Evaluation of the Neonatal Resuscitation Program's recommended chest compression depth using computerized tomography imaging

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.

Using computed tomography to evaluate proper chest compression depth for cardiopulmonary resuscitation in Thai population: A retrospective cross-sectional study

INTRODUCTION

The effectiveness of cardiopulmonary resuscitation is determined by appropriate chest compression depth and rate. The American Heart Association recommended CC depth at 5-6 cm to indicate proper cardiac output during cardiac arrest. However, many studies showed the differences in the body builds between Caucasians and Asians. Therefore, this study aimed to determine heart compression fraction (HCF) in the Thai population by using contrast-enhanced computed tomography (CT) scan of the chest and a mathematical model.

MATERIALS AND METHODS

Consecutive contrast-enhanced CT scans of the chest performed at Ramathibodi Hospital were retrospectively reviewed from January to March 2018 by two independent radiologists. Patients' characteristics, including gender, age, weight, height, and pre-existing diseases, were recorded, and the chest parameters were measured from a CT scan. The heart compression fraction (HCF) was subsequently calculated.

RESULTS

Of 306 subjects, there were 139 (45.4%) males, 148 (47.4%) lung diseases and 10 (3.3%) heart diseases. Mean age and BMI were 60.4 years old and 23.8 kg/m2, respectively. Chest diameter, heart diameter, and non-cardiac soft tissue were significantly smaller in females compared to males. Mean (SD) HCF proportional with 50 mm and 60 mm depth were 38.3% (13.3%) and 50% (14.3%), respectively. There were significant differences of HCF proportional by 50 mm and 60 mm depth between men and women (33.2% vs 42.6% and 44% vs 54.9%, respectively (P<0.001)). In addition, a decrease in HCF was significantly observed among higher BMI groups.

CONCLUSION

The CT scan and mathematical model showed that 38% and 50% HCF proportions were generated by 50 mm and 60 mm CC depth. HCF proportions were significantly different between genders and among BMI groups. The recommended depth of 5-6 cm is likely to provide sufficient CC depth in the population of Thailand.

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.

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.

Effects of varying chest compression depths on carotid blood flow and blood pressure in asphyxiated piglets

BACKGROUND

Current neonatal resuscitation guidelines recommend chest compressions (CCs) should be delivered to a depth of approximately 1/3 of the anterior-posterior (AP) chest diameter. The aim of the study was to investigate the haemodynamic effects of different CC depths in a neonatal piglet model.

METHODS

CCs were performed with an automated CC machine with 33%, 40% and 25% AP chest diameter in all piglets in the same order for a duration of 3 min each.

RESULTS

Eight newborn piglets (age 1-3 days, weight 1.7-2.3 kg) were included in the study. Carotid blood flow (CBF) and systolic blood pressure were the highest using a CC depth of 40% AP chest diameter (19.3±7.5 mL/min/kg and 58±32 mm Hg).

CONCLUSION

CC depth influences haemodynamic parameters in asphyxiated newborn piglets during cardiopulmonary resuscitation. The highest CBF and systolic blood pressure were achieved using a CC depth of 40% AP chest diameter.

TRIAL REGISTRATION NUMBER

PCTE0000148.

Evaluation of the proper chest compression depth for neonatal resuscitation using computed tomography: A retrospective study

This study was created to assess whether a 30-mm depth of chest compression (CC) is sufficient and safe for neonatal cardiopulmonary resuscitation.This retrospective analysis was performed with chest computed tomography scans of neonates in 2 hospitals between 2004 and 2018. We measured several chest parameters and calculated heart compression fraction (HCF) using the ejection fraction formula. We evaluated whether one-third of the external anterior-posterior (AP) diameter and HCF with them are the equivalent to 25-, 30-, 35 mm and HCF with them, respectively, and the number of individuals with over-compression (internal chest AP diameter - compressed depth <10 mm) to estimate a safe CC depth. We divided the patients into term and preterm groups and compared their outcomes.In total, 63 of the 75 included individuals were analyzed, and one-third of the external lengths was equivalent to 30 ± 3 mm (P < .001). When the patients were divided into term (n = 53) and preterm (n = 10) groups, the equivalent depth was 30 ± 3 mm in the term group (P < .001) and 25 ± 2.5 mm in the preterm group (P = .004). The HCF with 30 mm was equivalent to that for one-third of the external length (P < .001). When we simulated CCs with a 30-mm depth, over-compression occurred more frequently in the preterm group (20%) compared to the term group (1.9%) (P = .014).A 30-mm depth could be appropriate for sufficient and safe neonatal resuscitation. Shallower CC should be considered in preterm babies.

