Chest compression during sustained inflation versus 3:1 chest compression:ventilation ratio during neonatal cardiopulmonary resuscitation: a randomised feasibility trial

Sustained inflation and chest compression versus 3:1 chest compression to ventilation ratio during cardiopulmonary resuscitation of asphyxiated newborns (SURV1VE): A cluster randomised controlled trial

OBJECTIVE

In newborn infants requiring chest compression (CC) in the delivery room (DR) does continuous CC superimposed by a sustained inflation (CC+SI) compared with a 3:1 compression:ventilation (3:1 C:V) ratio decreases time to return of spontaneous circulation (ROSC).

DESIGN

International, multicenter, prospective, cluster cross-over randomised trial.

SETTING

DR in four hospitals in Canada and Austria, PARTICIPANTS: Newborn infants >28 weeks' gestation who required CC.

INTERVENTIONS

Hospitals were randomised to CC+SI or 3:1 C:V then crossed over to the other intervention.

MAIN OUTCOME MEASURE

The primary outcome was time to ROSC, defined as the duration of CC until an increase in heart rate >60/min determined by auscultation of the heart, which was maintained for 60 s. Sample size of 218 infants (109/group) was sufficient to detect a clinically important 33% reduction (282 vs 420 s of CC) in time to ROSC. Analysis was intention-to-treat.

RESULTS

Patient recruitment occurred between 19 October 2017 and 22 September 2022 and randomised 27 infants (CC+SI (n=12), 3:1 C:V (n=15), two (one per group) declined consent). All 11 infants in the CC+SI group and 12/14 infants in the 3:1 C:V group achieved ROSC in the DR. The median (IQR) time to ROSC was 90 (60-270) s and 615 (174-780) s (p=0.0502 (log rank), p=0.16 (cox proportional hazards regression)) with CC+SI and 3:1 C:V, respectively. Mortality was 2/11 (18.2%) with CC+SI versus 8/14 (57.1%) with 3:1 C:V (p=0.10 (Fisher's exact test), OR (95% CI) 0.17; (0.03 to 1.07)). The trial was stopped due to issues with ethics approval and securing trial insurance as well as funding reasons.

CONCLUSION

The time to ROSC and mortality was not statistical different between CC+SI and 3:1 C:V.

TRIAL REGISTRATION

NCT02858583.

Continuous chest compression during sustained inflation versus continuous compression with asynchronized ventilation in an infantile porcine model of severe bradycardia

Background

Recently, the American Heart Association released a statement calling for research examining the appropriate age to transition from the neonatal to pediatric cardiopulmonary resuscitation approach to resuscitation.

Aim

To compare neonatal and pediatric resuscitation approach by using either continuous chest compression with asynchronized ventilation (CCaV) or continuous chest compression superimposed with sustained inflation (CC + SI) during infant cardiopulmonary resuscitation. We hypothesized that CC + SI compared to CCaV would reduce time to return of spontaneous circulation (ROSC) in infantile piglets with asphyxia-induced bradycardic cardiac arrest.

Methods

Twenty infantile piglets (5-10 days old) were anesthetized and asphyxiated by clamping the endotracheal tube. Piglets were randomized to CC + SI or CCaV for resuscitation (n = 10/group). Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, intrathoracic pressure and respiratory parameters were continuously recorded throughout the experiment.

Main results

The median (IQR) time to ROSC with CC + SI compared to CCaV was 179 (104-447) vs 660 (189-660), p = 0.05. The number of piglets achieving ROSC with CC + SI and CCaV were 8/10 and 6/10, p = 0.628. Piglets resuscitated with CC + SI required less epinephrine compared to CCaV (p = 0.039). CC + SI increased the intrathoracic pressure throughout resuscitation (p = 0.025) and increased minute ventilation (p < 0.001), compared to CCaV. There was no difference in hemodynamic parameters between groups.

Conclusions

CC + SI improves resuscitative efforts of infantile piglets by increasing the intrathoracic pressure and minute ventilation, and thus reducing the duration of resuscitation, compared to CCaV.

Chest compressions superimposed with sustained inflation during neonatal cardiopulmonary resuscitation: are we ready for a clinical trial?

Neonates requiring cardiopulmonary resuscitation (CPR) are at risk of mortality and neurodevelopmental injury. Poor outcomes following the need for chest compressions (CCs) in the delivery room prompt the critical need for improvements in resuscitation strategies. This article explores a technique of CPR which involves CCs with sustained inflation (CC+SI). Unique features of CC+SI include (1) improved tidal volume delivery, (2) passive ventilation during compressions, (3) uninterrupted compressions and (4) improved stability of cerebral blood flow during resuscitation. CC+SI has been shown in animal studies to have improved time to return of spontaneous circulation and reduced mortality without significant increase in markers of inflammation and injury in the lung and brain, compared with standard CPR. The mechanics of CCs, rate of compressions, ventilation strategies and compression-to-ventilation ratios are detailed here. A large randomised controlled trial comparing CC+SI versus the current 3:1 compression-to-ventilation ratio is needed, given the growing evidence of its potential benefits.

Chest compressions superimposed with sustained inflations during cardiopulmonary resuscitation in asphyxiated pediatric piglets

BACKGROUND

Pediatric resuscitation guidelines recommend continuous chest compression with asynchronized ventilation (CCaV) during cardiopulmonary resuscitation. We recently described that providing a constant high distending pressure, or sustained inflation (SI) while performing continuous chest compressions (CC = CC + SI) reduces time to return of spontaneous circulation (ROSC) in neonatal and pediatric piglets with asphyxia-induced cardiac arrest.

METHODS

To determine if CC + SI compared to CCaV will improve frequency of achieving ROSC and reduce time to ROSC in asphyxiated pediatric piglets. Twenty-eight pediatric piglets (21-24 days old) were anesthetized and asphyxiated by clamping the endotracheal tube. Piglets were randomized to CC + SI or CCaV for resuscitation (n = 14/group). Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded throughout the experiment.

RESULTS

The mean(SD) duration of resuscitation was significantly reduced with CC + SI compared to CCaV with 208(190) vs. 388(258)s, p = 0.045, respectively. The number of piglets achieving ROSC with CC + SI and CCaV were 12/14 vs. 6/14, p = 0.046. Minute ventilation, end-tidal carbon dioxide, ventilation rate, and positive end expiratory pressures were also significantly improved with CC + SI.

CONCLUSIONS

CC + SI improves duration of resuscitation and increases number of piglets achieving ROSC secondary to improved minute ventilation.

IMPACT

Chest compressions superimposed with sustained inflation resulted in shorter duration of resuscitation Chest compressions superimposed with sustained inflation resulted in higher number of piglets achieving return of spontaneous circulation Further animal studies are needed to examine chest compressions superimposed with sustained inflation.

2023 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces

The International Liaison Committee on Resuscitation engages in a continuous review of new, peer-reviewed, published cardiopulmonary resuscitation and first aid science. Draft Consensus on Science With Treatment Recommendations are posted online throughout the year, and this annual summary provides more concise versions of the final Consensus on Science With Treatment Recommendations from all task forces for the year. Topics addressed by systematic reviews this year include resuscitation of cardiac arrest from drowning, extracorporeal cardiopulmonary resuscitation for adults and children, calcium during cardiac arrest, double sequential defibrillation, neuroprognostication after cardiac arrest for adults and children, maintaining normal temperature after preterm birth, heart rate monitoring methods for diagnostics in neonates, detection of exhaled carbon dioxide in neonates, family presence during resuscitation of adults, and a stepwise approach to resuscitation skills training. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, using Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces list priority knowledge gaps for further research. Additional topics are addressed with scoping reviews and evidence updates.

