Body temperature of newborns: what is normal?

Normal range and risk factors for deviating body temperatures during the first 24 hours in term-born infants under standardised care: an observational study

OBJECTIVE

Body temperature for a known ambient temperature is not known for infants born at term. We aimed to determine the normal range and the incidences of hypothermia and hyperthermia during the first 24 hours of life in healthy term-born infants nursed according to WHO recommendations.

DESIGN

Prospective observational study.

SETTING

Norwegian single centre district hospital. Infants were observed during skin-to-skin care or when dressed in cots.

PARTICIPANTS

Convenience sample of 951 healthy infants born at term.

METHODS

Delivery room temperature was aimed at 26-30°C and rooming-in temperature at 24°C. We measured rectal and room temperatures at 2, 4, 8, 16 and 24 hours of age.

MAIN OUTCOME MEASURES

Percentile curves for rectal temperature. Proportions and risk factors for hypothermia and hyperthermia.

RESULTS

The mean (SD) room temperature was 24.0°C (1.1), 23.8°C (1.0), 23.8°C (1.0)., 23.7°C (0.9) and 23.8°C (0.9). The median (2.5, 97.5 percentile) rectal temperature was 36.9°C (35.7-37.9), 36.8°C (35.9-37.5), 36.9°C (36.1-37.5), 37.0°C (36.4-37.7) and 37.1°C (36.5-37.7). Hypothermia (<36.5°C) occurred in 28% of the infants, 82% of incidents during the first 8 hours. Risk factors for hypothermia were low birth weight (OR 3.1 (95% CI, 2.0 to 4.6), per kg), male sex, being born at night and nursed in a cot versus skin to skin. Hyperthermia (>37.5°C) occurred in 12% and most commonly in large infants after 8 hours of life. Risk factors for hyperthermia were high birth weight (OR 2.2 (95% CI, 1.4 to 3.5), per kg), being awake, nursed skin to skin and being born through heavily stained amniotic fluid.

CONCLUSIONS

Term-born infants were at risk of hypothermia during the first hours after birth even when nursed in an assumed adequate thermal environment and at risk of hyperthermia after 8 hours of age.

Does Accidental Hypothermia Increase Morbidity and Mortality in Mature Neonates?

Accidental hypothermia in mature neonates requiring hospitalization is a clinical complication that has not been studied in detail. In the present study, the effect of accidental hypothermia on common morbidity in neonates in the postnatal period was investigated. We did temperature measurements in 616 mature neonates after birth, after transfer to the maternity ward and at check-up at age of 48-72 hours of life. Additionally, nurses checked temperature until discharge at every diaper change in 302 of all included neonates who were small for gestational age (SGA) or whose mothers had green fluid or premature rupture of membranes (PROM). We investigated if there was a correlation between infection, hyperbilirubinemia, hypoglycemia, SGA, gestational diabetes, PROM, green amniotic fluid, positive GBS status of the mother, and accidental hypothermia in the first 48-72 hours of life. Mature neonates showed transient accidental hypothermia in the first 24 hours of life. No significant correlation between infection (p=0.571), hyperbilirubinemia (p=0.837), hypoglycemia (p=0.072), and accidental hypothermia could be seen. There was a significant correlation between SGA (p=0.020), PROM (p=0.008), and accidental hypothermia, while hyperthermia was associated with infection (p=0.009) and green amniotic fluid (p=0.004). SGA and PROM represent perinatal risk factors for postnatal transient accidental hypothermia in mature neonates. Increased morbidity or mortality associated with postnatal accidental hypothermia has not been demonstrated.Akzidentelle Hypothermie bei Reifgeborenen, die einer Hospitalisierung bedürfen, ist eine bisher nicht näher analysierte klinische Komplikation. In der vorliegenden Arbeit wurde die Abhängigkeit einer akzidentellen Hypothermie von typischen Erkrankungen der Postnatalperiode untersucht. Wir führten bei 616 Reifgeborenen Temperaturmessungen nach Geburt, nach Verlegung auf die Wochenstation und bei der Vorsorgeuntersuchung U2 durch. Zusätzlich kontrollierten wir bei 302 der 616 Neugeborenen mit Small for gestational age (SGA), grünem Fruchtwasser oder vorzeitigem Blasensprung (PROM) die Temperatur bei jedem Windelwechsel bis zur Entlassung. Wir untersuchten, ob es einen Zusammenhang zwischen Infektion, Hyperbilirubinämie, Hypoglykämie, SGA, Gestationsdiabetes, PROM, grünem Fruchtwasser, positivem GBS-Status der Mutter und akzidenteller Auskühlung innerhalb der ersten 48-72 Lebensstunden gab. Reifgeborene zeigten in den ersten 24 Lebensstunden transiente akzidentelle Hypothermien. Es konnte kein signifikanter Zusammenhang zwischen Infektion (P=0.571), Hyperbilirubinämie (p=0.837), Hypoglykämie (p=0.072) und akzidenteller Hypothermie festgestellt werden. Es bestand ein signifikanter Zusammenhang zwischen SGA (p=0.020), PROM (p=0.008) und akzidenteller Hypothermie, während Hyperthermie war mit Infektion (p=0.009) und grünem Fruchtwasser (p=0.004) assoziiert war. SGA und PROM stellen perinatale Risikofaktoren für postnatale transiente, akzidentelle Hypothermien bei Reifgeborenen dar. Eine erhöhte Morbidiät bzw. Mortalität im Zusammenhang mit postnataler akzidenteller Hypothermie konnte nicht nachgewiesen werden.

