Poor Concordance of One‐Third Anterior–Posterior Chest Diameter Measurements With Absolute Age‐Specific Chest Compression Depth Targets in Pediatric Cardiac Arrest Patients

Abstract

Background

Current pediatric cardiac arrest guidelines recommend depressing the chest by one‐third anterior–posterior diameter (APD), which is presumed to equate to absolute age‐specific chest compression depth targets (4 cm for infants and 5 cm for children). However, no clinical studies during pediatric cardiac arrest have validated this presumption. We aimed to study the concordance of measured one‐third APD with absolute age‐specific chest compression depth targets in a cohort of pediatric patients with cardiac arrest.

Methods and Results

This was a retrospective observational study from a multicenter, pediatric resuscitation quality collaborative (pediRES‐Q [Pediatric Resuscitation Quality Collaborative]) from October 2015 to March 2022. In‐hospital patients with cardiac arrest ≤12 years old with APD measurements recorded were included for analysis. One hundred eighty‐two patients (118 infants >28 days old to <1 year old, and 64 children 1 to 12 years old) were analyzed. The mean one‐third APD of infants was 3.2 cm (SD, 0.7 cm), which was significantly smaller than the 4 cm target depth (P<0.001). Seventeen percent of the infants had one‐third APD measurements within the 4 cm ±10% target range. For children, the mean one‐third APD was 4.3 cm (SD, 1.1 cm). Thirty‐nine percent of children had one‐third APD within the 5 cm ±10% range. Except for children 8 to 12 years old and overweight children, the measured mean one‐third APD of the majority of the children was significantly smaller than the 5 cm depth target (P<0.05).

Conclusions

There was poor concordance between measured one‐third APD and absolute age‐specific chest compression depth targets, particularly for infants. Further study is needed to validate current pediatric chest compression depth targets and evaluate the optimal chest compression depth to improve cardiac arrest outcomes.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02708134.

Nonstandard Abbreviations and Acronyms

APD

anterior–posterior diameter

pediRES‐Q

Pediatric Resuscitation Quality Collaborative

Clinical Perspective.

What Is New?

• This is the first clinical study of a multiracial cohort of infants and children with cardiac arrest who had their anterior–posterior chest diameter measured as part of their data collection.

• The study found poor concordance between measured chest depth targets (one‐third anterior–posterior chest diameter) and absolute age‐specific chest compression depth targets of 4 cm in infants and 5 cm in children.

• The measured mean one‐third anterior–posterior chest diameters of infants, children <8 years old, and nonoverweight children were significantly smaller than their recommended absolute chest compression depth targets.

What Are the Clinical Implications?

• This study suggests that the current recommended one‐third anterior–posterior chest diameters and absolute age‐specific chest compression depth targets may not be similar, especially for infants <6 months old.

• Clinical trials are needed to validate our approach to current pediatric chest compression depth targets and to investigate the optimal chest compression depth targets associated with neurologically favorable survival in infants and children after cardiac arrest.

The 2020 International Liaison Committee on Resuscitation recommendations for pediatric chest compression depth targets suggest that rescuers should compress the chest of a pediatric patient in cardiac arrest by at least one‐third of the anterior–posterior diameter (APD), which is assumed to be similar to ≈1.5 inches (4 cm) for infants, and ≈2 inches (5 cm) in children. ¹ These recommendations were based on low‐quality evidence ² from radiologic ³ , ⁴ studies and observational studies with older technology using single‐sensor chest compression feedback devices. ⁵ , ⁶ Although many resuscitation councils follow these guideline recommendations on chest compression depth targets that allow for both relative and absolute compression depth targets, there were minor variations in their recommendation on both targets. ⁶ For example, some councils recommend a relative chest compression depth target of at least or approximately one‐third APD. ⁷ , ⁸ , ⁹

Both approaches to pediatric chest compression depth targets (compressing to one‐third APD and to the absolute age‐specific depth target of 4 or 5 cm) are generally accepted and presumed to be similar by clinicians. However, a recent pediatric chest computed tomography study ¹⁰ in a pediatric Asian cohort reported that the 2 chest compression depth targets had poor concordance, especially for infants and young children. However, this study did not include actual pediatric patients with cardiac arrest. If the 2 pediatric chest compression depth targets are significantly different in infants and children in cardiac arrest, there could be potential for over‐ or undercompression when one chest compression target depth is chosen over the other.

