Lung Clearance Index Measurements Research Articles

LCI measurement is coming of age

Background: Lung clearance index (LCI) derived from multiple-breath washout (MBW) is an established proxy of small airways function in children with cystic fibrosis (CF). Yet, LCI has not been systematically studied in adults with prevalent chronic lung diseases using available and validated MBW setups and protocols.

Lung Clearance Index is Increased in Patients with COPD - LCI Measurements in the Daily Routine

Objective: The lung clearance index (LCI), an index of ventilation homogeneity derived from the multiple breath wash out (MBW) of an inert gas, is a lung function test to monitor pulmonary disease. The aim of this study was to investigate whether LCI measurements are suitable for the daily routine in patients with COPD in comparison to young and healthy controls. Methods: MBW measurements were performed successfully in 23 patients (out of 42) patients with COPD (FEV1 %, 40.41 ± 14.65). As controls we selected 30 healthy and young volunteers. All subjects used the EasyOne ProLab™ (ndd, Switzerland). Results: 18 patients were not able to finish measurements successfully because of significant leaks, cough and irregular breathing (GOLD I n=1 (5.6%); GOLD II n=6 (33.3%); GOLD III n=5 (27.7%); GOLD IV n=6 (33.3%). The mean LCI was significantly higher in COPD patients as compared to young and healthy volunteers (12.55 ± 3.50 vs 7.00 ± 1.02, p<0.05). Although LCI correlated with FEV1 %of predicted (r²=-0.540, p<0.01) and Rtot (% pred.) (r²=0.504, p<0.01) the method failed to discriminate between GOLD II-IV classes. LCI correlated with the volume of trapped gas in elderly patients with COPD and young and healthy controls [FRC (% pred.) (r²=0.191, p<0.01), ITGV (% pred.) (r²=0.478, p<0.01), and RV (% pred.) (r²=0.462, p<0.01)]. Moreover, the results did not correlate with the 6-MWT, a validated clinical outcome parameter. Conclusions: Although measurement of LCI was capable to detect inhomogeneous ventilation (airway obstruction and hyperinflation), this method did not discriminate between GOLD II-IV and did not correlate with 6-MWT. More than 43% of the patients with COPD did not complete the study because of difficulties with the method. Nevertheless, the LCI might be a tool to gain insight into lung pathophysiology in younger patients e.g. children. Our preliminary study encourages further investigations for the future.

Research is the Future, the Future is……

Over the past two decades, Professor Lenney has established the Paediatric Respiratory Department at the Royal Stoke University Hospital as a centre recognised for high quality research. A broad portfolio of clinical and laboratory based research is in progress. Four research areas are discussed that are likely to contribute to the continued academic output from the unit. These are the use of selected ion flow tube mass spectrometry for the detection of biomarkers associated with pulmonary pathogens, the measurement of lung clearance index in preschool children, structured light plethysmography in children and the use of oral prednisolone for asthma exacerbations in children.

Functional residual capacity and lung clearance index in infants treated for esophageal atresia and tracheoesophageal fistula

BackgroundNewborn babies with esophageal atresia/tracheoesophageal fistula (EA/TEF) are prone to respiratory tract disorders. Functional residual capacity (FRC) and lung clearance index (LCI) are commonly considered useful and sensitive tools to investigate lung function and early detecting airways diseases. The aim of the present study is to report the first series of EA/TEF infants prospectively evaluated for FRC and LCI. MethodsProspective observational cohort study of all patients treated for EA/TEF. Lung volume and ventilation inhomogeneity were measured by helium gas dilution technique using an ultrasonic flow meter. Babies were studied both in assisted controlled ventilation (sedated) and in spontaneous breathing (quiet sleep). Three consecutive FRC and LCI measurements were collected for each test at three different time points: before surgery (T0), 24hours after surgery (T1) and after extubation (T2). Results16 EA newborns were eligible for the study between December 2011 and July 2013. Three were excluded because of technical problems. At T0 FRC values were in the normal range regardless the presence of TEF but worsened afterwards at T1, with a subsequent recovering after extubation; a significant improvement after surgery was observed concerning LCI while no differences were found in tidal volume. ConclusionHelium gas dilution technique is a suitable method to measure the effect of surgery on lung physiology, even in ventilated infants with EA. The changes observed could be related to the ventilatory management and lung compression during surgical procedure.

