lung mechanics
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2022 ◽  
Vol 15 ◽  
pp. 1179173X2110696
Author(s):  
Panagis Galiatsatos ◽  
Princess Ekpo ◽  
Raiza Schreiber ◽  
Lindsay Barker ◽  
Pali Shah

Background Smoking behavior includes mechanisms taken on by persons to adjust for certain characteristic changes of cigarettes. However, as lung function declines due to lung-specific diseases, it is unclear how mechanical smoking behavior changes affect persons who smoke. We review two cases of patients who stopped smoking prior to and then subsequently resumed smoking after lung transplantation. Methods A retrospective review of two patients who were recipients of lung transplantation and sustained from cigarette usage prior to transplantation. Results Patient A was a 54-year-old woman who received a double lung transplant secondary to chronic obstructive pulmonary disease (COPD) in October 2017. She had stopped smoking cigarettes in July 2015 (FEV1 .56 L). Patient B was a 40-year-old man who received a double lung transplantation due to sarcoidosis in January 2015. He stopped smoking cigarettes in February 2012 (FEV1 1.15 L). Post-transplant, Patient A resumed smoking on March 2018 where her FEV1 was at 2.12 L (5 months post-transplantation), and Patient B resumed smoking in April 2017 where his FEV1 was 2.37 L (26 months post-transplantation). Conclusion We report on two patients who resumed smoking after lung transplantation. While variations of smoking mechanics have been identified as a function of nicotine yield and type of cigarette, it lung mechanics may play a role in active smoking as well. Therefore, proper screening for tobacco usage post-lung transplantation should be considered a priority in order to preserve transplanted lungs.


2022 ◽  
pp. 66-87
Author(s):  
Jamie L. Sparling ◽  
Marcos F. Vidal Melo
Keyword(s):  

Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 112
Author(s):  
Jonathan M. Preuss ◽  
Ute Burret ◽  
Michael Gröger ◽  
Sandra Kress ◽  
Angelika Scheuerle ◽  
...  

We previously showed that attenuated lung injury after hemorrhagic shock (HS) coincided with enhanced levels of the glucocorticoid (GC) receptor (GR) in lung tissue of swine. Here, we investigated the effects of impaired GR signaling on the lung during resuscitated HS using a dysfunctional GR mouse model (GRdim/dim). In a mouse intensive care unit, HS led to impaired lung mechanics and aggravated lung inflammation in GRdim/dim mice compared to wildtype mice (GR+/+). After HS, high levels of the pro-inflammatory and pro-apoptotic transcription factor STAT1/pSTAT1 were found in lung samples from GRdim/dim mice. Lungs of GRdim/dim mice revealed apoptosis, most likely as consequence of reduced expression of the lung-protective Angpt1 compared to GR+/+ after HS. RNA-sequencing revealed increased expression of pro-apoptotic and cytokine-signaling associated genes in lung tissue of GRdim/dim mice. Furthermore, high levels of pro-inflammatory cytokines and iNOS were found in lungs of GRdim/dim mice. Our results indicate impaired repression of STAT1/pSTAT1 due to dysfunctional GR signaling in GRdim/dim mice, which leads to increased inflammation and apoptosis in the lungs. These data highlight the crucial role of functional GR signaling to attenuate HS-induced lung damage.


2021 ◽  
Vol 38 (1) ◽  
pp. 64-71
Author(s):  
Dalia Ahmed El Sayed El Hefny ◽  
Mohamed Ibrahim Mohamed ◽  
Shahira Ahmed Yousef El-Metainy ◽  
Mohamed Moustafa Ibrahim Abdelaal ◽  
Yasser Mohamed Osman

2021 ◽  
Vol 12 ◽  
Author(s):  
Fernando Suárez-Sipmann ◽  
Jesús Villar ◽  
Carlos Ferrando ◽  
Juan A. Sánchez-Giralt ◽  
Gerardo Tusman

Mechanical ventilation (MV) is a lifesaving supportive intervention in the management of acute respiratory distress syndrome (ARDS), buying time while the primary precipitating cause is being corrected. However, MV can contribute to a worsening of the primary lung injury, known as ventilation-induced lung injury (VILI), which could have an important impact on outcome. The ARDS lung is characterized by diffuse and heterogeneous lung damage and is particularly prone to suffer the consequences of an excessive mechanical stress imposed by higher airway pressures and volumes during MV. Of major concern is cyclic overdistension, affecting those lung segments receiving a proportionally higher tidal volume in an overall reduced lung volume. Theoretically, healthier lung regions are submitted to a larger stress and cyclic deformation and thus at high risk for developing VILI. Clinicians have difficulties in detecting VILI, particularly cyclic overdistension at the bedside, since routine monitoring of gas exchange and lung mechanics are relatively insensitive to this mechanism of VILI. Expired CO2 kinetics integrates relevant pathophysiological information of high interest for monitoring. CO2 is produced by cell metabolism in large daily quantities. After diffusing to tissue capillaries, CO2 is transported first by the venous and then by pulmonary circulation to the lung. Thereafter diffusing from capillaries to lung alveoli, it is finally convectively transported by lung ventilation for its elimination to the atmosphere. Modern readily clinically available sensor technology integrates information related to pulmonary ventilation, perfusion, and gas exchange from the single analysis of expired CO2 kinetics measured at the airway opening. Current volumetric capnography (VCap), the representation of the volume of expired CO2 in one single breath, informs about pulmonary perfusion, end-expiratory lung volume, dead space, and pulmonary ventilation inhomogeneities, all intimately related to cyclic overdistension during MV. Additionally, the recently described capnodynamic method provides the possibility to continuously measure the end-expiratory lung volume and effective pulmonary blood flow. All this information is accessed non-invasively and breath-by-breath helping clinicians to personalize ventilatory settings at the bedside and minimize overdistension and cyclic deformation of lung tissue.