What is the potential for over-compression using current paediatric chest compression guidelines? - A chest computed tomography study

Aim

We explored the potential for over-compression from current paediatric chest compression depth guidelines using chest computed tomography(CT) images of a large, heterogenous, Asian population.

Methods

A retrospective review of consecutive children, less than 18-years old, with chest CT images performed between from 2005 to 2017 was done. Demographic data were extracted from the electronic medical records. Measurements for internal and external anterior-posterior diameters (APD) were taken at lower half of the sternum. Simulated chest compressions were performed to evaluate the proportion of the population with residual internal cavity dimensions less than 0 mm (RICD < 0 mm, representing definite over-compression; with chest compression depth exceeding internal APD), and RICD less than 10 mm (RICD < 10 mm, representing potential over-compression).

Results

592 paediatric chest CT studies were included for the study. Simulated chest compressions of one-third external APD had the least potential for over-compression; no infants and 0.3% children had potential over-compression (RICD < 10 mm). 4 cm simulated chest compressions led to 18% (95% CI 13%-24%) of infants with potential over-compression, and this increased to 34% (95% CI 27%-41%) at 4.4 cm (upper limit of "approximately" 4 cm; 4 cm + 10%). 5 cm simulated compressions resulted in 8% (95% CI 4%-12%) of children 1 to 8-years-old with potential over-compression, and this increased to 22% (95% CI 16%-28%) at 5.5 cm (upper limit of "approximately" 5 cm, 5 cm + 10%).

Conclusion

In settings whereby chest compression depths can be accurately measured, compressions at the current recommended chest compression of approximately 4 cm (in infants) and 5 cm (in young children) could result in potential for over-compression.

European Resuscitation Council Guidelines 2021: Newborn resuscitation and support of transition of infants at birth

The European Resuscitation Council has produced these newborn life support guidelines, which are based on the International Liaison Committee on Resuscitation (ILCOR) 2020 Consensus on Science and Treatment Recommendations (CoSTR) for Neonatal Life Support. The guidelines cover the management of the term and preterm infant. The topics covered include an algorithm to aid a logical approach to resuscitation of the newborn, factors before delivery, training and education, thermal control, management of the umbilical cord after birth, initial assessment and categorisation of the newborn infant, airway and breathing and circulation support, communication with parents, considerations when withholding and discontinuing support.

[Newborn resuscitation and support of transition of infants at birth]

The European Resuscitation Council has produced these newborn life support guidelines, which are based on the International Liaison Committee on Resuscitation (ILCOR) 2020 Consensus on Science and Treatment Recommendations (CoSTR) for Neonatal Life Support. The guidelines cover the management of the term and preterm infant. The topics covered include an algorithm to aid a logical approach to resuscitation of the newborn, factors before delivery, training and education, thermal control, management of the umbilical cord after birth, initial assessment and categorisation of the newborn infant, airway and breathing and circulation support, communication with parents, considerations when withholding and discontinuing support.

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.

Retrospective Study Using Computed Tomography to Compare Sufficient Chest Compression Depth for Cardiopulmonary Resuscitation in Obese Patients

Background This study aimed to investigate the relationship between body mass index (BMI) and sufficient chest compression depth (CCD) in obese patients by a mathematical model. Methods and Results This retrospective analysis was performed with chest computed tomography images conducted between 2006 and 2018. We classified the selected individuals into underweight (<18.5), normal weight (≥18.5, <25), overweight (≥25, <30), and obese (≥30) groups according to BMI (kg/m2). We defined heart compression fraction (HCF) as [Formula: see text] and estimated under-HCF (the value of HCF <20%), and over-HCF (the residual depth <2 cm after simulation with chest compression depth 5 and 6 cm). We compared these outcomes between BMI groups. Of 30 342 individuals, 8856 were selected and classified into 4 BMI groups from a database. We randomly selected 100 individuals in each group and analyzed a total of 400 individuals' cases. Higher BMI groups had a significantly decreased HCF with both 5 and 6 cm depth (P<0.001). The proportion of under-HCF with both depths increased according to BMI group, whereas the proportion of over-HCF decreased except for the 5 cm depth (P<0.001). The adjusted odds ratio of under-HCF, according to BMI group after adjustment of age and sex, was 7.325 (95% CI, 3.412-15.726; P<0.001), with 5 cm and 10.517 (95% CI, 2.353-47.001; P=0.002) with 6 cm depth, respectively. Conclusions The recommended chest compression depth of 5 to 6 cm in the current international guideline is unlikely to provide sufficient ejection fraction during cardiopulmonary resuscitation in obese patients.

