Rescuer fatigue: standard versus continuous chest-compression cardiopulmonary resuscitation

Design and Evaluation of CPR Emergency Equipment for Non-Professionals

Sudden cardiac death is a sudden and highly fatal condition. Implementing high-quality emergency cardiopulmonary resuscitation (CPR) early on is an effective rescue method for this disease. However, the rescue steps of CPR are complicated and difficult to remember, and the quantitative indicators are difficult to control, which leads to a poor quality of CPR emergency actions outside the hospital setting. Therefore, we have developed CPR emergency equipment with a multisensory feedback function, aiming to guide rescuers in performing CPR through visual, auditory, and tactile interaction. This equipment consists of three components: first aid clothing, an audio-visual integrated terminal, and a vital sign detector. These three components are based on a micro-power WiFi-Mesh network, enabling the long-term wireless transmission of the multisensor data. To evaluate the impact of the multisensory feedback CPR emergency equipment on nonprofessionals, we conducted a controlled experiment involving 32 nonmedical subjects. Each subject was assigned to either the experimental group, which used the equipment, or the control group, which did not. The main evaluation criteria were the chest compression (CC) depth, the CC rate, the precise depth of the CC ratio (5-6 cm), and the precise rate of the CC ratio -(100-120 times/min). The results indicated that the average CC depth in the experimental group was 51.5 ± 1.3 mm, which was significantly better than that of the control group (50.2 ± 2.2 mm, p = 0.012). Moreover, the average CC rate in the experimental group (110.1 ± 6.2 times/min) was significantly higher than that of the control group (100.4 ± 6.6 times/min) (p < 0.001). Compared to the control group (66.37%), the experimental group showed a higher proportion of precise CC depth (82.11%), which is closer to the standard CPR rate of 100%. In addition, the CC ratio of the precise rate was 93.75% in the experimental group, which was significantly better than that of 56.52% in the control group (p = 0.024). Following the experiment, the revised System Availability Scale (SUS) was utilized to evaluate the equipment's usability. The average total SUS score was 78.594, indicating that the equipment's acceptability range was evaluated as 'acceptable', and the overall adjective rating was 'good'. In conclusion, the multisensory feedback CPR emergency equipment significantly enhances the CC performance (CC depth, CC rate, the precise depth of CC ratio, the precise rate of CC ratio) of nonprofessionals during CPR, and the majority of participants perceive the equipment as being easy to use.

Temporal analysis of continuous chest compression rate and depth performed by firefighters during out of hospital cardiac arrest

BACKGROUND

Quality of chest compressions (CC) during cardiopulmonary resuscitation (CPR) often do not meet guideline recommendations for rate and depth. This may be due to the fatiguing nature of physically compressing a patient's chest, meaning that CPR quality reduces over time.

OBJECTIVE

This analysis investigates the effect of CPR duration on the performance of continuous CCs delivered by firefighters equipped with CPR feedback devices.

METHODS

Data were collected from a first responder group which used CPR feedback and automatic external defibrillator devices when attending out-of-hospital cardiac arrest events. Depth and rate of CC were analysed for 134 patients. Mean CC depth and rate were calculated every 5 s during two-minute episodes of CPR. Regression models were created to evaluate the relationship between applied CC depth and rate as a function of time.

RESULTS

Mean (SD) CC depth during the investigation was 48 (9) mm. An inverse relationship was observed between CC depth and CPR duration, where CC depth decreased by 3.39 mm, over two-minutes of CPR (p < 0.001). Mean (SD) CC rate was 112.06 (5.87) compressions per minute. No significant relationship was observed between CC rate and CPR duration (p = 0.077). Mean depth was within guideline range for 33.58% of patient events, while guideline rate was observed in 92.54% of cases.

CONCLUSIONS

A reduction in CC depth was observed during two-minutes of continuous CCs while CC rate was not affected. One third of patients received a mean CC depth within guideline range (50 to 60 mm).

Chest compression quality during CPR of potential contagious patients wearing personal protection equipment

AIM OF THE STUDY

In this study we aimed to investigate whether changing rescuers wearing N95 masks every 1 min instead of the standard CPR change over time of 2 min would make a difference in effective chest compressions.

METHODS

This study was a randomized controlled mannequin study. Participants were selected from healthcare staff. They were divided into two groups of two people in each group. The scenario was implemented on CPR mannequin representing patient with asystolic arrest, that measured compression depth, compression rate, recoil, and correct hand position. Two different scenarios were prepared. In Scenario 1, the rescuers were asked to change chest compression after 1 min. In Scenario 2, standard CPR was applied. The participants' vital parameters, mean compression rate, correct compression rate/ratio, total number of compressions, compression depth, correct recoil/ratio, correct hand position/ratio, mean no-flow time, and total CPR time were recorded.

RESULTS

The study hence included 14 teams each for scenarios, with a total of 56 participants. In each scenario, 14 participants were physicians and 14 participants were women. Although there was no difference in the first minute of the cycles starting from the fourth cycle, a statistically significant difference was observed in the second minute in all cycles except the fifth cycle.

CONCLUSION

Changing the rescuer every 1 min instead of every 2 min while performing CPR with full PPE may prevent the decrease in compression quality that may occur as the resuscitation time gets longer.

Provider Fatigue During Direct Manual Compression for Life-Threatening Bleeding

Introduction

Trauma is a leading cause of death throughout the world, with hemorrhage being responsible for more than 35% of pre-hospital trauma deaths and more than 40% of deaths within the first 24 hours after injury. Despite first aid having a demonstrable effect on mortality from trauma, relatively little research has compared the best methods for bleeding control in the prehospital first aid setting. The most common first-line therapy for external bleeding control in the pre-hospital first aid setting is direct manual compression (DMC). However, a prior study demonstrated that the primary cause of failure in a simulated model of life-threatening bleeding was the inability to maintain adequate direct pressure for three minutes. In this study, we evaluated the effect of fatigue on DMC for the duration of a typical urban emergency medical services (EMS) response time.

Methods

We conducted a prospective observational trial of 33 participants, 18 years of age or older to measure the pressure generated on a model of life-threatening bleeding over an eight-minute period using a “CPR posture” for applying pressure. The primary analyses were longitudinal two-level multilevel models (MLM) with repeated measures of outcome (i.e., CPR posture pressure) nesting within participants. The demographic factors of gender, age, and weight were included as moderators in the analyses and each was analyzed independently.