Long-term improvement of lung clearance index in patients with mild cystic fibrosis lung disease: Does hypertonic saline play a role?

To assess whether long-term inhalation with hypertonic saline is able to halt the progression of mild CF lung disease, we analysed longitudinal data of lung clearance index (LCI) and spirometry. A total of 34 patients with mild lung disease (FEV1≥70% of predicted) had at least one LCI result before and ≥2 LCI measurements after start of hypertonic saline (HS) therapy. After a mean follow-up of 39.7 (SD 7.4) months after starting HS, LCI improved significantly from 7.89 (SD 1.35) at baseline to 6.96 (SD 1.03), and 19/34 patients had a normal LCI value at the last measurement. No decrease in mean FEV1 was observed. Thus, ventilation inhomogeneity can improve in patients with mild lung disease.

Impact of Software Settings on Multiple-Breath Washout Outcomes.

Background and ObjectivesMultiple-breath washout (MBW) is an attractive test to assess ventilation inhomogeneity, a marker of peripheral lung disease. Standardization of MBW is hampered as little data exists on possible measurement bias. We aimed to identify potential sources of measurement bias based on MBW software settings.MethodsWe used unprocessed data from nitrogen (N2) MBW (Exhalyzer D, Eco Medics AG) applied in 30 children aged 5–18 years: 10 with CF, 10 formerly preterm, and 10 healthy controls. This setup calculates the tracer gas N2 mainly from measured O2 and CO2concentrations. The following software settings for MBW signal processing were changed by at least 5 units or >10% in both directions or completely switched off: (i) environmental conditions, (ii) apparatus dead space, (iii) O2 and CO2 signal correction, and (iv) signal alignment (delay time). Primary outcome was the change in lung clearance index (LCI) compared to LCI calculated with the settings as recommended. A change in LCI exceeding 10% was considered relevant.ResultsChanges in both environmental and dead space settings resulted in uniform but modest LCI changes and exceeded >10% in only two measurements. Changes in signal alignment and O2 signal correction had the most relevant impact on LCI. Decrease of O2 delay time by 40 ms (7%) lead to a mean LCI increase of 12%, with >10% LCI change in 60% of the children. Increase of O2 delay time by 40 ms resulted in mean LCI decrease of 9% with LCI changing >10% in 43% of the children.ConclusionsAccurate LCI results depend crucially on signal processing settings in MBW software. Especially correct signal delay times are possible sources of incorrect LCI measurements. Algorithms of signal processing and signal alignment should thus be optimized to avoid susceptibility of MBW measurements to this significant measurement bias.

EPS04.3 Comparison of CF and non-CF LCI results using the Exhalyzer D and Innocor™ devices

Background Multiple breath washout (MBW) is a pulmonary function test that allows measurement of lung clearance index (LCI), a marker of ventilation heterogeneity. LCI is increasingly being considered as a clinical trial outcome measure. The Exhalyzer D N 2 washout (N 2 /ExD, Ecomedics AG, Switzerland) is the recommended technique by the ECFS CTN. Mostly our group's experience with LCI uses the Innocor™ gas analyser (Innovision, Denmark), SF6 as a tracer gas (SF6/Inn). To understand the N 2 /ExD technique, the aims of this study were to compare (a) intra-test variability; (b) LCI values, (c) LCI & FEV1 for the two techniques. Methods 21 CF (14F, mean 20±12 yrs) and 10 non-CF (8F, mean 28±10 yrs) have completed MBW trials with the 2 techniques in random order on the same visit; methods previously described (Horsley et al. 2009, Jensen et al. 2013). Results Intra-test CoV (2–3repeats) was similar for SF 6 /Inn and N 2 /ExD (3.57 vs 3.78 CF, ns). LCI was significantly higher with N 2 /ExD than with SF 6 /Inn in both CF (14.05 vs 9.33; p≤0.0001) and non-CF (7.08 vs 6.64, p=0.04). Both techniques show a significant correlation for LCI and FEV 1 %, although the regression slopes were significantly different (p = 0.005); much steeper for N 2 /ExD. Conclusions LCI values cannot be used interchangeably between the Innocor™ and Exhalyzer D. In non CF, there was a statistically significant difference, with higher values in the N 2 /ExD. The difference was much greater in CF and increased as LCI did. In the context of similar intra-test variability, the hypothesis that this may translate into improved power in future clinical trials needs to be tested. Sponsored by a non-restricted grant from Novartis.

