The uniform chest compression depth of 50 mm or greater recommended by current guidelines is not appropriate for all adults

Influence of patient body weight on the probability of return of spontaneous circulation following out-of-hospital cardiac arrest: an exploratory analysis

Introduction

In addition to key interventions, including bystander CPR and defibrillation, successful resuscitation of out-of-hospital cardiac arrest (OHCA) is also associated with several patient-level factors, including a shockable presenting rhythm, younger age, Caucasian race and female sex. An additional patient-level factor that may influence outcomes is patient weight, yet this attribute has not been extensively studied within the context of OHCA, despite globally increasing obesity rates.

Objective

To assess the relationship between patient weight and return of spontaneous circulation (ROSC) during OHCA.

Methods

This retrospective study included adult patients from a national emergency medical services (EMS) patient record, with witnessed, non-traumatic OHCA prior to EMS arrival from January to December 2020. Logistic regression was used to evaluate the relationship between patient weight and ROSC.

Results

Complete records were available for 9096 patients, of which 64.3% were males and 25.3% were ethnic minorities. The mean age of the participants was 65.01 years (SD = 15.8), with a mean weight of 93.52 kg (SD = 31.5). Altogether, 81.8% of arrests were of presumed cardiac aetiology and 30.3% presented with a shockable rhythm. Bystander CPR and automated external defibrillator (AED) shock were performed in 30.6% and 7.3% of cases, respectively, and 44.0% experienced ROSC. ROSC was less likely with patient weight >100 kg (OR = 0.709, p <0.001), male sex (OR = 0.782, p <0.001), and increasing age and EMS response time (OR = 0.994 per year, p <0.001 and OR = 0.970 per minute, p <0.001, respectively). Patients with shockable rhythms were more likely to achieve ROSC (OR = 1.790, p <0.001), as were patients receiving bystander CPR (OR = 1.170, p <0.001) and defibrillation prior to EMS arrival (OR = 1.658, p <0.001). Although the mean first adrenaline dose (mg/kg) followed a downward trend due to its non-weight-based dosing scheme, the mean total adrenaline dose administered to achieve ROSC demonstrated an upward linear trend of 0.05 mg for every 5 kg of body weight.

Conclusions

Patient weight was negatively associated with ROSC and positively associated with the total adrenaline dose required to attain ROSC.

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.

An Evaluation of the Quality of CPR Chest Compressions Performed on Football-Equipped and Obese Simulation Manikins

OBJECTIVE

Protective athletic equipment may hamper the delivery of effective chest compressions. Unfortunately, an algorithm for managing cardiac arrest emergencies with equipment-laden athletes has yet to be established by national CPR certifying agencies. Further, athletes classified as being overweight or obese carry adipose in the thoracic region, which has been reported to inhibit the ability of rescuers to provide quality chest compressions. Thus, the purpose of this study was two-fold. The first purpose was to assess the ability of emergency responders to perform CPR chest compressions on an obese manikin. The second purpose was to analyze the effect of American football protective equipment on the performance of chest compressions by emergency responders.

METHODS

Fifty emergency responders completed four 2-minute bouts of compression-only CPR. The scenarios included performing chest compressions on both traditional and obese CPR manikins, and performing chest compressions over a set of shoulder pads/chest protector that is used in the sport of American football on both traditional and obese manikins.

RESULTS

The most notable outcomes in this study were related to chest compression depth, which fell well below the minimum recommended depth published by the American Heart Association in all conditions. Mean compression depth was significantly lower when performed on the obese manikin (avg over pads = 32.8, SD = 9.2 mm; avg no pads = 38.2, SD = 9.1 mm) compared to the traditional manikin (avg over pads = 40.0, SD = 10.9 mm; avg no pads = 40.8, SD = 14.8 mm), with statistical analyses revealing a significant effect due to both manikin size (p < 0.001) and the presence of equipment (p = 0.003), and a statistically significant interaction effect (p = 0.035). Chest recoil data revealed a statistically significant effect due to both manikin size (p = 0.017) and the presence of chest/shoulder safety pads (p = 0.003).

CONCLUSION

Within this sample of emergency responders, chest compressions were adversely affected both by the equipment and obesity. Additionally, the traditional manikin received comparable chest compressions regardless of the presence or absence of football protective equipment, albeit both conditions resulted in poor depth performance.

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.

The effects of thoracic cage dimension and chest subcutaneous adipose tissue on outcomes of adults with in-hospital cardiac arrest: A retrospective study

BACKGROUND

The associations between thoracic cage dimension, chest subcutaneous adipose tissue (SAT) depth and outcomes of adults with in-hospital cardiac arrest (IHCA) remain unknown.

METHODS

We retrospectively evaluated IHCA patients between January 2016 and October 2017. The thoracic cage transverse diameter, internal AP diameter, cross-sectional area, anterior and posterior SAT depths were measured in computed-tomography (CT) images. Using logistic regression models, we determined the adjusted associations between thoracic cage dimension, SAT depths and the prognosis for IHCA. The primary outcome was sustained return of spontaneous circulation (ROSC) and the secondary outcome was survival to hospital discharge.

