Transporting neonates with hypoxic-ischemic encephalopathy utilizing active hypothermia

Comparing Three Methods of Therapeutic Hypothermia Among Transported Neonates with Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) and associated multiorgan injury are significant causes of morbidity and mortality in term and near-term neonates. Therapeutic hypothermia (TH) is the current standard of care for neuroprotection in neonates with HIE. In our experience, the majority of babies born with HIE were found in nontertiary care facilities in our region, where effective methods of cooling during transport to tertiary care centers are desirable. Most centers initiate passive TH at referral hospitals, while active cooling is typically initiated during transport. The objective of this study was to evaluate the effectiveness of three methods of cooling during transport of neonates with HIE in southern Alberta. In this prospective cohort study, 186 neonates with HIE were transported between January 2013 and December 2021. Among the 186 neonates, 47 were passively cooled, 36 actively cooled with gel packs, and 103 cooled with a servo-controlled cooling device. The clinical characteristics were comparable for the three groups, with no difference in adverse events. Fifteen neonates (8%) died and 54 neonates (29%) suffered radiologically determined brain injury. Servo-controlled cooling was found to be superior to other methods in maintaining a target temperature without significant fluctuation during transport and with temperature in the target range on arrival at tertiary care facilities. The rate of overcooling was also lower in the servo-controlled group compared with other groups. There were no statistically significant differences between the groups in relation to mortality and brain MRI changes associated with HIE. Adjusting for GA, 10-minute Apgar score, base excess, HIE stage, and need for intubation during transport, passive cooling increased the odds of temperature fluctuation outside the range by 12-fold and gel pack cooling by 13-fold compared with servo-controlled cooling. The use of servo-controlled TH devices should be the preferred practice wherever feasible. (REB17-1334_REN3).

Neonatal Transport Safety Metrics and Adverse Event Reporting: A Systematic Review

OBJECTIVE

Neonatal transports are an essential component of regionalized medical systems. Neonates who are unstable after birth require transport to a higher level of care by neonatal transport teams. Data on adverse events on neonatal transports are limited. The aim of this study was to identify, evaluate, and summarize the findings of all relevant studies on adverse events on neonatal transports.

METHODS

We identified 38 studies reporting adverse events on neonatal transports from January 1, 2000, to December 31, 2019. The adverse events were distributed into 5 categories: vital sign abnormalities, laboratory value abnormalities, equipment challenges, system challenges, cardiopulmonary resuscitation, and transport-related mortality.

RESULTS

Most of the evidence surrounds vital sign abnormalities during transport (n = 28 studies), with hypothermia as the most frequently reported abnormal vital sign. Fourteen studies addressed laboratory abnormalities, 12 reported on events related to equipment issues, and 4 reported on system issues that lead to adverse events on transport. Of the 38 included studies, 12 included mortality related to transport as an outcome, and 4 reported on cardiopulmonary resuscitation during transport. There were significant variations in samples, definitions of adverse events, and research quality.

CONCLUSION

Adverse events during neonatal transport have been illuminated in various ways, with vital sign abnormalities most commonly explored in the literature. However, considerable variation in studies limits a clear understanding of the relative frequencies of each type of adverse event. The transport safety field would benefit from more efforts to standardize adverse event definitions, collect safety data prospectively, and pool data across larger care systems.

Cooling strategies during neonatal transport for hypoxic-ischaemic encephalopathy

AIM

We reviewed the literature on cooling methods during transport of newborn infants with hypoxic-ischaemic encephalopathy (HIE) born in a non-tertiary centre and transferred to a neonatal intensive care unit for therapeutic hypothermia.

METHODS

The electronic databases CENTRAL, MEDLINE, Embase, CINAHL, and Scopus were searched from inception up to 8 March 2022 for studies comparing cooling versus no cooling, active versus passive cooling, and servo-controlled versus non-servo-controlled cooling. Odds ratio and confidence of interval were calculated for dichotomous outcomes and mean difference and confidence interval for continuous outcomes.

RESULTS

The final analysis included 14 studies, 1 randomised and 13 non-randomised, involving 1098 newborn infants. Compared with the other cooling methods, servo-controlled active cooling was more likely to maintain body temperature within the target range of 33°C-34°C on arrival at a neonatal intensive care unit: odds ratio 13.58, 95% confidence interval 4.32-42.66, risk difference 0.33, 95% confidence interval 0.19-0.46; 224 participants; three studies; I² 0%. The certainty of evidence was low. Only five studies reported mortality rates.

CONCLUSION

Servo-controlled active cooling may be the preferred method during transport of newborn infants with HIE. A future area of focus should be long-term neurodevelopmental outcomes after servo-controlled active cooling.

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.

Prevention of excessive hypothermia in infants with hypoxic ischemic encephalopathy prior to admission to a quaternary care center: a neonatal outreach educational project

OBJECTIVE

Excessive hypothermia is common in infants that receive passive cooling for hypoxic ischemic encephalopathy (HIE). Our goal was to reduce the number of infants with admission temperature <33 °C from 33% to less than 10% by December 2017.

METHODS

Outcome measures included the number of infants with admission temperature <33 °C and number of infants with temperature within therapeutic range. Interventions included implementation of passive cooling guidelines and outreach education to birth hospitals and transport team. We used statistical process control chart to compare outcomes over a 3 year period.

RESULTS

The number of infants with admission temperature <33 °C decreased from 33.3% to 5.5% (p = 0.013). The number of infants with admission temperature within target range for hypothermia therapy increased from 61.1% to 77.7% (p = 0.014). Balancing measures and complications remained unchanged.

CONCLUSION

Implementation of passive cooling guidelines and outreach education led to significant decrease in excessive hypothermia in infants with HIE.

Passive hypothermia (≥35 - <36°C) during transport of newborns with hypoxic-ischaemic encephalopathy

BACKGROUND

Hypothermia initiated in the first six hours of life in term infants with hypoxic ischemic encephalopathy reduces the risk of death and severe neurological sequelae. Our study's principal objective was to evaluate transport predictors potentially influencing arrival in NICU (Neonatal Intensive Care Unit) at a temperature ≥35-<36°C.

METHODOLOGY/PRINCIPAL FINDINGS

A multi-centric, prospective cohort study was conducted during 18 months by the three Neonatal Transport Teams and 13 NICUs. Newborns were selected for inclusion according to biological and clinical criteria before transport using passive hypothermia using a target temperature of ≥35-<36°C. Data on 120 of 126 inclusions were available for analysis. Thirty-three percent of the children arrived in NICU with the target temperature of ≥35-<36°C. The mean temperature for the whole group of infants on arrival in NICU was 35.4°C (34.3-36.5). The median age of all infants on arrival in NICU was 3h03min [2h25min-3h56min]. Three infants arrived in NICU with a temperature of <33°C and eleven with a temperature ≥37°C. Adrenaline during resuscitation was associated with a lower mean temperature on arrival in NICU.

CONCLUSIONS/SIGNIFICANCE

Our strategy using ≥35-<36°C passive hypothermia combined with short transport times had little effect on temperature after the arrival of Neonatal Transport Team although did reduce numbers of infants arriving in NICU in deep hypothermia. For those infants where hypothermia was discontinued in NICU our strategy facilitated re-warming. Re-adjustment to a lower target temperature to ≥34.5-<35.5°C may reduce the proportion of infants with high/normothermic temperatures.

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.