Hypothermia in Preterm Newborns: Impact on Survival

Thermoregulation for very preterm infants in the delivery room: a narrative review

Abnormal temperature in preterm infants is associated with increased morbidity and mortality. Infants born prematurely are at risk of abnormal temperature immediately after birth in the delivery room (DR). The World Health Organization (WHO) recommends that the temperature of newly born infants is maintained between 36.5-37.5oC after birth. When caring for very preterm infants, the International Liaison Committee on Resuscitation (ILCOR) recommends using a combination of interventions to prevent heat loss. While hypothermia remains prevalent, efforts to prevent it have increased the incidence of hyperthermia, which may also be harmful. Delayed cord clamping (DCC) for preterm infants has been recommended by ILCOR since 2015. Little is known about the effect of timing of DCC on temperature, nor have there been specific recommendations for thermal care before DCC. This review article focuses on the current evidence and recommendations for thermal care in the DR, and considers thermoregulation in the context of emerging interventions and future research directions. IMPACT: Abnormal temperature is common amongst very preterm infants after birth, and is an independent risk factor for mortality. The current guidelines recommend a combination of interventions to prevent heat loss after birth. Despite this, abnormal temperature is still a problem, across all climates and economies. New and emerging delivery room practice (i.e., delayed cord clamping, mobile resuscitation trolleys, early skin to skin care) may have an effect on infant temperature. This article reviews the current evidence and recommendations, and considers future research directions.

Preclinical validation of NeoWarm, a low-cost infant warmer and carrier device, to ameliorate induced hypothermia in newborn piglets as models for human neonates

Introduction

Approximately 1.5 million neonatal deaths occur among premature and small (low birthweight or small-for gestational age) neonates annually, with a disproportionate amount of this mortality occurring in low- and middle-income countries (LMICs). Hypothermia, the inability of newborns to regulate their body temperature, is common among prematurely born and small babies, and often underlies high rates of mortality in this population. In high-resource settings, incubators and radiant warmers are the gold standard for hypothermia, but this equipment is often scarce in LMICs. Kangaroo Mother Care/Skin-to-skin care (KMC/STS) is an evidence-based intervention that has been targeted for scale-up among premature and small neonates. However, KMC/STS requires hours of daily contact between a neonate and an able adult caregiver, leaving little time for the caregiver to care for themselves. To address this, we created a novel self-warming biomedical device, NeoWarm, to augment KMC/STS. The present study aimed to validate the safety and efficacy of NeoWarm.

Methods

Sixteen, 0-to-5-day-old piglets were used as an animal model due to similarities in their thermoregulatory capabilities, circulatory systems, and approximate skin composition to human neonates. The piglets were placed in an engineered cooling box to drop their core temperature below 36.5°C, the World Health Organizations definition of hypothermia for human neonates. The piglets were then warmed in NeoWarm (n = 6) or placed in the ambient 17.8°C ± 0.6°C lab environment (n = 5) as a control to assess the efficacy of NeoWarm in regulating their core body temperature.

Results

All 6 piglets placed in NeoWarm recovered from hypothermia, while none of the 5 piglets in the ambient environment recovered. The piglets warmed in NeoWarm reached a significantly higher core body temperature (39.2°C ± 0.4°C, n = 6) than the piglets that were warmed in the ambient environment (37.9°C ± 0.4°C, n = 5) (p < 0.001). No piglet in the NeoWarm group suffered signs of burns or skin abrasions.

Discussion

Our results in this pilot study indicate that NeoWarm can safely and effectively warm hypothermic piglets to a normal core body temperature and, with additional validation, shows promise for potential use among human premature and small neonates.

Hypothermia amongst neonatal admissions in Kenya: a retrospective cohort study assessing prevalence, trends, associated factors, and its relationship with all-cause neonatal mortality

Background

Reports on hypothermia from high-burden countries like Kenya amongst sick newborns often include few centers or relatively small sample sizes.

Objectives

This study endeavored to describe: (i) the burden of hypothermia on admission across 21 newborn units in Kenya, (ii) any trend in prevalence of hypothermia over time, (iii) factors associated with hypothermia at admission, and (iv) hypothermia's association with inpatient neonatal mortality.

