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Diagnostics (Basel, Switzerland) May 2024The fact that some SARS-CoV-2 pneumonia patients benefit from changing body position, and some from continuous positive airways pressure (CPAP), indicates the functional...
The fact that some SARS-CoV-2 pneumonia patients benefit from changing body position, and some from continuous positive airways pressure (CPAP), indicates the functional character of hypoxia. We hypothesize that such effects could be explained by the closure of small airways. To prove the hypothesis, we evaluated the patency of small airways in 30 oxygen-dependent, spontaneously breathing patients with SARS-CoV-2 pneumonia during their hospital stay using the FOT method and then compared the results with data obtained three months later. During the acute period, total resistance (R5) and peripheral resistance (R5-20) rose above the upper limit of normal (ULN) in 28% and 50% of all patients, respectively. Reactance indices X5, AX and Fres exceeded ULN in 55%, 68% and 66% of cases. Significant correlations were observed between PaO/FiO, the time spent in the hospital and R5, X5, AX and Fres. After 3 months, 18 patients were re-examined. During the hospital stay, 11 of them had risen above the upper limit of normal (ULN), for both resistance (R5-20) and reactance (X5, AX) values. Three months later, ULN for R5-20 was exceeded in only four individuals, but ULN for X5 and AX was exceeded in five individuals. Lung function examination revealed a combined restrictive/obstructive ventilatory failure and reduced CO transfer factor. We interpret these changes as lung tissue remodeling due to the process of fibrosis. We conclude that during acute period of SARS-CoV-2 pneumonia, dilated pulmonary blood vessels and parenchymal oedema induce functional closure of small airways, which in turn induce atelectasis with pulmonary right-to-left shunting, followed by the resulting hypoxemia.
PubMed: 38893686
DOI: 10.3390/diagnostics14111160 -
The Journal of the Association of... May 2024Spirometry is used extensively, but airway oscillometry is gaining acceptance for evaluating obstructive airway disorders. Moderate persistent asthma requires daily... (Comparative Study)
Comparative Study
BACKGROUND
Spirometry is used extensively, but airway oscillometry is gaining acceptance for evaluating obstructive airway disorders. Moderate persistent asthma requires daily treatment with inhaled corticosteroids (ICS).
MATERIALS AND METHODS
We aimed to examine the relationship between airway oscillometry and lung volumes, which are the markers of lung physiology in obstructive airway disease and spirometry in the real-world clinical setting. A total of 72 adults with moderate persistent asthma followed up in our outpatient department from November 2021 to August 2022, and their clinical details and tests of spirometry, forced oscillation technique (FOT), and lung volumes by body plethysmography (BP) performed before and after bronchodilator administration were analyzed.
RESULTS
The mean age of the study population was 40 years, and the majority (57%) were females. FOT detected airflow limitation in 12 of the 31 patients with normal spirometry. BP detected abnormalities in more patients than both spirometry and FOT (91.6 vs 73.6%, < 0.001). Respiratory resistance 5 (R5) had a negative correlation with functional residual capacity (FRC) and total lung capacity (TLC). Reactance 5 (X5) correlated positively with inspiratory capacity (IC) and TLC and negatively with reserve volume (RV)/TLC ratio. A positive correlation was found between IC/TLC% and postbronchodilator X5 and between R5 and 19 and RV/TLC. R5 had a negative and X5 had a positive correlation with forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC, and maximal mid expiratory flow rates (MMEF). ∇X5 had a negative correlation with FEV1, MMEF, and FEV1/FVC. Spirometry detected postbronchodilator responsiveness in more patients than FOT when only the R5 criterion was used and in a comparable number when the X5 criterion was added. ∇X5 and R5-R19/R5 declined significantly after bronchodilators.
CONCLUSION
We concluded that there is a moderate correlation between FOT and spirometry and lung volumes by BP. FOT and spirometry should be used together to identify airflow obstruction and postbronchodilator responsiveness in asthma. Lung volumes by BP identify more abnormalities in adults with asthma than both spirometry and FOT. Thresholds to define postbronchodilator responsiveness (PBDR) for ∇X5 and R5-R19 need to be defined.
