Longitudinal Evaluation of Pulmonary Function in Premature Infants

Background: Infants born premature have decreased pulmonary function compared to full-term infants. Longitudinal infant studies are needed to determine whether impaired pulmonary function following premature birth demonstrates catch-up growth. This study measured airway and parenchymal function in infants born premature at approximately 6 months and 1 year of age to assess growth and the effects of gestational age (GA) and sex. Methods: 37 infants born premature participated in two study visits (V1 and V2) at Riley Hospital in Indianapolis, IN. While sleeping, forced expiratory maneuvers were preformed to measure airway function. DLCO, diffusion capacity of the lung, and VA, alveolar volume, were measured under conditions of room air. Z scores were calculated to compare infants born premature and full-term, adjusting for size, race, and sex. Demographics: The subjects consisted of 21 females and 16 males. There were 7 subjects born at 24 – 28 weeks, 6 at 29 – 31 weeks, and 24 at 32 – 36 weeks. Pulmonary Testing Results: Variable Z Score V1 V2 V2-V1 Male Female GA DLCO -0.17 (-0.59, 0.26) *-0.75 (-1.18, -0.31) *-0.58 (-1.03, -0.12) *-0.86 (-1.42, -0.30) -0.05 (-0.53, 0.43) *0.13 (0.001,0.28) VA 0.06 (-0.24, 0.45) -0.24 (-0.70, 0.23) -0.30 (-0.72 ,0.14) -0.14 (-0.71, 0.43) -0.04 (-0.53, 0.45) 0.09 (-0.05, 0.23) FVC *-0.38 (-0.60, -0.17) **-1.05 (-1.36, -0.74) **-0.67 (-0.98, -0.36) **-0.71 (-1.04, -0.38) **-0.72 (-1.01, -0.44) 0.07 (-0.01, 0.15) FEF50 **-0.88 (-1.15, -0.62) **-1.36 (-1.63, -1.08) *-0.47 (-0.80, -0.14) **-1.12 (-1.44, -0.79) **-1.12 (-1.40, -0.84) **0.15 (0.07,0.23) FEF75 **-0.57 (-0.88, -0.26) **-1.16 (-1.48, -0.83) *-0.59 (-0.93, -0.24) **-0.76 (-1.16, -0.35) **-0.97 (-1.32, -0.62) **0.21 (0.11,0.31) * = p < 0.05 ** = p < 0.001 DLCO was decreased in male subjects compared to female subjects and male full-term infants. VA was not significantly different between subjects and full-term infants. Compared to full-term infants, subjects had decreased forced vital capacity (FVC) and forced expiratory flow at 50% and 75% vital capacity (FEF50 and FEF75). DLCO, FVC, FEF50, and FEF75 exhibited a significant decrease in pulmonary function from V1 to V2 among subjects. Gestational age showed a positive relationship for DLCO, FEF50, and FEF75. Conclusion and Potential Impact: The subjects did not exhibit catch-up growth, or an increase in z score from V1 to V2, in parenchymal and airway function for DLCO, FVC, FEF50, and FEF75. Gestational age and sex were factors affecting pulmonary function. As premature infants are born with lower pulmonary function than full-term infants, it is important to understand how lungs continue to develop after release from the NICU.

Effects of Endurance Training Intensity on Pulmonary Diffusing Capacity at Rest and after Maximal Aerobic Exercise in Young Athletes

