A comparison of cooling methods used in therapeutic hypothermia for perinatal asphyxia

Physiological and behavioral stability of newborns on therapeutic hypothermia for hypoxic-ischemic encephalopathy during parental holding

BACKGROUND

Physical separation contributes to parental trauma and poor bonding in the context of therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy (HIE). Parental holding (PH) may improve parents' experience. We aim to determine the physiological and behavioral stability of the newborn held by the parents during TH.

METHODS

Observational, prospective, single-center study which included 30 newborns with mean gestational age of 39 (1.8) weeks and mean birth weight 3165 (508) g, with HIE treated by TH, whom parents wanted to hold. All infants were mechanically ventilated and received sedation-analgesia. Main outcome was change in body temperature (> 34°C or < 33 °C) during PH. Secondary outcomes were change in vital signs and behavior (comfort/pain scores) during PH. Parental and nurses' opinions were assessed by a self-reporting questionnaire with a 10-point Likert scale.

RESULTS

We found no significant changes in temperature, other vital signs or in infants' COMFORT-B score during parental holding. Responses to self-reporting questionnaires completed by parents and nurses showed a high level of overall effectiveness and satisfaction with PH.

CONCLUSION

Parents holding newborns undergoing therapeutic hypothermia for hypoxic-ischemic encephalopathy was safe for the newborn without causing discomfort. It was also beneficial for the parents and supported by the healthcare team.

IMPACT

Parents holding newborns undergoing therapeutic hypothermia for Hypoxic Ischemic Encephalopathy was feasible without causing discomfort. It was also beneficial for the parents and supported by the healthcare team. Infants' temperature or other vital signs did not change during parental holding, which was found very satisfactory by parents and healthcare givers, showing that parental holding is feasible. This study promotes further dissemination of parental holding, which may limit the detrimental effect of physical separation for parents of newborns undergoing therapeutic hypothermia.

Quantitative Electroencephalography in Term Neonates During the Early Postnatal Period Across Various Sleep States

Background

Neonatal sleep is pivotal for their growth and development, yet manual interpretation of raw images is time-consuming and labor-intensive. Quantitative Electroencephalography (QEEG) presents significant advantages in terms of objectivity and convenience for investigating neonatal sleep patterns. However, research on the sleep patterns of healthy neonates remains scarce. This study aims to identify QEEG markers that distinguish between different neonatal sleep cycles and analyze QEEG alterations across various sleep stages in relation to postmenstrual age.

Methods

From September 2023 to February 2024, full-term neonates admitted to the neonatology department at the Obstetrics and Gynecology Hospital of Fudan University were enrolled in this study. Electroencephalographic (EEG) recordings were obtained from neonates aged 37-42 weeks, within 1-7 days post-birth. The ROC curve was employed to evaluate QEEG features related to amplitude, range EEG (rEEG), spectral density, and connectivity across different sleep stages. Furthermore, regression analyses were performed to investigate the association between these QEEG characteristics and postmenstrual age.

Results

The alpha frequency band's spectral_diff_F3 emerged as the most potent discriminator between active sleep (AS) and quiet sleep (QS). In distinguishing AS from wakefulness (W), the theta frequency's spectral_diff_C4 was the most effective, whereas the delta frequency's spectral_diff_P4 excelled in differentiating QS from W. During AS and QS phases, there was a notable increase in entropy within the delta frequency band across all monitored brain regions and in the spectral relative power within the theta frequency band, correlating with postmenstrual age (PMA).

Conclusion

Spectral difference showcases the highest discriminative capability across awake and various sleep states. The observed patterns of neonatal QEEG alterations in relation to PMA are consistent with the maturation of neonatal sleep, offering insights into the prediction and evaluation of brain development outcomes.

Is Selective Head Cooling Combined with Whole-Body Cooling the Most Effective Hypothermia Method for Neonatal Hypoxic-Ischemic Encephalopathy?

This study aimed to compare combined hypothermia (CH) to the 2 classical therapeutic hypothermia (TH) methods selective head cooling (SHC) and whole-body cooling (WBC). This retrospective cohort study included neonates who underwent CH, SHC, and WBC between 2012 and 2020. Mean rectal temperature was maintained at 33.5 ± 0.5°C by cooling the head and the body in the CH group, at 34.5 ± 0.5°C by cooling the head in the SHC group, and at 33.5 ± 0.5°C by cooling the body in the WBC group. The groups were compared in terms of side effects, magnetic resonance imaging (MRI) scores, and status at discharge. The study included 60 neonates in the CH group, 112 in the WBC group, and 27 in the SHC group. There was no significant difference in side effects between the groups (p > 0.05). There was no significant difference in brain MRI scores between the groups (p > 0.05); however, gray matter, white matter, and total MRI scores in the CH group were lower than in the WBC group. Duration of hospitalization was shorter in the CH group than in the other two groups (p = 0.022). CH was not associated with more side effects than the two classical TH methods. In addition, some of these findings suggest that CH might result in better clinical outcome than the two classical TH methods.

