Evaluating a simple method of neuroprotective hypothermia for newborn infants

Therapeutic hypothermia for neonates with hypoxic-ischaemic encephalopathy in low- and lower-middle-income countries: a systematic review and meta-analysis

Hypoxic-ischaemic encephalopathy (HIE) is a major cause of mortality and neurodevelopmental disability, especially in low-income countries. While therapeutic hypothermia has been shown to reduce morbidity and mortality in infants with HIE, some clinical trials in low-income countries have reported an increase in the risk of mortality. We conducted a systematic review and meta-analysis of all randomized and quasi-randomized controlled trials conducted in low-income and lower-middle-income countries that compared cooling therapy with standard care for HIE. Our primary outcome was composite of neonatal mortality and neurodevelopmental disability at 6 months or beyond. The review was registered with PROSPERO (CRD42022352728). Our review included 11 randomized controlled trials with 1324 infants with HIE. The composite of death or disability at 6 months or beyond was lower in therapeutic hypothermia group (RR 0.78, 95% CI 0.66-0.92, I2 = 85%). Neonatal mortality rate did not differ significantly between cooling therapy and standard care (RR 0.92, 95% CI 0.76-1.13, I2 = 61%). Additionally, the cooled group exhibited significantly lower rates of neurodevelopmental disability at or beyond 6 months (RR 0.34, 95%CI 0.22-0.52, I2 = 0%). Our analysis found that neonatal mortality rate did not differ between cooled and noncooled infants in low- and lower-middle-income countries. Cooling may have a beneficial effect on neurodevelopmental disability and the composite of death or disability at 6 months or beyond.

Analgesia and sedation strategies in neonates undergoing whole-body therapeutic hypothermia: A scoping review

BACKGROUND

Therapeutic hypothermia (TH) is a widely practiced neuroprotective strategy for neonates with hypoxic-ischemic encephalopathy. Induced hypothermia is associated with shivering, cold pain, agitation, and distress.

OBJECTIVE

This scoping review determines the breadth of research undertaken for pain and stress management in neonates undergoing hypothermia therapy, the pharmacokinetics of analgesic and sedative medications during hypothermia and the effect of such medication on short- and long-term neurological outcomes.

METHODS

We searched the following online databases namely, (i) MEDLINE, (ii) Web of Science, (iii) Cochrane Library, (iv) Scopus, (v) CINAHL, and (vi) EMBASE to identify published original articles between January 2005 and December 2022. We included only English full-text articles on neonates treated with TH and reported the sedation/analgesia strategy used. We excluded articles that reported TH on transport or extracorporeal membrane oxygenation, did not report the intervention strategies for sedation/analgesia, and reported hypoxic-ischemic encephalopathy in which hypothermia was not applied.

RESULTS

The eligible publications (n = 97) included cohort studies (n = 72), non-randomized experimental studies (n = 2), pharmacokinetic studies (n = 4), dose escalation feasibility trial (n = 1), cross-sectional surveys (n = 5), and randomized control trials (n = 13). Neonatal Pain, Agitation, and Sedation Scale (NPASS) is the most frequently used pain assessment tool in this cohort. The most frequently used pharmacological agents are opioids (Morphine, Fentanyl), benzodiazepine (Midazolam) and Alpha2 agonists (Dexmedetomidine). The proportion of neonates receiving routine sedation-analgesia during TH is center-specific and varies from 40-100% worldwide. TH alters most drugs' metabolic rate and clearance, except for Midazolam. Dexmedetomidine has additional benefits of thermal tolerance, neuroprotection, faster recovery, and less likelihood of seizures. There is a wide inter-individual variability in serum drug levels due to the impact of temperature, end-organ dysfunction, postnatal age, and body weight on drug metabolism.

