSCs, this review aims both at elucidating the role of resident lung MSCs in IPF pathogenesis and the role of administered MSCs from other sources for potential IPF therapies

Risk factors for pulmonary air leak and clinical prognosis in patients with COVID-19 related acute respiratory failure: a retrospective matched control study.

Background- The role of excessive inspiratory effort in promoting alveolar and pleural rupture resulting in air leak (AL) in patients with SARS-CoV-2 induced acute respiratory failure (ARF) while on spontaneous breathing is undetermined. Methods- Among all patients with COVID-19 related ARF admitted to a respiratory intensive care unit (RICU) and receiving non-invasive respiratory support, those developing an AL were and matched 1:1 (by means of PaO2/FiO2 ratio, age, body mass index-BMI and subsequent organ failure assessment [SOFA]) with a comparable population who did not (NAL group). Esophageal pressure (ΔPes) and dynamic transpulmonary pressure (ΔPL) swings were compared between groups. Risk factors affecting AL onset were evaluated. The composite outcome of ventilator-free-days (VFD) at day 28 (including ETI, mortality, tracheostomy) was compared between groups. Results- AL and NAL groups (n=28) showed similar ΔPes, whereas AL had higher ΔPL (20 [16‐21] and 17 [11‐20], p=0.01 respectively). Higher ΔPL (OR=1.5 95%CI[1‐1.8], p=0.01), positive end‐expiratory pressure (OR=2.4 95%CI[1.2‐5.9], p=0.04) and pressure support (OR=1.8 95%CI[1.1-3.5], p=0.03), D-dimer on admission (OR=2.1 95%CI[1.3-9.8], p=0.03), and features suggestive of consolidation on computed tomography scan (OR=3.8 95%CI[1.1-15], p= 0.04) were all significantly associated with AL. A lower VFD score resulted in a higher risk (HR=3.7 95%CI [1.2-11.3], p=0.01) in the AL group compared with NAL. RICU stay and 90-day mortality were also higher in the AL group compared with NAL. Conclusions- In spontaneously breathing patients with COVID‐19 related ARF, higher levels of ΔPL, blood D‐dimer, NIV delivery pressures and a consolidative lung pattern were associated with AL onset

Nasal pressure swings as the measure of inspiratory effort in spontaneously breathing patients with de novo acute respiratory failure.

Background- Excessive inspiratory effort could translate into self-inflicted lung injury, thus worsening clinical outcomes of spontaneously breathing patients with acute respiratory failure (ARF). Although esophageal manometry is a reliable method to estimate the magnitude of inspiratory effort, procedural issues significantly limit its use in daily clinical practice. The aim of this study is to describe the correlation between esophageal pressure swings (\u394P es ) and nasal (\u394P nos ) as a potential measure of inspiratory effort in spontaneously breathing patients with de novo ARF. Methods- From January 1 st , 2021 to September 1 st , 2021, 61 consecutive patients with ARF (83.6% related to COVID-19) admitted to the Respiratory Intensive Care Unit (RICU) of the University Hospital of Modena (Italy) and candidate to escalation of noninvasive respiratory support (NRS) were enrolled. Clinical features and tidal changes in esophageal and nasal pressure were recorded on admission and 24 hours after starting NRS. Correlation between \u394P es and \u394P nos served as primary outcome. The effect of \u394P nos measurements on respiratory rate and \u394P es was also assessed. Results- \u394P es and \u394P nos were strongly correlated at admission (R 2 =0.88, p<0.001) and 24 hours apart (R 2 =0.94, p<0.001). The nasal plug insertion and the mouth closure required for \u394P nos measurement did not result in significant change of respiratory rate and \u394P es . The correlation between measures at 24 hours remained significant even after splitting the study population according to the type of NRS (high-flow nasal cannulas [R 2 =0.79, p<0.001] or non-invasive ventilation [R 2 =0.95, p<0.001]). Conclusions- In a cohort of patients with ARF, nasal pressure swings did not alter respiratory mechanics in the short term and were highly correlated with esophageal pressure swings during spontaneous tidal breathing. \u394P nos might warrant further investigation as a measure of inspiratory effort in patients with ARF