This study compared the effects of varying aerobic training programs on pulmonary diffusing capacity (TLCO), pulmonary diffusing capacity for nitric oxide (TLNO), lung capillary blood volume (Vc) and alveolar–capillary membrane diffusing capacity (DM) of gases at rest and just after maximal exercise in young athletes. Sixteen healthy young runners (16–18 years) were randomly assigned to an intense endurance training program (IET, n = 8) or to a moderate endurance training program (MET, n = 8). The training volume was similar in IET and MET but with different work intensities, and each lasted for 8 weeks. Participants performed a maximal graded cycle bicycle ergometer test to measure maximal oxygen consumption (VO2max) and maximal aerobic power (MAP) before and after the training programs. Moreover, TLCO, TLNO and Vc were measured during a single breath maneuver. After eight weeks of training, all pulmonary parameters with the exception of alveolar volume (VA) and inspiratory volume (VI) (0.104 < p < 0889; 0.001 < ES < 0.091), measured at rest and at the end of maximal exercise, showed significant group × time interactions (p < 0.05, 0.2 < ES < 4.0). Post hoc analyses revealed significant pre-to-post decreases for maximal heart rates (p < 0.0001, ES = 3.1) and improvements for VO2max (p = 0.006, ES = 2.22) in the IET group. Moreover, post hoc analyses revealed significant pre-to-post improvements in the IET for DM, TLNO, TLCO and Vc (0.001 < p < 0.0022; 2.68 < ES < 6.45). In addition, there were increases in Vc at rest, VO2max, TLNO and DM in the IET but not in the MET participants after eight weeks of training with varying exercise intensities. Our findings suggest that the intensity of training may represent the most important factor in increasing pulmonary vascular function in young athletes.

The Effect of an Olympic Distance Triathlon on Pulmonary Diffusing Capacity and its Recovery 24 Hours Later

The Olympic distance triathlon includes maximal exercise bouts with transitions between the activities. This study investigated the effect of an Olympic distance triathlon (1.5-km swim, 40-km bike, 10-km run) on pulmonary diffusion capacity (DLCO). In nine male triathletes (age: 24 ± 4.7 years), we measured DLCO and calculated the DLCO to alveolar volume ratio (DLCO/VA) and performed spirometry testing before a triathlon (pre-T), 2 hours after the race (post-T), and the day following the race (post-T-24 h). DLCO was measured using the 9-s breath-holding method. We found that (1) DLCO decreased significantly between pre- and post-T values (38.52 ± 5.44 vs. 35.92 ± 6.63 ml∙min-1∙mmHg-1) (p < 0.01) and returned to baseline at post-T-24 h (38.52 ± 5.44 vs. 37.24 ± 6.76 ml∙min-1∙mmHg-1, p > 0.05); (2) DLCO/VA was similar at the pre-, post- and post-T-24 h DLCO comparisons; and (3) forced expiratory volume in the first second (FEV1) and mean forced expiratory flow during the middle half of vital capacity (FEF25-75%) significantly decreased between pre- and post-T and between pre- and post-T-24-h (p < 0.02). In conclusion, a significant reduction in DLCO and DLCO/VA 2 hours after the triathlon suggests the presence of pulmonary interstitial oedema. Both values returned to baseline 24 hours after the race, which reflects possible mild and transient pulmonary oedema with minimal physiological significance.

Changes in pulmonary microcirculation after COVID-19

The endothelium is a tissue most vulnerable to the SARS-CoV-2 virus. Systemic endothelial dysfunction leads to the development of endothelitis which causes the main manifestations of the disease and systemic disturbance of microcirculation in various organs. Pulmonary microcirculatory damage, the most striking clinical manifestation, was the reason to perform SPECT to detect microcirculation disorders.Aim. To assess microcirculatory changes in the lungs of patients who had no previous respiratory diseases and had a COVID-19 infection at different times from the onset of the disease.Methods. SPECT data were analyzed in 136 patients who had a proven coronavirus infection of varying severity from May 2020 to June 2021.Results. All patients showed changes in microcirculation in the lungs in the post-COVID period. The severity of microcirculation disorders had a significant correlation (rs = 0.76; p = 0.01) with the degree of damage to the pulmonary parenchyma and an average correlation (rs = 0.48; p = 0.05) with the timing of the post-COVID period and the degree of residual lesions on CT (rs = 0.49; p = 0.01). The examined patients with persistent clinical complaints had pulmonary microcirculatory lesions, which may indicate the development of vasculitis, at all stages of the post-COVID period. Despite regression of the lesions confirmed by CT in 3 to 6 months after the acute COVID-19 infection, specialists from Russian and other countries report that 30–36% of patients develop pulmonary fibrosis. Similar changes were identified in 19.1% of the examined patients in our study.Conclusion. Microcirculation disorders are detected in all patients in the post-COVID period, irrespective of the severity according to CT. Progressive decrease in microcirculation in the lower parts of the lungs, local zones of hypoperfusion with the critically low accumulation of radiopharmaceuticals, persistent areas of compaction of the lung tissue (so-called “ground glass”), reticular changes, and the development of traction bronchiectasis, a decrease in the diffusion capacity of the lungs and alveolar volume may indicate fibrotic lesions with subsequent development of virus-associated interstitial lung disease.

