This study aimed to compare the optimal chest compression depth for infants and children with that of adults when the simulated compression depth was delivered according to the current guidelines.
A total of 467 consecutive chest computed tomography scans (93 infants, 110 children, and 264 adults) were reviewed. The anteroposterior diameter and compressible diameter (CD) for infants and children were measured at the inter-nipple level and at the mid-lower half of the spine for adults. Compression ratio (CR) to CD was calculated at simulated 1/4, 1/3, and 1/2 antero-posterior compressions in infants and children, and simulated 5- and 6-cm compressions in adults.
In adults, the CRs to CD at simulated 5- and 6-cm compression depth were 41.7±0.16%, 50.0±7.3% respectively. In children and infants, the CRs to CD at 1/3 chest compression were 55.1±2.4% and 51.8±2.4%, respectively, and at 1/2 chest compression, CRs were 82.7±3.7% and 77.7±3.6%, respectively. The CRs to CD of 4-cm compression depth in infants and 5-cm compression depth in children were 74.4±10.9%, 62.5±8.7%, respectively. The CRs to CD for children and infants were significantly higher than in adults (P<0.001). The CR to CD of 4-cm compression depth in children was almost similar to that of 6-cm compression depth in adults (50.0± 6.9% vs. 50.0±7.3%, P=0.985).
Current pediatric guidelines for compression depth are too deep compared to those in adults. We suggest using 1/3 of the anteroposterior chest diameter or about 4 cm in children and less than 4 cm in infants.
Excessive chest compression may cause serious mechanical complications.
Current cardiopulmonary resuscitation guideline which recommend optimal depth in infants and children as over 1/3 depth of anteroposterior diameter seemed to be too deep comparing with the guideline of adults.
Closed-chest compression—a crucial factor during cardiopulmonary resuscitation (CPR)—is related to cardiac output and coronary perfusion pressure, and can directly affect a victim’s survival. It has been well established in previous studies that proper chest compression is highly associated with high survival rates of cardiac arrest patients [
Some studies have investigated optimal compression depth to prevent serious complications from too deep compressions; however, there is a lack of evidence for optimal chest compression depth for infants and children CPR, therefore guidelines are not been well established for these populations [
The purpose of this study was to evaluate the accuracy of the 2010 AHA guideline recommendation for correct compression depth for infants and children, and assess the optimal depth for infants and children by comparing the depth rate of adults and children with the computed tomography (CT) analysis.
This retrospective study used radiographic data from 206 children aged 0 to 8 years who were tested by using chest CT between January 2010 and December 2013. Children with pectus excavatum, chest/lung hypoplasia (n=3) were excluded resulting in a total of 203 children that were included in this study. In addition, 264 non-traumatic adult patients who were tested by using chest CT were enrolled in the study for the comparison.
The anteroposterior diameter (APD) of the thorax was measured by cross-section analysis of the chest CT. According to the 2010 AHA guidelines, APDs were measured below the spine across the nipple line in infants. For children, APDs were measured at the mid-lower portion of the spine [
Statistical analyses were performed using IBM SPSS Statistics ver. 21.0 (IBM Corp., Armonk, NY, USA). Normally distributed data were presented as mean and standard deviation, and the independent Student’s t-tests was used to compare normally distributed data between the 2 groups, and one-way ANOVA was used among the 3 groups. An alpha level of 0.05 for this two-tailed test was considered statistically significant.
Enrolled subjects (n=467) included 93 infants, 110 children, and 264 of adults. The mean age was approximately 4 months in the infants, 4.3 years in the children, and 41.5 years in the adults. The percentage of male subjects was 50.5%, 60.0%, and 58.7% in the infants, children, and adults, respectively (
There was no significant difference in APD between the male and female infants (87.9 vs. 83.9 mm, P=0.243) (
In children, the chest was compressed at 41.3% of CR in both sexes when compression depth was 1/4 of APD. When compression depth was 1/3 of APD, the chest was compressed at 55.1% of CR in both sexes. When compression depth was 1/2 of APD, the chest was compressed at 82.7% of CR in both sexes.