Topics: Humans; Asthma; Female; Adult; Male; Spirometry; Middle Aged; Plethysmography, Whole Body; Oscillometry; Bronchodilator Agents; Lung Volume Measurements; Lung
PubMed: 38881107
DOI: 10.59556/japi.72.0520 -
Clinical Physiology and Functional... Jun 2024Expiratory flow limitation (EFL) during tidal breathing and lung hyperinflation have been identified as major decisive factors for disease status, prognosis and...
BACKGROUND
Expiratory flow limitation (EFL) during tidal breathing and lung hyperinflation have been identified as major decisive factors for disease status, prognosis and response to therapy in obstructive lung diseases.
AIM
To investigate the delta values between expiratory and inspiratory resistance and reactance, measured using respiratory oscillometry and its correlation with air trapping and symptoms in subjects with obstructive lung diseases.
METHODS
Four hundred and seventy-one subjects (96 with chronic obstructive pulmonary disease [COPD], 311 with asthma, 30 healthy smokers and 34 healthy subjects) were included. Spirometry, body plethysmography and respiratory oscillometry measurements were performed and the differences between the expiratory and inspiratory respiratory oscillometry values (as delta values) were calculated. Questionnaires regarding symptoms and quality of life were administered.
RESULTS
Patients with COPD and healthy smokers had an increased delta resistance at 5 Hz (R5) compared with patients with asthma (p < 0.0001 and p = 0.037, respectively) and healthy subjects (p = 0.0004 and p = 0.012, respectively). Patients with COPD also had higher values of ΔR5-R19 than healthy subjects (p = 0.0001) and patients with asthma (p < 0.0001). Delta reactance at 5 Hz (X5) was significantly more impaired in COPD patients than in asthma and healthy subjects (p < 0.0001 for all). There was a correlation between the ratio of residual volume and total lung capacity and ΔR5 (p = 0.0047; r = 0.32), ΔR5-R19 (p = 0.0002; r = 0.41) and ΔX5 (p < 0.0001; r = -0.44), for all subjects. ΔX5 correlated with symptoms in COPD, healthy smokers and patients with asthma. In addition, ΔR5 correlated with asthma symptoms.
CONCLUSION
EFL was most prominent in parameters measuring peripheral resistance and reactance and correlated with air trapping and airway symptoms.
PubMed: 38873744
DOI: 10.1111/cpf.12895 -
Respiration; International Review of... Jun 2024within-breath analysis of oscillometry parameters is a growing research area since it increases sensitivity and specificity to respiratory pathologies and conditions....
BACKGROUND
within-breath analysis of oscillometry parameters is a growing research area since it increases sensitivity and specificity to respiratory pathologies and conditions. However, reference equations for these parameters in White adults are lacking and devices using multiple sinusoids or pseudorandom forcing stimuli have been underrepresented in previous studies deriving reference equations. The current study aims to establish reference ranges for oscillometry parameters, including also the within-breath ones in White adults using multi-sinusoidal oscillations.
METHODS
White adults with normal spirometry, BMI≤30kg/m2, without a smoking history, respiratory symptoms, pulmonary or cardiac disease, neurological or neuromuscular disorders, and respiratory tract infections in the previous 4 weeks were eligible for the study. Study subjects underwent oscillometry (multifrequency waveform at 5-11-19Hz, Resmon PRO FULL, Restech Srl, Italy) in 5 centers in Europe and the USA according to international standards. The within-breath and total resistance (R) and reactance (X), the resonance frequency, the area under the X curve, the frequency dependence of R (R5-19), and within-breath changes of X (ΔX) were submitted to Lambda-Mu-Sigma models for deriving reference equations. For each output parameter, an AIC-based stepwise input variable selection procedure was applied.
RESULTS
144 subjects (age 20.8 - 86.3 years; height 146 - 193 cm; BMI 17.42 - 29.98 kg/m2; 56% females) were included. We derived reference equations for 29 oscillatory parameters. Predicted values for inspiratory and expiratory parameters were similar, while differences were observed for their limits of normality.
CONCLUSIONS
We derived reference equations with narrow confidence intervals for within-breath and whole-breath oscillatory parameters for White adults.
PubMed: 38843786
DOI: 10.1159/000539532 -
The Journal of Allergy and Clinical... Aug 2024The combination of an inhaled corticosteroid (ICS) and long-acting β-agonist (LABA) (ICS/LABA) has shown superiority in improving lung function (FEV) compared with an...