2023 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations: Summary From the Basic Life Support; Advanced Life Support; Pediatric Life Support; Neonatal Life Support; Education, Implementation, and Teams; and First Aid Task Forces

The International Liaison Committee on Resuscitation engages in a continuous review of new, peer-reviewed, published cardiopulmonary resuscitation and first aid science. Draft Consensus on Science With Treatment Recommendations are posted online throughout the year, and this annual summary provides more concise versions of the final Consensus on Science With Treatment Recommendations from all task forces for the year. Topics addressed by systematic reviews this year include resuscitation of cardiac arrest from drowning, extracorporeal cardiopulmonary resuscitation for adults and children, calcium during cardiac arrest, double sequential defibrillation, neuroprognostication after cardiac arrest for adults and children, maintaining normal temperature after preterm birth, heart rate monitoring methods for diagnostics in neonates, detection of exhaled carbon dioxide in neonates, family presence during resuscitation of adults, and a stepwise approach to resuscitation skills training. Members from 6 International Liaison Committee on Resuscitation task forces have assessed, discussed, and debated the quality of the evidence, using Grading of Recommendations Assessment, Development, and Evaluation criteria, and their statements include consensus treatment recommendations. Insights into the deliberations of the task forces are provided in the Justification and Evidence-to-Decision Framework Highlights sections. In addition, the task forces list priority knowledge gaps for further research. Additional topics are addressed with scoping reviews and evidence updates.

Vasopressin versus epinephrine during cardiopulmonary resuscitation of asphyxiated newborns: A study protocol for a prospective, cluster, open label, single-center, randomized controlled phase 2 trial - The VERSE-Trial

Introduction

Current neonatal resuscitation guidelines recommend the use of epinephrine during neonatal cardiopulmonary resuscitation (CPR). However, newborns receiving epinephrine continue to have high rates of mortality and neurodevelopmental disability. The infrequent need for neonatal CPR, coupled with an inability to consistently anticipate which newborn infants are at risk of requiring CPR, explains the lack of high-quality evidence (i.e., large randomized clinical trials) to better guide healthcare providers in their resuscitative effort. Therefore, we need neonatal data to determine the optimal vasopressor therapy during neonatal CPR. The current pilot trial will examine the efficacy of vasopressin versus epinephrine during CPR of asphyxiated newborn infants.

Methods and analysis

The trial will be a prospective, cluster, open label, single-center, randomized controlled trial on two alternative cardiovascular supportive medications. This study will assess the primary outcome of time to return of spontaneous circulation (ROSC) in newborns requiring CPR in the delivery room who were treated with either vasopressin (intervention) or epinephrine (control). Secondary outcomes such as infant mortality and other clinical outcome measures will also be collected. An estimated 20 newborns will be recruited, and comparisons will be made between asphyxiated infants treated with either drugs.

Ethics and dissemination

This study has been approved by the Research Ethics Board at the University of Alberta (June 16, 2023). Study findings will be published in peer-reviewed journals, presented at conferences, and communicated to relevant participants and stakeholders.Trial registration: ClinicalTrial.gov Identifier: NCT05738148. Registered February 21, 2023.

Chest compressions in newborn infants: a scoping review

AIM

The International Liaison Committee on Resuscitation Neonatal Life Support Task Force undertook a scoping review of the literature to identify evidence relating to neonatal cardiopulmonary resuscitation.

METHODS

MEDLINE complete, EMBASE and Cochrane database of Systematic reviews were searched from inception to November 2021. Two authors screened titles and abstracts and full text reviewed. Studies were eligible for inclusion if they were peer-reviewed and assessed one of five aspects of chest compression in the newborn infant including: (1) heart rate thresholds to start chest compressions (CC), (2) compression to ventilation ratio (C:V ratio), (3) CC technique, (4) oxygen use during CC and 5) feedback devices to optimise CC.

RESULTS

Seventy-four studies were included (n=46 simulation, n=24 animal and n=4 clinical studies); 22/74 were related to compression to ventilation ratios, 29/74 examined optimal technique to perform CC, 7/74 examined oxygen delivery and 15/74 described feedback devices during neonatal CC.

CONCLUSION

There were very few clinical studies and mostly manikin and animal studies. The findings either reinforced or were insufficient to change previous recommendations which included to start CC if heart rate remains <60/min despite adequate ventilation, using a 3:1 C:V ratio, the two-thumb encircling technique and 100% oxygen during CC.

Continuous compression with asynchronous ventilation improves CPR prognosis? A meta-analysis from human and animal studies

BACKGROUND

The cardiopulmonary resuscitation (CPR) compression to ventilation strategy remains controversial. We conducted a meta-analysis to compare the outcomes between continuous chest compressions CPR with asynchronous ventilation (CCC-CPR) and interrupted chest compressions CPR with synchronous ventilation (ICC-CPR) in cardiac arrest.

METHODS

PubMed, Web of Science, Embase, MEDLINE (Ovid/LWW) and the Cochrane Libraries were searched up from inception to July 31, 2022. Human and animal studies comparing CCC-CPR versus ICC-CPR were included. Outcome variables were return of spontaneous circulation (ROSC), time to ROSC, survival to discharge, 1-month survival, survival at 4 h, good neurological function, mean arterial pressure (MAP) and other clinical parameters. Jadad Scale and Newcastle-Ottawa Scale were used to assess the study quality and risk of bias.

RESULTS

The systematic search identified eight studies on humans and twelve studies on animal trials. There were no significant differences in ROSC (odd ratios [OR] 1.07; 95% confidence interval [CI]: 0.86-1.32; P = 0.55), survival to hospital discharge (OR 1.04; 95%CI 0.77-1.42; P = 0.79), 1-month survival (OR 1.07; 95%CI 0.84-1.36; P = 0.57), and good neurological outcome (OR 0.92; 95%CI 0.84-1.01, P = 0.09) between CCC-CPR and ICC-CPR in human studies. In animal trials, CCC-CPR had significantly higher rate of ROSC (OR = 1.81; 95% CI: 0.94-3.49; P = 0.07), survival at 4 h (OR 2.57; 95% CI: 1.16-5.72; P = 0.02) and MAP (mean difference [MD] 0.79, 95% CI: 0.04-1.53; P = 0.04), even though no significant differences in ROSC time, arterial potential of hydrogen (pH) and partial tension of carbon dioxide (PaCO2).

CONCLUSION

CCC-CPR did not show superiority in human outcomes compared with ICC-CPR, but its effect value was significantly increased in animal experiments. We should take the positive outcomes from animals and apply them to human models, and more physiological mechanisms need to be confirmed in CPR patients with different compression-ventilation strategies to improve the prognosis of cardiac arrest.

