Evaluation of the therapeutic efficacy and tolerability of current drug treatments on the clinical outcomes of paediatric spinal muscular atrophy type 1: A systematic review.

Spinal muscular atrophy (SMA) is a severe hereditary lower motor neuron disorder characterised by degeneration of alpha motor neurons in the spinal cord, resulting in progressive weakness and paralysis of proximal muscles. A systematic literature search was carried out by using PRISMA guidelines and searching through different databases that could provide findings of evidence on the health outcomes of the approved therapies for the management of paediatric SMA type 1 regarding efficacy with follow-up in terms of motor and respiratory functions and the tolerability and incidence of adverse drug reactions (ADRs) post-treatment from real-world publications. Half of the publications (50%) had a prospective observational design. Eight studies (66.7%) assessed nusinersen, and three studies (25%) assessed onasemnogene abeparvovec with a duration of follow-up ranging from 6 months to 3 years to evaluate the motor and respiratory functions using different assessment tools, hospitalisation rates, and the tolerability and incidence of ADRs post-treatment. The three currently approved treatments for SMA type 1 provided good support and health outcomes in terms of motor function, respiratory outcomes, reduction of hospitalisations, and improvement of survival. Nevertheless, uncertainties regarding continued improvement after long-term illness and the generalizability of results are still unknown.

Clinical determinants of sleep quality in patients with amyotrophic lateral sclerosis.

OBJECTIVES: Poor sleep quality is more prevalent in patients with amyotrophic lateral sclerosis (ALS) than in healthy populations. The purpose of this study was to examine whether or not motor dysfunction at various distinct levels correlates with subjective sleep quality. METHODS: Patients with ALS and controls were assessed using the Pittsburgh Sleep Quality Index (PSQI), ALS Functional Rating Scale Revised (ALSFRS-R), Beck Depression Inventory-II (BDI-II), and the Epworth Sleepiness Scale (ESS). The ALSFRS-R was used to obtain information on 12 different aspects of motor function in patients with ALS. We compared these data between the groups with poor and good sleep quality. RESULTS: A total of 92 patients with ALS and 92 age- and sex-matched controls entered the study. The global PSQI score was significantly higher in patients with ALS than in healthy subjects (5.5 ± 4.2 vs. 4.0 ± 2.8) and 44% of the patients with ALS had poor sleep quality (PSQI score > 5). The sleep duration, sleep efficiency, and sleep disturbances components were significantly worse in patients with ALS. Sleep quality (PSQI) score correlated with ALSFRS-R score, BDI-II score, and ESS score. Of the 12 ALSFRS-R functions, swallowing significantly affected sleep quality. Orthopnea, speech, salivation, dyspnea, and walking had a medium effect. In addition, turning in bed, climbing stairs, and dressing and hygiene were found to have a small effect on sleep quality among patients with ALS. CONCLUSIONS: Nearly half of our patients had poor sleep quality related to disease severity, depression, and daytime sleepiness. Bulbar muscle dysfunction may be associated with sleep disturbances in individuals with ALS, particularly when swallowing is impaired. In addition, patients suffering from axial or lower limb muscle disruptions are likely to have trouble sleeping.

Airway microbiome is associated with respiratory functions and responses to ambient particulate matter exposure.

BACKGROUND: Ambient particulate matter (PM) exposure has been associated with respiratory function decline in epidemiological studies. We hypothesize that a possible underlying mechanism is the perturbation of airway microbiome by PM exposure. METHODS: During October 2016-October 2017, on two human cohorts (n = 115 in total) in Shanghai China, we systematically collected three categories of data: (1) respiratory functions, (2) airway microbiome from sputum, and (3) PM2.5 (PM of ≤ 2.5 µm in diameter) level in ambient air. We investigated the impact of PM2.5 on airway microbiome as well as the link between airway microbiome and respiratory functions using linear mixed regression models. RESULTS: The respiratory function of our primary interest includes forced vital capacity (FVC) and forced expiratory volume in 1st second (FEV1). FEV1/FVC, an important respiratory function trait and key diagnosis criterion of COPD, was significantly associated with airway bacteria load (p = 0.0038); and FEV1 was associated with airway microbiome profile (p = 0.013). Further, airway microbiome was significantly influenced by PM2.5 exposure (p = 4.48E-11). CONCLUSIONS: To our knowledge, for the first time, we demonstrated the impact of PM2.5 on airway microbiome, and reported the link between airway microbiome and respiratory functions. The results expand our understanding on the scope of PM2.5 exposure's influence on human respiratory system, and point to novel etiological mechanism of PM2.5 exposure induced diseases.

