Muscular fitness as a mediator of quality cardiopulmonary resuscitation

Hands-Only Cardiopulmonary Resuscitation Education for Elementary School Students in Korea: Tracking by School Grade, Physical Characteristics, and Physical Strength

Objectives: This study aimed to assess variations in chest compression depth among Korean elementary school students based on grade, physical characteristics, and strength. Methods: The study involved 140 children in the third to sixth grades from elementary schools. Before providing cardiopulmonary resuscitation (CPR) education, we assessed height, weight, BMI, grip strength, and back strength. Subsequently, CPR education was administered, followed by individual measurements of compression depth. The factors related to compression depths was analyzed using t-test, ANOVA and multivariable regression. Results: The mean compression depth was consistently lower than the guideline standard across all grades, indicating grade-dependent differences (p = 0.000). Moreover, height, weight, BMI, grip strength and back strength increased, exhibited significant increases with grade (p = 0.000). In multivariable regression analysis, it was observed that as grade increased, chest compression depth increased by 0.701 cm (p = 0.000). Conclusion: School grade significantly influenced achieving the proper chest compressions depth, no notable correlation found for physical factors. Thus, a strategy emphasizing the importance of sufficient chest compressions during CPR education, particularly targeting elementary school students, seems necessary to encourage greater effort.

CPR quality with rotation of every 1 versus 2 minutes as characteristics of rescuers: A randomized crossover simulation study

BACKGROUND

Fatigue and rotation time are key factors affecting the quality of cardiopulmonary resuscitation (CPR). This study aimed to investigate the effects of rotation time on CPR duration, and sex on chest compression quality.

METHODS

In this randomized crossover simulation study, we enrolled 100 paramedic students stratified by sex and randomly grouped into 28 male and 22 female pairs. In the 2- and 1-minute scenarios, 2 participants performed CPR for 20 minutes with a rotation cycle of 2 minutes and 1 minute, respectively. After taking a break, they changed over and performed CPR again for 20 minutes. The switching of roles was performed with the students positioned on opposite sides of the mannequin. For chest compression quality, a set was defined as CPR performed by 1 pair in a 2-minute scenario for 4 minutes. The quality of CPR in each set was compared between the 2 groups.

RESULTS

The 1-minute group showed significantly higher chest compression depth than the 2-minute group (54.0 [51.5-57.0] vs 52.5 [48.5-56.5] mm, P = .001, respectively). The female 2-minute group showed decreased chest compression depth over time, and the 1-minute group showed significantly increased chest compression depth during all sets except the 2nd set (54.0 [51.9-55.1] vs 50.5 [48.5-53.8] mm [P = .030], 52.3 [49.4-54.5] vs 50.8 [47.0-53.1] mm [P = .080], 52.8 [49.8-54.5] vs 48.8 [45.4-51.6] mm [P = .002], 51.5 [48.5-53.3] vs 48.3 [44.5-50.6] mm [P = .004], and 50.8 [48.9-54.1] vs 47.5 [44.6-50.1] mm [P = .001], respectively). The fatigue scores in the 2-minute group were significantly higher during sets 4 and 5 than those in the 1-minute group.

CONCLUSION

When rescuer fatigue increases during prolonged CPR owing to their physical strength and skill levels, the rotation of rescuers every minute would be helpful in maintaining high-quality CPR.

Association of Training in Basic Life Support with the Evolution of Cardiopulmonary Resuscitation Performed by Firefighters

Introduction

This study aimed to compare the results of professional technical and anthropometric anamnesis data with the transmission of external chest compressions performed by military firefighters at different execution times.

Objective

The objective was to evaluate the performance and perceived effort of the sequence of external chest compressions performed in two minutes, as well as the evolution of the technique over time.

Materials and Methods

This was a descriptive, correlational study involving adult firefighters who were members of a specific firefighter group, comprising a population of 105 individuals with a voluntary sample of 44 participants. The study used a Bayesian statistical approach to provide probabilistic expressions.

Results

The participants had an average work experience of 17 years, an average age of 38.6 years, an average weight of 81.48 kilograms, an average height of 176 centimeters, and an average of 2.5 qualifications. The results indicated that the firefighters performed external chest compressions with excellent technique and a moderate level of perceived effort in a two-minute evaluation. The evaluation of the evolution of the technique over time showed that the participants were able to maintain high-quality compressions for an average of 6 minutes, with a maximum of 20 uninterrupted minutes.

Conclusion

The study underscores the critical role of professional firefighters in performing and maintaining high-quality external chest compressions, which has the potential to reduce morbidity and mortality in cases of cardiorespiratory arrest.

