Pulmonary consequences of experimentally induced stroke: differences between global and focal cerebral ischemia.

Introduction: Cerebral ischemia leads to multiple organ dysfunctions, with the lungs among the most severely affected. Although adverse pulmonary consequences contribute significantly to reduced life expectancy after stroke, the impact of global or focal cerebral ischemia on respiratory mechanical parameters remains poorly understood.

Methods: Rats were randomly assigned to undergo surgery to induce permanent global cerebral ischemia (2VO) or focal cerebral ischemia (MCAO), or to receive a sham operation (SHAM).

Relationships between capnogram parameters by mainstream and sidestream techniques at different breathing frequencies.

Capnography, routinely used in operating rooms and intensive care units, reveals essential information on lung ventilation and ventilation-perfusion matching. Mainstream capnography directly measures CO in the breathing circuit for accurate analysis and is considered a reference technique. Sidestream capnography, however, analyzes gas away from the patient leading to potentially less accurate measures.

Variable positive end-expiratory pressure in an experimental model of acute respiratory distress syndrome: an advanced ventilation modality.

Background: Introducing variability in tidal volume, ventilatory frequency, or both is beneficial during mechanical ventilation in acute respiratory distress syndrome (ARDS). We investigated whether applying cycle-by-cycle variability in the positive end-expiratory pressure (PEEP) exerts beneficial effect on lung function in a model of ARDS.

Methods: Rabbits with lung injury were randomly allocated to receive mechanical ventilation for 6 h by applying a pressure-controlled mode with constant PEEP of 7 cm HO (PC group: =6) or variable PEEP (VEEP) with a coefficient of variation of 21.

Benefits of intratracheal and extrathoracic high-frequency percussive ventilation in a model of capnoperitoneum.

Abdominal inflation with CO is used to facilitate laparoscopic surgeries, however, providing adequate mechanical ventilation in this scenario is of major importance during anesthesia management. We characterized high-frequency percussive ventilation (HFPV) in protecting from the gas exchange and respiratory mechanical impairments during capnoperitoneum. In addition, we aimed to assess the difference between conventional pressure-controlled mechanical ventilation (CMV) and HFPV modalities generating the high-frequency signal intratracheally (HFPVi) or extrathoracally (HFPVe).

Changes in lung mechanics and ventilation-perfusion match: comparison of pulmonary air- and thromboembolism in rats.

Background: Pulmonary air embolism (AE) and thromboembolism lead to severe ventilation-perfusion defects. The spatial distribution of pulmonary perfusion dysfunctions differs substantially in the two pulmonary embolism pathologies, and the effects on respiratory mechanics, gas exchange, and ventilation-perfusion match have not been compared within a study. Therefore, we compared changes in indices reflecting airway and respiratory tissue mechanics, gas exchange, and capnography when pulmonary embolism was induced by venous injection of air as a model of gas embolism or by clamping the main pulmonary artery to mimic severe thromboembolism.

Respiratory effects of pressure support ventilation in spontaneously breathing patients under anaesthesia: Randomised controlled trial.

Background: Lung volume loss is a major risk factor for postoperative respiratory complications after general anaesthesia and mechanical ventilation. We hypothesise that spontaneous breathing without pressure support may enhance the risk for atelectasis development. Therefore, we aimed at characterising whether pressure support prevents changes in lung function in patients breathing spontaneously through laryngeal mask airway.

Comparison of the respiratory effects of commonly utilized general anaesthesia regimes in male Sprague-Dawley rats.

Respiratory parameters in experimental animals are often characterised under general anaesthesia. However, anaesthesia regimes may alter the functional and mechanical properties of the respiratory system. While most anaesthesia regimes have been shown to affect the respiratory system, the effects of general anaesthesia protocols commonly used in animal models on lung function have not been systematically compared.

Lung recruitment by continuous negative extra-thoracic pressure support following one-lung ventilation: an experimental study.

Lung recruitment maneuvers following one-lung ventilation (OLV) increase the risk for the development of acute lung injury. The application of continuous negative extrathoracic pressure (CNEP) is gaining interest both in intubated and non-intubated patients. However, there is still a lack of knowledge on the ability of CNEP support to recruit whole lung atelectasis following OLV.

