Survey of clinical infant lung function testing practices

Beyond the Skin: Reduced Lung Function Associated With Atopic Dermatitis in Infants

BACKGROUND

Very few studies have examined lung function parameters using tidal breath analysis (TBA) in atopic dermatitis (AD) with its high potential for progression to asthma.

OBJECTIVE

To measure lung functions using TBA in infants with AD and in healthy controls (HCs), and to investigate the effects of disease severity, food sensitivity, and history of recurrent wheezing on TBA parameters in infants with AD.

METHODS

Two hundred thirty infants were included in this prospective cross-sectional study, including an AD group (n = 150) and an HC group (n = 80). Food sensitivity was assessed by means of food-specific IgE or the skin prick test. The severity of the disease was evaluated using the SCORing Atopic Dermatitis. Lung function was assessed using TBA.

RESULTS

The following TBA parameters were significantly lower in the AD group than in the HC group (P < .05): time to peak tidal expiratory flow, exhaled volume to peak tidal expiratory flow, ratio of time to peak tidal expiratory flow to expiratory time, ratio of exhaled volume to peak tidal expiratory flow to total expiratory volume, expiratory flow when 25% of tidal volume remains in the lungs, respiratory rate, and minute ventilation. No difference was observed in the AD group when TBA parameters were compared according to disease severity, food sensitivity, and history of recurrent wheezing (P > .05). The receiver-operating characteristic curve demonstrated by the ratio of time to peak tidal expiratory flow to expiratory time yielded an area under the curve of 0.826 (CI, 0.772-0.879), with a cutoff value of 31.65 or higher in differentiating AD, with a sensitivity of 78.7% and a specificity of 77.5%.

CONCLUSIONS

TBA curves can be a useful tool for demonstrating expiratory airway obstruction in AD and for providing objective information for the clinician. Bronchial obstruction was detected in young children with AD irrespective of the severity of the disease, food sensitivity, and history of recurrent wheezing.

Wheeze Recognition Algorithm for Remote Medical Care Device in Children: Validation Study

BACKGROUND

Since 2020, peoples' lifestyles have been largely changed due to the COVID-19 pandemic worldwide. In the medical field, although many patients prefer remote medical care, this prevents the physician from examining the patient directly; thus, it is important for patients to accurately convey their condition to the physician. Accordingly, remote medical care should be implemented and adaptable home medical devices are required. However, only a few highly accurate home medical devices are available for automatic wheeze detection as an exacerbation sign.

OBJECTIVE

We developed a new handy home medical device with an automatic wheeze recognition algorithm, which is available for clinical use in noisy environments such as a pediatric consultation room or at home. Moreover, the examination time is only 30 seconds, since young children cannot endure a long examination time without crying or moving. The aim of this study was to validate the developed automatic wheeze recognition algorithm as a clinical medical device in children at different institutions.

METHODS

A total of 374 children aged 4-107 months in pediatric consultation rooms of 10 institutions were enrolled in this study. All participants aged ≥6 years were diagnosed with bronchial asthma and patients ≤5 years had reported at least three episodes of wheezes. Wheezes were detected by auscultation with a stethoscope and recorded for 30 seconds using the wheeze recognition algorithm device (HWZ-1000T) developed based on wheeze characteristics following the Computerized Respiratory Sound Analysis guideline, where the dominant frequency and duration of a wheeze were >100 Hz and >100 ms, respectively. Files containing recorded lung sounds were assessed by each specialist physician and divided into two groups: 177 designated as "wheeze" files and 197 as "no-wheeze" files. Wheeze recognitions were compared between specialist physicians who recorded lung sounds and those recorded using the wheeze recognition algorithm. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value for all recorded sound files, and evaluated the influence of age and sex on the wheeze detection sensitivity.

RESULTS

Detection of wheezes was not influenced by age and sex. In all files, wheezes were differentiated from noise using the wheeze recognition algorithm. The sensitivity, specificity, positive predictive value, and negative predictive value of the wheeze recognition algorithm were 96.6%, 98.5%, 98.3%, and 97.0%, respectively. Wheezes were automatically detected, and heartbeat sounds, voices, and crying were automatically identified as no-wheeze sounds by the wheeze recognition algorithm.