Can real-time feedback improve the simulated infant cardiopulmonary resuscitation performance of basic life support and lay rescuers?

BACKGROUND

Performing high-quality chest compressions during cardiopulmonary resuscitation (CPR) requires achieving of a target depth, release force, rate and duty cycle.

OBJECTIVE

This study evaluates whether 'real time' feedback could improve infant CPR performance in basic life support-trained (BLS) and lay rescuers. It also investigates whether delivering rescue breaths hinders performing high-quality chest compressions. Also, this study reports raw data from the two methods used to calculate duty cycle performance.

METHODOLOGY

BLS (n=28) and lay (n=38) rescuers were randomly allocated to respective 'feedback' or 'no-feedback' groups, to perform two-thumb chest compressions on an instrumented infant manikin. Chest compression performance was then investigated across three compression algorithms (compression only; five rescue breaths then compression only; five rescue breaths then 15:2 compressions). Two different routes to calculate duty cycle were also investigated, due to conflicting instruction in the literature.

RESULTS

No-feedback BLS and lay groups demonstrated <3% compliance against each performance target. The feedback rescuers produced 20-fold and 10-fold increases in BLS and lay cohorts, respectively, achieving all targets concurrently in >60% and >25% of all chest compressions, across all three algorithms. Performing rescue breaths did not impede chest compression quality.

CONCLUSIONS

A feedback system has great potential to improve infant CPR performance, especially in cohorts that have an underlying understanding of the technique. The addition of rescue breaths-a potential distraction-did not negatively influence chest compression quality. Duty cycle performance depended on the calculation method, meaning there is an urgent requirement to agree a single measure.

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.

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 Heart Proportions Compressed by Chest Compressions Between Geriatric and Nongeriatric Patients Using Mathematical Methods and Chest Computed Tomography: A Retrospective Study

Background

Current guidelines recommended that chest compression depths during car-diopulmonary resuscitation (CPR) should be at least one-fifth of the external chest ante-riorposterior (AP) diameter. The chest AP diameter increases because of dorsal kyphosis, senile emphysema, and poor lung compliance associated with aging. This study aimed to compare the proportion of the heart compressed by chest compression (based on the ejection fraction [EF]) in geriatric and nongeriatric patients.

Methods

We performed a retrospective analysis of the chest computed tomography findings obtained between January 2010 and August 2016 and measured the chest anatomical parameters such as the perpendicular external and internal chest AP diameters with the heart AP diameter. Based on values of these parameters, EFs with 50- and 60-mm depths were obtained. In addition, we investigated and compared the proportion of 50- and 60-mm depths and heart AP to external chest AP diameter between the 2 groups.

Results

We randomly selected and analyzed 100 of 1,921 geriatric and 100 of 22,090 nongeriatric populations from a database. The means±standard deviations of EFs with 50- and 60-mm depths for geriatric and nongeriatric people were 37.1%±12.1% vs. 43.2%±13.8% and 47.5%±12.8% vs. 54.6%±14.8%, respectively (all p<0.001). The proportion of 50- and 60-mm depths and heart AP to external chest AP diameter were significantly different between the 2 groups (all p<0.05).

Conclusion

Chest compression depths based on current guidelines are not sufficient for geriatric patients during CPR; hence, deeper chest compressions would be considered.

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.

Verification of the Optimal Chest Compression Depth for Children in the 2015 American Heart Association Guidelines: Computed Tomography Study

OBJECTIVE

The 2015 American Heart Association guidelines recommended pediatric rescue chest compressions of at least one-third the anteroposterior diameter of the chest, which equates to approximately 5 cm. This study evaluated the appropriateness of these two types by comparing their safeties in chest compression depth simulated by CT.