WS21.3 Acute changes in the lung clearance index after physiotherapy in children with cystic fibrosis

Objectives The lung clearance index (LCI) is becoming a prominent endpoint for assessing interventions in cystic fibrosis (CF) concurrent with daily physiotherapy. We examined the acute time-course of change in LCI following positive expiratory pressure (PEP) chest physiotherapy in children with an acute pulmonary exacerbation of CF. Methods To assess the repeatability of our LCI measurements, 71 children, aged 8–18, with stable CF performed multiple-breath nitrogen washout (MBNW) reporting LCI. For the main study, 39 children, aged 8–18, admitted for acute exacerbations of CF were recruited on day 5 of admission to perform MBNW, spirometry and body plethysmography prior to supervised PEP. MBNW was then performed immediately after PEP, and at 1, 2 and 3 hours post-intervention. All lung function tests were repeated 24 hours after baseline measurement. Results Repeatability, expressed as the coefficient of variation (CoV), of LCI was 6.1(3.2)% in subjects with stable CF and 8.7(3.4)% in those with a pulmonary exacerbation. PEP significantly increased LCI, peaking at 1 hour post-intervention (8.82 to 9.81, p Conclusion The CoV for LCI was low in stable CF but increased in those with pulmonary exacerbations. In subjects with a pulmonary exacerbation of CF, ventilation inhomogeneity (LCI) acutely increases after physiotherapy on a background of overall improvement over 24 hours. This indicates standardisation of time of LCI measurement with respect to physiotherapy is required.

Effect of equipment dead space on multiple breath washout measures.

Multiple breath inert gas washout (MBW) systems are designed to minimize equipment dead space volume (Vd). Animal and infant studies have demonstrated the impact of increased Vd on MBW measurements. In this study, we investigate the effect of Vd of a nitrogen (N2 ) MBW system on MBW measurements in preschool children. N2 MBW measurements were performed in healthy adults under standard conditions; Vd was added to match the relationship between Vd and lung volumes observed in preschool children. Subsequently, subjects were measured on a sulfur hexafluoride (SF6 ) MBW system under standard conditions and with Vd added to match that of the N2 MBW system. Healthy preschool children and children with cystic fibrosis were tested on both the N2 MBW and SF6 MBW in random order on the same day. A correction equation was derived based on the adult experiments and tested on the preschool data. Increasing the Vd of the N2 MBW system resulted in a higher lung clearance index (LCI). A strong non-linear relationship between N2 LCI and the Vd/tidal volume was observed. When the Vd was equivalent between systems, LCI measured by the SF6 MBW system was similar to that measured by the N2 MBW. LCI was higher on the N2 MBW than the SF6 MBW in preschool children. Correcting for the equipment Vd of the N2 MBW resulted in better agreement. Equipment Vd affects LCI measurements especially in young children where Vd is large relative to lung volumes.