Results

The participants’ average age was 31 (SD = 11) and the average weight was 161 pounds (SD = 31). The sample consisted of 18 female participants (54.5%) and 15 male participants (45.5%). Applied DMC pressure declined over time, more sharply initially from the beginning to approximately 250 seconds, at which point the decrease in pressure was gradual. Of the demographic factors, gender was associated with a difference in cardiopulmonary resuscitation (CPR) posture pressure over time.

Conclusion

Rescuers should be aware that fatigue may occur and may affect the quality of direct manual compression for control of life-threatening bleeding. Further research is needed to define the external pressures needed to control life-threatening bleeding and the extent that rescuer fatigue affects this pressure.

Efficacy of cardiopulmonary resuscitation performance while wearing a powered air-purifying respirator

BACKGROUND

The use of personal protective equipment for respiratory infection control during cardiopulmonary resuscitation (CPR) is a physical burden to healthcare providers. The duration for which CPR quality according to recommended guidelines can be maintained under these circumstances is important. We investigated whether a 2-min shift was appropriate for chest compression and determined the duration for which chest compression was maintained in accordance with the recommended guidelines while wearing personal protective equipment.

METHODS

This prospective crossover simulation study was performed at a single center from September 2020 to October 2020. Five indicators of CPR quality were measured during the first and second sessions of the study period. All participants wore a Level D powered air-purifying respirator (PAPR), and the experiment was conducted using a Resusci Anne manikin, which can measure the quality of chest compressions. Each participant conducted two sessions. In Session 1, the sequence of 2 min of chest compressions, followed by a 2-min rest, was repeated twice; in Session 2, the sequence of 1-min chest compressions followed by a 1-min rest was repeated four times.

RESULTS

All 34 participants completed the study. The sufficiently deep compression rate was 65.9 ± 31.1% in the 1-min shift group and 61.5 ± 30.5% in the 2-min shift group. The mean compression depth was 52.8 ± 4.3 mm in the 1-min shift group and 51.0 ± 6.1 mm in the 2-min shift group. These two parameters were significantly different between the two groups. There was no significant difference in the other values related to CPR quality.

CONCLUSIONS

Our findings indicated that 1 min of chest compressions with a 1-min rest maintained a better quality of CPR while wearing a PAPR.

Adaptations to Protect Sideline Providers as They Respond to Sudden Cardiac Arrest During Sars-CoV-2

ABSTRACT

The 2019 severe acute respiratory syndrome coronavirus 2 has dramatically changed the sports landscape, compelling sports medical providers to adapt to evolving scientific discoveries and adopt ever-changing guidelines that protect our athletes, ourselves, and our staff. To best serve our athletes, providers need to be proactive and anticipate potential complications in providing care for athletes as athletic events resume.

Chest compression release and recoil dynamics in prolonged manual cardiopulmonary resuscitation

AIM OF THE STUDY

Characterize release and recoil dynamics in chest compressions during prolonged cardiopulmonary resuscitation (CPR) efforts, which are increasingly prevalent.

METHODS

Force and depth of chest compressions, and their rates of change, were calculated from records extracted from CPR monitors used during prolonged resuscitation efforts for out-of-hospital cardiac arrest and tracked over time. Metrics were normalized to the median of the first 100 compressions. Kruskal-Wallis ANOVA and Jonckheere-Terpstra trend analyses were used for differences and trends. Averages are reported as median (interquartile range). Correlations among metrics are reported as coefficients of determination.

RESULTS

In 471 cases of adult subjects receiving at least 1000 compressions, peak depths varied modestly over the course of extended resuscitation efforts, staying within a narrow range without a trend over the course of resuscitation efforts. Increases in recoil velocity and decreases in recoil interval also remained within limited ranges (5%, 6% variation respectively). By contrast, force waveforms changed substantially. Peak force decreased monotonically reaching a 38% decrease for compression numbers > 3500, similar to a decrease in release rate (39%) and an increase in release interval (39%).

CONCLUSION

Depth waveforms change markedly less than do force waveforms over the course of prolonged CPR. With the benefit of feedback, CPR providers effectively adjust the application of force to compensate for changes in chest stiffness, documented previously. Despite slowing release and quickening recoil, interference between release of force and recoil of depth appears limited. Spontaneous chest recoil is well preserved in prolonged duration manual CPR.

Evaluation of the effect of shift cycle time on chest compression quality during cardiopulmonary resuscitation

Objective

Considering the potential role of shift cycle time on chest compression quality during cardiopulmonary resuscitation (CPR) and the available contradictory results in this regard, the present study aimed at evaluating the effect of 1-min versus 2-min shift cycle time on the quality of CPR.

Materials and Methods

In this randomized crossover study, 80 rescuers performed CPR on a manikin in two scenarios with a rotation of 1 and 2-min cycles. The quality of CPR was evaluated and compared based on the information obtained regarding the chest compression depth, recoil, and rate of chest compression. In addition, rescuer fatigue was recorded in 1-min versus 2-min shift cycles.

Results

In the 1-min group, the number of chest compressions per minute, complete recoil, and good rate with the mean of 114.89 ± 3.62, 54.34 ± 3.86, and 76.06 ± 8.00 were significantly higher than those of the 2-min group with the mean of 113.78 ± 4.94, 53.49 ± 5.27, and 73.98 ± 7.87 (P < 0.05), respectively. In addition, the quality of CPR provided by males was significantly higher than females in both groups. The score of rescuer fatigue was higher in the 2-min group as compared with the 1-min group (P < 0.001).

Conclusion

According to the results of the present study, the difference in the quality of CPR in terms of the number of chest compressions, complete recoil, and good rate was higher in the 1-min group as compared with the 2-min group. In addition, the quality of CPR in terms of chest compression depth and number in both 1-and 2-min rotation cycles was higher for male rescuers than females. Furthermore, rescuer fatigue was higher in the 2-min group as compared with the 1-min group. The mentioned finding may be a factor in reducing, albeit slightly, the quality of CPR in the group with a longer time.

A Multicenter International Randomized Controlled Manikin Study on Different Protocols of Cardiopulmonary Resuscitation for Laypeople: The MANI-CPR Trial

BACKGROUND

Compression-only cardiopulmonary resuscitation (CPR) is a suggested technique for laypeople facing out-of-hospital cardiac arrest (OHCA). However, it is difficult performing high-quality CPR until emergency medical services arrival with this technique. We aimed to verify whether incorporating intentional interruptions of different frequency and duration increases laypeople's CPR quality during an 8-minute scenario compared with compression-only CPR.