DESIGN

Retrospective study with data analysis conducted from January 2005 to June 2015 SETTING:: Regional emergency center in South Korea.

PATIENTS

Three hundred forty-nine pediatric patients 1-9 years old who had a chest CT scan.

INTERVENTIONS

Simulation of chest compression depths by CT.

MEASUREMENTS AND MAIN RESULTS

Internal and external anteroposterior diameter of the chest and residual internal anteroposterior diameter after simulation were measured from CT scans. The safe cutoff levels were differently applied according to age. One-third external anteroposterior diameters were compared with an upper limit of chest compression depth recommended for adults. Primary outcomes were the rates of overcompression to evaluate safety. Overcompression was defined as a negative value of residual internal anteroposterior diameter-age-specific cutoff level. Using a compression of 5-cm depth simulated by chest CT, 16% of all children (55/349) were affected by overcompression. Those 1-3 years old were affected more than those 4-9 years old (p < 0.001). Upon one-third compression of chest anteroposterior depth, only one subject (0.3%) was affected by overcompression. Rate of one-third external anteroposterior diameter greater than 6 cm in children 8 and 9 years old was 16.1% and 33.3%, respectively.

CONCLUSIONS

A chest compression depth of one-third anteroposterior might be more appropriate than the 5-cm depth chest compression for younger Korean children. But, one-third anteroposterior depth chest compression might induce deep compressions greater than an upper limit of compression depth for adults in older Korean children.

Resuscitators who compared four simulated infant cardiopulmonary resuscitation methods favoured the three-to-one compression-to-ventilation ratio

AIM

Suboptimal cardiopulmonary resuscitation (CPR) is associated with a poor outcome, and international guidelines state that resuscitators should optimise compression and ventilation techniques with as few interruptions as possible. We investigated compression and ventilation quality during simulated CPR with four compression-to-ventilation (C:V) methods.

METHODS

In this crossover manikin study, 42 pairs of doctors, nurses, midwives and sixth-year medical students from two Norwegian hospitals provided two-minute resuscitation using the 3:1, 9:3 and 15:2 C:V methods and continuous chest compressions at 120 per minute with asynchronous ventilations (CCaV-120). We measured chest compression, ventilation mechanics and the resuscitators' preferences.

RESULTS

C:V methods 3:1 and 9:3 provided comparable chest compressions and ventilation mechanics, whereas 15:2 produced fewer ventilations and lower minute volumes. The CCaV-120 method was significantly less effective than the 3:1 C:V ratio method: the chest compression depth was 1.9 mm lower, there were 25 fewer chest compressions and 21 fewer ventilations per minute, and the minute volume was 69 mL lower. The 3:1 C:V method also provided better coordination between resuscitators.

CONCLUSION

Our comparison of four simulated infant cardiopulmonary resuscitation methods favoured the 3:1 C:V method, and the multidisciplinary group of participants felt it offered the best level of coordination between resuscitators.

Optimizing Prone Cardiopulmonary Resuscitation: Identifying the Vertebral Level Correlating With the Largest Left Ventricle Cross-Sectional Area via Computed Tomography Scan

BACKGROUND

Placing the patient in the prone position frequently is required for some surgical procedures. If cardiac arrest occurs and the patient cannot be safely turned supine, cardiopulmonary resuscitation (CPR) may need to be performed with the patient in the prone position. Although clear landmarks have been defined for supine CPR, the optimal hand position for CPR in the prone position has not been clearly determined. The purpose of this study was to determine anatomically the optimal hand position for CPR in the prone position.

METHODS

We reviewed retrospectively the chest computed tomography images of 100 patients taken in the prone position. The vertebral body levels crossing the medial angle of the scapula, the inferior angle of the scapula, and the spinous process of the vertebral body connected to the most inferior rib were identified, and we selected the image level at which the left ventricular (LV) cross-sectional area was the largest. This level was defined as the optimal compression level and correlated to surface anatomical landmarks. We calculated the ratio of the distance from the C7 spinous process to the level of the largest LV cross-sectional area divided by the distance from the C7 spinous process to the spinous process of the vertebral body connected with the most inferior rib.

