Forced Expiratory Maneuvers Research Articles

Medical Rehabilitation of Patients with Chronic Obstructive Pulmonary Disease Using Manipulative Action Techniques

This study was conducted to evaluate the efficiency of manipulative action techniques in complex treatment of patients with chronic obstructive pulmonary disease and represents the results of clinical and functional tests. Differentiated indications for use of different techniques of chest massage and manual therapy were proposed. Parallel group randomized prospective comparative study was conducted on 137 patients with COPD. In accordance with the classification (GOLD, 2013), all patients were diagnosed with COPD of medium severity. 75 (54.7%) patients had persistent disease, 80 (58.4%) and 57 (41.6%) patients suffered from respiratory insufficiency of I and II degree, respectively. Respiration function was assessed by pneumotachometry study performed during forced expiratory maneuvers and by spirometry methods; pulmonary hemodynamics and myocardial contractile function of the right ventricle were assessed by reopulmonography methods; central hemodynamics was assessed by tetrapolar thoracic rheography. The research led to the following overall findings. The massage technique focused on asymmetric areas of the chest develops the most active anti-inflammatory action as compared to other physical impact techniques we investigated. This technique should be used with caution in the presence of hypokinetic type of blood circulation and pulmonary hypertension. The classical massage technique of the chest has the advantage as we can consider the possibility to prescribe this technique to patients with more severe course of COPD, including but not limited to presence of pulmonary and systemic cardiac hemodynamic disorders, alveolar hypoxia.

Is forced oscillation technique the next respiratory function test of choice in childhood asthma.

Respiratory diseases, especially asthma, are common in children. While spirometry contributes to asthma diagnosis and management in older children, it has a limited role in younger children whom are often unable to perform forced expiratory manoeuvre. The development of novel diagnostic methods which require minimal effort, such as forced oscillation technique (FOT) is, therefore, a welcome and promising addition. FOT involves applying external, small amplitude oscillations to the respiratory system during tidal breathing. Therefore, it requires minimal effort and cooperation. The FOT has the potential to facilitate asthma diagnosis and management in pre-school children by faciliting the objective measurement of baseline lung function and airway reactivity in children unable to successfully perform spirometry. Traditionally the use of FOT was limited to specialised centres. However, the availability of commercial equipment resulted in its use both in research and in clinical practice. In this article, we review the available literature on the use of FOT in childhood asthma. The technical aspects of FOT are described followed by a discussion of its practical aspects in the clinical field including the measurement of baseline lung function and associated reference ranges, bronchodilator responsiveness and bronchial hyper-responsiveness. We also highlight the difficulties and limitations that might be encountered and future research directions.

VARIABILITY OF FORCED EXPIRATORY MANOEUVRE IN PATIENTS WITH ADVANCED NEUROMUSCULAR DISEASES

RespirologyVolume 22, Issue S3 p. 151-152 APSR Poster Abstracts VARIABILITY OF FORCED EXPIRATORY MANOEUVRE IN PATIENTS WITH ADVANCED NEUROMUSCULAR DISEASES First published: 23 November 2017 https://doi.org/10.1111/resp.13207_183Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume22, IssueS3Supplement: 22nd Congress of the Asian Pacific Society of Respirology, International Convention Centre, Sydney, Australia, 23–26 November 2017November 2017Pages 151-152 RelatedInformation

VARIATION OF PEAK EXPIRATORY FLOW RATE WITH BODY MASS INDEX IN THE FIRST YEAR MALE MEDICAL STUDENTS OF VISWABHARATHI MEDICAL COLLEGE, KURNOOL

Background: Obesity has become one of the major health issues in India. WHO defines obesity as “A condition with excessive fat accumulation in the body to the extent that the health and wellbeing are adversely affected”. Obesity results from a complex interaction of genetic, behavioral, environmental and socioeconomic factors causing an imbalance in energy production and expenditure. Peak expiratory flow rate is the maximum rate of airflow that can be generated during forced expiratory maneuver starting from total lung capacity. The simplicity of the method is its main advantage. It is measured by using a standard Wright Peak Flow Meter or mini Wright Meter. The pulmonary disorders due to obesity results in increased mortality and morbidity. Aims: To study the effect of Body Mass Index on Peak Expiratory Flow Rate in Medical students. Methods & Methods: study was performed on 60 Male age group of 17-22 Years, categorized as normal Weight BMI= 18.5-24.99kg/m2 and overweight BMI= 25-29.99 Kg/m2. There were 30 students with normal Weight BMI and 30 students with overweight BMI. Normal weight BMI subjects acted as control group to compare the Peak Expiratory Flow Rate with over weight. The parameters studied were weight, height, age, body mass index and Peak expiratory flow rate (PEFR). Student’s unpaired t-test was used for two group’s comparison. Results: The results of the investigation revealed a significantly lower Peak expiratory flow rate (PEFR) among the overweight BMI subjects compared to normal weight BMI subjects. Conclusion: Thus it is evident from the present study that obesity significantly affects the pulmonary functions which may give rise to long term complications and may lead to early morbidity and mortality.Key words: Peak Expiratory Flow Rate; Body Mass Index; Obesity.