METHODS

We performed a multicenter randomized manikin study selecting participants from 2154 consecutive laypeople who followed a basic life support/automatic external defibrillation course. People who achieved high-quality CPR in 1-minute test on a computerized manikin were asked to participate. Five hundred seventy-six were enrolled, and 59 were later excluded for technical reasons or incorrect test recording. Participants were randomized in an 8-minute OHCA scenario using 3 CPR protocols (30 compressions and 2-second pause, 30c2s; 50 compressions and 5-second pause, 50c5s; 100 compressions and 10-second pause, 100c10s) or compression-only technique. The main outcome was the percentage of chest compressions with adequate depth.

RESULTS

Five hundred seventeen participants were evaluated. There was a statistically significant difference regarding the percentage of compressions with correct depth among the groups (30c2s, 96%; 50c5s, 96%; 100c10s, 92%; compression only, 79%; P = 0.006). Post hoc comparison showed a significant difference for 30c2s (P = 0.023) and for 50c5s (P = 0.003) versus compression only. Regarding secondary outcome, there were a higher chest compression fraction in the compression-only group and a higher rate of pauses longer than 10 seconds in the 100c10s.

CONCLUSIONS

In a simulated OHCA, 30c2s and 50c5s protocols were characterized by a higher rate of chest compressions with correct depth than compression only. This could have practical consequences in laypeople CPR training and recommendations.Clinical Trial Registration: NCT02632500.

Cardiopulmonary Resuscitation With Mechanical Chest Compression Device During Percutaneous Coronary Intervention. A Case Report

Sudden cardiac death is a leading cause of death worldwide, whereby myocardial infarction is considered the most frequent underlying condition. Percutaneous coronary intervention (PCI) is an important component of post-resuscitation care, while uninterrupted high-quality chest compressions are key determinants in cardiopulmonary resuscitation (CPR). In our paper, we evaluate a case of a female patient who suffered aborted cardiac arrest due to myocardial infarction. The ambulance crew providing prehospital care for sudden cardiac arrest used a mechanical chest compression device during advanced CPR, which enabled them to deliver ongoing resuscitation during transfer to the PCI laboratory located 20 km away from the scene. Mechanical chest compressions were continued during the primary coronary intervention. The resuscitation, carried out for 2 h and 35 min, and the coronary intervention were successful, as evidenced by the return of spontaneous circulation and by the fact that, after a short rehabilitation, the patient was discharged home with a favorable neurological outcome. Our case can serve as an example for the effective and safe use of a mechanical compression device during primary coronary intervention.

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.

Change in Cardiopulmonary Resuscitation Performance Over Time During Simulated Pediatric Cardiac Arrest and the Effect of Just-in-Time Training and Feedback

OBJECTIVES

Effective cardiopulmonary resuscitation (CPR) is critical to ensure optimal outcomes from cardiac arrest, yet trained health care providers consistently struggle to provide guideline-compliant CPR. Rescuer fatigue can impact chest compression (CC) quality during a cardiac arrest event, although it is unknown if visual feedback or just-in-time training influences change of CC quality over time. In this study, we attempt to describe the changes in CC quality over a 12-minute simulated resuscitation and examine the influence of just-in-time training and visual feedback on CC quality over time.

METHODS

We conducted secondary analysis of data collected from the CPRCARES study, a multicenter randomized trial in which CPR-certified health care providers from 10 different pediatric tertiary care centers were randomized to receive visual feedback, just-in-time CPR training, or no intervention. They participated in a simulated cardiac arrest scenario with 2 team members providing CCs. We compared the quality of CCs delivered (depth and rate) at the beginning (0-4 minutes), middle (4-8 minutes), and end (8-12 minutes) of the resuscitation.

RESULTS

There was no significant change in depth over the 3 time intervals in any of the arms. There was a significant increase in rate (128 to 133 CC/min) in the no intervention arm over the scenario duration (P < 0.05).

CONCLUSIONS

There was no significant drop in CC depth over a 12-minute cardiac arrest scenario with 2 team members providing compressions.

Comparison of Long-Term Effects between Chest Compression-Only CPR Training and Conventional CPR Training on CPR Skills among Police Officers

Despite of the changes of out-of-hospital cardiac arrest (OHCA) survival rise when bystander CPR is provided, this was only conducted in about 23% of OHCA patients in Korea in 2018. Police officers acting as first responders have a high chance of witnessing situations requiring CPR. We investigated long-term effects on CPR quality between chest compression-only CPR training and conventional CPR training in police officers to find an efficient CPR training method in a prospective, randomized, controlled trial. Police officers underwent randomization and received different CPR training. With the Brayden Pro application, we compared the accuracy of CPR skills immediately after training and the one after 3 months. Right after training, the conventional CPR group presented the accuracy of the CPR skills (compression rate: 74.6%, compression depth: 66.0%, recoil: 78.0%, compression position: 96.1%) and chest compression-only CPR group presented the accuracy of the CPR skills (compression rate: 74.5%, compression depth: 71.6%, recoil: 79.2%, compression position: 99.0%). Overall, both groups showed the good quality of CPR skills and had no meaningful difference right after the training. However, three months after training, overall accuracy of CPR skills decreased, a significant difference between two groups was observed for compression position (conventional CPR: 80.0%, chest compression only CPR: 95.0%). In multiple linear regression analysis, three months after CPR training, chest compression-only CPR training made CPR skills accuracy 28.5% higher. In conclusion, police officers showed good-quality CPR right after CPR training in both groups. But three months later, chest compression-only CPR training group had better retention of CPR skills. Therefore, chest compression-only CPR training is better to be a standard training method for police officers as first responders.

Adult Basic Life Support: International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This 2020 International Consensus on Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care Science With Treatment Recommendations on basic life support summarizes evidence evaluations performed for 20 topics that were prioritized by the Basic Life Support Task Force of the International Liaison Committee on Resuscitation. The evidence reviews include 16 systematic reviews, 3 scoping reviews, and 1 evidence update. Per agreement within the International Liaison Committee on Resuscitation, new or revised treatment recommendations were only made after a systematic review.

Systematic reviews were performed for the following topics: dispatch diagnosis of cardiac arrest, use of a firm surface for CPR, sequence for starting CPR (compressions-airway-breaths versus airway-breaths-compressions), CPR before calling for help, duration of CPR cycles, hand position during compressions, rhythm check timing, feedback for CPR quality, alternative techniques, public access automated external defibrillator programs, analysis of rhythm during chest compressions, CPR before defibrillation, removal of foreign-body airway obstruction, resuscitation care for suspected opioid-associated emergencies, drowning, and harm from CPR to victims not in cardiac arrest.