RESULTS

Among 423 IHCA patients, 258 patients achieved ROSC and 70 survived to discharge. Smaller cross-sectional area and posterior SAT depth were significantly related to ROSC. Smaller posterior SAT depth was associated with ROSC. After multivariate adjustment, the smaller cross-sectional area was independently associated with ROSC (Odds ratio [OR] 0.99, 95% confidence interval [95%CI] 0.99-1.00; p = 0.008) and survival to discharge (OR 0.99, 95%CI 0.98-1.00; p = 0.024), and the smaller posterior SAT depth was independently related to ROSC (OR 0.65, 95%CI 0.44-0.96; p = 0.030), whereas no relation to survival to discharge was found.

CONCLUSIONS

In adults with IHCA, the smaller thoracic cage dimension and posterior SAT depth are associated with better survival. An adjustable compression depth based on the thoracic cage dimension might be better than the "one-size-fits-all" compression depth for resuscitating CA patients. In addition, physicians should pay extra attention to compression efficacy when resuscitating obese patients.

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.

Associations between body size and outcomes of adult in-hospital cardiac arrest: A retrospective cohort study

AIM

Animal studies have demonstrated that hemodynamic-directed cardiopulmonary resuscitation (CPR) improves outcomes following cardiac arrest compared with the "one-size-fits-all" algorithm. We investigated whether body size of patients is correlated with outcomes of in-hospital cardiac arrest (IHCA).

METHODS

A retrospective study in a single centre was conducted. Adult patients experiencing IHCA between 2006 and 2015 were screened. Body mass index (BMI) was calculated using body weight and height measured at hospital admission. Thoracic anteroposterior diameter (APD) was measured by analysing computed tomography images. Multivariate logistic regression analysis was used to study the associations between independent variables and outcomes. Generalised additive models were used to identify cut-off points for continuous variables.

RESULTS

A total of 766 patients were included, and 60.4% were male. Their mean age was 62.8 years. Mean BMI was 22.9 kg/m², and the mean thoracic APD was 21.4 cm. BMI > 23.2 kg/m² was inversely associated with a favourable neurological outcome (odds ratio [OR]: 0.30, 95% confidence interval [CI]: 0.13-0.68; p-value = 0.004), while thoracic APD was not. When the interaction term was analysed, BMI > 23.2 (kg/m²) × thoracic APD > 18.5 (cm) was inversely associated with both a favourable neurological outcome (OR: 0.33, 95% CI: 0.16-0.69; p-value = 0.003) and survival to hospital discharge (OR: 0.46, 95% CI: 0.26-0.81; p-value = 0.007).

CONCLUSION

Higher BMI and thoracic APD was correlated with worse outcomes following IHCA. For those patients, it might be better to perform CPR under guidance of physiological parameters rather than a "one-size-fits-all" resuscitation algorithm to improve outcomes.

Efficacy of acute care health care providers in cardiopulmonary resuscitation compressions in normal and obese adult simulation manikins

Annually, over 350,000 persons require cardiopulmonary resuscitation (CPR), either in or outside of the hospital. With obesity a rising health issue in the United States, concerns exist regarding the efficacy of quality compressions for CPR in obese patients. The aims of this study were to determine if the compressions for three adult simulation manikins (normal, obese, and morbidly obese) met quality guidelines; to examine any differences in quality of chest compressions performed by health care providers between the three manikins; and to examine the effect of participant characteristics on the quality of chest compressions in obese and morbidly obese manikins. A randomized controlled design was used. Sixty-one health care providers performed chest compressions on the three simulation manikins. Results showed that performance on the normal-sized manikin was significantly better than that on both obese and morbidly obese manikins. Participant characteristics were significantly associated with quality of chest compressions. The effectiveness of compressions in obese and morbidly obese CPR recipients has yet to be determined.

Training in cardiopulmonary resuscitation provided by medical students, residents and specialists: A non-inferiority trial

Introduction:

No definitive answer has been given to the question ‘who should teach cardiopulmonary resuscitation?’ Healthcare professionals and high school teachers are mostly the trainers, but medical students are increasingly being used for this purpose.

Methods:

We divided 296 high school students in three groups based on trainer professional level. Medical students, anaesthesia and intensive care residents, and anaesthesia and intensive care specialists provided basic life support training. We tested their theoretical knowledge with the help of a multiple-choice question questionnaire and practical abilities with the help of a medical simulator, recording chest compression frequency as the primary outcome parameter.

Results:

The study shows comparable results in all groups, with the exception of the chest compression frequency which was higher in the students’ and residents’ groups (students: 134.7/min ± 14.1; residents: 137.9/min ± 15.9; specialists: 126.3/min ± 19.3). Increased rates were not associated with lower depths (39.0 mm ± 8.2, 40.5 mm ± 9.7, and 38.1 mm ± 8.2), so the quality of compressions provided may be seen as equivalent in all the study groups.

Conclusion:

Our data suggest that medical students may be as effective as anaesthesia and intensive care specialists and residents in cardiopulmonary resuscitation training.

