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Journal of Intensive Care Medicine Jun 2021Many patients with coronavirus disease 2019 (COVID-19) need mechanical ventilation secondary to acute respiratory distress syndrome. Information on the respiratory...
OBJECTIVE
Many patients with coronavirus disease 2019 (COVID-19) need mechanical ventilation secondary to acute respiratory distress syndrome. Information on the respiratory system mechanical characteristics of this disease is limited. The aim of this study is to describe the respiratory system mechanical properties of ventilated COVID-19 patients.
DESIGN, SETTING, AND PATIENTS
Patients consecutively admitted to the medical intensive care unit at the University of Iowa Hospitals and Clinics in Iowa City, USA, from April 19 to May 1, 2020, were prospectively studied; final date of follow-up was May 1, 2020.
MEASUREMENTS
At the time of first patient contact, ventilator information was collected including mode, settings, peak airway pressure, plateau pressure, and total positive end expiratory pressure. Indices of airflow resistance and respiratory system compliance were calculated and analyzed.
MAIN RESULTS
The mean age of the patients was 58 years. 6 out of 12 (50%) patients were female. Of the 21 laboratory-confirmed COVID-19 patients on invasive mechanical ventilation, 9 patients who were actively breathing on the ventilator were excluded. All the patients included were on volume-control mode. Mean [±standard deviation] ventilator indices were: resistive pressure 19 [±4] cmHO, airway resistance 20 [±4] cmHO/L/s, and respiratory system static compliance 39 [±16] ml/cmHO. These values are consistent with abnormally elevated resistance to airflow and reduced respiratory system compliance. Analysis of flow waveform graphics revealed a pattern consistent with airflow obstruction in all patients.
CONCLUSIONS
Severe respiratory failure due to COVID-19 is regularly associated with airflow obstruction.
Topics: Adult; Aged; Airway Obstruction; Airway Resistance; COVID-19; Cohort Studies; Critical Care; Female; Humans; Male; Middle Aged; Pulmonary Ventilation; Respiration, Artificial; Respiratory Distress Syndrome
PubMed: 33706592
DOI: 10.1177/08850666211000601 -
American Journal of Physiology. Lung... May 2022Lung resistance () and elastance () can be measured during positive or negative pressure ventilation. Whether the different modes of ventilation produce different and...
Lung resistance () and elastance () can be measured during positive or negative pressure ventilation. Whether the different modes of ventilation produce different and is still being debated. Although negative pressure ventilation (NPV) is more physiological, positive pressure ventilation (PPV) is more commonly used for treating respiratory failure. In the present study, we measured lung volume, airway diameter, and airway volume, as well as and with PPV and NPV in explanted sheep lungs. We found that lung volume under a static pressure, either positive or negative, was not different. However, and were significantly higher in NPV at high inflation pressures. Interestingly, diameters of smaller airways (diameters <3.5 mm) and total airway volume were significantly greater at high negative inflation pressures compared with those at high positive inflation pressures. This suggests that NPV is more effective in distending the peripheral airways, likely due to the fact that negative pressure is applied through the pleural membrane and reaches the central airways via the peripheral airways, whereas positive pressure is applied in the opposite direction. More distension of lung periphery could explain why is higher in NPV (vs. PPV), because the peripheral parenchyma is a major source of tissue resistance, which is a part of the that increases with pressure. This explanation is consistent with the finding that during high frequency ventilation (>1 Hz, where reflects airway resistance more than tissue resistance), the difference in between NPV and PPV disappeared.
Topics: Airway Resistance; Animals; Lung; Positive-Pressure Respiration; Respiratory Function Tests; Respiratory Mechanics; Respiratory Physiological Phenomena; Sheep
PubMed: 35272489
DOI: 10.1152/ajplung.00464.2021 -
Hawai'i Journal of Health & Social... Mar 2022Causes of the extraordinarily high and increasing incidence of snorkeler drownings in Hawai'i have remained unexplained for years. Defining the mechanisms and factors...
