Long Term Effect of Prematurity and Respiratory Morbidity on Cardiopulmonary Exercise Testing in Childhood

Ronen Bar-Yoseph Lea Bentur Yara Haddad Hanna Moneera Merav Zucker-Toledano Gur Mainzer Julie Haddad Amir Kugelman Ori Hochwald

Rambam Health Care Campus, Haifa, Israel

Background: Preterm birth is a major determinant of neonatal morbidity. Most of the studies focus on early preterm infants (born under 30 weeks of gestation age (WGA)) with significant morbidity such as bronchopulmonary dysplasia (BPD), a common complication in early preterm infants. In recent years, there has been a growing interest in late preterms born several weeks prematurely (weeks 34+0 - 36+6) and constituting the largest group among preterms. There is scarce data regarding the short- and long-term effects of this interesting group.

Aim: To evaluate the long-term effect of prematurity on exercise capacity in childhood.

Methods: We studied children aged 7-10 years in three groups: 1) “Early preterm” – infants born before 30 WGA with BPD, 2) “Late preterm” – preterm infants born between 34+0/7 and 36+6/7 WGA, and 3) Control group of healthy children born week 37+0 (“term”). All participants completed a comprehensive functional evaluation using a cardiopulmonary exercise test (CPET). The primary outcome was exercise capacity as measured by maximal oxygen uptake (VO2max); secondary outcomes included lung functions and other parameters from the CPET.

Results: Sixty-two children were recruited to our study, 22 “early preterm” children (age 9.77±1.07), 18 “late preterm” children (age 9.93±0.86), and 22 “term” children (age 8.86±0.97). Lung function in the early preterms was significantly lower (FEV1 = 78.4 ± 15.0% pred) compared to the late preterms (FEV1 = 89.6 ± 17.3% pred, p = 0.012) and the term group (FEV1=91.1 ± 12.4% pred, p=0.024). No difference in lung functions was found between the late preterm and the control groups. A statistically significant difference in the VO2 was found between the late preterm and the term groups (37.2 ± 7.10 ml/min/kg, p = 0.036 and 89.8 ± 15.6% of predicted p = 0.005 compared with 45.6 ± 7.4 ml/min/kg and 113.4 ± 17.0% of predicted, respectively). The term group had a higher oxygen pulse (120.3 ± 18.9%pred, p 0.005) than the early preterm (99.8 ± 25.2%pred) and late preterm groups (93.4 ± 15.2%pred). Low respiratory reserve was demonstrated to be slightly higher in the preterm groups compared to the term group. Oxygen saturation were normal and without differences between the different groups.

Conclusions: This study demonstrated a lower exercise capacity in children aged 7-10 years with a history of late prematurity compared to healthy term children and with no difference from children with a history of early prematurity and BPD. Data regarding morbidity and possible functional limitations may help in adapting a personalized approach to patients and their families of an active lifestyle, regular exercise, improving exercise capacity, and monitoring for possible exercise limitations. Further large studies are needed to better understand the specific characteristics of different preterm populations.

Ronen Bar-Yoseph

Pediatric Pulmonary Institute, Ruth Children’s Hospital, Rambam Health Care Campus, Haifa, Israel

Dr. Ronen Bar-Yoseph is an senior pulmonologist at the Pediatric Pulmonology Institute and head of the Children's Physical Activity and Exercise Clinic and Lab at Rambam Health Care Campus. Dr. Bar-Yoseph received his medical degree (cum laude) in 2002 from the Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, and completed his residency in pediatrics (cum laude) and a clinical fellowship in pediatric pulmonology, both at Rambam. Dr. Bar-Yoseph had completed a 2 year research fellowship at the Pediatric Exercise and Genomic Research Center at University of California, Irvine, under the supervision of Dr. Shlomit Radom-Aizik and Dr. Dan Cooper. Dr. Bar-Yoseph has participated in a wide range of clinical and basic research projects. His main research interest are physical activity and exercise in health and chronic conditions, particularly in the pediatric population (i.e. - asthma, cystic fibrosis, childhood malignancies, and congenital heart disease) from basic research to the clinic and back, translational science and physical activity as a tool for personalized medicine (Exercise Is Medicine)