Prediction of COPD and Related Events Improves by Combining Spirometry and the Single Breath Nitrogen Test.

Chronic obstructive pulmonary disease (COPD) develops in small airways. Severity of small airway pathology relates to progression and mortality. The present study evaluated the prediction of COPD of a validated test for small airway disease, i.e. a slope of the alveolar plateau of the single breath nitrogen test (N2-slope). The N2-slope, spirometry, age, smoking habits, and anthropometric variables at baseline were obtained in a population-based sample (n = 592). The cohort was followed for first COPD events (first hospital admission of COPD or related conditions or death from COPD) during 38 years. During follow-up, 52 subjects (8.8%) had a first COPD event, of which 18 (3.0%) died with a first COPD diagnosis. In the proportional hazard regression analysis adjusted for age and smoking habits, the cumulative COPD event incidence increased from 5% among those with high forced expired volume in one second (FEV1) to 25% among those with low FEV1, while increasing from 4% among those with the lowest N2-slope to 26% among those with the highest. However, combining the N2-slope and FEV1 resulted in considerable synergy in the prediction of first COPD event and even more so when taking account of smoking habits. The cumulative COPD event incidence rate was 75% among heavy smokers with the highest N2-slope and lowest FEV1, and less than 1% among never smokers with the lowest N2-slope and highest FEV1. Thus, combining the results of the single breath N2-slope and FEV1 considerably improved the prediction of COPD events as compared to either test alone.

The effect of expiratory muscle strength training on the oral and respiratory functions of community-dwelling older people: An analysis using the swallowing, oral, phonatory, and respiratory muscle function indices.

PURPOSE: This study was performed to determine the effects of expiratory muscle strength training (EMST) on the oral and respiratory functions of community-dwelling older people. METHODS: Older people using a visiting-rehabilitation center were divided into an intervention group of 31 subjects and a control group of 15 subjects. Those in the intervention group were assigned home training for 8 weeks, which included 5 sets of 5 breaths per day with a 75% load of the maximum expiratory pressure using an EMST device. The outcome indices included (1) oral functions, evaluated by the cumulative time spent swallowing three times and the maximum phonation time (MPT) and (2) respiratory functions, evaluated by the maximum expiratory pressure and maximum inspiratory pressure (MEP/MIP). An independent t-test and paired t-test were used to analyze the data. RESULTS: The cumulative time spent swallowing three times was lower in the intervention group than in the control group. This difference remained significant even after adjusting for sex, age, and baseline values. The MPT was 2.1 seconds higher than baseline in the intervention group but 0.4 seconds lower than baseline in the control group. An average increase of 5.7 cmH2O in the PEmax was observed in the intervention group compared with an average decrease of 4.6 cmH2O in the control group, indicating a significant difference. CONCLUSION: These results suggest that EMST improves the oral and respiratory functions of community elderly subjects. This may be explained by the fact that the pathway for swallowing is partially shared with that for phonation, which contributes to a shortened swallowing time by repeated suprahyoid muscle contractions.

Sleep and breathing disorders in myotonic dystrophy type 2.