Management of comfort and sedation in neonates with neonatal encephalopathy treated with therapeutic hypothermia

Ensuring comfort for neonates undergoing therapeutic hypothermia (TH) after neonatal encephalopathy (NE) exemplifies a vital facet of neonatal neurocritical care. Physiologic markers of stress are frequently present in these neonates. Non-pharmacologic comfort measures form the foundation of care, benefitting both the neonate and parents. Pharmacological sedatives may also be indicated, yet have the potential to both mitigate and intensify the neurotoxicity of a hypoxic-ischemic insult. Morphine represents current standard of care with a history of utilization and extensive pharmacokinetic data to guide safe and effective dosing. Dexmedetomidine, as an alternative to morphine, has several appealing characteristics, including neuroprotective effects in animal models; robust pharmacokinetic studies in neonates with NE treated with TH are required to ensure a safe and effective standard dosing approach. Future studies in neonates treated with TH must address comfort, adverse events, and long-term outcomes in the context of specific sedation practices.

Meta-analysis comparing temperature on arrival at the referral hospital of newborns with hypoxic ischemic encephalopathy cooled with a servo-controlled device versus no device during transport

BACKGROUND

Therapeutic hypothermia reduces mortality and neurological injury for neonates with hypoxic ischemic encephalopathy (HIE). The aim of this meta-analysis is to evaluate use of servo-controlled devices during transport to the referral hospital.

METHODS

PubMed and Medline (Ovid) searches were used to identify studies comparing HIE patients' temperatures on arrival at the referral hospital for those cooled with servo-controlled devices versus no device during transport. Random effects models were used to conduct a meta-analysis comparing the two groups' proportion of patients arriving in the target temperature range as well as the mean and variability in body temperature on arrival. Studies' level of evidence and risk of bias were also assessed.

RESULTS

Eight published studies with total of 573 patients met the inclusion criteria, with a "B" grade of recommendation overall. A significantly higher proportion of infants cooled with a servo-controlled device arrived in the target temperature range (pooled relative risk = 2.47, 95% confidence interval: 1.46-4.17, p < 0.001). The arrival temperature in the device cooled group was on average 0.82°C lower (95% CI: 0.29-1.35°C, p = 0.002) with an 82% lower temperature variance.

CONCLUSIONS

Although the predominance of observational studies and presence of some risks of bias somewhat limits the strength of recommendation, the existing research consistently indicates that using a servo-controlled device during transport of neonates with HIE increases the probability of arriving at the referral hospital in the target temperature range, with a lower body temperature and less variability. Future research is needed to investigate differences in mortality and neurological impairment.

School-age outcomes of children without cerebral palsy cooled for neonatal hypoxic-ischaemic encephalopathy in 2008-2010

OBJECTIVE

Since therapeutic hypothermia became standard care for neonatal hypoxic-ischaemic encephalopathy (HIE), even fewer infants die or have disability at 18-month assessment than in the clinical trials. However, longer term follow-up of apparently unimpaired children is lacking. We investigated the cognitive, motor and behavioural performances of survivors without cerebral palsy (CP) cooled for HIE, in comparison with matched non-HIE control children at 6-8 years.

DESIGN

Case-control study.

PARTICIPANTS

29 case children without CP, cooled in 2008-2010 and 20 age-matched, sex-matched and social class-matched term-born controls.

MEASURES

Wechsler Intelligence Scales for Children, Fourth UK Edition, Movement Assessment Battery for Children, Second Edition (MABC-2) and Strengths and Difficulties Questionnaire.

RESULTS

Cases compared with controls had significantly lower mean (SD) full-scale IQ (91 [10.37]vs105[13.41]; mean difference (MD): -13.62, 95% CI -20.53 to -6.71) and total MABC-2 scores (7.9 [3.26]vs10.2[2.86]; MD: -2.12, 95% CI -3.93 to -0.3). Mean differences were significant between cases and controls for verbal comprehension (-8.8, 95% CI -14.25 to -3.34), perceptual reasoning (-13.9, 95% CI-20.78 to -7.09), working memory (-8.2, 95% CI-16.29 to -0.17), processing speed (-11.6, 95% CI-20.69 to -2.47), aiming and catching (-1.6, 95% CI-3.26 to -0.10) and manual dexterity (-2.8, 95% CI-4.64 to -0.85). The case group reported significantly higher median (IQR) total (12 [6.5-13.5] vs 6 [2.25-10], p=0.005) and emotional behavioural difficulties (2 [1-4.5] vs 0.5 [0-2.75], p=0.03) and more case children needed extra support in school (34%vs5%, p=0.02) than the control group.

CONCLUSIONS

School-age children without CP cooled for HIE still have reduced cognitive and motor performance and more emotional difficulties than their peers, strongly supporting the need for school-age assessments.

Selective head cooling and whole body cooling as neuroprotective agents in severe perinatal asphyxia

INTRODUCTION

The possibility that hypothermia has a therapeutic role during or after resuscitation from severe perinatal asphyxia has been a longstanding focus of research. Studies designed around this fact have shown that moderate cerebral hypothermia, initiated as early as possible, has been associated with potent, long-lasting neuroprotection in perinatal patients.

OBJECTIVES

To review the benefits of hypothermia in improving cellular function, based on the cellular characteristics of hypoxic-ischemic cerebral injury and compare the results of two different methods of cooling the brain parenchyma.

