Biological rhythm development in preterm infants: Does health status influence body temperature circadian rhythm?

Abstract

Twenty-six preterm infants, postconceptional age from 28 to 35 weeks and postnatal age approximately 14 days, were included in a study of the development of temperature circadian rhythm. Insulated abdominal skin temperature and incubator air temperature were recorded continuously at 1-min intervals for 24 hr. Using cosinor analysis, cycle mesor, amplitude, and acrophase were determined. Initial results from regression analysis did not confirm a predicted linear relationship between postconceptional age and amplitude; however, dividing the sample according to health status into sick (N = 15) and not sick (N = 11) groups revealed differing regression models. For not sick infants, amplitude increased with postconceptional age (R(2) =.405), whereas no relationship was found between postconceptional age and cycle amplitude in sick infants (R(2) =.069). These results indicate that healthy preterm infants demonstrate emergence of circadian temperature rhythm. Implications include potential time-based periods of vulnerability, overheating and hyperthermia, and management of incubator operation.

Frequency analysis of air and skin temperature in neonates in servo-controlled incubators

“…The periods of maximum coherence in our study are equivalent to the most important periods of cyclic changes of single parameters found using other methods. 20 This pilot study has several limitations. First, the number of patients was limited by slow recruitment and availability of only one temperature probe generously provided by the company.…”

“…19 The amplitude of neonatal ultradian rhythms of abdominal skin temperature increases with postconceptional age in healthy but not in sick preterm infants. 20 Neonatal ultradian rhythms of temperature, heart rate and activity patterns may be influenced by schedules of infant care, feeding and physical contact. 1,2 Cycles of cardiovascular regulation usually range between 1 s and several minutes.…”

The Promise of the State Space Approach to Time Series Analysis for Nursing Research

“…Examples in the nursing literature include abdominal temperature collected every minute for 32 days in female adults (Padhye & Hanneman, 2007) and every minute for 24 hours in preterm infants (Thomas, 2001), and infant activity summarized every 15 seconds for 4 days (Thomas & Burr, 2008). Each empirical time series is conceived as the realization of a data generating process that governs the movement of variables over time (Shumway & Stoffer, 2006).…”

“…Nursing researchers have used cosinor analysis to describe the cyclic nature of physiological phenomena (Halberg, 1969; Lentz, 1990; Padhye & Hanneman, 2007; Thomas 2001; Thomas & Burr, 2008; Tsai et al, 2011). In this method, a cosine wave with some specified period (often 24 hours) is fit to measurements collected every minute (or second).…”

“…Certain characteristics of the fitted wave pattern are then quantified such as the amplitude and the acrophase (time at which the maximum amplitude is reached). Thomas (2001) used cosinor analysis in the study of circadian rhythms in the temperature of preterm infants. Padyhe and Hanneman (2007) examined the use of cosinor analysis with a long time series of temperature data from both humans and animals.…”