The topics that resulted in the most extensive task force discussions included CPR during transport, CPR before calling for help, resuscitation care for suspected opioid-associated emergencies, feedback for CPR quality, and analysis of rhythm during chest compressions. After discussion of the scoping reviews and the evidence update, the task force prioritized several topics for new systematic reviews.

Adult Basic Life Support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This2020 International Consensus on Cardiopulmonary Resuscitation(CPR)and Emergency Cardiovascular Care Science With Treatment Recommendationson basic life support summarizes evidence evaluations performed for 22 topics that were prioritized by the Basic Life Support Task Force of the International Liaison Committee on Resuscitation. The evidence reviews include 16 systematic reviews, 5 scoping reviews, and 1 evidence update. Per agreement within the International Liaison Committee on Resuscitation, new or revised treatment recommendations were only made after a systematic review.

Systematic reviews were performed for the following topics: dispatch diagnosis of cardiac arrest, use of a firm surface for CPR, sequence for starting CPR (compressions-airway-breaths versus airway-breaths-compressions), CPR before calling for help, duration of CPR cycles, hand position during compressions, rhythm check timing, feedback for CPR quality, alternative techniques, public access automated external defibrillator programs, analysis of rhythm during chest compressions, CPR before defibrillation, removal of foreign-body airway obstruction, resuscitation care for suspected opioid-associated emergencies, drowning, and harm from CPR to victims not in cardiac arrest.

The topics that resulted in the most extensive task force discussions included CPR during transport, CPR before calling for help, resuscitation care for suspected opioid-associated emergencies, feedback for CPR quality, and analysis of rhythm during chest compressions. After discussion of the scoping reviews and the evidence update, the task force prioritized several topics for new systematic reviews.

Resuscitation of the patient with suspected/confirmed COVID-19 when wearing personal protective equipment: A randomized multicenter crossover simulation trial

BACKGROUND

The aim of the study was to evaluate various methods of chest compressions in patients with suspected/confirmed SARS-CoV-2 infection conducted by medical students wearing full personal protective equipment (PPE) for aerosol generating procedures (AGP).

METHODS

This was prospective, randomized, multicenter, single-blinded, crossover simulation trial. Thirty-five medical students after an advanced cardiovascular life support course, which included performing 2-min continuous chest compression scenarios using three methods: (A) manual chest compression (CC), (B) compression with CPRMeter, (C) compression with LifeLine ARM device. During resuscitation they are wearing full personal protective equipment for aerosol generating procedures.

RESULTS

The median chest compression depth using manual CC, CPRMeter and LifeLine ARM varied and amounted to 40 (38-45) vs. 45 (40-50) vs. 51 (50-52) mm, respectively (p = 0.002). The median chest compression rate was 109 (IQR; 102-131) compressions per minute (CPM) for manual CC, 107 (105-127) CPM for CPRMeter, and 102 (101-102) CPM for LifeLine ARM (p = 0.027). The percentage of correct chest recoil was the highest for LifeLine ARM - 100% (95-100), 80% (60-90) in CPRMeter group, and the lowest for manual CC - 29% (26-48).

CONCLUSIONS

According to the results of this simulation trial, automated chest compression devices (ACCD) should be used for chest compression of patients with suspected/confirmed COVID-19. In the absence of ACCD, it seems reasonable to change the cardiopulmonary resuscitation algorithm (in the context of patients with suspected/confirmed COVID-19) by reducing the duration of the cardiopulmonary resuscitation cycle from the current 2-min to 1-min cycles due to a statistically significant reduction in the quality of chest compressions among rescuers wearing PPE AGP.

Providing the best chest compression quality: Standard CPR versus chest compressions only in a bystander resuscitation model

AIM OF THE STUDY

Bystander-initiated basic life support (BLS) for the treatment of prehospital cardiac arrest increases survival but is frequently not performed due to fear and a lack of knowledge. A simple flowchart can improve motivation and the quality of performance. Furthermore, guidelines do recommend a chest compression (CC)-only algorithm for dispatcher-assisted bystander resuscitation, which may lead to increased fatigue and a loss of compression depth. Consequently, we wanted to test the hypothesis that CCs are more correctly delivered in a flowchart-assisted standard resuscitation algorithm than in a CC-only algorithm.

METHODS

With the use of a manikin model, 84 laypersons were randomized to perform either flowchart-assisted standard resuscitation or CC-only resuscitation for 5min. The primary outcome was the total number of CCs.

RESULTS

The total number of correct CCs did not significantly differ between the CC-only group and the standard group (63 [±81] vs. 79 [±86]; p = 0.394; 95% CI of difference: 21-53). The total hand-off time was significantly lower in the CC-only group than in the standard BLS group. The relative number of correct CCs (the fraction of the total number of CCs achieving 5-6cm) and the level of exhaustion after BLS did not significantly differ between the groups.

CONCLUSION

Standard BLS did not lead to an increase in correctly delivered CCs compared to CC-only resuscitation and exhibited significantly more hand-off time. The low rate of CCs in both groups indicates the need for an increased focus on performance during BLS training.

Paramedic equipment bags: How their position during out-of-hospital cardiopulmonary resuscitation (CPR) affect paramedic ergonomics and performance

This study investigates how the positions of paramedic equipment bags affect paramedic performance and biomechanical loads during out-of-hospital Cardiopulmonary Resuscitation (CPR). An experiment was conducted in which 12 paramedic teams (each including two paramedics) performed in-situ simulations of a cardiac-arrest scenario. CPR quality was evaluated using five standard resuscitation measures (i.e., pre- and post-shock pauses, and compression rate, depth and fraction). The spinal loads while lifting, pulling and pushing the equipment bags were assessed using digital human modeling software (Jack) and prediction equation from previous studies. The results highlight where paramedics are currently choosing to position their equipment. They also demonstrate that the positions of the equipment bags affect CPR quality as well as the paramedics' work efficiency, physiological effort and biomechanical loads. The spinal loads ranged from 1901 to 4030N; furthermore, every occasion on which an equipment bag was lifted resulted in spinal forces higher than 3400N, thus exceeding the maximum threshold stipulated by the National Institute for Occupational Safety and Health. 72% of paramedics' postures were categorized as high or very high risk for musculoskeletal disorders by the Rapid Entire Body Assessment. Guidelines related to bag positioning and equipment handling might improve CPR quality and patient outcomes, and reduce paramedics' risk of injury.