A Randomized, Controlled Animal Study: 21% or 100% Oxygen during Cardiopulmonary Resuscitation in Asphyxiated Infant Piglets

Background: During pediatric cardiopulmonary resuscitation (CPR), resuscitation guidelines recommend 100% oxygen (O2); however, the most effective O2 concentration for infants unknown. Aim: We aimed to determine if 21% O2 during CPR with either chest compression (CC) during sustained inflation (SI) (CC + SI) or continuous chest compression with asynchronized ventilation (CCaV) will reduce time to return of spontaneous circulation (ROSC) compared to 100% O2 in infant piglets with asphyxia-induced cardiac arrest. Methods: Piglets (20−23 days of age, weighing 6.2−10.2 kg) were anesthetized, intubated, instrumented, and exposed to asphyxia. Cardiac arrest was defined as mean arterial blood pressure < 25 mmHg with bradycardia. After cardiac arrest, piglets were randomized to CC + SI or CCaV with either 21% or 100% O2 or the sham. Heart rate, arterial blood pressure, carotid blood flow, and respiratory parameters were continuously recorded. Main results: Baseline parameters, duration, and degree of asphyxiation were not different. Median (interquartile range) time to ROSC was 107 (90−440) and 140 (105−200) s with CC + SI 21% and 100% O2, and 600 (50−600) and 600 (95−600) s with CCaV 21% and 100% O2 (p = 0.27). Overall, six (86%) and six (86%) piglets with CC + SI 21% and 100% O2, and three (43%) and three (43%) piglets achieved ROSC with CCaV 21% and 100% O2 (p = 0.13). Conclusions: In infant piglets resuscitated with CC + SI, time to ROSC reduced and survival improved compared to CCaV. The use of 21% O2 had similar time to ROSC, short-term survival, and hemodynamic recovery compared to 100% oxygen. Clinical studies comparing 21% with 100% O2 during infant CPR are warranted.

Chest compressions and medications during neonatal resuscitation

Prolonged resuscitation in neonates, although quite rare, may occur in response to profound intractable bradycardia as a result of asphyxia. In these instances, chest compressions and medications may be necessary to facilitate return of spontaneous circulation. While performing chest compressions, the two thumb method is preferred over the two finger technique, although several newer approaches are under investigation. While the ideal compression to ventilation ratio is still uncertain, a 3:1 ratio remains the recommendation by the Neonatal Resuscitation Program. Use of feedback mechanisms to optimize neonatal cardiopulmonary resuscitation (CPR) show promise and are currently under investigation. While performing optimal cardiac compressions to pump blood, use of medications to restore spontaneous circulation will likely be necessary. Current recommendations are that epinephrine, an endogenous catecholamine be used preferably intravenously or by intraosseous route, with the dose repeated every 3-5 minutes until return of spontaneous circulation. Finally, while the need for volume replacement is rare, it may be considered in instances of acute blood loss or poor response to resuscitation.

Single versus continuous sustained inflations during chest compressions and physiological-based cord clamping in asystolic lambs

BACKGROUND

The feasibility and benefits of continuous sustained inflations (SIs) during chest compressions (CCs) during delayed cord clamping (physiological-based cord clamping; PBCC) are not known. We aimed to determine whether continuous SIs during CCs would reduce the time to return of spontaneous circulation (ROSC) and improve post-asphyxial blood pressures and flows in asystolic newborn lambs.

METHODS

Fetal sheep were surgically instrumented immediately prior to delivery at ~139 days' gestation and asphyxia induced until lambs reached asystole. Lambs were randomised to either immediate cord clamping (ICC) or PBCC. Lambs then received a single SI (SIsing; 30 s at 30 cmH2O) followed by intermittent positive pressure ventilation, or continuous SIs (SIcont: 30 s duration with 1 s break). We thus examined 4 groups: ICC +SIsing, ICC +SIcont, PBCC +SIsing, and PBCC +SIcont. Chest compressions and epinephrine administration followed international guidelines. PBCC lambs underwent cord clamping 10 min after ROSC. Physiological and oxygenation variables were measured throughout.

RESULTS

The time taken to achieve ROSC was not different between groups (mean (SD) 4.3±2.9 min). Mean and diastolic blood pressure was higher during chest compressions in PBCC lambs compared with ICC lambs, but no effect of SIs was observed. SIcont significantly reduced pulmonary blood flow, diastolic blood pressure and oxygenation after ROSC compared with SIsing.

CONCLUSION

We found no significant benefit of SIcont over SIsing during CPR on the time to ROSC or on post-ROSC haemodynamics, but did demonstrate the feasibility of continuous SIs during advanced CPR on an intact umbilical cord. Longer-term studies are recommended before this technique is used routinely in clinical practice.

Assessment of optimal chest compression depth during neonatal cardiopulmonary resuscitation: a randomised controlled animal trial

AIM

The study aimed to examine the optimal anterior-posterior depth which will reduce the time to return of spontaneous circulation and improve survival during chest compressions. Asphyxiated neonatal piglets receiving chest compression resuscitated with a 40% anterior-posterior chest depth compared with 33%, 25% or 12.5% will have reduced time to return of spontaneous circulation and improved survival.

METHODS

Newborn piglets (n=8 per group) were anaesthetised, intubated, instrumented and exposed to 45 min normocapnic hypoxia followed by asphyxia and cardiac arrest. Piglets were randomly allocated to four intervention groups ('anterior-posterior 12.5% depth', 'anterior-posterior 25% depth', 'anterior-posterior 33% depth' or 'anterior-posterior 40% depth'). Chest compressions were performed using an automated chest compression machine with a rate of 90 per minute. Haemodynamic and respiratory parameters, applied compression force, and chest compression depth were continuously measured.

RESULTS

The median (IQR) time to return of spontaneous circulation was 600 (600-600) s, 135 (90-589) s, 85 (71-158)* s and 116 (63-173)* s for the 12.5%, 25%, 33% and 40% depth groups, respectively (*p<0.001 vs 12.5%). The number of piglets that achieved return of spontaneous circulation was 0 (0%), 6 (75%), 7 (88%) and 7 (88%) in the 12.5%, 25%, 33% and 40% anterior-posterior depth groups, respectively. Arterial blood pressure, central venous pressure, carotid blood flow, applied compression force, tidal volume and minute ventilation increased with greater anterior-posterior chest depth during chest compression.

CONCLUSIONS

Time to return of spontaneous circulation and survival were similar between 25%, 33% and 40% anterior-posterior depths, while 12.5% anterior-posterior depth did not result in return of spontaneous circulation or survival. Haemodynamic and respiratory parameters improved with increasing anterior-posterior depth, suggesting improved organ perfusion and oxygen delivery with 33%-40% anterior-posterior depth.

TRIAL REGISTRATION NUMBER

PTCE0000193.

Relationship between psychological characteristics, personality traits, and training on performance in a neonatal resuscitation scenario: A machine learning based analysis

BACKGROUND

In life-threatening emergency events, prompt decision-making and accurate reactions are essential for saving a human's life. Some of these skills can be improved by regular simulation trainings. However, besides these factors, individual characteristics may play a significant role in the patients' outcome after a resuscitation event. This study aimed to differentiate personality characteristics of team members who take responsibility for their actions, contextualizing the effect of training on resuscitation performance.