The relationship between upper extremity functional performance and anthropometric features and the quality criteria of cardiopulmonary resuscitation

Objectives: This study aims to examine the effect of upper extremity performance using the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST) on cardiopulmonary resuscitation (CPR) quality criteria according to the European Resuscitation Council (ERC) Guidelines for Resuscitation 2015, including chest compression rate, depth, and recoil.

Patients and methods: This simulation-based study included 105 paramedic students (43 males, 62 females; median age: 19 years; range, 18 to 20 years) attending a two-year paramedic program between February 2018 and April 2018. The CKCUEST was used to determine upper extremity performance scores, including the touch number, normalized, and power score of the paramedic students. A TrueCPR® feedback device was used to measure CPR quality criteria throughout the study. The characteristics of the providers, such as height, weight, body mass index (BMI), and fat-free mass were also analyzed.

Results: Adequate compression depth had a positive correlation with body fat-free mass (r=0.397, p<0.001), power score (r=0.326, p=0.001), height (r=0.326, p=0.001), weight (r=0.314, p=0.001), and BMI (r=0.204, p=0.037). Full chest recoil had a negative correlation with the power score (r=-0.249, p=0.010) and height (r=-0.219, p=0.025). None of the variables were significantly different between the groups with and without the correct compression rate. In the receiver operating characteristic curve analysis for power score and correct compression depth as 100%, the area under the curve was 0.845 (p<0.001).

Conclusion: The power score combination of upper extremity functionality and the rescuer’s weight is the main factor affecting chest compression depth. However, this score is negatively correlated with full chest recoil.

Rescuers' characteristics associated with the correct chest compression during cardiopulmonary resuscitation

AIM

To analyse the caregivers' physical, anthropometrical and educational characteristics associated with adequate chest compression and full chest recoil during cardiopulmonary resuscitation (CPR).

METHODS

An observational prospective research study was conducted. Emergency and critical care health professionals and students performed two minutes of chest compressions on a dummy. Depth and residual leaning after the compressions were assessed and their association with several variables (physical, anthropometrical, and educational) was analysed using logistic regression models.

RESULTS

Two hundred thirty-eight volunteers participated. Previous experience of the rescuer in less than six CPRs (OR = 3.03; 95% CI 1.2-7.63) was related to a higher probability of not achieving an adequate depth of compressions. Greater height (OR: .93; 95% CI .87-.99) and grip strength (OR: .94; 95% CI .89-.99) were associated with correct performance of chest compression. We did not find any characteristic related to chest recoil.

CONCLUSIONS

The caregiver's previous experience with CPR was the strongest factor associated with adequate performance of chest compressions. To a lesser extent, the professional's height and upper body muscle strength also have an influence. No factors associated with the adequacy of full chest recoil were identified.

How effective are chest compressions when wearing mask? A randomised simulation study among first-year health care students during the COVID-19 pandemic

Background

The resuscitation guidelines provided for the COVID-19 pandemic strongly recommended wearing personal protective equipment. The current study aimed to evaluate and compare the effectiveness of chest compressions and the level of fatigue while wearing two different types of mask (surgical vs. cloth).

Methods

A randomized, non-inferiority, simulation study was conducted. Participants were randomised into two groups: surgical mask group (n = 108) and cloth mask group (n = 108). The effectiveness (depth and rate) of chest compressions was measured within a 2-min continuous chest-compression-only CPR session. Data were collected through an AMBU CPR Software, a questionnaire, recording vital parameters, and using Borg-scale related to fatigue (before and after the simulation). For further analysis the 2-min session was segmented into 30-s intervals.

Results

Two hundred sixteen first-year health care students participated in our study. No significant difference was measured between the surgical mask and cloth mask groups in chest compression depth (44.49 ± 10.03 mm vs. 45.77 ± 10.77 mm), rate (113.34 ± 17.76/min vs. 111.23 ± 17.51/min), and the level of fatigue (5.72 ± 1.69 vs. 5.56 ± 1.67) (p > 0.05 in every cases). Significant decrease was found in chest compression depth between the first 30-s interval and the second, third, and fourth intervals (p < 0.01).

Conclusion

The effectiveness of chest compressions (depth and rate) was non-inferior when wearing cloth mask compared to wearing surgical mask. However, the effectiveness of chest compressions decreased significantly in both groups during the 2-min chest-compression-only CPR session and did not reach the appropriate chest compression depth range recommended by the ERC.