Causes of the extraordinarily high and increasing incidence of snorkeler drownings in Hawai'i have remained unexplained for years. Defining the mechanisms and factors predisposing to drowning while snorkeling is needed to provide recommendations to substantially mitigate the incidence of this form of preventable death. The mechanisms of drowning are described and insight into the predisposing factors are explored in this study. Methods included measuring snorkel airway resistance characteristics, case reports from the State of Hawai'i Medical Examiner's office, and collating information by survey, principally from rescued survivors. This study identified 2 modes of drowning while snorkeling that need further investigation: accidental or inadvertent aspiration, and hypoxia resulting from acute negative pressure pulmonary edema. The incidence of drowning from mechanisms of hypoxia due to rapid onset pulmonary edema is an important focus of the study and a number of potentially significant predisposing factors are presented that need further investigation but provide bases that may become part of updated policies and practices for snorkelers to substantially lower the risk of death. This report is meant for both medical and public health information purposes.
Topics: Drowning; Hawaii; Humans; Hypoxia; Incidence; Pulmonary Edema
PubMed: 35261987
DOI: No ID Found -
Journal of Healthcare Engineering 2022To investigate the effect of AutoFlow on airway pressure and hemodynamics in mechanical ventilation constant volume-control ventilation mode, 100 patients receiving... (Randomized Controlled Trial)
Randomized Controlled Trial
To investigate the effect of AutoFlow on airway pressure and hemodynamics in mechanical ventilation constant volume-control ventilation mode, 100 patients receiving mechanical ventilation were randomly divided into observation group (SIMV-PSV-PEEP + AutoFlow) and control group (SIMV-PSV-PEEP). The results showed that the peak airway pressure and average airway pressure decreased with different flow rate settings and automatic flow conversion ( < 0.05). The peak airway pressure and mean airway pressure decreased with different resistance settings ( < 0.05). With different compliance settings, the peak airway pressure and average airway pressure decreased after being assisted with an automatic converter ( < 0.05). Adding AutoFlow on the basis of SIMV-PSV mode can significantly reduce peak inspiratory pressure (PIP), mean airway pressure (P), and airway resistance (R). There was no significant difference in hemodynamic monitoring results between the observation group and the control group. It is proved that the SIMV constant volume-controlled ventilation mode combined with AutoFlow can not only ensure tidal volume but also avoid excessive airway pressure, which has little effect on hemodynamics.
Topics: Hemodynamics; Humans; Respiration, Artificial; Technology; Thoracic Surgery; Tidal Volume
PubMed: 35388321
DOI: 10.1155/2022/2507149 -
The Role of Myofunctional Therapy in Treating Sleep-Disordered Breathing: A State-of-the-Art Review.International Journal of Environmental... Jul 2021Myofunctional therapy (MFT) may have a role in improving muscle tone and alleviating upper airway collapse in sleep-disordered breathing. The purposes of this... (Review)
Review
Myofunctional therapy (MFT) may have a role in improving muscle tone and alleviating upper airway collapse in sleep-disordered breathing. The purposes of this state-of-the-art review are to first review systematically the current literature on the effectiveness of MFT in treating sleep-disordered breathing and then to provide an overview of the current understanding of patient selection, side effects, type and duration of exercises, guidance of exercise performance, evaluation of results, and how best to promote adherence. PubMed (Medline), the Cochrane Library, and the EMBASE, Scopus and SciELO databases were checked for relevant studies by three authors, and a total of 23 studies were included. This review focuses only on adults with sleep-disordered breathing. The available evidence shows a positive effect of MFT in reducing sleep apnoea, as measured using polysomnography and clinical variables (including snoring). There is no evidence of the utility of MFT for treating upper airway resistance syndrome, the duration of the effects of MFT, or regarding which MFT protocol is best. Despite these knowledge gaps, the available evidence suggests that MFT is a safe treatment modality.
Topics: Adult; Humans; Myofunctional Therapy; Polysomnography; Sleep Apnea Syndromes; Sleep Apnea, Obstructive; Snoring
PubMed: 34299742
DOI: 10.3390/ijerph18147291 -
Journal of Applied Physiology... Jan 2021The obesity epidemic is causing a rise in asthma incidence due to the appearance of an obesity-specific late-onset nonallergic (LONA) phenotype. We investigated why only...