BACKGROUND
The combination of an inhaled corticosteroid (ICS) and long-acting β-agonist (LABA) (ICS/LABA) has shown superiority in improving lung function (FEV) compared with an ICS alone. The clinical effect of a ICS/LABA combination depends on the fine-particle fraction and the pulmonary deposition.
OBJECTIVE
We sought to compare the efficacy of 2 combinations of an ICS and LABA, namely, fluticasone propionate (FP) and formoterol (FORM) (FP/FORM) and fluticasone furoate (FF) and vilanterol (VI) (FF/VI), in asthmatic adolescents with chronic bronchial obstruction.
METHODS
FP/FORM (125 μg/5 μg, 2 doses twice daily via the k-haler [Mundipharma, Cambridge, UK]) and FF/VI (92 μg/22 μg, once daily via the Ellipta inhaler [GlaxoSmithKline]) were administered to adolescents aged 12 to 17 years who required regular antiasthmatic medication and had a ratio of FEV to forced vital capacity (FEV/FVC) less than -1.65 SD in a 2-sequence, 16-week crossover trial. The primary efficacy end point was change in FEV compared with baseline. Secondary end points were FEV/FVC ratio, maximal expiratory flow at 50% of the FVC, impulse oscillometry indices respiratory resistance at 5 Hz (R5), difference between R5 and respiratory resistance at 20 Hz (R20), area of reactance, and Asthma Control Test score.
RESULTS
Both ICS/LABA combinations resulted in a significant improvement in FEV and maximal expiratory flow at 50% of the FVC scores without any significant difference between FP/FORM and FF/VI, with 40% of patients with either treatment achieving a normal prebronchodilator FEV/FVC score. Neither area of reactance nor difference between R5 and R20 improved significantly with either treatment.
CONCLUSION
Both ICS/LABA combinations demonstrated significant improvements in FEV score. More than one-third of the asthmatic adolescents with prolonged bronchial obstruction achieved a normal prebronchodilator FEV/FVC ratio.
PubMed: 38826625
DOI: 10.1016/j.jacig.2024.100268 -
Pediatric Pulmonology May 2024This study compares home-based oscillometry and spirometry for characterizing respiratory system disease in school-aged children with bronchopulmonary dysplasia (BPD) in...
INTRODUCTION
This study compares home-based oscillometry and spirometry for characterizing respiratory system disease in school-aged children with bronchopulmonary dysplasia (BPD) in clinical research. We hypothesized higher rates of successful completion and abnormal cases identified through oscillometry, with correlations between device measurements.
METHODS
Participants 6-12 years old with BPD in the ongoing Air Quality, Environment and Respiratory Outcomes in BPD (AERO-BPD) study performed oscillometry followed by spirometry at two separate home visits. Parameters measured included airway resistance at 5 Hz(R), resistance from 5 to 19 Hz(R), resonance frequency(F), reactance at 5 Hz(X), area under the curve between F and X(AX), forced expiratory volume in 1 second(FEV), forced vital capacity(FVC), and FEV/FVC. Descriptive statistics identified the proportion of successful tests, correlation in measurements, and rate of lung disease for each device.
RESULTS
Among 76 subjects with 120 paired observations, 95% and 71% of participants successfully performed oscillometry and spirometry, respectively, at home visit one. 98% and 77% successfully performed oscillometry and spirometry, respectively, at home visit two. Odds ratios favored oscillometry (range 5.31-10.13, p < 0.01). FEV correlated with AX (correlation coefficient r = -0.27, p = 0.03); FEV/FVC with AX (r = -0.32, p = 0.02); and FEV/FVC with R (r = -0.37, p = 0.01). AX exhibited the highest prevalence of abnormality at 25%; other oscillometry parameters ranged from 5%-22%. Forty-five to sixty-four percent of participants had abnormal spirometry. Oscillometry assessments had significantly lower odds of capturing lung disease (odds ratios 0.07-0.24, p < 0.0001).
CONCLUSIONS
School-aged children with BPD demonstrated higher success rates in field-based oscillometry than spirometry. Spirometry exhibited higher rates of abnormality than oscillometry. Moderate correlation exists between device measurements.