Methods

A retrospective cohort study was conducted from January 2020 to March 2023, focusing on small and sick newborns admitted in 21 NBUs. The primary and secondary outcome measures were the prevalence of hypothermia at admission and mortality during the index admission, respectively. An ordinal logistic regression model was used to estimate the relationship between selected factors and the outcomes cold stress (36.0°C-36.4°C) and hypothermia (<36.0°C). Factors associated with neonatal mortality, including hypothermia defined as body temperature below 36.0°C, were also explored using logistic regression.

Results

A total of 58,804 newborns from newborn units in 21 study hospitals were included in the analysis. Out of these, 47,999 (82%) had their admission temperature recorded and 8,391 (17.5%) had hypothermia. Hypothermia prevalence decreased over the study period while admission temperature documentation increased. Significant associations were found between low birthweight and very low (0-3) APGAR scores with hypothermia at admission. Odds of hypothermia reduced as ambient temperature and month of participation in the Clinical Information Network (a collaborative learning health platform for healthcare improvement) increased. Hypothermia at admission was associated with 35% (OR 1.35, 95% CI 1.22, 1.50) increase in odds of neonatal inpatient death.

Conclusions

A substantial proportion of newborns are admitted with hypothermia, indicating a breakdown in warm chain protocols after birth and intra-hospital transport that increases odds of mortality. Urgent implementation of rigorous warm chain protocols, particularly for low-birth-weight babies, is crucial to protect these vulnerable newborns from the detrimental effects of hypothermia.

The Role of Brown Adipose Tissue and Energy Metabolism in Mammalian Thermoregulation during the Perinatal Period

Hypothermia is one of the most common causes of mortality in neonates, and it could be developed after birth because the uterus temperature is more elevated than the extrauterine temperature. Neonates use diverse mechanisms to thermoregulate, such as shivering and non-shivering thermogenesis. These strategies can be more efficient in some species, but not in others, i.e., altricials, which have the greatest difficulty with achieving thermoneutrality. In addition, there are anatomical and neurological differences in mammals, which may present different distributions and amounts of brown fat. This article aims to discuss the neuromodulation mechanisms of thermoregulation and the importance of brown fat in the thermogenesis of newborn mammals, emphasizing the analysis of the biochemical, physiological, and genetic factors that determine the distribution, amount, and efficiency of this energy resource in newborns of different species. It has been concluded that is vital to understand and minimize hypothermia causes in newborns, which is one of the main causes of mortality in neonates. This would be beneficial for both animals and producers.

Neonatal warming devices: What can be recommended for low-resource settings when skin-to-skin care is not feasible?

Hypothermia occurs frequently among clinically unstable neonates who are not suitable to place in skin-to-skin care. This study aims to explore the existing evidence on the effectiveness, usability, and affordability of neonatal warming devices when skin-to-skin care is not feasible in low-resource settings. To explore existing data, we searched for (1) systematic reviews as well as randomised and quasi-randomised controlled trials comparing the effectiveness of radiant warmers, conductive warmers, or incubators among neonates, (2) neonatal thermal care guidelines for the use of warming devices in low-resource settings and (3) technical specification and resource requirement of warming devices which are available in the market and certified medical device by the US Food and Drug Administration or with a CE marking. Seven studies met the inclusion criteria, two were systematic reviews comparing radiant warmers vs. incubators and heated water-filled mattresses vs. incubators, and five were randomised controlled trials comparing conductive thermal mattresses with phase-change materials vs. radiant warmers and low-cost cardboard incubator vs. standard incubator. There was no significant difference in effectiveness between devices except radiant warmers caused a statistically significant increase in insensible water loss. Seven guidelines covering the use of neonatal warming devices show no consensus about the choice of warming methods for clinically unstable neonates. The main warming devices currently available and intended for low-resource settings are radiant warmers, incubators, and conductive warmers with advantages and limitations in terms of characteristics and resource requirements. Some devices require consumables which need to be considered when making a purchase decision. As effectiveness is comparable between devices, specific requirements according to patients' characteristics, technical specification, and context suitability must play a primary role in the selection and purchasing decision of warming devices. In the delivery room, a radiant warmer allows fast access during a short period and will benefit numerous neonates. In the neonatal unit, warming mattresses are low-cost, effective, and low-electricity consumption devices. Finally, incubators are required for very premature infants to control insensible water losses, mainly during the first one to two weeks of life, mostly in referral centres.