The Relationship between Selected Body Composition Components and Cardiopulmonary Resuscitation Parameters in Nurses: An Observational Simulation Study

The provision of cardiopulmonary resuscitation (CPR) may be related to the physical parameters of the medical personnel, including fat mass (FM) and fat-free mass (FFM) components. In this study, we aimed to assess the relationship between selected body composition components and chest compression and ventilation parameters provided by medical staff. An observational simulation study was undertaken between December 2017 and January 2019 at the Center for Innovative Research in Medical and Natural Sciences of Rzeszów. In all participants (505 nurses, 37.71 y ± 12.16), the body weight and height were measured and the body mass index (BMI) was calculated. The body composition indicators were obtained using a bioelectrical impedance device, AKERN BIA 101. Afterwards, all participants performed CPR sequences (30 chest compressions and rescue for 2 breaths) for 2 min on a Laerdal Resusci Anne simulator placed on an examination couch with a self-inflating bag and a face mask. Our observations proved that high values of the anthropometric, nutritional and body composition parameters of the medical staff demonstrated a positive significant correlation with the depth and rate chest parameters and were inversely related to the chest adequate recoil. No statistically significant differences were found between the FM or FFM components and ventilation parameters. This study showed that nutritional status and body composition components may be important factors affecting the quality of CPR.

Dispatcher instructions for bystander cardiopulmonary resuscitation and neurologically intact survival after bystander-witnessed out-of-hospital cardiac arrests: a nationwide, population-based observational study

Background

The International Liaison Committee on Resuscitation recommends that dispatchers provide instructions to perform compression-only cardiopulmonary resuscitation (CPR) to callers responding to adults with out-of-hospital cardiac arrest (OHCA). This study aimed to determine the optimal dispatcher-assisted CPR (DA-CPR) instructions for OHCA.

Methods

We analysed the records of 24,947 adult patients (aged ≥ 18 years) who received bystander DA-CPR after bystander-witnessed OHCA. Data were obtained from a prospectively recorded Japanese nationwide Utstein-style database for a 2-year period (2016–2017). Patients were divided into compression-only DA-CPR (n = 22,778) and conventional DA-CPR (with a compression-to-ventilation ratio of 30:2, n = 2169) groups. The primary outcome measure was 1-month neurological intact survival, defined as a cerebral performance category score of 1–2 (CPC 1–2).

Results

The 1-month CPC 1–2 rate was significantly higher in the conventional DA-CPR group than in the compression-only DA-CPR group (before propensity score (PS) matching, 7.5% [162/2169] versus 5.8% [1309/22778], p < 0.01; after PS matching, 7.5% (162/2169) versus 5.7% (123/2169), p < 0.05). Compared with compression-only DA-CPR, conventional DA-CPR was associated with increased odds of 1-month CPC 1–2 (before PS matching, adjusted odds ratio 1.39, 95% confidence interval [CI] 1.14–1.70, p < 0.01; after PS matching, adjusted odds ratio 1.34, 95% CI 1.00–1.79, p < 0.05).

Conclusion

Within the limitations of this retrospective observational study, conventional DA-CPR with a compression-to-ventilation ratio of 30:2 was preferable to compression-only DA-CPR as an optimal DA-CPR instruction for coaching callers to perform bystander CPR for adult patients with bystander-witnessed OHCAs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03825-w.

Dispatcher-assisted conventional cardiopulmonary resuscitation and outcomes for paediatric out-of-hospital cardiac arrests

AIM

As asphyxial cardiac arrest is more common than cardiac arrest from a primary cardiac event in paediatric cardiac arrest, effective ventilation is important during paediatric cardiopulmonary resuscitation (CPR). We aimed to determine optimal dispatcher-assisted CPR instructions for bystanders after paediatric out-of-hospital cardiac arrest (OHCA).

METHODS

We analysed the records of 8172 children who received bystander dispatcher-assisted CPR. Data were obtained from an All-Japan Utstein-style registry from 2005 to 2017. Patients were divided into conventional CPR and compression-only CPR groups. The primary study endpoint was 1-month neurologically intact survival, defined as a Cerebral Performance Category score of 1 or 2 (CPC 1-2).

RESULTS

The 1-month CPC 1-2 rate was significantly higher in the dispatcher-assisted conventional CPR group than in the dispatcher-assisted compression-only CPR group (before propensity score matching, 5.7% [175/3077] vs. 3.1% [160/5095], p < 0.0001, adjusted odds ratio 2.48, 95% confidence interval 1.19-3.22; after propensity score matching, 6.0% [156/2618] vs. 2.6% [69/2618], p < 0.0001, adjusted odds ratio 2.42, 95% confidence interval 1.76-3.32). In most subgroup analyses after matching, dispatcher-assisted conventional CPR had a higher CPC 1-2 rate than dispatcher-assisted compression-only CPR; however, CPC 1-2 rates were similar between the two groups for patients with an initial shockable rhythm, those with total prehospital CPR time ≥ 20 min, those receiving public access defibrillation, advanced airway management, or adrenaline administration.