Our primary objective was to study the concordance of measured one‐third APD with absolute age‐specific chest compression depth targets in a multiracial cohort of infants and children who had experienced cardiac arrest. We also investigated the impact of epidemiological factors (age, sex, race), and body habitus (based on weight, length/height, age‐ and sex‐specific body mass index) on measured depth compression targets. We hypothesized that there would be relatively good concordance between the use of either approach to chest compression depth targets (one‐third APD and absolute age‐specific chest compression depth targets).

Methods

The data that support the findings of this study are available from the corresponding author (G.Y.O.) upon reasonable request. Data were collected from the pediRES‐Q (Pediatric Resuscitation Quality Collaborative) (ClinicalTrials.gov: NCT02708134). The pediRES‐Q Collaborative is a large, multicenter, international, pediatric resuscitation quality‐improvement network. The network consists of 60 participating sites in 17 countries across 5 continents (Asia, Australia, Europe, North and South America) (Data S1).

We analyzed prospectively collected epidemiologic (age, sex, race) and anthropometric data (weight, length/height, APD, and chest circumference) from children <18 years old who received chest compressions >1 minute duration and were entered into the pediRES‐Q database. ¹¹

Local institutional review boards or research ethics committees approved participation before enrolment in the collaborative and approved data use agreements per local institutional regulations. This study met the criteria for waiver of consent per the United States Code of Federal Regulations 45 CFR 46.116(d) and 45 CFR 46.408(a). Compliance with the Health Insurance Portability and Accountability Act (HIPAA) was maintained.

Patients' epidemiological and anthropometric data were entered into and managed using Research Electronic Data Capture tools coordinated and hosted at the Children's Hospital of Philadelphia under an agreement with the software's development consortium, led by Vanderbilt University. An additional data use agreement was obtained per local institutional regulations. Strict compliance with the Health Insurance Portability and Accountability Act to ensure patient confidentiality was maintained at all times.

Population

Index cardiac arrest events in infants (>28 days of life) and children ≤12 years old who had their chest dimensions entered into the database from October 2015 to March 2022 were included in the study. Premature infants and neonates (≤28 days of life) were excluded from this study. Adolescents >12 years were also excluded, because relative chest depth targets are not commonly used in this older age group who would have likely attained puberty. ⁸ , ¹²

Data Collection

Data on each resuscitation event were collected by a site investigator or research staff and entered into the pediRES‐Q database by research staff at each site trained and designated to perform data entry. The Data Coordinating Center completed a manual review and approval of each event record entered into the database.

Chest Measurements

Patient APD measurement was obtained at the conclusion of the resuscitation event while the patient was supine on the cardiopulmonary resuscitation (CPR) backboard. One end of a tape measure was placed on the surface immediately lateral to the subject's torso. The maximum height above the surface of the anterior aspect of the chest, halfway between the xyphoid and manubrium, was measured by a member of the site research team specifically trained and experienced in this procedure. ¹³ This process would be repeated up to 3 consecutive times to ensure accuracy.

To better characterize the acceptable range of age‐specific absolute chest compression depth targets, we a priori defined the term approximately to be within 10% variation of age‐specific absolute chest compression depth targets. ¹¹ For infants, ≈4 cm was defined as the range from 3.6 cm to 4.4 cm. For children, ≥1 year old, ≈5 cm was defined as the range from 4.5 cm to 5.5 cm.

Pediatric Body Habitus

Body habitus categories for the various age groups were defined as underweight, normal weight, and overweight based on age‐ and sex‐specific growth charts from the World Health Organization, Switzerland, and the US Centers for Disease Control and Prevention (Data S2).