CONCLUSIONS

The wheeze recognition algorithm was verified to identify wheezing with high accuracy; therefore, it might be useful in the practical implementation of asthma management at home. Only a few home medical devices are available for automatic wheeze detection. The wheeze recognition algorithm was verified to identify wheezing with high accuracy and will be useful for wheezing management at home and in remote medical care.

Tidal breath in healthy term newborns: An analysis from the 2nd to the 30th days of life

BACKGROUND

Few data are available concerning normative lung function parameters measured in unsedated neonates.

AIM

To evaluate lung function changes in neonates.

METHODS

In this prospective cohort study, tidal breath parameters were measured using the MasterScreen PAED system and standardized protocols. Measurements were performed on 60 (30 male) term, healthy, unsedated neonates on the postnatal 2nd and 30th days.

RESULTS

Expiratory time (TE; p < .001; Cohen's d = 0.561), exhaled volume to peak tidal expiratory flow (VPTEF; p < .001; Cohen's d = 0.789), minute ventilation (p < .001; Cohen's d = 0.926), tidal volume (VT; p < .001; Cohen's d = 1.835), expiratory flow when 75%, 50%, and 25% of tidal volume remaining in the lungs (TEF75 [p < .001; Cohen's d = 1.070], TEF50 [p < .001; Cohen's d = 0.824], TEF25 [p < .001; Cohen's d = 0.568]), and inspiratory time (Ti; p < .001; Cohen's d = 0.654) were higher on Day 30 compared to Day 2, while time to reach peak tidal expiratory flow to total expiratory time (TPTEF/TE; p = .006; Cohen's d = 0.371), the volume until peak tidal expiratory flow to total expiratory volume (VPTEF/VE; p = .001; Cohen's d = 0.447), and respiration rate (RR; p = .001; Cohen's d = 0.432) were lower, and Ti/TE was unchanged. Positive correlation was observed between length and VT (r = .347; p = .008) on Day 2 and (r = .338; p = .008) on Day 30.

CONCLUSIONS

The present study reveals the physiological changes occurring in lung functions in healthy term neonates during the neonatal period.

A wheeze recognition algorithm for practical implementation in children

BACKGROUND

The detection of wheezes as an exacerbation sign is important in certain respiratory diseases. However, few highly accurate clinical methods are available for automatic detection of wheezes in children. This study aimed to develop a wheeze detection algorithm for practical implementation in children.

METHODS

A wheeze recognition algorithm was developed based on wheezes features following the Computerized Respiratory Sound Analysis guidelines. Wheezes can be detected by auscultation with a stethoscope and using an automatic computerized lung sound analysis. Lung sounds were recorded for 30 s in 214 children aged 2 months to 12 years and 11 months in a pediatric consultation room. Files containing recorded lung sounds were assessed by two specialist physicians and divided into two groups: 65 were designated as "wheeze" files, and 149 were designated as "no-wheeze" files. All lung sound judgments were agreed between two specialist physicians. We compared wheeze recognition between the specialist physicians and using the wheeze recognition algorithm and calculated the sensitivity, specificity, positive predictive value, and negative predictive value for all recorded sound files to evaluate the influence of age on the wheeze detection sensitivity.

RESULTS

The detection of wheezes was not influenced by age. In all files, wheezes were differentiated from noise using the wheeze recognition algorithm. The sensitivity, specificity, positive predictive value, and negative predictive value of the wheeze recognition algorithm were 100%, 95.7%, 90.3%, and 100%, respectively.

CONCLUSIONS

The wheeze recognition algorithm could identify wheezes in sound files and therefore may be useful in the practical implementation of respiratory illness management at home using properly developed devices.

Early Neonatal Oxygen Exposure Predicts Pulmonary Morbidity and Functional Deficits at 1 Year

OBJECTIVE

To evaluate the predictive value of cumulative oxygen exposure thresholds over the first 2 postnatal weeks, linking them to bronchopulmonary dysplasia (BPD) and 1-year pulmonary morbidity and lung function in extremely low gestational age newborns.

