Forced Inspiratory Flow Volume Curve in Patients with Obstructive Sleep Apnea-Hypopnea Syndrome

Objective: Obstructive sleep apnea-hypopnea syndrome (OSA) is a disease of obstructive apnea or hypopnea caused by a repeated partial or complete collapse of the upper airway during sleep. The inspiratory part of the flow-volume curve (F-V curve) can be used as an auxiliary means to evaluate upper airway obstruction in adults. This study is to evaluate the ability of the F-V curve to predict the OSA and explore inspiratory indicators related to airway obstruction during sleep. Methods: There were 332 patients included in this cross-sectional study, who were accompanied by snoring, daytime sleepiness and other symptoms, with suspicion of OSA. According to the nocturnal polysomnography, the subjects were distributed into mild to moderate OSA group, severe OSA group and non-OSA group. A pulmonary function test was used to collect the subjects’ spirometry and F-V curves. Results: There was no significant difference in a variety of indices derived from the F-V curve between OSA and normal subjects, including 25% inspiratory flow rate, middle inspiratory flow rate, 75% inspiratory flow rate, peak flow rate, and forced inspiratory flow rate in the first second. The pulmonary function parameters were significantly correlated with the weight, age and sex of the subjects. Conclusion: These findings suggest that the inspiratory curve of pulmonary function cannot evaluate the upper airway abnormalities in patients with obstructive apnea-hypopnea syndrome.

Effect of preoperative inspiratory muscle training on postoperative outcomes in patients undergoing cardiac surgery:A systematic review and meta-analysis

BACKGROUND Cardiovascular disease is the most prevalent disease worldwide and places a great burden on the health and economic welfare of patients.Cardiac surgery is an important way to treat cardiovascular disease,but it can prolong mechanical ventilation time,intensive care unit(ICU)stay,and postoperative hospitalization for patients.Previous studies have demonstrated that preoperative inspiratory muscle training could decrease the incidence of postoperative pulmonary complications.AIM To explore the effect of preoperative inspiratory muscle training on mechanical ventilation time,length of ICU stay,and duration of postoperative hospitalization after cardiac surgery.METHODS A literature search of PubMed,Web of Science,Cochrane Library,EMBASE,China National Knowledge Infrastructure,WanFang,and the China Science and Technology journal VIP database was performed on April 13,2022.The data was independently extracted by two authors.The inclusion criteria were:(1)Randomized controlled trial;(2)Accessible as a full paper;(3)Patients who received cardiac surgery;(4)Preoperative inspiratory muscle training was implemented in these patients;(5)The study reported at least one of the following:Mechanical ventilation time,length of ICU stay,and/or duration of postoperative hospitalization;and(6)In English language.RESULTS We analyzed six randomized controlled trials with a total of 925 participants.The pooled mean difference of mechanical ventilation time was-0.45 h[95%confidence interval(CI):-1.59-0.69],which was not statistically significant between the intervention group and the control group.The pooled mean difference of length of ICU stay was 0.44 h(95%CI:-0.58-1.45).The pooled mean difference of postoperative hospitalization was-1.77 d in the intervention group vs the control group[95%CI:-2.41-(-1.12)].CONCLUSION Preoperative inspiratory muscle training may decrease the duration of postoperative hospitalization for patients undergoing cardiac surgery.More high-quality studies are needed to confirm our conclusion.

Nikethamide affects inspiratory neuron discharge in the nucleus retrofacialis medial region in brain slices from neonatal rats