METHODS

Six hundred and two third-year medical students were asked to answer psychological and personality questionnaires. Fifty-five of them performed in a neonatal simulation resuscitation scenario. To assess participants' performances in the NLS scenario, we used a scenario-based designed NLS checklist. A machine learning design was utilized to better understand the interaction of psychological characteristics and training. The first model aimed to understand how to differentiate between people who take responsibility for their actions vs. those who do not. In a second model, the goal was to understand the relevance of training by contextualizing the effect of training to other important psychological and personality characteristics like locus of control, anxiety, emotion regulation, openness to experience, conscientiousness, extraversion, agreeableness, and neuroticism.

RESULTS

No statistically significant differences were found for psychological characteristics between the training group and the no training group. However, as expected, differences were noted in favor of the training group for performance and within gender for psychological characteristics. When correcting for all these information in a model, anxiety and gender were the most important factors associated with taking responsibility for an action, while training was the only relevant factor in explaining performance during a neonatal resuscitation scenario.

CONCLUSION

Training had a significantly stronger effect on performance in medical students in a neonatal resuscitation scenario than individual characteristics such as demographics, personality, and trait anxiety.

Sustained Inflation During Chest Compression: A New Technique of Pediatric Cardiopulmonary Resuscitation That Improves Recovery and Survival in a Pediatric Porcine Model

Background

Chest compression (CC) during sustained inflations (CC+SI) compared with CC with asynchronized ventilation (CCaV) during cardiopulmonary resuscitation in asphyxiated pediatric piglets will reduce time to return of spontaneous circulation (ROSC).

Methods and Results

Piglets (20–23 days of age, weighing 6.2–10.2 kg) were anesthetized, intubated, instrumented, and exposed to asphyxia. Cardiac arrest was defined as mean arterial blood pressure <25 mm Hg with bradycardia. After cardiac arrest, piglets were randomized to CC+SI (n=12) or CCaV (n=12) or sham (n=8). Sham‐operated animals had no asphyxia. Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded. There were no differences in baseline parameters or the duration and degree of asphyxiation. Median (interquartile range) Time to ROSC was 248 (41–346) seconds compared with 720 (167–720) seconds in the CC+SI group and CCaV group, respectively (P=0.0292). There was a 100% higher rate of ROSC in the CC+SI group versus CCaV group, with 10 (83%) versus 5 (42%) achieving ROSC (P=0.089), respectively. Piglets in the CC+SI and CCaV groups received intravenous epinephrine boluses to achieve ROSC (8/12 versus 10/12 P=0.639). There was a significantly higher minute ventilation in the CC+SI group, which was secondary to a 5‐fold increase in the number of inflations per minute and a 1.5‐fold increase in tidal volume.

Conclusions

CC+SI reduced time to ROSC and improved survival compared with using CCaV. CC+SI allowed passive ventilation of the lung while providing chest compressions. This technique warrants further studies to examine the potential to improve outcomes in pediatric patients with cardiac arrest.

Registration

URL: https://www.preclinicaltrials.eu; Unique identifier: PCTE0000152.

Continuous chest compressions with asynchronous ventilation improve survival in a neonatal swine model of asphyxial cardiac arrest

BACKGROUND

Guidelines for neonatal resuscitation recommend a 3:1 compression to ventilation ratio. However, this recommendation is based on expert opinion and consensus rather than strong scientific evidence. Our primary aim was to assess whether continuous chest compressions with asynchronous ventilations would increase return of spontaneous circulation (ROSC) rate and survival compared to the 3:1 chest compression to ventilation ratio.

METHODS

This was a prospective, randomized, laboratory study. Twenty male Landrace-Large White pigs, aged 1-4 days with an average weight 1.650 ± 228.3 g were asphyxiated and left untreated until heart rate was less than 60 bpm or mean arterial pressure was below 15 mmHg. Animals were then randomly assigned to receive either continuous chest compressions with asynchronous ventilations (n = 10), or standard (3:1) chest compression to ventilation ratio (n = 10). Heart rate and arterial pressure were assessed every 30 s during cardiopulmonary resuscitation (CPR) until ROSC or asystole. All animals with ROSC were monitored for 4 h.

RESULTS

Coronary perfusion pressure (CPP) at 30 s of CPR was significantly higher in the experimental group (45.7 ± 16.9 vs. 21.8 ± 6 mmHg, p < 0.001) and remained significantly elevated throughout the experiment. End-tidal carbon dioxide (ETCO₂) was also significantly higher in the experimental group throughout the experiment (23.4 ± 5.6 vs. 14.7 ± 5.9 mmHg, p < 0.001). ROSC was observed in six (60%) animals treated with 3:1 compression to ventilation ratio and nine (90%) animals treated with continuous chest compressions and asynchronous ventilation (p = 0.30). Time to ROSC was significantly lower in the experimental group (30 (30-30) vs. 60 (60-60) sec, p = 0.021). Of note, 7 (77.8%) animals in the experimental group and 1 (16.7%) animal in the control group achieved ROSC after 30 s (0.02). At 4 h, 2 (20%) animals survived in the control group compared to 7 (70%) animals in the experimental group (p = 0.022).

CONCLUSION

Continuous chest compressions with asynchronous ventilations significantly improved CPP, ETCO₂, time to ROSC, ROSC at 30 s and survival in a porcine model of neonatal resuscitation.

Is Chest Compression Superimposed with Sustained Inflation during Cardiopulmonary Resuscitation an Alternative to 3:1 Compression to Ventilation Ratio in Newborn Infants?

Approximately 0.1% for term and 10-15% of preterm infants receive chest compression (CC) in the delivery room, with high incidence of mortality and neurologic impairment. The poor prognosis associated with receiving CC in the delivery room has raised concerns as to whether specifically-tailored cardiopulmonary resuscitation methods are needed. The current neonatal resuscitation guidelines recommend a 3:1 compression:ventilation ratio; however, the most effective approach to deliver chest compression is unknown. We recently demonstrated that providing continuous chest compression superimposed with a high distending pressure or sustained inflation significantly reduced time to return of spontaneous circulation and mortality while improving respiratory and cardiovascular parameters in asphyxiated piglet and newborn infants. This review summarizes the current available evidence of continuous chest compression superimposed with a sustained inflation.

Sustained Lung Inflations During Neonatal Resuscitation at Birth: A Meta-analysis

CONTEXT

The International Liaison Committee on Resuscitation prioritized review of sustained inflation (SI) of the lung at birth.

OBJECTIVE

To complete a systematic review and meta-analysis comparing strategies using 1 or more SI ≥1 second with intermittent inflations <1 second for newborns at birth.

DATA SOURCES

Medline, Embase, and Evidence-Based Medicine Reviews were searched from January 1, 1946, to July 20, 2020.

STUDY SELECTION

Studies were selected by pairs of independent reviewers in 2 stages.

DATA EXTRACTION

Reviewers extracted data, appraised risk of bias, and assessed certainty of evidence for each outcome.

RESULTS

Ten trials enrolling 1502 preterm newborns were included. Five studies included newborns who did not receive assisted ventilation at the outset. There were no differences between SI and control groups for death before discharge or key morbidities. For death within the first 2 days, comparing SI with the controls, risk ratio was 2.42 (95% confidence interval = 1.15-5.09). In subgroup analysis of preterm infants ≤28 + 0 weeks' gestation, for death before discharge, risk ratio was 1.38 (95% confidence interval = 1.00-1.91). Together, these findings suggest the potential for harm of SI.

LIMITATIONS

The certainty of evidence was very low for death in the delivery room and low for all other outcomes.