Lung Function Monitoring; A Randomized Agreement Study.

Objective: To determine the agreement between devices and repeatability within devices of the forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF) and forced expiratory flow at 50% of FVC (FEF50) values measured using the four spirometers included in the study.Methods: 50 (24 women) participants (20-64 years of age) completed maximum forced expiratory flow manoeuvres and measurements were performed using the following devices: MasterScreen, SensorMedics, Oxycon Pro and SpiroUSB. The order of the instruments tested was randomized and blinded for both the participants and the technicians. Re-testing was conducted on a following day within 72 hours at the same time of the day.Results:The devices which obtained the most comparable values for all lung function variables were SensorMedics and Oxycon Pro, and MasterScreen and SpiroUSB. For FEV1, mean difference was 0.04 L (95% confidence interval; -0.05, 0.14) and 0.00 L (-0.06, 0.06), respectively. When using the criterion of FVC and FEV1 ≤ 0.150 L for acceptable repeatability, 67% of the comparisons of the measured lung function values obtained by the four devices were acceptable. Overall, Oxycon Pro obtained most frequently values of the lung function variables with highest precision as indicated by the coefficients of repeatability (CR), followed by MasterScreen, SensorMedics and SpiroUSB (e.g. min-max CR for FEV1; 0.27-0.46).Conclusion:The present study confirms that measurements obtained by the same device at different times can be compared; however, measured lung function values may differ depending on spirometers used.

Baroreceptor reflex during forced expiratory maneuvers in individuals with chronic spinal cord injury

Pulmonary and cardiovascular dysfunctions are leading causes of morbidity and mortality in patients with chronic Spinal Cord Injury (SCI). Impaired respiratory motor function and decreased Baroreflex Sensitivity (BS) are predictors for the development of cardiopulmonary disease. This observational case-controlled clinical study was undertaken to investigate if respiratory motor control deficits in individuals with SCI affect their ability to perform the Valsalva maneuver, and to determine if a sustained Maximum Expiratory Pressure (MEP) effort can serve as an acceptable maneuver for determination of the BS in the event that the Valsalva maneuver cannot be performed. The BS outcomes (ms/mmHg) were obtained using continuous beat-to-beat arterial blood pressure (BP) and heart rate (HR) recordings during Valsalva or MEP maneuvers in thirty nine individuals with chronic C3–T12 SCI. Twenty one participants (54%) reported signs of intolerance during the Valsalva maneuver and only 15 individuals (39%) were able to complete this task. Cervical level of injury was a significant risk factor (p=0.001) for failing to complete the Valsalva maneuver, and motor-complete injury was a significant risk factor for symptoms of intolerance (p=0.04). Twenty eight participants (72%) were able to perform the MEP maneuver; the other 11 participants failed to exceed the standard airway pressure threshold of 27cm H2O. Neither level nor completeness of injury were significant risk factors for failure of MEP maneuver. When the required airway pressure was sustained, there were no significant differences between BS outcomes obtained during Valsalva and MEP maneuvers. The results of this study indicate that individuals with high-level and motor-complete SCI are at increased risk of not completing the Valsalva maneuver and that baroreflex-mediated responses can be evaluated by using sustained MEP maneuver when the Valsalva maneuver cannot be performed.

New reference ranges for interpreting forced expiratory manoeuvres in infants and implications for clinical interpretation: a multicentre collaboration

The raised volume rapid thoracoabdominal compression (RVRTC) technique is commonly used to obtain full forced expiratory manoeuvres from infants, but reference equations derived from ‘in-house’ equipment have been shown to...

Lung Function Tests in Preschool Children.