BACKGROUND： Nikethamide, a respiratory center stimulant, is widely used in China. However, its effects on the central nervous system and medullary respiratory center remain poorly understood. OBJECTIVE： To investigate the influence of nikethamide on inspiratory neuron discharge in the medial region of the nucleus retrofacialis in neonatal rats, based on the observations addressing rhythmic respiratory discharge generated by the basic medullary respiratory center and various respiration neuron discharges in brain slices. DESIGN, TIME AND SETTING： A controlled, observational study utilizing in vitro neuroelectrophysiology was performed at the Department of Physiology in Southern Medical University between September and December in 2007. MATERIALS： Nikethamide was purchased from Sigma, USA; BL-420E biological signal collection and manaclement system was provided by Chengdu TME Technology, China.METHODS： Isolated medulla-spinal cord preparations were collected from neonatal Sprague Dawley rats, aged 1-3 days. Tissues were divided to include the medial region of the nucleus retrofacialis, ventral respiratory, and dorsal respiratory groups. Subsequently, modified Kreb＇s solution and 5 μg/mL nikethamide-containing modified Kreb＇s solution were consecutively perfused into the medial region of the nucleus retrofacialis in neonatal rat brain slices. MAIN OUTCOME MEASURES： Hypoglossal nerve root respiratory-related rhythmic discharge activities and inspiratory neuron discharges were recorded with an adsorption electrode and microelectrode. RESULTS Nikethamide resulted in prolonged inspiratory neuron discharge time, shortened respiratory cycle and expiratory time. Nikethamide intervention resulted in enhanced integral amplitude of some inspiratory neurons with no changes in discharge frequency or increased discharge frequency in remaining inspiratory neurons with no changes in integral amplitude. CONCLUSION： Nikethamide excites inspiratory neurons in the basic rhythmic respiration and medullary respiratory center, in addition to increased inspiratory neuron and neural network excitability.

Determinants of inspiratory muscle function in healthy children

Background: Children are affected by disorders that have an impact on the respiratory muscles. Inspiratory muscle function can be assessed by means of the noninvasive tension–time index of the inspiratory muscles(TTImus). Our objectives were to identify the determinants of TTImus in healthy children and to report normal values of TTImus in this population.Methods: We measured weight, height, upper arm muscle area(UAMA), and TTImusin 96 children aged 6–18 years. The level and frequency of aerobic activity was assessed by questionnaire.Results: TTImuswas significantly lower in male subjects(0.095 ± 0.038, mean ± SD) compared with female subjects(0.126 ± 0.056)(p = 0.002).TTImus was significantly lower in regularly exercising(0.093 ± 0.040) compared with nonexercising subjects(0.130 ± 0.053)(p < 0.001). TTImus was significantly negatively related to age(r =-0.239, p = 0.019), weight(r =-0.214, p = 0.037), height(r =-0.355, p < 0.001), and UAMA(r =-0.222, p = 0.030). Multivariate logistic regression analysis revealed that height and aerobic exercise were significantly related to TTImus independently of age, weight, and UAMA. The predictive regression equation for TTImus in male subjects was TTImus = 0.228-0.001 × height(cm), and in female subjects it was TTImus = 0.320-0.001 × height(cm).Conclusion: Gender, age, anthropometry, skeletal muscularity, and aerobic exercise are significantly associated with indices of inspiratory muscle function in children. Normal values of TTImus in healthy children are reported.

Predicting maximum voluntary ventilation in normal healthy individuals using indirect inspiratory muscle strength measurements: a correlation study

Maximum Voluntary Ventilation (MVV), one of the components of Pulmonary Function Testing (PFT), has multiple uses. Various factors including the inspiratory muscle strength (IMS) influence its magnitude. Our aim was to quantify the IMS indirectly using an economical and non invasive bedside assessment tool, determine its association with MVV and then develop a predictive equation for MVV. 41 healthy non-athletic physical therapy students participated in the study. IMS measurement was performed with a sphygmomanometer. Average of the three net deflections in sphygmomanometer following deepest possible breaths was taken as indirect measurement of IMS in mm of Hg. MVV was measured according to ATS guidelines using a spirometer. Results from the data analysis revealed a significant correlation between IMS and MVV(r = 0.83, p < 0.001) and the coefficient of determination = 0.68. So, we developed a regression equation: Y = 1.9669(X) + 49.838 with SEE: 13.02L/min and ANOVA for the equation was (F=68.9, p < 0.001). Hence, it can be concluded that a strong correlation between the indirect IMS and MVV was established and a predictive equation to estimate MVV was developed. This equation proved to have a high predictive value with a small error of estimation. This indicates that the value of the indirect IMS measurement obtained using the sphygmomanometer can be used to estimate MVV in normal healthy individuals without the use of a conventional spirometer.