CONCLUSIONS

No multidimensional pain scale has been tested for reliability and construct validity in hypothermic encephalopathic neonates. There is an increasing trend towards using routine sedation/analgesia during TH worldwide. Wide variability in the type of medication used, administration (bolus versus infusion), and dose ranges used emphasizes the urgent need for standardized practice recommendations and guidelines. There is insufficient data on the long-term neurological outcomes of exposure to these medications, adjusted for underlying brain injury and severity of encephalopathy. Future studies will need to develop framework tools to enable precise control of sedation/analgesia drug exposure customized to individual patient needs.

Incidence and outcomes of intrapartum-related neonatal encephalopathy in low-income and middle-income countries: a systematic review and meta-analysis

AIM

To examine the incidence of intrapartum-related neonatal encephalopathy, and neonatal mortality and neurodevelopmental outcomes associated with it in low-income and middle-income countries.

METHODS

Reports were included when neonatal encephalopathy diagnosed clinically within 24 hours of birth in term or near-term infants born after intrapartum hypoxia-ischaemia defined as any of the following: (1) pH≤7.1 or base excess ≤-12 or lactate ≥6, (2) Apgar score ≤5 at 5 or 10 min, (3) continuing resuscitation at 5 or 10 min or (4) no cry from baby at 5 or 10 min. Peer-reviewed articles were searched from Ovid MEDLINE, Cochrane, Web of Science and WHO Global Index Medicus with date limits 1 November 2009 to 17 November 2021. Risk of bias was assessed using modified Newcastle Ottawa Scale. Inverse variance of heterogenicity was used for meta-analyses.

RESULTS

There were 53 reports from 51 studies presenting data on 4181 children with intrapartum-related neonatal encephalopathy included in the review. Only five studies had data on incidence, which ranged from 1.5 to 20.3 per 1000 live births. Neonatal mortality was examined in 45 studies and in total 636 of the 3307 (19.2%) infants died. Combined outcome of death or moderate to severe neurodevelopmental disability was reported in 19 studies and occurred in 712 out of 1595 children (44.6%) with follow-up 1 to 3.5 years.

CONCLUSION

Though there has been progress in some regions, incidence, case mortality and morbidity in intrapartum-related neonatal encephalopathy has been static in the last 10 years.

PROSPERO REGISTRATION NUMBER

CRD42020177928.

Treatment device for neonatal birth asphyxia related Hypoxic Ischemic Encephalopathy

Background

Birth asphyxia is a leading cause of neonatal brain injury, morbidity, and mortality globally. It leads to a multi-organ dysfunction in the neonate and to a neurological dysfunction called Hypoxic Ischemic Encephalopathy (HIE). Cooling therapy is commonly used to slow or stop the damaging effects of birth asphyxia. However, most of the cooling devices used in the healthcare facility do not have a rewarming functionality after cooling therapy. A separate rewarming device, usually a radiant warmer or incubator is used to rewarm the infant after therapy, causing additional burden to the healthcare system and infant families. The objective of this project was, therefore, to design and develop a cost-effective and efficient total body cooling and rewarming device.

Methods

Our design includes two water reservoirs that operate by pumping cold and warm sterile water to a mattress. After decreasing the infant’s core body temperature to 33.5 °C, the system is designed to maintain it for 72 h. Feedback for temperature regulation is provided by the rectal and mattress temperature sensors. Once the cooling therapy is completed, the system again rewarms the water inside the mattress and gradually increases the neonate temperature to 36.5–37 °C. The water temperature sensors’ effectiveness was evaluated by adding 1000 ml of water to the reservoir and cooling and warming to the required level of temperature using Peltier. Then a digital thermometer was used as a gold standard to compare with the sensor’s readings. This was performed for five iterations.

Results

The prototype was built and gone through different tests and iterations. The proposed device was tested for accuracy, cost-effectiveness and easy to use. Ninety-three point two percent accuracy has been achieved for temperature sensor measurement, and the prototype was built only with a component cost of less than 200 USD. This is excluding design, manufacturing, and other costs.

Conclusion

A device that can monitor and regulate the neonate core body temperature at the neuroprotective range is designed and developed. This is achieved by continuous monitoring and regulation of the water reservoirs, mattress, and rectal temperatures. The device also allows continuous monitoring of the infant’s body temperature, mattress temperature, reservoir temperature, and pulse rate. The proposed device has the potential to play a significant role in reducing neonatal brain injury and death due to HIE, especially in low resource settings, where the expertise and the means are scarce.

