Experimental approaches have been implemented to research the lung damage related-mechanism. These models show in animals pathophysiological events for acute respiratory distress syndrome (ARDS), such as neutrophil activation, reactive oxygen species burst, pulmonary vascular hypertension, exudative edema, and other events associated with organ dysfunction. Moreover, these approaches have not reproduced the clinical features of lung damage. Lung inflammation is a relevant event in the develop of ARDS as component of the host immune response to various stimuli, such as cytokines, antigens and endotoxins. In patients surviving at the local inflammatory states, transition from injury to resolution is an active mechanism regulated by the immuno-inflammatory signaling pathways. Indeed, inflammatory process is regulated by the dynamics of cell populations that migrate to the lung, such as neutrophils and on the other hand, the role of the modulation of transcription factors and reactive oxygen species (ROS) sources, such as nuclear factor kappaB and NADPH oxidase. These experimental animal models reproduce key components of the injury and resolution phases of human ALI/ARDS and provide a methodology to explore mechanisms and potential new therapies.

Transfusion-related acute lung injury (TRALI) is a life-threatening intervention that develops within 6 hours of transfusion of one or more units of blood, and is an important cause of morbidity and mortality resulting from transfusion. It is necessary to dismiss other causes of acute lung injury (ALI), like sepsis, acute cardiogenic edema, acute respiratory distress syndrome (ARDS) or bacterial infection. There are two mechanisms that lead to the development of this syndrome: immune-mediated and no immune- mediated TRALI. A common theme among the experimental TRALI models is the central importance of neutrophils in mediating the early immune response, and lung vascular injury. Central clinical symptoms are dyspnea, tachypnea, tachycardia, cyanosis and pulmonary secretions, altogether with other hemodynamic alterations, such as hypotension and fever. Complementary to these clinical findings, long-term validated animal models for TRALI should allow the determination of the cellular targets for TRALI-inducing alloantibodies as well as delineation of the underlying pathogenic molecular mechanisms, and key molecular mediators of the pathology. Diagnostic criteria have been established and preventive measures have been implemented. These actions have contributed to the reduction in the overallnumber of fatalities. However, TRALI still remains a clinical problem. Any complication suspected of TRALI should immediately be reported.

The normal physiology of conditioning of inspired gases is altered when the patient requires an artificial airway access and an invasive mechanical ventilation (IMV). The endotracheal tube (ETT) removes the natural mechanisms of filtration, humidification and warming of inspired air. Despite the noninvasive ventilation (NIMV) in the upper airways, humidification of inspired gas may not be optimal mainly due to the high flow that is being created by the leakage compensation, among other aspects. Any moisture and heating deficit is compensated by the large airways of the tracheobronchial tree, these are poorly suited for this task, which alters mucociliary function, quality of secretions, and homeostasis gas exchange system. To avoid the occurrence of these events, external devices that provide humidification, heating and filtration have been developed, with different degrees of evidence that support their use.

Hand grip strength values in normal Chilean subjects Background: A low hand grip strength is a prognostic factor both in healthy people and hospitalized subjects. Local normal hand grip strength values are needed to define cutoff points of abnormality. Aim: To measure handgrip strength in Chilean people aged 20 to 70 years and propose normal values for healthy people in this age range. Material and Methods: Handgrip strength was measured using a JAMAR hydraulic dynamometer in 436 males and 465 females aged 20 to 70 years and who were free of disease. They were recruited from waiting rooms in several public and private hospitals and outpatient clinics, under self-evaluation of inclusion criteria. Results: The variability of the handgrip strength in women was smaller in than men. Tables containing handgrip strength values by age and sex and the ranges between three standard deviations were prepared. Conclusions: This study contributes with normal handgrip strength values in Chile to be used for the diagnosis and management of various conditions, such sarcopenia, obesity, oncological patients, Intensive Care Unit acquired weakness (ICU-aw) and weaning of mechanical ventilation.