Electrophysiology of Muscle Fatigue in Cardiopulmonary Resuscitation on Manikin Model

Cardiopulmonary resuscitation requires the provider to adopt positions that could be dangerous for his or her spine, specifically affecting the muscles and ligaments in the lumbar zone and the scapular spinal muscles. Increased fatigue caused by muscular activity during the resuscitation could produce a loss of quality and efficacy, resulting in compromising resuscitation. The aim of this study was to evaluate the maximum time a rescuer can perform uninterrupted chest compressions correctly without muscle fatigue. This pilot study was performed at Universidad Complutense de Madrid (Spain) with the population recruited following CONSORT 2010 guidelines. From the 25 volunteers, a total of 14 students were excluded because of kyphoscoliosis (4), lumbar muscle pain (1), anti-inflammatory treatment (3), or not reaching 80% of effective chest compressions during the test (6). Muscle activity at the high spinal and lumbar (L5) muscles was assessed using electromyography while students performed continuous chest compressions on a ResusciAnne manikin. The data from force exerted were analyzed according to side and muscle groups using Student's t test for paired samples. The influence of time, muscle group, and side was analyzed by multivariate analyses ( p ≤ .05). At 2 minutes, high spinal muscle activity (right: 50.82 ± 9.95; left: 57.27 ± 20.85 μV/ms) reached the highest values. Activity decreased at 5 and 15 minutes. At 2 minutes, L5 activity (right: 45.82 ± 9.09; left: 48.91 ± 10.02 μV/ms) reached the highest values. After 5 minutes and at 15 minutes, activity decreased. Fatigue occurred bilaterally and time was the most important factor. Fatigue began at 2 minutes. Rescuers exert muscular countervailing forces in order to maintain effective compressions. This imbalance of forces could determine the onset of poor posture, musculoskeletal pain, and long-term injuries in the rescuer.

Singapore Paediatric Resuscitation Guidelines 2016

We present the revised 2016 Singapore paediatric resuscitation guidelines. The International Liaison Committee on Resuscitation's Pediatric Taskforce Consensus Statements on Science and Treatment Recommendations, as well as the updated resuscitation guidelines from the American Heart Association and European Resuscitation Council released in October 2015, were debated and discussed by the workgroup. The final recommendations for the Singapore Paediatric Resuscitation Guidelines 2016 were derived after carefully reviewing the current available evidence in the literature and balancing it with local clinical practice.

Addition of Audiovisual Feedback During Standard Compressions Is Associated with Improved Ability

Introduction

A benefit of in-hospital cardiac arrest is the opportunity for rapid initiation of “high-quality” chest compressions as defined by current American Heart Association (AHA) adult guidelines as a depth 2–2.4 inches, full chest recoil, rate 100–120 per minute, and minimal interruptions with a chest compression fraction (CCF) ≥ 60%. The goal of this study was to assess the effect of audiovisual feedback on the ability to maintain high-quality chest compressions as per 2015 updated guidelines.

Methods

Ninety-eight participants were randomized into four groups. Participants were randomly assigned to perform chest compressions with or without use of audiovisual feedback (+/− AVF). Participants were further assigned to perform either standard compressions with a ventilation ratio of 30:2 to simulate cardiopulmonary resuscitation (CPR) without an advanced airway or continuous chest compressions to simulate CPR with an advanced airway. The primary outcome measured was ability to maintain high-quality chest compressions as defined by current 2015 AHA guidelines.

Results

Overall comparisons between continuous and standard chest compressions (n=98) were without significant differences in chest compression dynamics (p’s >0.05). Overall comparisons between +/− AVF (n = 98) were significant for differences in average rate of compressions per minute (p= 0.0241) and proportion of chest compressions within guideline rate recommendations (p = 0.0084). There was a significant difference in the proportion of high quality-chest compressions favoring AVF (p = 0.0399). Comparisons between chest compression strategy groups +/− AVF were significant for differences in compression dynamics favoring AVF (p’s < 0.05).

Conclusion

Overall, AVF is associated with greater ability to maintain high-quality chest compressions per most-recent AHA guidelines. Specifically, AVF was associated with a greater proportion of compressions within ideal rate with standard chest compressions while demonstrating a greater proportion of compressions with simultaneous ideal rate and depth with a continuous compression strategy.

Clinical outcome of canine cardiopulmonary resuscitation following the RECOVER clinical guidelines at a Japanese nighttime animal hospital

A set of evidence-based consensus guidelines for cardiopulmonary resuscitation (CPR) in dogs and cats (RECOVER guidelines) was published in 2012. The purpose of this study was to investigate the clinical outcomes of CPR performed according to those guidelines in dogs. A total of 141 dogs with cardiopulmonary arrest (CPA) were identified and underwent CPR between January 2012 and December 2015 at the Sapporo Nighttime Animal Hospital. CPR was performed according to no-consensus traditional veterinary CPR procedures in 68 dogs (TRADITIONAL group), and according to the RECOVER guidelines in 73 dogs (RECOVER group). There was no significant difference in the age, body weight, or time from CPA identification to initiation of CPR between the TRADITIONAL and RECOVER groups (median [range]: 10 [0–16] vs. 11 [0–16] years; 6.6 [1.0–58.6] vs. 5.5 [1.1–30.4] kg; and 0 [0–30] vs. 0 [0–30] min, respectively). In the TRADITIONAL group, 12 dogs (17%) achieved a return of spontaneous circulation (ROSC), but none survived to hospital discharge. However, 32 dogs (43%) in the RECOVER group achieved ROSC, and 4 dogs (5%) were discharged from the hospital. Incorporating the RECOVER guidelines into clinical practice significantly improved the ROSC rate (P<0.001). However, the rate of survival to hospital discharge was still low. This may suggest that a superior intensive care unit that provides advanced post-CPA care could benefit veterinary CPR patients.

Easy-to-learn cardiopulmonary resuscitation training programme: a randomised controlled trial on laypeople's resuscitation performance

INTRODUCTION

Simplifying the learning of cardiopulmonary resuscitation (CPR) is advocated to improve skill acquisition and retention. A simplified CPR training programme focusing on continuous chest compression, with a simple landmark tracing technique, was introduced to laypeople. The study aimed to examine the effectiveness of the simplified CPR training in improving lay rescuers' CPR performance as compared to standard CPR.

METHODS

A total of 85 laypeople (aged 21-60 years) were recruited and randomly assigned to undertake either a two-hour simplified or standard CPR training session. They were tested two months after the training on a simulated cardiac arrest scenario. Participants' performance on the sequence of CPR steps was observed and evaluated using a validated CPR algorithm checklist. The quality of chest compression and ventilation was assessed from the recording manikins.