Effects of therapeutic hypothermia on death among asphyxiated neonates with hypoxic-ischemic encephalopathy: A systematic review and meta-analysis of randomized control trials

Background

Hypoxic perinatal brain injury is caused by lack of oxygen to baby’s brain and can lead to death or permanent brain damage. However, the effectiveness of therapeutic hypothermia in birth asphyxiated infants with encephalopathy is uncertain. This systematic review and meta-analysis was aimed to estimate the pooled relative risk of mortality among birth asphyxiated neonates with hypoxic-ischemic encephalopathy in a global context.

Methods

We used the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines to search randomized control trials from electronic databases (PubMed, Cochrane library, Google Scholar, MEDLINE, Embase, Scopus, Web of Science, Cochrane Central Register of Controlled Trials (CENTRAL), and meta register of Current Controlled Trials (mCRT)). The authors extracted the author’s name, year of publication, country, method of cooling, the severity of encephalopathy, the sample size in the hypothermic, and non-hypothermic groups, and the number of deaths in the intervention and control groups. A weighted inverse variance fixed-effects model was used to estimate the pooled relative risk of mortality. The subgroup analysis was done by economic classification of countries, methods of cooling, and cooling devices. Publication bias was assessed with a funnel plot and Eggers test. A sensitivity analysis was also done.

Results

A total of 28 randomized control trials with a total sample of 35, 92 (1832 hypothermic 1760 non-hypothermic) patients with hypoxic-ischemic encephalopathy were used for the analysis. The pooled relative risk of mortality after implementation of therapeutic hypothermia was found to be 0.74 (95%CI; 0.67, 0.80; I² = 0.0%; p<0.996). The subgroup analysis revealed that the pooled relative risk of mortality in low, low middle, upper-middle and high income countries was 0.32 (95%CI; -0.95, 1.60; I² = 0.0%; p<0.813), 0.5 (95%CI; 0.14, 0.86; I² = 0.0%; p<0.998), 0.62 (95%CI; 0.41–0.83; I² = 0.0%; p<0.634) and 0.76 (95%CI; 0.69–0.83; I² = 0.0%; p<0.975) respectively. The relative risk of mortality was the same in selective head cooling and whole-body cooling method which was 0.74. Regarding the cooling device, the pooled relative risk of mortality is the same between the cooling cap and cooling blanket (0.74). However, it is slightly lower (0.73) in a cold gel pack.

Conclusions

Therapeutic hypothermia reduces the risk of death in neonates with moderate to severe hypoxic-ischemic encephalopathy. Both selective head cooling and whole-body cooling method are effective in reducing the mortality of infants with this condition. Moreover, low income countries benefit the most from the therapy. Therefore, health professionals should consider offering therapeutic hypothermia as part of routine clinical care to newborns with hypoxic-ischemic encephalopathy especially in low-income countries.

[The neuroprotective role of exogenous TERT gene in neonatal rats with hypoxic-ischemic brain damage]

OBJECTIVE

To study the effect of telomerase reverse transcriptase (TERT) on cell apoptosis in neonatal rat brains after hypoxic-ischemic brain injury (HIBD).

METHODS

A total of 72 neonatal rats were divided into sham, vehicle, HIBD and TERT groups. HIBD was induced by Rice method in the later three groups. The neonatal rats in the vehicle and TERT groups were injected with plasmids containing mock or full length TERT by an intracerebroventricular injection 30 minutes after hypoxic-ischemic (HI) injury. Pathological changes of brain tissue were observed by hematoxylin and eosin (HE) staining. Western blot was used to detect the protein expression of TERT, apoptosis-inducing factor (AIF) and cleaved caspase 3 (CC3). Apoptotic cells were detected by TUNEL staining.