STUDY DESIGN

Infants (N = 704) enrolled in the Prematurity and Respiratory Outcomes Program, a multicenter prospective cohort study, that survived to discharge were followed through their neonatal intensive care unit hospitalization to 1-year corrected age. Cumulative oxygen exposure (Oxygen_AUC14) thresholds were derived from univariate models of BPD, stratifying infants into high-, intermediate-, and low-oxygen exposure groups. These groups were then used in multivariate logistic regressions to prospectively predict post-prematurity respiratory disease (PRD), respiratory morbidity score (RMS) in the entire cohort, and pulmonary function z scores (N = 108 subset of infants) at 1-year corrected age.

RESULTS

Over the first 14 postnatal days, infants exposed to high oxygen averaged ≥33.1% oxygen, infants exposed to intermediate oxygen averaged 29.1%-33.1%, and infants exposed to low oxygen were below both cutoffs. In multivariate models, infants exposed to high oxygen showed increased PRD and RMS, whereas infants exposed to intermediate oxygen demonstrated increased moderate/severe RMS. Infants in the high/intermediate groups had decreased forced expiratory volume at 0.5 seconds/forced vital capacity ratio.

CONCLUSIONS

Oxygen_AUC14 establishes 3 thresholds of oxygen exposure that risk stratify infants early in their neonatal course, thereby predicting short-term (BPD) and 1-year (PRD, RMS) respiratory morbidity. Infants with greater Oxygen_AUC14 have altered pulmonary function tests at 1 year of age, indicating early evidence of obstructive lung disease and flow limitation, which may predispose extremely low gestational age newborns to increased long-term pulmonary morbidity.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01435187.

Hemoglobin Levels Pre- and Posttreatment as a Surrogate for Disease Severity in Early-Onset Scoliosis

STUDY DESIGN

Prospective cohort.

OBJECTIVE

To compare preoperative hemoglobin levels to postoperative hemoglobin levels in patients with early-onset scoliosis (EOS).

SUMMARY OF BACKGROUND DATA

Elevated hemoglobin (Hgb) may be a marker for preoperative hypoxia in patients with EOS and thoracic insufficiency syndrome (TIS). The changes in Hgb level after treatment may be a surrogate marker for improved oxygenation.

METHODS

Because normal levels of Hgb vary with patient age, Hgb z scores were calculated by dividing age-adjusted mean Hgb levels by the age-adjusted standard deviation. Elevated Hgb was defined by a hemoglobin z score >1. Patients with a baseline Hgb value measured before initial implantation with at least one follow-up measurement, at 6, 12, or 18 months, were included in longitudinal analysis. Change in Hgb z score as well as change in curve magnitude over time was assessed using piecewise linear mixed modeling for patients with elevated Hgb and those without.

RESULTS

Two hundred sixty-seven patients with EOS were treated surgically over the study period. Average age at initial implantation was 6.8 years. Forty-eight (18%; 95% confidence interval = 13.7%, 23.2%) subjects had an elevated Hgb (z score > 1) level before implantation procedure. Hgb levels decreased in subjects with elevated Hgb from implantation to 6 months (p < .001) with no change in Hgb from 6 to 12 months (p = .46) or from 12 to 18 months (p = .59), but an overall decrease from preoperative to 18 months (p < .001). There was no change in Hgb levels for subjects without elevated Hgb from implantation to 6 months (p = .94), from 6 to 12 months (p = .61), or from 12 to 18 months (p = .78).

CONCLUSIONS

In some patients with EOS and TIS, there appears to be significant positive impact on oxygenation from distraction instrumentation as evidenced by a meaningful proxy measurement: improvement in abnormal preoperative Hgb levels after surgery.

LEVEL OF EVIDENCE

III.