METHODS

Medline, Lilacs, Scielo, and PubMed were searched for articles registered between 1990 and 2019 in Portuguese and English, focused on trials comparing the safety and effectiveness of total body cooling with selective head cooling with HIE.

RESULTS

We found that full-body cooling provides homogenous cooling to all brain structures, including the peripheral and central regions of the brain. Selective head cooling provides a more extensive cooling to the cortical region of the brain than to the central structures.

CONCLUSIONS

Both methods demonstrated to have neuroprotective properties, although full-body cooling provides a broader area of protection. Recently, head cooling combined with some body cooling has been applied, which is the most promising approach. The challenge for the future is to find ways of improving the effectiveness of the treatment.

Neonatal Encephalopathy: Current Management and Future Trends

It is well-documented in the literature that infants who suffer from hypoxic ischemic encephalopathy are at high risk for neurologic sequelae or even death. With the addition of therapeutic hypothermia into the treatment regimen for neonatal hypoxic ischemic encephalopathy, newborns afflicted with hypoxic ischemic encephalopathy were given the opportunity for a better outcome. Questions linger as to the most optimal treatment strategy of therapeutic hypothermia for these newborns. The goal of this article is to discuss current management strategies, as well as future trends, for infants with hypoxic ischemic encephalopathy.

Impact of Education on Hypothermia Delivery during Neonatal Transport

BACKGROUND

Moderate therapeutic hypothermia (TH) initiated within 6 h of life reduces adverse neurodevelopmental outcomes in infants after perinatal hypoxic ischaemic insult. For infants born in non-tertiary centres, TH may be initiated manually en route to a neonatal intensive care unit (NICU). However, both over- and undercooling is reported with this strategy, precluding some infants from the benefits of TH.

OBJECTIVES

To evaluate the impact of a region-wide educational programme on the safety and efficacy of manual cooling administered by the Wellington Neonatal Transport Service (NeTS).

METHODS

Clinical records of infants with hypoxic ischaemic encephalopathy (HIE) retrieved by the Wellington NeTS for TH between January 2012 and June 2017 were reviewed retrospectively. Temperature outcomes of infants retrieved before and after the education programme were compared.

RESULTS

A total of 101 infants were cooled manually by Wellington NeTS for TH during the study period. Education and training significantly reduced the rate of overcooling to ≤32.0°C (4/43 [9%] vs. 0/58, p = 0.02). However, there was no difference in the proportion of infants who achieved target rectal temperature within 6 h of life (29/43 [65%] vs. 35/58 [60%], p = 0.57).

CONCLUSIONS

Introduction of a region-wide educational programme may have improved the safety of manual cooling during neonatal transport but it had a negligible impact on its efficacy. The use of servo-controlled cooling during transport should therefore be considered to improve access to the optimal neuroprotective benefits of TH for outborn infants with HIE.

Perinatal asphyxia in a rural Nigerian hospital: Incidence and determinants of early outcome

BACKGROUND

Perinatal asphyxia is an important cause of morbidity and mortality in the neonatal period, accounting for 20-30% of neonatal mortality. A substantial proportion (estimated at 26%) of the 1 million annual intrapartum stillbirths result from asphyxia. Probably higher than the mortality is the plethora of morbidity associated with asphyxia, especially long term neuro-developmental problems including cerebral palsy.The real burden of perinatal asphyxia is difficult to establish because of paucity of information from the rural communities where the majority of neonatal morbidity and deaths occur. Extended Apgar scores and HIE grade have been identified as predictive tools in prognosticating asphyxia, however HIE staging require a certain level of medical expertise which is not widely available.

AIM

To determine the incidence of asphyxia, the mortality rate and factors associated with mortality in Irrua Specialist Hospital.

METHOD

It was a descriptive, retrospective study of neonates admitted into the special care baby unit (SCBU) between October 2013 and September 2014 with diagnosis of perinatal asphyxia. Data was obtained from babies' and mother's case notes. The outcome was classified as survived or died.

RESULTS

Perinatal asphyxia accounted for 45 out of 347 (13%) of admissions within the review period. The mean gestational age and birth weight of the subjects were 39.2±2.2 weeks and 3020±520 grams respectively. The mortality rate was 31.1% and the factors significantly associated with mortality include lack of antenatal care and HIE stage III.

CONCLUSION

The burden of perinatal asphyxia in Irrua Specialist Hospital is comparable to figures from similar settings in the developing world. Lack of antenatal care and HIE stage III are associated with mortality. Continuous efforts should be made to improve the uptake of antenatal care and high risk pregnancies should be delivered in centres with facilities for neonatal care.