RESULTS

The level of the largest LV cross-sectional area in the prone position was 1 vertebral segment below the inferior angle of the scapula in 45% (99% confidence interval [CI], 33-58) of patients and 0 to 2 vertebral segments below that in 95% (99% CI, 86-98) of patients. The mean (SD) ratio of the distance from the C7 spinous process to the level of the largest LV cross-sectional area divided by the distance from the C7 spinous process to T12 spinous process was 67% ± 7% (99% CI, 65-69).

CONCLUSIONS

When the patient is positioned prone, the largest LV cross-sectional area is 0 to 2 vertebral segments below the inferior angle of the scapula in at least 86% of patients. Further studies are needed to determine whether this position is optimal for chest compressions in the prone position.

Are the current guideline recommendations for neonatal cardiopulmonary resuscitation safe and effective?

A recently published review of approaches to optimize chest compressions in the resuscitation of asphyxiated newborns discussed the current recommendations and explored potential determinants of effective neonatal cardiopulmonary resuscitation (CPR). However, not all potential determinants of effective neonatal CPR were explored. Chest compression shallower than the current guideline recommendation of approximately 33% of the anterior-posterior (AP) chest diameter may be safer and more effective. From a physiological standpoint, high-velocity brief duration shallower compression may be more effective than current recommendations. The application of a 1- or 2-finger method of high-impulse CPR, which would depend on the size of the subject, may be more effective than using a 2-thumb (TT) encircling hands method of CPR. Adrenaline should not be used in the treatment of asphyxiated neonates and when necessary titrated vasopressin should be used.

A review of approaches to optimise chest compressions in the resuscitation of asphyxiated newborns

OBJECTIVE

Provision of chest compressions (CCs) and/or medications in the delivery room is associated with poor outcomes. Based on the physiology of perinatal asphyxia, we aimed to provide an overview of current recommendations and explore potential determinants of effective neonatal cardiopulmonary resuscitation (CPR): balancing ventilations and CC, CC rate, depth, full chest recoil, CC technique and adrenaline.

DESIGN

A search in the databases MEDLINE (Ovid) and EMBASE until 10 April 2015.

SETTING

Delivery room.

PATIENTS

Asphyxiated newborn infants.

INTERVENTIONS

CCs.

MAIN OUTCOME MEASURES

Haemodynamics, recovery and survival.

RESULTS

Current evidence is derived from mathematical models, manikin and animal studies, and small case series. No randomised clinical trials examining neonatal CC have been performed. There is no evidence to refute a CC to ventilation (C:V) ratio of 3:1. Raising the intrathoracic pressure, for example, by superimposing a sustained inflation on uninterrupted CC, and a CC rate >120/min may be beneficial. The optimal neonatal CC depth is unknown, but factors influencing depth and consistency include the C:V ratio. Incomplete chest wall recoil can cause less negative intrathoracic pressure between CC and reduced CPR effectiveness. CC should be performed with the two-thumb method over the lower third of the sternum. The optimal dose, route and timing of adrenaline administration remain to be determined.

CONCLUSIONS

Successful CPR requires the delivery of high-quality CC, encompassing optimal (A) C:V ratio (B) rate, (C) depth, (D) chest recoil between CC, (E) technique and (F) adrenaline dosage. More animal studies with high translational value and randomised clinical trials are needed.

Proper compression landmark and depth for cardiopulmonary resuscitation in patients with pectus excavatum: a study using CT

OBJECTIVE

To determine by chest CT the proper compression landmark and depth for cardiopulmonary resuscitation in patients with pectus excavatum (PE).

METHODS

The chest CT of 22 patients with PE (mean age=27 years; range 16-53 years, 10 male) from March 2002 to September 2011 were retrospectively evaluated as follows: length of sternum, external thickness/internal thickness (ET/IT) of the chest and the intrathoracic structures in the level of lower half (LH) of the sternum. In addition, Haller index (HI) and the degree of leftward displacement of the heart were measured. Finally, variables were also measured in an age/sex-matched control group (n=22) with no evidence of any chest wall deformity.

RESULTS

The sternal length was not different and LH of the sternum was adequate to compress left ventricle (LV) in both groups. Patients had a significant higher HI and showed a greater leftward displacement of LV centre with a mean difference of 11 mm. PE patients showed a lesser ET/IT with a mean difference of approximately 20 mm than controls (mean ET/IT=174±18/70±10 mm vs 199±23/93±15 mm, p<0.001).