OBJECTIVES: In patients who exhibit myotonic dystrophy type 1 (DM1), sleep disorders and breathing impairments are common; however, in those with DM type 2 (DM2), limited studies on polysomnography (PSG) and none on phrenic compound motor action potential (CMAP) have been performed, which is the aim of this study. MATERIALS AND METHODS: Sixteen patients with DM2 were questioned about respiratory symptoms. They underwent PSG with morning arterial gas analyses (AGA). Respiratory functions and phrenic CMAPs were studied. The data were compared to those of 16 healthy controls and 25 patients with DM1. RESULTS: Daytime tiredness is the most common symptom, but orthopnea was reported in 13% of patients with DM2. A detailed sleep architecture analysis revealed a significantly greater proportion of time in stage 3 and REM sleep, and a shorter time in stage 2 in the DM2 than in controls. Lower respiratory volumes and pressures, abnormalities in AGA, night oxygen desaturation and higher EtCO2 are present in DM2, but are less pronounced than in the DM1 population. Small CMAP amplitudes were presented in 12% of patients with DM2, correlating with smaller respiratory functions and poorer sleep quality. AHI was abnormal in 38% of DM2, mainly due to obstructive apneas. PSG did not reveal hypoventilation. CONCLUSIONS: Diaphragm weakness and sleep apneas might be present in patients with DM2; therefore, we suggest regular questioning about symptoms of respiratory insufficiency and monitoring of phrenic CMAP. PSG should be recorded, when patients have suggestive symptoms, abnormalities in AGA or higher BMI.

Obesity-related reduced spirometry and altered breathing pattern are associated with mechanical disadvantage of the diaphragm.

The aim of this study was to characterize the breathing patterns of individuals with obesity during routine activities such as sitting and standing, and to identify potential contributors to alterations in these patterns. Measurements performed in 20 male subjects with obesity (BMI, 31.8±1.5 kg/m2) and 20 controls (BMI, 23.5±1.4 kg/m2) included anthropometric parameters, breathing-patterns in sitting and standing positions, spirometry, maximal respiratory pressures, and diaphragm B-mode ultrasonography. Individuals with obesity exhibited lower tidal volume and increased respiratory rate to maintain a similar minute-ventilation (p<0.05). Subjects with obesity demonstrated impaired spirometry and respiratory muscle strength, with inspiratory functions being notably compromised (p<0.05). Individuals with obesity had a greater diaphragm thickness at end inspiration but lower thickening-fraction at end quiet and forced breathings and reduced diaphragmatic displacement and excursion during maximal breaths (p<0.05). BMI was negatively associated with all respiratory function markers (p<0.05). Individuals with obesity exhibit a higher respiratory rate but lower tidal volume, likely to accommodate decreased compliance and excess thoracic and abdominal fat, further hindering inspiratory function. Moreover, increased adiposity is associated with a thicker but weaker diaphragm, primarily due to the diaphragm's mechanical disadvantage rather than its intrinsic inability to generate force.

Multiomic characterisation of the long-term sequelae of SARS survivors: a clinical observational study.

Background: We aimed to characterise the long-term health outcomes of survivors of severe acute respiratory syndrome (SARS) and determine their recovery status and possible immunological basis. Methods: We performed a clinical observational study on 14 health workers who survived SARS coronavirus infection between Apr 20, 2003 and Jun 6, 2003 in Haihe Hospital (Tianjin, China). Eighteen years after discharge, SARS survivors were interviewed using questionnaires on symptoms and quality of life, and received physical examination, laboratory tests, pulmonary function tests, arterial blood gas analysis, and chest imaging. Plasma samples were collected for metabolomic, proteomic, and single-cell transcriptomic analyses. The health outcomes were compared 18 and 12 years after discharge. Control individuals were also health workers from the same hospital but did not infect with SARS coronavirus. Findings: Fatigue was the most common symptom in SARS survivors 18 years after discharge, with osteoporosis and necrosis of the femoral head being the main sequelae. The respiratory function and hip function scores of the SARS survivors were significantly lower than those of the controls. Physical and social functioning at 18 years was improved compared to that after 12 years but still worse than the controls. Emotional and mental health were fully recovered. Lung lesions on CT scans remained consistent at 18 years, especially in the right upper lobe and left lower lobe lesions. Plasma multiomics analysis indicated an abnormal metabolism of amino acids and lipids, promoted host defense immune responses to bacteria and external stimuli, B-cell activation, and enhanced cytotoxicity of CD8+ T cells but impaired antigen presentation capacity of CD4+ T cells. Interpretation: Although health outcomes continued to improve, our study suggested that SARS survivors still suffered from physical fatigue, osteoporosis, and necrosis of the femoral head 18 years after discharge, possibly related to plasma metabolic disorders and immunological alterations. Funding: This study was funded by the Tianjin Haihe Hospital Science and Technology Fund (HHYY-202012) and Tianjin Key Medical Discipline (Specialty) Construction Project (TJYXZDXK-063B, TJYXZDXK-067C).