Body Temperature, Heart Rate, and Short-Term Outcome of Cooled Infants

Therapeutic hypothermia following neonatal encephalopathy is neuroprotective. However, approximately one in two cooled infants still die or develop permanent neurological impairments. Further understanding of variables associated with the effectiveness of cooling is important to improve the therapeutic regimen. To identify clinical factors associated with short-term outcomes of cooled infants, clinical data of 509 cooled infants registered to the Baby Cooling Registry of Japan between 2012 and 2014 were evaluated. Independent variables of death during the initial hospitalization and survival discharge from the cooling hospital at ≤28 days of life were assessed. Death was associated with higher Thompson scores at admission (p < 0.001); higher heart rates after 3-72 hours of cooling (p < 0.001); and higher body temperature after 24 hours of cooling (p = 0.002). Survival discharge was associated with higher 10 minutes Apgar scores (p < 0.001); higher blood pH and base excess (both p < 0.001); lower Thompson scores (at admission and after 24 hours of cooling; both p < 0.001); lower heart rates at initiating cooling (p = 0.003) and after 24 hours of cooling (p < 0.001) and lower average values after 3-72 hours of cooling (p < 0.001); higher body temperature at admission (p < 0.001); and lower body temperature after 24 hours and lower mean values after 3-72 hours of cooling (both p < 0.001). Survival discharge was best explained by higher blood pH (p < 0.05), higher body temperature at admission (p < 0.01), and lower body temperature and heart rate after 24 hours of cooling (p < 0.01 and <0.001, respectively). Lower heart rate, higher body temperature at admission, and lower body temperature during cooling were associated with favorable short-term outcomes.

The Implementation of Targeted Temperature Management: An Evidence-Based Guideline from the Neurocritical Care Society

BACKGROUND

Targeted temperature management (TTM) is often used in neurocritical care to minimize secondary neurologic injury and improve outcomes. TTM encompasses therapeutic hypothermia, controlled normothermia, and treatment of fever. TTM is best supported by evidence from neonatal hypoxic-ischemic encephalopathy and out-of-hospital cardiac arrest, although it has also been explored in ischemic stroke, traumatic brain injury, and intracranial hemorrhage patients. Critical care clinicians using TTM must select appropriate cooling techniques, provide a reasonable rate of cooling, manage shivering, and ensure adequate patient monitoring among other challenges.

METHODS

The Neurocritical Care Society recruited experts in neurocritical care, nursing, and pharmacotherapy to form a writing Committee in 2015. The group generated a set of 16 clinical questions relevant to TTM using the PICO format. With the assistance of a research librarian, the Committee undertook a comprehensive literature search with no back date through November 2016 with additional references up to March 2017.

RESULTS

The Committee utilized GRADE methodology to adjudicate the quality of evidence as high, moderate, low, or very low based on their confidence that the estimate of effect approximated the true effect. They generated recommendations regarding the implementation of TTM based on this systematic review only after considering the quality of evidence, relative risks and benefits, patient values and preferences, and resource allocation.

CONCLUSION

This guideline is intended for neurocritical care clinicians who have chosen to use TTM in patient care; it is not meant to provide guidance regarding the clinical indications for TTM itself. While there are areas of TTM practice where clear evidence guides strong recommendations, many of the recommendations are conditional, and must be contextualized to individual patient and system needs.

Feasibility of a Miniature Esophageal Heat Exchange Device for Rapid Therapeutic Cooling in Newborns: Preliminary Investigations in a Piglet Model

Therapeutic hypothermia (TH) after neonatal encephalopathy, commonly provided by 72 hours of whole-body cooling using a wrap, limits parents' physical contact with their infants affecting bonding and may not be suitable for encephalopathic preterm infants with fragile skin. Alternative cooling methods are unavailable for this population. We investigated in a neonatal pig model the feasibility of achieving a 3.5°C reduction in rectal temperature (T_rectal) similar to clinical TH protocols from 38.5°C (normothermia for pigs) to a target of 35°C ± 0.2°C, using a novel neonatal esophageal heat exchanger (NEHE), compared its efficacy to passive cooling, and investigated its ability to maintain target T_rectal. Ventilated and anesthetized Landrace/Large white newborn pigs had the NEHE inserted. Water at adjustable temperatures and rates flowed down a central tube, returning up a surrounding distensible blind ending latex tube in a continuous loop. An initial experiment guided four subsequent cycles of passive cooling (30 minutes), rewarming to 38.5°C, active esophageal cooling to 35°C ± 0.2°C, active maintenance of target T_rectal (30 minutes), and rewarming. We compared surface, rectal temperature, and hemodynamic changes among passive, active, and maintenance phases, and esophageal histopathology against control. Compared with passive cooling, esophageal cooling achieved target T_rectal significantly earlier (71.3 minutes vs. 17.25 minutes, p = 0.003) with significantly greater rates of reduction in rectal (p = 0.0002) and surface (p = 0.005) temperatures and heart rate (p = 0.04). A water temperature of 39.1°C-40.2°C at a flow of 108-120 mL/min maintained T_rectal around 35°C ± 0.2°C. The higher peak heart rate and blood pressure within 8 minutes of the maintenance phase (p = 0.04) subsequently stabilized. Histopathology showed congestion, edema, and neutrophil infiltration with increasing cycles. Esophageal cooling is feasible and effective in achieving rapid cooling in newborns. Subsequent maintenance at this temperature required continued circulation of warm water. Esophageal histopathology needs further evaluation after 72 hours servo-control cooling with a narrower range of water temperatures in a larger group of animals.

Servo controlled versus manual cooling methods in neonates with hypoxic ischemic encephalopathy

BACKGROUND

Therapeutic hypothermia is known to improve outcomes in neonates with hypoxic ischemic encephalopathy (HIE). There are no studies that have compared servo controlled cooling (SCC) versus manually controlled cooling (MCC) methods in HIE.

AIM

To compare the outcomes of SCC versus MCC in neonates with HIE.