The measurement of lung function by spirometry is routinely used to monitor and adequately treat children with asthma. The assessment and evaluation of lung function in children aged 3-5 years has been neglected for a long time because of the difficulty to perform forced expiratory maneuvers. However, the use of techniques such as the interrupter technique and the forced oscillation technique, which only require passive collaboration and where the only request to the child is to breathe at tidal volume, has overcome this limitation. Other techniques such as the measurement of specific airway resistance by plethysmography or the measurement of the lung clearance index using the multiple-breath washout might be helpful in this regard, although these techniques are less standardized in preschool children.

Determining respiratory system resistance and reactance by impulse oscillometry in obese individuals.

Objective: To evaluate peripheral respiratory system resistance and reactance (Rrs and Xrs, respectively) in obese individuals. Methods: We recruited 99 individuals, dividing them into four groups by body mass index (BMI): < 30.0 kg/m2 (control, n = 31); 30.0-39.9 kg/m2 (obesity, n = 13); 40.0-49.9 kg/m2 (severe obesity, n = 28); and ≥ 50.0 kg/m2 (morbid obesity, n = 13). Using impulse oscillometry, we measured total Rrs, central Rrs, and Xrs. Peripheral Rrs was calculated as the difference between total Rrs and central Rrs. All subjects also underwent spirometry. Results: Of the 99 individuals recruited, 14 were excluded because they failed to perform forced expiratory maneuvers correctly during spirometry. The individuals in the severe obesity and morbid obesity groups showed higher peripheral Rrs and lower Xrs in comparison with those in the two other groups. Conclusions: Having a BMI ≥ 40 kg/m2 was associated with a significant increase in peripheral Rrs and with a decrease in Xrs.

Metrological Aspects of Peak Expiratory Flow-Meters After Prolonged Use

SESSION TITLE: Pulmonary Physiology Posters SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, October 28, 2015 at 01:30 PM - 02:30 PM PURPOSE: There is scant information about the accuracy and reproducibility of the readings after prolonged use of mechanical peak expiratory flow-meters (PEF-meters) for monitoring of large airway function, both for clinical research purposes and routine management of asthma. The aim of this study was to test the reliability of peak expiratory flow (PEF) values measured with PEF-meters that have been used a prolonged period (two devices of five different types) using a clinical calibration procedure. METHODS: Five types of adult PEF-meters were tested before (new devices) and after a period of use of several years: Assess-Healthscan (8 years), Mini-Wright-Clement Clarke (7 years), Vitalograph-Vitalograph (5 years), PocketPeak-Ferraris (3 years) and Truzone-Monaghan (2 years). Comparisons with values from a Lily pneumotachograph (PT) (Pneumoscreen - E. Jaeger, Germany) were performed. In the first series of comparisons every PEF-meter was connected downstream in series with the PT and the same subject performed 40 partial to maximal forced expiratory maneuvers (MFEM), during a period of 160 minutes. In the second series of comparisons 30 adult patients performed randomized MFEM on each PEF-meter and on the PT, during a period of 30 minutes. RESULTS: ANOVA analysis revealed some differences in the accuracy of the different PEF-meters before and after a prolonged using period: the closest agreements to the PT before were Truzone and Mini-Wright, and after Assess and Mini-Wright. The best reproducibility for the before and after using period values was obtained in Assess and PocketPeak. CONCLUSIONS: The period for using of PEF-meters in a good conditions is much longer than that usually accepted and the replacement of PEF-meters should be restricted to cases of physical damage or obvious malfunction. Our results don't involve in any way the brand name of PEF-meters because we have the possibility to assess only two devices from every PEF-meters type and the number is statistically too small to characterise the brand name of PEF-meter type. CLINICAL IMPLICATIONS: These findings proved that PEF-meters can be used safely a longer period than expected, if their maintenance is flawless. DISCLOSURE: The following authors have nothing to disclose: Paraschiva Postolache, Octavian Petrescu, Floarea Mimi Nitu, Roxana Maria Nemes No Product/Research Disclosure Information

Impulse oscillometry in acute and stable asthmatic children: a comparison with spirometry