RESULTS

The simplified CPR group performed significantly better on the CPR algorithm when compared to the standard CPR group (p < 0.01). No significant difference was found between the groups in time taken to initiate CPR. However, a significantly higher number of compressions and proportion of adequate compressions was demonstrated by the simplified group than the standard group (p < 0.01). Hands-off time was significantly shorter in the simplified CPR group than in the standard CPR group (p < 0.001).

CONCLUSION

Simplifying the learning of CPR by focusing on continuous chest compressions, with simple hand placement for chest compression, could lead to better acquisition and retention of CPR algorithms, and better quality of chest compressions than standard CPR.

Team Size and Stretching-Exercise Effects on Simulated Chest Compression Performance and Exertion

Introduction

Investigators conducted a prospective experimental study to evaluate the effect of team size and recovery exercises on individual providers’ compression quality and exertion. Investigators hypothesized that 1) larger teams would perform higher quality compressions with less exertion per provider when compared to smaller teams; and 2) brief stretching and breathing exercises during rest periods would sustain compressor performance and mitigate fatigue.

Methods

In Phase I, a volunteer cohort of pre-clinical medical students performed four minutes of continuous compressions on a Resusci-Anne manikin to gauge the spectrum of compressor performance in the subject population. Compression rate, depth, and chest recoil were measured. In Phase II, the highest-performing Phase I subjects were placed into 2-, 3-, and/or 4-compressor teams; 2-compressor teams were assigned either to control group (no recovery exercises) or intervention group (recovery exercises during rest). All Phase II teams participated in 20-minute simulations with compressor rotation every two minutes. Investigators recorded compression quality and real-time heart rate data, and calculated caloric expenditure from contact heart rate monitor measurements using validated physiologic formulas.

Results

Phase I subjects delivered compressions that were 24.9% (IQR1–3: [0.5%–74.1%]) correct with a median rate of 112.0 (IQR1–3: [103.5–124.9]) compressions per minute and depth of 47.2 (IQR1–3: [35.7–55.2]) mm. In their first rotations, all Phase II subjects delivered compressions of similar quality and correctness (p=0.09). Bivariate analyses of 2-, 3-, and 4-compressor teams’ subject compression characteristics by subsequent rotation did not identify significant differences within or across teams. On multivariate analyses, only subjects in 2-compressor teams exhibited significantly lower compression rates (control subjects; p<0.01), diminished chest release (intervention subjects; p=0.03), and greater exertion over successive rotations (both control [p≤0.03] and intervention [p≤0.02] subjects).

Conclusion

During simulated resuscitations, 2-compressor teams exhibited increased levels of exertion relative to 3- and 4-compressor teams for comparable compression delivery. Stretching and breathing exercises intended to assist with compressor recovery exhibited mixed effects on compression performance and subject exertion.

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.

Investigation of low back and shoulder demand during cardiopulmonary resuscitation

Limited research has examined the effect of different compression-ventilation ratios on the ergonomic demand of performing cardiopulmonary resuscitation (CPR) over time. This study aimed to compare the biomechanical demand of performing continuous chest compression CPR (CCC-CPR) and standard CPR (30:2 compression to breath ratio). Fifteen CPR certified individuals performed both standard CPR and CCC-CPR, randomly assigned, for three 2-min periods. Trunk and upper limb muscle activation, lumbar spine posture and compression force applied to a testing mannequin chest were measured throughout each CPR trial. No differences in muscle activation of spine posture were observed, however chest compression force decreased over the two minutes (p < 0.0001). Further, this drop in force was larger and initiated immediately during the CCC-CPR trials. This immediate drop in force during the CCC-CPR trials may be an anticipatory adjustment in order to be able to sustain continuous compressions for the full 2 min duration.

Morrison L. Automated Data Abstraction of Cardiopulmonary Resuscitation Process Measures for Complete Episodes of Cardiac Arrest Resuscitation

BACKGROUND

Cardiopulmonary resuscitation (CPR) process measures research and quality assurance has traditionally been limited to the first 5 minutes of resuscitation due to significant costs in time, resources, and personnel from manual data abstraction. CPR performance may change over time during prolonged resuscitations, which represents a significant knowledge gap. Moreover, currently available commercial software output of CPR process measures are difficult to analyze.

OBJECTIVE

The objective was to develop and validate a software program to help automate the abstraction and transfer of CPR process measures data from electronic defibrillators for complete episodes of cardiac arrest resuscitation.

METHODS

We developed a software program to facilitate and help automate CPR data abstraction and transfer from electronic defibrillators for entire resuscitation episodes. Using an intermediary Extensible Markup Language export file, the automated software transfers CPR process measures data (electrocardiogram [ECG] number, CPR start time, number of ventilations, number of chest compressions, compression rate per minute, compression depth per minute, compression fraction, and end-tidal CO₂ per minute). We performed an internal validation of the software program on 50 randomly selected cardiac arrest cases with resuscitation durations between 15 and 60 minutes. CPR process measures were manually abstracted and transferred independently by two trained data abstractors and by the automated software program, followed by manual interpretation of raw ECG tracings, treatment interventions, and patient events. Error rates and the time needed for data abstraction, transfer, and interpretation were measured for both manual and automated methods, compared to an additional independent reviewer.

RESULTS

A total of 9,826 data points were each abstracted by the two abstractors and by the software program. Manual data abstraction resulted in a total of six errors (0.06%) compared to zero errors by the software program. The mean ± SD time measured per case for manual data abstraction was 20.3 ± 2.7 minutes compared to 5.3 ± 1.4 minutes using the software program (p = 0.003).

CONCLUSIONS

We developed and validated an automated software program that efficiently abstracts and transfers CPR process measures data from electronic defibrillators for complete cardiac arrest episodes. This software will enable future cardiac arrest studies and quality assurance programs to evaluate the impact of CPR process measures during prolonged resuscitations.