Diffuse Optical Monitoring of Cerebral Hemodynamics and Oxygen Metabolism during and after Cardiopulmonary Bypass: Hematocrit Correction and Neurological Vulnerability

Cardiopulmonary bypass (CPB) provides cerebral oxygenation and blood flow (CBF) during neonatal congenital heart surgery, but the impacts of CPB on brain oxygen supply and metabolic demands are generally unknown. To elucidate this physiology, we used diffuse correlation spectroscopy and frequency-domain diffuse optical spectroscopy to continuously measure CBF, oxygen extraction fraction (OEF), and oxygen metabolism (CMRO2) in 27 neonatal swine before, during, and up to 24 h after CPB. Concurrently, we sampled cerebral microdialysis biomarkers of metabolic distress (lactate-pyruvate ratio) and injury (glycerol). We applied a novel theoretical approach to correct for hematocrit variation during optical quantification of CBF in vivo. Without correction, a mean (95% CI) +53% (42, 63) increase in hematocrit resulted in a physiologically improbable +58% (27, 90) increase in CMRO2 relative to baseline at CPB initiation; following correction, CMRO2 did not differ from baseline at this timepoint. After CPB initiation, OEF increased but CBF and CMRO2 decreased with CPB time; these temporal trends persisted for 0-8 h following CPB and coincided with a 48% (7, 90) elevation of glycerol. The temporal trends and glycerol elevation resolved by 8-24 h. The hematocrit correction improved quantification of cerebral physiologic trends that precede and coincide with neurological injury following CPB.

Physiological vital sign reference ranges for well late preterm newborns calculated during a typical two-hour newborn period between 2 hours and 7 days of life

Objectives To calculate 95% reference ranges for heart rate, respiratory rate, oxygen saturation, temperature and blood pressure for well late preterm newborns between 34+0/7 and 36+6/7 weeks of gestation during typical neonatal behaviour. Approach A single site, prospective cohort study in a major Australian quaternary hospital between February and September 2019. A total of 120 late preterm newborns had their heart rate, respiratory rate and oxygen saturation measurements recorded every two seconds for up to two hours with unconditional 95% reference ranges determined using a linear mixed model with random intercept for total standard deviation calculation including repeated measures. Temperature and blood pressure measurements were collected twice - at the start and conclusion of the data recording period, with weighted 2.5th and 97.5th percentiles calculated using the mean value. Main results A total of 364,577 heart rate, 365,208 respiratory rate, 360,494 peripheral oxygen saturation, and 240 temperature and blood pressure values were obtained. The 95% reference ranges were: heart rate 102 - 164 bpm; respiratory rate 15 - 67 rpm; oxygen saturation 94 - 100%; temperature 36.4 - 37.6°C; systolic blood pressure 51 - 86 mmHg; diastolic blood pressure 28 - 61 mmHg; mean arterial pressure 35 - 68 mmHg. Significance Seven vital sign references ranges were reported for the late preterm population during a typical newborn period (such as crying, sleeping, feeding, awake and alert, and during nappy hygiene cares); internal and external validation should be completed prior to clinical use. Cut off points for escalation of care have previously been generalised to all newborns irrespective of gestational age which may result in over-treatment or a delay in recognising subtle signs of deterioration.