METHODS AND OUTCOME MEASURES

Between Jan 2008 and May 2011, MCC with cool-gel packs was used to achieve rectal temperatures of 33.5 to 34.5°C in our units. Subsequently, we changed to SCC to achieve rectal temperatures of 33 to 34°C. 105 neonates received SCC whereas 95 received MCC. Retrospective study with multivariate analysis was conducted comparing thermoregulation (primary outcome) and neurodevelopmental outcomes of SCC versus MCC.

RESULTS

In the SCC group, 72.3% had stage 2 or 3 HIE versus 77.9% in the MCC. The remaining had stage 1, but attending neonatologists decided to provide cooling. Prescribed rectal temperatures were achieved in 80.5% (5768/7168) instances in SCC versus 72.9% (4449/6108) in MCC (p<0.0001). There were no significant differences in the incidence of 'death or moderate-severe disability' [SCC 26/85 vs MCC 26/87, adjusted odds ratio: 1.29, 95% CI: 0.48, 3.42; p=0.614]. The results were similar after excluding stage 1 HIE [SCC 25/66 vs MCC 26/69, adjusted odds ratio: 1.01, 95% CI: 0.50, 2.02; p=0.981].

CONCLUSIONS

SCC resulted in better thermoregulation in neonates undergoing therapeutic hypothermia. There were no significant differences in neurodevelopmental outcomes, but the study was underpowered to answer this. Randomized trials are needed to fine-tune various aspects of TH in neonates with HIE.

Heart rate response to therapeutic hypothermia in infants with hypoxic-ischaemic encephalopathy

AIM OF THE STUDY

Neonatal encephalopathy (NE) of hypoxic-ischaemic origin may cause death or life-long disability which is reduced by therapeutic hypothermia (TH). Our objective was to assess HR response in infants undergoing TH after perinatal asphyxia.

METHODS

We performed a retrospective case series, from a single-centre tertiary care NICU. We included ninety-two infants with NE of likely hypoxic-ischaemic origin, moderate or severe, treated with TH (n=60) or normothermia (n=32) who had 18 month outcome data and at least 12 HR recordings the first 24h after birth (1998-2010) Bristol, UK. Poor outcome was defined as death or severe disability. Data are reported as medians and 95% confidence intervals (CI).

RESULTS

TH to 33.5°C decreased HR by 30bpm to 92bpm (95% CI: 88, 96) 12h after birth in infants with NE and good outcome as compared to infants treated at normothermia 118bpm (95% CI: 110, 130). Despite constant low rectal temperature, HR increased gradually during cooling from 36 to 72h to 97bpm (89, 106) approaching the normothermia group, 117bpm (96, 133). During TH, infants with poor outcome had higher HR at 12h after birth (112bpm, 95% CI: 92, 115) as compared to infants with good outcome (p=0.004). Inotropic support increased HR by 17bpm in infants with good outcome and by 22bpm in infants with poor outcome.

CONCLUSIONS

In NE, TH decreases HR the first day of life. HR remained lower during TH, but increased during the last day of TH. Infants with poor outcome have higher HR.

Earlier Initiation of Therapeutic Hypothermia by Non-Tertiary Neonatal Units in Victoria, Australia

BACKGROUND

Therapeutic hypothermia is an effective treatment for moderate or severe hypoxic-ischaemic encephalopathy (HIE), with maximal neuroprotective benefit when initiated soon after birth. Early initiation of therapeutic hypothermia in infants with HIE born in geographically distant settings is challenging.

OBJECTIVE

To audit temperature control in infants with HIE treated with hypothermia during neonatal transport in Victoria, Australia.

METHODS

A retrospective database review from September 1, 2008 to August 31, 2012 compared temperatures of transported outborn infants with HIE treated with hypothermia initiated by the referring non-tertiary neonatal unit, with hypothermia initiated by the transport team.

RESULTS

123 infants received therapeutic hypothermia during the study period. Hypothermia treatment commenced significantly earlier [median (interquartile range [IQR]) 1.1 h (0.6-1.7) vs. 3.3 h (2.1-4.5); p < 0.01] with the target temperature (33-34°C) achieved sooner [median (IQR) 3.4 h (2.4-4.6) vs. 4.5 h (3.6-5.5)] when initiated by the referring hospital (n = 71) than by the transport team (n = 52). There was no statistically significant difference in achieving the target temperature before admission to the tertiary neonatal intensive care unit when hypothermia was initiated by the referring unit, compared with by the transport team [51/71 (71.8%) vs. 28/52 (53.9%), odds ratio (95% CI) 2.19 (0.96, 4.96)]. Infants in whom hypothermia was initiated by the referring hospital were more likely to have a recorded temperature below 33°C [22/71 (31.0%) vs. 4/52 (7.7%), odds ratio (95% CI) 5.39 (1.64, 22.83)].

CONCLUSIONS

The target temperature is achieved sooner in infants with moderate or severe HIE when therapeutic hypothermia is initiated by referring non-tertiary neonatal units under guidance from the regional transport service. This practice may enhance neuroprotection for infants with HIE born in non-tertiary units, particularly in remote locations.

Comparison of selective head cooling versus whole-body cooling

BACKGROUND

This study compared selective head cooling (SHC) and whole-body cooling (WBC) in newborns with hypoxic-ischemic encephalopathy (HIE).