Because CR for APD in children was smaller than that in infants (60.6% vs. 64.4%), higher CR was shown in the children.
When compression depth was 4 cm in the infant according to 2010 AHA guideline, the chest was compressed at 72.9% of CR in males and 75.9% of CR in females. When compression depth was 5 cm in children, the chest was compressed at 36.9% of APD in males and 39.5% of APD in females. CR was 60.2% of APD in males and 66.1% of APD in females (
The CR of APD was compared with 1/4, 1/3, 1/2 depth of infants and children, 4 cm depth in infants, and 5 cm depth in children to that of 6 cm depth in adults. The CR of APD in 1/3 and 1/2 depth in infants and children was higher than that in 6 cm depth in adult (P<0.001). The CR of APD in 4 cm depth in infants and 5 cm depth in children was higher than that in 6 cm depth in adults as well (P<0.001). The CR in 1/2 depth in children is highest among all calculated CRs, and CR in 1/2 depth in infants, 4 cm depth in infants, 5 cm depth in children, 1/3 depth in children, 1/3 depth in infants, 6 cm depth in adults, and 5 cm depth in adults were followed in order. Otherwise there was no difference in CR of APD between the 5 cm depth and 1/4 depth in children (41.7% vs. 41.3%, P=0.563).
When compression depth was 1/2 of APD in infant, residual CD was less than 1 cm in 10 (10.8%) patients, and others showed less 2 cm of residual CD. When compression depth was 1/3 and 1/4 of APD, all residual CDs were higher than 2 cm. However, when compression depth was 4 cm of APD in infants, residual CD was less than 1 cm in 35 (37.6%) patients. Too deep compressions may be delivered when a rescuer compresses the chest with 4 cm depth of APD according to the 2010 AHA guidelines in infants.
When the compression depth was 1/2 of APD in children, the residual CD was less than 1 cm in 19 (17.3%) patients, and 81 (73.6%) showed 1 to 2 cm of residual CD. When rescuers compressed the chest with 5 cm depth of APD in children according to the 2010 AHA guidelines, the residual CD was less than 1 cm in only 1 patient, but 19 showed 1 to 2 cm of residual CD.
This study analyzed the real CDs and CRs in various recommendations for compression depth after dividing by compression possible diameter and compression impossible diameter using the chest CT. Some previous studies sought to determine the optimal chest compression depth. However, the study samples were too small and included mainly western populations, and did not consider the anatomical compression depth that could not be compressed [
This study showed the approximate APD of chest and values of CRs in adults, children, and infants. There was no significant difference in the CR for total APD between males and females despite significant differences in APD and CRs between children and adults. This may be used as a guideline for comparing the corrected depth of chest compression between male and female subjects. There was a significant difference in the CR for APD among each population. The CR in children was similar to that in adults but smaller than that in infants; therefore, deeper chest compressions may be delivered in children than in infants if chest compressions are performed according to the guideline of constant CR for APD. Thoracic spine growth is faster in children compared to that in infants; therefore, CR for APD may be lower in children than in infants.
The 2010 AHA CPR guideline recommends that optimal chest compression depth should be over 5 cm, and 2010 European Resuscitation Council CPR guideline recommends that corrected compression depth is 5 to 6 cm [
In comparison between adults and infants using the calculation of CR for CD, 1/3 depth of infant was matched well with 6 cm depth of adult. There was similar CR in both groups (51.8% vs. 50.0%), however statistically deeper compressions were delivered in 1/3 depth of infants than in adults with 6 cm depth.
In children, CR in 1/3 of depth was higher than in adults with 6 cm depth (55.1% vs. 50.0%). Relatively more forceful compressions were delivered in the children. In addition, CR in children with 5 cm depth was 62.5%. Approximately 1.2 times of compression depth in adults with 6 cm depth (62.5%) were delivered in the children. If the 4 cm depth compared to the infant guideline was delivered in children, CR was matched well with that in 6 cm depth of adults (50.0%). The guideline of 4 cm depth in children seemed to be well correlated with the adult guidelines.