The obesity epidemic is causing a rise in asthma incidence due to the appearance of an obesity-specific late-onset nonallergic (LONA) phenotype. We investigated why only a subset of obese participants develop LONA asthma by determining how obesity, both alone and in combination with LONA asthma, affects the volume dependence of respiratory system impedance. We also determined how obesity and asthma affect impedance during and following challenge with the PC dose of methacholine. We found during passive exhalation that all obese participants, in contrast to lean controls and lean asthmatics, experienced similarly profound elevations in lung elastance as they approached functional residual capacity. We also found, however, that the LONA asthmatics had a greater negative dependence of airway resistance on lung volume over the middle of the volume range compared with the other groups. Methacholine challenge with the PC dose led to comparable changes in respiratory system impedance in the four study groups, but the doses themselves were substantially lower in both obese and lean asthmatic participants compared with obese and lean controls. Also, the obese LONA asthmatics had higher breathing frequencies and lower tidal volumes postchallenge compared with the other participants. Taken together, these results suggest that all obese individuals experience substantial lung collapse as they approach functional residual capacity, presumably due to the weight of the chest wall. It remains unclear why obese LONA asthmatics are hyperresponsive to methacholine while obese nonasthmatic individuals are not. Why only a subset of severely obese subjects develop late-onset nonallergic (LONA) asthma remains unknown, although it is widely assumed that compression of the lungs by the chest wall is somehow involved. We show that lung compression is common to obese individuals both without asthma and with LONA asthma but that those with LONA asthma may have increased airway wall compliance and possibly also a reduced ability to recruit collapsed lung.
Topics: Asthma; Bronchial Provocation Tests; Forced Expiratory Volume; Humans; Methacholine Chloride; Obesity
PubMed: 33119471
DOI: 10.1152/japplphysiol.00666.2020 -
The Cochrane Database of Systematic... Aug 2021Croup is an acute viral respiratory infection with upper airway mucosal inflammation that may cause respiratory distress. Most cases are mild. Moderate to severe croup... (Review)
Review
BACKGROUND
Croup is an acute viral respiratory infection with upper airway mucosal inflammation that may cause respiratory distress. Most cases are mild. Moderate to severe croup may require treatment with corticosteroids (the benefits of which are often delayed) and nebulised epinephrine (adrenaline) (the benefits of which may be short-lived and which can cause dose-related adverse effects including tachycardia, arrhythmias, and hypertension). Rarely, croup results in respiratory failure necessitating emergency intubation and ventilation. A mixture of helium and oxygen (heliox) may prevent morbidity and mortality in ventilated neonates by reducing the viscosity of the inhaled air. It is currently used during emergency transport of children with severe croup. Anecdotal evidence suggests that it relieves respiratory distress. This review updates versions published in 2010, 2013, and 2018.
OBJECTIVES
To examine the effect of heliox compared to oxygen or other active interventions, placebo, or no treatment on relieving signs and symptoms in children with croup as determined by a croup score and rates of admission and intubation.
SEARCH METHODS
We searched CENTRAL, which includes the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE, Embase, CINAHL, Web of Science, and LILACS, on 15 April 2021. We also searched the World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch/) and ClinicalTrials.gov (clinicaltrials.gov) on 15 April 2021. We contacted the British Oxygen Company, a leading supplier of heliox.
SELECTION CRITERIA
Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of heliox in comparison with placebo, no treatment, or any active intervention(s) in children with croup.
DATA COLLECTION AND ANALYSIS
We used standard methodological procedures expected by Cochrane. Data that could not be pooled for statistical analysis were reported descriptively.
