In vitro and in vivo evaluation of a new active heat moisture exchanger.

INTRODUCTION: In order to improve the efficiency of heat moisture exchangers (HMEs), new hybrid humidifiers (active HMEs) that add water and heat to HMEs have been developed. In this study we evaluated the efficiency, both in vitro and in vivo, of a new active HME (the Performer; StarMed, Mirandola, Italy) as compared with that of existing HMEs (Hygroster and Hygrobac; Mallinckrodt, Mirandola, Italy). METHODS: We tested the efficiency by measuring the temperature and absolute humidity (AH) in vitro using a test lung ventilated at three levels of minute ventilation (5, 10 and 15 l/min) and at two tidal volumes (0.5 and 1 l), and in vivo in 42 patients with acute lung injury (arterial oxygen tension/fractional inspired oxygen ratio 283 +/- 72 mmHg). We also evaluated the efficiency in vivo after 12 hours. RESULTS: In vitro, passive Performer and Hygrobac had higher airway temperature and AH (29.2 +/- 0.7 degrees C and 29.2 +/- 0.5 degrees C, [P < 0.05]; AH: 28.9 +/- 1.6 mgH2O/l and 28.1 +/- 0.8 mgH2O/l, [P < 0.05]) than did Hygroster (airway temperature: 28.1 +/- 0.3 degrees C [P < 0.05]; AH: 27 +/- 1.2 mgH2O/l [P < 0.05]). Both devices suffered a loss of efficiency at the highest minute ventilation and tidal volume, and at the lowest minute ventilation. Active Performer had higher airway temperature and AH (31.9 +/- 0.3 degrees C and 34.3 +/- 0.6 mgH2O/l; [P < 0.05]) than did Hygrobac and Hygroster, and was not influenced by minute ventilation or tidal volume. In vivo, the efficiency of passive Performer was similar to that of Hygrobac but better than Hygroster, whereas Active Performer was better than both. The active Performer exhibited good efficiency when used for up to 12 hours in vivo. CONCLUSION: This study showed that active Performer may provide adequate conditioning of inspired gases, both as a passive and as an active device

Recent advances in cardiorespiratory monitoring in acute respiratory distress syndrome patients

Background: Recent advances on cardiorespiratory monitoring applied in ARDS patients undergoing invasive mechanical ventilation and noninvasive ventilatory support are available in the literature and may have potential prognostic implication in ARDS treatment. Main body: The measurement of oxygen saturation by pulse oximetry is a valid, low-cost, noninvasive alternative for assessing arterial oxygenation. Caution must be taken in patients with darker skin pigmentation, who may experience a greater incidence of occult hypoxemia. Dead space surrogates, which are easy to calculate, have important prognostic implications. The mechanical power, which can be automatically computed by intensive care ventilators, is an important parameter correlated with ventilator-induced lung injury and outcome. In patients undergoing noninvasive ventilatory support, the use of esophageal pressure can measure inspiratory effort, avoiding possible delays in endotracheal intubation. Fluid responsiveness can also be evaluated using dynamic indices in patients ventilated at low tidal volumes (&lt; 8&nbsp;mL/kg). In patients ventilated at high levels of positive end expiratory pressure (PEEP), the PEEP test represents a valid alternative to passive leg raising. There is growing evidence on alternative parameters for evaluating fluid responsiveness, such as central venous oxygen saturation variations, inferior vena cava diameter variations and capillary refill time. Conclusion: Careful cardiorespiratory monitoring in patients affected by ARDS is crucial to improve prognosis and to tailor treatment via mechanical ventilatory support

Mucins and Asthma : Are We Headed to the Revolutionary Road?

Mucus represents the first line of defense of our respiratory tract and mucociliary clearance is essential for maintaining the homeostasis of airway epithelium. The latter mechanisms are altered in asthma and mucus plugging of proximal and distal airways is the main cause of death in cases of fatal asthma. Starting from the influential review performed by Luke R. Bonser and David J. Erle in 2017, we discuss the latest evidence in terms of mucins regulation and potential treatment of mucus hypersecretion and tissue remodeling in severe asthma

Endothelial-Mesenchymal Transition in COVID-19 lung lesions

Sars-Cov-2 infection is still a healthcare emergency and acute respiratory distress failure with Diffuse Alveolar Damage (DAD) features is the main causes of patients’ death. Pathogenic mechanisms of the disease are not clear yet, but new insights are necessary to improve therapeutic management, to prevent fatal irreversible multi-organ damage and to adequately follow up those patients who survive. Here we investigated, by histochemistry and immunohistochemistry, a wide number of mapped lung specimens taken from whole body autopsies of 7 patients dead of COVID-19 disease. Our data confirm morphological data of other authors, and enlarge recent reports of the literature suggesting that Endothelial–Mesenchymal Transition might be central to COVID-19 lung fibrosing lesions. Furthermore, based upon recent acquisition of new roles in immunity and vascular pathology of the CD31 molecule, we hypothesize that this molecule might be important in the development and treatment of COVID-19 pulmonary lesions. These preliminary findings need further investigations to shed light on the complexity of Sars-Cov-2 disease

Respiratory challenges and ventilatory management in different types of acute brain-injured patients

Acute brain injury (ABI) covers various clinical entities that may require invasive mechanical ventilation (MV) in the intensive care unit (ICU). The goal of MV, which is to protect the lung and the brain from further injury, may be difficult to achieve in the most severe forms of lung or brain injury. This narrative review aims to address the respiratory issues and ventilator management, specific to ABI patients in the ICU

Mobile Extracorporeal Membrane Oxygenation Teams for Organ Donation After Circulatory Death

The shortage of available organ donors is a significant problem worldwide, and various efforts have been carried out to avoid the loss of potential organ donors. Among them, organ donation from cardiocirculatory deceased donors (DCD), in which withdrawal of life-sustaining therapies is ongoing (Maastricht type III donors), is one emerging strategy. Thanks to the latest advances in transplantation and organ preservation, such as normothermic regional perfusion (NRP), ex vivo perfusion techniques, and good organization and communication among prehospital care providers, emergency departments, intensive care units, and transplantation units, DCD is rapidly increasing; it's estimated that it will increase the number of donations of lungs and splanchnic organs by more than 40%. Although Maastricht type II DCD requires a 24/7 available experienced extra corporeal membrane oxygenation (ECMO) team in the institution, Maastricht DCD type III could be organized in secondary care and spoke hospitals without in loco ECMO facilities for NRP. This article analyses a potential mobile team organization based on the hub-and-spoke model, which already exists and functions in Italy, by estimating the dimension of the controlled DCD phenomenon in Italy, coordination requirements, costs, personnel training, and education, and reporting a single center experience in Milan, Italy