P205 Multiple Breath Washouts In Children Can Be Significantly Shortened Without Compromising Measurement Quality

Background Multiple-breath washout (MBW) is used to calculate a measure of ventilation heterogeneity, the lung clearance index (LCI), and requires tidal breathing until a previously inspired tracer gas concentration falls below 1/40th of the initial value, an arbitrary threshold. LCI is usually performed in triplicate, each taking 4–8 min to complete which may be taxing, particularly in young children and those with marked airflow obstruction. Shortened LCI is of interest since a reduction in the test time may increase feasibility and improve the clinical applicability of the measurement. We hypothesised that LCI measurements could be reliably shortened. We also investigated whether shortened MBW was responsive to an intervention. Patients and methods We calculated LCI from a fixed time point, and from a fixed number of breaths, as well as LCI and 25% (LCI0.25), 50% (LCI0.5) and 75% (LCI0.75) of 1/40th of the initial concentration of tracer gas (LCIstd) and the time saved, in children aged 6–16 years with asthma (n = 21), cystic fibrosis (CF, n = 20) and primary ciliary dyskinesia (PCD, n = 19), and healthy controls (n = 17), aged 3–18 years. Shortened LCI was also calculated in 29 asthmatic children pre and one month post one intra-muscular triamcinolone injection, part of our clinical severe asthma protocol. Results Calculating shortened LCI from a fixed washout time or breath number was not reliable. However, all shortened LCI measurements from initial gas concentration correlated significantly with LCIstd in each disease group. LCI0.5 presented a balance between correlation with LCIstd (see figure) and time-saving. Mean proportion of time saved per washout, using LCI0.5, was 27% (asthma), 28% (CF) and 31% (PCD). Furthermore, LCI0.5 was significantly reduced after triamcinolone in children with severe asthma (mean LCI0.5 pre, 5.5 and 5.1 post triamcinolone, p = 0.02), and the change was similar to that demonstrated using LCIstd (mean LCIstd pre, 7.8 and post 7.0, p = 0.001). Conclusion We show for the first time that LCI measurements can be shortened without loss of information in school-children with asthma, CF and PCD. LCI0.5 was the optimal surrogate measure for LCIstd when proportion of time saved, correlation with LCIstd and change following an intervention were considered.

Lung clearance index: should we really go back to nitrogen washout?

To the Editor: A recent editorial in the European Respiratory Journal [1] recognises that the fundamental scientific data on lung clearance index (LCI) obtained by sulfur hexafluoride (SF6) multiple-breath washout (MBW) have paved the way for clinical use of LCI. Although the editorial stresses the need for standardisation, it also appears to suggest that SF6 can be replaced by nitrogen (N2) as the washout gas. We (Innovision ApS, Odense, Denmark) are the manufacturer of the AMIS 2000 medical mass spectrometer system that, using user-specific software and hardware, was adapted to perform MBW. The AMIS 2000-based devices are now considered the “gold standard” device for SF6 LCI measurements in cystic fibrosis patients by opinion leaders in the field [2]. This device has been used in the vast majority of studies demonstrating the clinical value of SF6 LCI in cystic fibrosis patients, with one recent notable exception: the demonstration of the change in LCI caused by Ivacaftor in cystic fibrosis patients with normal forced expiratory volume in 1 s, where a prototype version of our other system, Innocor, adapted for open-circuit SF6 LCI, was used [3]. The AMIS 2000 adapted MBW system is too …

S41 Impact of alveolar nitrogen excretion on washout accuracy and progression in a model of multiple breath nitrogen washout

BackgroundThe advantages of multiple breath washout tests, and in particular lung clearance index (LCI), over conventional spirometry in cystic fibrosis (CF) are now well established. Although the majority of studies...