MAIN RESULTS
We included 3 RCTs involving a total of 91 children aged between 6 months and 4 years. Study duration was from 7 to 16 months, and all studies were conducted in emergency departments. Two studies were conducted in the USA and one in Spain. Heliox was administered as a mixture of 70% heliox and 30% oxygen. Risk of bias was low in two studies and high in one study because of its open-label design. We did not identify any new trials for this 2021 update. One study of 15 children with mild croup compared heliox with 30% humidified oxygen administered for 20 minutes. There may be no difference in croup score changes between groups at 20 minutes (mean difference (MD) -0.83, 95% confidence interval (CI) -2.36 to 0.70) (Westley croup score, scale range 0 to 16). The mean croup score at 20 minutes postintervention may not differ between groups (MD -0.57, 95% CI -1.46 to 0.32). There may be no difference between groups in mean respiratory rate (MD 6.40, 95% CI -1.38 to 14.18) and mean heart rate (MD 14.50, 95% CI -8.49 to 37.49) at 20 minutes. The evidence for all outcomes in this comparison was of low certainty, downgraded for serious imprecision. All children were discharged, but information on hospitalisation, intubation, or re-presenting to emergency departments was not reported. In another study, 47 children with moderate croup received one dose of oral dexamethasone (0.3 mg/kg) with either heliox for 60 minutes or no treatment. Heliox may slightly improve Taussig croup scores (scale range 0 to 15) at 60 minutes postintervention (MD -1.10, 95% CI -1.96 to -0.24), but there may be no difference between groups at 120 minutes (MD -0.70, 95% CI -1.56 to 0.16). Children treated with heliox may have lower mean Taussig croup scores at 60 minutes (MD -1.11, 95% CI -2.05 to -0.17) but not at 120 minutes (MD -0.71, 95% CI -1.72 to 0.30). Children treated with heliox may have lower mean respiratory rates at 60 minutes (MD -4.94, 95% CI -9.66 to -0.22), but there may be no difference at 120 minutes (MD -3.17, 95% CI -7.83 to 1.49). There may be a difference in hospitalisation rates between groups (odds ratio 0.46, 95% CI 0.04 to 5.41). We assessed the evidence for all outcomes in this comparison as of low certainty, downgraded due to imprecision and high risk of bias related to an open-label design. Information on heart rate and intubation was not reported. In the third study, 29 children with moderate to severe croup all received continuous cool mist and intramuscular dexamethasone (0.6 mg/kg). They were then randomised to receive either heliox (given as a mixture of 70% helium and 30% oxygen) plus one to two doses of nebulised saline or 100% oxygen plus nebulised epinephrine (adrenaline), with gas therapy administered continuously for three hours. Heliox may slightly improve croup scores at 90 minutes postintervention, but may result in little or no difference overall using repeated-measures analysis. We assessed the evidence for all outcomes in this comparison as of low certainty, downgraded due to high risk of bias related to inadequate reporting. Information on hospitalisation or re-presenting to the emergency department was not reported. The included studies did not report on adverse events, intensive care admissions, or parental anxiety. We could not pool the available data because each comparison included data from only one study.
AUTHORS' CONCLUSIONS
Given the very limited available evidence, uncertainty remains regarding the effectiveness and safety of heliox. Heliox may not be more effective than 30% humidified oxygen for children with mild croup, but may be beneficial in the short term for children with moderate croup treated with dexamethasone. The effect of heliox may be similar to 100% oxygen given with one or two doses of adrenaline. Adverse events were not reported, and it is unclear if these were monitored in the included studies. Adequately powered RCTs comparing heliox with standard treatments are needed to further assess the role of heliox in the treatment of children with moderate to severe croup.
Topics: Airway Obstruction; Airway Resistance; Child; Child, Preschool; Croup; Helium; Humans; Infant; Oxygen; Oxygen Inhalation Therapy; Randomized Controlled Trials as Topic; Treatment Outcome
PubMed: 34397099
DOI: 10.1002/14651858.CD006822.pub6 -
ERJ Open Research Apr 2022The long-term effects of cannabis on small airway function remain unclear. We investigated associations between cannabis use and small airway function in a general...
BACKGROUND AND OBJECTIVE
The long-term effects of cannabis on small airway function remain unclear. We investigated associations between cannabis use and small airway function in a general population sample.
METHODS
Cannabis use was ascertained at multiple ages from age 18 to 45 years and quantified as joint-years among 895 participants in the Dunedin Multidisciplinary Health and Development Study. Small airway function at ages 38 and 45 years was measured using impulse oscillometry (IOS) before and after inhalation of salbutamol. Analyses used multiple linear regression adjusting for tobacco use, body mass index and height. Longitudinal analyses of cannabis use between 38 and 45 years also adjusted for IOS at age 38 years.
RESULTS
Associations between lifetime cannabis joint-years and IOS differed between men and women: in women, cannabis use was associated with pre-bronchodilator resistance at 5 Hz ( ) and 20 Hz ( ), reactance at 5 Hz, area of reactance and resonant frequency, and marginally associated with the difference between and . Cannabis use was only statistically significantly associated with pre-bronchodilator resonant frequency in men. Cannabis use between the ages of 38 and 45 years was associated with a similar pattern of changes in IOS measures. After salbutamol, cannabis use was only statistically significantly associated with and among women and none of the IOS measures among men.