Association between Regional Tissue Oxygenation and Body Temperature in Term and Preterm Infants Born by Caesarean Section

Body temperature (BT) management remains a challenge in neonatal intensive care, especially during resuscitation after birth. Our aim is to analyze whether there is an association between the BT and cerebral and peripheral tissue oxygen saturation (crSO₂/cTOI and prSO₂), arterial oxygen saturation (SpO₂), and heart rate (HR). The secondary outcome parameters of five prospective observational studies are analyzed. We include preterm and term neonates born by Caesarean section who received continuous pulse oximetry and near-infrared spectroscopy monitoring during the first 15 min, and a rectal BT measurement once in minute 15 after birth. Four-hundred seventeen term and 169 preterm neonates are included. The BT did not correlate with crSO₂/cTOI and SpO₂. The BT correlated with the HR in all neonates (ρ = 0.210, p < 0.001) and with prSO₂ only in preterm neonates (ρ = −0.285, p = 0.020). The BT was lower in preterm compared to term infants (36.7 [36.4–37.0] vs. 36.8 [36.6–37.0], p = 0.001) and prevalence of hypothermia was higher in preterm neonates (29.5% vs. 12.0%, p < 0.001). To conclude, the BT did not correlate with SpO₂ and crSO₂/cTOI, however, there was a weak positive correlation between the BT and the HR in the whole cohort and a weak correlation between the BT and prSO₂ only in preterm infants. Preterm neonates had a statistically lower BT and suffered significantly more often from hypothermia during postnatal transition.

Non-invasive optical neuromonitoring of the temperature-dependence of cerebral oxygen metabolism during deep hypothermic cardiopulmonary bypass in neonatal swine

Management of deep hypothermic (DH) cardiopulmonary bypass (CPB), a critical neuroprotective strategy, currently relies on non-invasive temperature to guide cerebral metabolic suppression during complex cardiac surgery in neonates. Considerable inter-subject variability in temperature response and residual metabolism may contribute to the persisting risk for postoperative neurological injury. To characterize and mitigate this variability, we assess the sufficiency of conventional nasopharyngeal temperature (NPT) guidance, and in the process, validate combined non-invasive frequency-domain diffuse optical spectroscopy (FD-DOS) and diffuse correlation spectroscopy (DCS) for direct measurement of cerebral metabolic rate of oxygen (CMRO₂). During CPB, n = 8 neonatal swine underwent cooling from normothermia to 18℃, sustained DH perfusion for 40 min, and then rewarming to simulate cardiac surgery. Continuous non-invasive and invasive measurements of intracranial temperature (ICT) and CMRO₂ were acquired. Significant hysteresis (p < 0.001) between cooling and rewarming periods in the NPT versus ICT and NPT versus CMRO₂ relationships were found. Resolution of this hysteresis in the ICT versus CMRO₂ relationship identified a crucial insufficiency of conventional NPT guidance. Non-invasive CMRO₂ temperature coefficients with respect to NPT (Q₁₀ = 2.0) and ICT (Q₁₀ = 2.5) are consistent with previous reports and provide further validation of FD-DOS/DCS CMRO₂ monitoring during DH CPB to optimize management.