Pulmonary functions and anthropometric parameters of young male and female adults participating in moderate aerobic exercise.

Respiratory disorders may be one of the adverse effects of sedentary lifestyle. This study investigated respiratory functions (FEV1, FVC and PEFR) and anthropometric parameters (body weight and body mass index) of healthy young males and females participating in moderate aerobic exercise. Forty young healthy untrained non-athletes, twenty males and twenty females (age, 25 ± 5.6 years; body weight, 65 ± 4.0 kg; body height, 176.9 ± 2.5 cm) volunteered to participate in this study. The exercise regimen was of moderate intensity lasting for 20 min daily on a treadmill consistently at the speed of 13 km/h for 14 days. The weight and height of participants were measured using medical scale and wall-mounted stadiometer respectively. The forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) were assessed using digital spirometer. The results showed a significant (p < 0.05) decrease in body weight and body mass index of female participants after 14 days of exercise regimen. The FEV1, FVC and PEFR were significantly increased (p < 0.05) in both male and female subjects after exercise. The Pearson correlation showed a significant (p < 0.05) positive correlation between BMI with FEVI/FVC% in female participants. There was an increase in calories burnt from day 4 of the study in both male and female participants. It is concluded that moderate aerobic exercise improved respiratory functions (FEV1, FVC and PEFR) in both male and female subjects with greater improvement in females while reducing body weight and body mass index in females.

Effects of Inspiratory Muscle Training on Respiratory Muscle Strength, Trunk Control, Balance and Functional Capacity in Stroke Patients: A single-blinded randomized controlled study.

OBJECTIVE: Aim of the study was to examine the effects of inspiratory muscle training (IMT) on respiratory function, respiratory muscle strength, trunk control, balance, and functional capacity in stroke patients. METHODS: 21 stroke individuals were randomly divided into two groups as control group and treatment group. Respiratory function test, Maximal Inspiratory Pressure (MIP) and Maximal Expiratory Pressure (MEP) were evaluated. Also, Trunk Impairment Scale (TIS), Timed Up and Go Test (TUG) Berg Balance Scale (BBS), and Six-Minute Walk Test (6MWT) were performed. Neurodevelopmental treatment program was performed in both groups for 5 days a week for 6 weeks, and IMT was given to the treatment group. IMT was started from 40% of MIP. RESULTS: After treatment, respiratory functions, respiratory muscle strength, and trunk control and balance improved in the treatment group. In the control group; however, only the balance level was improved. When the changes in the evaluation parameters between the groups were compared, there were only statistically significant differences in the TIS, Peak Expiratory Flow (PEF) and MIP in the treatment group (p˂0.05), the change amounts in other evaluation parameters were similar (p˃0.05). When the effect size of the groups was compared, the effect size of the variables in the treatment group was found to be higher. CONCLUSION: As a conclusion, IMT, which was given in addition to the neurological physiotherapy and rehabilitation program to our patients, improved inspiratory muscle strength and trunk control. We believe that this result will raise awareness for physiotherapists working in the field of neurological rehabilitation about including respiratory muscle training in the rehabilitation program of stroke patients.

Within- and cross-tissue gene regulations were disrupted by PM2.5 nitrate exposure and associated with respiratory functions.

