INVESTIGATIONS OF THE RHYTHMIC FUNCTION OF HEART-RATE, BLOOD-PRESSUREAND TEMPERATURE IN NEONATES

Over a period of 24-30 h in 10 min intervals, the systolic diastolic a nd mean arterial blood pressure, heart rate, rectal and skin temperatu re were measured simultaneously in 17 full-term babies on the 2nd day of life, and in 11 of them again at the age of 4 weeks. Each profile w as analysed individually by the Cosinor method. On the 2nd day of life , a statistically significant circadian rhythm could be detected in 12 of the 17 neonates for systolic blood pressure and heart rate, in 16 for skin temperature and in all 17 neonates for rectal temperature. Su mmarizing the data of the 17 new-borns the circadian rhythm was the mo st frequent component in all functions. A high portion of ultradian rh ythms was observed as well. With increasing postnatal age, the varianc e of acrophases decreased, particularly for the temperature rhythms. T his means that synchronization with the environment is beginning. Furt hermore, we found an increase in the mesor of heart rate and blood pre ssure and an increase in amplitude of temperature.