CONCLUSION

Within the limitations of this retrospective observational study, dispatcher-assisted conventional CPR was preferable to dispatcher-assisted compression-only CPR as optimal CPR instructions for coaching callers to perform bystander CPR.

Physical activity and quality of cardiopulmonary resuscitation: A secondary analysis of the MANI-CPR trial

INTRODUCTION

The association between the level of physical activity and quality of cardio-pulmonary resuscitation (CPR) performed by laypeople is unclear. The aim of this study was to evaluate the associations between physical activity level and laypeople performance during an eight-minute scenario of CPR.

MATERIALS AND METHODS

This study was a secondary analysis of the MANI-CPR Trial. The entire cohort of participants was grouped based on the level of physical activity assessed using the International Physical Activity Questionnaire (IPAQ) into a "low-moderate" level group and a "high" level group. Descriptive statistics were used for unadjusted analysis and multivariate logistic and linear regression models were also performed.

RESULTS

A total of 492 participants who reached the score of "Advanced CPR performer" at the 1-min final test monitored by Laerdal Resusci Anne QCPR were included in this analysis; 224 with a low-moderate level and 268 with a high level of physical activity. A statistically significant difference was found for the outcome of percentage of compressions with adequate depth (low-moderate group: 87.8% [41·4%-99·3%], high group: 97% [63·2%-100%]; P = 0·003). No associations remained significant after controlling for biometric characteristics of the participants, compression protocols and sex.

CONCLUSION

Adequate quality CPR may not need high baseline level of physical activity to be performed by a lay rescuer.

Rescuers' characteristics associated with the correct chest compression during cardiopulmonary resuscitation

AIM

To analyse the caregivers' physical, anthropometrical and educational characteristics associated with adequate chest compression and full chest recoil during cardiopulmonary resuscitation (CPR).

METHODS

An observational prospective research study was conducted. Emergency and critical care health professionals and students performed two minutes of chest compressions on a dummy. Depth and residual leaning after the compressions were assessed and their association with several variables (physical, anthropometrical, and educational) was analysed using logistic regression models.

RESULTS

Two hundred thirty-eight volunteers participated. Previous experience of the rescuer in less than six CPRs (OR: 3.03; CI 95%: 1.2-7.63) was related to a higher probability of not achieving an adequate depth of compressions. Greater height (OR: .93; 95% CI: .87-.99) and grip strength (OR: .94; 95% CI: .89-.99) were associated with correct performance of chest compression. We did not find any characteristic related to chest recoil.

CONCLUSIONS

The caregiver's previous experience with CPR was the strongest factor associated with adequate performance of chest compressions. To a lesser extent, the professional's height and upper body muscle strength also have an influence. No factors associated with the adequacy of full chest recoil were identified.

Deliberate practice in resuscitation training using a feedback device, and the effects of the physical characteristics of the rescuer on the acquisition and retention of cardiopulmonary resuscitation skills: Randomized clinical trial

BACKGROUND

Cardiopulmonary resuscitation (CPR) skills decline rapidly and rescuers' physical characteristics could impact on their performance. Our aim was to analyse the effects of deliberate practice using a feedback device (FD) on the CPR performance of nursing students prior to, immediately after, and three months after training, considering their physical characteristics.

METHOD

Sixty nursing students participated in this randomized clinical trial (control group n = 28; training group n = 32). Their physical characteristics (weight, height, forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)% index, handgrip strength, and CPR position strength) were measured before starting the trial. The training group followed a CPR training programme based on deliberate practice, providing feedback on their performance using an FD. All participants were evaluated during two-minute CPR compression/ventilation cycles.

RESULTS

The training group showed an improved ability to perform chest compressions (F_{(2, 115.2)} = 13.3; p < .001; ω²_p = 0.17) and ventilations (F_{(2, 115.3)} = 102.1; p < .001; ω²_p = 0.63), improving their overall quality of CPR (F_{(2, 115.2)} = 40.1; p < .001; ω²_p = 0.40). The physical characteristics of the participants did not affect CPR performance in any study phase.

CONCLUSIONS

A structured training programme based on deliberate practice using an FD had a positive effect on the acquisition of CPR skills by participants, while their physical characteristics had no impact on performance.