Prolonged Intermittent Running Induces Inspiratory-Muscle Fatigue in Female Runners

Inspiratory-muscle fatigue （IMF） may occur after long-duration or continuous short-duration exercise and may limit exercise performance. Daily athletics training is often intermittent, but it is unclear if intermittent running induces IMF. We investigated IMF after a maximal anaerobic running test （MART） and maximal intermittent graded exercise test. Nine female middle-distance （400 or 800 m） runners performed MART and maximal intermittent graded exercise tests. Maximal inspiratory pressure （MIP） was measured before and after each test using a portable autospirometer. There was no significant difference in mean MIPs before （105 ± 24 cm H2O） and after （104 ± 28 cm H2O） the MART （P = 0.95, effect size [ES] as partial η2 = 0.01）. Mean M IP after the maximal intermittent graded exercise test （97 ± 26 cm H2O） was lower than before exercise （105 ± 27 cm H2O） （P = 0.01, 1]2 = 0.83） Mean IMF was higher for the maximal intermittent graded exercise test （8.5 ± 4.2 cm H2O） than for the MART （0.8 ± 4.1 cm H2O） （P = 0.01, ES as Cohen＇s d = 1.88）. IMF occurs after relatively long-duration intermittent running exercise. Coaches may consider recommending inspiratory-muscle training or warm-up to reduce IMF resulting from relatively long-duration intermittent running exercise.

Reduction in pulmonary complications in high risk patients undergoing surgery for total hip replacement under general anesthesia by preoperative intensive inspiratory muscle training:A randomized controlled clinical trial

Objective： To evaluate the effects of preoperative inspiratory muscle training （IMT） on the incidence of atelectasis in patients at high risk of postoperative pulmonary complications scheduled for elective total hip replacement surgery under general anesthesia. Methods： Thirty two high-risk patients undergoing elective total hip replacement surgery under general anesthesia were chosen from Nanjing Medical University, Affiliated Nanjing First Hospital. In this single-blind randomized controlled clinical triM, patients were randomly assigned to receive preoperative inspiratory muscle training or conventional treatment （CT）. The major effectiveness outcome variables were atelectasis and duration of postoperative hospitalization. Results： Both groups were comparable prior to surgery. Seven patients in the CT group and 3 in the IMT group developed atelectasis （P = 0.25）. Median duration of postoperative hospitalization was 13 days （range, 10～17 days） in the IMT group versus 16 days （range, 11～23 days） in the CT group （Mann- Whitney U statistics, Z = -2.22, P = 0.03）. Mean postoperative inspiratory pressure was 5% higher in the IMT group. Conclusion： Preoperative intensive inspiratory muscle training appears to reduce the incidence of atelectasis and duration of postoperative hospitalization in patients at high risk of developing postoperative pulmonary complications who were scheduled for elective total hip replacement surgery under general anesthesia.

The impact of inspiratory muscle training on exercise capacity and inspiratory muscle strength in heart failure patients:a meta-analysis

