2.50
Hdl Handle:
http://hdl.handle.net/10755/158160
Type:
Presentation
Title:
Correlating VLBW Infant Autonomic Response to Temperature and Oxygen
Abstract:
Correlating VLBW Infant Autonomic Response to Temperature and Oxygen
Conference Sponsor:Western Institute of Nursing
Conference Year:2005
Author:Doig, Alexa, RN, MS
P.I. Institution Name:University of Utah
Title:Doctoral Student
Co-Authors:Sandra L. Smith, Adrian Musters
Aims: To examine the use of growth curve methods in very-low-birth-weight (VLBW) infant autonomic nervous system (ANS) activity in response to fluctuations in oxygenation and temperature. Methodological issues and sources of error in growth curve modeling will also be explored. Background: Power spectral analysis of heart period variability reveals two frequency regions which isolate the effects of sympathetic and parasympathetic control over heart rate. The high-frequency (HF) power region provides a measure of parasympathetic tone, while the low-frequency (LF) power region represents primarily sympathetic tone. These calculated variables can then be used as a precise measure of an infant's response to external events, such as fluctuations in temperature or oxygenation. Premature infants have a reduced capacity to maintain body temperature, in part due to an immature nervous system. In addition, the normal thermogenic effect of feeding has not been well documented in this infant population. Decreased oxygenation is a stressor that has the potential to activate the 'fight or flight' response. Methods: A secondary analysis was conducted on data derived from an experimental study comparing infant physiologic response to incubator care versus maternal holding. The original study was a two group crossover design with interrupted time series data collection. HPV, temperature, FiO2, and SaO2 data were collected from 16 mechanically ventilated VLBW infants in a neonatal intensive care unit. Data were collected for four days in 5 minute epochs during an 8 hour period which included an enteral feeding. Daily trends in HF and LF power measured in ms2 were analyzed using individual growth curve analysis techniques. Slopes and intercepts for heart period power were then correlated to infant temperature and oxygenation. Results: Slope of HF power was negatively correlated to FiO2 (r = -0.46, p = .076) suggesting that as parasympathetic activity increased, infant oxygen requirement decreased. Slope of HF power was positively correlated to flank temperature (r = 0.50, p = .047) indicating that temperature increased as parasympathetic activity increased. Confirming this thermogenic effect was a significant correlation between HF power at the time of feeding and flank temperature (r = 0.56, p = 0.024). Other results were less supportive of the physiological models. Nonsignificant results will also be discussed. Conclusions: Growth curve modeling is a potentially useful tool for analyzing trends in physiological data. Strengths and weaknesses of this technique for analyzing trends in ANS activity will be discussed. Although the sample size limitation increased the likelihood of type I and II error, these results will be used as pilot data to power a new study to further explore the relationship between ANS responses and a range of physiological variables.
Repository Posting Date:
26-Oct-2011
Date of Publication:
17-Oct-2011
Sponsors:
Western Institute of Nursing

Full metadata record

DC FieldValue Language
dc.typePresentationen_GB
dc.titleCorrelating VLBW Infant Autonomic Response to Temperature and Oxygenen_GB
dc.identifier.urihttp://hdl.handle.net/10755/158160-
dc.description.abstract<table><tr><td colspan="2" class="item-title">Correlating VLBW Infant Autonomic Response to Temperature and Oxygen</td></tr><tr class="item-sponsor"><td class="label">Conference Sponsor:</td><td class="value">Western Institute of Nursing</td></tr><tr class="item-year"><td class="label">Conference Year:</td><td class="value">2005</td></tr><tr class="item-author"><td class="label">Author:</td><td class="value">Doig, Alexa, RN, MS</td></tr><tr class="item-institute"><td class="label">P.I. Institution Name:</td><td class="value">University of Utah</td></tr><tr class="item-author-title"><td class="label">Title:</td><td class="value">Doctoral Student</td></tr><tr class="item-email"><td class="label">Email:</td><td class="value">alexa.doig@nurs.utah.edu</td></tr><tr class="item-co-authors"><td class="label">Co-Authors:</td><td class="value">Sandra L. Smith, Adrian Musters</td></tr><tr><td colspan="2" class="item-abstract">Aims: To examine the use of growth curve methods in very-low-birth-weight (VLBW) infant autonomic nervous system (ANS) activity in response to fluctuations in oxygenation and temperature. Methodological issues and sources of error in growth curve modeling will also be explored. Background: Power spectral analysis of heart period variability reveals two frequency regions which isolate the effects of sympathetic and parasympathetic control over heart rate. The high-frequency (HF) power region provides a measure of parasympathetic tone, while the low-frequency (LF) power region represents primarily sympathetic tone. These calculated variables can then be used as a precise measure of an infant's response to external events, such as fluctuations in temperature or oxygenation. Premature infants have a reduced capacity to maintain body temperature, in part due to an immature nervous system. In addition, the normal thermogenic effect of feeding has not been well documented in this infant population. Decreased oxygenation is a stressor that has the potential to activate the 'fight or flight' response. Methods: A secondary analysis was conducted on data derived from an experimental study comparing infant physiologic response to incubator care versus maternal holding. The original study was a two group crossover design with interrupted time series data collection. HPV, temperature, FiO2, and SaO2 data were collected from 16 mechanically ventilated VLBW infants in a neonatal intensive care unit. Data were collected for four days in 5 minute epochs during an 8 hour period which included an enteral feeding. Daily trends in HF and LF power measured in ms2 were analyzed using individual growth curve analysis techniques. Slopes and intercepts for heart period power were then correlated to infant temperature and oxygenation. Results: Slope of HF power was negatively correlated to FiO2 (r = -0.46, p = .076) suggesting that as parasympathetic activity increased, infant oxygen requirement decreased. Slope of HF power was positively correlated to flank temperature (r = 0.50, p = .047) indicating that temperature increased as parasympathetic activity increased. Confirming this thermogenic effect was a significant correlation between HF power at the time of feeding and flank temperature (r = 0.56, p = 0.024). Other results were less supportive of the physiological models. Nonsignificant results will also be discussed. Conclusions: Growth curve modeling is a potentially useful tool for analyzing trends in physiological data. Strengths and weaknesses of this technique for analyzing trends in ANS activity will be discussed. Although the sample size limitation increased the likelihood of type I and II error, these results will be used as pilot data to power a new study to further explore the relationship between ANS responses and a range of physiological variables.</td></tr></table>en_GB
dc.date.available2011-10-26T20:34:08Z-
dc.date.issued2011-10-17en_GB
dc.date.accessioned2011-10-26T20:34:08Z-
dc.description.sponsorshipWestern Institute of Nursingen_GB
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