Respiratory physiology & neurobiology
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Respir Physiol Neurobiol · Aug 2017
Validity of thoracic respiratory inductive plethysmography in high body mass index subjects.
We aim to evaluate thoracic respiratory inductive plethysmography (RIP) in high body mass index (BMI) subjects with a pneumotachometer (PT) as a reference. We simultaneously evaluated spontaneous breathing by RIP and PT in 10 low and 10 high BMI subjects at rest and in moderate exercise. ⋯ ANOVA revealed the effects of perimeter and simulated adiposity (p<0.001 for both). We concluded that thoracic perimeter and deformity of adipose tissue are responsible for biases in RIP response in high BMI subjects.
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Respir Physiol Neurobiol · Feb 2020
Cystic fibrosis transmembrane conductance regulator ameliorates lipopolysaccharide-induced acute lung injury by inhibiting autophagy through PI3K/AKT/mTOR pathway in mice.
The beneficial role of Cystic fibrosis transmembrane conductance regulator (CFTR) was reported in acute lung injury (ALI), however, there was no direct evidence supporting the relationship between CFTR and cell autophagy in ALI. Here, this study is to analyze the protective role of CFTR on autophagy in lipopolysaccharide (LPS)-induced ALI mice and its special mechanism. ⋯ CFTR could inhibit cell autophagy by enhancing PI3K/AKT/mTOR signaling pathway, thereby playing a protective role in LPS-induced ALI in mice.
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Respir Physiol Neurobiol · Dec 2016
Intratidal recruitment/derecruitment persists at low and moderate positive end-expiratory pressure in paediatric patients.
In paediatric patients positive end-expiratory pressure (PEEP) is traditionally set lower than in adults. We investigated whether moderately higher PEEP improves respiratory mechanics and regional ventilation. Therefore, 40 children were mechanically ventilated with PEEP 2 and 5cmH2O. ⋯ A higher PEEP improved peripheral ventilation. In conclusion, mechanically ventilated paediatric patients undergo intratidal recruitment/derecruitment which occurs more prominently in younger than in older children. A PEEP of 5cmH2O does not fully prevent intratidal recruitment/derecruitment but homogenizes regional ventilation in comparison to 2cmH2O.
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Respir Physiol Neurobiol · Jun 2018
Randomized Controlled TrialAcute bronchodilator therapy does not reduce wasted ventilation during exercise in COPD.
This randomized, double-blind, crossover study aimed to determine if acute treatment with inhaled bronchodilators, by improving regional lung hyperinflation and ventilation distribution, would reduce dead space-to-tidal volume ratio (VD/VT); thus contributing to improved exertional dyspnea in COPD. Twenty COPD patients (FEV1 = 50 ± 15% predicted; mean ± SD) performed pulmonary function tests and symptom-limited constant-work rate exercise at 75% peak-work rate (with arterialized capillary blood gases) after nebulized bronchodilator (BD; ipratropium 0.5mg + salbutamol 2.5 mg) or placebo (PL; normal saline). After BD versus PL: Functional residual capacity decreased by 0.4L (p = .0001). ⋯ There was no significant difference in arterial CO2 tension or VD/VT, but alveolar ventilation increased by 3.8 ± 5.5 L/min (p = .02). Post-BD improvements in respiratory mechanics explained 51% of dyspnea reduction at a standardized exercise time. Bronchodilator-induced improvements in respiratory mechanics were not associated with reduced wasted ventilation - a residual contributory factor to exertional dyspnea during exercise in COPD.
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Respir Physiol Neurobiol · Apr 2020
Kölliker-Fuse/Parabrachial complex mu opioid receptors contribute to fentanyl-induced apnea and respiratory rate depression.
Overdoses caused by the opioid agonist fentanyl have increased exponentially in recent years. Identifying mechanisms to counter progression to fatal respiratory apnea during opioid overdose is desirable, but difficult to study in vivo. The pontine Kölliker-Fuse/Parabrachial complex (KF/PB) provides respiratory drive and contains opioid-sensitive neurons. ⋯ Higher concentrations caused prolonged apnea, interrupted by occasional apneustic-like bursts. Application of CTAP, a selective mu opioid receptor antagonist, directly into the KF/PB complex reversed and prevented fentanyl-induced apnea by increasing the frequency of apneustic-like bursting. These results demonstrate that countering opioid effects in the KF/PB complex is sufficient to restore phasic respiratory output at a rate similar to pre-fentanyl conditions, which could be beneficial in opioid overdose.