Zoltan Hantos

• PhD, DSc
• Professor Emeritus at University of Szeged

Background Infant pulmonary function testing (iPFT) in low‐ and middle‐income countries is limited. We evaluated the early feasibility of iPFT in rural Bangladesh. Methods Experts established an iPFT laboratory at Zakiganj Upazila Health Complex in Sylhet, Bangladesh and trained staff. Infants ≤ 6 months old participating in a cohort study between...

Background Preterm birth is associated with increased mortality and morbidity, particularly due to lung disease. Low-middle income countries (LMIC) have the highest rates of preterm birth. Infants born extremely preterm rarely survive, so the largest burden is amongst moderate to late preterm (MLP) infants. The long-term health impact on MLP childr...

Background: Fibrodysplasia ossificans progressiva (FOP) is an ultra-rare genetic bone disease that is characterized by progressive heterotopic ossification of the thoracic cavity. Prognosis is poor with cardiopulmonary complications being the main cause of death. Spirometry is a well-established metric of functional exercise capacity and prognosis...

Intra-breath oscillometry potentially offers detailed information regarding airway function, with increasing magnitude of difference between resistance and reactance at end-expiration to end-inspiration potentially associated with obstructive airway disease, but less is known about specific respiratory mechanics in preterm-born children using this...

Background: Assessing respiratory mechanics in patients with acute hypoxemic respiratory failure who are not intubated could provide useful information about illness trajectory. Oscillometry is a respiratory function test used to measure total respiratory impedance during tidal breathing, which reveals resistive and elastic properties of the lung....

Background Longitudinal measurements of intrabreath respiratory impedance (Zrs) in preschool‐aged children may be able to distinguish abnormal lung function trajectories in children with a history of wheezing compared to healthy ones. Methods Children from a prospective, longitudinal community‐based cohort performed annual intrabreath oscillometry...

Background Early life is a key period that determines long-term health. Lung development in childhood predicts lung function attained in adulthood and morbidity and mortality across the life course. We aimed to assess the effect of early-life lower respiratory tract infection (LRTI) and associated risk factors on lung development from birth to scho...

Oscillometry is an emerging pulmonary function testing tool that is conducted during tidal breaths with minimal patient effort. It is highly sensitive to changes in lung mechanics. Oscillometry was recently shown to be highly associated with disease severity in idiopathic pulmonary fibrosis (IPF). The usefulness of oscillometry after single lung tr...

Background Intra-breath oscillometry has been proposed as a sensitive means of detecting airway obstruction in young children. We aimed to assess the impact of early life wheezing and lower respiratory tract illness on lung function, using both standard and intra-breath oscillometry in 3 year old children. Methods History of doctor-diagnosed asthm...

Background Continuous positive airway pressure (CPAP) therapy has profound effects in obesity hypoventilation syndrome (OHS). Current therapy initiation focuses on upper airway patency rather than the assessment of altered respiratory mechanics due to increased extrapulmonary mechanical load. Methods We aimed to examine the viability of intra-brea...

Background Longitudinal measurements of intra-breath respiratory impedance (Zrs) in preschool-aged children may be able to distinguish abnormal lung function trajectories in children with a history of wheezing compared to healthy ones. Methods Children from a prospective, longitudinal community-based cohort performed annual intra-breath oscillometr...

Background: Ventilation inhomogeneity (VI) is measured in patients with Cystic Fibrosis (CF) by lung clearance index (LCI) using the Multiple Breath Washout (MBW). In young children, feasibility is often low within busy clinical settings. Intra-breath oscillometry (IB-OSC) measures respiratory system reactance (Xrs), which is determined by the same...

Introduction Mechanisms underlying lung dysfunction after preterm birth are poorly understood. Studying phenotypes of prematurity‐associated lung disease may aid understanding of underlying mechanisms. Preterm‐born children with and without lung dysfunction and term controls were assessed using oscillometry before and after exercise, and after post...

Background and objective: Indoor air pollution (IAP) and tobacco smoke exposure (ETS) are global health concerns contributing to the burden of childhood respiratory disease. Studies assessing the effects of IAP and ETS in preschool children are limited. We assessed the impact of antenatal and postnatal IAP and ETS exposure on lung function in a So...