Surface Body Temperature of Full-Term Healthy Newborns Immediately after Birth-Pilot Study

The aim of the study was to perform an evaluation of chosen body surface temperatures in neonates immediately after birth, and to seek a relationship between those temperatures and the factors related both to the mother and newborn. The study included 74 healthy newborns. Maternal age, body weight, body mass index before pregnancy and on delivery day, birth and pregnancy order, newborn sex, birth weight, body length, pregnancy week on delivery, as well as newborn gasometric test results were collected. The highest temperature values were observed in the chest of the newborn. Significant relationships between the temperature of the evaluated areas were found. The parameters that correlated positively with the temperature of the back region were maternal body weight (both before pregnancy and on delivery day) as well as weight gain during pregnancy. The core and surface temperatures of the body are one of the most important elements of neonatal homeostasis and any changes constitute a risk to the newborn's health. It seemed that according to the surface temperature, the most important area that must be evaluated is the neonate's back, as it is most affected by appropriate weight gain during pregnancy.

Effect of Timing of the First Bath on a Healthy Newborn's Temperature

OBJECTIVE

To determine if a healthy newborn's age in hours (3, 6, or 9 hours after birth) affects thermoregulatory status after the first bath as indicated by axillary and skin temperatures.

DESIGN

Quasi-experimental, mixed-model (between subjects and within subjects) design with hours of age as the nonrepeated variable and prebath and postbath temperatures as the repeated variables.

SETTING

Family-centered care unit at an urban hospital in the southwestern United States.

PARTICIPANTS

Healthy newborns (N = 75) 37 weeks or more completed gestation.

METHODS

Mothers chose time of first bath based on available time slots (n = 25 newborns in each age group). Research nurses sponge bathed the newborns in the mothers' rooms. Axillary temperature, an index of core temperature, was measured with a digital thermometer, and skin temperature, an index of body surface temperature, was measured with a thermography camera. Temperatures were taken before the bath; immediately after the bath; and 5, 30, 60, and 120 minutes after the bath. Immediately after the bath, newborns were placed in skin-to-skin care (SSC) for 60 or more minutes.

RESULTS

We found a difference (p = .0372) in axillary temperatures between the 3- and 9-hour age groups, although this difference was not clinically significant (0.18 °F [0.10 °C]). We found no statistically significant differences in skin temperatures among the three age groups. Regardless of age group, axillary and skin temperatures initially decreased and then recovered after the bath.

CONCLUSION

For up to 2 hours postbath, axillary and skin temperatures were not different between healthy newborns bathed at 3, 6, or 9 hours of age. Thermography holds promise for learning about thermoregulation, bathing, and SSC.

Neonatal Early Warning Tools for recognising and responding to clinical deterioration in neonates cared for in the maternity setting: A retrospective case-control study

BACKGROUND

All newborns are at risk of deterioration as a result of failing to make the transition to extra uterine life. Signs of deterioration can be subtle and easily missed. It has been postulated that the use of an Early Warning Tool may assist clinicians in recognising and responding to signs of deterioration earlier in neonates, thereby preventing a serious adverse event.

OBJECTIVE

To examine whether observations from a Standard Observation Tool, applied to three neonatal Early Warning Tools, would hypothetically trigger an escalation of care more frequently than actual escalation of care using the Standard Observation Tool.

DESIGN

A retrospective case-control study.

SETTING

A maternity unit in a tertiary public hospital in Australia.

METHODS

Neonates born in 2013 of greater than or equal to 34(+0) weeks gestation, admitted directly to the maternity ward from their birthing location and whose subsequent deterioration required admission to the neonatal unit, were identified as cases from databases of the study hospital. Each case was matched with three controls, inborn during the same period and who did not experience deterioration and neonatal unit admission. Clinical and physiological data recorded on a Standard Observation Tool, from time of admission to the maternity ward, for cases and controls were charted onto each of three Early Warning Tools. The primary outcome was whether the tool 'triggered an escalation of care'. Descriptive statistics (n, %, Mean and SD) were employed.

RESULTS

Cases (n=26) comprised late preterm, early term and post-term neonates and matched by gestational age group with 3 controls (n=78). Overall, the Standard Observation Tool triggered an escalation of care for 92.3% of cases compared to the Early Warning Tools; New South Wales Health 80.8%, United Kingdom Newborn Early Warning Chart 57.7% and The Australian Capital Territory Neonatal Early Warning Score 11.5%. Subgroup analysis by gestational age found differences between the tools in hypothetically triggering an escalation of care.