Differences in Hands-off Time According to the Position of a Second Rescuer When Switching Compression in Pre-hospital Cardiopulmonary Resuscitation Provided by Two Bystanders: A Randomized, Controlled, Parallel Study

The change of compressing personnel will inevitably accompany hands off time when cardiopulmonary resuscitation (CPR) is performed by two or more rescuers. The present study assessed whether changing compression by a second rescuer located on the opposite side (OS) of the first rescuer can reduce hands-off time compared to CPR on the same side (SS) when CPR is performed by two rescuers. The scenario of this randomized, controlled, parallel simulation study was compression-only CPR by two laypersons in a pre-hospital situation. Considering sex ratio, 64 participants were matched up in 32 teams equally divided into two gender groups, i.e. , homogenous or heterogeneous. Each team was finally allocated to one of two study groups according to the position of changing compression (SS or OS). Every team performed chest compression for 8 min and 10 sec, with chest compression changed every 2 min. The primary endpoint was cumulative hands-off time. Cumulative hands-off time of the SS group was about 2 sec longer than the OS group, and was significant (6.6 ± 2.6 sec vs. 4.5 ± 1.5 sec, P = 0.005). The range of hands off time of the SS group was wider than for the OS group. The mean hands-off times of each rescuer turn significantly shortened with increasing number of turns (P = 0.005). A subgroup analysis in which cumulative hands-off time was divided into three subgroups in 5-sec intervals revealed that about 70% of the SS group was included in subgroups with delayed hands-off time ≥ 5 sec, with only 25% of the OS group included in these subgroups (P = 0.033). Changing compression at the OS of each rescuer reduced hands-off time compared to the SS in prehospital hands-only CPR provided by two bystanders.

Doubling survival and improving clinical outcomes using a left ventricular assist device instead of chest compressions for resuscitation after prolonged cardiac arrest: a large animal study

Introduction

Despite improvements in pre-hospital and post-arrest critical care, sudden cardiac arrest (CA) remains one of the leading causes of death. Improving circulation during cardiopulmonary resuscitation (CPR) may improve survival rates and long-term clinical outcomes after CA.

Methods

In a porcine model, we compared standard CPR (sCPR; n =10) with CPR using an intravascular cardiac assist device without additional chest compressions (iCPR; n =10) following 10 minutes of electrically induced ventricular fibrillation (VF). In a separate crossover experiment, 10 additional pigs were subjected to 10 minutes of VF and 6 minutes of sCPR; the iCPR device was then implanted if a return of spontaneous circulation (ROSC) was not achieved using sCPR. Animals were evaluated in respect to intra- and post-arrest hemodynamics, survival, functional outcome and cerebral and myocardial lesions following CPR. We hypothesized that iCPR would result in more frequent ROSC and better functional recovery than sCPR.

Results

iCPR produced a mean flow of 1.36 ± 0.02 L/min, leading to significantly higher coronary perfusion pressure (CPP) values during the early period of CPR (22 ± 10 mmHg vs. 9 ± 5 mmHg, P ≤0.01, 1 minute after start of CPR; 20 ± 11 mmHg vs. 10 ± 7 mmHg, P =0.03, 2 minutes after start of CPR), resulting in high ROSC rates (100% in iCPR vs. 50% in sCPR animals; P =0.03). iCPR animals showed significantly lower serum S100 levels at 10 and 30 minutes following ROSC (3.5 ± 0.6 ng/ml vs. 7.4 ± 3.0 ng/ml 30 minutes after ROSC; P ≤0.01), as well as superior clinical outcomes based on overall performance categories (2.9 ± 1.0 vs. 4.6 ± 0.8 on day 1; P ≤0.01). In crossover experiments, 80% of animals required treatment with iCPR after failed sCPR. Notably, ROSC was still achieved in six of the remaining eight animals (75%) after a total of 22.8 ± 5.1 minutes of ischemia.

Conclusions

In a model of prolonged cardiac arrest, the use of iCPR instead of sCPR improved CPP and doubled ROSC rates, translating into improved clinical outcomes.

Individualized rescuer change by a team leader during uninterrupted cardiopulmonary resuscitation: comparison with rescuer change in 2-min intervals

OBJECTIVE

Currently recommended cardiopulmonary resuscitation (CPR) guidelines to change rescuers in 2-min intervals do not consider the differences in the physical capability of individual rescuers. We compared the quality of chest compressions between the conventional rescuer rotation method (RC2, rescuers changed in 2-min intervals) and the novel rescuer rotation method (RCL, rescuers changed by a team leader's decision on the basis of gross assessment of the quality of chest compression).

METHODS

Ninety-six rescuers (48 pairs) were recruited and the sequence of the two-rescuer change methods (RC2 and RCL) was randomized. Forty-eight teams performed 8 min of uninterrupted two-rescuer CPR on a manikin with Skill-Reporter during two consecutive days (one method for each day).

RESULTS

The RCL method achieved deeper compression depth (mm) (52.6±3.8 vs. 49.5±4.7, P=0.002) and a higher number of correct chest compressions per minute (96.3±41.2 vs. 77.6±52.7, P<0.0001) than the RC2 method. However, the RCL method showed a longer total interruption time (s) than the RC2 method (21.1±3.9 vs. 14.8±1.0, P<0.0001) during 8 min of uninterrupted CPR.

CONCLUSION

The quality of chest compression was better with RCL than the conventional RC2 method in terms of compression depth and proportions of correct compressions. RCL may be a practical alternative rescuer change strategy during uninterrupted chest compressions, especially when objective parameters to monitor the quality of chest compression are not readily available.

Evaluation of Chest Compression Depth during Nine Minutes of Hands-Only Cardiopulmonary Resuscitation Performed by a Lone Rescuer and its Effect by Age Group: A Pilot Simulation Study Using a Manikin

Objective

There have been few studies on the use of long-standing hands-only cardiopulmonary resuscitation (CPR) by a lone rescuer. This study aimed to evaluate the long-standing (nine minutes) hands-only CPR by a lone rescuer, and the change of chest compression depth over time. The effect of age of rescuer on chest compression depth was also studied.

Methods

From a total of 404 adult lay-persons who participated in CPR training, 91 subjects were enrolled in the simulation trial of nine minutes of hands-only CPR using a manikin with a Skill-Reporter™. The quality of the chest compression over time and the effects of rescuer age were analysed.

Results

Of the 91 participants, 74 (81%) fully completed the nine minutes of CPR. No significant differences of incomplete CPR rate between each age group were observed. No significant differences in the degree of reduction in effective chest compressions were observed based on the time course among the different age groups. The total number of compressions decreased abruptly from the six-minute time point onwards (five minutes vs. six minutes, p=0.038).

Conclusions

Most trained lay-persons could complete the 9 minutes of hands-only CPR. The rate of chest compression shows a significant decrease after 6 minute. We do not find a significant difference in the decrease of adequate chest compressions over time among various age groups in this pilot simulation study.

Comparison of the quality of basic life support provided by rescuers trained using the 2005 or 2010 ERC guidelines

INTRODUCTION

Effective delivery of cardiopulmonary resuscitation (CPR) and prompt defibrillation following sudden cardiac arrest (SCA) is vital. Updated guidelines for adult basic life support (BLS) were published in 2010 by the European Resuscitation Council (ERC) in an effort to improve survival following SCA. There has been little assessment of the ability of rescuers to meet the standards outlined within these new guidelines.

