Bench assessment of PC-CMVs modes in transport and emergency ventilators under ICU conditions.

Although there has been an increase in bench test evaluation of mechanical ventilators in recent years, a publication gap remains in assessing Pressure Control Continuous Mandatory Ventilation Modes with a set point targeting scheme PC-CMVs. This study evaluates the operational variability in PC-CMVs of eleven transport and emergency ventilators used in ICU units in Brazil during the COVID-19 pandemic. The assessment involved a comprehensive set of test scenarios derived from existing literature and the NBR ISO 80601-2-12:2014 standard.

Central venous pressure waveform analysis during sleep/rest: a novel approach to enhance intensive care unit post-extubation monitoring of extubation failure.

This pilot study aimed to investigate the relation between cardio-respiratory parameters derived from Central Venous Pressure (CVP) waveform and Extubation Failure (EF) in mechanically ventilated ICU patients during post-extubation period. This study also proposes a new methodology for analysing these parameters during rest/sleep periods to try to improve the identification of EF. We conducted a prospective observational study, computing CVP-derived parameters including breathing effort, spectral analyses, and entropy in twenty critically ill patients post-extubation.

Lung Mechanics Over the Century: From Bench to Bedside and Back to Bench.

Lung physiology research advanced significantly over the last 100 years. Respiratory mechanics applied to animal models of lung disease extended the knowledge of the workings of respiratory system. In human research, a better understanding of respiratory mechanics has contributed to development of mechanical ventilators.

Assessment of Regional Ventilation During Recruitment Maneuver by Electrical Impedance Tomography in Dogs.

Background: During protective mechanical ventilation, electrical impedance tomography (EIT) is used to monitor alveolar recruitment maneuvers as well as the distribution of regional ventilation. This technique can infer atelectasis and lung overdistention during mechanical ventilation in anesthetized patients or in the ICU. Changes in lung tissue stretching are evaluated by monitoring the electrical impedance of lung tissue with each respiratory cycle.

Desaturation-Distance Ratio During Submaximal and Maximal Exercise Tests and Its Association With Lung Function Parameters in Patients With Lymphangioleiomyomatosis.

The desaturation-distance ratio (DDR), the ratio of the desaturation area to the distance walked, is a promising, reliable, and simple physiologic tool for functional evaluation in subjects with interstitial lung diseases. Lymphangioleiomyomatosis (LAM) is a rare neoplastic condition frequently associated with exercise impairment. However, DDR has rarely been evaluated in patients with LAM.

Respiratory mechanics during methacholine bolus and continuous infusion protocols in asthma model.

Balb/c mice respiratory mechanics was studied in two intravenous methacholine (MCh) protocols: bolus and continuous infusion. The Constant Phase Model (CPM) was used in this study. The harmonic distortion index (k) was used to assess the respiratory system nonlinearity.

Challenges for the development of alternative low-cost ventilators during COVID-19 pandemic in Brazil.

The COVID-19 pandemic has brought concerns to managers, healthcare professionals, and the general population related to the potential mechanical ventilators' shortage for severely ill patients. In Brazil, there are several initiatives aimed at producing alternative ventilators to cover this gap. To assist the teams that work in these initiatives, we provide a discussion of some basic concepts on physiology and respiratory mechanics, commonly used mechanical ventilation terms, the differences between triggering and cycling, the basic ventilation modes and other relevant aspects, such as mechanisms of ventilator-induced lung injury, respiratory drive, airway heating and humidification, cross-contamination risks, and aerosol dissemination.

Effects of elastic tape on thoracoabdominal mechanics, dyspnea, exercise capacity, and physical activity level in nonobese male subjects with COPD.

Subjects with severe and very severe chronic obstructive pulmonary disease (COPD) present thoracoabdominal asynchrony (TAA) that reduces ventilatory efficiency and exercise capacity. However, no therapeutic intervention has focused on reducing TAA. The purpose of this study was to evaluate the effects of elastic tape (ET) on thoracoabdominal mechanics, dyspnea symptoms, exercise capacity, and physical activity level in nonobese male subjects with severe-to-very severe COPD.

An in vivo image acquisition system for the evaluation of tracheal mechanics in rats.

Mechanical evaluation of tracheal grafts is of great relevance for transplant research. Although there are some publications demonstrating different techniques of tracheal mechanical evaluation, there is still no definitive or preferred protocol available. Here, we present a simple image processing acquisition system that can be used for in vivo experiments.

Author Correction: Low dose of chlorine exposure exacerbates nasal and pulmonary allergic inflammation in mice.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Low dose of chlorine exposure exacerbates nasal and pulmonary allergic inflammation in mice.