CONCLUSIONS

In this systematic review, we did not find benefit in using 1 or more SI >5 seconds for preterm infants at birth. SI(s) may increase death before discharge among the subgroup born ≤28 + 0 weeks' gestation. There is insufficient evidence to determine the likely effect of SI(s) on other key morbidities.

Return of Spontaneous Circulation Depends on Cardiac Rhythm During Neonatal Cardiac Arrest in Asphyxiated Newborn Animals

Objective: Pulseless electrical activity (PEA) occurs in asphyxiated newborn piglets and infants. We aimed to examine whether different cardiac rhythms (asystole, bradycardia, PEA) affects the resuscitation outcomes during continuous chest compressions (CC) during sustained inflations (CC+SI). Design: This study is a secondary analysis of four previous randomized controlled animal trials that compared CC+SI with different CC rate (90 or 120/min), SI duration (20 or 60 s), peak inflation pressure (10, 20, or 30 cmH₂O), and oxygen concentration (18, 21, or 100%). Setting and Subjects: Sixty-six newborn mixed breed piglets (1-3 days of age, weight 1.7-2.4 kg) were obtained on the day of experimentation from the University Swine Research Technology Center. Interventions: In all four studies, piglets were randomized into intervention or sham. Piglets randomized to "intervention" underwent both hypoxia and asphyxia, whereas, piglets randomized to "sham" received the same surgical protocol, stabilization, and equivalent experimental periods without hypoxia and asphyxia. Measurements: To compare differences in asphyxiation time, time to return of spontaneous circulation (ROSC), hemodynamics, and survival rate in newborn piglets with asystole, bradycardia or PEA. Main Results: Piglets with PEA (n = 29) and asystole (n = 13) had a significantly longer asphyxiation time and time to ROSC vs. bradycardia (n = 24). Survival rates were similar between all groups. Compared to their baseline, mean arterial pressure and carotid blood flow were significantly lower 4 h after resuscitation in all groups, while being significantly higher in the bradycardia group. Conclusion: This study indicates that cardiac rhythm before resuscitation influences the time to ROSC and hemodynamic recovery after ROSC.

Delivery Room Management of Asphyxiated Term and Near-Term Infants

Approximately 800,000 newborns die annually due to birth asphyxia. The resuscitation of asphyxiated term newly born infants often occurs unexpected and is challenging for healthcare providers as it demands experience and knowledge in neonatal resuscitation. Current neonatal resuscitation guidelines often focus on resuscitation of extremely and/or very preterm infants; however, the recommendations for asphyxiated term newborn infants differ in some aspects to those for preterm infants (i.e., respiratory support, supplemental oxygen, and temperature management). Since the update of the neonatal resuscitation guidelines in 2015, several studies examining various resuscitation approaches to improve the outcome of asphyxiated infants have been published. In this review, we discuss current recommendations and recent findings and provide an overview of delivery room management of asphyxiated term newborn infants.

Sustained inflation with 21% versus 100% oxygen during cardiopulmonary resuscitation of asphyxiated newborn piglets - A randomized controlled animal study

BACKGROUND

Current neonatal resuscitation guidelines recommend using 100% oxygen during chest compressions (CC), however the most effective oxygen concentration during cardiopulmonary resuscitation remains controversial.

AIM

In term newborn piglets with asphyxia-induced cardiac arrest does 21% oxygen compared to 100% oxygen during resuscitation using CC during sustained inflation (SI; CC + SI) will have a reduced time to return of spontaneous circulation (ROSC).

INTERVENTION AND MEASUREMENTS

Twenty-two mixed breed piglets (1-3 days old, 1.7-2.4 kg), were obtained on the day of the experiment and anesthetized, intubated, instrumented, and exposed to 30-min normocapnic hypoxia followed by asphyxia. Piglets were resuscitated using CC + SI and randomized to 21% oxygen (n = 8) or 100% oxygen (n = 8). Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded throughout the experiment.

MAIN RESULTS

Baseline parameters were similar between 21% and 100% oxygen groups. There was no difference in asphyxiation (duration and degree) between groups. Time to ROSC was similar between 21% and 100% oxygen groups: median (interquartile range - IQR) 80 (70-190)sec vs. 90 (70-324)sec, (p = 0.56). There was no significant difference in the rate of ROSC between 21% and 100% oxygen groups: 7/8 (88%) vs. 5/8 (63%), (p = 0.569). All piglets that achieved ROSC survived to four hours post-resuscitation. Hemodynamics and regional perfusion were not significantly different between groups.

CONCLUSIONS

In term newborn piglets resuscitated by CC + SI, the use of 21% oxygen resulted in a similar time to ROSC, short-term survival, and hemodynamic recovery compared to 100% oxygen.

Effects of sustained inflation pressure during neonatal cardiopulmonary resuscitation of asphyxiated piglets

Background

Sustained inflation (SI) during chest compression (CC = CC+SI) has been recently shown as an alternative method during cardiopulmonary resuscitation in neonates. However, the optimal peak inflation pressure (PIP) of SI during CC+SI to improve ROSC and hemodynamic recovery is unknown.

Objective

To examine if different PIPs of SI during CC+SI will improve ROSC and hemodynamic recovery in severely asphyxiated piglets.

Methods

Twenty-nine newborn piglets (1–3 days old) were anesthetized, intubated, instrumented and exposed to 30-min normocapnic hypoxia followed by asphyxia. Piglets were randomized into four groups: CC+SI with a PIP of 10 cmH₂O (CC+SI_PIP_10, n = 8), a PIP of 20 cmH₂O (CC+SI_PIP_20, n = 8), a PIP of 30 cmH₂O (CC+SI_PIP_30, n = 8), and a sham-operated control group (n = 5). Heart rate, arterial blood pressure, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded throughout the experiment.

Results

Baseline parameters were similar between all groups. There was no difference in asphyxiation (duration and degree) between intervention groups. PIP correlated positively with tidal volume (V_T) and inversely with exhaled CO₂ during cardiopulmonary resuscitation. Time to ROSC and rate of ROSC were similar between piglets resuscitated with CC+SI_PIP_10, CC+SI_PIP_20, and CC+SI_PIP_30 cmH₂O: median (IQR) 75 (63–193) sec, 94 (78–210) sec, and 85 (70–90) sec; 5/8 (63%), 7/8 (88%), and 3/8 (38%) (p = 0.56 and p = 0.12, respectively). All piglets that achieved ROSC survived to four hours post-resuscitation. Piglets resuscitated with CC+SI_PIP_30 cmH₂O exhibited increased concentrations of pro-inflammatory cytokines interleukin-1β and tumour necrosis factor-α in the frontoparietal cerebral cortex (both p<0.05 vs. sham-operated controls).

Conclusion

In asphyxiated term newborn piglets resuscitated by CC+SI, the use of different PIPs resulted in similar time to ROSC, but PIP at 30 cmH₂O showed a larger V_T delivery, lower exhaled CO₂ and increased tissue inflammatory markers in the brain.

Sustained Inflation vs Standard Resuscitation for Preterm Infants: A Systematic Review and Meta-analysis

IMPORTANCE

Most preterm infants require respiratory support to establish lung aeration after birth. Intermittent positive pressure ventilation and continuous positive airway pressure are standard therapies. An initial sustained inflation (inflation time >5 seconds) is a widely practiced alternative strategy.

