Pub Date : 2024-10-28DOI: 10.1016/j.resp.2024.104362
Chiara Gattoni, Asghar Abbasi, Carrie Ferguson, Charles W. Lanks, Thomas W. Decato, Harry B. Rossiter, Richard Casaburi, William W. Stringer
Background
Long COVID patients present with a myriad of symptoms that can include fatigue, exercise intolerance and post exertional malaise (PEM). Long COVID has been compared to other post viral syndromes, including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), where a reduction in day 2 cardiopulmonary exercise test (CPET) performance of a two-day CPET protocol is suggested to be a result of PEM. We investigated cardiopulmonary and perceptual responses to a two-day CPET protocol in Long COVID patients.
Methods
15 Long COVID patients [n=7 females; mean (SD) age: 53(11) yr; BMI = 32.2(8.5) kg/m2] performed a pulmonary function test and two ramp-incremental CPETs separated by 24 hr. CPET variables included gas exchange threshold (GET), peak oxygen uptake (O2peak) and peak work rate (WRpeak). Ratings of perceived dyspnoea and leg effort were recorded at peak exercise using the modified 0–10 Borg Scale. PEM (past six months) was assessed using the modified DePaul Symptom Questionnaire (mDSQ). One-sample t-tests were used to test significance of mean difference between days (p<0.05).
Results.
mDSQ revealed PEM in 80 % of patients. Lung function was normal. Responses to day 1 CPET were consistent with the presence of aerobic deconditioning in 40 % of patients (O2peak <80 % predicted, in the absence of evidence of cardiovascular and pulmonary limitations). There were no differences between day-1 and day-2 CPET responses (all p>0.05).
Conclusion
PEM symptoms in Long COVID patients, in the absence of differences in two-day CPET responses separated by 24 hours, suggests that PEM is not due to impaired recovery of exercise capacity between days.
{"title":"Two-day cardiopulmonary exercise testing in long COVID post-exertional malaise diagnosis","authors":"Chiara Gattoni, Asghar Abbasi, Carrie Ferguson, Charles W. Lanks, Thomas W. Decato, Harry B. Rossiter, Richard Casaburi, William W. Stringer","doi":"10.1016/j.resp.2024.104362","DOIUrl":"10.1016/j.resp.2024.104362","url":null,"abstract":"<div><h3>Background</h3><div>Long COVID patients present with a myriad of symptoms that can include fatigue, exercise intolerance and post exertional malaise (PEM). Long COVID has been compared to other post viral syndromes, including myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), where a reduction in day 2 cardiopulmonary exercise test (CPET) performance of a two-day CPET protocol is suggested to be a result of PEM. We investigated cardiopulmonary and perceptual responses to a two-day CPET protocol in Long COVID patients.</div></div><div><h3>Methods</h3><div>15 Long COVID patients [n=7 females; mean (SD) age: 53(11) yr; BMI = 32.2(8.5) kg/m<sup>2</sup>] performed a pulmonary function test and two ramp-incremental CPETs separated by 24 hr. CPET variables included gas exchange threshold (GET), peak oxygen uptake (<span><math><mrow><mover><mrow><mi>V</mi></mrow><mrow><mo>̇</mo></mrow></mover></mrow></math></span>O<sub>2peak</sub>) and peak work rate (W<em>R</em><sub>peak</sub>). Ratings of perceived dyspnoea and leg effort were recorded at peak exercise using the modified 0–10 Borg Scale. PEM (past six months) was assessed using the modified DePaul Symptom Questionnaire (mDSQ). One-sample <em>t</em>-tests were used to test significance of mean difference between days (p<0.05).</div></div><div><h3>Results.</h3><div>mDSQ revealed PEM in 80 % of patients. Lung function was normal. Responses to day 1 CPET were consistent with the presence of aerobic deconditioning in 40 % of patients (<span><math><mrow><mover><mrow><mi>V</mi></mrow><mrow><mo>̇</mo></mrow></mover></mrow></math></span>O<sub>2peak</sub> <80 % predicted, in the absence of evidence of cardiovascular and pulmonary limitations). There were no differences between day-1 and day-2 CPET responses (all p>0.05).</div></div><div><h3>Conclusion</h3><div>PEM symptoms in Long COVID patients, in the absence of differences in two-day CPET responses separated by 24 hours, suggests that PEM is not due to impaired recovery of exercise capacity between days.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104362"},"PeriodicalIF":1.9,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142569342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-19DOI: 10.1016/j.resp.2024.104361
Pedro Alves Machado-Junior , Marcelo Santiago Soares Dias , Ana Beatriz Farias de Souza , Leonardo Spinelli Estevão Lopes , Tatiana Prata Menezes , André Talvani , Laurent Brochard , Frank Silva Bezerra
Background
Mechanical ventilation (MV) is a life support method used to treat patients with respiratory failure. High tidal volumes during MV can cause ventilator-induced lung injury (VILI), but also affect other organs, such as the diaphragm (Dia) causing ventilator-induced diaphragmatic dysfunction (VIDD). VIDD is often associated with a complicated course on MV. Sepsis can induce inflammation and oxidative stress, contributing to the impairment of the Dia and worsening of the prognosis. This study evaluated the additive or synergistic effects of a short course of mechanical ventilation on Dia in healthy and septic adult mice.