Objective:To systematically evaluate the therapeutic effects of inspiratory muscle training(IMT)on cardiopulmonary functions in patients with heart failure.Methods:PubMed,EMbase,the Cochrane Library,Web of Science,CBM,WanFang Data,VIP,and CNKI databases were searched to collect randomized controlled trials about the effects of IMT on cardiopulmonary function in patients with heart failure.Meta-analysis was performed using RevMan 5.3 software after two researchers independently screened the literatures,extracted the data,and evaluated the risk of bias.Results:A total of 20 articles with 1,415 patients were included.Meta-analysis showed that IMT was able to increase the 6-minute walking distance(mean difference(MD)=59.41,95%confidence interval(CI)(51.02–67.80),P<0.001)and maximum inspiratory pressure(MD=15.59,95%CI(12.96–18.21),P<0.001)in patients with heart failure compared with the control group.But there was no statistical difference in peak oxygen uptake(MD=1.37,95%CI(?0.57–3.30),P=0.17),first second forced expiratory volume(MD=?5.79,95%CI(?12.23–0.65),P=0.08)and forced vital capacity(MD=?0.45,95%CI(?6.39–5.49),P=0.88)between the control and the experimental group.Conclusion:Available evidence suggested that IMT seemed to be a useful strategy for improving exercise capacity and inspiratory muscle strength in heart failure patients.Limited by the quantity and quality of the included studies,the above conclusions need to be verified by more high-quality studies.

Effects of dynamic ventilatory factors on ventilatorinduced lung injury in acute respiratory distress syndrome dogs

BACKGROUND： Mechanical ventilation is a double-edged sword to acute respiratory distress syndrome （ARDS） including lung injury, and systemic inflammatory response high tidal volumes are thought to increase mortality. The objective of this study is to evaluate the effects of dynamic ventilatory factors on ventilator induced lung injury in a dog model of ARDS induced by hydrochloric acid instillation under volume controlled ventilation and to investigate the relationship between the dynamic factors and ventilator-induced lung injuries （VILI） and to explore its potential mechanisms.METHODS： Thirty-six healthy dogs were randomly divided into a control group and an experimental group. Subjects in the experimental group were then further divided into four groups by different inspiratory stages of flow. Two mL of alveolar fluid was aspirated for detection of IL-8 and TNF-α. Lung tissue specimens were also extracted for total RNA, IL-8 by western blot and observed under an electronic microscope.RESULTS： IL-8 protein expression was significantly higher in group B than in groups A and D. Although the IL-8 protein expression was decreased in group C compared with group B, the difference was not statistically significant. The TNF-a ray degree of group B was significantly higher than that in the other groups （P〈0.01）, especially in group C （P〉0.05）. The alveolar volume of subjects in group B was significantly smaller, and cavity infiltration and cell autolysis were marked with a significant thicker alveolar septa, disorder of interval structures, and blurring of collagenous and elastic fiber structures. A large number of necrotic debris tissue was observed in group B.CONCLUSION： Mechanical ventilation with a large tidal volume, a high inspiratory flow and a high ventilation frequency can cause significant damage to lung tissue structure. It can significantly increase the expression of TNF-α and IL-8 as well as their mRNA expression. Furthermore, the results of our study showed that small tidal ventilation significantly reduces the release of proinflammatory media. This finding suggests that greater deterioration in lung injury during ARDS is associated with high inspiratory flow and high ventilation rate.

Respiratory physiotherapy in gastroesophageal reflux disease:A review article

Gastroesophageal reflux disease(GERD) is a frequen disorder which is expensive to diagnose and treat Initiating therapy with empiric trial of proton-pump inhibitor is a well established strategy; however symptoms of GERD do often persist regardless of effective medication. Nowadays, increasing interest concerning the efficacy and safety of chronic acid suppression with proton-pump inhibitors(PPIs), prompts a consideration fo GERD treatment strategies related to the basic physiology of the lower esophageal sphincter, including modulationof its tone and ending of spontaneous transient lower esophageal sphincter relaxation, which contributes to reflux. Together, the lower esophageal sphincter and the crural diaphragm represent the major antireflux barrier, protecting the esophagus from reflux of gastric content. In order to prevent the need for enduring PPIs therapy or surgical procedures, substitute therapeutics approaches are being researched. Recently, studies have focused on the response of the respiratory muscles to inspiratory muscle training. As a result, inspiratory muscle training has emerged as a potential alternative for treatment of gastroesophageal reflux. The present report reviews the physiologic factors contributing to GERD, and presents the newly developed therapies that can be applied either alone or in association with available efficient GERD therapy.