In this study, we defined that too deep compressions can cause mechanical injury as residual CD of lesser 2 cm after chest compressions, because the sum of the total thorax wall and total APD of heart was measured as 2 cm. Therefore, chest compressions, which can reduce residual CD by 2 cm may cause the cardiac contusions and possible impaired cardiac function after recovery of spontaneous circulations. This is because of the high possibility of direct collision between the anterior and posterior walls of the heart.
When the compression depth is 4 cm in infants, the mean residual CD was 15 mm and lesser than 2 cm of residual CD occurred in 71% among them. This means that chest compression with 4 cm depth in infants was too deep and may lead to a high risk of fatal internal organ damage. When the compression depth is 1/2 of APD in infants, lesser than 2 cm of residual CD occurred in most infants. Otherwise when compression depth is 5 cm in children, lesser than 2 cm of residual CD occurred in 20 (18.2%) of which, all were lesser than 2 years old, except in one child. This may be because some children have a body frame similar to that of infants. We could therefore consider that the infant guidelines may be more useful in children younger than 2 years. If the compression depth is 1/2 of APD in children, the residual CD was 2 cm less occurred in 99 (90.0%). This guideline may lead to a high risk of fatal internal organ damage in infants.
When the compression depth is 1/4 of APD in children and infants, CR for CD was lesser than that in adults with 6 cm depth, but similar to that in the adults with 5 cm depth (5 cm in adults vs. 1/4 of children vs. 1/4 of infants was 41.7% vs. 41.3% vs. 38.9%).
This result was well correlated with those of other previous studies, which demonstrated that 1/2 depth of APD seemed to be too deep [
According to the 2010 CPR guideline, the more forceful, faster, and over 1/3 depth, deeper chest compressions than 1/3 depth of APD may be delivered. Chest compressions with 1/2 depth of APD may be delivered in some small infants or children because there was scant difference between the 1/2 depth and 1/3 depth. Therefore, the current guideline of over 1/3 compression depth in children and infants may lead to too deep and forceful compression and fatal internal organ injury in some patients; this is because the guidelines did not consider variations in patients anatomy and the strength of the person providing compression. Some modification of guidelines for reliable compression depth in infant and children are needed in the future.
This study showed that 4 cm depth of children had similar CR with that in adult with 6 cm depth. We believed that the guideline of 4 cm depth in children seemed to be more suitable than previous guideline of 5 cm depth, and over 1/4 depth of APD may also be more suitable than 1/3 depth. Along with the case of children, too deep chest compressions were delivered according to the current 2010 guideline in infants. Guideline of 1/4 to 1/3 in infant seemed to be more suitable than the previous guideline of over 1/3 depth.
The study has limitations. First, this study was retrospectively performed in one university hospital. The sample size was small and study result may be limited to generalize the fact. Second, mainly patients were enrolled. Healthy subjects were not enrolled; relatively small sized subjects who were chronically or acutely ill were included. However, we excluded children with congenital chest anomalies and most children had mainly pneumonia or aortic disease, which may reduce the bias. Third, there was possible bias of measuring the diameter form variance of respirations. There was some difference in chest diameter between the inspiration and expiration. This difference may be small because of small tidal volume in infants and children. Fourth, the mean age of the infants was 4 months. Many small infants were included, the measured APD may be small.
The current 2010 CPR guideline, which recommends optimal depth in infants and children as over 1/3 depth of APD (4 cm in infants and 5 cm in children) seems to be too deep when compared to adult guidelines. Therefore, chest compressions under the 2010 guideline may cause fatal internal organ damage. Considering the adult guidelines, lesser than 1/3 depth of APD (4 cm) seemed to be more suitable in children and lesser than 1/3 depth of APD seemed to be more suitable in infants to avoid serious internal organ injury.
No potential conflict of interest relevant to this article was reported.
This work was supported by grant number R000122311 from Dankook University.
Computed tomography scan demonstrating axial image at the mid sternal level and method for calculating compressible, incompressible diameter and antero-posterior diameter. We calculated the compressible diameter by measuring a line drawn perpendicularly from the skin anteriorly to the anterior vertebral body.