Methods
32 adult male C57BL/6 mice were randomly into four groups: Control (CG), non-ventilated animals instilled with saline solution (PBS1x); Lipopolysaccharide (LPS), non-ventilated animals instilled with PBS solution containing lipopolysaccharide; Mechanical Ventilation (MV) for 1 h, ventilated animals instilled with PBS solution; and Mechanical Ventilation and LPS (MV+LPS), ventilated animals instilled with PBS solution containing LPS. At the end of the experimental protocol, the animals were euthanized, then blood and diaphragm tissue samples were collected.
Results
Evaluation of leukocyte/blood parameters and diaphragm muscle showed that MV, LPS and the combination of both were able to increase neutrophil count, creatine kinase, inflammatory mediators and oxidative stress in all groups compared to the control. MV and sepsis combined had additive effects on inflammation and lipid peroxidation.
Conclusions
A short course of Mechanical ventilation promotes inflammation and oxidative stress and, its combination with sepsis further increases local and systemic inflammation.
背景:机械通气(MV)是一种用于治疗呼吸衰竭患者的生命支持方法。机械通气期间的高潮气量可导致呼吸机诱发肺损伤(VILI),但也会影响其他器官,如引起呼吸机诱发膈肌功能障碍(VIDD)的膈肌(Dia)。VIDD 通常与 MV 的复杂病程有关。脓毒症可诱发炎症和氧化应激,导致膈肌受损和预后恶化。本研究评估了短期机械通气对健康和脓毒症成年小鼠 Dia 的叠加或协同作用:方法:将32只成年雄性C57BL/6小鼠随机分为四组:对照组(CG),灌注生理盐水(PBS1x)的非通气动物;脂多糖组(LPS),灌注含有脂多糖的PBS溶液的非通气动物;机械通气1小时组(MV),灌注PBS溶液的通气动物;机械通气和LPS组(MV+LPS),灌注含有LPS的PBS溶液的通气动物。实验结束后,对动物实施安乐术,然后采集血液和膈肌组织样本:结果:对白细胞/血液参数和膈肌的评估表明,与对照组相比,中性粒细胞增多症、脓毒症和两者的结合能增加所有组的中性粒细胞计数、肌酸激酶、炎症介质和氧化应激。中压和脓毒症联合作用对炎症和脂质过氧化具有叠加效应:结论:短期机械通气会促进炎症和氧化应激,与败血症合并使用会进一步增加局部和全身炎症。
{"title":"A short duration of mechanical ventilation alters redox status in the diaphragm and aggravates inflammation in septic mice","authors":"Pedro Alves Machado-Junior , Marcelo Santiago Soares Dias , Ana Beatriz Farias de Souza , Leonardo Spinelli Estevão Lopes , Tatiana Prata Menezes , André Talvani , Laurent Brochard , Frank Silva Bezerra","doi":"10.1016/j.resp.2024.104361","DOIUrl":"10.1016/j.resp.2024.104361","url":null,"abstract":"<div><h3>Background</h3><div>Mechanical ventilation (MV) is a life support method used to treat patients with respiratory failure. High tidal volumes during MV can cause ventilator-induced lung injury (VILI), but also affect other organs, such as the diaphragm (Dia) causing ventilator-induced diaphragmatic dysfunction (VIDD). VIDD is often associated with a complicated course on MV. Sepsis can induce inflammation and oxidative stress, contributing to the impairment of the Dia and worsening of the prognosis. This study evaluated the additive or synergistic effects of a short course of mechanical ventilation on Dia in healthy and septic adult mice.</div></div><div><h3>Methods</h3><div>32 adult male C57BL/6 mice were randomly into four groups: Control (CG), non-ventilated animals instilled with saline solution (PBS1x); Lipopolysaccharide (LPS), non-ventilated animals instilled with PBS solution containing lipopolysaccharide; Mechanical Ventilation (MV) for 1 h, ventilated animals instilled with PBS solution; and Mechanical Ventilation and LPS (MV+LPS), ventilated animals instilled with PBS solution containing LPS. At the end of the experimental protocol, the animals were euthanized, then blood and diaphragm tissue samples were collected.</div></div><div><h3>Results</h3><div>Evaluation of leukocyte/blood parameters and diaphragm muscle showed that MV, LPS and the combination of both were able to increase neutrophil count, creatine kinase, inflammatory mediators and oxidative stress in all groups compared to the control. MV and sepsis combined had additive effects on inflammation and lipid peroxidation.</div></div><div><h3>Conclusions</h3><div>A short course of Mechanical ventilation promotes inflammation and oxidative stress and, its combination with sepsis further increases local and systemic inflammation.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104361"},"PeriodicalIF":1.9,"publicationDate":"2024-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142473463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.resp.2024.104354
Ron Oliven , Arie Oliven , Mostafa Somri , Alan R. Schwartz , Emilia Hardak
Introduction
The genioglossus (GG) is known to be the main tongue protrusor, and therefore plays a major role in breathing. However, due to the fan shape of the GG fibers, it could be assumed that contraction of the anterior fibers of the GG do not cause tongue protrusion. In this study, we examined the effect of contraction of the anterior-vertical fibers of the GG (GGV) on the tongue and their EMG activity during wakefulness and sleep. The findings were compared to those of the longitudinal fibers (GGL), which, based on their orientation, are responsible for tongue protrusion.