RESULTS

Western blot showed that TERT protein was dramatically increased in the vehicle, HIBD and TERT groups compared with the sham group. Compared with the vehicle and HIBD groups, TERT protein in the TERT group was significantly upregulated. Compared with the sham group, there was a significant increase in apoptotic index and expression of AIF and CC3 proteins in the vehicle and HIBD groups (p<0.01). The TERT group showed decreased expression of AIF and CC3 proteins and apoptotic index compared with the vehicle and HIBD groups (p<0.01).

CONCLUSIONS

TERT can inhibit cell apoptosis induced by HI and might have a neuroprotective role in developing brain with HIBD.

Therapeutic hypothermia for neonatal hypoxic-ischaemic encephalopathy had favourable outcomes at a referral hospital in a middle-income country

AIM

This South African study documented the survival and neurodevelopmental outcomes of infants with hypoxic-ischaemic encephalopathy (HIE) after introducing cooling to a neonatal intensive care unit and identified early markers for neurodevelopmental outcome.

METHODS

We retrospectively reviewed infants that received cooling according to the Total Body Hypothermia trial protocol from 2008 to 2011. Infants were screened with the Bayley Scales of Infant and Toddler Development, Third Edition, at one year of age and underwent neurological and hearing assessments.

RESULTS

Data on 99 infants with HIE showed that 45% of cases were moderate, 23% severe and 32% mild. An abnormal amplitude integrated electro-encephalogram (aEEG) background was documented in 45 cases within 24 hours. Magnetic resonance imaging (MRI) scans were consistent with HIE in all but one case. We reviewed 50 traceable survivors at one year. Development was significantly impaired in nine and 41 were normal or mildly impaired. A severely abnormal aEEG background, severe HIE and an abnormal MRI were associated with death and severe impairment. A good suck, mild HIE, primiparity and normal MRI were associated with good outcomes.

CONCLUSION

Most infants with HIE survived without major impairment. Previously described predictors of neurodevelopmental outcome were good surrogate markers in this population.

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.

Therapeutic cooling for perinatal asphyxia-Indian experience

Therapeutic hypothermia (TH) has been established as standard of care for term babies with perinatal asphyxia in developed countries. However, it is yet to gain momentum in India. This review summarizes some of the TH trials conducted in India and the various related issues in adapting the same for the Indian context.

Early clinical predictors of a severely abnormal amplitude-integrated electroencephalogram at 48 hours in cooled neonates

AIM

There is a need to identify infants with hypoxic ischaemic encephalopathy who have a poor outcome despite therapeutic hypothermia. A severely abnormal amplitude-integrated electroencephalogram at 48 h predicts death or disability. Our aim was to determine whether clinical assessment at age 3-5 h predicts a severely abnormal amplitude-integrated electroencephalogram at 48 h or death in cooled infants.

METHODS

Forty-one cooled infants, ≥36 weeks' gestation, with moderate-to-severe hypoxic ischaemic encephalopathy, were prospectively enrolled. Infants who were moribund, had congenital conditions associated with encephalopathy or had severe cardio-respiratory instability were excluded. The predictive abilities of the Thompson encephalopathy score and individual signs at age 3-5 h were assessed.

RESULTS

All infants with a Thompson score ≥16 at 3-5 h had a severely abnormal amplitude-integrated electroencephalogram at 6 h and an abnormal short-term outcome. At 48 h, 75% had a severely abnormal aEEG or died vs. 18% with a score <16 (p = 0.004). Multivariate analysis did not find a significant independent association with any of the individual signs.

CONCLUSION

The Thompson score could be useful to identify infants who will have a poor outcome despite cooling. A score ≥16 should be validated as a prespecified variable in prospective studies.

Early clinical signs in neonates with hypoxic ischemic encephalopathy predict an abnormal amplitude-integrated electroencephalogram at age 6 hours

Background

An early clinical score predicting an abnormal amplitude-integrated electroencephalogram (aEEG) or moderate-severe hypoxic ischemic encephalopathy (HIE) may allow rapid triage of infants for therapeutic hypothermia. We aimed to determine if early clinical examination could predict either an abnormal aEEG at age 6 hours or moderate-severe HIE presenting within 72 hours of birth.

