Abstract 1177 Poster Session IV, Tuesday, 5/4 (poster 268)

Background: The relationship between infants' behavioral states and cerebral blood flow velocity (CBFV) has been studied by 3 different Doppler techniques with contradictory results. The importance of the behavioral state during CBFV measurements is unclear. We did a prospective study to investigate this relationship with two pulsed-wave Doppler techniques: color duplex Doppler sonography (CDD) and blind transcranial Doppler sonography (TCD).

Methods: We studied 11 healthy newborns (GA 40±1 wks and BW 3612±518 g) on day 2 of life. CBFV was assessed in the middle cerebral artery by the trans-temporal approach. Each infant was consecutively examined by three investigators with both Doppler techniques (CDD by Acuson 128XP, 2.0 MHz linear transducer, and TCD by DWL Multi-Dop X, buttonshaped 2.0 MHz probes). All studies were videorecorded for later analysis of infants' behavioral state according to the Prechtl classification. For artifact detection heart rate and thoracic impedance were also recorded (HP68S-monitor). A total of 6 measurements per infant with each Doppler device was obtained. The measurements began 30 min after breast feeding at about 7 pm and continued until 10 pm. For each Doppler-recording the median of a 1-min artifact-free period was used for statistical analysis. The data were analyzed for peak-systolic (Vmax), mean (Vmean), and end-diastolic (Vmin) blood flow velocity using the multifactorial analysis of variance (SAS).

Results: Since infants were mostly asleep we compared the 2 sleep states quiet and active sleep (CDD, 33 and 29 recordings; TCD 27 and 34 recordings, respectively). We found no statistical difference in absolute values of CBFV parameters between quiet sleep and active sleep. This was true for both Doppler techniques. For CDD recordings the mean differences between the sleep states (quite - active) were: V max -0.33 cm/s (SE 1.495, p=0.824), V mean -0.01 cm/s (SE 1.060, p=0.990) and V min -0.07 cm/s (SE 0.489, p=0.894), whereas for TCD recordings: V max 3.20 cm/s (SE 1.677, p=0.064), V mean 2.26 cm/s (SE 1.122, p=0.051) and V min 1.64 cm/s (SE 0.858, p=0.063). There was no systematical investigator bias.

Conclusions: Our data indicate that there is no difference in CBFVs between quiet and active sleep. Future Doppler studies may not need to differentiate between sleep states if only absolute values of CBFV are analyzed. However, the behavioral state may be important if the variability of CBFV over time is to be analyzed.

Funded by the Austrian Research Foundation, Vienna (FWF-Project Nr. 9342-Med)