CONCLUSIONS
Cannabis use is associated with small airway dysfunction at age 45 years, indicating an increase in peripheral airway resistance and reactance. These associations were greater and mostly only statistically significant among women. Associations were weaker and mostly nonsignificant after bronchodilator use, suggesting that cannabis-induced changes in small airways may be at least partially reversible.
PubMed: 35509440
DOI: 10.1183/23120541.00688-2021 -
Clinical and Experimental Dental... Feb 2021Functional problems, including nasal flow problems, are associated with specific skeletal and dental features. Further, maxillary expansion has been associated with...
OBJECTIVES
Functional problems, including nasal flow problems, are associated with specific skeletal and dental features. Further, maxillary expansion has been associated with nasal airway resistance alterations. This study aimed to investigate whether there is a correlation between skeletal features and nasal airflow- and olfaction-related problems.
MATERIALS AND METHODS
This prospective study included 68 patients (30 boys, 38 girls; mean age 9 ± 2 years) examined at the Ohu University Hospital. We classified patients into three skeletal Classes (Class I, II, and III) based on the ANB angle. Olfactory disorder history was collected from the guardians. Maxillofacial measurements, nasal airflow assessments, and olfactory tests were performed using cephalometric analysis, rhinomanometry, and T&T olfactometer, respectively.
RESULTS
Malocclusion, resulting from skeletal mandibular protrusion and smaller maxilla, was associated with reduced olfaction in children. The detection and recognition thresholds of skeletal Class III were significantly higher than those of Classes I (p = .01) and II (p = .01). Significant correlations were observed between SNA and the detection threshold (r = -.50) as well as between nasion perpendicular-point A and the recognition threshold (r = -.53). The detection and recognition thresholds were significantly higher in Class III than in Classes I (r = .3) and II (r = -.1).
CONCLUSIONS
Maxillary growth and development may be associated with olfaction in children. Changing the maxillofacial morphology may improve olfactory function. In the future, we will investigate how malocclusion treatment affects olfactory function.
Topics: Cephalometry; Child; Female; Humans; Male; Malocclusion; Maxilla; Prospective Studies; Smell
PubMed: 32977366
DOI: 10.1002/cre2.329 -
American Journal of Respiratory and... Feb 2024Respiratory resistance (Rrs) and reactance (Xrs) as measured by oscillometry and their intrabreath changes have emerged as sensitive parameters for detecting early...
Respiratory resistance (Rrs) and reactance (Xrs) as measured by oscillometry and their intrabreath changes have emerged as sensitive parameters for detecting early pathological impairments during tidal breathing. This study evaluates the prevalence and association of abnormal oscillometry parameters with respiratory symptoms and respiratory diseases in a general adult population. A total of 7,560 subjects in the Austrian LEAD (Lung, hEart, sociAl, boDy) Study with oscillometry measurements (computed with the Resmon Pro FULL; Restech Srl) were included in this study. The presence of respiratory symptoms and doctor-diagnosed respiratory diseases was assessed using an interview-based questionnaire. Rrs and Xrs at 5 Hz, their inspiratory and expiratory components, the area above the Xrs curve, and the presence of tidal expiratory flow limitation were analyzed. Normality ranges for oscillometry parameters were defined. The overall prevalence of abnormal oscillometry parameters was 20%. The incidence of abnormal oscillometry increased in the presence of symptoms or diagnoses: 17% (16-18%) versus 27% (25-29%), < 0.0001. All abnormal oscillometry parameters except Rrs at 5 Hz were significantly associated with respiratory symptoms/diseases. Significant associations were found, even in subjects with normal spirometry, with abnormal oscillometry incidence rates increasing by 6% (4-8%; < 0.0001) in subjects with symptoms or diagnoses. Abnormal oscillometry parameters are present in one-fifth of this adult population and are significantly associated with respiratory symptoms and disease. Our findings underscore the potential of oscillometry as a tool for detecting and evaluating respiratory impairments, even in individuals with normal spirometry.
Topics: Adult; Humans; Oscillometry; Lung; Respiration; Exhalation; Respiratory Tract Diseases; Spirometry; Forced Expiratory Volume; Airway Resistance
PubMed: 37972230
DOI: 10.1164/rccm.202306-0975OC