CONCLUSIONS

The Standard Observation Tool triggered an escalation of care more frequently than the Early Warning Tools, which may be as a result of behavioural data captured on the Standard Observation Tool and escalated, which could not be on the Early Warning Tools. Findings demonstrate that a single tool applied to all gestational age ranges may not be effective in identifying early deterioration or may over trigger an escalation of care. Further research is required into the sensitivity and specificity of Early Warning Tools in neonatal sub-populations.

Short- and Long-Term Outcomes in Very Low Birth Weight Infants with Admission Hypothermia

BACKGROUND

Neonatal hypothermia remains a common problem and is related to elevated morbidities and mortality. However, the long-term neurodevelopmental effects of admission hypothermia are still unknown. This study attempted to determine the short-term and long-term consequences of admission hypothermia in VLBW preterm infants.

STUDY DESIGN

This retrospective study measured the incidence and compared the outcomes of admission hypothermia in very low birth weight (VLBW) preterm infants in a tertiary-level neonatal intensive care unit. Infants were divided into the following groups: normothermia (36.5-37.5°C), mild hypothermia (36.0-36.4°C), moderate hypothermia (32.0-35.9°C), and severe hypothermia (< 32°C). We compared the distribution, demographic variables, short-term outcomes, and neurodevelopmental outcomes at 24 months of corrected age among groups.

RESULTS

We studied 341 infants: 79 with normothermia, 100 with mild hypothermia, 162 with moderate hypothermia, and 0 with severe hypothermia. Patients in the moderate hypothermia group had significantly lower gestational ages (28.1 wk vs. 29.7 wk, P < .02) and smaller birth weight (1004 g vs. 1187 g, P < .001) compared to patients in the normothermia group. Compared to normothermic infants, moderately hypothermic infants had significantly higher incidences of 1-min Apgar score < 7 (63.6% vs. 31.6%, P < .001), respiratory distress syndrome (RDS) (58.0% vs. 39.2%, P = .006), and mortality (18.5% vs. 5.1%, P = .005). Moderate hypothermia did not affect neurodevelopmental outcomes at 2 years' corrected age. Mild hypothermia had no effect on short-term or long-term outcomes.

CONCLUSIONS

Admission hypothermia was common in VLBW infants and correlated inversely with birth weight and gestational age. Although moderate hypothermia was associated with higher RDS and mortality rates, it may play a limited role among multifactorial causes of neurodevelopmental impairment.

Innate hypothermia after hypoxic ischaemic delivery

The focus of this review is to collate the literature on the phenomenon of impaired thermal adaptation after hypoxic ischaemic (HI) delivery often culminating in hypothermia. This phenomenon appears different in severity and duration to a spontaneous postnatal fall in temperature observed after normal delivery. The original observation and contemporary descriptions of the temperature response to HI are described and a mechanism of action is proposed that may be utilised as a novel biomarker for HI.

Importance of maintaining the newly born temperature in the normal range from delivery to admission

Over the last 50 years an increasing amount of evidence on neonatal resuscitation and stabilisation practices has led to written recommendations on all aspects of newborn care in the first few minutes of life. Much evidence for thermoregulatory management of both term and preterm infants has existed for decades and more recently research has identified new techniques to maintain normothermia in newly born infants. The use of increased environmental temperatures, skin-to-skin care, radiant warmers, plastic coverings and hats, exothermic mattresses and heated humidified gases have or are undergoing evaluation. However, despite the apparent acceptance of these techniques, a substantial number of infants continue to become hypothermic soon after delivery, leading to an increased risk of comorbidities and of death. Gaps in our knowledge remain and further research opportunities are available. However, we must also ensure that established thermoregulatory methods for which the evidence already exists are given as much emphasis as other aspects of newborn care and are implemented meticulously in all healthcare settings.

The global burden of neonatal hypothermia: systematic review of a major challenge for newborn survival

BACKGROUND

To provide evidence on the global epidemiological situation of neonatal hypothermia and to provide recommendations for future policy and research directions.

METHODS

Using PubMed as our principal electronic reference library, we searched studies for prevalence and risk factor data on neonatal hypothermia in resource-limited environments globally. Studies specifying study location, setting (hospital or community based), sample size, case definition of body temperature for hypothermia, temperature measurement method, and point estimates for hypothermia prevalence were eligible for inclusion.

