Changes in cardiac output and cerebral oxygenation during prone and supine sleep positioning in healthy term infants

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

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.

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.

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.