Pulmonary Function Testing in Pediatric Pneumonia Patients With Wheezing Younger Than 3 Years of Age

Background. Wheezing symptoms are one of the risk factors in young pneumonia patients that often leads to asthma development. Infant pulmonary function test (iPFT) is potentially a useful tool to help identify and manage these high-risk pneumonia patients. Methods. To examine whether patients with wheezing symptoms are more likely to have poorer pulmonary function and treatment outcomes, and also to explore the clinical benefit of iPFT in young pneumonia patients, we conducted a retrospective analysis of 1005 pneumonia inpatients <3 years of age who had undergone iPFT testing in 2016 at Liuzhou Maternity and Child Healthcare Hospital in Guang-Xi, China. Results. We identified from the hospital database 505 pneumonia patients who presented with wheezing and 500 without wheezing. Univariate analysis showed that wheezing symptoms, viral infection, age <1 year, female gender, and prematurity were significantly associated with poorer iPFT results. After adjusting for confounders, patients with wheezing showed significantly poorer pulmonary function. Patients with wheezing had longer length of stay (7.9 ± 3.9 days vs 6.5 ± 2.6 days; P < .001) and lower percent with no residual clinical symptoms at discharge (58% vs 98%; P < .001) when compared with those of non-wheezing patients. In addition, 81% of patients with viral infection as compared with 43% of patients with nonviral infection presented with wheezing symptoms (P < .001). Conclusion. Wheezing symptoms were associated with poorer iPFT measures and treatment outcomes for pneumonia inpatients <3 years of age. Patients with wheezing had poorer treatment outcomes. iPFT can be useful in assessing and monitoring young patients with high risk of developing asthma or chronic lung disease later in life.

Reference equations for the interpretation of forced expiratory and plethysmographic measurements in infants

BACKGROUND

Pulmonary function testing is commonly performed for diagnosis and clinical management of respiratory diseases. It is important to use appropriate reference equations from healthy subjects for interpretation of data from infants with lung disease. This study aimed to determine if published reference equations were similar to forced flow measures and plethysmographic infant pulmonary function testing data collected in the Canadian Healthy Infant Longitudinal Development (CHILD) Study.

METHODS

Reference equations for five pulmonary function variables (FEV_0.5 , FVC, FEF_25-75 , FEV_0.5 /FVC ratio and plethysmography (FRC_pleth )) were developed using data from the nSpire system. New reference equations developed using healthy data from the CHILD Study were compared to previously published reference equations for forced flow and plethysmographic measures.

RESULTS

The current analysis included 131 infants (on 181 test occasions) with forced flow measures and 161 infants (on 246 test occasions) with plethysmography measures, aged 3-24 months. Age and length were major determinants of both forced flow and plethysmography measures. In addition, ethnicity (Caucasian vs non-Caucasian) was significantly associated with FEV_0.5 /FVC and FEF_25-75 measures. We found that the published reference equations based on custom-built equipment or commercially available systems provided poor fit to our current pulmonary function testing data, resulting in placing a large proportion of our healthy population outside the normal ranges.

CONCLUSIONS

Our current data support the need for population and device specific reference data for infant pulmonary function studies. By deriving new equipment-specific reference equations for our healthy population, we provide normative data to other centers utilizing this equipment.

Efficacy and safety of chloral hydrate sedation in infants for pulmonary function tests

Objective:

To describe the efficacy and safety of chloral hydrate sedation in infants for pulmonary function tests.

Methods:

All sedation attempts for pulmonary function tests in infants carried out between June 2007 and August 2014 were evaluated. Obstructive sleep apnea and heart disease were contraindications to the exams. Anthropometric data, exam indication, used dose, outcomes of sedation and clinical events were recorded and described.

Results:

The sedation attempts in 277 infants (165 boys) with a median age of 51.5 weeks of life (14-182 weeks) were evaluated. The main indication for the tests was recurrent wheezing (56%) and the chloral hydrate dose ranged from 50 to 80mg/kg (orally). Eighteen (6.5%) infants had some type of clinical complication, with the most frequent being cough and/or airway secretion (1.8%); respiratory distress (1.4%) and vomiting (1.1%). A preterm infant had bradycardia for approximately 15 minutes, which was responsive to tactile stimulation. All observed adverse effects were transient and there was no need for resuscitation or use of injectable medications.

Conclusions:

The data demonstrated that chloral hydrate at the employed doses is a safe and effective medicament for sedation during short procedures in infants, such as pulmonary function tests. Because of the possibility of severe adverse events, recommendations on doses and contraindications should be strictly followed and infants should be monitored by trained staff.

Efficacy and safety of chloral hydrate sedation in infants for pulmonary function tests

OBJECTIVE

To describe the efficacy and safety of chloral hydrate sedation in infants for pulmonary function tests.