Lung Clearance Index as an Outcome Measure for Clinical Trials in Young Children with Cystic Fibrosis. A Pilot Study Using Inhaled Hypertonic Saline

Lung clearance index (LCI), measured by multiple breath washout (MBW), is a noninvasive measure of ventilation inhomogeneity that holds promise as an objective physiologic endpoint for clinical trials in infants and preschool children with cystic fibrosis (CF). To study the feasibility of using LCI to assess treatment effect outcomes in CF trials of infants and preschoolers. The Infant Study of Inhaled Saline trial was a multicenter, randomized, controlled trial of hypertonic (7%) versus isotonic (0.9%) saline inhaled twice daily for 48 weeks in children with CF under 6 years of age. LCI measurements were performed in a single-center pilot substudy at baseline and 48 weeks using a respiratory mass spectrometer and sulfur hexafluoride as the tracer gas. LCI measurements were standardized using published normative data (zLCI) to account for height-related changes in LCI during early childhood. A generalized estimating equation model with an interaction between treatment group and test occasion was used to estimate a treatment effect. A total of 27 participants were randomized; 25 participants, aged (median [range]) 2.6 (0.34-4.95) years, had acceptable baseline and follow-up LCI measures. On average, LCI decreased in the hypertonic saline group (n = 12) by 1.19 z-scores units (95% confidence interval [CI] = -2.46 to 0.06), and remained stable in the isotonic saline group (n = 13) at 0.81 (95% CI = -0.40 to 2.02). A significant treatment effect was observed for zLCI (2.01; 95% CI = 0.26 to 3.76; P = 0.025). MBW testing is feasible in an interventional study in infants and preschool children with CF. These pilot findings support the development of MBW and LCI as an objective outcome measure in interventional trials in young children with CF, and provide estimates for sample size calculations for future studies.

Functional residual capacity (FRC) and lung clearance index (LCI) in mechanically ventilated infants: Application in the newborn with congenital diaphragmatic hernia (CDH)

IntroductionFunctional residual capacity (FRC) and lung clearance index (LCI) are sensitive parameters for early detection of airway disease in infancy. The closed helium dilution method has been applied to assess lung volume and ventilation inhomogeneity (VI) in spontaneously breathing infants. AimsThe aims of this study were as follows: (1) to assess applicability of the helium gas dilution technique in mechanically ventilated infants with high-risk congenital diaphragmatic hernia (CDH) and to evaluate changes in breathing patterns, lung volume, and VI during the first days of life before and after surgery, and (2) to analyze the possible correlation between changes in lung volume, cerebral hemodynamics, and oxygenation before and after surgical correction of CDH through near-infrared spectroscopy (NIRS) monitoring. MethodsLung function tests were performed by multibreath washout traces with an ultrasonic flowmeter and helium gas dilution technique. For all babies, three acceptable FRC and LCI measurements were collected for each test (mean and SD of three measurements were calculated) before surgery (T0), 24h after surgery (T1) during mechanical ventilation, and within 24h after extubation in spontaneous breathing (T2). Cerebral and splanchnic hemodynamics were continuously monitored by NIRS during mechanical ventilation to evaluate relationships between changes in lung volume and capillary–venous oxyhemoglobin saturation in tissues. Fraction of inspired oxygen delivered was adjusted to keep oxygen saturation between 90% and 95%. ResultsThirteen CDH infants were studied; median GA=38weeks (range 35–41) and median BW=3000g (range 1850–3670). FRC and LCI significantly improved after extubation when compared with pre-surgical values. No differences were found in tidal volume (Vt) and NIRS monitoring before and after surgery and after extubation. Neither LCI nor FRC was correlated with NIRS values. ConclusionsHelium gas dilution technique is an applicable and reliable technique to measure lung volumes and ventilation inhomogeneity also in ventilated infants. NIRS is a non-invasive technique to monitor tissue oxygenation during surgery and mechanical ventilation. In CDH newborns these preliminary data show an improvement in both FRC and LCI after extubation.