Intraoperative hypothermia in the neonate population: risk factors, outcomes, and typical patterns

The risk factors, outcomes, and typical patterns of intraoperative hypothermia were studied in neonates to better guide the application of insulation measures in the operating room. This retrospective study enrolled 401 neonates undergoing surgery under general anaesthesia with tracheal intubation, including abdominal surgery, thoracic surgery, brain surgery, and others. The study collected basic characteristics, such as age, sex, weight, birth weight, gestational week, primary diagnosis and American Society of Anaesthesiologists (ASA) grade. Perioperative data included preoperative body temperature, length of hospital stay, length of intensive care unit (ICU) stay, intubation time, postoperative bleeding, postoperative pneumonia, postoperative death, and total cost of hospitalization. Intraoperative data included surgical procedures, anaesthesia duration, operation duration, blood transfusion, fluid or albumin infusion, and application of vasoactive drugs. The incidence of intraoperative hypothermia (< 36 °C) was 81.05%. Compared to normothermic patients, gestational week (OR 0.717; 95% CI 0.577-0.890; P = 0.003), preoperative temperature (OR 0.228; 95% CI 0.091-0.571; P = 0.002), duration of anaesthesia (OR 1.052; 95% CI 1.027-1.077; P < 0.001), and type of surgery (OR 2.725; 95% CI 1.292-5.747; P = 0.008) were associated with the risk of intraoperative hypothermia. Patients with hypothermia had longer length of ICU stay (P = 0.001), longer length of hospital stay (P < 0.001), and higher hospital costs (P < 0.001). But there were no association between clinical outcomes and intraoperative hypothermia in the multivariable regression adjusted analysis. The lowest point of intraoperative body temperature was approximately 1 h 30 min. Then, the body temperature of patients successively entered a short plateau phase and a period of slow ascent. The greatest decrease in body temperatures occurred in preterm babies and neonates with preoperative hypothermia. The lowest core temperatures that occurred in neonates with preoperative hypothermia was lower than 35 °C. This study shows that there is a high incidence of intraoperative hypothermia in the neonate population. The intraoperative body temperature of neonates dropped to the lowest point in 1-1.5 h. The greatest decrease in core temperatures occurred in preterm babies and neonates with lower preoperative temperature.

Risk factors for neonatal hypothermia at Arba Minch General Hospital, Ethiopia

BACKGROUND

The first few minutes after birth are the most dangerous for the survival of an infant. Babies in neonatal intensive care units are either under heated or overheated, and hypothermic infants remain hypothermic or develop a fever. As a result, special attention must be paid to monitoring and maintaining the time of recovery from hypothermia states. Despite numerous studies, only a few have examined the transition from neonatal hypothermia and associated risk factors in depth.

METHOD

A retrospective observational study was conducted to track axillary temperatures taken at the time of neonatal intensive care unit admission, which were then tracked every 30 minutes until the newborn's temperature stabilized. All hypothermic neonates admitted to the neonatal intensive care unit between January 2018 and December 2020 was included in the study. Temperature data were available at birth and within the first three hours of admission for 391 eligible hypothermic neonates. The effect of factors on the transition rate in different states of hypothermia was estimated using a multi-state Markov model.

RESULT

The likelihood of progressing from mild to severe hypothermia was 5%, while the likelihood of progressing to normal was 34%. The average time spent in a severe hypothermia state was 48, 35, and 24 minutes for three different levels of birth weight, and 53, 41, and 31 minutes for low, moderate, and normal Apgar scores, respectively. Furthermore, the mean sojourn time in a severe hypothermia state was 48, 39, and 31 minutes for three different levels of high, normal, and low pulse rate, respectively.

