Objective To investigate the changes in systemic and cerebral haemodynamics between supine and prone sleep in healthy term infants during the early postnatal period.

Design/methods Healthy term infants without congenital anomalies, patent ductus arteriosus and/or small for gestational age status were enrolled. Infants were placed in supine (SP₁), prone (PP) and back in supine (SP₂) position for 15 min each while asleep. Cardiac output (CO) and stroke volume (SV) were assessed by electrical velocimetry (EV) and echocardiography (echo), and cerebral regional oxygen saturation (CrSO₂) in the frontal lobes was monitored by near-infrared spectroscopy. Heart rate (HR) and SpO₂ were continuously monitored by conventional monitoring.

Results In 34 healthy term infants (mean age 3.7±1.2 days; 16 females), 66 sets of serial CO measurements (34 EV and 32 echo) in three sleep positions were obtained. Mean CO_EV and CO_echo were 182±57 (SP₁), 170±50 (PP) and 177±54 (SP₂), and 193±48 (SP₁), 174±40 (PP) and 192±50 (SP₂) mL/kg/min, respectively. Mean SV_EV and SV_echo were 1.46±0.47 (SP₁), 1.36±0.38 (PP) and 1.37±0.39 (SP₂), and 1.54±40 (SP₁), 1.38±0.38 (PP) and 1.51±0.41 (SP₂) mL/kg, respectively. Repeated measures analysis of variance revealed a decrease in CO and SV during prone positions by both EV and echo, while HR, SpO₂ and CrSO₂ did not change. Thirty-eight per cent of the CO measurements decreased≥10% during prone positioning.

Conclusions In healthy term infants, CO decreases in prone position due to a decrease in SV and not HR. CO recovers when placed back in supine. However, frontal lobe CrSO₂ does not change in the different positions.