Methods
Fine-wire electrode pairs were placed into the GGV and GGL in 11 patients with untreated OSA. Movement of the tongue during electrical stimulation at each site was videoed. The same electrodes were used to record EMG from both sites during respiratory stimulation by inspiratory loading and CO2 rebreathing during wakefulness. During sleep, repetitive flow limitation events were induced with low-level CPAP to augment GG activity.
Results
In all participants, electrical stimulation of GGL and GGV protruded and retracted the tongue, respectively. Respiratory stimulation increased GG activity, but GGV reached only 39 % and 23 % of peak GGL activity during high resistive loading and PCO2 of 65 mmHg, respectively. Flow limitation during sleep increased GGL to levels that were considerably higher than awake baseline, but GGV activity remained tonic or with minimal phasic activity, reaching on average 15 % of GGL peak activity.
Conclusions
Our electrical stimulation findings indicate that GGV is a tongue retractor and depressor. Tongue stimulation for OSA should avoid this area. The EMG results demonstrate that the anterior part of the GG is controlled very differently from the longitudinal protrusive fibers. The GGV responses are similar to those previously found in tongue retractors and peri-pharyngeal muscles other than the GG, in which diminished activation during sleep is likely to be involved in the failure of increasing GGL activity to alleviate flow limitation.
{"title":"Differential neuromotor control of the vertical and longitudinal genioglossus muscle fibers: An overlooked tongue retractor","authors":"Ron Oliven , Arie Oliven , Mostafa Somri , Alan R. Schwartz , Emilia Hardak","doi":"10.1016/j.resp.2024.104354","DOIUrl":"10.1016/j.resp.2024.104354","url":null,"abstract":"<div><h3>Introduction</h3><div>The genioglossus (GG) is known to be the main tongue protrusor, and therefore plays a major role in breathing. However, due to the fan shape of the GG fibers, it could be assumed that contraction of the anterior fibers of the GG do not cause tongue protrusion. In this study, we examined the effect of contraction of the anterior-vertical fibers of the GG (GG<sub>V</sub>) on the tongue and their EMG activity during wakefulness and sleep. The findings were compared to those of the longitudinal fibers (GG<sub>L</sub>), which, based on their orientation, are responsible for tongue protrusion.</div></div><div><h3>Methods</h3><div>Fine-wire electrode pairs were placed into the GG<sub>V</sub> and GG<sub>L</sub> in 11 patients with untreated OSA. Movement of the tongue during electrical stimulation at each site was videoed. The same electrodes were used to record EMG from both sites during respiratory stimulation by inspiratory loading and CO<sub>2</sub> rebreathing during wakefulness. During sleep, repetitive flow limitation events were induced with low-level CPAP to augment GG activity.</div></div><div><h3>Results</h3><div>In all participants, electrical stimulation of GG<sub>L</sub> and GG<sub>V</sub> protruded and retracted the tongue, respectively. Respiratory stimulation increased GG activity, but GG<sub>V</sub> reached only 39 % and 23 % of peak GG<sub>L</sub> activity during high resistive loading and PCO<sub>2</sub> of 65 mmHg, respectively. Flow limitation during sleep increased GG<sub>L</sub> to levels that were considerably higher than awake baseline, but GG<sub>V</sub> activity remained tonic or with minimal phasic activity, reaching on average 15 % of GG<sub>L</sub> peak activity.</div></div><div><h3>Conclusions</h3><div>Our electrical stimulation findings indicate that GG<sub>V</sub> is a tongue retractor and depressor. Tongue stimulation for OSA should avoid this area. The EMG results demonstrate that the anterior part of the GG is controlled very differently from the longitudinal protrusive fibers. The GG<sub>V</sub> responses are similar to those previously found in tongue retractors and peri-pharyngeal muscles other than the GG, in which diminished activation during sleep is likely to be involved in the failure of increasing GG<sub>L</sub> activity to alleviate flow limitation.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104354"},"PeriodicalIF":1.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142401119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.resp.2024.104359
Ricardo Gass , Franciele Plachi , Fernanda O.B. Silva , Talmir Nolasco , Mateus Samuel Tonetto , Leandro S. Goelzer , Paulo T. Muller , Marli M. Knorst , J. Alberto Neder , Danilo C. Berton