RESULTS

Hypothermia is common in infants born at hospitals (prevalence range, 32% to 85%) and homes (prevalence range, 11% to 92%), even in tropical environments. The lack of thermal protection is still an underappreciated major challenge for newborn survival in developing countries. Although hypothermia is rarely a direct cause of death, it contributes to a substantial proportion of neonatal mortality globally, mostly as a comorbidity of severe neonatal infections, preterm birth, and asphyxia. Thresholds for the definition of hypothermia vary, and data on its prevalence in neonates is scarce, particularly on a community level in Africa.

CONCLUSIONS

A standardized approach to the collection and analysis of hypothermia data in existing newborn programs and studies is needed to inform policy and program planners on optimal thermal protection interventions. Thermoprotective behavior changes such as skin-to-skin care or the use of appropriate devices have not yet been scaled up globally. The introduction of simple hypothermia prevention messages and interventions into evidence-based, cost-effective packages for maternal and newborn care has promising potential to decrease the heavy global burden of newborn deaths attributable to severe infections, prematurity, and asphyxia. Because preventing and treating newborn hypothermia in health institutions and communities is relatively easy, addressing this widespread challenge might play a substantial role in reaching Millennium Development Goal 4, a reduction of child mortality.

Thermal protection of the newborn in resource-limited environments

Appropriate thermal protection of the newborn prevents hypothermia and its associated burden of morbidity and mortality. Yet, current global birth practices tend to not adequately address this challenge. Here, we discuss the pathophysiology of hypothermia in the newborn, its prevention and therapeutic options with particular attention to resource-limited environments. Newborns are equipped with sophisticated mechanisms of body temperature regulation. Neonatal thermoregulation is a critical function for newborn survival, regulated in the hypothalamus and mediated by endocrine pathways. Hypothermia activates cellular metabolism through shivering and non-shivering thermogenesis. In newborns, optimal temperature ranges are narrow and thermoregulatory mechanisms easily overwhelmed, particularly in premature and low-birth weight infants. Hyperthermia most commonly is associated with dehydration and potentially sepsis. The lack of thermal protection promptly leads to hypothermia, which is associated with detrimental metabolic and other pathophysiological processes. Simple thermal protection strategies are feasible at community and institutional levels in resource-limited environments. Appropriate interventions include skin-to-skin care, breastfeeding and protective clothing or devices. Due to poor provider training and limited awareness of the problem, appropriate thermal care of the newborn is often neglected in many settings. Education and appropriate devices might foster improved hypothermia management through mothers, birth attendants and health care workers. Integration of relatively simple thermal protection interventions into existing mother and child health programs can effectively prevent newborn hypothermia even in resource-limited environments.

Reliability of parent-measured axillary temperatures

BACKGROUND

Fever is a common symptom in children. Assessment of accuracy of parental temperature measurement is integral in determining proper medical management.

METHODS

The authors recruited 25 afebrile and 13 febrile children from outpatient sites. Participants had rectal temperatures measured by a trained study staff, followed by axillary temperature measurements by trained study staff and parent. Analysis of variance was used to compare the afebrile and febrile groups; the paired t test was used to compare parent and study personnel's axillary temperature measurements. Analysis included the statistical significance of Pearson's correlation coefficients for the various comparisons.

RESULTS

In both febrile and afebrile groups, the rectal temperatures were greater than axillary temperature measurements, but the difference was not consistent. There was a very high correlation (correlation coefficient range = .86-.96) between axillary temperature measurements performed by trained study staff and parents.

CONCLUSIONS

Parental report of axillary temperature measurement can be considered reliable.

Prevalence and risk factors for hypothermia on admission in Nigerian babies <72 h of age

BACKGROUND

Hypothermia is a major contributor to early neonatal deaths especially in the developing world. Factors which predispose babies to hypothermia need to be identified for intervention purposes.

OBJECTIVES

To determine the prevalence and risk factors for neonatal hypothermia at admission in the first 72 h of life.

