Use of high-dose epinephrine and sodium bicarbonate during neonatal resuscitation: is there proven benefit?

Masked Randomized Trial of Epinephrine versus Vasopressin in an Ovine Model of Perinatal Cardiac Arrest

BACKGROUND

Current neonatal resuscitation guidelines recommend the use of epinephrine for bradycardia/arrest not responding to ventilation and chest compressions. Vasopressin is a systemic vasoconstrictor and is more effective than epinephrine in postnatal piglets with cardiac arrest. There are no studies comparing vasopressin with epinephrine in newly born animal models with cardiac arrest induced by umbilical cord occlusion. Objective: To compare the effect of epinephrine and vasopressin on the incidence and time to return of spontaneous circulation (ROSC), hemodynamics, plasma drug levels, and vasoreactivity in perinatal cardiac arrest. Design/Methods: Twenty-seven term fetal lambs in cardiac arrest induced by cord occlusion were instrumented and resuscitated following randomization to epinephrine or vasopressin through a low umbilical venous catheter. Results: Eight lambs achieved ROSC prior to medication. Epinephrine achieved ROSC in 7/10 lambs by 8 ± 2 min. Vasopressin achieved ROSC in 3/9 lambs by 13 ± 6 min. Plasma vasopressin levels in nonresponders were much lower than responders after the first dose. Vasopressin caused in vivo increased pulmonary blood flow and in vitro coronary vasoconstriction. Conclusions: Vasopressin resulted in lower incidence and longer time to ROSC compared to epinephrine in a perinatal model of cardiac arrest supporting the current recommendations for exclusive use of epinephrine in neonatal resuscitation.

Inadequate Bioavailability of Intramuscular Epinephrine in a Neonatal Asphyxia Model

BACKGROUND

Over half a million newborn deaths are attributed to intrapartum related events annually, the majority of which occur in low resource settings. While progress has been made in reducing the burden of asphyxia, novel approaches may need to be considered to further decrease rates of newborn mortality. Administration of intravenous, intraosseous or endotracheal epinephrine is recommended by the Newborn Resuscitation Program (NRP) with sustained bradycardia at birth. However, delivery by these routes requires both advanced skills and specialized equipment. Intramuscular (IM) epinephrine may represent a simple, low cost and highly accessible alternative for consideration in the care of infants compromised at birth. At present, the bioavailability of IM epinephrine in asphyxia remains unclear.

METHODS

Four term fetal lambs were delivered by cesarean section and asphyxiated by umbilical cord occlusion with resuscitation after 5 min of asystole. IM epinephrine (0.1 mg/kg) was administered intradeltoid after 1 min of positive pressure ventilation with 30 s of chest compressions. Serial blood samples were obtained for determination of plasma epinephrine concentrations by ELISA.

RESULTS

Epinephrine concentrations failed to increase following administration via IM injection. Delayed absorption was observed after return of spontaneous circulation (ROSC) in half of the studies.

CONCLUSIONS

Inadequate absorption of epinephrine occurs with IM administration during asphyxial cardiac arrest, implying this route would be ineffective in infants who are severely compromised at birth. Late absorption following ROSC raises concerns for risks of side effects. However, the bioavailability and efficacy of intramuscular epinephrine in less profound asphyxia may warrant further evaluation.

Not Crying After Birth as a Predictor of Not Breathing

BACKGROUND

Worldwide, every year, 6 to 10 million infants require resuscitation at birth according to estimates based on limited data regarding "nonbreathing" infants. In this article, we aim to describe the incidence of "noncrying" and nonbreathing infants after birth, the need for basic resuscitation with bag-and-mask ventilation, and death before discharge.

METHODS

We conducted an observational study of 19 977 infants in 4 hospitals in Nepal. We analyzed the incidence of noncrying or nonbreathing infants after birth. The sensitivity of noncrying infants with nonbreathing after birth was analyzed, and the risk of predischarge mortality between the 2 groups was calculated.