Excess exercise ventilation (high ventilation (V̇E)/carbon dioxide output (V̇CO2)) contributes significantly to dyspnea and exercise intolerance since the earlier stages of chronic obstructive pulmonary disease (COPD). A selective pulmonary vasodilator (inhaled nitric oxide) has shown to increase exercise tolerance secondary to lower V̇E/V̇CO2 and dyspnea in this patient population. We aimed to assess whether a clinically more practical option - oral sildenafil - would be associated with similar beneficial effects. In a randomized, placebo-controlled study, twenty-four patients with mild-to-moderate COPD completed, on different days, two incremental cardiopulmonary exercise tests (CPET) one hour after sildenafil or placebo. Eleven healthy participants performed a CPET in a non-interventional visit for comparative purposes with patients when receiving placebo. Patients (FEV1= 69.4 ± 13.5 % predicted) showed higher ventilatory demands (V̇E/V̇CO2), worse pulmonary gas exchange, and higher dyspnea during exercise compared to controls (FEV1= 98.3 ±11.6 % predicted). Contrary to our expectations, however, sildenafil (50 mg; N= 15) did not change exertional V̇E/V̇CO2, dead space/tidal volume ratio, operating lung volumes, dyspnea, or exercise tolerance compared to placebo (P>0.05). Due to the lack of significant beneficial effects, nine additional patients were trialed with a higher dose (100 mg). Similarly, active intervention was not associated with positive physiological or sensory effects. In conclusion, acute oral sildenafil (50 or 100 mg) failed to improve gas exchange efficiency or excess exercise ventilation in patients with predominantly moderate COPD. The current study does not endorse a therapeutic role for sildenafil to mitigate exertional dyspnea in this specific patient subpopulation.
{"title":"Effects of sildenafil on gas exchange, ventilatory, and sensory responses to exercise in subjects with mild-to-moderate COPD: A randomized cross-over trial","authors":"Ricardo Gass , Franciele Plachi , Fernanda O.B. Silva , Talmir Nolasco , Mateus Samuel Tonetto , Leandro S. Goelzer , Paulo T. Muller , Marli M. Knorst , J. Alberto Neder , Danilo C. Berton","doi":"10.1016/j.resp.2024.104359","DOIUrl":"10.1016/j.resp.2024.104359","url":null,"abstract":"<div><div>Excess exercise ventilation (high ventilation (V̇<sub>E</sub>)/carbon dioxide output (V̇CO<sub>2</sub>)) contributes significantly to dyspnea and exercise intolerance since the earlier stages of chronic obstructive pulmonary disease (COPD). A selective pulmonary vasodilator (inhaled nitric oxide) has shown to increase exercise tolerance secondary to lower V̇<sub>E</sub>/V̇CO<sub>2</sub> and dyspnea in this patient population. We aimed to assess whether a clinically more practical option - oral sildenafil - would be associated with similar beneficial effects. In a randomized, placebo-controlled study, twenty-four patients with mild-to-moderate COPD completed, on different days, two incremental cardiopulmonary exercise tests (CPET) one hour after sildenafil or placebo. Eleven healthy participants performed a CPET in a non-interventional visit for comparative purposes with patients when receiving placebo. Patients (FEV<sub>1</sub>= 69.4 ± 13.5 % predicted) showed higher ventilatory demands (V̇<sub>E</sub>/V̇CO<sub>2</sub>), worse pulmonary gas exchange, and higher dyspnea during exercise compared to controls (FEV<sub>1</sub>= 98.3 ±11.6 % predicted). Contrary to our expectations, however, sildenafil (50 mg; N= 15) did not change exertional V̇<sub>E</sub>/V̇CO<sub>2</sub>, dead space/tidal volume ratio, operating lung volumes, dyspnea, or exercise tolerance compared to placebo (<em>P</em>>0.05). Due to the lack of significant beneficial effects, nine additional patients were trialed with a higher dose (100 mg). Similarly, active intervention was not associated with positive physiological or sensory effects. In conclusion, acute oral sildenafil (50 or 100 mg) failed to improve gas exchange efficiency or excess exercise ventilation in patients with predominantly moderate COPD. The current study does not endorse a therapeutic role for sildenafil to mitigate exertional dyspnea in this specific patient subpopulation.</div><div>Clinical trial registry: <span><span>https://ensaiosclinicos.gov.br/rg/RBR-4qhkf4</span><svg><path></path></svg></span></div><div>Web of Science Researcher ID: O-7665–2019</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104359"},"PeriodicalIF":1.