BACKGROUND: Pathogenesis of complex diseases often involves multiple organs/tissue-types. To date, the PM2.5 exposure's toxic effects and induced disease risks were not studied at multi-tissue level. METHODS: C57BL/6 mice (n = 40) were exposed to PM2.5 NO3- and clean air, respectively, and afterwards assessed respiratory functions and transcriptome in relevant tissues: blood and lung. We constructed within- and cross-tissue gene regulation networks and identified network modules associated with exposure and respiratory functions. RESULTS: PM2.5 NO3- exposure elevated naïve B cells proportion in blood (p = 0.0028). Among the 6000 highest expressed genes in blood, 18.8 % (1133 genes) were altered by exposure at p ≤ 0.05 level, among which 763 genes were also associated with respiratory function (enrichment folds = 7.63, p = 2.7E-189). The exposure disrupted blood genes were primarily in the immunoregulation pathways. Both within- and cross-tissue gene network modules were perturbed by exposure and associated with respiratory function. An immunodeficiency related cross-tissue module of 555 genes was affected by exposure (p = 0.0023) and strongly correlated with FEV0.05/FVC (r = 0.61 and p = 3E-5). CONCLUSIONS: This study aims to fill in a major knowledge gap and investigated the effect of PM2.5 exposure simultaneously in multiple tissues. We provided novel evidence that PM2.5 NO3- exposure profoundly perturbed within- and cross-tissue gene regulations, and highlighted their roles in the etiology of respiratory decline.

The relationships between isometric muscle strength and respiratory functions of the Turkish National Paralympic Goalball Team.

Goalball is a unique sport for only blind and visually disabled people to prevent physical inactivity and its harmful consequences. Determining the profile of physical fitness parameters and their relationship is crucial for all sports discipline. The purpose of the study is to determine the characteristics and the relationship between isometric muscle strength and respiratory functions. A total of 14 (10 female, four male athletes) goalball athletes were included in the study. Upper-extremity, lower-extremity and trunk isometric muscle strength and pulmonary function tests measurements were performed to the athletes on two different days. The relationship between parameters was evaluated by Spearman correlation test. Strength and pulmonary function parameters were higher in male athletes (P<0.05). A medium/strong/very strong correlation was found between respiratory function and upper extremity isometric muscle strength (r=0.529-0.917, P<0.05). A moderate/strong correlation was found between lower extremity isometric muscle strength and respiratory function (r=0.534-0.867, P<0.05). A moderate correlation was found between trunk isometric muscle strength and respiratory function (r=0.538-0.640, P<0.05). It was seen that respiratory functions were associated with upper-lower extremity and trunk muscle strength. With this result, the idea arises that strength exercises can affect the improvement of respiratory function in individuals with disabilities, which is very important for both overall health and sports performance.

Respiratory function in children with nephrotic syndrome: Comparative evaluation of impulse oscillometry and spirometry.

AIM: To evaluate the respiratory functions of children with nephrotic syndrome (NS) by impulse oscillometry (IOS) and its correlation with spirometry. METHODS: Fifty-five NS patients aged 3-18 years were included as the study group and 40 healthy children of the same age formed the control group. Patients were divided into nephrotic phase (first attack and relapse) and remission. Demographic, anthropometric, and laboratory data of the children were recorded. Respiratory functions were evaluated by IOS and spirometry. Children over 6-years old performed both IOS and spirometry while children under 6 years performed only IOS. RESULTS: The R (R5%, R10%, R5-20), AX and Z5% values of IOS in patients with nephrotic phase were higher than remission patients and control group while spirometry indices of PEF% and MEF25-75% were lower. Z scores of MEF25-75 were significantly negatively correlated with z scores of R5, R10, Z5, and Fres while they were significantly positively correlated with z scores of X values (5, 10, 15, and 20 Hz). Z scores of forced expiratory volume in 1 /forced vital capacity significantly negatively correlated with z scores of R values (R5, R10), Z5 and AX and positively correlated with z scores of X values (X5, X10, X15 Hz). CONCLUSION: Our study demonstrated that respiratory functions measured by IOS and spirometry were affected at the time of nephrotic phase in NS patients. IOS, a novel method easily applicable even in small children, is a potentially valuable tool to detect this condition; given its good correlation with spirometry.