Statistical Analysis

Demographic and clinical data were summarized by mean (SD), median (interquartile range), and number (percentage) where appropriate. One‐third APD was summarized by mean (SD) and compared between different body habitus categories by independent 2‐sample t test for infants and children, respectively. Mean one‐third APD of overall and each body habitus category was compared against the corresponding absolute chest compression depth targets (4 cm for infants and 5 cm for children) by 1‐sample t test. Concordance of one‐third APD with absolute chest compression depth targets was summarized by number (percentage) according to body habitus categories. The analyses were repeated for different age subgroups, sex, and races. Bee swarm plots were used to depict the relationship between one‐third APD and absolute chest compression depth targets. Association between patient characteristics, difference, and concordance of the 2 was assessed by linear regression and logistic regression, respectively. For continuous variables of body habitus centile and age, relationship with concordance and difference was assessed by fractional polynomial regression. Because we used the variable selection criterion of P<0.05, only univariable regression analyses were implemented. Statistical analyses were performed using Stata/SE 17.0 (StataCorp, College Station, TX). Bee swarm plots were produced by R 4.2.2 (R Foundation for Statistical Computing, Vienna, Austria). All statistical tests were 2‐sided with a 5% significance level.

Results

Data from 230 pediatric patients with cardiac arrest (October 2015 to March 2022) with APD measurements were included for analysis. Only the index event was included for the 17 patients who had >1 cardiac arrest event. Twenty‐one patients were excluded for missing essential data (ie, age, sex, and units of measurements). Ten patients who were >12 years old were excluded based on age exclusion criteria. Final analyses included 182 pediatric patients with complete data (Table 1).

Table 1.

Demographic and Clinical Characteristics of Patients

Patient characteristics	Infants (<1 y) (n=118)	Children (1–12 y) (n=64)
Age, y, median (IQR)	0.3 (0.1–0.5)	4.5 (1.9–6.8)
Sex, n (%)
Boy	74 (62.7)	33 (51.6)
Girl	44 (37.3)	31 (48.4)
Race, n (%)
White	69 (58.5)	27 (42.2)
Asian	13 (11.0)	19 (29.7)
Black	15 (12.7)	10 (15.6)
Other/unknown	21 (17.8)	8 (12.5)
Weight, kg, mean (SD)	5.00 (1.85)	17.16 (9.78)
Length/height, m, mean (SD)	0.56 (0.07)	0.99 (0.24)
Age‐ and sex‐specific body habitus,* n (%)
Normal weight	78 (66.1)	38 (59.4)
Underweight	18 (15.3)	12 (18.8)
Overweight	22 (18.6)	14 (21.9)
Anterior–posterior chest diameter, cm, mean (SD)	9.7 (2.1)	12.9 (3.2)

IQR indicates interquartile range.

^*Pediatric body habitus defined as <2 years, weight for length; and ≥2 years, body mass index.

The mean one‐third APD of all infants was 3.2 cm (SD, 0.7), and only 17% of infants' one‐third APD were within the 10% variation of the chest compression depth of 4 cm (ie, 3.6 cm to 4.4 cm). The vast majority of the infants' one‐third APD (78%) were <3.6 cm (lower limit of 10% variation of the 4‐cm chest compression depth target) (Table 2).

Table 2.

Concordance of One‐Third APD With Absolute Chest Compression Depth Targets by Age and Body Habitus Categories