Background Respiratory syncytial virus (RSV) is the most common cause of hospitalisation for lower respiratory tract infection (LRTI) in children. RSV LRTI during early childhood may increase susceptibility to recurrent wheezing and asthma. Research question The aim of this study was to describe the pulmonary sequelae at 1 and 2 years of age follo...

The growing increase in the use of oscillometry as an important adjunct to or a potential substitute for conventional pulmonary function tests (PFTs) has urged the standardisation of this technique, which was established for forced spirometry in 2005 [1] and updated in 2019 [2]. A key component of the standardisation of the PFTs is the establishmen...

Introduction Non-invasive measurement of respiratory impedance by oscillometry can be used in young children from 3 years and those unable to perform forced respiratory manoeuvres. It can discriminate between healthy children and those with respiratory disease. However, its clinical application is limited by the lack of reference data for African p...

Background: Chronic lung allograft dysfunction (CLAD) is the major cause of death beyond 2 years after lung transplantation and develops in 50% of all patients by 5 years post-transplant. CLAD is diagnosed on the basis of a sustained drop of 20% for at least 3 months in the forced expiratory volume (FEV1), compared to the best baseline value achiev...

Pulmonary diseases represent four out of ten most common causes for worldwide mortality. Thus, pulmonary infections with subsequent inflammatory responses represent a major public health concern. The pulmonary barrier is a vulnerable entry site for several stress factors, including pathogens such as viruses, and bacteria, but also environmental fac...

Background Altered respiratory mechanics due to increased extrapulmonary mechanical load may be the key to understanding the profound effect of continuous positive airway pressure (CPAP) therapy in obesity hypoventilation syndrome (OHS). Methods We performed a cross-sectional study to assess intra-breath mechanical changes in an OHS population. 10...

Background Markers of idiopathic pulmonary fibrosis (IPF) severity are based on measurements of forced vital capacity (FVC), diffusing capacity (DLCO) and CT. The pulmonary vessel volume (PVV) is a novel quantitative and independent prognostic structural indicator derived from automated CT analysis. The current prospective cross-sectional study inv...

Background Oscillometry has been employed widely as a non-invasive and standardized measurement of respiratory function in children and adults; however, limited information is available on infants. Aims To establish the within-session variability of respiratory impedance (Zrs), to characterize the degree and profile of intra-breath changes in Zrs...

Objective: Recent studies in respiratory system impedance (Zrs) with single-frequency oscillometry have demonstrated the utility of novel intra-breath measures of Zrs in the detection of pathological alterations in respiratory mechanics. In the present work, we addressed the feasibility of extracting intra-breath information from Zrs data sets obt...

Background Asthma control is not well reflected by spirometry, yet this is the most frequently used measure of lung function in asthma clinics. Oscillometry is an alternative technique suitable for those with severe asthma. Objective We aimed to investigate usefulness of oscillometry in subjects with severe asthma to determine which outcome variab...

Respiratory oscillometry (also known as the forced oscillation technique) is increasingly contributing to lung function studies in clinical routine and research, as a result of its sophistication, non-invasiveness and minimal interaction with normal breathing. Oscillometry has focused traditionally on the frequency dependence of respiratory impedan...

Oscillometric measurements of respiratory system resistance (R rs ) in infants are usually made via the nasal pathways, which not only significantly contribute to overall R rs , but also introduce marked flow (V')-dependent changes. We employed intrabreath oscillometry in casts of the upper airways constructed from head CT images of 46 infants. We...

Background: The guidelines to conduct and interpret conventional pulmonary function (PFT) tests are frequently reviewed and updated. However, the quality assurance and quality control (QA/QC) guidelines for respiratory oscillometry testing remain limited. QA/QC guidelines are essential for oscillometry to be used as a diagnostic pulmonary function...

Noninvasiveness, low cooperation demand and the potential for detailed physiological characterisation have promoted the use of oscillometry in the assessment of lung function. However, concerns have been raised about the comparability of measurement outcomes delivered by the different oscillometry devices. The present study compares the performance...

Rationale: Lower respiratory tract illness (LRTI) is a leading cause of mortality and morbidity in children. Sensitive and non-invasive infant lung function techniques are needed to measure risk for and impact of LRTI on lung health. Objective: To investigate whether lung function derived from the intra-breath forced oscillation technique (FOT),...

