Effects of postnatal environmental tobacco smoke on cardio-respiratory control in newborn lambs

While prenatal environmental tobacco smoke (ETS) exposure has been shown to be a major cause of sudden infant death syndrome, the effects of postnatal ETS exposure have been less studied. The objective of this study is to explore the effects of 15-days postnatal exposure to 20 cigarettes/day on heart rate variability (HRV), respiratory rate variability (RRV) and cardiorespiratory interrelations in newborn lambs. On postnatal day 16, six-hours polysomnographic recording was obtained from six control lambs exposed to room air (group C0) and six lambs exposed to 20 cigarettes/day (group C20) for the first 15 days of life. ECG and respiratory movements (RSP) were continuously monitored. Several analyses were performed on these signals, including heart rate variability analyses (on the RR intervals extracted from the ECG), respiratory rate variability analyses (on different time series extracted from the breathing signal) and cardiorespiratory interrelations analyses (on both the RR interval and the breathing signal). The results suggest that ETS exposure for the first 15 postnatal days leads to slight alterations of cardiorespiratory control, which predominate on respiration.