Article

TEMPERATURE REGULATION AND HEAT PRODUCTION IN THE NEWBORN.

Pediatric Clinics of North America (Impact Factor: 1.78). 09/1965; 12:765-79.
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    ABSTRACT: In closed incubators, radiative heat loss (R) which is assessed from the mean radiant temperature (Tr) accounts for 40-60% of the neonate's total heat loss. In the absence of a benchmark method to calculate Tr--often considered to be the same as the air incubator temperature-errors could have a considerable impact on the thermal management of neonates. We compared Tr using two conventional methods (measurement with a black-globe thermometer and a radiative "view factor" approach) and two methods based on nude thermal manikins (a simple, schematic design from Wheldon and a multisegment, anthropometric device developed in our laboratory). By taking the Tr estimations for each method, we calculated metabolic heat production values by partitional calorimetry and then compared them with the values calculated from V(O2) and V(CO2) measured in 13 preterm neonates. Comparisons between the calculated and measured metabolic heat production values showed that the two conventional methods and Wheldon's manikin underestimated R, whereas when using the anthropomorphic thermal manikin, the simulated versus clinical difference was not statistically significant. In conclusion, there is a need for a safety standard for measuring TR in a closed incubator. This standard should also make available estimating equations for all avenues of the neonate's heat exchange considering the metabolic heat production and the modifying influence of the thermal insulation provided by the diaper and by the mattress. Although thermal manikins appear to be particularly appropriate for measuring Tr, the current lack of standardized procedures limits their widespread use.
    Arbeitsphysiologie 12/2011; 112(8):2957-68. · 2.66 Impact Factor
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    ABSTRACT: An increasing body of evidence has revealed that interventions performed during resuscitation of extremely-low-gestational-age neonates (ELGANs) may have a direct influence on the immediate survival and also on long-term morbidity. It has been proposed that interventions in the delivery room and/or hypothermia could trigger changes constitutive of chronic lung disease. New approaches in the first minutes of life using more gentle parameters of intervention are being studied. Thus, titrating inspiratory fraction of oxygen, the use of non-invasive ventilation to reduce trauma to the lung, the use of polyethylene/polyurethane wrapping to avoid hypothermia and delaying cord clamping altogether constitute promising initiatives. The first minutes of life are a valuable window for intervention. However, whilst these practice changes make sense and there are emerging data to support them, further evidence including long-term follow up is needed to definitively change resuscitation procedures in ELGANs.
    Neonatology 01/2009; 95(4):286-98. · 2.57 Impact Factor
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    ABSTRACT: Background Hypothermia incurred during routine postnatal resuscitation is a world-wide issue (across all climates), with associated morbidity and mortality. Keeping vulnerable preterm infants warm is problematic even when recommended routine thermal care guidelines are followed in the delivery suite.Objectives To assess efficacy and safety of interventions, designed for prevention of hypothermia in preterm and/or low birthweight infants, applied within 10 minutes after birth in the delivery suite compared with routine thermal care.Search strategyThe standard search strategy of The Cochrane Collaboration was followed. Electronic databases were searched: MEDLINE (1966 to May Week 4 2004 ), CINAHL (1982 to May Week 4 2004), EMBASE (1974 to 09/07/04), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 3, 2004), Database of Abstracts of Reviews of Effects (DARE 1994 to July 2004), conference/symposia proceedings using ZETOC (1993 to July 2004), ISI proceedings (1990 to 09/07/2004) and OCLC WorldCat (July 2004). Identified articles were cross-referenced. No language restrictions were imposed.Selection criteriaAll trials using randomised or quasi-randomised allocations to test a specific intervention designed to prevent hypothermia, (apart from 'routine' thermal care) applied within 10 minutes after birth in the delivery suite to infants of < 37 weeks' gestational age or birthweight ≤2500 g.Data collection and analysisMethodological quality was assessed and data were extracted for important clinical outcomes including adverse effects of the intervention by at least three independent reviewers. Authors were contacted for missing data. Data were analysed using RevMan 4.2.5. Relative risk (RR), risk difference (RD) and number needed to treat (NNT) with 95% confidence limits were calculated for each dichotomous outcome and mean differences (MD) with 95% confidence limits for continuous outcomes.Main resultsSix studies giving a total of 304 infants randomised and 295 completing the studies were included. Four comparisons to 'routine care' were undertaken within two categories: 1)barriers to heat loss (four studies): plastic wrap or bag (three), stockinet caps (one) and2)external heat sources (two studies): skin-to-skin (one), transwarmer mattress (one).Plastic barriers were effective in reducing heat losses in infants < 28 weeks' gestation (three studies, n = 159; WMD 0.76 °C; 95% CI 0.49, 1.03) but not in the 28 to 31 week group. There was insufficient evidence to suggest that plastic wrap reduces the risk of death within hospital stay (three studies, n = 161; typical RR 0.63; 95% CI 0.32, 1.22; typical RD -0.09; 95% CI -0.20, 0.03). There was no evidence of a significant difference in major brain injury, mean duration of oxygen therapy or hospitalisation for infants < 29 weeks' gestation. Stockinet caps were not effective (borderline significant for infants < 2000 g birthweight) in reducing heat losses.Skin-to-skin care was shown to be effective in reducing the risk of hypothermia when compared to conventional incubator care for infants 1200 to 2199 g birthweight (one study, n = 31; RR 0.09; 95% CI 0.01, 0.64; NNT 2; 2 to 4). The transwarmer mattress significantly kept infants ≤1500 g warmer and reduced the incidence of hypothermia on admission to NICU(one study, n = 24; RR 0.30; 95% CI 0.11, 0.83; NNT 2 range 2 to 4).Authors' conclusionsPlastic wraps or bags, skin-to-skin care and transwarmer mattresses all keep preterm infants warmer, leading to higher temperatures on admission to neonatal units and less hypothermia. Given the low NNT, consideration should be given to using these interventions in the delivery suite. However, the small numbers of infants and studies and the absence of long term follow-up mean that firm recommendations for clinical practice cannot be given. There is a need to conduct large, high quality randomised controlled trials looking at long-term outcomes.PLAIN LANGUAGE SUMMARYSynopsis pending. Copyright © 2006 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
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