Measurement of individual hypoxic sensitivity by means of mouth occlusion pressure

mouth occlusion pressure (P0.1) rather than inspiratory ventilation （V1）and mean inspiratory airflow （（?）） was used for expounding the mechanism of indi-vidual hypoxic sensitivity.Eighteen young healthy male subjects participated inthe experiment of progressive isocapnic hypoxia produced by rebreathing method.The results showed that there were significantly linear relationship （P【0.01） be-tween V1 and P0.1,as well as （?） and P0.1 during the hypoxic loading of twoend-tidal carbon dioxide pressure (PETCO2 levels,4.3 and 5.9kPa.Ventilation in-creased with progressive hypoxia.Therefore,they all represent the useful indexesof inspiratory drive.P0.1 is more sensitive than V1 and （?） because it isindependent of pulmonary mechanics.

Test of incremental respiratory endurance as home-based, standalone therapy in chronic obstructive pulmonary disease: A case report

BACKGROUND The prevalence of chronic obstructive pulmonary disease(COPD)is increasing worldwide,and at the same time it is associated with increased mortality and reduced quality of life.Efforts to build sustainable rehabilitation approaches to COPD treatment and prevention are crucial.The system of long-term pulmonary rehabilitation care is insufficient.The main reasons for the absence of these outpatient programs are the lack of experience,the lack of interest of insurance companies in secondary prevention programs,and the lack of healthcare facilities in large geographical areas.The possibility of at-home pulmonary rehabilitation models(telemonitoring and telecoaching)could solve this problem.CASE SUMMARY A 71-year-old man with severe COPD,Global Initiative for Obstructive Lung Diseases stage 3 underwent an 8-wk remotely monitored inspiratory muscle training with a device based on the test of incremental respiratory endurance method.Spirometry,body plethysmography,test of incremental respiratory endurance examination,6-min walking test,body mass index,airflow obstruction,dyspnea,exercise capacity index,and subjective perception of dyspnea were performed as part of the initial and final examination.The patient performed training at home,and the physiotherapist monitored the patient remotely through a web application that allowed the physiotherapist to evaluate all training parameters in real-time and respond to any problems.After 8 wk of home training,there was a significant increase in all monitored values:maximal inspiratory pressure,a novel parameter sustained maximal inspiratory pressure,forced expiratory volume in 1 s,total lung capacity,forced vital capacity,peak expiratory flow,and inspiratory capacity.There was also an improvement in the perception of dyspnea according to the COPD Assessment Test and a modified Medical Research Council Breathlessness Scale,an increase in exercise tolerance according to the 6-min walking test,and a decrease in the exercise capacity index as a predictor of prognosis.CONCLUSION Respiratory telerehabilitation was greatly beneficial in a cooperative patient with COPD and may represent an alternative therapeutic approach to the increasing incidence of all lung diseases.

Pitfalls in spirometry: Clinical relevance

Spirometry is one of the functional tests most used in respiratory medicine to assess lung function in health and disease conditions.Its success is grounded on solid principles of lung mechanics that state that maximal flow on expiration is limited by the physical properties of airways and lung parenchyma.In contrast,on inspiration,flow depends on the force generated by the inspiratory muscles.Reduced expiratory forced flow and volumes usually reflect a deviation from health conditions.Yet due to a complex interplay of different obstructive and restrictive lung diseases within the multiple structural dimensions of the respiratory system,flows and volumes do not always perfectly reflect the impact of the disease on lung function.The present review is intended to shed light on a series of artefacts and biological phenomena that may confound the clinical interpretation of the main spirometric measurements.Among them is thoracic gas compression volume,the volume and time history of the inspiratory manoeuvre that precedes the forced expiration,the effects of heterogeneous distribution of the disease across the respiratory system,and the changes in lung elastic recoil.