Fractal dimension of pulmonary gas and blood distribution assessed by synchrotron K-edge subtraction imaging: effect of bronchoconstriction.

We analyzed the fractal dimension (Df) of lung gas and blood distribution imaged with synchrotron radiation K-edge subtraction (KES), in six anesthetized adult New Zealand White rabbits. KES imaging was performed in upright position during stable Xe gas (64% in O) inhalation and iodine infusion (Iomeron, 350 mg/mL), respectively, at baseline and after induced bronchoconstriction by aerosolized methacholine (125 mg/mL, 90 s) and bronchodilator (salbutamol, 10 mg/mL, 90 s) inhalation, at two axial image levels. Lung Xe and iodine images were segmented, and maps of regional lung gas and blood fractions were computed.

Expiratory high-frequency percussive ventilation: a novel concept for improving gas exchange.

Background: Although high-frequency percussive ventilation (HFPV) improves gas exchange, concerns remain about tissue overdistension caused by the oscillations and consequent lung damage. We compared a modified percussive ventilation modality created by superimposing high-frequency oscillations to the conventional ventilation waveform during expiration only (eHFPV) with conventional mechanical ventilation (CMV) and standard HFPV.

Methods: Hypoxia and hypercapnia were induced by decreasing the frequency of CMV in New Zealand White rabbits (n = 10).

Flow-controlled ventilation maintains gas exchange and lung aeration in a pediatric model of healthy and injured lungs: A randomized cross-over experimental study.

Flow-controlled ventilation (FCV) is characterized by a constant flow to generate active inspiration and expiration. While the benefit of FCV on gas exchange has been demonstrated in preclinical and clinical studies with adults, the value of this modality for a pediatric population remains unknown. Thus, we aimed at observing the effects of FCV as compared to pressure-regulated volume control (PRVC) ventilation on lung mechanics, gas exchange and lung aeration before and after surfactant depletion in a pediatric model.

Seasonal changes in proportion of cardiac surgeries associated with diabetes, smoking and elderly age.

Background: Seasonal variations in the ambient temperature may affect the exacerbation of cardiovascular diseases. Our primary objective was to evaluate the seasonality of the monthly proportion of cardiac surgeries associated with diabetes, smoking and/or elderly age at a tertiary-care university hospital in East-Central Europe with a temperate climate zone. As a secondary objective, we also assessed whether additional factors affecting small blood vessels (smoking, aging, obesity) modulate the seasonal variability of diabetes.

Effect of body position on the redistribution of regional lung aeration during invasive and non-invasive ventilation of COVID-19 patients.

Severe COVID-19-related acute respiratory distress syndrome (C-ARDS) requires mechanical ventilation. While this intervention is often performed in the prone position to improve oxygenation, the underlying mechanisms responsible for the improvement in respiratory function during invasive ventilation and awake prone positioning in C-ARDS have not yet been elucidated. In this prospective observational trial, we evaluated the respiratory function of C-ARDS patients while in the supine and prone positions during invasive (n = 13) or non-invasive ventilation (n = 15).

Exaggerated Ventilator-Induced Lung Injury in an Animal Model of Type 2 Diabetes Mellitus: A Randomized Experimental Study.

Although ventilator-induced lung injury (VILI) often develops after prolonged mechanical ventilation in normal lungs, pulmonary disorders may aggravate the development of adverse symptoms. VILI exaggeration can be anticipated in type 2 diabetes mellitus (T2DM) due to its adverse pulmonary consequences. Therefore, we determined whether T2DM modulates VILI and evaluated how T2DM therapy affects adverse pulmonary changes.

Invasive and non-invasive assessment of macro- and micro-circulatory effects of vasopressors during sevoflurane anesthesia in a pediatric experimental model: A randomized trial.

Background: While non-invasive assessment of macro- and micro-circulation has the promise to optimize anesthesia management, evidence is lacking for the relationship between invasive and non-invasive measurements of cardiac output and microcirculatory indices.

