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European Respiratory Review : An... Mar 2022Recently, "Technical standards for respiratory oscillometry" was published, which reviewed the physiological basis of oscillometric measures and detailed the technical... (Review)
Review
Recently, "Technical standards for respiratory oscillometry" was published, which reviewed the physiological basis of oscillometric measures and detailed the technical factors related to equipment and test performance, quality assurance and reporting of results. Here we present a review of the clinical significance and applications of oscillometry. We briefly review the physiological principles of oscillometry and the basics of oscillometry interpretation, and then describe what is currently known about oscillometry in its role as a sensitive measure of airway resistance, bronchodilator responsiveness and bronchial challenge testing, and response to medical therapy, particularly in asthma and COPD. The technique may have unique advantages in situations where spirometry and other lung function tests are not suitable, such as in infants, neuromuscular disease, sleep apnoea and critical care. Other potential applications include detection of bronchiolitis obliterans, vocal cord dysfunction and the effects of environmental exposures. However, despite great promise as a useful clinical tool, we identify a number of areas in which more evidence of clinical utility is needed before oscillometry becomes routinely used for diagnosing or monitoring respiratory disease.
Topics: Airway Resistance; Asthma; Humans; Oscillometry; Respiratory Function Tests; Spirometry
PubMed: 35140105
DOI: 10.1183/16000617.0208-2021 -
Intensive Care Medicine Jun 2020
Topics: Airway Resistance; Betacoronavirus; COVID-19; Comorbidity; Coronavirus Infections; Guidelines as Topic; Humans; Hypoxia; Lung; Lung Compliance; Organ Size; Pandemics; Phenotype; Pneumonia, Viral; Radiography, Thoracic; Respiratory Dead Space; SARS-CoV-2; Severity of Illness Index; Ventilation-Perfusion Ratio
PubMed: 32291463
DOI: 10.1007/s00134-020-06033-2 -
Respiratory Care May 2021In mechanically ventilated subjects, intra-tracheal secretions can be aspirated with either open suction systems (OSS) or closed suction systems (CSS). In contrast to... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
In mechanically ventilated subjects, intra-tracheal secretions can be aspirated with either open suction systems (OSS) or closed suction systems (CSS). In contrast to CSS, conventional OSS require temporarily disconnecting the patient from the ventilator, which briefly diminishes PEEP and oxygen supply. On the other hand, CSS are more expensive and less effective at aspirating secretions. Thus, it was hypothesized that the 2 procedures differentially affect pulmonary and cardiovascular parameters after suction.
METHODS
Subjects in the ICU ( = 66) were quasi-randomized for initial treatment with OSS or CSS in a crossover design. To compare the potential for these suction systems to compromise cardiorespiratory stability, changes in cardiopulmonary physiology were assessed from before to just after use of each suction system (three 10-s aspirations).
RESULTS
For most pulmonary and cardiovascular parameters (ie, peak inspiratory pressure, airway resistance, pressure plateau, heart rate, and arterial pressures), the effects of aspiration inversely correlated with baseline values for that parameter, with a similar regression slope between suction systems. However, when controlling for baseline values, OSS caused significantly greater increases in airway resistance and peak inspiratory pressure ( < .001 and < .01 vs CSS, respectively).
CONCLUSIONS
Elevated airway resistance prior to endotracheal suction may justify use of a CSS and contraindicate a conventional OSS in mechanically ventilated subjects. Adoption of this approach into clinical guidelines may prevent suction-induced pulmonary injury in subjects, especially for those with underlying diseases involving increased airway resistance or increased alveolar pressure. (ClinicalTrials.gov registration: NCT03256214.).
Topics: Humans; Intubation, Intratracheal; Respiration, Artificial; Respiratory Physiological Phenomena; Suction; Trachea
PubMed: 33688090
DOI: 10.4187/respcare.08511 -
Respiratory Medicine Mar 2015Breathing out against resistance, in order to achieve positive expiratory pressure (PEP), is applied by many patient groups. Pursed lips breathing and a variety of... (Review)
Review
Breathing out against resistance, in order to achieve positive expiratory pressure (PEP), is applied by many patient groups. Pursed lips breathing and a variety of devices can be used to create the resistance giving the increased expiratory pressure. Effects on pulmonary outcomes have been discussed in several publications, but the expected underlying physiology of the effect is seldom discussed. The aim of this article is to describe the purpose, performance, clinical application and underlying physiology of PEP when it is used to increase lung volumes, decrease hyperinflation or improve airway clearance. In clinical practice, the instruction how to use an expiratory resistance is of major importance since it varies. Different breathing patterns during PEP increase or reduce expiratory flow, result in movement of EPP centrally or peripherally and can increase or decrease lung volume. It is therefore necessary to give the right instructions to obtain the desired effects. As the different PEP techniques are being used by diverse patient groups it is not possible to give standard instructions. Based on the information given in this article the instructions have to be adjusted to give the optimal effect. There is no consensus regarding optimal treatment frequency and number of cycles included in each treatment session and must also be individualized. In future research, more precise descriptions are needed about physiological aims and specific instructions of how the treatments have been performed to assure as good treatment quality as possible and to be able to evaluate and compare treatment effects.