Objective: Lung function tests have attracted interest for the diagnosis and follow-up of childhood asthma in recent years. For patients who cannot perform forced expiratory maneuvers, impulse oscillometry (IOS), performed during spontaneous breathing, may be an alternative tool. Methods: Thirty-five acute, 107 stable asthmatic and 103 healthy children who presented to our clinic performed IOS followed by spirometry before and after salbutamol inhalation. The mean baseline and reversibility of IOS and spirometry parameters were compared between the groups. Correlation analyses were undertaken within the asthmatics, and the healthy controls separately. To distinguish the three groups, the sensitivity and specificity of baseline and reversibility values of IOS and spirometry were computed. When spirometry was taken as the gold standard, the discriminating performance of IOS to detect the airway obstruction and reversibility was investigated. Results: The mean absolute values of Zrs, R5, R5−R20, X5, X10, X15, Fres, AX, and all spirometric parameters, and the mean reversibility values of R5, R10, Fres, AX and forced expiratory volume in one second were different between the groups and the highest area under curve values to discriminate the groups was obtained from area of reactance (AX) and ΔAX. Zrs, all resistance (including R5−R20) and reactance parameters, Fres and AX were correlated with at least one spirometric parameter. Spirometric reversibility was detected by ≤−22.34 and ≤−39.05 cut-off values of ΔR5 and ΔAX, respectively. Conclusions: IOS has shown a highly significant association with spirometric indices and reversibility testing. It may be a substitute for spirometry in children who fail to perform forced expiratory maneuvers.

Analysis of Forced Expiratory Flow Signals Using the New Luus-Jaakola Optimization Procedure.

The aim of this study was to estimate forced vital capacity (FVC) by analyzing incomplete forced expiratory flow-time (FEFT) curves using the new Luus-Jaakola (NLJ) optimization procedure. Complete FEFT curves from 90 subjects with and without respiratory disease were used to validate the method, and its application performance was evaluated by FEFT curves containing incomplete curves from nine obstructive patients. First, a lumped parameter model of the FEFT curve, taking FVC as one of the model parameters, is chosen. The 0- 1 s, 0-1.5 s, . . . , 0-6 s curves chosen from the accepted FEFT curves are, respectively, taken as the local system observations. Then, the NLJ optimization procedure was used to get the estimate of FVC (FVCest) by estimating the model parameters. Finally, FVCest was compared with the measured FVC (FVCmea). The difference between FVCest and FVCmea decreased with the lengths of observed curves increasing. When the lengths of observed curves reached 3 s, the mean difference (±SD) between FVCest and FVCmea was -11 ± 58 mL. Estimated FVC derived from the incomplete curves were close to FVC from accepted maneuvers. The method can be used to estimate FVC by analyzing an incomplete FEFT curve, providing the length of the curve is more than 3 s. This method can help the subjects who cannot complete the forced expiratory maneuver to provide a reliable estimate of FVC and also can be used to analyze the unacceptable spirometry because of early termination of exhalation.

Inhaled Salmeterol Induces Salivary Alpha Amylase Activity in Healthy Subjects

FEBRUARY 2015 AB4 Abstracts S A T U R D A Y 12 Inhaled Salmeterol Induces Salivary Alpha Amylase Activity in Healthy Subjects Andrea A. Pappalardo, MD, Sherlyana Surja, MD, Caitlin M. Campion, Sarah J. Aldrich, James N. Moy, MD; Asthma and Allergy Center, Bloomingdale, IL, Rush University Medical Center, Chicago, IL, John H. Stroger Hospital of Cook County, Chicago, IL. RATIONALE: Salivary alpha-amylase (sAA) secretion is an indirect method of measuring beta-receptor activation. Increases in sAA are seen in isoproterenol-infused mice (attenuated by beta-receptor antagonists) and in humans under physical or mental stress. We previously demonstrated that albuterol given by inhalation increases sAA (peaking at 15 minutes) in healthy volunteers and patients with asthma. We hypothesized that inhaled salmeterol, but not the anticholinergic ipratropium, will induce sAA secretion. METHODS: Five healthy volunteers were enrolled. Spirometry was performed; and sAA, blood pressure and heart rate were collected at baseline and at 15, 30, 60 and 120 minutes after inhalation of fluticasonesalmeterol HFA (90 mcg/42 mcg). Two weeks later, two of the subjects repeated the protocol after inhaling ipratropium (34mcg). Three additional subjects performed spirometry maneuvers alone to confirm stability of sAA during forced expiratory maneuvers. RESULTS: Baseline sAAwas 143651 (U/mL6SEM) , which increased after salmeterol inhalation to 190657, 230668, 2766100, and 239670 at 15, 30, 60, and 120minutes, respectively; peaking at 60minutes (p<0.05 at 60 and 120 minutes; ANOVA). sAA did not change after ipratropium inhalation or spirometry alone. FEV1 did not change from baseline after inhalation of salmeterol or ipratropium in these healthy volunteers. No significant changes in blood pressure and heart rate were observed in any group. CONCLUSIONS: Salmeterol induces sAA in healthy subjects, but peaks later than albuterol, consistent with its pharmacokinetic properties. These findings reinforce the concept that sAA is a surrogate marker for beta-2receptor activation and may be useful in assessing tachyphylaxis or unresponsiveness to beta-2-agonists.

