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.

Individual benefit in heart sparing during DIBH-supported left breast radiotherapy.

Introduction: Deep-inspirational breath hold (DIBH) is an option for heart protection in breast radiotherapy; we intended to study its individual benefit.

Materials And Methods: 3DCRT treatment planning was performed in a cohort of 103 patients receiving radiotherapy of the whole breast (WBI)/chest wall (CWI) ± nodal regions (NI) both under DIBH and free breathing (FB) in the supine position, and in the WBI only cases prone (n = 45) position, too. A series of patient-related and heart dosimetry parameters were analyzed.

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.

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.

Benefit of Flow-Controlled Over Pressure-Regulated Volume Control Mode During One-Lung Ventilation: A Randomized Experimental Crossover Study.

Background: Application of a ventilation modality that ensures adequate gas exchange during one-lung ventilation (OLV) without inducing lung injury is of paramount importance. Due to its beneficial effects on respiratory mechanics and gas exchange, flow-controlled ventilation (FCV) may be considered as a protective alternative mode of traditional pressure- or volume-controlled ventilation during OLV. We investigated whether this new modality provides benefits compared with conventional ventilation modality for OLV.

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).

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.

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).

Size of the Carotid Body in Patients with Cardiovascular and Respiratory Diseases Measured by Computed Tomography Angiography: A Case-Control Study.

Objectives: Carotid bodies (CBs) play an important role in regulating sympathetic nervous system activity. Thus, they are likely to be enlarged in patients with certain cardiovascular and respiratory diseases. The aim of this case-control study was to verify this hypothesis using computed tomography angiography (CTA).

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.

Characterization of technical skill progress in a standardized rabbit model for training in laparoscopic duodenal atresia repair.

Background: Laboratory skills training is an essential step before conducting minimally invasive surgery in clinical practice. Our main aim was to develop an animal model for training in clinically highly challenging laparoscopic duodenal atresia repair that could be useful in establishing a minimum number of repetitions to indicate safe performance of similar interventions on humans.

Materials And Methods: A rabbit model of laparoscopic duodenum atresia surgery involving a diamond-shaped duodeno-duodenostomy was designed.

Effect of Permissive Mild Hypercapnia on Cerebral Vasoreactivity in Infants: A Randomized Controlled Crossover Trial.

Background: Mechanical ventilation interferes with cerebral perfusion via changes in intrathoracic pressure and/or as a consequence of alterations in CO2. Cerebral vascular vasoreactivity is dependent on CO2, and hypocapnia can potentially lead to vasoconstriction and subsequent decrease in cerebral blood flow. Thus, we aimed at characterizing whether protective ventilation with mild permissive hypercapnia improves cerebral perfusion in infants.

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.

Obesity and diabetes: similar respiratory mechanical but different gas exchange defects.

Diabetes mellitus increases smooth muscle tone and causes tissue remodeling, affecting elastin and collagen. Although the lung is dominated by these elements, diabetes is expected to modify the airway function and respiratory tissue mechanics. Therefore, we characterized the respiratory function in patients with diabetes with and without associated obesity.

Physiologically variable ventilation reduces regional lung inflammation in a pediatric model of acute respiratory distress syndrome.

Background: Benefits of variable mechanical ventilation based on the physiological breathing pattern have been observed both in healthy and injured lungs. These benefits have not been characterized in pediatric models and the effect of this ventilation mode on regional distribution of lung inflammation also remains controversial. Here, we compare structural, molecular and functional outcomes reflecting regional inflammation between PVV and conventional pressure-controlled ventilation (PCV) in a pediatric model of healthy lungs and acute respiratory distress syndrome (ARDS).

Determination of adequate positive end-expiratory pressure level required for carbon dioxide homeostasis in an animal model of infant laparoscopy.

Background: Capnoperitoneum provides a ventilatory challenge due to reduction in end-expiratory lung volume and peritoneal carbon dioxide absorption in both children and adults. The primary aim of this controlled interventional trial was to determine the positive end-expiratory pressure (PEEP) level needed to ensure for adequate carbon dioxide clearance and preservation of carbon dioxide homeostasis in an experimental model of infant laparoscopy. The secondary aim was to evaluate potential effects on cardiac output of PEEP and abdominal pressure level variations in the same setting.