How Does Rescuer Fitness Affect the Quality of Prolonged Cardiopulmonary Resuscitation?

Objective: High quality cardiopulmonary resuscitation (CPR) is crucial for patients experiencing cardiac arrest. CPR quality declines within the first few minutes of CPR performance. Being more fit is associated with higher CPR quality, yet the fitness parameters needed remain uncertain. It is also unknown how CPR quality is affected during a protocol of realistic CPR when rescuers switch compressors every two minutes, as recommended by the American Heart Association (AHA), and extended duration, as might be encountered with an out-of-hospital cardiac arrest. The purpose of the present study is to determine the extent to which different measures of physical fitness predict high quality CPR performance when rescuers follow current CPR guidelines. Methods: Subjects underwent a fitness assessment evaluating lower back muscular endurance, abdominal muscular endurance, upper body muscular strength, and upper body anaerobic power. At least 48 hours later, subjects returned to the laboratory for CPR testing. CPR quality was determined by compression rate (>100/minute), compression depth (>2 inches, or 50 mm), and adequate (full) chest recoil between compressions, based on American Heart Association guidelines. A CPR Quality Score, designed to represent cardiac output, was calculated as the product of compression rate and depth. Results: Thirty-three of 42 subjects were able to achieve a CPR Quality Score greater than 5000, the minimum needed to meet AHA recommendations. Higher anaerobic power and bench press scores were predictive of both high CPR Quality Scores (R²=0.47) and compression depth (R²=0.47). Sex (female) was predictive of better chest compression recoil percentages (R²=0.15). Conclusion: Most rescuers can maintain high quality CPR if given two minute breaks between cycles. Rescuers with high anaerobic fitness and muscular strength may be able to provide higher quality CPR.

Caregiver Characteristics Associated With Quality of Cardiac Compressions on an Adult Mannequin With Real-Time Visual Feedback: A Simulation-Based Multicenter Study

INTRODUCTION

Chest compression (CC) quality directly impacts cardiac arrest outcomes. Provider body type can influence the quality of cardiopulmonary resuscitation (CPR); however, the magnitude of this impact while using visual feedback is not well described. The aim of the study was to determine the association between provider anthropometric variables on fatigue and CC adherence to 2015 American Heart Association CPR while receiving visual feedback.

METHODS

This was a planned secondary analysis of healthcare professionals from multiple hospitals performing continuous CC for 2 minutes on an adult CPR mannequin with dynamic visual feedback. Main outcome measures include compression data (depth, rate, and lean) evaluated in 30-second epochs to explore performance fatigue. Multivariable models examined the relationship of provider anthropometrics to CC quality. Binomial mixed effects models were used to characterize fatigue by examining performance for 4 epochs.

RESULTS

Three hundred seventy-seven 2-minute CC episodes were analyzed. Extreme (low and high) BMI and weight are associated with poorer CC. Larger size (height, weight, and BMI) is associated with better depth but worse lean compliance. Performance fatigued for all providers for 2 minutes, but shorter, lighter weight, female participants had the greatest decline. On multivariable analysis, rate compliance did not deteriorate regardless of provider anthropometrics.

CONCLUSIONS

Anthropometrics impact provider CC quality. Despite visual feedback, variable effects are seen on compression depth, rate, recoil, and fatigue depending on the provider sex, weight, and BMI. The 2-minute interval for changing chest compressors should be reconsidered based on individual provider characteristics and risk of fatigue's impact on high-quality CPR.

The feasibility of emergency medical technicians performing intermittent high-quality cardiopulmonary resuscitation

Background: Whether intermittent chest compressions have an effect on the quality of CPR is worthy of discussion. The purpose of this study was to investigate differences in the chest compression quality of emergency medical technicians (EMTs) performing cardiopulmonary resuscitation (CPR) with different rest intervals. Methods: Seventy male firefighters with EMT licenses participated in this study. Participants completed body composition measurements and three CPR quality tests, as follows: (1) CPR-uninterrupted for 10 minutes; (2) after 2 days of rest, CPR 10s-intermittent (CPR-10s), for 2 minutes each time and 5 cycles; (3) after another 2 days of rest, CPR 20s-intermittent (CPR-20s), for 2 minutes each time and 5 cycles. Results: Body composition results showed that body mass (BM), body mass index (BMI), upper limb muscle mass (ULMM), core muscle mass (CMM), and upper limb-core muscle mass (UL+CMM) were positively correlated with chest compression depth (CCD) (p < 0.05). Analysis of the three different modes of CPR quality analysis indicated significant differences in the chest compression fraction (CCF, F = 6.801, p = 0.001), chest compression rebound rate (CCRR, F = 3.919, p = 0.021), and ratings of perceived exertion (RPE, F = 23.815, p < 0.001). Among the different performance cycles of CPR-10s, significant differences were found in CCF, CCD, CCR (chest compression rate), and RPE (p < 0.05). On the other hand, among the different performance cycles of CPR-20s, significant differences were found in CCD, CCR, and RPE (p < 0.05). Moreover, the CCF, CCD, and RPE scores of the two tests reached significant differences in specific phases (p < 0.05). Conclusions: This study confirmed that the upper limb muscle mass or the weight of the upper body of EMTs is positively correlated with the quality of CPR. In addition, intermittent chest compressions with safe interruption intervals can reduce fatigue caused by long-term chest compressions and maintain better chest compression quality.