METHODS

Babies hospitalized within the first 72 h of life in a Nigerian Neonatal Unit were surveyed. Data collected included age, sex, weight, place of delivery, history of breastfeeding, recent bath, oil cleansing of the skin and presence of asphyxia. Babies with skin (axillary) temperature <36.5 degrees C were considered hypothermic.

RESULTS

Of the 111 babies, 75 (67.6%) were hypothermic. The prevalence of hypothermia was high among babies aged <6 h (80.6%), preterm infants (88.9%), low-birth-weight babies (89.1%), babies with birth asphyxia (76.3%), babies without recent oiling of the skin (90.6%) and babies who had not been breastfed (79.2%). Using logistic regression, significant risk factors for early neonatal hypothermia at admission included low-birth-weight (P=0.000) and lack of breastfeeding (P=0.028).

CONCLUSION

Most of the identified risk factors are preventable. The warm chain should be strictly applied in-hospital and be taught to mothers and community health workers.

Temperature management in the delivery room

After being in a relatively stable thermoneutral uterus for the whole of pregnancy, the newborn baby enters a cooling environment and might suffer significant heat loss and hypothermia in the first minutes of life. Alternatively, the fetus might face significant hyperthermia during and immediately after delivery if the mother is febrile. Hypothermia, particularly in preterm babies, is associated with increased morbidity and mortality. Hyperthermic babies have a worse short-term outcome, and hyperthermia can be particularly detrimental in association with intrapartum asphyxia and infection. Prevention and treatment of these variations in temperature are still developing and the efficacy of some strategies remains unclear. Nevertheless, one goal in the delivery room is to maintain the newborn baby's temperature within the physiologically optimum range.

Proposed Guidelines for Skin-to-Skin Treatment of Neonatal Hypothermia

Hypothermia is not uncommon in full-term, low-risk newborns during the first days of life. Standard care for treating hypothermia often involves the separation of the mother and the newborn while the infant is placed under a warmer and observed in the nursery. Because one important role of the postpartum nurse is to promote mother-infant attachment by encouraging the mother to spend time "getting to know" her infant, this separation can be problematic. This article proposes that skin-to-skin (STS) care, also called kangaroo care, an intervention in which the unclothed, diapered infant is placed on the mother's bare chest, be used to promote thermoregulation instead of using separation and a warmer. STS care has been recognized as a way to facilitate maternal-infant attachment and promote thermoregulation. The literature review here provides an analysis of the available evidence and the author's conclusion that the research supports the use of STS care as an alternative to traditional rewarming. The evidence was graded and organized into an evidence-based practice guideline for the use of STS care in the treatment of mild hypothermia in the low-risk infant. Suggestions for further research and outcomes measurement are included.

Maternal and Newborn Outcomes Related to Maternal Warming During Cesarean Delivery

OBJECTIVE

To compare two methods of maternal warming during cesarean delivery under spinal anesthesia on maternal and newborn outcomes.

DESIGN

Randomized control trial.

SETTING

Two acute care hospitals in central Canada.

PATIENTS

62 women (32 intervention, 30 control).

INTERVENTIONS

Women received either a forced-air warming blanket (intervention) or usual care warmed cotton blankets (control).

MAIN OUTCOME MEASURES

For mothers: oral temperature, degree of shivering, thermal comfort, and pain scores. For newborns: rectal temperature at birth, 1- and 5-minute Apgar scores, and frequency of interventions for hypoglycemia within 3 hours of birth.

RESULTS

With the exception of perceived thermal comfort, women in the two groups were not significantly different in terms of oral temperature, incidence of shivering, and pain scores. Similarly, newborns in both groups were not significantly different in terms of any of the measured variables. Although newborn rectal temperature was within the normal range, mothers in both groups showed a significant decline in body temperature to the mild hypothermic range (control 36.7 +/- 0.4 degrees C to 35.9 +/- 0.5 degrees C, p < .001; intervention 36.8 +/- 0.4 degrees C to 36.1 +/- 0.4 degrees C, p < .001).

CONCLUSION

The usual treatment of supplying warmed cotton blankets remains the treatment of choice for this population.