Age group and body habitus	N (%)	One‐third external APD, cm			Difference between one‐third APD and absolute chest compression depth targets		Patients' one‐third APD measurement in relation to absolute chest compression depth targets
		Mean (SD)	Subgroup analysis on difference* between body habitus categories (95% CI)	P value	Difference† (95% CI)	P value	One‐third APD within ±10% of compression target‡, n (%)	One‐third APD <10% of compression target§, n (%)	One‐third APD >10% of compression target||, n (%)
Infants (<1 y) overall	118	3.2 (0.7)			−0.8 (−0.9 to −0.7)	<0.001¶	20 (17.0)	92 (78.0)	6 (5.1)
Normal weight	78 (66.1)	3.2 (0.7)	Reference	…	−0.8 (−0.9 to −0.6)	<0.001¶	14 (18.0)	61 (78.2)	3 (3.9)
Underweight	18 (15.3)	3.0 (0.6)	−0.3 (−0.6 to 0.1)	0.129	−1.0 (−1.3 to −0.8)	<0.001¶	3 (16.7)	15 (83.3)	0 (0.0)
Overweight	22 (18.6)	3.5 (0.8)	0.2 (−0.1 to 0.6)	0.151	−0.5 (−0.9 to −0.2)	0.003¶	3 (13.6)	16 (72.7)	3 (13.6)
Children (1–12 y) overall	64	4.3 (1.1)			−0.7 (−1.0 to −0.4)	<0.001¶	25 (39.1)	35 (54.7)	4 (6.3)
Normal weight	38 (59.4)	4.3 (1.0)	Reference	…	−0.7 (−1.1 to −0.4)	<0.001¶	14 (36.8)	22 (57.9)	2 (5.3)
Underweight	12 (18.8)	3.9 (0.8)	−0.4 (−1.0 to 0.2)	0.213	−1.1 (−1.6 to −0.6)	0.001¶	4 (33.3)	8 (66.7)	0 (0.0)
Overweight	14 (21.9)	4.8 (1.4)	0.5 (−0.2 to 1.2)	0.166	−0.3 (−1.0 to 0.5)	0.506	7 (50.0)	5 (35.7)	2 (14.3)

APD indicates anterior–posterior diameter.

^*Difference in mean one‐third APD between body habitus categories.

^† Mean one‐third APD minus absolute age‐specific chest compression depth targets (infants 4 cm, children 1 to 12 years old 5 cm).

^‡ Patients' one‐third APD within 10% of chest compression depth target of 4 cm (3.6–4.4 cm) in infants, and 5 cm (4.5–5.5 cm) in children according to body habitus categories.

^§ Patients' one‐third APD <3.6 cm in infants and <4.5 cm in children according to body habitus categories.

^|| Patients' one‐third APD >4.4 cm in infants and >5.5 cm in children according to body habitus categories.

^¶ Significant P values (<0.05).

The mean one‐third APD of the infants according to their body habitus categories is illustrated in Figure 1 (bee swarm plot).

Figure 1. Bee swarm plot of one‐third APD according to age and body habitus category.

APD indicates anterior–posterior diameter.

For children 1 to 12 years old, only 39.1% had one‐third APDs within the 10% variation of the chest compression depth of 5 cm (ie, 4.5–5.5 cm) (Table 2).

The one‐third APD measurements of the majority of the children (54.7%) were <4.5 cm. The mean one‐third APD of these children was 4.3 cm (SD, 1.1), significantly <5 cm (difference, −0.7 cm [95% CI, −1.0 to −0.4 cm]). Only the overweight children's one‐third APD of children were not significantly different from ≈5 cm (difference, −0.3 cm [95% CI, −1.0 to 0.5 cm]).

The relationships between the infants' and children's one‐third APD and their targeted chest compression depths, according to their age‐ and sex‐specific body habitus centiles, are reported in Table S1.

Fractional polynomial regressions scatter plots demonstrated linear associations between body habitus centiles in infants and children as continuous variables, and one‐third APDs are reported in Figures S1A and S1B, respectively. Fractional polynomial regression of concordance and difference between the 2 chest compression targets on body habitus centiles also suggested linear associations. For the infants, the associated odds ratio for concordance was 1.01 (95% CI, 0.99–1.02; P=0.227), and the associated coefficient for the difference between one‐third APD and their absolute chest compression depth target was 0.005 (95% CI, −0.002 to 0.008; P=0.002). For the children, the associated odds ratio for concordance was 1.00 (95% CI, 0.99–1.02; P=0.480), and the associated coefficient for the difference between one‐third APD and their absolute chest compression depth target as an outcome was 0.005 (95% CI, −0.002 to 0.012; P=0.167).