Impacto das superfícies de compressão na massagem cardíaca durante a reanimação cardiopulmonar: uma revisão integrativa

Resumo Objetivo sintetizar as evidências disponíveis na literatura sobre os tipos de superfícies de compressão utilizadas na RCP e analisar quais características das superfícies de compressão têm impacto na eficácia da compressão torácica durante a RCP. Método revisão integrativa da literatura, cujos critérios de seleção e inclusão foram: artigos completos, em inglês, português ou espanhol e que respondessem a seguinte questão de pesquisa: “Quais são as características das superfícies de compressão que têm impacto na eficácia das compressões torácicas durante a RCP?”. Realizada entre os meses de junho e julho de 2019. Resultados inclui-se 12 artigos de estudos experimentais, cuja extração de dados revelou 13 tipos diferentes de colchões. Em relação às pranchas, seis tamanhos diferentes foram relatados, com diferentes materiais. Constatou-se influências do tipo de superfície de compressão na força necessária para realizar as compressões torácicas. Conclusão as evidências apontam que colchões de maiores dimensões e com tecnologia para redução de pressão e camas mais largas apresentam impactos negativos na qualidade das compressões torácicas. Implicação para prática o conhecimento sobre a influência do tipo e características das superfícies de apoio na qualidade das compressões torácicas podem subsidiar profissionais na escolha e incorporação de tecnologias no ambiente hospitalar.

Influence of Physical Activity of the Rescuer on Chest Compression Duration and its Effects on Hemodynamics and Fatigue Levels of the Rescuer: A Simulation-based Study

Background

Cardiopulmonary resuscitation (CPR) is a lifesaving skill performed during the cardiac arrest. Various factors of rescuer affect CPR quality, and rescuers physical fitness is one among the important factors needs to be explored for improved CPR quality. This study aimed to assess the physical activity (PA) levels of the health care providers (HCPs) who were trained in basic life support (BLS) and its relationship on chest compression duration, hemodynamic parameters, and fatigue levels of the rescuers.

Materials and methods

A single-center, cross-sectional study was conducted on 48 HCPs who were trained in BLS within one year. Eligible participants were contacted by email, and the responders’ level of PA was determined using the global physical activity questionnaire (GPAQ). The participants were recruited for chest compression-only cardiac arrest scenarios. Each subject performed continuous chest compression on the manikin until they perceived maximum fatigue. Heart rate (HR), blood pressure (BP), oxygen saturation (SpO₂), and fatigue level were assessed at baseline, immediately after and following two minutes of cessation of chest compressions. The total duration of chest compression was also documented.

Results

Most participants (24, 50%) reported high levels of PA while 22 (45.83%) and 2 (4.17%) reported moderate and low intensity of PA, respectively. The mean age of the 35 participants was 26.08 ± 4.60 years. The mean duration of chest compressions was 193.25 seconds with higher times reported for those with high PA when compared to those with moderate PA (p = 0.017). Similar findings were also observed for fatigue.

Conclusion

Rescuers who reported high PA had lower levels of fatigue and could perform longer duration of chest compressions.

How to cite this article

Nayak VR, Babu A, Unnikrishnan R, Babu AS, Krishna HM. Influence of Physical Activity of the Rescuer on Chest Compression Duration and its Effects on Hemodynamics and Fatigue Levels of the Rescuer: a Simulation-based Study. Indian J Crit Care Med 2020;24(6):409–413.

Wearing a N95 mask increases rescuer's fatigue and decreases chest compression quality in simulated cardiopulmonary resuscitation

Objectives

N95 mask is essential for healthcare workers dealing with the coronavirus disease 2019 (COVID-19). However, N95 mask causes discomfort breathing with marked reduction in air exchange. This study was designed to investigate whether the use of N95 mask affects rescuer's fatigue and chest compression quality during cardiopulmonary resuscitation (CPR).