Noninvasive mechanical ventilation (NIMV) was created for patients who needed noninvasive ventilator support, this procedure decreases the complications associated with the use of endotracheal intubation (ETT). The application of NIMV has acquired major relevance in the last few years in the management of acute respiratory failure (ARF), in patients with hypoxemic and hypercapnic failure. The main advantage of NIMV as compared to invasive mechanical ventilation (IMV) is that it can be used earlier outside intensive care units (ICUs). The evidence strongly supports its use in patients with COPD exacerbation, support in weaning process in chronic obstructive pulmonary disease (COPD) patients, patients with acute cardiogenic pulmonary edema (ACPE), and Immunosuppressed patients. On the other hand, there is poor evidence that supports the use of NIMV in other pathologies such as pneumonia, acute respiratory distress syndrome (ARDS), and during procedures as bronchoscopy, where its use is still controversial because the results of these studies are inconclusive against the decrease in the rate of intubation or mortality.

Physiotherapist in Chile and Respiratory Therapist worldwide are the professionals who are experts in respiratory care, in mechanical ventilation (MV), pathophysiology and connection and disconnection criteria. They should be experts in every aspect of the acute respiratory failure and its management, they and are the ones who in medical units are able to resolve doubts about ventilation and the setting of the ventilator. Noninvasive mechanical ventilation should be the first-line of treatment in acute respiratory failure, and the standard of care in severe exacerbations of chronic obstructive pulmonary disease, acute cardiogenic pulmonary edema, and in immunosuppressed patients with high levels of evidence that support the work of physiotherapist. Exist other considerations where most of the time, physicians and other professionals in the critical units do not take into account when checking the patient ventilator synchrony, such as the appropriate patient selection, ventilator selection, mask selection, mode selection, and the selection of a trained team in NIMV. The physiotherapist needs to evaluate bedside; if patients are properly connected to the ventilator and in a synchronously manner. In Chile, since 2004, the physioterapist are included in the guidelines as a professional resource in the ICU organization, with the same skills and obligations as those described in the literature for respiratory therapists.

Background: Chronic obstructive pulmonary disease (COPD) is a pathology, which leads to an irreversible and progressive reduction of the airflow, usually caused by smoking, but only present in 25% of smokers. Some mechanisms involved in the onset and progression of the disease are local and systemic factors such as inflammation, exacerbated immune response and the appearance of oxidative stress. For all these reasons, the use of oxidative stress parameters as progression markers or even as a way to monitor the response of any kind of non-pharmacological interventions, like the use of pulmonary rehabilitation (PR), is feasible. Aims: The study aims to determine markers of oxidative stress levels in plasma and erythrocytes in patients with COPD through the application of a PR protocol. Methods: The study included 25 patients diagnosed with COPD according to the GOLD criteria with a medical indication of PR and attendance at the gym in San José Hospital, Santiago, Chile. Blood samples were obtained before the start of the protocol, in the 10th session, and at the end of the protocol (20th session). These samples were stored for oxidative stress determinations: FRAP (ferric reducing ability of plasma), F2-isoprostanes, reduced (GSH)/oxidized (GSSG) ratio and antioxidant enzyme activity in the erythrocyte. In all stages, associations between events and clinical parameters in patients have been observed. The clinical parameters assessed were the six-minute walking test (6MWT), maximal inspiratory and expiratory pressure, the BODE index and Saint George’s respiratory questionnaire, which includes quality of life. Results: The intracellular and extracellular capacity (GSH/GSSG and FRAP) in patients in PR at the 10th session were 53.1 and 34% higher than basal values, respectively. Only the GSH/GSSG ratio was 38.2% lower at the 20th session, related in part with higher plasma and erythrocyte lipid peroxidation at baseline. This could be due to the high concentration of reactive oxygen species in the first sessions, which has been reported in the literature as the acute effect of controlled exercise. Blood lipid peroxidation was 43.34 and 58.34% lower at the 10th and 20th sessions, respectively, demonstrating the improvements in the oxidative parameters with long-term exercise. With respect to oxidative enzyme activity, superoxide dismutase and catalase showed higher values of activity at the 10th and 20th sessions compared to the baseline. In the clinical parameters of the PR, significant changes were found in the BODE index and Saint George’s questionnaire, with these results being associated with a less predictive mortality score and a better understanding of the disease. This may be because the patients achieved longer distances in the 6MWT and better understood the disease at the end of the PR. Conclusion: The goal of this study was to contribute to the pathophysiological basis for further research on COPD patients, a disease of high prevalence in Chile. This study could support the basis for non-pharmacological strategies such a PR.