METHODS

All sedation attempts for pulmonary function tests in infants carried out between June 2007 and August 2014 were evaluated. Obstructive sleep apnea and heart disease were contraindications to the exams. Anthropometric data, exam indication, used dose, outcomes of sedation and clinical events were recorded and described.

RESULTS

The sedation attempts in 277 infants (165 boys) with a median age of 51.5 weeks of life (14 to 182 weeks) were evaluated. The main indication for the tests was recurrent wheezing (56%) and the chloral hydrate dose ranged from 50 to 80mg/kg (orally). Eighteen (6.5%) infants had some type of clinical complication, with the most frequent being cough and/or airway secretion (1.8%); respiratory distress (1.4%) and vomiting (1.1%). A preterm infant had bradycardia for approximately 15 minutes, which was responsive to tactile stimulation. All observed adverse effects were transient and there was no need for resuscitation or use of injectable medications.

CONCLUSIONS

The data demonstrated that chloral hydrate at the employed doses is a safe and effective medicament for sedation during short procedures in infants, such as pulmonary function tests. Because of the possibility of severe adverse events, recommendations on doses and contraindications should be strictly followed and infants should be monitored by trained staff.

Multiple breath washout cannot be used for tidal breath parameter analysis in infants

BACKGROUND

Multiple breath washout (MBW) testing with SF6 gas mixture is routinely used to assess ventilation distribution in infants. It is currently unknown whether SF6 changes tidal breathing parameters during MBW in infants. We investigated if SF6 does change tidal breathing parameters in infants and whether a separate tidal breathing trace prior to MBW testing is necessary.

METHODS

Tidal breathing during MBW was compared to standard tidal breathing in room air in healthy infants (n = 38), preterm infants (n = 41), and infants with cystic fibrosis (n = 41). Outcomes included inspiratory and expiratory times (TI and TE ), time to peak tidal inspiratory and expiratory flow (tPTIF and tPTEF), tidal volume (VT ), respiratory rate (f), and minute ventilation (VE ).

RESULTS

Breath times were all significantly increased for both healthy (TE : -0.0790 [-0.10566, -0.05217]; mean difference [95% confidence intervals]) and CF (-0.109 [-0.15235, -0.06607]) infants during the MBW wash-in (P < 0.001). Healthy infants and those with CF showed decreased f during MBW wash-in (P < 0.001); however, no change in VT, resulting in a decreased VE (0.154 (0.086, 0.222) and 0.128 (0.069, 0.186) for healthy and CF infants, respectively, P < 0.001). Preterm infants experienced a decreased VE during both wash-in (0.134 [0.061, 0.207]; P < 0.001) and wash-out phases of MBW (P < 0.05).

CONCLUSION

There are differences in tidal breathing parameters during MBW testing with SF6 in infants. It is, therefore, important to measure a separate tidal breathing trace in room air, prior to MBW testing to ensure rigour of tidal breath indices derived from analysis.

Key paediatric messages from Amsterdam

The Paediatric Assembly of the European Respiratory Society (ERS) maintained its high profile at the 2015 ERS International Congress in Amsterdam. There were symposia on preschool wheeze, respiratory sounds and cystic fibrosis; an educational skills workshop on paediatric respiratory resuscitation; a hot topic session on risk factors and early origins of respiratory diseases; a meet the expert session on paediatric lung function test reference values; and the annual paediatric grand round. In this report the Chairs of the Paediatric Assembly's Groups highlight the key messages from the abstracts presented at the Congress.

Pediatric pulmonology year in review 2014: Part 2

To better meet the needs of our readership for updated perspectives on the rapidly expanding knowledge in our field, we here summarize the past year's publications in our major topic areas, as well as selected publications in these areas from the core clinical journal literature outside our own pages. This is Part 2 of a series and covers articles on neonatal lung disease, pulmonary physiology, and respiratory infection.