The relationship between dysphagia, respiratory functions and anthropometry in patients with multiple sclerosis.

BACKGROUND: It is known that many body systems are affected as a result of dysphagia. The aim of this study is to investigate the relationship between clinical features, respiratory functions, anthropometric measurements and dysphagia in patients with multiple sclerosis (MS). METHOD: Seventy-five MS patients and 50 healthy controls were included in this prospective case-control study. Disability was assessed with expanded disability status scale (EDSS), and swallowing was assessed with questionnaire for the assessment of dysphagia (solid, liquid and total) for disease. Respiratory functions were demonstrated with computerized spirometry device. Body weight, height, waist, hip, and mid-arm circumference are measured. Body mass index and body fat percentage were calculated. The relationship of all these parameters with disease activity and dysphagia was investigated. RESULTS: There were 75 MS patients with a mean age of 38.40 ± 11.27 years, and 50 (66.70%) were female in the study. The all type of dysphagia scores were higher in MS patients than control group (p = 0.001). Many respiratory function test scores and only hip circumference were lower in MS patients. However, especially low forced expiratory volume-1st second (FEV1), forced vital capacity (FVC) and peak expiratory flow (PEF) values were associated with disability. In addition, dysphagia scores were higher in progressive MS patients with severe disability and high frequency attacks (p = 0.001). Increased severity of dysphagia are associated with many lower anthropometric measurements (not height-especially mid-arm circumference) and respiratory function test scores. CONCLUSION: MS affects swallowing and respiratory systems functions. They are associated with MS disease activity. Dysphagia and its severity are associated with many anthropometric measurements and respiratory functions test scores.

Long Term Respiratory Follow-Up for COVID-19 Patients a Multicenter Study.

BACKGROUND: The first wave of the COVID-19 pandemic initiated officially in October 2020. Since then several observations have been made regarding the disease and its symptoms. PATIENTS AND METHODS: We included eighty seven in our observational study. Our main aim was to investigate their long term respiratory follow-up in correlation with their initial radiological and laboratory findings and values. The nose swab PCR test for COVID-19 was used for diagnosis. Patients were monitored at 3 and 6 months after their hospital reception whereas basic parameters of health condition (smoking, PO2, SPO2, WBC, CXR, CRP, intercurrent findings, days of nursing, colchicine administration) in joint with gender and age were recorded. RESULTS: Males seem more susceptible to the viral disease than females in a ratio 1,8:1. The parameters FEV1 and FVC (as % relative changes) were not affected, apart from the DLCO to which CRP (in loge+1 transformation) and SPO2 showed a statistically significant effect. CONCLUSION: None of these patients were intubated, or admitted to the intensive care unit. The respiratory function is affected by the virus and the effect is reversed within the first three months. Males are more affected and the radiological and laboratory findings are associated with the respiratory functions.

Comparative study on respiratory function among rural women using biomass fuel and non-biomass fuel: evidence of a cross-sectional survey in Bangladesh.

Respiratory diseases' mortality and morbidity have been a major public health burden primarily attributed to widespread exposure to indoor and outdoor pollutants in the environment. The study conducted among 510 Bangladeshi women residing in the northeastern zone of the Sylhet division from semi-urban and rural settings to compare the biomass fuel users (N = 255) with the non-biomass users (N = 255). It has been observed that all the symptoms had a higher prevalence among the women who were exposed to biomass fuel compared with those exposed to clean gas fuel. Women exposed to biomass group reported frequent cough and phlegm production episodes during a 3-month timeline before the survey period which was found statistically higher (p < 0.001) compared with that of the clean gas fuel group. Moreover, the use of biomass fuel has been associated with a significant decrease in forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow rate (PEFR). Appropriate strategies from stakeholders and government authorities in disseminating health hazards from biomass fuel along with supporting the community by providing alternative energy sources for cooking can largely impact people's lives.

Evaluation of respiratory functions and quality of life in multiple sclerosis patients.