In our age subgroup analysis, infants ≥6 months old had significantly bigger mean one‐third APD than those <6 months old (3.6 cm versus 3.0 cm; difference, 0.5 cm [95% CI, 0.2–0.8 cm]). For infants <6 months old, the vast majority (87.2%) of their one‐third APD measurements were smaller than the ≈4 cm chest compression target (ie, 3.6 cm) (Table 3).

Table 3.

Concordance of One‐Third APD With Absolute Chest Compression Depth Targets by Age Subgroups

Age group	N (%)	One‐third external APD (cm)			Difference between one‐third APD and absolute chest compression depth targets		Patients' one‐third APD measurement in relation to absolute chest compression depth targets
		Mean (SD)	Subgroup analysis on difference* between age subgroups (95% CI)	P value	Difference† (95% CI)	P value	One‐third APD within ±10% of compression target‡, n (%)	One‐third APD <10% of compression target§, n (%)	One‐third APD >10% of compression target||, n (%)
Chest compression depth target of 4 cm ±10%
<6 mo	78 (66.1)	3.0 (0.5)	Reference	…	−1.0 (−1.1 to −0.8)	<0.001#	10 (12.8)	68 (87.2)	0 (0.0)
6–<12 mo	40 (33.9)	3.6 (0.8)	0.5 (0.2 to 0.8)	0.001#	−0.5 (−0.7 to −0.2)	0.002#	10 (25.0)	24 (60.0)	6 (15.0)
Chest compression depth target of 5 cm ±10%
1–<3 y	24 (37.5)	4.0 (0.8)	0.0 (−0.7 to 0.6)	0.933	−1.0 (−1.3 to −0.6)	<0.001#	7 (29.2)	17 (70.8)	0 (0.0)
3–<5 y	11 (17.2)	4.1 (1.1)	Reference	…	−0.9 (−1.6 to −0.2)	0.017#	4 (36.4)	6 (54.6)	1 (9.1)
5–<8 y¶	16 (25.0)	4.1 (0.8)	0.0 (−0.8 to 0.7)	0.980	−0.9 (−1.4 to −0.5)	0.001#	7 (43.8)	9 (56.3)	0 (0.0)
8–12 y	13 (20.3)	5.2 (1.3)	1.2 (0.1 to 2.2)	0.030#	0.2 (−0.6 to 1.1)	0.527	7 (53.9)	3 (23.1)	3 (23.1)

APD indicates anterior–posterior diameter.

^*Difference in mean one‐third APD between age subgroups.

^† Mean one‐third APD minus absolute age‐specific chest compression depth targets (infants 4 cm, children 1–12 years old 5 cm).

^‡ Patients' one‐third APD within 10% of chest compression depth target of 4 cm (3.6–4.4 cm) in infants and 5 cm (4.5–5.5 cm) in children according to age subgroups.

^§ Patients' one‐third APD <3.6 cm in infants and <4.5 cm in children according to age subgroups.

^|| Patients' one‐third APD >4.4 cm in infants and >5.5 cm in children according to age subgroups.

^¶ No significant difference if the 5‐ to <8‐year‐old subgroup was the reference age group for the subgroup analyses.

^# Significant P values (<0.05).

For children 1 to 12 years old, subgroup analysis by age demonstrated that only the 8‐ to 12‐year‐old age group had a mean one‐third APD (5.2 cm; SD, 1.3) that was not significantly different from the 5 cm chest compression depth target (difference, 0.2 [95% CI, −0.6 to 1.1]). The mean one‐third APD of the rest of the younger children (<8 years old) was smaller than the 5 cm chest compression depth target. This is illustrated in Figure 2.

Figure 2. Bee swarm plot of APD according to age subgroup.

APD indicates anterior–posterior diameter.