METHODS

We conducted a prospective randomized small-scale pilot study in newborns with HIE, born after >35 weeks of gestation. The patients were randomly assigned to receive SHC or WBC.

RESULTS

The SHC group consisted of 17 patients, and the WBC group, 12 patients. There was no significant difference in adverse effects related to cooling therapy between the two groups. During the 12 month study period, seven patients in the SHC group and four in the WBC group died, but the difference was not significant (P = 0.667). Among the patients alive at 12 months after treatment, six in the SHC group and four in the WBC group had severe disabilities; the difference was not significant (P = 0.671). When the composite outcome of death or severe disability was evaluated, the difference between the SHC group (77%, n = 13) and the WBC group (67%, n = 8) was not significant (P = 0.562). Moreover, the number of survivors without disability at 12 months after treatment did not differ significantly between the SHC group (n = 3) and the WBC group (n = 4; P = 0.614).

CONCLUSIONS

There were no significant differences in adverse effects, 12 month neuromotor development, or mortality rate between SHC and WBC in newborns with HIE, born after >35 weeks of gestation.

Using a novel laminar flow unit provided effective total body hypothermia for neonatal hypoxic encephalopathy

AIM

This was a clinical observational trial on a laminar flow device that provides total body hypothermia for infants with hypoxic ischaemic encephalopathy (HIE).

METHODS

We enrolled infants born at up to 35 weeks of gestation, who presented with HIE within six hours of birth. Total body cooling was achieved using the neonatal laminar flow unit for 72 hours, with continuous rectal temperature servo control, isolation and humidification. Outcome measures were cerebral palsy, a Bayley II Mental Development Index score <70, hearing loss or blindness. We compared findings with previously published studies.

RESULTS

We included 26 newborn infants (69% male) with a birthweight of 3.341 ± 1658 g and gestational age of 38.2 ± 3.2 weeks. The majority (62.6%) had a Sarnat HIE score of three and 38.4% had a score of two. Total body cooling (33-34°C) was achieved in 70 minutes and maintained with servo control, showing very little variability until rewarming. At 18-24 months of age, two of the 18 survivors were diagnosed with cerebral palsy and one was diagnosed with impaired hearing.

CONCLUSION

The laminar flow unit proved effective in maintaining moderate total body hypothermia under well-controlled conditions, and our results were very similar to other studies.

Temperature control during therapeutic hypothermia for newborn encephalopathy using different Blanketrol devices

Therapeutic hypothermia improves the survival and neurodevelopmental outcome of infants with newborn encephalopathy of a hypoxic-ischemic origin. The NICHD Neonatal Research Network (NRN) Whole Body Cooling trial used the Cincinnati Sub-Zero Blanketrol II to achieve therapeutic hypothermia. The Blanketrol III is now available and provides additional cooling modes that may result in better temperature control. This report is a retrospective comparison of infants undergoing hypothermia using two different cooling modes of the Blanketrol device. Infants from the NRN trial were cooled with the Blanketrol II using the Automatic control mode (B2 cohort) and were compared with infants from two new NRN centers that adopted the NRN protocol and used the Blanketrol III in a gradient mode (B3 cohort). The primary outcome was the percent time the esophageal temperature stayed between 33°C and 34°C (target 33.5°C) during maintenance of hypothermia. Cohorts had similar birth weight, gestational age, and level of encephalopathy at the initiation of therapy. Baseline esophageal temperature differed between groups (36.6°C ± 1.0°C for B2 vs. 33.9°C ± 1.2°C for B3, p<0.0001) reflecting the practice of passive cooling during transport prior to initiation of active device cooling in the B3 cohort. This difference prevented comparison of temperatures during induction of hypothermia. During maintenance of hypothermia the mean and standard deviation of the percent time between 33°C and 34°C was similar for B2 compared to B3 cohorts (94.8% ± 0.1% vs. 95.8% ± 0.1%, respectively). Both the automatic and gradient control modes of the Blanketrol devices appear comparable in maintaining esophageal temperature within the target range during maintenance of therapeutic hypothermia.

Provision of Therapeutic Hypothermia in Neonatal Transport: A Longitudinal Study and Review of Literature

Background: Worldwide, a significant proportion of infants needing therapeutic hypothermia for hypoxia-ischaemia are transported to a higher-level facility for neonatal intensive care. They pose technical challenges to transport teams in cooling them. Concerns exist about the efficacy of passive cooling in neonatal transport to achieve a neurotherapeutic temprature. Servo-controlled cooling in the standard of care on the neonatal unit. The key question is whether the same standard of care in the neonatal unit can be safely used for therapeutic hypothermia during transport of neonates with suspected hypoxia-ischaemia.

Methods: A prospective cross-sectional survey of United Kingdom (UK) neonatal transport services (n=21) was performed annually from 2011-2014 with a 100% response. The survey ascertained information about service provision and the method of cooling used during transport.

Results: In 2011, all UK neonatal transport services provided therapeutic hypothermia during transport. Servo-control cooling machines were used by only 6 of the 21 teams (30%) while passive cooling was used by 15 of the 21 (70%) teams. In 2012 9 of the 21 teams (43%) were using servo-control. By 2014 the number of teams using servo-control cooling had more than doubled to 15 of the 21 (62%) services. Teams have done this through modification of transport trolleys and dedicated ambulances.