Diagnosis and early detection of COPD using spirometry.

The standard respiratory function test for case detection of chronic obstructive pulmonary disease (COPD) is spirometry. The criterion for diagnosis defined in guidelines is based on the FEV1/FVC ratio forced expiratory ratio (FER) and its severity is based on forced expiratory volume in one second (FEV1) from measurements obtained during maximal forced expiratory manoeuvres. Spirometry is a safe and practical procedure, and when conducted by a trained operator using a spirometer that provides quality feedback, the majority of patients can be coached to provide acceptable and repeatable results. This allows potentially wide application of testing to improve recognition and diagnosis of COPD, such as for case finding in primary care. However, COPD remains substantially under diagnosed in primary care and a major reason for this is underuse of spirometry. The presence of symptoms is not a reliable indicator of disease and diagnosis is often delayed until more severe airflow obstruction is present. Early diagnosis is worthwhile, as it allows risk factors for COPD such as smoking to be addressed promptly and treatment optimised. Paradoxically, investigation of the patho-physiology in COPD has shown that extensive small airway disease exists before it is detectable with conventional spirometric indices, and methods to detect airway disease earlier using the flow-volume curve are discussed.

An Australian national panel study of diurnal temperature range and children's respiratory health

BackgroundIt is still uncertain whether diurnal temperature range (DTR) affects children's respiratory function. ObjectiveTo examine the effects of DTR on lung function and respiratory symptoms for school children with asthma in Australia. MethodsA panel of 270 children (ages 7-12 years) with asthma living in 6 Australian cities was recruited. They were asked to perform 3 successive forced expiratory maneuvers using a portable electronic peak flow meter twice daily for 4 weeks. The highest values for peak expiratory flow (PEF) were stored for each session. At the same time, they were asked to record their respiratory symptoms (eg, cough and/or phlegm and wheeze and/or chest tightness) every day in the morning (for nighttime symptoms) and evening (for daytime symptoms). Daily data on different metrics of ambient temperature and air pollution were obtained from fixed monitors nearby. Relative humidity data were downloaded from the Weather Underground website. Mixed models, adjusting for children's individual characteristics and air pollution, were used to examine the effects of DTR on PEF and respiratory symptoms. ResultsDTR had linear effects on PEF and respiratory symptoms. An increase in DTR induced a reduction in PEF and increased the occurrence of respiratory symptoms. In general, the effects lasted for 3 days (lag, 0-2 days). The effects occurred for both boys and girls. ConclusionOur findings provide evidence that DTR had significant effects on lung function and respiratory symptoms for children with asthma. These results indicate that it is important and necessary to protect children with asthma from the effect of unstable weather.

Ambient temperature and lung function in children with asthma in Australia

The association between ambient temperature and lung function in children with asthma is still uncertain. A panel of 270 children (aged 7-12 years) with asthma was recruited from six Australian cities. They performed three successive forced expiratory manoeuvres twice daily for 4 weeks. The highest peak expiratory flow rate (PEF) and forced expiratory volume in 1 s (FEV1) were stored for each session. During the same period, data were obtained daily on ambient temperature, relative humidity and air pollution. Mixed models were used to examine the effects of temperature on lung function, controlling for individual characteristics and environmental factors. Ambient temperature was negatively related to both morning and evening PEF and FEV1 for 0-3 days lag. In general, the effects of temperature were stronger in males than in females for evening PEF, while the effects were stronger in females for evening FEV1. Children with asthma living in southern cities were more sensitive to high temperature than those in the northernmost city. Higher ambient temperature is associated with lower lung function in children with asthma. Preventive health policies will be required to protect children with asthma from increasingly frequent high temperatures.

LUNOKID: can numerical American Thoracic Society/European Respiratory Society quality criteria replace visual inspection of spirometry?