Progressive ventilation inhomogeneity in infants with cystic fibrosis after pulmonary infection

Measures of ventilation distribution are promising for monitoring early lung disease in cystic fibrosis (CF). This study describes the cross-sectional and longitudinal impacts of pulmonary inflammation and infection on ventilation homogeneity in infants with CF.Infants diagnosed with CF underwent multiple breath washout (MBW) testing and bronchoalveolar lavage at three time points during the first 2 years of life.Measures were obtained for 108 infants on 156 occasions. Infants with a significant pulmonary infection at the time of MBW showed increases in lung clearance index (LCI) of 0.400 units (95% CI 0.150-0.648; p=0.002). The impact was long lasting, with previous pulmonary infection leading to increased ventilation inhomogeneity over time compared to those who remained free of infection (p<0.05). Infection with Haemophilus influenzae was particularly detrimental to the longitudinal lung function in young children with CF where LCI was increased by 1.069 units for each year of life (95% CI 0.484-1.612; p<0.001).Pulmonary infection during the first year of life is detrimental to later lung function. Therefore, strategies aimed at prevention, surveillance and eradication of pulmonary pathogens are paramount to preserve lung function in infants with CF.

Lung function in African infants: a pilot study

BACKGROUND

The burden of childhood respiratory illness is large in low and middle income countries (LMICs). Infant lung function (ILF) testing may provide useful information about lung growth and susceptibility to respiratory disease. However, ILF has not been widely available in LMICs settings where the greatest burden of childhood respiratory disease occurs.

AIM

To implement and evaluate a pilot study of ILF testing in a semi-rural setting in South Africa.

METHOD

Infant lung function testing was established at a community hospital in South Africa. All measures were done in unsedated infants during sleep. Measurements, made with the infant quietly breathing through a face mask and bacterial filter, included tidal breathing (TBFVL), exhaled nitric oxide (eNO), and sulphur hexafluoride multiple breath washout (MBW) measures using an ultrasonic flow meter and chemoluminescent NO analyzer.

RESULTS

Twenty infants, mean age of 7.7 (SD 2.9) weeks were tested; 8 (40%) were Black African and 12 (60%) were mixed race. Five (25%) infants were preterm. There were 19 (95%) successful TBFVL and NO tests and 18 (90%) successful MBW tests. The mean tidal volume was 30.5 ml (SD 5.9), respiratory rate 50.2 breaths per minute (SD 8.7), and eNO 10.4 ppb (SD 7.3). The mean MBW measures were: functional residual capacity 71 ml (SD 13) and the lung clearance index 7.6 (SD 0.5). The intra-subject coefficient of variations (CV) of lung function measures were similar to published normative data for Caucasian European infants.

CONCLUSION

In this study we demonstrate that unsedated infant lung function measures of tidal breathing, MBW, and eNO are feasible in a semi-rural African setting with rates comparable to those reported from high income countries.

Validation of computerized wheeze detection in young infants during the first months of life

BACKGROUND

Several respiratory diseases are associated with specific respiratory sounds. In contrast to auscultation, computerized lung sound analysis is objective and can be performed continuously over an extended period. Moreover, audio recordings can be stored. Computerized lung sounds have rarely been assessed in neonates during the first year of life. This study was designed to determine and validate optimal cut-off values for computerized wheeze detection, based on the assessment by trained clinicians of stored records of lung sounds, in infants aged <1 year.

METHODS

Lung sounds in 120 sleeping infants, of median (interquartile range) postmenstrual age of 51 (44.5-67.5) weeks, were recorded on 144 test occasions by an automatic wheeze detection device (PulmoTrack®). The records were retrospectively evaluated by three trained clinicians blinded to the results. Optimal cut-off values for the automatically determined relative durations of inspiratory and expiratory wheezing were determined by receiver operating curve analysis, and sensitivity and specificity were calculated.

RESULTS

The optimal cut-off values for the automatically detected durations of inspiratory and expiratory wheezing were 2% and 3%, respectively. These cutoffs had a sensitivity and specificity of 85.7% and 80.7%, respectively, for inspiratory wheezing and 84.6% and 82.5%, respectively, for expiratory wheezing. Inter-observer reliability among the experts was moderate, with a Fleiss' Kappa (95% confidence interval) of 0.59 (0.57-0.62) for inspiratory and 0.54 (0.52 - 0.57) for expiratory wheezing.