OBJECTIVE

To conduct a systematic review and meta-analysis of sustained inflation vs intermittent positive pressure ventilation and continuous positive airway pressure for the prevention of hospital mortality and morbidity for preterm infants.

DATA SOURCES

MEDLINE (through PubMed), Embase, the Cumulative Index of Nursing and Allied Health Literature, and the Cochrane Central Register of Controlled Trials were searched through June 24, 2019.

STUDY SELECTION

Randomized clinical trials of preterm infants born at less than 37 weeks' gestation that compared sustained inflation (inflation time >5 seconds) vs standard resuscitation with either intermittent positive pressure ventilation or continuous positive airway pressure were included. Studies including other cointerventions were excluded.

DATA EXTRACTION AND SYNTHESIS

Two reviewers assessed the risk of bias of included studies. Meta-analysis of pooled outcome data used a fixed-effects model specific to rarer events. Subgroups were based on gestational age and study design (rescue vs prophylactic sustained inflation).

MAIN OUTCOMES AND MEASURES

Death before hospital discharge.

RESULTS

Nine studies recruiting 1406 infants met inclusion criteria. Death before hospital discharge occurred in 85 of 736 infants (11.5%) treated with sustained inflation and 62 of 670 infants (9.3%) who received standard therapy for a risk difference of 3.6% (95% CI, -0.7% to 7.9%). Although analysis of the primary outcome identified important heterogeneity based on gestational age subgroups, the 95% CI for the risk difference included 0 for each individual gestational age subgroup. There was no difference in the primary outcome between subgroups based on study design. Sustained inflation was associated with increased risk of death in the first 2 days after birth (risk difference, 3.1%; 95% CI, 0.9%-5.3%). No differences in the risk of other secondary outcomes were identified. The quality-of-evidence assessment was low owing to risk of bias and imprecision.

CONCLUSIONS AND RELEVANCE

There was no difference in the risk of the primary outcome of death before hospital discharge, and there was no evidence of efficacy for sustained inflation to prevent secondary outcomes. These findings do not support the routine use of sustained inflation for preterm infants after birth.

Sustained versus standard inflations during neonatal resuscitation to prevent mortality and improve respiratory outcomes

BACKGROUND

At birth, infants' lungs are fluid-filled. For newborns to have a successful transition, this fluid must be replaced by air to enable gas exchange. Some infants are judged to have inadequate breathing at birth and are resuscitated with positive pressure ventilation (PPV). Giving prolonged (sustained) inflations at the start of PPV may help clear lung fluid and establish gas volume within the lungs.

OBJECTIVES

To assess the benefits and harms of an initial sustained lung inflation (SLI) (> 1 second duration) versus standard inflations (≤ 1 second) in newborn infants receiving resuscitation with intermittent PPV.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 3), MEDLINE via PubMed (1966 to 1 April 2019), Embase (1980 to 1 April 2019), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 1 April 2019). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles to identify randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing initial sustained lung inflation (SLI) versus standard inflations given to infants receiving resuscitation with PPV at birth.

DATA COLLECTION AND ANALYSIS

We assessed the methodological quality of included trials using Cochrane Effective Practice and Organisation of Care Group (EPOC) criteria (assessing randomisation, blinding, loss to follow-up, and handling of outcome data). We evaluated treatment effects using a fixed-effect model with risk ratio (RR) for categorical data; and mean standard deviation (SD), and weighted mean difference (WMD) for continuous data. We used the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Ten trials enrolling 1467 infants met our inclusion criteria. Investigators in nine trials (1458 infants) administered sustained inflation with no chest compressions. Use of sustained inflation had no impact on the primary outcomes of this review: mortality in the delivery room (typical RR 2.66, 95% confidence interval (CI) 0.11 to 63.40 (I² not applicable); typical RD 0.00, 95% CI -0.02 to 0.02; I² = 0%; 5 studies, 479 participants); and mortality during hospitalisation (typical RR 1.09, 95% CI 0.83 to 1.43; I² = 42%; typical RD 0.01, 95% CI -0.02 to 0.04; I² = 24%; 9 studies, 1458 participants). The quality of the evidence was low for death in the delivery room because of limitations in study design and imprecision of estimates (only one death was recorded across studies). For death before discharge the quality was moderate: with longer follow-up there were more deaths (n = 143) but limitations in study design remained. Among secondary outcomes, duration of mechanical ventilation was shorter in the SLI group (mean difference (MD) -5.37 days, 95% CI -6.31 to -4.43; I² = 95%; 5 studies, 524 participants; low-quality evidence). Heterogeneity, statistical significance, and magnitude of effects of this outcome are largely influenced by a single study at high risk of bias: when this study was removed from the analysis, the size of the effect was reduced (MD -1.71 days, 95% CI -3.04 to -0.39; I² = 0%). Results revealed no differences in any of the other secondary outcomes (e.g. risk of endotracheal intubation outside the delivery room by 72 hours of age (typical RR 0.91, 95% CI 0.79 to 1.04; I² = 65%; 5 studies, 811 participants); risk of surfactant administration during hospital admission (typical RR 0.99, 95% CI 0.91 to 1.08; I² = 0%; 9 studies, 1458 participants); risk of chronic lung disease (typical RR 0.99, 95% CI 0.83 to 1.18; I² = 0%; 4 studies, 735 participants); pneumothorax (typical RR 0.89, 95% CI 0.57 to 1.40; I² = 34%; 8 studies, 1377 infants); or risk of patent ductus arteriosus requiring pharmacological treatment (typical RR 0.99, 95% CI 0.87 to 1.12; I² = 48%; 7 studies, 1127 infants). The quality of evidence for these secondary outcomes was moderate (limitations in study design ‒ GRADE) except for pneumothorax (low quality: limitations in study design and imprecision of estimates ‒ GRADE). We could not perform any meta-analysis in the comparison of the use of initial sustained inflation versus standard inflations in newborns receiving resuscitation with chest compressions because we identified only one trial for inclusion (a pilot study of nine preterm infants).

AUTHORS' CONCLUSIONS

Our meta-analysis of nine studies shows that sustained lung inflation without chest compression was not better than intermittent ventilation for reducing mortality in the delivery room (low-quality evidence ‒ GRADE) or during hospitalisation (moderate-quality evidence ‒ GRADE), which were the primary outcomes of this review. However, the single largest study, which was well conducted and had the greatest number of enrolled infants, was stopped early for higher mortality rate in the sustained inflation group. When considering secondary outcomes, such as rate of intubation, rate or duration of respiratory support, or bronchopulmonary dysplasia, we found no benefit of sustained inflation over intermittent ventilation (moderate-quality evidence ‒ GRADE). Duration of mechanical ventilation was shortened in the SLI group (low-quality evidence ‒ GRADE); this result should be interpreted cautiously, however, as it might have been influenced by study characteristics other than the intervention. There is no evidence to support the use of sustained inflation based on evidence from our review.