RESULTS

The incidence of noncrying infants immediately after birth was 11.1%, and the incidence of noncrying and nonbreathing infants was 5.2%. Noncrying after birth had 100% sensitivity for nonbreathing infants after birth. Among the "noncrying but breathing" infants, 9.5% of infants did not breathe at 1 minute and 2% did not to breathe at 5 minutes. Noncrying but breathing infants after birth had almost 12-fold odds of predischarge mortality (adjusted odds ratio 12.3; 95% confidence interval, 5.8-26.1).

CONCLUSIONS

All nonbreathing infants after birth do not cry at birth. A proportion of noncrying but breathing infants at birth are not breathing by 1 and 5 minutes and have a risk for predischarge mortality. With this study, we provide evidence of an association between noncrying and nonbreathing. This study revealed that noncrying but breathing infants require additional care. We suggest noncrying as a clinical sign for initiating resuscitation and a possible denominator for measuring coverage of resuscitation.

Volume Versus Mass Dosing of Epinephrine for Neonatal Resuscitation: A Randomized Trial

BACKGROUND

Intravenous epinephrine for neonatal resuscitation requires weight-based calculations. Epinephrine is available in 2 different concentrations, increasing the risk of dosing errors. Expert panels have conflicting recommendations for the ordering method. The Neonatal Resuscitation Program recommends the volume (milliliters per kilogram) method, whereas the Institute for Safe Medication Practices recommends the mass (milligrams per kilogram) method. In this study, we aim to determine if the mass method is more accurate and efficient than the volume method.

METHODS

In a randomized crossover simulation study, 70 NICU and pediatric emergency department nurses calculated the intended dose then prepared epinephrine using both the mass and volume methods. Both epinephrine concentrations were available. Scenarios were video recorded and timed. The primary outcome was the proportion of epinephrine doses prepared correctly. Variables associated with correct dosing were analyzed by using logistic regression.

RESULTS

Of 136 total doses, 77 (57%) were prepared correctly. The correct intended dose was calculated more frequently by using the mass method (82% vs 68%; risk difference 15%; 95% confidence interval 3% to 26%), but there was no difference in the proportion of doses that were actually prepared correctly (53% of mass method doses versus 60% of volume method doses; risk difference -7%; 95% confidence interval -24% to 9%). There was no difference between methods in the time required to prepare the dose. Selecting the correct epinephrine concentration was the only variable associated with correct dosing.

CONCLUSIONS

The mass method was neither more accurate nor more efficient. Nurses made frequent errors when using both methods. This is a serious patient safety risk. Additional educational and medication safety interventions are urgently needed.

Epinephrine in Neonatal Resuscitation

Epinephrine is the only medication recommended by the International Liaison Committee on Resuscitation for use in newborn resuscitation. Strong evidence from large clinical trials is lacking owing to the infrequent use of epinephrine during neonatal resuscitation. Current recommendations are weak as they are extrapolated from animal models or pediatric and adult studies that do not adequately depict the transitioning circulation and fluid-filled lungs of the newborn in the delivery room. Many gaps in knowledge including the optimal dosing, best route and timing of epinephrine administration warrant further studies. Experiments on a well-established ovine model of perinatal asphyxial cardiac arrest closely mimicking the newborn infant provide important information that can guide future clinical trials.

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.

Current Challenges in Neonatal Resuscitation: What is the Role of Adrenaline?

Adrenaline, also known as epinephrine, is a hormone, neurotransmitter, and medication. It is the best established drug in neonatal resuscitation, but only weak evidence supports current recommendations for its use. Furthermore, the available evidence is partly based on extrapolations from adult studies, and this introduces further uncertainty, especially when considering the unique physiological characteristics of newly born infants. The timing, dose, and route of administration of adrenaline are still debated, even though this medication has been used in neonatal resuscitation for a long time. According to the most recent Neonatal Resuscitation Guidelines from the American Heart Association, adrenaline use is indicated when the heart rate remains < 60 beats per minute despite the establishment of adequate ventilation with 100% oxygen and chest compressions. The aforementioned guidelines recommend intravenous administration (via an umbilical venous catheter) of adrenaline at a dose of 0.01-0.03 mg/kg (1:10,000 concentration). Endotracheal administration of a higher dose (0.05-0.1 mg/kg) may be considered while venous access is being obtained, even if supportive data for endotracheal adrenaline are lacking. The safety and efficacy of intraosseous administration of adrenaline remain to be investigated. This article reviews the evidence on the circulatory effects and tolerability of adrenaline in the newborn, discusses literature data on adrenaline use in neonatal cardiopulmonary resuscitation, and describes international recommendations and outcome data regarding the use of this medication during neonatal resuscitation.