The forced oscillations technique (FOT) enables a non-invasive monitoring of respiratory mechanics, returning the impedance of the respiratory system (Z rs ) at chosen frequencies. Recently it has been shown that the intrabreath variations of Z rs are correlated with respiratory diseases, mainly due to the sensitivity of Z rs to morphological chang...

Background and objective: Selecting 'healthy' preschool-aged children for reference ranges may not be straightforward. Relaxing inclusion criteria for normative data does not affect spirometry z-scores. We therefore investigated the effect of similarly relaxing inclusion criteria in preschoolers on reference ranges for respiratory impedance (Zrs)...

Tracking of the within-breath changes of respiratory mechanics using the forced oscillation technique may provide outcomes that characterise the dynamic behaviour of the airways during normal breathing. We measured respiratory resistance ( R rs ) and reactance ( X rs ) at 8 Hz in 55 chronic obstructive pulmonary disease (COPD) patients and 20 healt...

Background: Low lung function in early life is associated with later respiratory illness. There is limited data on lung function in African infants despite a high prevalence of respiratory disease. Aim: To assess the determinants of early lung function in African infants. Method: Infants enrolled in a South African birth cohort, the Drakenstei...

Background and objective: Mannitol challenge testing is an established tool for clinical asthma diagnosis, and can be performed outside of specialized respiratory laboratories. Despite applicability in both clinical and non-clinical populations, with different pre-test asthma probabilities, differences in diagnostic properties have not been well e...

Introduction: Perioperative respiratory complications (PRAE) are the most common complications during paediatric surgery. Obesity impairs respiratory mechanics and is a significant risk factor for PRAE. We hypothesised a change in respiratory mechanics between seated and supine position will be significantly different in obese children compared wit...

Intro: Perioperative respiratory complications (PRAE) are the most common complications encountered during paediatric surgery. Specific active respiratory symptoms identified as risk factors are associated with increased incidence of PRAE. The impact of altered respiratory mechanics on the risk for PRAE is poorly understood. We hypothesised that wo...

Rationale Individual assessment of airway obstruction in preschool-age children requires sensitive and specific lung function methods with low demand of cooperation. Although the forced oscillation technique (FOT) is feasible in young children, conventional measurements of respiratory impedance (Zrs) have limited diagnostic power in individuals. Ob...

Ready access to physiologic measures, including respiratory mechanics, lung volumes, and ventilation/perfusion inhomogeneity, could optimize the clinical management of the critically ill pediatric or neonatal patient and minimize lung injury. There are many techniques for measuring respiratory function in infants and children but very limited infor...

Background: Even though laryngeal mask airways (LMAs) are the most commonly used airway in paediatric anaesthesia, little is known about the assessment of respiratory mechanics in this setting. Methods: We measured respiratory resistance (R) and reactance (X) with forced oscillations at 16 Hz superimposed on spontaneous breathing following inductio...

Introduction: Positive response to mannitol has been suggested as a specific measure of asthma. Despite the high specificity, the challenge test can only identify a small proportion of asthmatic patients. Methods: Tidal changes in respiratory mechanics were measured with forced oscillations at 8 Hz in asthmatics [15 responders (PR) and 20 non-respo...

The diagnostic value of FEV1 for assessing functional impairment in asthma has been debated, primarily because forced expiratory manoeuvres may alter bronchial tone. The forced oscillation technique (FOT) does not affect the baseline tone, thus may be a more appropriate tool to evaluate the bronchodilator response (BDR) in children. FOT and spirom...

Monitoring within-breath changes in respiratory mechanics during the first days of life can reveal new aspects of perinatal adaptation. Our preliminary measurements exhibit a significant dependence of the mechanical impedance (Zrs) on tidal flow (V'), with different patterns of interdependence between resistance (R) and reactance (X). Healthy term...

Population-appropriate lung function reference data are essential to accurately identify respiratory disease and measure response to interventions. There are currently no reference data in African infants. The aim was to describe normal lung function in healthy African infants. Lung function was performed on healthy South African infants enrolled i...

Appendix S1 Statistical analysis. Table S1 Demographics and socioeconomic characteristics of participants by study site. Table S2 Univariate and multivariate analysis for tidal volume. Table S3 Univariate and multivariate analysis for respiratory rate. Table S4 Univariate and multivariate analysis for minute ventilation. Table S5 Univariate and mul...