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142401120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Post-acute sequelae of SARS-CoV-2 (PASC), or Long COVID, and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are debilitating post-viral conditions with many symptomatic overlaps, including exercise intolerance and autonomic dysfunction. Both conditions are growing in prevalence, and effective safe treatment strategies must be investigated. We hypothesized that inspiratory muscle training (IMT) could be used in PASC and mild to moderate ME/CFS to mitigate symptoms, improve exercise capacity, and improve autonomic function. We recruited healthy controls (n=12; 10 women), people with PASC (n=9; 8 women), and people with mild to moderate ME/CFS (n=12; 10 women) to complete 8 weeks of IMT. This project was registered as a clinical trial (NCT05196529) with clinicaltrials.gov. After completion of IMT, all groups experienced improvements in inspiratory muscle pressure (p<0.001), 6-minute walk distance (p=0.002), resting heart rate (p=0.037), heart rate variability (p<0.05), and symptoms related to sleep (p=0.009). In the ME/CFS group only, after completion of IMT, there were additional improvements with regard to vascular function (p=0.001), secretomotor function (p=0.023), the total weighted score (p=0.005) of the COMPASS 31 autonomic questionnaire, and symptoms related to pain (p=0.016). We found that after 8 weeks of IMT, people with PASC and/or ME/CFS could see some overall improvements in their autonomic function and symptomology.
{"title":"Inspiratory muscle training improves autonomic function in myalgic encephalomyelitis/chronic fatigue syndrome and post-acute sequelae of SARS-CoV-2: A pilot study","authors":"Heather Edgell , Tania J. Pereira , Kathleen Kerr , Riina Bray , Farah Tabassum , Lauren Sergio , Smriti Badhwar","doi":"10.1016/j.resp.2024.104360","DOIUrl":"10.1016/j.resp.2024.104360","url":null,"abstract":"<div><div>Post-acute sequelae of SARS-CoV-2 (PASC), or Long COVID, and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) are debilitating post-viral conditions with many symptomatic overlaps, including exercise intolerance and autonomic dysfunction. Both conditions are growing in prevalence, and effective safe treatment strategies must be investigated. We hypothesized that inspiratory muscle training (IMT) could be used in PASC and mild to moderate ME/CFS to mitigate symptoms, improve exercise capacity, and improve autonomic function. We recruited healthy controls (n=12; 10 women), people with PASC (n=9; 8 women), and people with mild to moderate ME/CFS (n=12; 10 women) to complete 8 weeks of IMT. This project was registered as a clinical trial (NCT05196529) with clinicaltrials.gov. After completion of IMT, all groups experienced improvements in inspiratory muscle pressure (p<0.001), 6-minute walk distance (p=0.002), resting heart rate (p=0.037), heart rate variability (p<0.05), and symptoms related to sleep (p=0.009). In the ME/CFS group only, after completion of IMT, there were additional improvements with regard to vascular function (p=0.001), secretomotor function (p=0.023), the total weighted score (p=0.005) of the COMPASS 31 autonomic questionnaire, and symptoms related to pain (p=0.016). We found that after 8 weeks of IMT, people with PASC and/or ME/CFS could see some overall improvements in their autonomic function and symptomology.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104360"},"PeriodicalIF":1.9,"publicationDate":"2024-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142392855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sevoflurane-induced gasping in mice involves an enormous increase in inspiratory effort, mandibular movement, and a marked decrease in respiratory frequency (fR). We examined differences in breathing patterns and electromyogram activity (EMGSH) of the suprahyoid muscles (SHMs) during eupnea under 3.2 % (1 MAC: minimum alveolar concentration) sevoflurane inhalation and sevoflurane-induced gasping under 6.5 % (2 MAC) sevoflurane inhalation in eight spontaneously breathing, tracheally intubated, adult mice. We found that the phasic EMGSH is obtained only during inspiration in eupnea and gasping and that integrated EMGSH increases more, as a percent of baseline (% baseline) than tidal volume (VT) during gasping (median [interquartile range]; integrated EMGSH: 720 [425–1965] vs. VT: 300 [238–373], P < 0.05). We also found that the onset of EMGSH precedes the start of airflow while maintaining a bell-shaped EMGSH contour, which characterizes the EMG of upper airway dilator (UAD) muscles during eupnea and gasping. Vigorous respiratory-related mandibular movements were never observed during eupnea but were observed in seven of 8 mice during sevoflurane-induced gasping. Our observations indicate that SHMs act as a preferentially activating UAD muscle, contributing to the development of mandibular respiratory movements.