Fractional polynomial regression scatter plots of one‐third APD on age (as a continuous variable) of infants and children were linear, as shown in Figure S2A and S2B, respectively. Fractional polynomial regression of concordance and difference between the 2 chest compression targets on age also suggested linear associations. For the infants, the associated odds ratio for concordance was 1.22 (95% CI, 1.04–1.43; P=0.015), and the associated coefficient for the difference between one‐third APD and their absolute chest compression depth target was 0.09 (95% CI, 0.05–0.13; P<0.001). For the children, the associated odds ratio for concordance was 1.15 (95% CI, 0.97–1.36; P=0.110), and the associated coefficient for the difference between one‐third APD and their absolute chest compression depth target as an outcome was 0.15 (95% CI, 0.06–0.23; P=0.001).

There were no significant differences between the mean one‐third APD of infants and children between the sexes (Table S2) and among White, Asian, and Black race categories (Table S3). The mean one‐third APD across the sexes and 3 races were significantly smaller than their age‐specific absolute chest compression depth targets (Tables S2 and S3).

Sensitivity analyses demonstrated that only age, in both infants and children, was consistently associated with the difference between the chest compression depth targets and one‐third APD. Please refer to Tables S4 through S7.

Discussion

We present the first clinical study that compares direct APD measurements with absolute age‐specific compression depth targets in a multiracial cohort of children experiencing cardiac arrest. We found poor concordance between measured one‐third APD and absolute age‐specific chest compression depth targets, especially for infants and younger children.

For the majority of pediatric cardiac arrest events, rescuers would not usually be able to accurately measure actual depth of compressions rendered and can, at best, only estimate visually the proportion of APD to compress or estimate the depth they compressed. Generally, we advocate for push hard and push fast during pediatric cardiac arrest, because observation studies have shown that most chest compressions rendered to pediatric patients in cardiac arrest did not reach recommended absolute chest compression depth targets. ¹¹ , ¹⁴ This may be especially important in dispatching pediatric life support instructions. ¹⁵ However, the relevance of our study's findings may not be just academic. With CPR, quality feedback devices, especially those with dual sensors (anterior and posterior), can accurately measure chest compression depths in infants and children. More recent studies on CPR coaching with dual‐sensor CPR quality feedback devices had demonstrated that chest compression depth targets can be realistically achieved with high compliance rates, especially with training. ¹⁶ , ¹⁷ , ¹⁸

Although there have been minor variations in the use of relative chest compression depth targets of at least and approximately one‐third APD chest depth in the past, ⁷ most resuscitation councils have advocated the chest compression target of at least one‐third APD chest depth in their most recent recommendations. ⁸ , ⁹ If age‐specific absolute chest compression depth targets would result in better hemodynamics or clinical outcomes, based on our study, the use of at least one‐third APD chest depth would mean that potential undercompression would occur at the lower limits of a relative chest compression target of one‐third APD, especially for infants, younger, and nonoverweight children. For our infant population, their one‐third APD measurements were significantly smaller than the chest compression target of 4 cm at −0.8 cm (95% CI, −0.9 to 0.7). This was especially marked in those <6 months old (n=78), the biggest cohort across age subgroups. Their mean one‐third APD was significantly less than the 4 cm chest compression depth target by −1 cm (95% CI, −1.1 to −0.8), and in most of these younger infants’ (87.2%), their one‐third APD was <3.6 cm (lower limit of the 4 cm chest compression depth target). This age‐dependent difference was also demonstrated in fractional polynomial regression scatter plots (Figure S2A) and regression analyses (Table S5). As such, if chest compressions were rendered at one‐third APD, most infants would not have reached the recommended chest compression target of ≈4 cm. Similarly, for children <8 years old and those who were nonoverweight, the implications would be the similar in that undercompression could potentially occur in most of the children if chest compressions were at one‐third APD.

Conversely, if one‐third APD chest compression depth targets would result in better hemodynamics or clinical outcomes, there could be potential overcompression, especially for infants. Although there are no pediatric studies looking at the adverse effects of overcompression, a forensic study in adults observed increased rates of chest compression‐related injuries if compressions of >6 cm were delivered. ¹⁹ If overcompression occurred in pediatric patients with cardiac arrest, there could be potentially similar concerns. This would be especially so for infants <6 months old.

