Multimodal longitudinal respiratory function assessment in very low birth weight 7-year-old children

Increasing airway obstruction through life following bronchopulmonary dysplasia: a meta-analysis

Background

Few studies exist investigating lung function trajectories of those born preterm; however growing evidence suggests some individuals experience increasing airway obstruction throughout life. Here we use the studies identified in a recent systematic review to provide the first meta-analysis investigating the impact of preterm birth on airway obstruction measured by the forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) ratio.

Methods

Cohorts were included for analysis if they reported FEV1/FVC in survivors of preterm birth (<37 weeks' gestation) and control populations born at term. Meta-analysis was performed using a random effect model, expressed as standardised mean difference (SMD). Meta-regression was conducted using age and birth year as moderators.

Results

55 cohorts were eligible, 35 of which defined groups with bronchopulmonary dysplasia (BPD). Compared to control populations born at term, lower values of FEV1/FVC were seen in all individuals born preterm (SMD -0.56), with greater differences seen in those with BPD (SMD -0.87) than those without BPD (SMD -0.45). Meta-regression identified age as a significant predictor of FEV1/FVC in those with BPD with the FEV1/FVC ratio moving -0.04 sds away from the term control population for every year of increased age.

Conclusions

Survivors of preterm birth have significantly increased airway obstruction compared to those born at term with larger differences in those with BPD. Increased age is associated with a decline in FEV1/FVC values suggesting increased airway obstruction over the life course.

Use of impulse oscillometry to assess lung function in prematurely born children and young people: Comparisons with spirometry

Premature birth is a risk factor for bronchopulmonary dysplasia (BPD); both of which are associated with obstructive airway disease throughout childhood. Impulse oscillometry (IOS) is an effort-independent, passive measure of tidal breathing, which could have benefits in assessing lung function amongst younger patients unable to perform valid spirometry. A literature search was conducted to investigate the use of IOS in prematurely born children and young people. IOS results correlate with those of spirometry. Reversibility of airway obstruction in children with BPD is variable. IOS could have benefits in assessing individual patient response and suitability for bronchodilator therapy. More work, however, is required to establish multi-ethnic reference ranges and standardise commercially available devices prior to its routine incorporation into clinical practice.

Airwave oscillometry and spirometry in children with asthma or wheeze

OBJECTIVE

Lung function testing is used in diagnosing asthma and assessing asthma control. Spirometry is most commonly used, but younger children can find performing this test challenging. Non-volitional tests such as airwave oscillometry (AOS) may be helpful in that population. We compared the success of spirometry and AOS in assessing bronchodilator responsiveness in children.

METHODS

AOS was conducted alongside routine lung function testing. Resistance at 5 Hz (R5), the difference between the resistance at 5 and 20 Hz (R5-20) and the area under the reactance curve (AX) were assessed. Patients between 5 and 16 years old attending clinic with wheeze or asthma were assessed. Patients performed AOS, followed by spirometry and were then given 400 µg salbutamol; the tests were repeated 15 minutes later.

RESULTS

Lung function testing was performed in 47 children of whom 46 (98%) and 32 (68%) performed acceptable baseline oscillometry and spirometry, respectively (p < 0.001). Children unable to perform acceptable spirometry were younger (7.35, range: 5.4-10.3 years) than those who could (10.4, range: 5.5-16.9 years), p < 0.001. The baseline z-scores of AOS R5 correlated with FEV₁ (r = 0.499, p = 0.004), FEF₇₅ (r = 0.617, p < 0.001), and FEV₁/FVC (r = 0.618, p < 0.001). There was a positive bronchodilator response assessed by spirometry (change in FEV₁ ≥ 12%) in eight children which corresponded to a change in R5 of 36% (range: 30%-50%) and a change in X5 of 39% (range: 15%-54%).

CONCLUSIONS

Oscillometry is a useful adjunct to spirometry in assessing young asthmatic children's lung function. The degree of airway obstruction, however, might affect the comparability of the results of the two techniques.

Geographical Differences and Temporal Improvements in Forced Expiratory Volume in 1 Second of Preterm-Born Children: A Systematic Review and Meta-analysis

Importance

Although preterm birth is associated with later deficits in lung function, there is a paucity of information on geographical differences and whether improvements occur over time, especially after surfactant was introduced.

Objective

To determine deficits in percentage predicted forced expiratory volume in 1 second (%FEV1) in preterm-born study participants, including those with bronchopulmonary dysplasia (BPD) in infancy, when compared with term-born control groups.

Data Sources

Eight databases searched up to December 2021.

Study Selection

Studies reporting spirometry for preterm-born participants with or without a term-born control group were identified.

Data Extraction and Synthesis

Data were extracted and quality assessed by 1 reviewer and checked by another. Data were pooled using random-effects models and analyzed using Review Manager and the R metafor package.

Main Outcomes and Measures

Deficits in %FEV1 between preterm-born and term groups. Associations between deficits in %FEV1 and year of birth, age, introduction of surfactant therapy, and geographical region of birth and residence were also assessed.

Results

From 16 856 titles, 685 full articles were screened: 86 with and without term-born control groups were included. Fifty studies with term controls were combined with the 36 studies from our previous systematic review, including 7094 preterm-born and 17 700 term-born participants. Of these studies, 45 included preterm-born children without BPD, 29 reported on BPD28 (supplemental oxygen dependency at 28 days), 26 reported on BPD36 (supplemental oxygen dependency at 36 weeks' postmenstrual age), and 86 included preterm-born participants. Compared with the term-born group, the group of all preterm-born participants (all preterm) had deficits of %FEV1 of -9.2%; those without BPD had deficits of -5.8%, and those with BPD had deficits of approximately -16% regardless of whether they had BPD28 or BPD36. As year of birth increased, there was a statistically significant narrowing of the difference in mean %FEV1 between the preterm- and term-born groups for the all preterm group and the 3 BPD groups but not for the preterm-born group without BPD. For the all BPD group, when compared with Scandinavia, North America and western Europe had deficits of -5.5% (95% CI, -10.7 to -0.3; P = .04) and -4.1% (95% CI, -8.8 to 0.5; P = .08), respectively.