Methods

After a brief review of CPR, each participant performed a 2-minute continuous chest compression on a manikin wearing N95 (N95 group, n = 40) or surgical mask (SM group, n = 40). Compression rate and depth, the proportions of correct compression rate, depth, complete chest recoil and hand position were documented. Participants' fatigue was assessed using Borg score.

Results

Significantly lower mean chest compression rate and depth were both achieved in the N95 group than in the SM group (p < 0.05, respectively). In addition, the proportion of correct compression rate (61 ± 19 vs. 75 ± 195, p = 0.0067), depth (67 ± 16 vs. 90 ± 14, p < 0.0001) and complete recoil (91 ± 16 vs. 98 ± 5%, p = 0.0248) were significantly decreased in the N95 group as compared to the SM group. At the end of compression, the Borg score in the N95 group was significantly higher than that in the SM group (p = 0.027).

Conclusion

Wearing a N95 mask increases rescuer's fatigue and decreases chest compression quality during CPR. Therefore, the exchange of rescuers during CPR should be more frequent than that recommended in current guidelines when N95 masks are applied.

Differences in the performance of resuscitation according to the resuscitation guideline terminology during infant cardiopulmonary resuscitation: "Approximately 4 cm" versus "at least one-third the anterior-posterior diameter of the chest"

Aim

This study was conducted to investigate the effect of resuscitation guideline terminology on the performance of infant cardiopulmonary resuscitation (CPR).

Methods

A total of 40 intern or resident physicians conducted 2-min CPR with the two-finger technique (TFT) and two-thumb technique (TT) on a simulated infant cardiac arrest model with a 1-day interval. They were randomly assigned to Group A or B. The participants of Group A conducted CPR with the chest compression depth (CCD) target of “approximately 4 cm” and those of Group B conducted CPR with the CCD target of “at least one-third the anterior-posterior diameter of the chest”. Single rescuer CPR was performed with a 15:2 compression to ventilation ratio on the floor.

Results

In both chest compression techniques, the average CCD of Group B was significantly deeper than that of Group A (TFT: 41.0 [range, 39.3–42.0] mm vs. 36.5 [34.0–37.9] mm, P = 0.002; TT: 42.0 [42.0–43.0] mm vs. 37.0 [35.3–38.0] mm, P < 0.001). Adequacy of CCD also showed similar results (Group B vs. A; TFT: 99% [82–100%] vs. 29% [12–58%], P = 0.001; TT: 100% [100–100%] vs. 28% [8–53%], P < 0.001).

Conclusions

Using the CCD target of “at least one-third the anterior-posterior diameter of the chest” resulted in deep and adequate chest compressions during simulated infant CPR in contrast to the CCD target of “approximately 4 cm”. Therefore, changes in the terminology used in the guidelines should be considered to improve the quality of CPR.

Trial registration

Clinical Research Information Service; cris.nih.go.kr/cris/en (Registration number: KCT0003486).

Interventions to improve the quality of bystander cardiopulmonary resuscitation: A systematic review

Background

Performing high-quality bystander cardiopulmonary resuscitation (CPR) improves the clinical outcomes of victims with sudden cardiac arrest. Thus far, no systematic review has been performed to identify interventions associated with improved bystander CPR quality.

Methods

We searched Ovid MEDLINE, Ovid EMBASE, EBSCO CINAHL, Ovid PsycInfo, Thomson Reuters SCI-EXPANDED, and the Cochrane Central Register of Controlled Trials to retrieve studies published from 1 January 1966 to 5 October 2018 associated with interventions that could improve the quality of bystander CPR. Data regarding participant characteristics, interventions, and design and outcomes of included studies were extracted.

Results

Of the initially identified 2,703 studies, 42 were included. Of these, 32 were randomized controlled trials. Participants included adults, high school students, and university students with non-medical professional majors. Interventions improving bystander CPR quality included telephone dispatcher-assisted CPR (DA-CPR) with simplified or more concrete instructions, compression-only CPR, and other on-scene interventions, such as four-hand CPR for elderly rescuers, kneel on opposite sides for two-person CPR, and CPR with heels for a tired rescuer. Devices providing real-time feedback and mobile devices containing CPR applications or software were also found to be beneficial in improving the quality of bystander CPR. However, using mobile devices for improving CPR quality or for assisting DA-CPR might cause rescuers to delay starting CPR.