However, although it is unknown which chest compression depth target is superior, the 2 were not concordant for a majority of the studied population. For councils that recommend approximately and not at least one‐third APD, the difference between the relative and absolute chest compression depth targets would be more pronounced.

There is evidence that indicate current pediatric absolute age‐specific chest compression depth targets need clinical validation. The earlier 2 pediatric observational clinical studies ⁵ , ⁶ that informed current absolute pediatric chest compression guidelines ¹ , ⁸ , ⁹ were based on single‐sensor CPR quality feedback devices that could have potentially overestimated compression depths due to compression on nonfirm surfaces and patient movement. It was notable that the more recent observational studies using the more advanced dual‐sensor CPR quality feedback devices ¹¹ , ¹⁴ reported these recommended absolute depth targets were rarely achieved in clinical practice without CPR coaching and training. Two large observational adult cardiac arrest studies by Duval et al and Stiell et al observed that the optimal compression depth associated with neurological favorable survival after adjusting for confounders were 4.7 cm and 4.56 cm, respectively. ²⁰ , ²¹ In pediatrics, the recommendations of chest compression depth target of ≈5 cm, especially for younger children, should be further validated, because this would be similar to the optimal chest depth compression depths reported in the 2 adult studies. In a pediatric experimental study using piglet models simulating toddlers, hemodynamic‐guided chest compressions led to mean chest compression depths at 4 cm, and had better survival outcomes compared with when chest compressions were randomized to receive standardized chest compressions of 5 cm. ²² Ong et al reported in a pediatric radiologic study that simulated chest compressions ≥4 cm and beyond their one‐third APD could potentially result in potential overcompression in a significant proportion of the infant cohort. ²³

Limitations

There was no interrater reliability assessment performed for the APD measurements taken. However, the difference between the mean one‐third APD in our study and age‐specific absolute depth targets was consistently around 1 cm, which was less likely to be solely attributable to potential minor variations in measurements, especially for the infant group.

Most of the pediatric patients with cardiac arrest had their APD measured after chest compressions were performed. It was unknown if chest compressions resulted in acquired chest deformity especially in infants, which might have potentially affected APD measurements.

Lastly, this observational study did not investigate if there were associated differences in clinical outcomes if the mean chest compression depth rendered during pediatric cardiac arrest were closer to their one‐third APD when compared with the recommended absolute age‐specific chest compression depth targets.

Conclusions

There was poor concordance between one‐third APD and age‐specific absolute chest compression depth targets, especially for the infants who were <6 months old. The one‐third APD of the majority of infants and children who were <8 years old or who were not overweight was significantly lower than their age‐specific chest compression depth targets of ≈4 and 5 cm, respectively. Current chest compression depth target recommendations should be validated in clinical studies, and the optimal chest compression depth to improve neurologically intact survival should be further researched.

Sources of Funding

The pediRES‐Q Collaborative is supported by an unrestricted research grant to the Children's Hospital of Philadelphia from ZOLL Medical Corporation. The sponsor had no role in the design, interpretation, writing, editing, or submission of the article.

Disclosures

Dr Nadkarni received unrestricted research funding to his institution from the National Institutes of Health, Agency for Healthcare Research and Quality, ZOLL Medical Corporation, Nihon‐Kohden Inc., and Volunteers on Scientific Advisory Committees for the American Heart Association, Citizen CPR Foundation, INSPIRE simulation research network, and Citizen CPR. Dr Nadkarni is the President of the Society of Critical Care Medicine 2022 to 2023. The content reflects his own personal work and is not intended to represent the views of the Society of Critical Care Medicine. D. Niles disclosed that the Children's Hospital of Philadelphia receives support from an unrestricted research grant from ZOLL Medical Corporation. The remaining authors have no disclosures to report.

Supporting information

Data S1–S2

Tables S1–S7

Figures S1–S2

References ²⁴ , ²⁵ , ²⁶