Chest physiotherapy for acute wheezing: an inappropriate protocol in a misdiagnosed group of patients

Dear Editor, We read with interest the paper by Olhager on body composition in late preterm infants (1). We wondered why the authors focused mainly on the first 10 days of life, stating that “on day four, most late preterm infants have adapted to extrauterine life”: Micheli, quoted in the paper, reports that fluid and metabolic adaptation to extrauterine life in preterm infants ends during the second postnatal week (2). Despite a lower fat-mass content than term infants at birth, late preterms at full-term had a higher fat mass. However, when this postnatal fat-mass catch-up occurs is unknown. In our sample, at 15 days of life, late preterm infants had a percentage fat mass similar to that of term infants at birth. That is, when birth weight is fully regained and growth resumes (Table 1). As in Olhager and others, late preterm infants had a higher percentage fat mass than term infants at similar postconceptional age (Table 1) (1,3). We think this implies, logically, that they gained more fat mass and less fat-free mass than an hypothetical foetus in utero during the same period. Therefore, in our view, these data do not support Olhager’s conclusion that “in late preterms, the weight gained after the initial postnatal weight loss mainly consisted of a gain in fat-free mass”: in Table 3, late preterm infants’ percentage fat mass doubles from birth to full term (1). In Olhager’s report, full-term postconceptional age of late preterm infants was significantly inferior to that of term infants: this should be included in multivariate analysis when analysing length. Additionally, this might raise doubts about the appropriateness of matching. We agree that late preterm infants’ early growth may be crucial in their later metabolic outcomes: additional well-designed studies are warranted. References 1. Olhager E, T€ornqvist C. Body composition in late preterm infants in the first ten days of life and at full term. Acta Paediatr 2014. doi: 10.1111/apa. 12632 [Epub ahead of print]. 2. Micheli JL, Pfister R, Junod S, Laubscher B, Tolsa JF, Schutz Y, et al. Water, energy and early postnatal growth in preterm infants. Acta Paediatr Suppl 1994; 405: 35–42. 3. Gianni M, Roggero P, Liotto N, Amato O, Piemontese P, Morniroli D, et al. Postnatal catch-up after late preterm birth. Pediatr Res 2012; 72: 637–40.