Body mass index and thoracic subcutaneous adipose tissue depth: possible implications for adequacy of chest compressions

Objective

Adequacy of cardiopulmonary resuscitation relies on compression of the thoracic cage to produce changes in intra-thoracic pressures sufficient to generate a pressure gradient. In order to evaluate the efficacy of cardiopulmonary resuscitation in morbid obesity, it is first necessary to determine the depth of thoracic subcutaneous adipose tissue (SAT) and to correlate this with body mass index (BMI).

Results

Computerised-tomography images of the thorax of 55 patients with a diagnosis of obesity or morbid obesity (mean BMI 45.95 kg/m²) were evaluated to determine the depth of SAT at the level at which chest compressions would be applied by a trained rescuer, and correlated with BMI. Mean anterior SAT was 36.53 mm, and mean posterior SAT was 50.73 mm. There was a significant correlation between BMI and anterior and posterior SAT for males (p < 0.05 for both), and females (p < 0.05 for both). The slope of the functions was considered sufficiently close to allow combining the data. This also showed a significant correlation between SAT and BMI (p < 0.01 for both). Both anterior and posterior SAT is correlated with BMI. This data allows development of a model to explore the efficacy of chest compressions in morbid obesity.

Electronic supplementary material

The online version of this article (10.1186/s13104-017-2918-9) contains supplementary material, which is available to authorized users.

CPR performance in the presence of audiovisual feedback or football shoulder pads

Objective

The initiation of cardiopulmonary resuscitation (CPR) can be complicated by the use of protective equipment in contact sports, and the rate of success in resuscitating the patient depends on the time from incident to start of CPR. The aim of our study was to see if (1) previous training, (2) the presence of audiovisual feedback and (3) the presence of football shoulder pads (FSP) affected the quality of chest compressions.

Methods

Six basic life support certified athletic training students (BLS-ATS), six basic life support certified emergency medical service personnel (BLS-EMS) and six advanced cardiac life support certified emergency medical service personnel (ACLS-EMS) participated in a crossover manikin study. A quasi-experimental repeated measures design was used to measure the chest compression depth (cm), rate (cpm), depth accuracy (%) and rate accuracy (%) on four different conditions by using feedback and/or FSP. Real CPR Help manufactured by ZOLL (Chelmsford, Massachusetts, USA) was used for the audiovisual feedback. Three participants from each group performed 2 min of chest compressions at baseline first, followed by compressions with FSP, with feedback and with both FSP and feedback (FSP+feedback). The other three participants from each group performed compressions at baseline first, followed by compressions with FSP+feedback, feedback and FSP.

Results

CPR performance did not differ between the groups at baseline (median (IQR), BLS-ATS: 5.0 (4.4–6.1) cm, 114(96–131) cpm; BLS-EMS: 5.4 (4.1–6.4) cm, 112(99–131) cpm; ACLS-EMS: 6.4 (5.7–6.7) cm, 138(113–140) cpm; depth p=0.10, rate p=0.37). A statistically significant difference in the percentage of depth accuracy was found with feedback (median (IQR), 13.8 (0.9–49.2)% vs 69.6 (32.3–85.8)%; p=0.0002). The rate accuracy was changed from 17.1 (0–80.7)% without feedback to 59.2 (17.3–74.3)% with feedback (p=0.50). The use of feedback was effective for depth accuracy, especially in the BLS-ATS group, regardless of the presence of FSP (median (IQR), 22.0 (7.3–36.2)% vs 71.3 (35.4–86.5)%; p=0.0002).

Conclusions

The use of audiovisual feedback positively affects the quality of the depth of CPR. Both feedback and FSP do not alter the rate measurements. Medically trained personnel are able to deliver the desired depth regardless of the presence of FSP even though shallower chest compressions depth can be seen in CPR with FSP. A feedback device must be introduced into the athletic training settings.

The suprasternal notch as a landmark of chest compression depth in CPR

OBJECTIVE

This study was performed to determine a landmark for chest compression depth for adult cardiopulmonary resuscitation (CPR) using chest computed tomography and to evaluate the validity of the landmark.

METHODS

The external anteroposterior diameters (EAPDs) of each chest at the suprasternal notch (SN) and the lower half (LH) of the sternum were measured. We analyzed the differences in the EAPDs between the LH and the SN in each EAPD group in the LH of the sternum as follows: less than 20.00, 20.00 to 21.99, 22.00 to 23.99, greater than or equal to 24.00. We compared the differences in the EAPDs between the 2 points with 50 mm and the chest compression depth on simulated one-fourth external chest compressions for each EAPD group on the LH of the sternum.

RESULTS

The mean difference in the EAPDs between the SN and the LH was 5.16 ± 0.91 mm. The differences in the EAPDs between the SN and the LH of the sternum with 50 mm did not indicate a significant difference. The mean one-fourth EAPD at the LH of the sternum was 5.50 ± 0.53 mm. There was not a significant difference in the residual chest depth on one-fourth simulated chest compression for each EAPD group on the LH of the sternum.

CONCLUSIONS

The SN may have value as a functional landmark for chest compression depth in adult CPR. Our findings combined with the simulated one-fourth chest compressions were more consistent with the depth between 50 and 60 mm recommended by the 2015 CPR guidelines.