Conclusion: Servo-controlled cooling in neonatal transport is becoming more common in the UK. The question remains whether it should be endorsed as a standard of care. Some teams continue to passively cool neonates with hypoxia-ischaemia during transport. This article reviews the drivers, current evidence, safety and processes involved in provision of therapeutic hypothermia during neonatal transport to enable teams to decide what would be the right option for them.

Neuroprotective body hypothermia among newborns with hypoxic ischemic encephalopathy: three-year experience in a tertiary university hospital. A retrospective observational study

CONTEXT AND OBJECTIVE

Neonatal hypoxic-ischemic encephalopathy is associated with high morbidity and mortality. Studies have shown that therapeutic hypothermia decreases neurological sequelae and death. Our aim was therefore to report on a three-year experience of therapeutic hypothermia among asphyxiated newborns.

DESIGN AND SETTING

Retrospective study, conducted in a university hospital.

METHODS

Thirty-five patients with perinatal asphyxia undergoing body cooling between May 2009 and November 2012 were evaluated.

RESULTS

Thirty-nine infants fulfilled the hypothermia protocol criteria. Four newborns were removed from study due to refractory septic shock, non-maintenance of temperature and severe coagulopathy. The median Apgar scores at 1 and 5 minutes were 2 and 5. The main complication was infection, diagnosed in seven mothers (20%) and 14 newborns (40%). Convulsions occurred in 15 infants (43%). Thirty-one patients (88.6%) required mechanical ventilation and 14 of them (45%) were extubated within 24 hours. The duration of mechanical ventilation among the others was 7.7 days. The cooling protocol was started 1.8 hours after birth. All patients showed elevated levels of creatine phosphokinase, creatine phosphokinase- MB and lactate dehydrogenase. There was no severe arrhythmia; one newborn (2.9%) presented controlled coagulopathy. Four patients (11.4%) presented controlled hypotension. Twenty-nine patients (82.9%) underwent cerebral ultrasonography and 10 of them (34.5%) presented white matter hyper-echogenicity. Brain magnetic resonance imaging was performed on 33 infants (94.3%) and 11 of them (33.3%) presented hypoxic-ischemic changes. The hospital stay was 23 days. All newborns were discharged. Two patients (5.8%) needed gastrostomy.

CONCLUSION

Hypothermia as therapy for asphyxiated newborns was shown to be safe.

Comparison of selective head cooling therapy and whole body cooling therapy in newborns with hypoxic ischemic encephalopathy: short term results

AIM

In this study, it was aimed to investigate which method was superior by applying selective head cooling or whole body cooling therapy in newborns diagnosed with moderate or severe hypoxic ischemic encephalopathy.

MATERIALS AND METHOD

Newborns above the 35th gestational age diagnosed with moderate or severe hypoxic ischemic encephalopathy were included in the study and selective head cooling or whole body cooling therapy was performed randomly. The newborns who were treated by both methods were compared in terms of adverse effects in the early stage and in terms of short-term results. Ethics committee approval was obtained for the study (06.01.2010/35).

RESULTS

Fifty three babies diagnosed with hypoxic ischemic encephalopathy were studied. Selective head cooling was applied to 17 babies and whole body cooling was applied to 12 babies. There was no significant difference in terms of adverse effects related to cooling therapy between the two groups. When the short-term results were examined, it was found that the hospitalization time was 34 (7-65) days in the selective head cooling group and 18 (7-57) days in the whole body cooling group and there was no significant difference between the two groups (p=0.097). Four patients in the selective head cooling group and two patients in the whole body cooling group were discharged with tracheostomy because of the need for prolonged mechanical ventilation and there was no difference between the groups in terms of discharge with tracheostomy (p=0.528). Five patients in the selective head cooling group and three patients in the whole body cooling group were discharged with a gastrostomy tube because they could not be fed orally and there was no difference between the groups in terms of discharge with a gastrostomy tube (p=0.586). One patient who was applied selective head cooling and one patient who was applied whole body cooling died during hospitalization and there was no difference between the groups in terms of mortality (p=0.665).

CONCLUSIONS

There is no difference between the methods of selective head cooling and whole body cooling in terms of adverse effects and short-term results.

Cooling in a low-resource environment: lost in translation

Although cooling therapy has been the standard of care for neonatal encephalopathy (NE) in high-income countries for more than half a decade, it is still not widely used in low- and middle-income countries (LMIC), which bear 99% of the encephalopathy burden; neither is it listed as a priority research area in global health. Here we explore the major roadblocks that prevent the use of cooling in LMIC, including differences in population comorbidities, suboptimal intensive care, and the lack of affordable servo-controlled cooling devices. The emerging data from LMIC suggest that the incidence of coexisting perinatal infections in NE is no different to that in high-income countries, and that cooling can be effectively provided without tertiary intensive care and ventilatory support; however, the data on safety and efficacy of cooling are limited. Without adequately powered clinical trials, the creeping and uncertain introduction of cooling therapy in LMIC will be plagued by residual safety concerns, and any therapeutic benefit will be even more difficult to translate into widespread clinical use.