2021 ◽  
Vol 8 (12) ◽  
pp. 222
Author(s):  
Nur Sa’adah Muhamad Sauki ◽  
Nor Salwa Damanhuri ◽  
Nor Azlan Othman ◽  
Belinda Chong Chiew Meng ◽  
Yeong Shiong Chiew ◽  
...  

Respiratory system modelling can assist clinicians in making clinical decisions during mechanical ventilation (MV) management in intensive care. However, there are some cases where the MV patients produce asynchronous breathing (asynchrony events) due to the spontaneous breathing (SB) effort even though they are fully sedated. Currently, most of the developed models are only suitable for fully sedated patients, which means they cannot be implemented for patients who produce asynchrony in their breathing. This leads to an incorrect measurement of the actual underlying mechanics in these patients. As a result, there is a need to develop a model that can detect asynchrony in real-time and at the bedside throughout the ventilated days. This paper demonstrates the asynchronous event detection of MV patients in the ICU of a hospital by applying a developed extended time-varying elastance model. Data from 10 mechanically ventilated respiratory failure patients admitted at the International Islamic University Malaysia (IIUM) Hospital were collected. The results showed that the model-based technique precisely detected asynchrony events (AEs) throughout the ventilation days. The patients showed an increase in AEs during the ventilation period within the same ventilation mode. SIMV mode produced much higher asynchrony compared to SPONT mode (p < 0.05). The link between AEs and the lung elastance (AUC Edrs) was also investigated. It was found that when the AEs increased, the AUC Edrs decreased and vice versa based on the results obtained in this research. The information of AEs and AUC Edrs provides the true underlying lung mechanics of the MV patients. Hence, this model-based method is capable of detecting the AEs in fully sedated MV patients and providing information that can potentially guide clinicians in selecting the optimal ventilation mode of MV, allowing for precise monitoring of respiratory mechanics in MV patients.


2021 ◽  
pp. S195-S208
Author(s):  
A CALKOVSKA ◽  
M KOLOMAZNIK ◽  
V CALKOVSKY

In this review, we discuss the role of pulmonary surfactant in the host defense against respiratory pathogens, including novel coronavirus SARS-CoV-2. In the lower respiratory system, the virus uses angiotensin-converting enzyme 2 (ACE2) receptor in conjunction with serine protease TMPRSS2, expressed by alveolar type II (ATII) cells as one of the SARS-CoV-2 target cells, to enter. ATII cells are the main source of surfactant. After their infection and the resulting damage, the consequences may be severe and may include injury to the alveolar-capillary barrier, lung edema, inflammation, ineffective gas exchange, impaired lung mechanics and reduced oxygenation, which resembles acute respiratory distress syndrome (ARDS) of other etiology. The aim of this review is to highlight the key role of ATII cells and reduced surfactant in the pathogenesis of the respiratory form of COVID-19 and to emphasize the rational basis for exogenous surfactant therapy in COVID-19 ARDS patients.


Author(s):  
Alison Nicole Abele ◽  
Elizabeth S Taglauer ◽  
Maricar Almeda ◽  
Noah Wilson ◽  
Abigail Abikoye ◽  
...  

Background: Antenatal stressors such as chorioamnionitis (CA) increase the risk for bronchopulmonary dysplasia (BPD). Studies have shown that experimental BPD can be ameliorated by postnatal treatment with mesenchymal stromal cell-derived extracellular vesicles (MEx). However, the antenatal efficacy of MEx to prevent BPD is unknown. Objective: To determine whether antenatal MEx therapy attenuates intrauterine inflammation and preserves lung growth in a rat model of CA-induced BPD. Methods: At embryonic day (E)20, rat litters were treated with intra-amniotic injections of saline, endotoxin (ETX) to model chorioamnionitis, MEx, or ETX plus MEx followed by cesarean section delivery with placental harvest at E22. Placental and lung evaluations were conducted at day 0 and day 14, respectively. To assess the effects of ETX and MEx on lung growth in vitro, E15 lung explants were imaged for distal branching. Results: Placental tissues from ETX-exposed pregnancies showed increased expression of inflammatory markers NLRP-3 and IL-1ß and altered spiral artery morphology. Additionally, infant rats exposed to intrauterine ETX had reduced alveolarization and pulmonary vessel density (PVD), increased right ventricular hypertrophy (RVH), and decreased lung mechanics. Intrauterine MEx therapy of ETX-exposed pups reduced inflammatory cytokines, normalized spiral artery architecture, and preserved distal lung growth and mechanics. In vitro studies showed that MEx treatment enhanced distal lung branching and increased VEGF and SPC gene expression. Conclusions: Antenatal MEx treatment preserved distal lung growth and reduced intrauterine inflammation in a model of CA-induced BPD. We speculate that MEx may provide a novel therapeutic strategy to prevent BPD due to antenatal inflammation.


Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Davide Chiumello ◽  
Matteo Bonifazi ◽  
Tommaso Pozzi ◽  
Paolo Formenti ◽  
Giuseppe Francesco Sferrazza Papa ◽  
...  

Abstract Background We hypothesized that as CARDS may present different pathophysiological features than classic ARDS, the application of high levels of end-expiratory pressure is questionable. Our first aim was to investigate the effects of 5–15 cmH2O of PEEP on partitioned respiratory mechanics, gas exchange and dead space; secondly, we investigated whether respiratory system compliance and severity of hypoxemia could affect the response to PEEP on partitioned respiratory mechanics, gas exchange and dead space, dividing the population according to the median value of respiratory system compliance and oxygenation. Thirdly, we explored the effects of an additional PEEP selected according to the Empirical PEEP-FiO2 table of the EPVent-2 study on partitioned respiratory mechanics and gas exchange in a subgroup of patients. Methods Sixty-one paralyzed mechanically ventilated patients with a confirmed diagnosis of SARS-CoV-2 were enrolled (age 60 [54–67] years, PaO2/FiO2 113 [79–158] mmHg and PEEP 10 [10–10] cmH2O). Keeping constant tidal volume, respiratory rate and oxygen fraction, two PEEP levels (5 and 15 cmH2O) were selected. In a subgroup of patients an additional PEEP level was applied according to an Empirical PEEP-FiO2 table (empirical PEEP). At each PEEP level gas exchange, partitioned lung mechanics and hemodynamic were collected. Results At 15 cmH2O of PEEP the lung elastance, lung stress and mechanical power were higher compared to 5 cmH2O. The PaO2/FiO2, arterial carbon dioxide and ventilatory ratio increased at 15 cmH2O of PEEP. The arterial–venous oxygen difference and central venous saturation were higher at 15 cmH2O of PEEP. Both the mechanics and gas exchange variables significantly increased although with high heterogeneity. By increasing the PEEP from 5 to 15 cmH2O, the changes in partitioned respiratory mechanics and mechanical power were not related to hypoxemia or respiratory compliance. The empirical PEEP was 18 ± 1 cmH2O. The empirical PEEP significantly increased the PaO2/FiO2 but also driving pressure, lung elastance, lung stress and mechanical power compared to 15 cmH2O of PEEP. Conclusions In COVID-19 ARDS during the early phase the effects of raising PEEP are highly variable and cannot easily be predicted by respiratory system characteristics, because of the heterogeneity of the disease.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Anna Lavizzari ◽  
Chiara Veneroni ◽  
Francesco Beretta ◽  
Valeria Ottaviani ◽  
Claudia Fumagalli ◽  
...  

Abstract Background Current criteria for surfactant administration assume that hypoxia is a direct marker of lung-volume de-recruitment. We first introduced an early, non-invasive assessment of lung mechanics by the Forced Oscillation Technique (FOT) and evaluated its role in predicting the need for surfactant therapy. Objectives To evaluate whether lung reactance (Xrs) assessment by FOT within 2 h of birth identifies infants who would need surfactant within 24 h; to eventually determine Xrs performance and a cut-off value for early detection of infants requiring surfactant. Methods We conducted a prospective, observational, non-randomized study in our tertiary NICU in Milan. Eligible infants were born between 27+0 and 34+6 weeks’ gestation, presenting respiratory distress after birth. Exclusion criteria: endotracheal intubation at birth, major malformations participation in other interventional trials, parental consent denied. We assessed Xrs during nasal CPAP at 5 cmH2O at 10 Hz within 2 h of life, recording flow and pressure tracing through a Fabian Ventilator for off-line analysis. Clinicians were blinded to FOT results. Results We enrolled 61 infants, with a median [IQR] gestational age of 31.9 [30.3; 32.9] weeks and birth weight 1490 [1230; 1816] g; 2 infants were excluded from the analysis for set-up malfunctioning. 14/59 infants received surfactant within 24 h. Xrs predicted surfactant need with a cut-off − 33.4 cmH2O*s/L and AUC-ROC = 0.86 (0.76–0.96), with sensitivity 0.85 and specificity 0.83. An Xrs cut-off value of − 23.3 cmH2O*s/L identified infants needing surfactant or respiratory support > 28 days with AUC-ROC = 0.89 (0.81–0.97), sensitivity 0.86 and specificity 0.77. Interestingly, 12 infants with Xrs < − 23.3 cmH2O*s/L (i.e. de-recruited lungs) did not receive surfactant and subsequently required prolonged respiratory support. Conclusion Xrs assessed within 2 h of life predicts surfactant need and respiratory support duration in preterm infants. The possible role of Xrs in improving the individualization of respiratory management in preterm infants deserves further investigation.


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