CONCLUSIONS

The LH of the sternum is an appropriate chest compression landmark in PE patients to compress LV, although the centre of LV shows slightly leftward displacement. Since PE patients have sunken chest, a 3-4 cm may be the proper compression depth in the patients when considering the current compression guideline in normal subjects is 5-6 cm.

Factors modulating effective chest compressions in the neonatal period

The need for chest compressions in the newborn is a rare occurrence. The methods employed for delivery of chest compressions have been poorly researched. Techniques that have been studied include compression:ventilation ratios, thumb versus finger method of delivering compressions, depth of compression, site on chest of compression, synchrony or asynchrony of breaths with compressions, and modalities to improve the compression technique and consistency. Although still in its early days, an evidence-based guideline for chest compressions is beginning to take shape.

Chest compressions for bradycardia or asystole in neonates

When effective ventilation fails to establish a heart rate of greater than 60 bpm, cardiac compressions should be initiated to improve perfusion. The 2-thumb method is the most effective and least fatiguing technique. A ratio of 3 compressions to 1 breath is recommended to provide adequate ventilation, the most common cause of newborn cardiovascular collapse. Interruptions in compressions should be limited to not diminishing the perfusion generated. Oxygen (100%) is recommended during compressions and can be reduced once adequate heart rate and oxygen saturation are achieved. Limited clinical data are available to form newborn cardiac compression recommendations.

Does a more "physiological" infant manikin design effect chest compression quality and create a potential for thoracic over-compression during simulated infant CPR?

Poor survivability following infant cardiac arrest has been attributed to poor quality chest compressions. Current infant CPR manikins, used to teach and revise chest compression technique, appear to limit maximum compression depths (CDmax) to 40 mm. This study evaluates the effect of a more "physiological" CDmax on chest compression quality and assesses whether proposed injury risk thresholds are exceeded by thoracic over-compression. A commercially available infant CPR manikin was instrumented to record chest compressions and modified to enable compression depths of 40 mm (original; CDmax40) and 56 mm (the internal thoracic depth of a three-month-old male infant; CDmax56). Forty certified European Paediatric Life Support instructors performed two-thumb (TT) and two-finger (TF) chest compressions at both CDmax settings in a randomised crossover sequence. Chest compression performance was compared to recommended targets and compression depths were compared to a proposed thoracic over-compression threshold. Compressions achieved greater depths across both techniques using the CDmax56, with 44% of TT and 34% of TF chest compressions achieving the recommended targets. Compressions achieved depths that exceeded the proposed intra-thoracic injury threshold. The modified manikin (CDmax56) improved duty cycle compliance; however, the chest compression rate was consistently too high. Overall, the quality of chest compressions remained poor in comparison with internationally recommended guidelines. This data indicates that the use of a modified manikin (CDmax56) as a training aid may encourage resuscitators to habitually perform deeper chest compressions, whilst avoiding thoracic over-compression and thereby improving current CPR quality. Future work will evaluate resuscitator performance within a more realistic, simulated CPR environment.

Increased incidence of CPR-related rib fractures in infants--is it related to changes in CPR technique?

OBJECTIVE

A recent increase in the number of infants presenting at autopsy with rib fractures associated with cardio-pulmonary resuscitation (CPR) precipitated a study to determine whether such a phenomenon was related to recent revision of paediatric resuscitation guidelines.

METHODS

We conducted a review of autopsy reports from 1997 to 2008 on 571 infants who had CPR performed prior to death.

RESULTS

Analysis of the study population revealed CPR-related rib fractures in 19 infants (3.3%), 14 of whom died in the 2006-2008 period. The difference in annual frequency of CPR-related fractures between the periods before and after revision of paediatric CPR guidelines was statistically highly significant.

CONCLUSIONS

The findings indicate that CPR-associated rib fractures have become more frequent in infants since changes in CPR techniques were introduced in 2005. This has important implications for both clinicians and pathologists in their assessment of rib fractures in this patient population.

Part 10: Pediatric basic and advanced life support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

Note From the Writing Group: Throughout this article, the reader will notice combinations of superscripted letters and numbers (eg, “Family Presence During ResuscitationPeds-003”). These callouts are hyperlinked to evidence-based worksheets, which were used in the development of this article. An appendix of worksheets, applicable to this article, is located at the end of the text. The worksheets are available in PDF format and are open access.