Chest Compression in Neonatal Cardiac Arrest: Cerebral Blood Flow Measurements in Experimental Models

The main aim of this paper was to provide an overview of studies that measured cerebral blood flow (CBF), directly or indirectly, during chest compression (CC) in neonatal animals. Our main research question was: how did different ways of performing CC influence CBF. We also aimed to discuss strengths and limitations of different methods for measuring CBF. Based on a search in Medline Ovid, we identified three studies in piglets that investigated different CC:ventilation (C:V) ratios, as well as three piglet studies investigating continuous CC with asynchronous ventilation. CBF was measured indirectly in all studies by means of carotid artery (CA) flow and regional cerebral oxygenation (rcSO₂). The CA provides flow to the brain, but also to extracerebral structures. The relative sizes of the internal and external carotid arteries and their flow distributions are species-dependent. rcSO₂ is a non-invasive continuous measure, but does not only reflect CBF, but also cerebral blood volume and the metabolic rate of oxygen in the brain. Continuous CC with asynchronous ventilation at a CC rate of 120/min, and combining CC with a sustained inflation (four studies in piglets and one in lambs) provided a faster CBF recovery compared with the standard 3:1 C:V approach.

Asphyxiated Female and Male Newborn Piglets Have Similar Outcomes With Different Cardiopulmonary Resuscitation Interventions

Background: Male newborns have a greater risk of poor cardiovascular and respiratory outcomes compared to females. The mechanisms associated with the "male disadvantage" remains unclear. We have previously shown no difference between male and female newborn piglets during hypoxia, asphyxia, resuscitation, and post-resuscitation recovery. However, it is unknown if there are differences in resuscitation outcomes between males and females during different cardiopulmonary resuscitation techniques. Intervention and Measurements: Secondary analysis of 184 term newborn mixed breed duroc piglets (1-3 days of age, weighing 2.0 (0.2) kg) from seven different studies, which were exposed to 30-50 min of normocapnic hypoxia followed by asphyxia until asystole. This was followed by cardiopulmonary resuscitation. For the analysis, piglets were divided into male and female groups, as well as resuscitation technique groups (sustained inflation, 3:1 compression-to-ventilation ratio, or asynchronous ventilations during chest compressions). Cardiac function, carotid blood flow, and cerebral oxygenation were continuously recorded throughout the experiment. Main results: Regardless of resuscitation technique, there was no significant difference between males and females in the number achieving return of spontaneous circulation (ROSC) [95/123 (77%) vs. 48/61 (79%)], the time to achieve ROSC [112 (80-185) s vs. 110 (77-186) s], and the 4-h survival rate [81/95 (85%) vs. 40/48 (83%)]. Levels of the injury markers interleukin (IL)-1ß, IL-6, IL-8, and tumor necrosis factor-α in frontoparietal cortex tissue homogenates were similar between males and females. Conclusions: Regardless of resuscitation technique, there was no significant effect of sex on resuscitation outcome, survival, and hemodynamic recovery in asphyxiated newborn piglets.

Ventilation with 18, 21, or 100% Oxygen during Cardiopulmonary Resuscitation of Asphyxiated Piglets: A Randomized Controlled Animal Trial

BACKGROUND

In previous piglet experiments of profound asphyxia and cardiac arrest, recovery was similar when 21 and 100% oxygen were used for positive pressure ventilation (PPV). There was no consistent reduction in inflammation and oxidative stress in piglets ventilated with 21 or 100% oxygen.

OBJECTIVES

We aimed to investigate hypoxic resuscitation, i.e., PPV with 18% oxygen, in profoundly asphyxiated piglets with cardiac arrest. We hypothesized that resuscitation with 18% oxygen would result in less inflammation and oxidative stress compared to 21 or 100% oxygen.

METHOD

Twenty-four piglets were exposed to 30 min of normocapnic hypoxia followed by asphyxia until asystole. The piglets were randomized to PPV with 18% oxygen (n = 8), 21% oxygen (n = 8), or 100% oxygen (n = 8), and resuscitated with chest compressions and intravenous epinephrine. Return of spontaneous circulation (ROSC) was defined as an unassisted heart rate ≥100 bpm for 15 s. Lactate, GSH (total glutathione), GSSG (oxidized glutathione), and GSSG/GSH ratio were measured in myocardial and frontoparietal cortex homogenates. Interleukin (IL)-8, IL-6, IL-1β and tumor necrosis factor α were measured in frontoparietal cortex homogenates.

RESULTS

There was no difference in time to ROSC or inflammation and oxidative stress in the 3 oxygen groups.

CONCLUSIONS

Resuscitation with 18% oxygen did not result in differences in inflammation and oxidative stress when compared to 21 or 100% oxygen.

Novel interventions to reduce oxidative-stress related brain injury in neonatal asphyxia

Perinatal asphyxia-induced brain injury may present as hypoxic-ischemic encephalopathy in the neonatal period, and disability including cerebral palsy in the long term. The brain injury is secondary to both the hypoxic-ischemic event and the reoxygenation-reperfusion following resuscitation. Early events in the cascade of brain injury can be classified as either inflammation or oxidative stress through the generation of free radicals. The objective of this paper is to present efforts that have been made to limit the oxidative stress associated with hypoxic-ischemic encephalopathy. In the acute phase of ischemia/hypoxia and reperfusion/reoxygenation, the outcomes of asphyxiated infants can be improved by optimizing the initial delivery room stabilization. Interventions include limiting oxygen exposure, and shortening the time to return of spontaneous circulation through improved methods for supporting hemodynamics and ventilation. Allopurinol, melatonin, noble gases such as xenon and argon, and magnesium administration also target the acute injury phase. Therapeutic hypothermia, N-acetylcysteine2-iminobiotin, remote ischemic postconditioning, cannabinoids and doxycycline target the subacute phase. Erythropoietin, mesenchymal stem cells, topiramate and memantine could potentially limit injury in the repair phase after asphyxia. To limit the injurious biochemical processes during the different stages of brain injury, determination of the stage of injury in any particular infant remains essential. Currently, therapeutic hypothermia is the only established treatment in the subacute phase of asphyxia-induced brain injury. The effects and side effects of oxidative stress reducing/limiting medications may however be difficult to predict in infants during therapeutic hypothermia. Future neuroprotection in asphyxiated infants may indeed include a combination of therapies. Challenges include timing, dosing and administration route for each neuroprotectant.

Chest Compressions During Sustained Inflation During Cardiopulmonary Resuscitation in Newborn Infants Translating Evidence From Animal Studies to the Bedside

Newborn infants receiving chest compressions in the delivery room have a high incidence of mortality (41%) and short-term neurological morbidity (e.g., 57% hypoxic-ischemic encephalopathy and seizures). Furthermore, infants who have no signs of life at 10 min despite chest compressions have 83% mortality, with 93% of survivors experiencing moderate-to-severe disability. The poor prognosis associated with receiving chest compressions in the delivery room raises questions as to whether improved cardiopulmonary resuscitation methods specifically tailored to the newborn could improve outcomes. Combining chest compressions during sustained inflation (CC+SI) has recently been shown to improve morbidity and mortality outcomes during cardiopulmonary resuscitation. Overall, CC+SI accomplishes the following: 1) significantly reduces time to return of spontaneous circulation, mortality, and epinephrine administration, and improves systemic and regional hemodynamic recovery; 2) significantly increases tidal volume and minute ventilation, and therefore alveolar oxygen delivery; 3) allows for passive ventilation during chest compression; and 4) does not increase lung or brain injury markers compared with the current standard of using 3:1 compression:ventilation ratio. A randomized trial comparing CC+SI versus a 3:1 compression:ventilation ratio during cardiopulmonary resuscitation in the delivery room is therefore warranted.