PubMed: 38804690
DOI: 10.1002/ppul.27072 -
Journal of Clinical Medicine May 2024High-resolution computed tomography (HRCT) may lack sensitivity for the early detection of interstitial lung disease associated with systemic sclerosis (SSc-ILD). Lung...
High-resolution computed tomography (HRCT) may lack sensitivity for the early detection of interstitial lung disease associated with systemic sclerosis (SSc-ILD). Lung ultrasound is an emerging technique for the diagnosis of SSc-ILD. This cross-sectional study aimed to describe the prevalence of ultrasound interstitial syndrome in SSc patients with normal HRCT and pulmonary function tests (PFT). Thirty SSc patients with normal HRCT, FVC > 80% predicted and DLCO > 70% predicted were included. Echocardiography and PFT including impulse oscillometry and cardiopulmonary exercise testing were performed. Lung ultrasound was analyzed by two blinded operators. Patients were classified into two groups, according to the presence or absence of ultrasound interstitial syndrome, defined as the sum of B-lines in all thoracic areas ≥10 and/or pleural line thickness >3 mm on at least one thoracic area and/or a pleural line irregularity score >16%. Ultrasound interstitial syndrome was present in 12 patients (40%). Inter-reader agreement for the diagnosis of ultrasound interstitial syndrome defined by the Kappa coefficient was 0.93 (95%CI 0.79-1.00). Patients with ultrasound interstitial syndrome were younger (37 years vs. 53 years, = 0.009), more often had pitting scars ( = 7/12 vs. 3/18, = 0.045) and had lower FVC (102 vs. 110% pred, = 0.009), TLC (114 vs. 122% pred, = 0.042) and low-frequency respiratory system reactance (Xrs5 Z-score 0.16 vs. 1.02, = 0.018), while pulmonary gas exchange was similar. Ultrasound interstitial syndrome was detected in 12/30 SSc patients with normal HRCT and PFT. Patients with ultrasound interstitial syndrome had differences in lung function consistent with reduced respiratory compliance, suggesting minimal and/or early suspected SSc-ILD.
PubMed: 38792426
DOI: 10.3390/jcm13102885 -
Tuberculosis and Respiratory Diseases Apr 2024: Bronchiectasis is a chronic respiratory disease that leads to airway inflammation, destruction, and airflow limitation, which reflects its severity. Impulse...
BACKGROUND
: Bronchiectasis is a chronic respiratory disease that leads to airway inflammation, destruction, and airflow limitation, which reflects its severity. Impulse oscillometry (IOS) is a non-invasive method that uses sound waves to estimate lung function and airway resistance. The aim of this study was to assess the usefulness of IOS in predicting the severity of bronchiectasis.
METHODS
: We retrospectively reviewed the IOS parameters and clinical characteristics in 145 patients diagnosed with bronchiectasis between March 2020 and May 2021. Disease severity was evaluated using the FACED score, and patients were divided into mild and moderate/severe groups.
RESULTS
: Forty-four patients (30.3%) were in the moderate/severe group, and 101 (69.7%) were in the mild group. Patients with moderate/severe bronchiectasis had a higher airway resistance at 5 Hz (R5), a higher difference between the resistance at 5 and 20 Hz (R5-R20), a higher resonant frequency (Fres), and a higher area of reactance (AX) than patients with mild bronchiectasis. R5 ≥0.43, resistance at 20 Hz (R20) ≥0.234, R5-R20 ≥28.3, AX ≥1.02, reactance at 5 Hz (X5) ≤-0.238, and Fres ≥20.88 revealed significant univariable relationships with bronchiectasis severity (p<0.05). Among these, only X5 ≤-0.238 exhibited a significant multivariable relationship with bronchiectasis severity (p=0.039). The receiver operating characteristic curve for predicting moderate- to-severe bronchiectasis of FACED score based on IOS parameters exhibited an area under the curve of 0.809.
CONCLUSION
: The IOS assessed by the disease severity of FACED score can effectively reflect airway resistance and elasticity in bronchiectasis patients and serve as valuable tools for predicting bronchiectasis severity.
PubMed: 38783483
DOI: 10.4046/trd.2023.0160 -
American Journal of Physiology. Lung... May 2024This study investigated the relationship between three respiratory support approaches on lung volume recruitment during the first two hours of postnatal life in preterm...