CONCLUSION

For hypothermic survivors within the first three hours of life, very low birth weight, low Apgar, and high pulse rate had the strongest association with hypothermia and took the longest time to improve/recover. As a result, there is an urgent need to train all levels of staff dealing with maintaining the time of recovery from neonatal hypothermia.

Escalating the limit of median survival time and predictors of mortality among preterm neonates in Northwest Ethiopia, 2021: a 1-year prospective follow-up study

OBJECTIVES

To examine the survival rate and predictors of mortality among preterm neonates in the neonatal intensive care unit at South Gondar public hospitals, 2021.

DESIGN

Prospective follow-up study.

SETTING

South Gondar public hospitals, Northwest, Ethiopia.

PARTICIPANTS

We recruited 283 preterm neonates who were admitted at neonatal intensive care unit at selected hospitals from 15 February 2020 to 22 January 2021.

OUTCOME MEASURES

The primary outcome measure of this study was the survival rate of preterm neonates in the neonatal intensive care unit. Moreover, the study assessed the predictors for the occurrence of mortality by the Cox-proportional hazard model. Data were entered into Epi data V.4.2 and exported to Stata V.14 statistical software for analysis. The log-rank test determines the survival difference between predictor variables.

RESULTS

A total of 283 preterm neonates, 61 died during the follow-up. Born from antepartum haemorrhage mother (adjusted HR (AHR)=2.2 (95% CI 1.10 to 4.37)), being small weight for gestational age (AHR=4.6 (95% CI 2.22 to 9.53)), not having kangaroo mother care practice initiated (AHR=2.7 (95% CI 1.39 to 7.74)), hypothermia (AHR=4.0 (95% CI 1.96 to 8.30)) and perinatal asphyxia (AHR=3.9 (95% CI 1.97 to 7.94)) were significant predictors of preterm neonate mortality.

CONCLUSION

In this study, the preterm neonates survival rate (78.4%) and the median survival time (21 days) were found to be low. Preventing and managing the predictors, including an antepartum haemorrhagic mother, small weight for gestational age, hypothermia and prenatal asphyxia, is crucial. In addition, more emphasis should be placed on initiating universal kangaroo mother care practice soon after birth to increase the survival of preterm neonates.

Causes of and Modifiable Factors Contributing to Neonatal Deaths at Dora Nginza Hospital in the Eastern Cape, South Africa

Dora Nginza Hospital (DNH) has a neonatal mortality rate higher than global and national averages. In 2015 to 2016 the neonatal mortality rate in South Africa was 18.1/1000 live births compared with 31.3/1000 live births at DNH. A retrospective study was conducted including neonates less than 28 days of life with a birth weight ≥500 g that demised in DNH neonatal unit. The NMR for the study period was 17.7/1000 live births. There were 101 (70.6%) early and 42 (29.4%) late neonatal deaths. Causes of death included infection (n = 47; 32.9%), immaturity-related (n = 42; 29.4%), congenital abnormalities (n = 26; 18.2%), hypoxia (n = 24; 16.8%) and other (n = 4; 2.8%). There were significant associations between cause of death and administrative-related factors (P < .01), health-personnel related factors (P < .001) and patient-related factors (P = .01). Key strategies to be implemented include improving infection prevention and control, appropriate resource allocation, improved attendance and quality of antenatal care, ongoing skills training, and interventions to maintain normothermia.

Using a Plastic Drape to Reduce Hypothermia in Premature Neonates During Peripherally Inserted Central Catheter Placement

BACKGROUND

Premature neonates require assisted heating devices for thermoregulation in the neonatal intensive care unit (NICU). Traditional use of a cloth blanket and cloth towels during peripherally inserted central catheter (PICC) placement may hinder heat transfer from the assisted heating mechanisms, increasing the risk for neonatal hypothermia.

PURPOSE

This quality improvement project's goal was to reduce the hypothermia rate in very low birth-weight (VLBW) neonates by replacing cloth blanket/towels with a plastic drape during PICC placement.

METHODS

The FOCUS-PDSA method was used to implement the intervention (plastic drape) over 3 months, during 58 PICC procedures in a level 3 NICU. A pre-/posttest design was used to evaluate the impact of the intervention on hypothermia rates compared with a baseline cloth group and a concurrent cloth cohort.