{"title":"The activity of suprahyoid muscles during sevoflurane-induced gasping in mice","authors":"Saki Taiji, Takashi Nishino, Hisayo Jin, Mayumi Hashida, Shiroh Isono","doi":"10.1016/j.resp.2024.104355","DOIUrl":"10.1016/j.resp.2024.104355","url":null,"abstract":"<div><div>Sevoflurane-induced gasping in mice involves an enormous increase in inspiratory effort, mandibular movement, and a marked decrease in respiratory frequency (fR). We examined differences in breathing patterns and electromyogram activity (EMG<sub>SH</sub>) of the suprahyoid muscles (SHMs) during eupnea under 3.2 % (1 MAC: minimum alveolar concentration) sevoflurane inhalation and sevoflurane-induced gasping under 6.5 % (2 MAC) sevoflurane inhalation in eight spontaneously breathing, tracheally intubated, adult mice. We found that the phasic EMG<sub>SH</sub> is obtained only during inspiration in eupnea and gasping and that integrated EMG<sub>SH</sub> increases more, as a percent of baseline (% baseline) than tidal volume (V<sub>T</sub>) during gasping (median [interquartile range]; integrated EMG<sub>SH</sub>: 720 [425–1965] vs. V<sub>T</sub>: 300 [238–373], P < 0.05). We also found that the onset of EMG<sub>SH</sub> precedes the start of airflow while maintaining a bell-shaped EMG<sub>SH</sub> contour, which characterizes the EMG of upper airway dilator (UAD) muscles during eupnea and gasping. Vigorous respiratory-related mandibular movements were never observed during eupnea but were observed in seven of 8 mice during sevoflurane-induced gasping. Our observations indicate that SHMs act as a preferentially activating UAD muscle, contributing to the development of mandibular respiratory movements.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104355"},"PeriodicalIF":1.9,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142381515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.resp.2024.104357
Mehdi Eslami-Behroozi, Payam Shahsavar, Reyhaneh Vali, Mohammad Reza Raoufy
Respiratory patterns were investigated in male Sprague-Dawley rats throughout their lifespan, from weanling (1 month) to old age (24 months), under natural conditions. Both inter-breath interval (IBI) and respiratory volume (RV) were examined. Sample entropy suggested increasing irregularity in IBI but decreasing irregularity in RV until 12 months. According to detrended fluctuation analysis, alpha exponent of the IBI showed a bimodal pattern around the value 0.7. From 1–15 months, the alpha exponent for RV generally decreased to the value 0.5, but it increased again as the animals neared the end of their lifespan. Cross-sample entropy revealed increasing synchronization between IBI and RV until 12 months, then plateauing. Many measures demonstrated a transition around 12 months, potentially reflecting maturation of respiratory control mechanisms. The findings characterize complex dynamics of respiratory patterns across the rat lifespan, providing a normative foundation to identify deviations indicative of dysfunction or disease.
{"title":"Breathing pattern alteration from weanling to old age in male Sprague-Dawley rats","authors":"Mehdi Eslami-Behroozi, Payam Shahsavar, Reyhaneh Vali, Mohammad Reza Raoufy","doi":"10.1016/j.resp.2024.104357","DOIUrl":"10.1016/j.resp.2024.104357","url":null,"abstract":"<div><div>Respiratory patterns were investigated in male Sprague-Dawley rats throughout their lifespan, from weanling (1 month) to old age (24 months), under natural conditions. Both inter-breath interval (IBI) and respiratory volume (RV) were examined. Sample entropy suggested increasing irregularity in IBI but decreasing irregularity in RV until 12 months. According to detrended fluctuation analysis, alpha exponent of the IBI showed a bimodal pattern around the value 0.7. From 1–15 months, the alpha exponent for RV generally decreased to the value 0.5, but it increased again as the animals neared the end of their lifespan. Cross-sample entropy revealed increasing synchronization between IBI and RV until 12 months, then plateauing. Many measures demonstrated a transition around 12 months, potentially reflecting maturation of respiratory control mechanisms. The findings characterize complex dynamics of respiratory patterns across the rat lifespan, providing a normative foundation to identify deviations indicative of dysfunction or disease.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104357"},"PeriodicalIF":1.9,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142372715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-29DOI: 10.1016/j.resp.2024.104358
Cory M. Smith, Owen F. Salmon
Purpose
Examine the cardiovascular, muscular function, cognitive, and neural plastic responses to determine the safety and effectiveness of acute Intermittent hypoxia (AIH) at a low, high, and control fractional inspired oxygen (FiO2) dosage
Methods