Topics: Airway Resistance; Breathing Exercises; Dyspnea; Humans; Lung Volume Measurements; Positive-Pressure Respiration; Pulmonary Disease, Chronic Obstructive; Pulmonary Gas Exchange; Treatment Outcome; Vital Capacity; Work of Breathing
PubMed: 25573419
DOI: 10.1016/j.rmed.2014.11.003 -
Cardiovascular Toxicology Oct 2019The use of electronic cigarettes has increased exponentially since its introduction onto the global market in 2006. However, short- and long-term health effects remain... (Randomized Controlled Trial)
Randomized Controlled Trial
The use of electronic cigarettes has increased exponentially since its introduction onto the global market in 2006. However, short- and long-term health effects remain largely unknown due to the novelty of this product. The present study examines the acute effects of e-cigarette aerosol inhalation, with and without nicotine, on vascular and pulmonary function in healthy volunteers. Seventeen healthy subjects inhaled electronic cigarette aerosol with and without nicotine on two separate occasions in a double-blinded crossover fashion. Blood pressure, heart rate, and arterial stiffness measured by pulse wave velocity and pulse wave analysis were assessed at baseline, and then at 0 h, 2 h, and 4 h following exposure. Dynamic spirometry and impulse oscillometry were measured following vascular assessments at these time points, as well as at 6 h following exposure. e-Cigarette aerosol with nicotine caused a significant increase in heart rate and arterial stiffness. Furthermore, e-cigarette aerosol-containing nicotine caused a sudden increase in flow resistance as measured by impulse oscillometry, indicating obstruction of the conducting airways. Both aerosols caused an increase in blood pressure. The present study indicates that inhaled e-cigarette aerosol with nicotine has an acute impact on vascular and pulmonary function. Thus, chronic usage may lead to long-term adverse health effects. Further investigation is warranted.
Topics: Administration, Inhalation; Adult; Aerosols; Airway Obstruction; Airway Resistance; Blood Pressure; Cardiovascular System; Cross-Over Studies; Double-Blind Method; Electronic Nicotine Delivery Systems; Female; Healthy Volunteers; Heart Rate; Hemodynamics; Humans; Lung; Male; Nicotine; Nicotinic Agonists; Risk Assessment; Time Factors; Vaping; Vascular Stiffness; Young Adult
PubMed: 30963443
DOI: 10.1007/s12012-019-09516-x -
Pneumonologia I Alergologia Polska 2016Airway resistance is the ratio of driving pressure to the rate of the airflow in the airways. The most frequent methods used to measure airway resistance are whole-body... (Review)
Review
Airway resistance is the ratio of driving pressure to the rate of the airflow in the airways. The most frequent methods used to measure airway resistance are whole-body plethysmography, the interrupter technique and the forced oscillation technique. All these methods allow to measure resistance during respiration at the level close to tidal volume, they do not require forced breathing manoeuvres or deep breathing during measurement. The most popular method for measuring airway resistance is whole-body plethysmography. The results of plethysmography include among others the following parameters: airway resistance (Raw), airway conductance (Gaw), specific airway resistance (sRaw) and specific airway conductance (sGaw). The interrupter technique is based on the assumption that at the moment of airway occlusion, air pressure in the mouth is equal to the alveolar pressure . In the forced oscillation technique (FOT), airway resistance is calculated basing on the changes in pressure and flow caused by air vibration. The methods for measurement of airway resistance that are described in the present paper seem to be a useful alternative to the most common lung function test - spirometry. The target group in which these methods may be widely used are particularly the patients who are unable to perform spirometry.
Topics: Airway Resistance; Asthma; Female; Forced Expiratory Volume; Humans; Male; Plethysmography, Whole Body; Respiratory Function Tests; Spirometry
PubMed: 27238174
DOI: 10.5603/PiAP.2016.0014 -
BioMed Research International 2015
Topics: Airway Management; Airway Resistance; Emergency Medicine; Humans; Intubation, Intratracheal; Respiration, Artificial
PubMed: 26199941
DOI: 10.1155/2015/425715 -
Respiratory Physiology & Neurobiology Oct 2023Oscillometry has been around for almost 70 years, but there are still many unknowns. The test is performed during tidal breathing and is therefore free from... (Review)
Review
Oscillometry has been around for almost 70 years, but there are still many unknowns. The test is performed during tidal breathing and is therefore free from patient-dependent factors that could influence the results. The Forced Oscillation Technique (FOT), which requires minimal patient cooperation, is gaining ground, particularly with elderly patients and children. In pulmonology, it is a valuable tool for assessing obstructive conditions (with a distinction between central and peripheral obstruction) and restrictive disorders (intrapulmonary and extrapulmonary). Its sensitivity allows the assessment of bronchodilator and bronchoconstrictor responses. Different lung diseases show different patterns of changes in FOT, especially studied in asthma and chronic obstructive pulmonary disease. Because of these differences, many studies have analysed the usefulness of this technique in different areas of medicine. In this paper, the authors would like to present the basics of oscillometry with the areas of its most recent clinical applications.
Topics: Child; Humans; Aged; Airway Resistance; Oscillometry; Asthma; Pulmonary Disease, Chronic Obstructive; Respiratory Function Tests; Spirometry; Forced Expiratory Volume
PubMed: 37536553
DOI: 10.1016/j.resp.2023.104135