Background. Intensive therapy of acute renal failure (ARF) in children is one of the most difficult problems in pediatrics, since it involves a complex solution to the problems facing the doctor, requiring both conservative treatment and the use of invasive (hence, aggressive) methods of renal replacement therapy.
Objective. Evaluation of the effect of intensive therapy on changes in the circadian rhythm of stroke output (SO) depending on age.
Material and methods. Data on hourly monitoring of body temperature in 33 children aged 6 months to 18 years with acute renal failure who were admitted to the ICU of the NMCC with oligo-anuria were examined. All patients underwent hemodialysis (HD) under the control of hemodynamics, acid-base status, respiratory system parameters, and received supportive, antibacterial, anti-inflammatory, syndromic corrective intensive therapy.
Results. On admission in the ICU of the NMCC, in 33 children aged from 6 months to 18 years with acute renal failure with oligo-anuria, the circadian rhythm mesor indicators of SO did not differ significantly from age standards. Hourly SO data in the average circadian rhythm of SO corresponded to age-related values. There were no significant differences in the SO indicator between daytime and night hours. Fluctuations in the amplitude of the circadian rhythm occurred in a periweekly manner.
Conclusion. In groups 2 and 1, the periweekly biorhythms of SO were more deformed. The longest inversion of the circadian rhythm was found in children of group 1, which indicated an increased risk of developing acute decompensation of cardiac function in children under 3 years of age.

Keywords: cardiac output, acute renal failure