Epinephrine Use during Newborn Resuscitation

Epinephrine use in the delivery room for resuscitation of the newborn is associated with significant morbidity and mortality. Evidence for optimal dose, timing, and route of administration of epinephrine during neonatal resuscitation comes largely from extrapolated adult or animal literature. In this review, we provide the current recommendations for use of epinephrine during neonatal resuscitation and also the evidence behind these recommendations. In addition, we review the current proposed mechanism of action of epinephrine during neonatal resuscitation, review its adverse effects, and identify gaps in knowledge requiring urgent research.

Optimal Chest Compression Rate and Compression to Ventilation Ratio in Delivery Room Resuscitation: Evidence from Newborn Piglets and Neonatal Manikins

Cardiopulmonary resuscitation (CPR) duration until return of spontaneous circulation (ROSC) influences survival and neurologic outcomes after delivery room (DR) CPR. High quality chest compressions (CC) improve cerebral and myocardial perfusion. Improved myocardial perfusion increases the likelihood of a faster ROSC. Thus, optimizing CC quality may improve outcomes both by preserving cerebral blood flow during CPR and by reducing the recovery time. CC quality is determined by rate, CC to ventilation (C:V) ratio, and applied force, which are influenced by the CC provider. Thus, provider performance should be taken into account. Neonatal resuscitation guidelines recommend a 3:1 C:V ratio. CCs should be delivered at a rate of 90/min synchronized with ventilations at a rate of 30/min to achieve a total of 120 events/min. Despite a lack of scientific evidence supporting this, the investigation of alternative CC interventions in human neonates is ethically challenging. Also, the infrequent occurrence of extensive CPR measures in the DR make randomized controlled trials difficult to perform. Thus, many biomechanical aspects of CC have been investigated in animal and manikin models. Despite mathematical and physiological rationales that higher rates and uninterrupted CC improve CPR hemodynamics, studies indicate that provider fatigue is more pronounced when CC are performed continuously compared to when a pause is inserted after every third CC as currently recommended. A higher rate (e.g., 120/min) is also more fatiguing, which affects CC quality. In post-transitional piglets with asphyxia-induced cardiac arrest, there was no benefit of performing continuous CC at a rate of 90/min. Not only rate but duty cycle, i.e., the duration of CC/total cycle time, is a known determinant of CC effectiveness. However, duty cycle cannot be controlled with manual CC. Mechanical/automated CC in neonatal CPR has not been explored, and feedback systems are under-investigated in this population. Evidence indicates that providers perform CC at rates both higher and lower than recommended. Video recording of DR CRP has been increasingly applied and observational studies of what is actually done in relation to outcomes could be useful. Different CC rates and ratios should also be investigated under controlled experimental conditions in animals during perinatal transition.

Neonatal resuscitation: evolving strategies

Birth asphyxia accounts for about 23% of the approximately 4 million neonatal deaths each year worldwide (Black et al., Lancet, 2010, 375(9730):1969-87). The majority of newborn infants require little assistance to undergo physiologic transition at birth and adapt to extrauterine life. Approximately 10% of infants require some assistance to establish regular respirations at birth. Less than 1% need extensive resuscitative measures such as chest compressions and approximately 0.06% require epinephrine (Wyllie et al. Resuscitation, 2010, 81 Suppl 1:e260–e287). Transition at birth is mediated by significant changes in circulatory and respiratory physiology. Ongoing research in the field of neonatal resuscitation has expanded our understanding of neonatal physiology enabling the implementation of improved recommendations and guidelines on how to best approach newborns in need for intervention at birth. Many of these recommendations are extrapolated from animal models and clinical trials in adults. There are many outstanding controversial issues in neonatal resuscitation that need to be addressed. This article provides a comprehensive and critical literature review on the most relevant and current research pertaining to evolving new strategies in neonatal resuscitation. The key elements to a successful neonatal resuscitation include ventilation of the lungs while minimizing injury, the judicious use of oxygen to improve pulmonary blood flow, circulatory support with chest compressions, and vasopressors and volume that would hasten return of spontaneous circulation. Several exciting new avenues in neonatal resuscitation such as delayed cord clamping, sustained inflation breaths, and alternate vasopressor agents are briefly discussed. Finally, efforts to improve resuscitative efforts in developing countries through education of basic steps of neonatal resuscitation are likely to decrease birth asphyxia and neonatal mortality.