Conclusions

To further improve the clinical outcomes of victims with cardiac arrest, these effective interventions may be included in the guidelines for bystander CPR.

Morbid obesity impairs adequacy of thoracic compressions in a simulation-based model

Adequate cardiopulmonary resuscitation is an important predictor of survival, however, obesity provides a significant physical barrier to thoracic compressions. This study explores the effect of morbid obesity on compression adequacy. We performed a prospective randomised controlled crossover study, assessing the adequacy of thoracic compressions on a manikin modified to emulate a morbidly obese patient. Participants recruited from critical care departments were randomised to perform continuous compressions for two minutes on each manikin. Accelerometers were used to measure thoracic wall movement. The primary endpoint was a composite measure of compression adequacy (rate, depth and recoil). Secondary endpoints were the individual components of the composite outcome and measures of perceived effectiveness, fatigue, and pain. One hundred and one participants were recruited. There was a significant difference between the obese and control groups in the composite endpoint (4% versus 30%, <i>P</i> <0.001), as well as the individual components of adequacy (<i>P</i> <0.01 for all). Quartile data showed significant deterioration in adequacy of depth and recoil in both groups, and this occurred significantly earlier in the obese group (<i>P</i> ≤0.001). Participants' perception of effectiveness was significantly lower (<i>P</i> ≤0.001) in the obese group, and levels of fatigue (<i>P</i> ≤0.001) and pain (<i>P</i> ≤0.001) significantly higher. Morbid obesity impairs the adequacy of thoracic compressions for trained rescuers in a simulation-based model. Participants were not fully aware of how ineffective compressions were. There is evidence of earlier fatigue further reducing effectiveness. These findings have significant implications for the training of rescuers in a clinically relevant population and the planning of future research.

Children saving lives: Training towards CPR excellence levels in chest compression based on age and physical characteristics

BACKGROUND

The World Health Organization's endorsement of the "Kids save lives" statement fosters the implementation of cardiopulmonary resuscitation (CPR) training for school children worldwide. However, not every child achieves and maintains the recommended chest compression depth of 5-6cm.

PURPOSE

To investigate the variability in compression depth for three age groups (grade 1: 12-14; grade 2: 14-16; grade 3: 16-18 years) as a function of physical characteristics and to define minimal compression excellence levels for training.

METHODS

Compression depth of 265 subjects (111 girls, 154 boys) aged 12-18 years from one secondary school was individually assessed and reported in percentiles per age group. Pearson correlations between physical characteristics and CPR variables were calculated. Excellence level was defined as the percentage compressions with depth 5-6cm.

RESULTS

In grade 1 (12-14 years), achieved excellence levels were 1% for girls and 23% for boys at the 75th percentile. In grade 2 (14-16 years), it increased to 24% for girls and 80% for boys. In grade 3 (16-18 years) finally, it was 59% for girls and 87% for boys. Significant positive correlations were found between CPR and physical variables (p<0.05), especially weight >50kg (p<0.01).

CONCLUSION

A minimal excellence level of 25% is achievable by boys 12-14year and girls 14-16year and can be gradually improved to 60% and 90% according to age and gender. This might necessitate more exertion and training for some younger children, especially girls, and will probably be more easily achieved for children weighing >50kg.

Relationship between chest compression depth and novice rescuer body weight during cardiopulmonary resuscitation

OBJECTIVE

This study determined if rescuer body weight is a major determinant of chest compression depth (CCD) among novice rescuers by analyzing the results of cardiopulmonary resuscitation (CPR) skill tests among medical students and determined the body weight threshold for those unable to achieve adequate CCD.

METHODS

Retrospective analysis of CPR test results was performed. A total of 107 medical students completed the tests, which included 5 cycles of CPR. Data were collected using a ResusciAnne SkillReporter. Anthropometric data including participant body weight, body mass index, and height were also collected. The relationships between CCD and anthropometric data were evaluated by Pearson correlation coefficient. In addition, univariate linear regression analysis was used to assess the association between body weight and CCD.

RESULTS

The highest positive correlation was found between CCD and body weight (r = 0.636, P < .001). Body weight correlated with CCD by as much as 40.5% (R² = 40.5, P < .001). Using a regression model, we described the association between body weight and CCD as follows: expected CCD (mm) = 0.46 × body weight + 17.59. The regression equation shows that rescuers weighing more than 70.5 kg could achieve a CCD of 50 mm.

CONCLUSIONS

Rescuer body weight is a major determinant of CCD in novice rescuers. Based on these findings, if 2 or more rescuers are available to perform CPR, chest compression should preferentially be performed by rescuers of healthy weight or overweight.