Aims The aim of the study was to evaluate tidal breathing patterns in healthy newborns using Structured Light Plethysmography (SLP), and to compare the relative contributions of the ribcage and abdominal compartments in measurements taken pre and post feeding. The opportunities to non invasively measure neonatal lung function are limited. SLP is novel non-invasive method of assessing chest-abdominal wall movement, with potential application in a newborn and infant population.

Methods 17 healthy new-born (7 male and 10 female) from the Rosie Maternity Hospital were studied using SLP-based device, Thora3DiTM. 8 out of 17 were pre-term; corrected gestation age ranged from 35 to 40 weeks. Median weight was 2.866 kg (ranged from 1.985 kg to 4.43 kg). Newborns were in clinically stable condition with no oxygen requirement. No sedation was used.

Pre and post feeding measurements of tidal breaths: inspiration time (ti), expiration time (te), respiration rate. The following parameters were calculated from Konno-Mead (KM) plots: overall phase, spread, principal angle, rotation direction, and ribcage vs. abdomen asymmetry. Principal angle and spread were calculated by performing Principal Component Analysis on the samples comprising the KM loop data. Ribcage vs. abdomen asymmetry was found for each point on the KM loop by evaluating the distance between individual points and the expected response given a zero phase difference. The Brown Forsythe test was used to test equality of group of variances, the Wilcoxon test for equality in mean and median for the paired data, and Mann-Whitney U test for equality in mean and median for the unpaired data. In all cases, a two-tailed test was performed.

Results Respiratory rate, inspiratory and expiratory times remain constant pre and post feeds. The paired samples (n = 8) showed a significant change in variation of ribcage vs. abdomen phase (p < 0.025). The unpaired data (n1 = 13, n2 = 19) showed change in variation of the principal angle, the overall phase and ribcage vs. abdomen phase (p < 0.05). Each data collection took approximately 15 minutes including parental consent.

Conclusion The results indicate that newborn breathing pattern become more stable after feeding, and that SLP provides a non invasive method of assessment of tidal breathing pattern in infants.