End-expiratory lung volume assessment using helium and carbon dioxide in an experimental model of pediatric capnoperitoneum.

Background: Capnoperitoneum during laparoscopy leads to cranial shift of the diaphragm, loss in lung volume, and risk of impaired gas exchange. Infants are susceptible to these changes and bedside assessment of lung volume during laparoscopy might assist with optimizing the ventilation. Thus, the primary aim was to investigate the monitoring value of a continuous end-expiratory lung volume (EELV) assessment method based on CO dynamics ( ) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELV ).

Lung volume dependence of respiratory function in rodent models of diabetes mellitus.

Background: Diabetes mellitus causes the deterioration of smooth muscle cells and interstitial matrix proteins, including collagen. Collagen and smooth muscle cells are abundant in the lungs, but the effect of diabetes on airway function and viscoelastic respiratory tissue mechanics has not been characterized. This study investigated the impact of diabetes on respiratory function, bronchial responsiveness, and gas exchange parameters.

Reversing Cholinergic Bronchoconstriction by Common Inotropic Agents: A Randomized Experimental Trial on Isolated Perfused Rat Lungs.

Background: The ability of inotropic agents to alter airway reactivity and lung tissue mechanics has not been compared in a well-controlled experimental model. Therefore, we compared the potential to alter lung tissue viscoelasticity and bronchodilator effects of commonly used inotropic agents in an isolated perfused rat lung model.

Methods: After achieving steady state lung perfusion, sustained bronchoconstriction was induced by acetylcholine (ACh).

Variable Ventilation Is Equally Effective as Conventional Pressure Control Ventilation for Optimizing Lung Function in a Rabbit Model of ARDS.

Background: Introducing mathematically derived variability (MVV) into the otherwise monotonous conventional mechanical ventilation has been suggested to improve lung recruitment and gas exchange. Although the application of a ventilation pattern based on variations in physiological breathing (PVV) is beneficial for healthy lungs, its value in the presence of acute respiratory distress syndrome (ARDS) has not been characterized. We therefore aimed at comparing conventional pressure-controlled ventilation with (PCS) or without regular sighs (PCV) to MVV and PVV at two levels of positive end-expiratory pressure (PEEP) in a model of severe ARDS.

Effect of PEEP and I:E ratio on cerebral oxygenation in ARDS: an experimental study in anesthetized rabbit.

Background: Although PEEP and inversed I:E ratio have been shown to improve gas exchange in ARDS, both can adversely affect systemic hemodynamics and cerebral perfusion. The goal of this study was to assess how changes in PEEP and I:E ratio affect systemic and cerebral oxygenation and perfusion in normal and injured lung.

Methods: Eight anesthetized Chinchilla-Bastard rabbits were ventilated at baseline with pressure-regulated volume control mode, V = 6 ml/kg, PEEP = 6 cmHO, FIO = 0.

Different contributions from lungs and chest wall to respiratory mechanics in mice, rats, and rabbits.

Changes in lung mechanics are frequently inferred from intact-chest measures of total respiratory system mechanics without consideration of the chest wall contribution. The participation of lungs and chest wall in respiratory mechanics has not been evaluated systematically in small animals commonly used in respiratory research. Thus, we compared these contributions in intact-chest mice, rats, and rabbits and further characterized the influence of positive end-expiratory pressure (PEEP).

Feasibility of forced oscillatory assessment of respiratory mechanics across a laryngeal mask airway in rabbits.

Objectives: The forced oscillation technique (FOT) is the method of choice for assessment of respiratory tissue mechanics. A laryngeal mask airway (LMA) is increasingly used to secure the airways in subjects under sedation or general anesthesia. While FOT is routinely performed using an endotracheal tube (ETT), the accuracy of information about airway and tissue mechanics obtained with FOT using a LMA has not been characterized.