Structural and functional longitudinal alterations of the lungs were followed in an emphysema model. Rats were treated with porcine pancreatic elastase (PPE, n=21) or saline (controls, C, n=19). Before the treatment and 3, 10, 21 and 105 days thereafter, absolute lung volumes (FRC, TLC and RV) and tissue mechanical parameters (elastance: H; damping...

Background and objectiveNon-invasive techniques for measuring lung mechanics in infants are needed for a better understanding of lung growth and function, and to study the effects of prenatal factors on subsequent lung growth in healthy infants. The forced oscillation technique requires minimal cooperation from the individual but has rarely been us...

Background Lung function data in healthy newborn infants are scarce largely due to lack of suitable techniques, although data for developmental and prenatal exposure studies are much needed. We have modified the forced oscillation technique (FOT) for the measurement of respiratory mechanical impedance (Zrs) in unsedated sleeping infants in the firs...

The present invention provides a method of measuring an acoustic impedance of a respiratory system. The method comprises selecting a frequency range for an acoustic wave, directing the acoustic wave into the respiratory system and receiving an acoustic wave from the respiratory system. The method also comprises determining the acoustic impedance fo...

The impact of mechanical ventilation with high VT-low PEEP in infant rats with preinjured lungs is unknown. After tracheal instillation of saline or acid, two week old rats were ventilated with VT 7mL/kg and PEEP 5 cmH2O or VT 21mL/kg and PEEP 1 cmH2O for 4h. Airway resistance and the coefficient of tissue elastance, measured via low-frequency forc...

Because of the minimal demand for cooperation by the subject, the forced oscillation technique is increasingly employed in routine lung function testing. However, comprehensive and device-independent values of respiratory impedance at baseline and after bronchodilation have not been established for healthy adults. The aim of this multicentre study...

Background: The constant-phase model (CPM) is commonly fit to respiratory system input impedance (Zrs) to estimate lung mechanics. Driving signal frequencies and the method of model fitting may influence the results, especially in cases of severe lung disease or under severe bronchoconstriction. Objective: To illustrate the effects of different...

During intestinal ischaemia-reperfusion, endotoxin can be translocated. Pretreatment with sublethal doses of endotoxin develops tolerance to ischaemia-reperfusion in different organs; however, the tolerance to intestinal ischaemia-reperfusion in the lung has rarely been investigated. Our aim was to study the role of endotoxin pretreatment in the me...

The relation between the progression of chronic obstructive pulmonary disease (COPD) and exacerbations is unclear. Currently, no animal model of acute exacerbation of COPD (AECOPD) exists. The objectives of this study were to evaluate the effects of mechanical forces induced by deep inspirations (DIs) on short-term deterioration of lung structure a...

The aim of this study was to evaluate airway structure-function relations in elastase-induced emphysema in rats. Sprague-Dawley rats were treated intratracheally with 50 IU porcine pancreatic elastase (PPE, n = 8) or saline (controls, n = 6). Six weeks later, lung volumes [functional residual capacity (FRC), residual volume (RV), and total lung cap...

The mechanical impedance of the respiratory system defines the pressure profile required to drive a unit of oscillatory flow into the lungs. Impedance is a function of oscillation frequency, and is measured using the forced oscillation technique. Digital signal processing methods, most notably the Fourier transform, are used to calculate impedance...

The mechanical impedance of the respiratory system defines the pressure profile required to drive a unit of oscillatory flow into the lungs. Impedance is a function of oscillation frequency, and is measured using the forced oscillation technique. Digital signal processing methods, most notably the Fourier transform, are used to calculate impedance...

to the editor: The continued use of and reports on “unrestrained plethysmography” ([5][1]), which is an attractively convenient and hence popular and easy-to-misuse method of respiratory monitoring, have evoked a vigorous negative response from the respiratory physiology community. Efforts have

The ability to maintain adequate gas exchange depends on the relatively homogeneous distribution of inhaled gas throughout the lung. Structural alterations associated with many respiratory diseases may significantly depress this function during tidal breathing. These alterations frequently occur in a heterogeneous manner due to complex, emergent in...