Conclusions and Relevance

Values for the measure %FEV1 were reduced in preterm-born survivors. There were improvements in %FEV1 over recent years, but geographical region had an association with later %FEV1 for the BPD groups.

Poor early childhood growth is associated with impaired lung function: Evidence from a Ghanaian pregnancy cohort

OBJECTIVES

Nearly 40% of African children under 5 are stunted. We leveraged the Ghana randomized air pollution and health study (GRAPHS) cohort to examine whether poorer growth was associated with worse childhood lung function.

STUDY DESIGN

GRAPHS measured infant weight and length at birth and 3, 6, 9,12 months, and 4 years of age. At age 4 years, n = 567 children performed impulse oscillometry. We employed multivariable linear regression to estimate associations between birth and age 4 years anthropometry and lung function. Next, we employed latent class growth analysis (LCGA) to generate growth trajectories through age 4 years. We employed linear regression to examine associations between growth trajectory assignment and lung function.

RESULTS

Birth weight and age 4 weight-for-age and height-for-age z-scores were inversely associated with airway resistance (e.g., R5 , or total airway resistance: birth weight β = -0.90 cmH2O/L/s, 95% confidence interval [CI]: -1.64, -0.16 per 1 kg increase; and R20 , or large airway resistance: age 4 height-for-age β = -0.40 cmH2O/L/s, 95% CI: -0.57, -0.22 per 1 unit z-score increase). Impaired growth trajectories identified through LCGA were associated with higher airway resistance, even after adjusting for age 4 body mass index. For example, children assigned to a persistently stunted trajectory had higher R5 (β = 2.71 cmH2O/L/s, 95% CI: 1.07, 4.34) and R20 (β = 1.43 cmH2O/L/s, 95% CI: 0.51, 2.36) as compared to normal.

CONCLUSION

Children with poorer anthropometrics through to age 4 years had higher airway resistance in early childhood. These findings have implications for lifelong lung health, including pneumonia risk in childhood and reduced maximally attainable lung function in adulthood.

Pseudorandom Noise Forced Oscillation Technique to Assess Lung Function in Prematurely Born Children

The forced oscillation technique (FOT) is a non-volitional assessment that is used during tidal breathing. A variant of FOT uses a pseudorandom noise (PRN) signal which we postulated might have utility in assessing lung function in prematurely born children. We, therefore, undertook a systematic review to evaluate the evidence regarding PRN FOT. A comprehensive search of the literature was conducted by using the following databases: Medline, Embase, Web of Science and CINAHL. Observational studies, case series/reports and randomized-controlled trials were eligible for inclusion. Article abstracts and full texts were screened independently by two reviewers, with disagreements resolved by discussion or a third reviewer if necessary. Five studies were included (n = 587 preterm children). Three compared PRN FOT with spirometry, and two compare it to the interrupter technique. Most studies failed to report comprehensive methodology of the frequency spectra used to generate the PRN signal. There was evidence that poorer lung function, as assessed by PRN FOT, was associated with a greater burden of respiratory symptoms, but there was insufficient evidence to determine whether PRN FOT performed better than other lung-function tests. Detailed methodological documentation, in accordance with ERS guidance, is needed to assess the benefits of PRN FOT prior to routine clinical incorporation to assess prematurely born children.

Impact of Kangaroo Mother Care Intervention on Immunological and Pulmonary Functions of Preterm Infants during Breastfeeding

Objective

Preterm infants (PTIs) are prone to respiratory failure or other diseases due to immature organ development and poor immunological function. Herein, the effects of Kangaroo Mother Care (KMC) on the immunological and pulmonary functions of PTIs during breastfeeding were investigated in this study.

Methods

The study recruited 86 delivery women and their PTIs with preterm pregnancy outcomes, consisting of 46 cases receiving breastfeeding plus KMC intervention (KMC group) and 40 cases receiving breastfeeding plus routine care (control group). The time of first lactation, time of first breastfeeding, and duration of first breastfeeding were observed in both cohorts. The breastfeeding status was assessed using the LATCH system. Maternal psychological status was evaluated by the breastfeeding self-efficacy scale (BSES) and self-rating anxiety/depression scale (SAS/SDS). The growth and development of PTIs were recorded, and the levels of postalbumin (PA), transferrin (TRF), plasma albumin (ALB), immunoglobulin (Ig) A, IgG, IgM, and complement C3 and C4 were measured. The tidal volume (VT), tidal volume per kilogram (VT/kg), minute volume (MV), and minute volume per kilogram (MV/kg) were detected using a pulmonary function tester.

Results

The KMC group presented shorter time of first lactation and first breastfeeding than the control group, with longer duration of first breastfeeding (P < 0.05). After intervention, the BSES scores of delivery women were increased, while the SAS and SDS scores were decreased, with more notable improvements in the KMC group (P < 0.05). The levels of PA, TRF, ALB, IgA, IgG, VT, and MV were elevated in PTIs in both groups, with more evident increase in the KMC group than in the control group (P < 0.05). A better growth of PTIs was found in the KMC group than the control group (P < 0.05).

Conclusions

The study demonstrated that KMC intervention during breastfeeding could benefit PTIs specifically regarding their immunological and pulmonary functions.