CONCLUSION

Computerized wheeze detection is feasible during the first year of life. This method is more objective and can be more readily standardized than subjective auscultation, providing quantitative and noninvasive information about the extent of wheezing.

Is there a relationship between thoracic dimensions and pulmonary function in early-onset scoliosis?

STUDY DESIGN

Cross-sectional retrospective analysis.

OBJECTIVE

To examine the degree of correlation between thoracic dimension outcome measures and pulmonary function in early-onset scoliosis (EOS).

SUMMARY OF BACKGROUND DATA

Change in thoracic dimension (TD) measurements and spine length are commonly reported outcome measures after treatment for EOS. Although ultimately improving or maintaining pulmonary function is the goal of EOS treatment strategies, it is unclear whether commonly reported 2-dimensional TD measurements represent good predictors of pulmonary function.

METHODS

A cross-sectional analysis of patients including all diagnoses obtained from 2 EOS databases containing TD measurements and pulmonary function data was performed. Relationships between individual TD measurements and pulmonary function measurements were assessed using the Pearson correlation analysis. TD measurements (pelvic inlet width, T1-T12 height, T1-S1 height, and coronal chest width) and standard pulmonary function measurements were compared. TD percentiles normalized for pelvic inlet width were also calculated and correlated with pulmonary function measurement percentiles. Univariate and multivariate linear regression analyses determined whether TD measurements could predict pulmonary function.

RESULTS

There were 121 patients (65 females, 56 males) in the study. Mean age at evaluation was 9.3 years (range, 2.7-18.1 yr). T1-T12 height, T1-S1 height, maximal chest width, and pelvic inlet width were all significantly correlated with forced air volume expelled in 1 second, total forced air volume, and total lung capacity (correlation coefficients [r] 0.33-0.61; all P<0.001). T1-T12 predicted percentile (normalized for pelvic width) was significantly correlated with forced air volume expelled in 1 second and total forced air volume predicted percentiles (r=0.32, P<0.001 and r=0.27, P=0.004, respectively). Regression analysis determined that T1-T12 percentile was a significant predictor of forced air volume expelled in 1 second percentile and total forced air volume percentiles. Regression analysis found no predictive factors of total lung capacity percentile.

CONCLUSION

Traditional 2-dimensional TD measurements (T1-T12 height) used to measure outcomes in EOS can be used as weak predictors of pulmonary function outcome. However, better outcome measures need to be developed, such as 3-dimensional and dynamic measurements.

LEVEL OF EVIDENCE

3.

Evolution of lung function during the first year of life in newborn screened cystic fibrosis infants

Rationale

Newborn screening (NBS) for cystic fibrosis (CF) allows early intervention. Design of randomised controlled trials (RCT) is currently impeded by uncertainty regarding evolution of lung function, an important trial end point in such infants.

Objective

To assess changes in pulmonary function during the first year of life in CF NBS infants.

Methods

Observational longitudinal study. CF NBS infants and healthy controls were recruited between 2009 and 2011. Lung Clearance Index (LCI), plethysmographic lung volume (plethysmographic functional residual capacity (FRC_pleth)) and forced expired volume (FEV_0.5) were measured at 3 months and 1 year of age.

Main results

Paired measurements were obtained from 72 CF infants and 44 controls. At 3 months, CF infants had significantly worse lung function for all tests. FEV_0.5 improved significantly (0.59 (95% CI 0.18 to 0.99) z-scores; p<0.01) in CF infants between 3 months and 1 year, and by 1 year, FEV_0.5 was only 0.52 (0.89 to 0.15) z-scores less than in controls. LCI and FRC_pleth remained stable throughout the first year of life, being on average 0.8 z-scores higher in infants with CF. Pulmonary function at 1 year was predicted by that at 3 months. Among the 45 CF infants with entirely normal LCI and FEV_0.5 at 3 months, 80% remained so at 1 year, while 74% of those with early abnormalities remained abnormal at 1 year.

Conclusions

This is the first study reporting improvements in FEV_0.5 over time in stable NBS CF infants treated with standard therapy. Milder changes in lung function occurred by 1 year than previously reported. Lung function at 3 months predicts a high-risk group, who should be considered for intensification of treatment and enrolment into RCTs.