Preliminary Study: Immediate Effect of the Slow Deep Breathing Exercise and Sustained Maximal Inspiration with Volume-Oriented Incentive Spirometry on the Diffusing Lung Capacity in Healthy Young Participants

Slow-deep breathing exercise (SDBE) while using a volume-oriented type of incentive spirometry (VIS) device (SDBE/VIS) is one of the techniques in chest physical therapy designed to improve lung volume and oxygenation. However, the immediate effect of SDBE/VIS paired with a sustained maximal inspiration (SMI) on diffusing lung capacity (DLC), has not been documented. This preliminary study aimed to evaluate the immediate effect of SDBE/VIS paired with the SMI technique on DLC in healthy participants. Twenty healthy sedentary adults (11 males and 9 females) aged 20 to 23 years were recruited into this cross-over study and randomly assigned to one of 2 ordered groups; SDBE/VIS paired with SMI followed by SDBE/VIS alone or SDBE/VIS alone followed by SDBE/VIS with SMI. During each of the 2-testing sessions, the participants performed 3 sets of 5 SDBE/VIS trials which were controlled by ensuring that each participant reached their maximal vital capacity; derived from their pulmonary function test. The DLC for carbon monoxide (DLCO), alveolar volume (VA), and total lung capacity (TLC) was assessed prior to (baseline) and after each of the 5 experimental trials. A 3-min rest period was given between each set of 5 trials and 1 week between testing sessions. The results demonstrated that SDBE/VIS paired with the SMI technique significantly increased both the DLCO (mL/min/mmHg and %) and VA (L and %) when compared to the baseline values. Whereas, SDBE/VIS without using the SMI technique did not alter the DLCO, VA or the DLCO/VA. However, both SDBE/VIS with and without the SMI technique showed a significant increase the TLC (L and %), with the TLC from SDBE/VIS paired with SMI was significantly higher than when the SDBE /VIS was performed without using the SMI technique. Thus, it appears that performing SDBE/VIS exercised paired with the SMI technique has a significant and positive effect on DLC.

Development of lung diffusion to adulthood following extremely preterm birth

BackgroundGas exchange in extremely preterm (EP) infants must take place in foetal lungs. Childhood lung diffusing capacity for carbon monoxide (DLCO) is reduced; however, longitudinal development has not been investigated. We describe growth of DLCO and its sub-components to adulthood in EP-born compared to term-born subjects.MethodsTwo area-based cohorts born at gestational age ≤28 weeks or birth weight ≤1000 grams in 1982–1985 (n=48) and 1991–1992 (n=35) were examined twice, at ages 18 and 25, and 10 and 18 years, respectively, and compared to matched term-born controls. Single-breath DLCO was measured at two oxygen pressures, with sub-components [membrane diffusion (DM) and pulmonary capillary blood volume (VC)] calculated using the Roughton–Forster equation.ResultsAge-, sex- and height-standardized transfer coefficients for carbon monoxide (KCO), and DLCO were reduced in EP-born compared to term-born and remained so during puberty and early adulthood (p-values for all time points and both cohorts ≤0.04), whereas alveolar volume was similar. Development occurred in parallel to term-born controls, with no signs of pubertal catch-up growth nor decline at 25 years (p-values for lack of parallelism within cohorts 0.99, 0.65, 0.71, 0.94, and 0.44 for z-DLCO, z-VA, z-KCO, DM, and VC, respectively). Split by membrane and blood volume components, findings were less clear; however, membrane diffusion seemed most affected.ConclusionPulmonary diffusing capacity was reduced in EP-born compared to term-born, and development from childhood to adulthood tracked in parallel to term-born, with no signs of catch-up growth nor decline at age 25.