Work-exacerbated asthma (WEA) is defined as preexisting asthma that worsens with exposure to irritants [e.g., chlorine (Cl) derivatives] in the workplace.

Mechanical Evaluation of Tracheal Grafts on Different Scales.

Tissue engineered (or bioengineered) tracheas are alternative options under investigation when the resection with end-to-end anastomosis cannot be performed. One approach to develop bioengineered tracheas is a complex process that involves the use of decellularized tissue scaffolds, followed by recellularization in custom-made tracheal bioreactors. Tracheas withstand pressure variations and their biomechanics are of great importance so that they do not collapse during respiration, although there has been no preferred method of mechanical assay of tracheas among several laboratories over the years.

Compensatory lung growth after bilobectomy in emphysematous rats.

Lung volume reduction surgery (LVRS) is an option for emphysematous patients who are awaiting lung transplantation. LVRS reduces nonfunctional portions of lung tissues and favors the compensatory lung growth (CLG) of the remaining lobes. This phenomenon diminishes dyspnea and improves both the respiratory mechanics and quality of life for the patients.

The effects of individually ventilated cages on the respiratory systems of male and female Wistar rats from birth until adulthood.

Objective:: To evaluate the respiratory systems of male and female rats maintained in individually ventilated cages (IVCs) from birth until adulthood.

Methods:: Female Wistar rats were housed in individually ventilated cages or conventional cages (CCs) and mated with male Wistar rats. After birth and weaning, the male offspring were separated from the females and kept in cages of the same type until 12 weeks of age.

Influence of interface and position on upper airway collapsibility assessed by negative expiratory pressure.

Purpose: Negative expiratory pressure (NEP) is a simple technique for the evaluation of upper airway collapsibility in patients with obstructive sleep apnea (OSA). Most studies evaluated NEP using a mouthpiece that may exclude the cephalic portion of the upper airway. We hypothesize that NEP determination is influenced by interface and position.

Upper Airway Collapsibility Assessed by Negative Expiratory Pressure while Awake is Associated with Upper Airway Anatomy.

Study Objectives: There is a growing interest to develop a simple method to characterize the mechanisms leading to upper airway collapse in order to guide treatment options in patients with obstructive sleep apnea (OSA). Critical closing pressure (Pcrit) during sleep is able to predict the anatomical component of OSA. However, Pcrit is a laborious method that is only used for research purposes.

Body Position May Influence Oronasal CPAP Effectiveness to Treat OSA.

CPAP applied by a nasal mask is the gold standard treatment of obstructive sleep apnea. Oronasal masks are an alternative interface that can be used, especially in subjects with predominant oral breathing. However, oronasal masks have higher costs, are associated with larger leaks and higher residual apnea-hypopnea index, and in some cases may be ineffective.

Assessment of the mechanics of a tissue-engineered rat trachea in an image-processing environment.

Objectives: Despite the recent success regarding the transplantation of tissue-engineered airways, the mechanical properties of these grafts are not well understood. Mechanical assessment of a tissue-engineered airway graft before implantation may be used in the future as a predictor of function. The aim of this preliminary work was to develop a noninvasive image-processing environment for the assessment of airway mechanics.

Bronchial responsiveness in an elastase-induced mouse model of emphysema.

Bronchial responsiveness during methacholine (MCh) challenge was analysed in an elastase-induced mouse model of emphysema to explore the magnitude of the response in this model. Swiss mice were intratracheally instilled with saline or elastase (0.3 or 0.

Formaldehyde inhalation reduces respiratory mechanics in a rat model with allergic lung inflammation by altering the nitric oxide/cyclooxygenase-derived products relationship.

Bronchial hyperresponsiveness is a hallmark of asthma and many factors modulate bronchoconstriction episodes. A potential correlation of formaldehyde (FA) inhalation and asthma has been observed; however, the exact role of FA remains controversial. We investigated the effects of FA inhalation on Ovalbumin (OVA) sensitisation using a parameter of respiratory mechanics.

Respiratory inductive plethysmography: a comparative study between isovolume maneuver calibration and qualitative diagnostic calibration in healthy volunteers assessed in different positions.

Objective: To compare two methods of respiratory inductive plethysmography (RIP) calibration in three different positions.

Methods: We evaluated 28 healthy subjects (18 women and 10 men), with a mean age of 25.4 ± 3.

An experimental rat model of ex vivo lung perfusion for the assessment of lungs after prostacyclin administration: inhaled versus parenteral routes.

Objective: To present a model of prostaglandin I2 (PGI2) administration (inhaled vs. parenteral) and to assess the functional performance of the lungs in an ex vivo lung perfusion system.

Methods: Forty Wistar rats were anesthetized and placed on mechanical ventilation followed by median sterno-laparotomy and anticoagulation.