PIP, Not FiO₂Regulates Expression of MMP-9 in the Newborn Rabbit VILI with Different Mechanical Ventilation Strategies

Background: Results from experimental and clinical studies have shown that mechanical ventilation or/and hyperoxia may aggravate a pre-existing lung injury or even cause lung injury in healthy lungs by affecting the expression of MMP-9, but the MMP-9 effects are controversial. How are MMP-9 regulated when multicausative factors of injury such as different FiO2, PIP, and respiratory time (RT) impose simultaneously on lungs? Methods: Newborn New Zealand white rabbits were randomly allocated to an unventilated air control group or to one of the 2 × 3 × 3 ventilation strategies by using a factorial design, with different FiO2, PIP, and RT. Then, lung wet-to-dry ratio (W/D), lung histopathology scores, transmission electron microscope, and cells in BALF were analyzed in these different groups. MMP-9 levels were studied by immunohistochemistry and ELISA. Results: MMP-9 levels were significantly different among 3 PIP ventilation regimes (F = 7.215) and MPIP group was the highest among 3 PIP groups. The lung histopathology score in 100% oxygen was significantly higher than in 45% oxygen group (F = 9.037) and MPIP group was the lowest among 3 PIP groups (F = 57.515) and RT 6 h was more serious than RT 1 h. MMP-9 positively correlated with monocytes, but negatively correlated with neutrophils and lung injury histopathology scores. Conclusions: Different PIP and FiO2 exert simultaneously on newborn lung in newborn rabbits ventilation, only mechanical stretch stimulation affects MMP-9 synthesis. Advisable mechanical stretch can promote MMP-9 expression and has protective role in lung in VILI. HPIP causes barotraumas and LPIP induces atelectrauma.

Relation of Indices of Lung Hyperinflation to Dyspnea in Patients with Chronic Obstructive Pulmonary Disease: A Physiologic Assessment and Discussion

Background: The severity of COPD is commonly assessed by the reduction in forced expiratory volume at one second (FEV1), although more recently prognostic factors influencing survival have also incorporated functional capacity, degree of breathlessness on exertion, and body mass index. Increasingly, the reliability of physiological parameters such as FEV1 to predict patient-centered outcomes has been brought into question. Objectives: To evaluate the relationship between dyspnea as assessed by the Modified Medical Council Dyspnea (MMRC) scale, the Global Initiative for Chronic Obstructive Lung Disease (GOLD 2014) staging and indices of lung hyperinflation and spirometry. Methods: Data were retrospectively analyzed at a 600-bed tertiary care center including spirometry, plethysmographic lung volumes, single breath carbon monoxide diffusion capacity and dyspnea graded according to MMRC, and GOLD staging. Results: Data for 331 patients were analyzed. Differences amongst FEV1, IC, IC/TLC, FRC and RV/TLC were significant between GOLD I/II and GOLD III/IV groups. The closest relationship to GOLD staging was seen with FEV1, FVC and slow vital capacity (SVC). FEV1/FVC, IC, and IC/TLC were inversely associated with MMRC score, while RV/TLC exhibited a positive relation with MMRC score. Conclusions: Indices of lung hyperinflation are closely associated, with dyspnea as assessed by MMRC grading with TLC, RV/TLC and IC exhibiting the closest relations, more so than FEV1. GOLD staging also shows strong correlations with lung volume subdivisions (weakly with TLC), more so than with FEV1. That TLC changed little between GOLD stages can be explained by the presence of collateral interalveolar channels and population characteristics different from those of other studies. These findings further support the concept that more than a reduction in FEV1, lung hyperinflation contributes to the sensation of dyspnea in airflow limitation.