Design-Based Stereology of the Lung in the Hyperoxic Preterm Rabbit Model of Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a complex condition frequently occurring in preterm newborns, and different animal models are currently used to mimic the pathophysiology of BPD. The comparability of animal models depends on the availability of quantitative data obtained by minimally biased methods. Therefore, the aim of this study was to provide the first design-based stereological analysis of the lungs in the hyperoxia-based model of BPD in the preterm rabbit. Rabbit pups were obtained on gestation day 28 (three days before term) by cesarean section and exposed to normoxic (21% O2, n = 8 ) or hyperoxic (95% O2, n = 8 ) conditions. After seven days of exposure, lung function testing was performed, and lungs were taken for stereological analysis. In addition, the ratio between pulmonary arterial acceleration and ejection time (PAAT/PAET) was measured. Inspiratory capacity and static compliance were reduced whereas tissue elastance and resistance were increased in hyperoxic animals compared with normoxic controls. Hyperoxic animals showed signs of pulmonary hypertension indicated by the decreased PAAT/PAET ratio. In hyperoxic animals, the number of alveoli and the alveolar surface area were reduced by one-third or by approximately 50% of control values, respectively. However, neither the mean linear intercept length nor the mean alveolar volume was significantly different between both groups. Hyperoxic pups had thickened alveolar septa and intra-alveolar accumulation of edema fluid and inflammatory cells. Nonparenchymal blood vessels had thickened walls, enlarged perivascular space, and smaller lumen in hyperoxic rabbits in comparison with normoxic ones. In conclusion, the findings are in line with the pathological features of human BPD. The stereological data may serve as a reference to compare this model with BPD models in other species or future therapeutic interventions.

A radiological study method of vertical alveolar resorptions using immediate dental implants

Dental extraction is followed by decreases in alveolar volume, vertically and horizontally. This retrospective study measured vertical alveolar resorption after insertion of immediate implants, using OPG, without CBCT or additional radiographs. Patients were randomly split in two groups A (57 implants) and B (47 implants). Measurements were made by two independent observers. The types of implants were: Exacta (Biaggini Medical Devices), Nova, Dentix Millenium and Surcam. The method was based on the size of the implant and another common element of the two radiographs. It used an optimal radiologic exposure. It can be generalized to other studies. Similar results measured in the two groups showed that alveolar remodeling does not depend on the type of the implant. Half of the alveoli did not have any resorption. Another quarter showed barely perceptible clinical resorption (1-2 mm). In the last quarter were registered all the notable resorptions that were associated with various factors (temporary mobile prosthesis, surgical flap, medication and some health problems, smoking, etc.) showing real situations, not ideal conditions. Maximum resorption was unique (7.63 mm).

Lung function and breathing patterns in hospitalised COVID-19 survivors: a review of post-COVID-19 Clinics

Introduction There is relatively little published on the effects of COVID-19 on respiratory physiology, particularly breathing patterns. We sought to determine if there were lasting detrimental effect following hospital discharge and if these related to the severity of COVID-19. Methods We reviewed lung function and breathing patterns in COVID-19 survivors > 3 months after discharge, comparing patients who had been admitted to the intensive therapy unit (ITU) (n = 47) to those who just received ward treatments (n = 45). Lung function included spirometry and gas transfer and breathing patterns were measured with structured light plethysmography. Continuous data were compared with an independent t-test or Mann Whitney-U test (depending on distribution) and nominal data were compared using a Fisher’s exact test (for 2 categories in 2 groups) or a chi-squared test (for > 2 categories in 2 groups). A p-value of < 0.05 was taken to be statistically significant. Results We found evidence of pulmonary restriction (reduced vital capacity and/or alveolar volume) in 65.4% of all patients. 36.1% of all patients has a reduced transfer factor (TLCO) but the majority of these (78.1%) had a preserved/increased transfer coefficient (KCO), suggesting an extrapulmonary cause. There were no major differences between ITU and ward lung function, although KCO alone was higher in the ITU patients (p = 0.03). This could be explained partly by obesity, respiratory muscle fatigue, localised microvascular changes, or haemosiderosis from lung damage. Abnormal breathing patterns were observed in 18.8% of subjects, although no consistent pattern of breathing pattern abnormalities was evident. Conclusions An “extrapulmonary restrictive” like pattern appears to be a common phenomenon in previously admitted COVID-19 survivors. Whilst the cause of this is not clear, the effects seem to be similar on patients whether or not they received mechanical ventilation or had ward based respiratory support/supplemental oxygen.