Unobtrusive Monitoring of Neonatal Brain Temperature Using a Zero-Heat-Flux Sensor Matrix

The temperature of preterm neonates must be maintained within a narrow window to ensure their survival. Continuously measuring their core temperature provides an optimal means of monitoring their thermoregulation and their response to environmental changes. However, existing methods of measuring core temperature can be very obtrusive, such as rectal probes, or inaccurate/lagging, such as skin temperature sensors and spot-checks using tympanic temperature sensors. This study investigates an unobtrusive method of measuring brain temperature continuously using an embedded zero-heat-flux (ZHF) sensor matrix placed under the head of the neonate. The measured temperature profile is used to segment areas of motion and incorrect positioning, where the neonate's head is not above the sensors. We compare our measurements during low motion/stable periods to esophageal temperatures for 12 preterm neonates, measured for an average of 5 h per neonate. The method we propose shows good correlation with the reference temperature for most of the neonates. The unobtrusive embedding of the matrix in the neonate's environment poses no harm or disturbance to the care work-flow, while measuring core temperature. To address the effect of motion on the ZHF measurements in the current embodiment, we recommend a more ergonomic embedding ensuring the sensors are continuously placed under the neonate's head.

Systemic effects of whole-body cooling to 35 °C, 33.5 °C, and 30 °C in a piglet model of perinatal asphyxia: implications for therapeutic hypothermia

INTRODUCTION

The precise temperature for optimal neuroprotection in infants with neonatal encephalopathy is unclear. Our aim was to assess systemic effects of whole-body cooling to 35 °C, 33.5 °C, and 30 °C in a piglet model of perinatal asphyxia.

METHODS

Twenty-eight anesthetized male piglets aged <24 h underwent hypoxia-ischemia (HI) and were randomized to normothermia or cooling to rectal temperature (Trec) 35 °C, 33.5 °C, or 30 °C during 2-26 h after insult (n = 7 in each group). HR, MABP, and Trec were recorded continuously.

RESULTS

Five animals cooled to 30 °C had fatal cardiac arrests. During 30 °C cooling, heart rate (HR) was lower vs. normothermia (P < 0.001). Although mean arterial blood pressure (MABP) did not vary between groups, more fluid boluses were needed at 30 °C than at normothermia (P < 0.02); dopamine use was higher at 30 °C than at normothermia or 35 °C (P = 0.005 and P = 0.02, respectively). Base deficit was increased at 30 °C at 12, 24, and 36 h vs. all other groups (P < 0.05), pH was acidotic at 36 h vs. normothermia (P = 0.04), and blood glucose was higher for the 30 °C group at 12 h vs. the normothermia and 35 °C groups (P < 0.05). Potassium was lower at 12 h in the 30 °C group vs. the 33.5 °C and 35 °C groups. There was no difference in cortisol level between groups.

DISCUSSION

Cooling to 30 °C led to metabolic derangement and more cardiac arrests and deaths than cooling to 33.5 °C or 35 °C. Inadvertent overcooling should be avoided.

Temperature profile and outcomes of neonates undergoing whole body hypothermia for neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Decreases below the target temperature were noted among neonates undergoing cooling in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network Trial of whole body hypothermia for neonatal hypoxic-ischemic encephalopathy.

OBJECTIVE

To examine the temperature profile and impact on outcome among ≥ 36 wk gestation neonates randomized at ≤ 6 hrs of age targeting an esophageal temperature of 33.5°C for 72 hrs.

DESIGN, SETTING, PATIENTS

Infants with intermittent temperatures recorded of <32.0°C during induction and maintenance of cooling were compared to all other cooled infants, and the relationship with outcome at 18 months was evaluated.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were no differences in the stage of encephalopathy, acidosis, or 10 min Apgar scores between infants with temperatures of <32.0°C during induction (n = 33) or maintenance (n = 10) and all other infants who were cooled (n = 58); however, birth weight was lower and the need for blood pressure support higher among infants with temperatures of <32.0°C compared to all other cooled infants. No increase in acute adverse events was noted among infants with temperatures of <32.0°C, and hours spent at <32°C was not associated with the primary outcome of death or moderate/severe disability or the Bayley II Mental Developmental Index at 18 months.

CONCLUSIONS

Term infants with a lower birth weight are at risk for decreasing temperatures of <32.0°C while undergoing body cooling using a servo-controlled system. This information suggests extra caution during the application of hypothermia as these lower birth weight infants are at risk for overcooling. Our findings may assist in planning additional trials of lower target temperature for neonatal hypoxic-ischemic encephalopathy.

Therapeutic hypothermia for acute neurological injuries

Therapeutic hypothermia (TH) is the intentional reduction of core body temperature to 32°C to 35°C, and is increasingly applied by intensivists for a variety of acute neurological injuries to achieve neuroprotection and reduction of elevated intracranial pressure. TH improves outcomes in comatose patients after a cardiac arrest with a shockable rhythm, but other off-label applications exist and are likely to increase in the future. This comprehensive review summarizes the physiology and cellular mechanism of action of TH, as well as different means of TH induction and maintenance with potential side effects. Indications of TH are critically reviewed by disease entity, as reported in the most recent literature, and evidence-based recommendations are provided.