title: [Rhythmic fluctuations in hemoglobin oxygen affinity in premature infants over the space of 24 hours].
abstract: The noninvasive method for estimating the affinity of hemoglobin for oxygen (expressed as P50, oxygen tension at 50% hemoglobin saturation) allowed the authors to follow its time variations. Significant changes of P50 during 24 hours were demonstrated to occur in 16 preterm babies (the gestational age 30-37 weeks, body weight 1850-3000 g) with perinatal encephalopathy, along with fluctuations of tcpCO2, tcpO2, and SpO2. The changes of all these variables were rhythmic; the periods of best fitting cosine curves for P50 were 3-35 hours; double amplitudes, 2.92-17.42 mm Hg; the midline estimating statistics of rhythm, 18.2-33.7 mm Hg. There was a significant correlation between tcpO2 and P50 in 10 babies; in 7 cases, the acrophases of their rhythms coincided (the mean difference was 0.06 +/- 1.1 h). Thus, P50 in preterm babies is varying during a day, it varies periodically, in some cases the variations are due to the changes in pCO2.
authors.forename: G V
authors.initials: GV
authors.lastname: Iatsyk
authors.forename: M D
authors.initials: MD
authors.lastname: Mitish
authors.forename: E V
authors.initials: EV
authors.lastname: Siutkina
authors.forename: A E
authors.initials: AE
authors.lastname: Grigor'ev
authors.forename: A S
authors.initials: AS
authors.lastname: Abramian
mesh_terms: D000328:Adult; D001785:Blood Gas Monitoring, Transcutaneous; D001927:Brain Diseases / Q000097:blood / Q000628:therapy; D002648:Child; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D010102:Oxygen Inhalation Therapy; D010108:Oxyhemoglobins / Q000032:analysis*; D010313:Partial Pressure; D011184:Postoperative Period
chemical_list: D010108:Oxyhemoglobins
vernacular_title: Ritmicheskie kolebaniia srodstva gemoglobina k kislorodu u nedonoshennykh deteĭ na protiazhenii sutok.