RESULTS

After the 3-month implementation period, the hypothermia rate for the intervention group was lower than that for the baseline cloth group (5.2% and 11.3%, respectively), but this difference was not statistically significant. Post-PICC hypothermia rates were significantly lower for the intervention group than for the concurrent cloth cohort (P = .004).

IMPLICATIONS FOR PRACTICE

Preliminary evidence demonstrated the plastic drape reduced the hypothermia rate in the NICU for VLBW neonates during PICC placement compared with cloth blanket/towels. A plastic drape shows promise in improving nursing practice by providing improved thermoregulation for premature neonates during PICC placement.

IMPLICATIONS FOR RESEARCH

Further research is recommended to replicate findings with larger samples of PICC insertions, using a plastic drape in the operating room and other NICU procedures.

Perinatal factors associated with admission to neonatal intensive care unit following cesarean delivery in Kano, northern Nigeria

OBJECTIVES

Cesarean section is the most common obstetric surgical procedure, with associated risks for adverse neonatal outcomes. The interplay of perinatal factors associated with neonatal admissions following cesarean delivery remains poorly understood in developing countries. We examined how perinatal and facility-based factors affect Neonatal Intensive Care Unit (NICU) admission after cesarean delivery in northern Nigeria.

METHODS

A prospective cohort study involving 200 women undergoing cesarean section were consecutively enrolled with subsequent follow-up of their infants in the post-natal period. Data were abstracted from the medical record using an interviewer-administered questionnaire. The primary outcomes were NICU admission and intrauterine or early neonatal deaths. Binary logistic regression modelling was used to identify variables independently associated with the outcomes.

RESULTS

Over the study period (six months), there were 200 cesarean sections. A total of 30 (15.0%) neonates were admitted into the NICU following the procedure. No stillbirths or early neonatal deaths were recorded. NICU admission was associated with gestational age (preterm vs. term [adjusted odds ratio, aOR: 18.9, 95% confidence interval (CI): 4.0-90.4]), birth weight (small vs. appropriate [aOR: 6.7, 95% CI 1.9-22.7] and large vs. appropriate birth weight [aOR: 20.3, 95% CI 2.9-143.7]) and the number of indications for cesarean section (≥2 vs. one [aOR: 0.2, 95% 0.1-0.8]).

CONCLUSIONS

Prematurity, small and large for gestational age neonates; and indications for cesarean section were associated with increased likelihood of neonatal admission following cesarean delivery. These findings could inform ongoing quality enhancement initiatives to improve NICU admission outcomes at the study site, and other similar settings.

2.5 Million Annual Deaths-Are Neonates in Low- and Middle-Income Countries Too Small to Be Seen? A Bottom-Up Overview on Neonatal Morbi-Mortality

(1) Background: Every year, 2.5 million neonates die, mostly in low- and middle-income countries (LMIC), in total disregard of their fundamental human rights. Many of these deaths are preventable. For decades, the leading causes of neonatal mortality (prematurity, perinatal hypoxia, and infection) have been known, so why does neonatal mortality fail to diminish effectively? A bottom-up understanding of neonatal morbi-mortality and neonatal rights is essential to achieve adequate progress, and so is increased visibility. (2) Methods: We performed an overview on the leading causes of neonatal morbi-mortality and analyzed the key interventions to reduce it with a bottom-up approach: from the clinician in the field to the policy maker. (3) Results and Conclusions: Overall, more than half of neonatal deaths in LMIC are avoidable through established and well-known cost-effective interventions, good quality antenatal and intrapartum care, neonatal resuscitation, thermal care, nasal CPAP, infection control and prevention, and antibiotic stewardship. Implementing these requires education and training, particularly at the bottom of the healthcare pyramid, and advocacy at the highest levels of government for health policies supporting better newborn care. Moreover, to plan and follow interventions, better-quality data are paramount. For healthcare developments and improvement, neonates must be acknowledged as humans entitled to rights and freedoms, as stipulated by international law. Most importantly, they deserve more respectful care.