Changes in pulmonary function in preterm infants recovering from RDS following early treatment with ambroxol: Results of a randomized trial

Abstract

Several studies have demonstrated that ambroxol stimulates surfactant synthesis and has antioxidative and antiinflammatory effects. We investigated the effect of ambroxol on lung function in newborns with respiratory distress syndrome (RDS) weighing <1,500g. In all, 102 newborns were enrolled (52 received ambroxol and 50 placebo). After extubation, lung function tests were performed weekly using a face mask for ventilatory measurements and a catheter tip pressure transducer (diameter 1.7 mm) for esophageal pressure measurements (Pes). The flow‐through technique was used to eliminate apparatus dead space and to allow long‐term measurements during quiet sleep. Percentile curves of pulmonary function parameters from healthy newborns were used for comparison. During the first 28 days, 42 newborns were extubated in the ambroxol group and 36 in the placebo group. The ventilatory parameters of both treatment groups were in the normal range and there were no significant differences between the two groups at any time. After extubation, the ratio of tidal volume to maximal esophageal pressure changes (VT/ Pes,max) was below the 10th percentile in the ambroxol and placebo‐treated groups. In the ambroxol group the 10th percentile was reached on day 10, whereas in the placebo group the 10th percentile was reached significantly later (P < 0.05) on day 23. Modeling of power expenditures was used to identify the optimal breathing pattern so that small differences in ventilatory parameters between the two groups could be analyzed. We conclude that early ambroxol treatment has only a modest effect on lung function in newborns with established RDS. The sensitivity of tidal breathing parameters is not sufficient to detect these small changes in lung mechanics, but small improvements could be demonstrated in lung mechanics 10 days after extubation in the ambroxol‐treated group. Pediatr Pulmonol. 1999; 27:104–112. © 1999 Wiley‐Liss, Inc.

Differential effects of immaturity and neonatal lung disease on the lung function of very low birth weight infants at 48-52 postconceptional weeks

“…Our results indicate a statistically significant effect of immaturity on the breathing pattern at the time of measurement. Very preterm infants had delayed maturation of breathing patterns, with reduced V T , increased RR, due to impaired respiratory mechanics …”

Current methodological and technical limitations of time and volumetric capnography in newborns

“…Furthermore, preterm infants with respiratory deficiency can have a respiratory rates >60/min with exhalation times of <500 ms [35, 36]. Energetically, this is an optimal breathing strategy for infants with stiff lungs, as it reduces the work of breathing [37]. However, this breathing strategy results in a technical challenge in capnographic measurements using currently available equipment.…”

Comprehensive integrated spirometry using raised volume passive and forced expirations and multiple-breath nitrogen washout in infants

“…Tidal breathing parameters neither reliably discriminated between healthy infants and the ones with lung disease nor distinguished types or levels of respiratory dysfunction. (Clarke et al, 1994; Seddon et al, 1996; Paetow et al, 1999; Schmalisch et al, 1999, 2005; Ranganathan et al, 2003). We previously reported measurements of fractional lung volumes and total lung capacity (TLC) at V 30 in infants with cystic fibrosis (Morris, 1999b).…”