Thirteen human participants performed 30-min of AIH in 60-s intervals at FiO2’s of 0.21 (AIH21), 0.15 (AIH15), and 0.09 (AIH9). Heart rate variability (root mean squared of successive differences; RMSSD), heart rate, oxygen saturation (SpO2), blood pressure, muscular strength, neuromuscular activation, cerebral hemodynamic responses, cognition, symptomology, and brain-derived neurotrophic factor (BDNF) responses were measured before (Pre-AIH), after (post-AIH), and at 20-min of recovery (Recovery-AIH)
Results
There were no differences between AIH protocols for heart rate, RMSSD, blood pressure, or SpO2. Muscular strength improved Post-AIH for AIH15 (10 %) and AIH9 (14 %) and remained elevated (6 %) at Recovery-AIH. Neuromuscular activation increased Pre-AIH to Post-AIH for AIH15 (10 %) and AIH9 (11 %). Cerebral hemodynamic responses were not impacted between conditions. Both AIH15 and AIH9 increased BDNF Post-AIH (62 %) and Recovery-AIH (63 %)
Conclusion
Acute intermittent hypoxia is generally safe and effective at producing neural plastic responses, but further examination of co-occurring cardiovascular diseases is needed. This study provides safety focused findings which will widen the adoption and refinement of AIH protocols
{"title":"Safety and effectiveness of acute intermittent hypoxia during a single treatment at different hypoxic severities","authors":"Cory M. Smith, Owen F. Salmon","doi":"10.1016/j.resp.2024.104358","DOIUrl":"10.1016/j.resp.2024.104358","url":null,"abstract":"<div><h3>Purpose</h3><div>Examine the cardiovascular, muscular function, cognitive, and neural plastic responses to determine the safety and effectiveness of acute Intermittent hypoxia (AIH) at a low, high, and control fractional inspired oxygen (FiO<sub>2</sub>) dosage</div></div><div><h3>Methods</h3><div>Thirteen human participants performed 30-min of AIH in 60-s intervals at FiO2’s of 0.21 (AIH<sub>21</sub>), 0.15 (AIH<sub>15</sub>), and 0.09 (AIH<sub>9</sub>). Heart rate variability (root mean squared of successive differences; RMSSD), heart rate, oxygen saturation (SpO2), blood pressure, muscular strength, neuromuscular activation, cerebral hemodynamic responses, cognition, symptomology, and brain-derived neurotrophic factor (BDNF) responses were measured before (Pre-AIH), after (post-AIH), and at 20-min of recovery (Recovery-AIH)</div></div><div><h3>Results</h3><div>There were no differences between AIH protocols for heart rate, RMSSD, blood pressure, or SpO2. Muscular strength improved Post-AIH for AIH<sub>15</sub> (10 %) and AIH<sub>9</sub> (14 %) and remained elevated (6 %) at Recovery-AIH. Neuromuscular activation increased Pre-AIH to Post-AIH for AIH15 (10 %) and AIH<sub>9</sub> (11 %). Cerebral hemodynamic responses were not impacted between conditions. Both AIH<sub>15</sub> and AIH9 increased BDNF Post-AIH (62 %) and Recovery-AIH (63 %)</div></div><div><h3>Conclusion</h3><div>Acute intermittent hypoxia is generally safe and effective at producing neural plastic responses, but further examination of co-occurring cardiovascular diseases is needed. This study provides safety focused findings which will widen the adoption and refinement of AIH protocols</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104358"},"PeriodicalIF":1.9,"publicationDate":"2024-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142352852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-24DOI: 10.1016/j.resp.2024.104356
Avery E. Dakin , Michelle S. Troche
Purpose
Expiratory muscle strength training (EMST) is a resistance exercise used to improve maximal expiratory pressure and airway protective functions (cough and swallow) in clinical populations. Although ratings of perceived exertion/effort (RPE) are commonly used in exercise prescription and monitoring, they have been underutilized in EMST and require investigation. Our study aims were to: (1) examine how healthy adults rate their effort using the EMST-150 device and MicroRPM respiratory manometer; (2) assess variability in RPE; and (3) compare RPE and relative expiratory pressures obtained from the two devices.
Method
Healthy adults completed thirty randomized expiratory maneuvers into a respiratory manometer and an EMST-150 device. RPE was measured using the Borg Category Ratio Scale. Linear mixed multilevel models were used for Aim 1 and 3, and coefficient of variation was used for Aim 2.
Results
Twenty healthy adults (Median age: 24.5 years) participated. Results demonstrated a strong positive relationship between resistive load and perceived effort when using both devices. Intra-individual variability in perceived effort decreased as resistive load increased. Participants produced an average of 18.2 % lower expiratory pressure when blowing into the manometer (relative to their maximum) than when blowing into the EMST device.
Discussion
Our results support the utilization of RPE in EMST research and clinical practice. The addition of RPE as a measure of intensity during respiratory exercise prescription may be used in future research to help refine EMST protocols and improve rehabilitation outcomes.