Temperature variation in newborn babies: importance of physical contact with the mother

BACKGROUND

Hypothermia is a major cause of deterioration and death in the neonatal period. Temperature deviations are key signs of illness.

OBJECTIVE

To determine normal patterns of temperature variation in newborn babies and the influence of external factors.

METHODS

Abdominal and foot skin temperature were continuously recorded in 27 healthy full term babies during the first two days of life and related to the care situation-that is, whether the baby was with the mother or in its cot. The recordings were made using no wires to avoid interference with the care of the neonate. Ambient temperature was close to 23 degrees C during the study period.

RESULTS

Mean rectal and abdominal and foot skin temperature were lower on day 1 than day 2. The foot skin temperature was directly related to the care situation, being significantly higher when the baby was with the mother. The abdominal skin temperature was much less influenced by external factors. When the neonates were with their mothers, the mean difference between rectal temperature and abdominal skin temperature was 0.2 degrees C compared with a mean difference between rectal temperature and foot skin temperature of 1.5 degrees C, indicating a positive heat balance. In the cot the corresponding temperature differences were 0.7 degrees C and 7.5 degrees C. A temperature difference between rectal and foot skin temperature of 7-8 degrees C indicates a heat loss close to the maximum for which a neonate can compensate (about 70 W/m2).

CONCLUSION

This study emphasises the importance of close physical contact with the mothers for temperature regulation during the first few postnatal days.

The impact of newborn bathing on the prevalence of neonatal hypothermia in Uganda: a randomized, controlled trial

AIM

To elucidate the impact of bathing on the prevalence of hypothermia among newborn babies exposed to the skin-to-skin (STS) care technique before and after bathing.

METHODS

Non-asphyxiated newborns after vaginal delivery (n = 249) in a Ugandan referral hospital were consecutively enrolled and randomized either to bathing at 60 min postpartum (n = 126) or no bathing (n = 123). All mothers practised skin-to-skin care of their newborns. Four rectal and tympanic registrations of newborn temperatures were carried out in both groups directly after drying at birth, and at 60, 70 and 90 min postpartum.

RESULTS

Bathing of newborns in the first hour after delivery resulted in a significantly increased prevalence of hypothermia, defined as temperature <36.5 degrees C, at 70 and at 90 min postpartum despite the use of warmed water and the application of the STS method. There was no neonatal mortality. Aside from the bathing procedure, no background factor potentially predisposing the newborns to hypothermia was identified.

CONCLUSION

Bathing newborn babies shortly after birth increased the risk of hypothermia despite the use of warm water and STS care for thermal protection of the newborn.

Change in the body temperature of healthy term infant over the first 72 hours of life

OBJECTIVE

To determine the range of body temperature in a group of healthy Chinese term neonates over the first 72 hours of life and to assess the influence of body weight, gestational age and route of delivery.

METHOD

All 200 consecutive cases of neonates delivered at our hospital from March to August 2001 were included in this retrospective study. Temperatures were measured immediately after delivery, after 30 minutes, 1 hour, 2 hours, 8 hours and 15 hours and on the 2nd and 3rd day. Axillary temperatures ranging from 36.5 degrees C to 37 degrees C were regarded as normal. No cases of maternal fever or systemic infection of the newborns were discovered. All infants were discharged in good general condition.

RESULTS

The mean rectal temperature at birth was 37.19 degrees C. The lowest average temperature was reached at 1 hour after delivery (36.54 degrees C) with a significant difference between natural delivery (36.48 degrees C) and section (36.59 degrees C) (P<0.05). Temperature subsequently rose to 36.70 degrees C at 8 hours and 36.78 degrees C at 15 hours (P<0.05). Hypothermia was seen in 51.8% and hypothermia in 42.5% of the patients. On the 3rd day after delivery, 96% of all temperatures were in the normal range. A significant relation was found between hypothermia and both low birth weight (P<0.001) and low gestational age (P<0.05).

CONCLUSION

The reference range presently used did not include all physiological temperatures in the first 72 hours of life. Considering other factors, such as birth weight, route of delivery, gestational age and body temperature on the 2nd and 3rd day of life, may help to correctly assess the significance of temperatures beyond the reference range.