Drugs during delivery room resuscitation--what, when and why?

Although seldom needed, the short list of medications used for delivery room resuscitation of the newborn includes epinephrine and volume expanders. Naloxone, sodium bicarbonate and the use of other vasopressors are no longer considered helpful during acute resuscitation and are more often administered in the post-resuscitative period under special circumstances. This review examines the existing literature for the two commonly used medications in neonatal resuscitation and identifies the many knowledge gaps requiring further research.

The role of resuscitation drugs and placental transfusion in the delivery room management of newborn infants

Medications are used rarely in newborn resuscitations and are probably justifiable in less than 0.1% of births. Doses used are mainly extrapolated from animal and adult data. Despite this, the drugs used, their order and route of administration have all been sources of controversy for many years. There have been polarised views, often focusing upon adrenaline and sodium bicarbonate and more recently new drugs such as vasopressin have been suggested, once again extrapolating from adult experience. This article examines the sparse data behind the use of any medication at birth and the poor outcome data available. The appropriate decline in the indiscriminate use of volume expansion is considered and balanced by the increasing evidence in favour of delayed clamping of the umbilical cord. Focusing on the basic steps of resuscitation, improving the quality of their application and avoiding relative hypovolaemia, must improve the quality of outcome data. The place of medications in newborn resuscitation should be regarded as experimental and still requires evidence to justify their use especially in premature babies.

Moving from experience to evidence: changes in US Neonatal Resuscitation Program based on International Liaison Committee on Resuscitation Review

The Neonatal Workgroup of the International Liaison Committee on Resuscitation recently made available their rigorous review of the scientific evidence base for selected neonatal resuscitation issues. The Neonatal Resuscitation Program guidelines have been recently revised based on that review and published as the Textbook of Neonatal Resuscitation, 5th edn. This review article highlights pertinent changes in recommendations, including revisions in: oxygen use; CO(2) detectors for confirmation of intubation; management of the infant born through meconium-stained amniotic fluid; initial ventilation devices and strategies; thermal protection of very small preterm infants; medications, including doses and routes of delivery; postresuscitation therapies for consideration and ethical issues in initiation and discontinuation of resuscitation. Journal of Perinatology (2008) 28, S35-S40; doi:10.1038/jp.2008.48.

Neonatal resuscitation--an analysis of the transatlantic divide

AIM

To highlight the main differences between the current editions of the Newborn Life Support (NLS; Resuscitation Council, UK) and the Neonatal Resuscitation Program (NRP; American Academy of Pediatrics and American Heart Association), and to analyse differences between the evidence underlying NLS and NRP.

MATERIAL AND METHODS

We undertook a detailed comparison of recommendations and references, based on the NLS and the NRP provider course manuals issued in 2006. Literature on neonatal resuscitation, published in 2005 and thereafter, was searched, focusing on controversies between NLS and NRP.

RESULTS

A multitude of important differences between NLS and NRP have been reaffirmed in their current editions, leading to conflicting messages regarding many aspects of resuscitation. An incongruent selection of evidence appears to be a major factor accounting for this divergence.

CONCLUSION

To avoid confusion among health care providers and to support the credibility of both NLS and NRP, an intensified dialogue and a more congruent evidence base between NRP and NLS is required. Mutual recognition of equivalency appears unrealistic until substantial progress in this direction has been achieved.