Aims: We aimed to compare the abilities of non-invasive techniques to detect changes in macro- and micro-circulation following deep anesthesia and subsequent restoration of the compromised hemodynamic by routinely used vasopressors in a randomized experimental study.

Methods: A 20%-25% drop in mean arterial pressure was induced by sevoflurane in anesthetized mechanically ventilated just-weaned piglets (n = 12) prior to the administration of vasopressors in random order (dopamine, ephedrine, noradrenaline, and phenylephrine).

Sevoflurane and Hypercapnia Blunt the Physiological Variability of Spontaneous Breathing: A Comparative Interventional Study.

Although spontaneous breathing is known to exhibit substantial physiological fluctuation that contributes to alveolar recruitment, changes in the variability of the respiratory pattern following inhalation of carbon dioxide (CO) and volatile anesthetics have not been characterized. Therefore, we aimed at comparing the indices of breathing variability under wakefulness, sleep, hypercapnia and sedative and anesthetic concentrations of sevoflurane. Spontaneous breathing pattern was recorded on two consecutive days in six rabbits using open whole-body plethysmography under wakefulness and spontaneous sleep and following inhalation of 5% CO, 2% sevoflurane (0.

Lung and chest wall mechanical properties in metformin-treated and untreated models of type 2 diabetes.

The adverse respiratory consequences of type 2 diabetes mellitus (T2DM) may reflect compromised lung function and/or alterations of the chest wall because of skeletal muscle stiffening. We assessed the separate contributions of these compartments to respiratory complications in diabetes and explored the effects of metformin on respiratory abnormalities. Experiments were performed in untreated rats (control, = 7), high-fat diet-fed rats receiving streptozotocin (T2DM, = 7), and metformin-treated diabetic rats (MET, = 6).

Physiologically variable ventilation prevents lung function deterioration in a model of pulmonary fibrosis.

Positive pressure ventilation exerts an increased stress and strain in the presence of pulmonary fibrosis. Thus, ventilation strategies that avoid high pressures while maintaining lung aeration are of paramount importance. Although physiologically variable ventilation (PVV) has proven beneficial in various models of pulmonary disease, its potential advantages in pulmonary fibrosis have not been investigated.

[Respiratory consequences of obesity and diabetes].

Unlabelled: Összefoglaló. Bevezetés: A cukorbetegségben nő a simaizmok tónusa, és megváltozik az elasztin és a kollagén szerkezete. Mivel a tüdőszövetben ezek a strukturális elemek meghatározóak, a cukorbetegség várhatóan módosítja a légutak és a tüdőszövet mechanikai és funkcionális viselkedését.

Dopamine Reverses Lung Function Deterioration After Cardiopulmonary Bypass Without Affecting Gas Exchange.

Objective: To investigate the effects of dopamine on the adverse pulmonary changes after cardiopulmonary bypass.

Design: A prospective, nonrandomized clinical investigation.

Setting: A university hospital.

Benefit of Physiologically Variable Over Pressure-Controlled Ventilation in a Model of Chronic Obstructive Pulmonary Disease: A Randomized Study.

Introduction: The advantages of physiologically variable ventilation (PVV) based on a spontaneous breathing pattern have been demonstrated in several respiratory conditions. However, its potential benefits in chronic obstructive pulmonary disease (COPD) have not yet been characterized. We used an experimental model of COPD to compare respiratory function outcomes after 6 h of PVV versus conventional pressure-controlled ventilation (PCV).

Use of capnography to verify emergency ventilator sharing in the COVID-19 era.

Exacerbation of COVID-19 pandemic may lead to acute shortage of ventilators, which may require shared use of ventilator as a lifesaving concept. Two model lungs were ventilated with one ventilator to i) test the adequacy of individual tidal volumes via capnography, ii) assess cross-breathing between lungs, and iii) offer a simulation-based algorithm for ensuring equal tidal volumes. Ventilation asymmetry was induced by placing rubber band around one model lung, and the uneven distribution of tidal volumes (VT) was counterbalanced by elevating airflow resistance (HR) contralaterally.