The gold standard for assessing quality of forced expiratory manoeuvres is visual inspection by an expert. American Thoracic Society/European Respiratory Society numerical quality criteria (NQC) include back-extrapolated volume (BEV), repeatability and forced expiratory time (FET). Equipment currently available provides feedback tempting the investigator to use NQC as pass-fail criterion. To investigate whether using NQC instead of visual acceptability is a valid option, we analysed data from a multicentre national reference study in Germany of children aged 4-18 years. Spirometry was performed under field conditions. Receiver operating characteristic analysis was used to assess performance of BEV, repeatability, FET and a combination thereof in relation to visual acceptability. We included data from 3133 healthy Caucasians in the analyses; 72% delivered at least two visually acceptable manoeuvres. Of these, 59% would have been rejected based on combined NQC, mainly because the FET criterion was not feasible. Specificity of the NQC was generally low (BEV 10%, repeatability 30% and FET 50%). Receiver operating characteristic analysis showed that a combination of the three measures could reach at best a sensitivity of 90% and specificity of 56%. We conclude that visual control is mandatory and NQC may help obtain the best possible results, but a fixed cut-off for FET should be abandoned.

Study on the use of impulse oscillometry in the evaluation of children with asthma

Objective The aim of this study was to determine the use of impulse oscillometry in the evaluation of children with asthma and to analyze lung parameters, order effect, and utility, compared with spirometry. Background Asthma is a disease characterized by ongoing inflammation of the airway, overproduction of mucus, and airway constriction due to tightened muscles, which results in permanent structural changes in the lungs, a condition often called airway remodeling. In turn, these changes usually lead to accelerated declines in lung function, including irreversible decreases in airflow because of narrowed air passages. The Impulse Oscillometry System measures respiratory impedance using short pulses (impulses) of air pressure. Impulse oscillometry has been used with success to assess lung function in healthy and asthmatic children, as well as in adolescents. Materials and methods This case-control study was carried out on 66 children divided into two groups: group 1 included 46 children who were previously diagnosed as asthmatic, and group II (control group) included 20 children without a history of asthma. All studied children were subjected to full history taking; clinical evaluation, including general examination and local chest examination; pulmonary function testing; impulse oscillometry before and after spirometry. Pulmonary function testing (impulse oscillometry and spirometry) was repeated in group 1 after bronchodilator administration. Results Asthma prevalence was increased among children with a family history of atopy and among those with family members who smoked. Postbronchodilator impulse oscillometry results were significant, especially R5% and X5pred.-X5. Performing forced expiratory maneuvers during spirometry causes a marked decrease in lung function, detected using impulse oscillometry. Conclusion Impulse oscillometry is useful in the evaluation of children with asthma.

Technical Assessment of Spirometers Connected in Series

Office spirometers are now widely used to detect obstructive lung diseases. To test the technical characteristics of these devices, simulation of different forced expiratory maneuvers is performed, using computer generated waveforms. However, the tests with human subjects are also useful to detect technical flaws. The procedure used by some authors to test the accuracy of office spirometers is to compare measurements made by 2 spirometers connected in series. The aim of this study was to evaluate the accuracy of this latter procedure. Two sets of 2 spirometers connected in series were used: the PocketSpiro with the MicroLoop, and the PocketSpiro with the SpiroScout. Different standard American Thoracic Society curves were selected for both ambient temperature and pressure (ATP) and body temperature and pressure saturated (BTPS) conditions and generated with a waveform simulator. We compared lung function indices (FVC, peak expiratory flow, and FEV(1)) recorded by the PocketSpiro when it was placed respectively upstream or downstream in the assembly. In ATP conditions, lung function indices were generally higher when the spirometer was placed downstream rather than upstream. The observed deviations reached up to 10%. In BTPS conditions, lung function indices were underestimated when the spirometer was placed downstream, as compared to the ATP procedure. The modification of the flow characteristics and the temperature drop are the 2 mechanisms that could explain our results. Connecting the spirometers in series gives variable results, depending on the position of the spirometer in the assembly. Individual tests are therefore essential, as results are not interchangeable.

Tracheobronchoplasty for the treatment of tracheobronchomalacia

Patients with tracheobronchomalacia (TBM) typically present with dyspnea, recurrent infections, intractable cough, or retained secretions. Airway stabilization may be accomplished with silicone stenting, which provides patients with symptom relief in a minimally invasive manner. However, this technique is not without complications, which mostly occur by 3 weeks. Surgical stabilization is the definitive treatment of TBM. We review the evaluation of TBM and options for treatment.