Practicability of nitrogen multiple‐breath washout measurements in a pediatric cystic fibrosis outpatient setting

Although lung clearance index (LCI) is a sensitive indicator of mild cystic fibrosis (CF) lung disease, it is rarely measured due to lengthy protocols and the commercial unavailability of multiple-breath washout (MBW) setups and tracer gases. We used a newly validated, commercially available nitrogen (N2 ) MBW setup to assess success rate, duration, and variability of LCI within a 20 min timeframe, during clinical routine. We also evaluated the relationship between LCI and other clinical markers of CF lung disease. One hundred thirty six children (83 with CF) between 4 and 16 years were studied in a pediatric CF outpatient setting. One hundred eighteen out of 136 children were naïve to MBW. Within 20 min, each child was trained, N2 MBW was performed, and LCI was analyzed. We assessed intra- and between-test reproducibility in a subgroup of children. At least one LCI was feasible in 123 (90%) children, with a mean (range) of 3.3 (1.2-6.4) min per test. Two or more measurements were feasible in 56 (41%) children. Comparing LCI in CF versus controls, LCI mean (SD) was 12.0 (3.9) versus 6.1 (0.9), and the intra- and inter-test coefficient of repeatability was 1.00 versus 0.81 and 0.96 versus 0.62, respectively. LCI was correlated with spirometry, blood gases, and Pseudomonas aeruginosa infection. Using available N2 MBW equipment, LCI measurements are practical and fast in children. LCI is correlated with markers of CF lung disease. Longer timeframes would be required for triplicate N2 MBW tests in inexperienced children.

Early Cystic Fibrosis Lung Disease Detected by Bronchoalveolar Lavage and Lung Clearance Index

Unrecognized airway infection and inflammation in young children with cystic fibrosis (CF) may lead to irreversible lung disease; therefore early detection and treatment is highly desirable. To determine whether the lung clearance index (LCI) is a sensitive and repeatable noninvasive measure of airway infection and inflammation in newborn-screened children with CF. Forty-seven well children with CF (mean age, 1.55 yr) and 25 healthy children (mean age, 1.26 yr) underwent multiple-breath washout testing. LCI within and between-test variability was assessed. Children with CF also had surveillance bronchoalveolar lavage performed. The mean (SD) LCI in healthy children was 6.45 (0.49). The LCI was higher in children with CF (7.21 [0.81]; P < 0.001). The upper limit of normal for the LCI was 7.41. Fifteen (32%) children with CF had an elevated LCI. LCI measurements were repeatable and reproducible. Airway infection was present in 17 (36%) children with CF, including 7 (15%) with Pseudomonas aeruginosa. Polymicrobial growth was associated with worse inflammation. The LCI was higher in children with Pseudomonas (7.92 [1.16]) than in children without Pseudomonas (7.02 [0.56]) (P = 0.038). The LCI correlated with bronchoalveolar lavage IL-8 (R(2) = 0.20, P = 0.004) and neutrophil count (R(2) = 0.21, P = 0.001). An LCI below the upper limit of normality had a high negative predictive value (93%) in excluding Pseudomonas. The LCI is elevated early in CF, especially in the presence of Pseudomonas and airway inflammation. The LCI is a feasible, repeatable, and sensitive noninvasive marker of lung disease in young children with CF.

Feasibility and Variability of Measuring the Lung Clearance Index in a Multi‐Center Setting

The Lung Clearance Index (LCI) is superior to spirometry in detecting early lung disease in cystic fibrosis (CF) and correlates with structural lung changes seen on CT scans. The LCI has the potential to become a novel outcome parameter for clinical and research purposes. However longitudinal studies are required to further prove its prognostic value. Multi-center design is likely to facilitate realization of such studies. Therefore the aim of the present study was to assess multi-center feasibility and inter-center variability of LCI measurements in healthy children and adolescents. Comparative measurements were performed in unselected patients with CF to confirm previous single-center results. LCI measurements were performed in eight centers using the EasyOne Pro, MBW Module (ndd Medical Technologies, Zurich, Switzerland). The overall success rate for LCI measurements was 75.5%, leaving 102/151 measurements in healthy volunteers and 139/183 measurements in patients with CF for final analysis. Age ranged between 4 and 24 years. Mean LCI (range of means among centers) was 6.3 (6.0-6.5) in healthy volunteers and thus normal. Inter-center variability of center means was 2.9%, ANOVA including Schffé procedure demonstrated no significant inter-center differences (P > 0.05). Mean LCI (range of means among centers) was 8.2 (7.4-8.9) in CF and thus abnormal. Our study demonstrates good multi-center feasibility and low inter-center variability of the LCI in healthy volunteers when measured with the EasyOne Pro MBW module. Our data confirm published LCI data in CF. However, central coordination, quality control, regular training, and supervision during the entire study appear essential for successfully performing multi-center trials.