Methods

Sixty infants ≥ 36 weeks gestational age were prospectively enrolled following suspected intrapartum hypoxia and signs of encephalopathy. Infants who were moribund, had congenital conditions that could contribute to the encephalopathy or had severe cardio-respiratory instability were excluded. Predictive values of the Thompson HIE score, modified Sarnat encephalopathy grade (MSEG) and specific individual signs at age 3–5 hours were calculated.

Results

All of the 60 infants recruited had at least one abnormal primitive reflex. Visible seizures and hypotonia at 3–5 hours were strongly associated with an abnormal 6-hour aEEG (specificity 88% and 92%, respectively), but both had a low sensitivity (47% and 33%, respectively). Overall, 52% of the infants without hypotonia at 3–5 hours had an abnormal 6-hour aEEG. Twelve of the 29 infants (41%) without decreased level of consciousness at 3–5 hours had an abnormal 6-hour aEEG (sensitivity 67%; specificity 71%). A Thompson score ≥ 7 and moderate-severe MSEG at 3–5 hours, both predicted an abnormal 6-hour aEEG (sensitivity 100 vs. 97% and specificity 67 vs. 71% respectively). Both assessments predicted moderate-severe encephalopathy within 72 hours after birth (sensitivity 90%, vs. 88%, specificity 92% vs. 100%). The 6-hour aEEG predicted moderate-severe encephalopathy within 72 hours (sensitivity 75%, specificity 100%) but with lower sensitivity (p = 0.0156) than the Thompson score (sensitivity 90%, specificity 92%). However, all infants with a normal 3- and 6-hour aEEG with moderate-severe encephalopathy within 72 hours who were not cooled had a normal 24-hour aEEG.

Conclusions

The encephalopathy assessment described by the Thompson score at age 3–5 hours is a sensitive predictor of either an abnormal 6-hour aEEG or moderate-severe encephalopathy presenting within 72 hours after birth. An early Thompson score may be useful to assist with triage and selection of infants for therapeutic hypothermia.

Therapeutic hypothermia for neonatal encephalopathy in low- and middle-income countries: a systematic review and meta-analysis

Although selective or whole body cooling combined with optimal intensive care improves outcomes following neonatal encephalopathy in high-income countries, the safety and efficacy of cooling in low-and middle-income countries is not known.

Whole body cooling in newborn infants with perinatal asphyxial encephalopathy in a low resource setting: a feasibility trial

OBJECTIVE

To determine the feasibility and safety of whole body cooling in newborn infants with perinatal asphyxial encephalopathy in a low resource setting.

DESIGN

Feasibility trial.

SETTING

Tertiary care perinatal centre.

SUBJECTS

Infants born at > 35 weeks gestation with perinatal asphyxia were included in the study.

INTERVENTIONS

Infants were cooled to a rectal temperature of 33 ± 0.5°C for 72 hours using cloth-covered ice-gel packs. Vital parameters were monitored continuously.

OUTCOME MEASURES

The primary outcome was the achievement of target temperature within 1 hour of initiation of treatment and maintaining the target temperature for 72 hours. Adverse events and possible complications of hypothermia were the secondary outcomes measured.

RESULTS

Twenty infants were included in the study. The mean time taken to achieve target rectal temperature was 52 ± 25 minutes. The mean rectal temperature during cooling was 32.9 ± 0.11ºC. The target temperature could be maintained for 72 hours without difficulty in all babies. Adverse events observed during cooling were thrombocytopenia (25%), sinus bradycardia (25%), deranged bleeding parameters (20%), aposteatonecrosis (15%), hyperglycemia (15%), hypoglycemia (10%), hypoxemia (5%), life-threatening coagulopathy (5%) and death (5%). Shivering was noted in many of the babies, especially in the initial phase of cooling.

CONCLUSION

Whole body cooling in term infants with perinatal asphyxia is achievable, safe and inexpensive in a low-resource setting.