This study investigated the relationship between three respiratory support approaches on lung volume recruitment during the first two hours of postnatal life in preterm lambs. We estimated changes in lung aeration, measuring respiratory resistance and reactance by oscillometry at 5 Hz. We also measured intratracheal pressure in subsets of lambs. The first main finding is that sustained inflation (SI) applied noninvasively (Mask SI; n=7) or invasively (endotracheal tube, ETT SI; n=6) led to similar rapid lung volume recruitment (~6 min). In contrast, Mask continuous positive airway pressure (CPAP) without SI (n=6) resuscitation took longer (~30-45 min) to reach similar lung volume recruitment. The second main finding is that, in the first 15 min of postnatal life, the Mask CPAP without SI group closed their larynx during custom ventilator-driven expiration, leading to intratracheal positive end-expiratory pressure of ~17 cmHO (instead of 8 cmHO provided by the ventilator). In contrast, the Mask SI group used the larynx to limit inspiratory pressure to ~26 cmHO (instead of 30 cmHO provided by the ventilator). These different responses affected tidal volume, being larger in the Mask CPAP without SI group (8.4 ml/Kg, 6.7-9.3 IQR) compared to the Mask SI (5.0 ml/Kg, 4.4-5.2 IQR), and ETT SI groups (3.3 ml/Kg 2.6-3.7 IQR). Distinct physiological responses suggest that spontaneous respiratory activity of the larynx of preterm lambs at birth can uncouple pressure applied by the ventilator to that applied to the lung, leading to unpredictable lung pressure and tidal volumes delivery independently from the ventilator settings.
PubMed: 38771135
DOI: 10.1152/ajplung.00236.2022 -
European Journal of Anaesthesiology Jul 2024Atelectasis has been reported in 68 to 100% of children undergoing general anaesthesia, a phenomenon that persists into the recovery period. Children receiving... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Atelectasis has been reported in 68 to 100% of children undergoing general anaesthesia, a phenomenon that persists into the recovery period. Children receiving recruitment manoeuvres have less atelectasis and fewer episodes of oxygen desaturation during emergence. The optimal type of recruitment manoeuvre is unclear and may be influenced by the airway device chosen.
OBJECTIVE
We aimed to investigate the different effects on lung mechanics as assessed by the forced oscillation technique (FOT) utilising different recruitment strategies: repeated inflations vs. one sustained inflation and different airway devices, a supraglottic airway device vs. a cuffed tracheal tube.
DESIGN
Pragmatic enrolment with randomisation to the recruitment strategy.
SETTING
We conducted this single-centre trial between February 2020 and March 2022.
PARTICIPANTS
Seventy healthy patients (53 boys) aged between 2 and 16 years undergoing general anaesthesia were included.
INTERVENTIONS
Forced oscillations (5 Hz) were superimposed on the ventilator waveform using a customised system connected to the anaesthesia machine. Pressure and flow were measured at the inlet of the airway device and used to compute respiratory system resistance and reactance. Measurements were taken before and after recruitment, and again at the end of surgery.
MAIN OUTCOME MEASURES
The primary endpoint measured is the change in respiratory reactance.
RESULTS
Statistical analysis (linear model with recruitment strategy and airway device as factors) did not show any significant difference in resistance and reactance between before and after recruitment. Baseline reactance was the strongest predictor for a change in reactance after recruitment: prerecruitment Xrs decreased by mean (standard error) of 0.25 (0.068) cmH 2 O s l -1 per 1 cmH 2 O -1 s l -1 increase in baseline Xrs ( P < 0.001). After correcting for baseline reactance, the change in reactance after recruitment was significantly lower for sustained inflation compared with repeated inflation by mean (standard error) 0.25 (0.101) cmH 2 O ( P = 0.0166).
CONCLUSION
Although there was no significant difference between airway devices, this study demonstrated more effective recruitment via repeated inflations than sustained inflation in anaesthetised children.
TRIAL REGISTRATION
Australian New Zealand Clinical Trials Registry: ACTRN12619001434189.
Topics: Humans; Anesthesia, General; Child; Male; Female; Adolescent; Child, Preschool; Respiratory Mechanics; Intubation, Intratracheal; Airway Management; Lung; Pulmonary Atelectasis; Respiration, Artificial
PubMed: 38769936
DOI: 10.1097/EJA.0000000000001999