The SURV1VE trial-sustained inflation and chest compression versus 3:1 chest compression-to-ventilation ratio during cardiopulmonary resuscitation of asphyxiated newborns: study protocol for a cluster randomized controlled trial

Background

The need for cardiopulmonary resuscitation (CPR) is often unexpected, and the infrequent use of CPR in the delivery room (DR) limits the opportunity to perform rigorous clinical studies to determine the best method for delivering chest compression (CC) to newborn infants. The current neonatal resuscitation guidelines recommend using a coordinated 3:1 compression-to-ventilation (C:V) ratio (CC at a rate of 90/min and ventilations at a rate of 30/min). In comparison, providing CC during a sustained inflation (SI) (CC + SI) significantly improved hemodynamics, minute ventilation, and time to return of spontaneous circulation (ROSC) compared to 3:1 C:V ratio in asphyxiated piglets. Similarly, a small pilot trial in newborn infants showed similar results. Until now no study has examined different CC techniques during neonatal resuscitation in asphyxiated newborn infants in the DR. To date, no trial has been performed to directly compare CC + SI and 3:1 C:V ratio in the DR during CPR of asphyxiated newborn infants.

Methods

This is a large, international, multi-center, prospective, unblinded, cluster randomized controlled trial in asphyxiated newborn infants at birth. All term and preterm infants > 28^+ 0 by best obstetrical estimate who require CPR at birth due to bradycardia (< 60/min) or asystole are eligible. The primary outcome of this study is to compare the time to ROSC in infants born > 28^+ 0 weeks’ gestational age with bradycardia (< 60/min) or asystole immediately after birth who receive either CC + SI or 3:1 C:V ratio as the CPR strategy.

Discussion

Morbidity and mortality rates are extremely high for newborns requiring CC. We believe the combination of simultaneous CC and SI during CPR has the potential to significantly improve ROSC and survival. In addition, we believe that CC + SI might improve respiratory and hemodynamic parameters and potentially minimize morbidity and mortality in newborn infants. In addition, this will be the first randomized controlled trial to examine CC in the newborn period.

Trial registration

ClinicalTrials.gov, NCT02858583. Registered on 8 August 2016

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3240-8) contains supplementary material, which is available to authorized users.

Chest Compressions in the Delivery Room

Annually, an estimated 13–26 million newborns need respiratory support and 2–3 million newborns need extensive resuscitation, defined as chest compression and 100% oxygen with or without epinephrine in the delivery room. Despite such care, there is a high incidence of mortality and neurologic morbidity. The poor prognosis associated with receiving chest compression alone or with medications in the delivery room raises questions as to whether improved cardiopulmonary resuscitation methods specifically tailored to the newborn could improve outcomes. This review discusses the current recommendations, mode of action, different compression to ventilation ratios, continuous chest compression with asynchronous ventilations, chest compression and sustained inflation optimal depth, and oxygen concentration during cardiopulmonary resuscitation.

Evidence for vasopressors during cardiopulmonary resuscitation in newborn infants

An estimated 0.1% of term infants and up to 15% of preterm infants (2-3 million worldwide) need extensive resuscitation, defined as chest compression and 100% oxygen with or without epinephrine in the delivery room. Despite these interventions, infants receiving extensive resuscitation in the DR have a high incidence of mortality and neurologic morbidity. Successful resuscitation from neonatal cardiac arrest requires the delivery of high-quality chest compression using the most effective vasopressor with the optimal dose, timing, and route of administration during CPR. Current neonatal resuscitation guidelines recommend administration of epinephrine once CPR has started at a dose of 0.01-0.03 mg/kg preferably given intravenously, with repeated doses every 3-5 min until return of spontaneous circulation. This review examines the current evidence for epinephrine and alternative vasopressors during neonatal cardiopulmonary resuscitation.

What to do if A + B doesn't work

The majority of newborn resuscitations require very little beyond simple airway management and assisted ventilation. If cardiovascular collapse is serious enough to warrant additional support, resuscitation algorithms recommend moving to chest compressions and then on to medications and possibly volume replacement if vital signs remain marginal or absent. The evidence base upon which this part of the neonatal resuscitation algorithm is structured is sparse. Chest compressions and medications are rare interventions that do not lend themselves easily to clinical trials. Slowly but surely, however, the genesis of an empirical evidence base for this part of the algorithm is beginning to appear.

Comparison of Different Compression to Ventilation Ratios (2: 1, 3: 1, and 4: 1) during Cardiopulmonary Resuscitation in a Porcine Model of Neonatal Asphyxia

BACKGROUND

High-quality chest compression is essential during neonatal cardiopulmonary resuscitation (CPR). However, the optimal compression to ventilation ratio (C:V) that should be used during neonatal CPR to optimize coronary and cerebral perfusion while providing adequate ventilation remains unknown.

OBJECTIVE

We hypothesized that different C:V ratios (e.g., 2: 1 or 4: 1) will reduce the time to return of spontaneous circulation (ROSC) in severely asphyxiated piglets.

METHODS

Thirty-one newborn piglets (1-4 days old) were anesthetized, intubated, instrumented, and exposed to 50-min normocapnic hypoxia followed by asphyxia. Piglets were randomized into 4 groups: 2: 1 (n = 8), 3: 1 (n = 8), 4: 1 (n = 8) C:V ratio, or a sham group (n = 7). Cardiac function, carotid blood flow, cerebral oxygenation, and respiratory parameters were continuously recorded throughout the experiment.

RESULTS

Thirty-one piglets were included in the study, and there was no difference in the duration of asphyxia or the degree of asphyxiation (as indicated by pH, PaCO2, and lactate) among the different groups. The median (IQR) time to ROSC was similar between the groups with 127 (82-210), 96 (88-126), and 119 (83-256) s in the 2: 1, 3: 1, and 4: 1 C:V ratio groups, respectively (p = 0.67 between groups). Similarly, there was no difference in 100% oxygen requirement or epinephrine administration between the experimental groups.

CONCLUSIONS

Different C:V ratios resulted in similar ROSC, mortality, oxygen, and epinephrine administration during resuscitation in a porcine model of neonatal asphyxia.

Ventilation Strategies during Neonatal Cardiopulmonary Resuscitation

Approximately, 10-20% of newborns require breathing assistance at birth, which remains the cornerstone of neonatal resuscitation. Fortunately, the need for chest compression (CC) or medications in the delivery room (DR) is rare. About 0.1% of term infants and up to 15% of preterm infants receive these interventions, this will result in approximately one million newborn deaths annually worldwide. In addition, CC or medications (epinephrine) are more frequent in the preterm population (~15%) due to birth asphyxia. A recent study reported that only 6 per 10,000 infants received epinephrine in the DR. Further, the study reported that infants receiving epinephrine during resuscitation had a high incidence of mortality (41%) and short-term neurologic morbidity (57% hypoxic-ischemic encephalopathy and seizures). A recent review of newborns who received prolonged CC and epinephrine but had no signs of life at 10 min following birth noted 83% mortality, with 93% of survivors suffering moderate-to-severe disability. The poor prognosis associated with receiving CC alone or with medications in the DR raises questions as to whether improved cardiopulmonary resuscitation methods specifically tailored to the newborn could improve outcomes.