General characteristics of the subjects
Group | No. | Male | Age (yr) |
---|---|---|---|
Infant (≤ 1 yr) | 93 | 47 (50.5) | 0.31 ± 0.34 |
Child (> 1 and ≤ 8 yr) | 110 | 66 (60.0) | 4.3 ± 2.1 |
Adult (≥ 18 yr) | 264 | 155 (58.7) | 41.5 ± 11.9 |
Values are presented as n (%) or mean±standard deviation.
APD and CD according to the subgroup
Group | Variable | Total |
Male | Female | P-value |
---|---|---|---|---|---|
Infant | APD (mm) | 85.9 ± 16.3 | 87.9 ± 17.0 | 83.9 ± 15.4 | 0.243 |
CD (mm) | 55.1 ± 9.0 | 56.4 ± 9.8 | 53.8 ± 8.0 | 0.166 | |
CD/APD (%) | 64.4 ± 2.8 | 64.4 ± 2.4 | 64.5 ± 3.3 | 0.915 | |
Child | APD (mm) | 134.3 ± 16.8 | 138.6 ± 17.1 | 128.0 ± 14.3 | < 0.001 |
CD (mm) | 81.5 ± 11.5 | 84.5 ± 11.1 | 77.1 ± 10.8 | < 0.001 | |
CD/APD (%) | 60.6 ± 2.6 | 61.0 ± 2.2 | 60.1 ± 2.6 | 0.082 | |
Adult | APD (mm) | 206.8 ± 22.5 | 212.2 ± 19.4 | 199.1 ± 24.3 | < 0.001 |
CD (mm) | 122.3 ± 16.5 | 125.3 ± 14.8 | 118.1 ± 18.0 | < 0.001 | |
CD/APD (%) | 59.0 ± 2.9 | 58.9 ± 2.7 | 59.1 ± 3.1 | 0.527 |
Values are presented as mean±standard deviation. CD/APD showed statistically significant difference between infant vs child, child vs adult, and infant vs adult (All P<0.001).
APD, anteroposterior diameter; CD, compressible diameter.
Male and female.
Comparison between male and female using t-test.
Compression diameter according to 1/4, 1/3, and 1/2 compression depth of APD in pediatric patients
Group | Compression depth (mm) | Total |
Male | Female | P-value |
---|---|---|---|---|---|
Infant | 1/4 of APD | 21.5 ± 4.1 | 22.0 ± 4.3 | 21.0 ± 3.9 | 0.243 |
1/3 of APD | 28.6 ± 5.4 | 29.3 ± 5.7 | 28.0 ± 5.1 | 0.242 | |
1/2 of APD | 43.0 ± 8.1 | 43.9 ± 8.5 | 41.9 ± 7.7 | 0.243 | |
Child | 1/4 of APD | 33.6 ± 4.2 | 34.6 ± 4.3 | 32.0 ± 3.6 | 0.001 |
1/3 of APD | 44.8 ± 5.6 | 46.2 ± 5.7 | 42.7 ± 4.7 | 0.001 | |
1/2 of APD | 67.2 ± 8.4 | 69.3 ± 8.5 | 64.0 ± 7.1 | 0.001 |
Values are presented as mean±standard deviation.
APD, anteroposterior diameter.
Male and female.
Comparison between male and female using t-test.
Compression ratios to the CDs according to 1/4, 1/3, and 1/2 compression depth of APD in pediatric patients
Group | Compression ratio (%) | Total |
Male | Female | P-value |
---|---|---|---|---|---|
Infant | 1/4 of APD to CD | 38.9 ± 1.8 | 38.9 ± 1.5 | 38.9 ± 2.1 | 0.978 |
1/3 of APD to CD | 51.8 ± 2.4 | 51.8 ± 2.0 | 51.8 ± 2.7 | 0.991 | |
1/2 of APD to CD | 77.7 ± 3.6 | 77.7 ± 2.9 | 77.7 ± 4.1 | 0.994 | |
Child | 1/4 of APD to CD | 41.3 ± 1.8 | 41.1 ± 1.5 | 41.7 ± 2.2 | 0.067 |
1/3 of APD to CD | 55.1 ± 2.4 | 54.8 ± 2.0 | 55.6 ± 2.9 | 0.067 | |
1/2 of APD to CD | 82.7 ± 3.7 | 82.1 ± 3.0 | 83.4 ± 4.4 | 0.068 |
Values are presented as mean±standard deviation.