{"title":"Ratings of perceived effort during expiratory pressure tasks in healthy adults","authors":"Avery E. Dakin , Michelle S. Troche","doi":"10.1016/j.resp.2024.104356","DOIUrl":"10.1016/j.resp.2024.104356","url":null,"abstract":"<div><h3>Purpose</h3><div>Expiratory muscle strength training (EMST) is a resistance exercise used to improve maximal expiratory pressure and airway protective functions (cough and swallow) in clinical populations. Although ratings of perceived exertion/effort (RPE) are commonly used in exercise prescription and monitoring, they have been underutilized in EMST and require investigation. Our study aims were to: (1) examine how healthy adults rate their effort using the EMST-150 device and MicroRPM respiratory manometer; (2) assess variability in RPE; and (3) compare RPE and relative expiratory pressures obtained from the two devices.</div></div><div><h3>Method</h3><div>Healthy adults completed thirty randomized expiratory maneuvers into a respiratory manometer and an EMST-150 device. RPE was measured using the Borg Category Ratio Scale. Linear mixed multilevel models were used for Aim 1 and 3, and coefficient of variation was used for Aim 2.</div></div><div><h3>Results</h3><div>Twenty healthy adults (Median age: 24.5 years) participated. Results demonstrated a strong positive relationship between resistive load and perceived effort when using both devices. Intra-individual variability in perceived effort decreased as resistive load increased. Participants produced an average of 18.2 % lower expiratory pressure when blowing into the manometer (relative to their maximum) than when blowing into the EMST device.</div></div><div><h3>Discussion</h3><div>Our results support the utilization of RPE in EMST research and clinical practice. The addition of RPE as a measure of intensity during respiratory exercise prescription may be used in future research to help refine EMST protocols and improve rehabilitation outcomes.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104356"},"PeriodicalIF":1.9,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142352853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-19DOI: 10.1016/j.resp.2024.104351
Stephen M. Johnson, Sarah M. Johnson, Jyoti J. Watters, Tracy L. Baker
Substance P (SubP) and endomorphin-2 (Endo2) are co-localized presynaptically in vesicles of neurons adjacent to inspiratory rhythm-generating pre-Botzinger Complex (preBotC) neurons but the effects of co-released SubP and Endo2 on respiratory motor control are not known. To address this question, SubP alone or a combination of SubP and Endo2 (SubP/Endo2) were bath-applied in a sustained (15-min) or intermittent (5-min application, 5-min washout, x3) pattern at 10–100 nM to neonatal rat brainstem-spinal cord preparations. During neuropeptide application, SubP/Endo2 co-applications generally attenuated SubP-induced increases in burst frequency and decreases in burst amplitude. With respect to frequency plasticity (long-lasting increase in burst frequency 60 min post-neuropeptide application), SubP-induced frequency plasticity was increased with sustained SubP/Endo2 co-applications at 20 and 100 nM. Intermittent SubP/Endo2 co-applications tended to decrease the level of frequency plasticity induced by intermittent SubP alone applications. SubP/Endo2 co-applications revealed potentially new functions for neurokinin-1 (NK1R) and mu-opioid (MOR) receptors on respiratory rhythm-generating medullary neurons.
{"title":"Endomorphin-2 (Endo2) and substance P (SubP) co-application attenuates SubP-induced excitation and alters frequency plasticity in neonatal rat in vitro preparations","authors":"Stephen M. Johnson, Sarah M. Johnson, Jyoti J. Watters, Tracy L. Baker","doi":"10.1016/j.resp.2024.104351","DOIUrl":"10.1016/j.resp.2024.104351","url":null,"abstract":"<div><div>Substance P (SubP) and endomorphin-2 (Endo2) are co-localized presynaptically in vesicles of neurons adjacent to inspiratory rhythm-generating pre-Botzinger Complex (preBotC) neurons but the effects of co-released SubP and Endo2 on respiratory motor control are not known. To address this question, SubP alone or a combination of SubP and Endo2 (SubP/Endo2) were bath-applied in a sustained (15-min) or intermittent (5-min application, 5-min washout, x3) pattern at 10–100 nM to neonatal rat brainstem-spinal cord preparations. During neuropeptide application, SubP/Endo2 co-applications generally attenuated SubP-induced increases in burst frequency and decreases in burst amplitude. With respect to frequency plasticity (long-lasting increase in burst frequency 60 min post-neuropeptide application), SubP-induced frequency plasticity was increased with sustained SubP/Endo2 co-applications at 20 and 100 nM. Intermittent SubP/Endo2 co-applications tended to decrease the level of frequency plasticity induced by intermittent SubP alone applications. SubP/Endo2 co-applications revealed potentially new functions for neurokinin-1 (NK1R) and mu-opioid (MOR) receptors on respiratory rhythm-generating medullary neurons.</div></div>","PeriodicalId":20961,"journal":{"name":"Respiratory Physiology & Neurobiology","volume":"331 ","pages":"Article 104351"},"PeriodicalIF":1.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142294047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}