Relationships between the lung clearance index and conductive and acinar ventilation heterogeneity

The lung clearance index (LCI) derived from a multiple breath washout test has regained considerable popularity in recent years, alternatively being promoted as an early detection tool or a marker of small airways function. In this study, we systematically investigated the link between LCI and indexes of acinar and conductive airways ventilation heterogeneity (Sacin, Scond) to assess potential contributions from both lung zones. Relationships were examined in 55 normal subjects after provocation, where only Scond is known to be markedly increased, and in 55 asthma patients after bronchodilation, in whom both Scond and Sacin ranged between normal and abnormal. LCI was correlated to Scond in both groups (R = 0.37-0.43; P < 0.01 for both); in the asthma group, LCI was also tightly correlated to Sacin (R = 0.70; P < 0.001). Potential mechanisms operational at various levels of the bronchial tree were identified by considering washout curvilinearity in addition to LCI to distinguish specific ventilation and dead space effects (also illustrated by simple 2-compartment model simulations). Although the asthma data clearly demonstrate that LCI can reflect very peripheral ventilation heterogeneities, the normal provocation data also convincingly show that LCI increases may be the exclusive result of far more proximal ventilation heterogeneities. Because LCI potentially includes heterogeneities at all length scales, it is suggested that ventilation imaging in combination with LCI measurement at the mouth could identify the scale of relevant ventilation heterogeneities. In the meantime, interpretations of LCI results in the clinic based on washout curves collected at the mouth should be handled with caution.

Lung clearance index is a sensitive, repeatable and practical measure of airways disease in adults with cystic fibrosis

Background: Lung clearance index (LCI) is a sensitive marker of early lung disease in children but has not been assessed in adults. Measurement is hindered by the complexity of the...

Malaria in neighboring Londoners.

<b>Introduction: </b>We have previously reported increased respiratory symptoms in adult survivors of bronchopulmonary dysplasia (BPD) compared with very low birth weight (VLBW) (&lt;1500g) and term controls. Here we report preliminary findings from spirometric and Lung Clearance Index (LCI) measurements. <b>Objective: </b>To investigate whether adult survivors of BPD have greater impairment of lung function and LCI than age and gender matched VLBW and term controls. <b>Methods: </b>Spirometry measurements (MicroLab ML3500 Mk8™) were obtained in 16 BPD [8male; mean (SD) age 24.9 (3.9) y]<b>,</b> 9 VLBW [Mean (SD) age 25.8 (3.73) y] and 55 term controls [30 male; mean (SD) age 26.0 (4.0) y]. LCI measurements (Innocor™ device) obtained in BPD and VLBW participants were compared to 17 healthy controls [6M, mean (SD) age 30.5 (7.5) y]. <b>Results: </b>For all spirometry end points (FEV₁, FVC, FEV₁/FVC and FEF_25-75), BPD adults had significantly lower values than term controls (p&lt;0.001). Mean FEV₁and FEV₁/FVC measurements were lower in BPD adults than VLBW (p&lt;0.05)). Mean LCI measurements were higher (more impaired) in BPD [mean (SD) 6.99 (0.78)] versus healthy controls [mean (SD) 6.36 (0.362)] (p=0.006). LCI measurements were also higher in BPD than VLBW but this was not statistically significant. Three BPD subjects had entirely normal spirometry but abnormal LCI values (value &gt; healthy control mean +2SD). <b>Conclusions:</b> Our preliminary findings suggest persisting lung function impairment in adult survivors of BPD. LCI may be a useful tool in detecting early small airways disease in adult survivors of preterm birth.