Abstract 74

Background: Alterations of cerebral blood flow velocity measured by Doppler sonography were described during blood sampling from an UAC (J Perinatol 1996;15:341-5). Aims. To assess whether blood sampling from an UAC induces changes in cerebral blood volume and oxygenation measured by near infrared spectroscopy (NIRS). Subjects/ Measurements. 12 infants, median birth weight 990 gm (660-1500 gm), median GA 26 wk (23-30 wk) were studied during routine blood sampling from an UAC in the high position (day one or two of life). Mean time of aspiration 36 sec, time of replacement 20 sec, volume, aspirated 3,4 ml/kg. Using NIRS, cerebral deoxygenated hemoglobin (HHb), O2Hb and tHb concentration changes were measured, heart rate, oxygen saturation, TcPO2, TcPO2 were registered every second before, during and after blood sampling. Mean values were calculated for 120 sec before sampling, last 10 sec of aspiration, last 10 seconds of replacement, and 120 sec after replacement. Statistics: paired t-test. Results. tHb and O2Hb decreased from baseline during aspiration (p=0,034 and p=0,013), during replacement (p=0,07 and p=0,037), and after replacement (p= 0,012 and p=0,005). Heart rate increased significantly after sampling (p=0,03). Hhb, oxygen saturation, TcPO2, TcPCO2, and blood pressure did not change. Conclusion. Blood sampling from an UAC induces a decrease in cerebral blood volume and cerebral oxygenation.