Bench testing of a new hyperbaric chamber ventilator at different atmospheric pressures

Purpose: Providing mechanical ventilation is challenging at supra-atmospheric pressure. The higher gas density increases resistance, reducing the flow delivered by the ventilator. A new hyperbaric ventilator (Siaretron IPER 1000) is said to compensate for these effects automatically. The aim of this bench test study was to validate the compensation, define its limits and provide details on the ventilator's output at varied atmospheric pressures. Methods: Experiments were conducted inside a multiplace hyperbaric chamber at 1, 2.2, 2.8 and 4 atmospheres absolute (ATA), with the ventilator connected to a test lung. Transducers were recalibrated at each ATA level. Various ventilator settings were tested in volume and pressure control modes. Measured tidal volumes were compared with theoretical predictions based on gas laws. Results: Results confirmed the ventilator's ability to provide compensation, but also identified its limits. The compensation range could be predicted and depended on the maximal flow attainable, decreasing linearly with increasing atmospheric pressure. With settings inside the range, tidal volumes approximated set values (mean error 10±5%). With settings outside the range, the volume was limited to the predicted maximal value calculated from maximal flow. A practical guide for clinicians is provided. Conclusion: The IPER 1000 ventilator attempted to deliver stable tidal volume by adjusting the opening of the inspiratory valve in proportion to atmospheric pressure. Adequate compensation was observed, albeit only within a predictable range, which can be reliably predicted for each setting and ATA level combination. Setting a tidal volume outside this range can result in an unwanted decrease in minute ventilatio

Usefulness of Lung Ultrasound in Paediatric Respiratory Diseases

Respiratory infection diseases are among the major causes of morbidity and mortality in children. Diagnosis is focused on clinical presentation, yet signs and symptoms are not specific and there is a need for new non-radiating diagnostic tools. Among these, lung ultrasound (LUS) has recently been included in point-of-care protocols showing interesting results. In comparison to other imaging techniques, such as chest X-ray and computed tomography, ultrasonography does not use ionizing radiations. Therefore, it is particularly suitable for clinical follow-up of paediatric patients. LUS requires only 5–10 min and allows physicians to make quick decisions about the patient’s management. Nowadays, LUS has become an early diagnostic tool to detect pneumonia during the COVID-19 pandemic. In this narrative review, we show the most recent scientific literature about advantages and limits of LUS performance in children. Furthermore, we discuss the major paediatric indications separately, with a paragraph fully dedicated to COVID-19. Finally, we mention potential future perspectives about LUS application in paediatric respiratory diseases

Distinct Mechanical Properties of the Respiratory System Evaluated by Forced Oscillation Technique in Acute Exacerbation of COPD and Acute Decompensated Heart Failure

Discriminating between cardiac and pulmonary dyspnea is essential for patients’ management. We investigated the feasibility and ability of forced oscillation techniques (FOT) in distinguishing between acute exacerbation of COPD (AECOPD), and acute decompensated heart failure (ADHF) in a clinical emergency setting. We enrolled 49 patients admitted to the emergency department (ED) for dyspnea and acute respiratory failure for AECOPD, or ADHF, and 11 healthy subjects. All patients were able to perform bedside FOT measurement. Patients with AECOPD showed a significantly higher inspiratory resistance at 5 Hz, Xrs5 (179% of predicted, interquartile range, IQR 94–224 vs. 100 IQR 67–149; p = 0.019), and a higher inspiratory reactance at 5 Hz (151%, IQR 74–231 vs. 57 IQR 49–99; p = 0.005) than patients with ADHF. Moreover, AECOPD showed higher heterogeneity of ventilation (respiratory system resistance difference at 5 and 19 Hz, Rrs5-19: 1.49 cmH2O/(L/s), IQR 1.03–2.16 vs. 0.44 IQR 0.22–0.76; p = 0.030), and a higher percentage of flow limited breaths compared to ADHF (10%, IQR 0–100 vs. 0 IQR 0–12; p = 0.030). FOT, which resulted in a suitable tool to be used in the ED setting, has the ability to identify distinct mechanical properties of the respiratory system in AECOPD and ADHF

Management of acute respiratory failure in interstitial lung diseases: overview and clinical insights

Abstract Background Interstitial lung diseases (ILDs) are a heterogeneous group of diseases characterized by widespread fibrotic and inflammatory abnormalities of the lung. Respiratory failure is a common complication in advanced stages or following acute worsening of the underlying disease. Aim of this review is to evaluate the current evidence in determining the best management of acute respiratory failure (ARF) in ILDs. Methods A literature search was performed in the Medline/PubMed and EMBASE databases to identify studies that investigated the management of ARF in ILDs (the last search was conducted on November 2017). Results In managing ARF, it is important to establish an adequate diagnostic and therapeutic management depending on whether the patient has an underlying known chronic ILD or ARF is presenting in an unknown or de novo ILD. In the first case both primary causes, such as acute exacerbations of the disease, and secondary causes, including concomitant pulmonary infections, fluid overload and pulmonary embolism need to be investigated. In the second case, a diagnostic work-up that includes investigations in regards to ILD etiology, such as autoimmune screening and bronchoalveolar lavage, should be performed, and possible concomitant causes of ARF have to be ruled out. Oxygen supplementation and ventilatory support need to be titrated according to the severity of ARF and patients’ therapeutic options. High-Flow Nasal oxygen might potentially be an alternative to conventional oxygen therapy in patients requiring both high flows and high oxygen concentrations to correct hypoxemia and control dyspnea, however the evidence is still scarce. Neither Non-Invasive Ventilation (NIV) nor Invasive Mechanical Ventilation (IMV) seem to change the poor outcomes associated to advanced stages of ILDs. However, in selected patients, such as those with less severe ARF, a NIV trial might help in the early recognition of NIV-responder patients, who may present a better short-term prognosis. More invasive techniques, including IMV and Extracorporeal Membrane Oxygenation, should be limited to patients listed for lung transplant or with reversible causes of ARF. Conclusions Despite the overall poor prognosis of ARF in ILDs, a personalized approach may positively influence patients’ management, possibly leading to improved outcomes. However, further studies are warranted

Long COVID in Children: A Multidisciplinary Review

Long COVID syndrome has emerged as a long-lasting consequence of acute SARS-CoV-2 infection in adults. In addition, children may be affected by Long COVID, with potential clinical issues in different fields, including problems in school performance and daily activities. Yet, the pathophysiologic bases of Long COVID in children are largely unknown, and it is difficult to predict who will develop the syndrome. In this multidisciplinary clinical review, we summarise the latest scientific data regarding Long COVID and its impact on children. Special attention is given to diagnostic tests, in order to help the physicians to find potential disease markers and quantify impairment. Specifically, we assess the respiratory, upper airways, cardiac, neurologic and motor and psychological aspects. Finally, we also propose a multidisciplinary clinical approach