Lung Hyperinflation Is Associated with Pulmonary Exacerbations in Adults with Cystic Fibrosis

Background: Forced expiratory volume 1 second (FEV1) has traditionally been used as a readily available marker of health in adult cystic fibrosis (CF). However, due to the obstructive nature of this disease, it is possible that lung hyperinflation could be more closely related to disease severity than is FEV1. The purpose of this study was to determine if hyperinflation is more closely associated with quality of life, functional status, and pulmonary exacerbations than FEV1 in patients with CF. Methods: Sixty-eight adult patients with CF were evaluated in this retrospective study. We used IC and functional residual capacity (FRC) and their ratios to total lung capacity (TLC) as measures of lung hyperinflation. We used bivariate correlations and backwards regression analysis to assess possible associations between FEV1, lung hyperinflation, and measures of disease severity including questionnaire based quality of life, pulmonary exacerbation frequency, and mortality. The respiratory component of the Cystic Fibrosis Questionnaire–Revised (CRQ-R-Respiratory) was used as a measure of quality of life. Results: Both FEV1 and IC were negatively correlated with pulmonary exacerbations over a 3 year period (p = 0.004, r2 = 0.127;p < 0.001, r2 = 0.307, respectively), while FRC/TLC correlated positively with exacerbations (p = 0.007). Backwards regression analysis showed that among pulmonary function variables, IC had the strongest relationship with exacerbations over 3 years. A lower CFQ-R-Respiratory score was associated with greater mortality (p = 0.005). However, no statistically significant relationships were found between lung function and mortality. Conclusions: FEV1 and lung hyperinflation-as measured by IC and FRC/TLC-are both associated with pulmonary exacerbation frequency. This suggests that chronic dynamic hyperinflation contributes significantly to disease severity in adult cystic fibrosis.

Synchronization of two electrically coupled inspiratory pacemaker neurons

Synchronization is considered to be a crucial mechanism that maintains respiratory rhythm.For understanding the effect of electrical coupling on the transition of the firing patterns and synchronization,we coupled two inspiratory pacemaker neurons together,and studied various synchronous behaviors between them.We firstly compared the bifurcation diagrams between the coupled neurons and single neuron,and found that the coupled neurons had a more complicated bifurcation mode.By increasing the coupling strength,the regular variation of phase differences was illustrated so that asynchronous and some synchronous states could be observed.These synchronous states were also shown in detail by phase portraits and firing series.In addition,we explored the ranges of different synchronous states,which attributed to different ranges of membrane capacitance and coupling strength.

Addition of respiratory exercises to conventional rehabilitation for children and adolescents with cerebral palsy:a systematic review and meta-analysis

Background Respiratory dysfunctions are an important cause of morbidity and death in cerebral palsy(CP)populations.Respiratory exercises in addition to conventional rehabilitation have been suggested to improve respiratory status in CP patients.The objective of this systematic review and meta-analysis was to verify the effects of the addition of respiratory exercises to conventional rehabilitation on pulmonary function,functional capacity,respiratory muscle strength,gross motor function and quality of life in children and adolescents with CP.Methods We searched for randomized controlled clinical trials in PubMed/Medline,Lilacs,SciELO,EMBASE and Physi-otheraphy Evidence(PEDro)from their inception until July 2022 without language restrictions.Studies that included respiratory exercises(breathing exercise program;feedback respiratory training;incentive spirometer exercise;inspiratory muscle training;and combination of respiratory exercises+incentive spirometer exercise)in combination with conventional rehabilitation for children and adolescents with CP were evaluated by two independent reviewers.The mean difference(MD)and 95%confidence interval(CI)were estimated by random effect models.Results Ten studies met the eligibility criteria,including 324 children aged from 6 to 16 years.The meta-analysis showed an improvement in inspiratory muscle strength of 22.96 cmH2O(18.63-27.27,n=55)and pulmonary function of 0.60(0.38-0.82,n=98)for forced vital capacity(L);0.22(0.06-0.39,n=98)for forced expiratory volume at 1 second(L);and 0.50(0.05-0.04,n=98)for peak expiratory flow(L/min).Functional skills in daily living activities improved in the intervention group.Caregivers'assistance of daily living activities,functional capacity,gross motor function and expiratory muscle strength showed a nonsignificant improvement.Social well-being and acceptance and functioning domains improved in only one study.Conclusions Emerging data show significant enhancements in inspiratory muscle strength and pulmonary function in CP patients after respiratory training in addition to conventional rehabilitation.There is no consensus on the frequency,type or intensity of respiratory exercises for children with and adolescents with CP.