The aim of this study was to evaluate respiratory muscle strength, respiratory functions and quality of life in multiple sclerosis (MS) patients and compare the results with the healthy volunteers. The study included a group of 24 patients diagnosed with MS (16 women, 8 men) with an EDSS score of ≤ 5, who were without clinical respiratory impairment. MS patients were compared with the healthy volunteer group (16 women, 8 men). Respiratory muscle strength and respiratory functions were evaluated with specific devices. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) parameters were measured for the muscle strength. Forced vital capacity (FVC), forced expiratory volume (FEV1), FEV1/FVC, peak expiratory flow, and forced expiratory flow (FEF25-75) parameters were measured for the respiratory functions. Questionnaire SF-36 was applied to evaluate health-related quality of life. A total of 24 MS patients' respiratory function test results were compared with healthy volunteers and significant changes were found at MIP, MEP, and FEV1 parameters. Quality of life was compared between the groups and there was a significant difference in parameters related with physical performance and physical-health-related role limitations. There is an early involvement of the respiratory muscles in patients with MS, yet clinical symptoms appear in later stages. Respiratory functions should be evaluated at the earlier stage of the disease so that rehabilitation can be planned in order to reduce respiratory complications and improve the quality of life in patients.

Impact of delivered tidal volume on the occurrence of intraventricular haemorrhage in preterm infants during positive pressure ventilation in the delivery room.

BACKGROUND AND OBJECTIVES: Delivery of inadvertent high tidal volume (VT) during positive pressure ventilation (PPV) in the delivery room is common. High VT delivery during PPV has been associated with haemodynamic brain injury in animal models. We examined if VT delivery during PPV at birth is associated with brain injury in preterm infants <29 weeks' gestation. METHODS: A flow-sensor was placed between the mask and the ventilation device. VT values were compared with recently described reference ranges for VT in spontaneously breathing preterm infants at birth. Infants were divided into two groups: VT<6 mL/kg or VT>6 mL/kg (normal and high VT, respectively). Brain injury (eg, intraventricular haemorrhage (IVH)) was assessed using routine ultrasound imaging within the first days after birth. RESULTS: A total of 165 preterm infants were included, 124 (75%) had high VT and 41 (25%) normal VT. The mean (SD) gestational age and birth weight in high and normal VT group was similar, 26 (2) and 26 (1) weeks, 858 (251) g and 915 (250) g, respectively. IVH in the high VT group was diagnosed in 63 (51%) infants compared with 5 (13%) infants in the normal VT group (P=0.008).Severe IVH (grade III or IV) developed in 33/124 (27%) infants in the high VT group and 2/41 (6%) in the normal VT group (P=0.01). CONCLUSIONS: High VT delivery during mask PPV at birth was associated with brain injury. Strategies to limit VT delivery during mask PPV should be used to prevent high VT delivery.

Metabolic heat production and evaporation of poultry.

Accurate measurements of gas exchange between an animal and its environment is critical in determining metabolic heat production and respiratory functions of broilers. Information on non-invasive methods to measure gas exchange of broiler chicks and chickens under uncontrolled environmental conditions is lacking in the literature. The aims of this study were: (1) to develop an indirect calorimetric system including a hood that allows gas exchange for chickens, (2) to measure gas exchange and respiratory functions (respiration rate, ventilation rate, and tidal volume) of broiler chickens weighing greater than 250 g, and (3) to calculate heat production and respiratory evaporation of the birds based on measured gas and vapor exchanges. We conducted two trials. The first trial involved 6 broiler chicks evaluated for 6 days in 6 different schedules (6 × 6 Latin square). The chicks were kept inside a heat exchanger with a continuous air flow of 150 mL min-1. The second trial involved 12 birds evaluated for 12 days in 12 different schedules (12 × 12 Latin square). Metabolic heat production and evaporation were influenced by live weight of chicks, varying between evaluation days (P < 0.05). The respiratory functions (tidal volume, ventilation rate, and respiratory rate) varied between days, and were strongly influenced by live weight of the broilers (P < 0.05).