CD, compressible diameter; APD, anteroposterior diameter.
Male and female.
Comparison between male and female using t-test.
Compression ratios to APD and CD of the several recommended compression depths according to groups
Group | Compression ratio (%) | Total |
Male | Female |
---|---|---|---|---|
Infant | 4 cm to APD | 48.1 ± 8.0 | 47.1 ± 8.2 | 49.1 ± 7.6 |
4 cm to CD | 74.4 ± 10.9 | 72.9 ± 11.4 | 75.9 ± 10.2 | |
Child | 5 cm to APD | 37.8 ± 4.5 | 36.6 ± 4.4 | 39.5 ± 4.1 |
5 cm to CD | 62.5 ± 8.7 | 60.2 ± 7.9 | 66.1 ± 8.7 | |
Adult | 5 cm to APD | 24.5 ± 2.8 | 23.7 ± 2.2 | 25.5 ± 3.2 |
5 cm to CD | 41.7 ± 6.1 | 40.5 ± 4.9 | 43.4 ± 7.1 | |
6 cm to APD | 29.4 ± 3.4 | 28.5 ± 2.6 | 30.6 ± 3.9 | |
6 cm to CD | 50.0 ± 7.3 | 48.6 ± 5.9 | 52.1 ± 8.5 |
Values are presented as mean±standard deviation.
APD, anteroposterior diameter; CD, compressible diameter.
Male and female.
Comparison of the CRs between pediatrics and adult
Group | CR (%) | Mean ± SD | Adult |
P-value |
|
---|---|---|---|---|---|
CR of 6 cm to CD | CR of 5 cm to CD | ||||
Infant | 1/4 of APD to CD | 38.9 ± 1.8 | - | 41.7 ± 6.1 | < 0.001 |
1/3 of APD to CD | 51.8 ± 2.4 | 50.0 ± 7.3 | - | < 0.001 | |
1/2 of APD to CD | 77.7 ± 3.6 | 50.0 ± 7.3 | - | < 0.001 | |
4 cm to CD | 74.4 ± 10.9 | 50.0 ± 7.3 | - | < 0.001 | |
Child | 1/4 of APD to CD | 41.3 ± 1.8 | - | 41.7 ± 6.1 | 0.563 |
1/3 of APD to CD | 55.1 ± 2.4 | 50.0 ± 7.3 | - | < 0.001 | |
1/2 of APD to CD | 82.7 ± 3.7 | 50.0 ± 7.3 | - | < 0.001 | |
5 cm to CD | 62.5 ± 8.7 | 50.0 ± 7.3 | - | < 0.001 | |
4 cm to CD | 50.0 ± 6.9 | 50.0 ± 7.3 | - | 0.985 |
CR, compression ratio; SD, standard deviation; CD, compressible diameter; APD, anteroposterior diameter.
Comparison between infant or child and adult using t-test.
Residual compressible diameter according to compression depths
Group | Compression depth | Residual compressible diameter |
||
---|---|---|---|---|
Mean ± SD (mm) | < 1 cm, n (%) | 1-2 cm, n (%) | ||
Infant | 1/4 of APD | 33.6 ± 5.1 | 0 | 0 |
1/3 of APD | 26.4 ± 3.9 | 0 | 0 | |
1/2 of APD | 12.1 ± 2.2 | 10 (10.8) | 83 (89.2) | |
4 cm | 15.1 ± 9.0 | 35 (37.6) | 31 (33.3) | |
Child | 1/4 of APD | 47.9 ± 7.6 | 0 | 0 |
1/3 of APD | 36.7 ± 6.4 | 0 | 0 | |
1/2 of APD | 14.4 ± 4.2 | 19 (17.3) | 81 (73.6) | |
4 cm | 41.5 ± 11.5 | 0 | 1 (0.9) | |
5 cm | 31.5 ± 11.5 | 1 (0.9) | 19 (17.3) |
APD, anteroposterior diameter; SD, standard deviation.