Exploiting moderate hypoxia to benefit patients with brain disease: Molecular mechanisms and translational research in progress

Hypoxia is increasingly recognized as an important physiological driving force.A specific transcriptional program,induced by a decrease in oxygen(O2)availability,for example,inspiratory hypoxia at high altitude,allows cells to adapt to lower O2 and limited energy metabolism.This transcriptional program is partly controlled by and partly independent of hypoxia-inducible factors.Remarkably,this same transcriptional program is stimulated in the brain by extensive motor-cognitive exercise,leading to a relative decrease in O2 supply,compared to the acutely augmented O2 requirement.We have coined the term“functional hypoxia”for this important demand-responsive,relative reduction in O2 availability.Functional hypoxia seems to be critical for enduring adaptation to higher physiological challenge that includes substantial“brain hardware upgrade,”underlying advanced performance.Hypoxia-induced erythropoietin expression in the brain likely plays a decisive role in these processes,which can be imitated by recombinant human erythropoietin treatment.This article review presents hints of how inspiratory O2 manipulations can potentially contribute to enhanced brain function.It thereby provides the ground for exploiting moderate inspiratory plus functional hypoxia to treat individuals with brain disease.Finally,it sketches a planned multistep pilot study in healthy volunteers and first patients,about to start,aiming at improved performance upon motor-cognitive training under inspiratory hypoxia.

Neural control of pressure support ventilation improved patient-ventilator synchrony in patients with different respiratory system mechanical properties:a prospective,crossover trial

Background:Conventional pressure support ventilation(PSP)is triggered and cycled off by pneumatic signals such as flow.Patient-ventilator asynchrony is common during pressure support ventilation,thereby contributing to an increased inspiratory effort.Using diaphragm electrical activity,neurally controlled pressure support(PSN)could hypothetically eliminate the asynchrony and reduce inspiratory effort.The purpose of this study was to compare the differences between PSN and PSP in terms of patient-ventilator synchrony,inspiratory effort,and breathing pattern.Methods:Eight post-operative patients without respiratory system comorbidity,eight patients with acute respiratory distress syndrome(ARDS)and obvious restrictive acute respiratory failure(ARF),and eight patients with chronic obstructive pulmonary disease(COPD)and mixed restrictive and obstructive ARF were enrolled.Patient-ventilator interactions were analyzed with macro asynchronies(ineffective,double,and auto triggering),micro asynchronies(inspiratory trigger delay,premature,and late cycling),and the total asynchrony index(AI).Inspiratory efforts for triggering and total inspiration were analyzed.Results:Total AI of PSN was consistently lower than that of PSP in COPD(3%vs.93%,P=0.012 for 100%support level;8%vs.104%,P=0.012 for 150%support level),ARDS(8%vs.29%,P=0.012 for 100%support level;16%vs.41%,P=0.017 for 150%support level),and post-operative patients(21%vs.35%,P=0.012 for 100%support level;15%vs.50%,P=0.017 for 150%support level).Improved support levels from 100%to 150%statistically increased total AI during PSP but not during PSN in patients with COPD or ARDS.Patients’inspiratory efforts for triggering and total inspiration were significantly lower during PSN than during PSP in patients with COPD or ARDS under both support levels(P<0.05).There was no difference in breathing patterns between PSN and PSP.Conclusions:PSN improves patient-ventilator synchrony and generates a respiratory pattern similar to PSP independently of any level of support in patients with different respiratory system mechanical properties.PSN,which reduces the trigger and total patient’s inspiratory effort in patients with COPD or ARDS,might be an alternative mode for PSP.Trial Registration:ClinicalTrials.gov,NCT01979627;https://clinicaltrials.gov/ct2/show/record/NCT01979627.