METHODS

We conducted a retrospective analysis of the performance of first year healthcare students trained and assessed using either the new 2010 ERC guidelines or their 2005 predecessor, within the University of Birmingham, United Kingdom. All students were trained as lay rescuers during a standardised eight hour ERC-accredited adult BLS course.

RESULTS

We analysed the examination records of 1091 students. Of these, 561 were trained and assessed using the old 2005 ERC guidelines and 530 using the new 2010 guidelines. A significantly greater proportion of candidates failed in the new guideline group (16.04% vs. 11.05%; p < 0.05), reflecting a significantly greater proportion of lay-rescuers performing chest compressions at too fast a rate when trained and assessed with the 2010 rather than 2005 guidelines (6.04% vs. 2.67%; p < 0.05). Error rates for other skills did not differ between guideline groups.

CONCLUSIONS

The new ERC guidelines lead to a greater proportion of lay rescuers performing chest compressions at an erroneously fast rate and may therefore worsen BLS efficacy. Additional study is required in order to define the clinical impact of compressions performed to a greater depth and at too fast a rate.

Decay in chest compression quality due to fatigue is rare during prolonged advanced life support in a manikin model

BACKGROUND

The aim of this study was to measure chest compression decay during simulated advanced life support (ALS) in a cardiac arrest manikin model.

METHODS

19 paramedic teams, each consisting of three paramedics, performed ALS for 12 minutes with the same paramedic providing all chest compressions. The patient was a resuscitation manikin found in ventricular fibrillation (VF). The first shock terminated the VF and the patient remained in pulseless electrical activity (PEA) throughout the scenario. Average chest compression depth and rate was measured each minute for 12 minutes and divided into three groups based on chest compression quality; good (compression depth ≥ 40 mm, compression rate 100-120/minute for each minute of CPR), bad (initial compression depth < 40 mm, initial compression rate < 100 or > 120/minute) or decay (change from good to bad during the 12 minutes). Changes in no-flow ratio (NFR, defined as the time without chest compressions divided by the total time of the ALS scenario) over time was also measured.

RESULTS

Based on compression depth, 5 (26%), 9 (47%) and 5 (26%) were good, bad and with decay, respectively. Only one paramedic experienced decay within the first two minutes. Based on compression rate, 6 (32%), 6 (32%) and 7 (37%) were good, bad and with decay, respectively. NFR was 22% in both the 1-3 and 4-6 minute periods, respectively, but decreased to 14% in the 7-9 minute period (P = 0.002) and to 10% in the 10-12 minute period (P < 0.001).

CONCLUSIONS

In this simulated cardiac arrest manikin study, only half of the providers achieved guideline recommended compression depth during prolonged ALS. Large inter-individual differences in chest compression quality were already present from the initiation of CPR. Chest compression decay and thereby fatigue within the first two minutes was rare.

Manual versus mechanical cardiopulmonary resuscitation. An experimental study in pigs

BACKGROUND

Optimal manual closed chest compressions are difficult to give. A mechanical compression/decompression device, named LUCAS, is programmed to give compression according to the latest international guidelines (2005) for cardiopulmonary resuscitation (CPR). The aim of the present study was to compare manual CPR with LUCAS-CPR.

METHODS

30 kg pigs were anesthetized and intubated. After a base-line period and five minutes of ventricular fibrillation, manual CPR (n = 8) or LUCAS-CPR (n = 8) was started and run for 20 minutes. Professional paramedics gave manual chest compression's alternating in 2-minute periods. Ventilation, one breath for each 10 compressions, was given to all animals. Defibrillation and, if needed, adrenaline were given to obtain a return of spontaneous circulation (ROSC).

RESULTS

The mean coronary perfusion pressure was significantly (p < 0.01) higher in the mechanical group, around 20 mmHg, compared to around 5 mmHg in the manual group. In the manual group 54 rib fractures occurred compared to 33 in the LUCAS group (p < 0.01). In the manual group one severe liver injury and one pressure pneumothorax were also seen. All 8 pigs in the mechanical group achieved ROSC, as compared with 3 pigs in the manual group.

CONCLUSIONS

LUCAS-CPR gave significantly higher coronary perfusion pressure and significantly fewer rib fractures than manual CPR in this porcine model.

Rescuer fatigue during actual in-hospital cardiopulmonary resuscitation with audiovisual feedback: a prospective multicenter study

BACKGROUND

Rescuer fatigue during cardiopulmonary resuscitation (CPR) is a likely contributor to variable CPR quality during clinical resuscitation efforts, yet investigations into fatigue and CPR quality degradation have only been performed in simulated environments, with widely conflicting results.

OBJECTIVE

We sought to characterize CPR quality decay during actual in-hospital cardiac arrest, with regard to both chest compression (CC) rate and depth during the delivery of CCs by individual rescuers over time.

METHODS

Using CPR recording technology to objectively quantify CCs and provide audiovisual feedback, we prospectively collected CPR performance data from arrest events in two hospitals. We identified continuous CPR "blocks" from individual rescuers, assessing CC rate and depth over time.

RESULTS

135 blocks of continuous CPR were identified from 42 cardiac arrests at the two institutions. Median duration of continuous CPR blocks was 112s (IQR 101-122). CC rate did not change significantly over single rescuer performance, with an initial mean rate of 105+/-11/min, and a mean rate after 3 min of 106+/-9/min (p=NS). However, CC depth decayed significantly between 90s and 2 min, falling from a mean of 48.3+/-9.6mm to 46.0+/-9.0mm (p=0.0006) and to 43.7+/-7.4mm by 3 min (p=0.002).

CONCLUSIONS

During actual in-hospital CPR with audiovisual feedback, CC depth decay became evident after 90s of CPR, but CC rate did not change. These data provide clinical evidence for rescuer fatigue during actual resuscitations and support current guideline recommendations to rotate rescuers during CC delivery.

Comparison of 15:1, 15:2, and 30:2 compression-to-ventilation ratios for cardiopulmonary resuscitation in a canine model of a simulated, witnessed cardiac arrest

OBJECTIVES

This experimental study compared the effect of compression-to-ventilation (CV) ratios of 15:1, 15:2, and 30:2 on hemodynamics and resuscitation outcome in a canine model of a simulated, witnessed ventricular fibrillation (VF) cardiac arrest.

METHODS

Thirty healthy dogs, irrespective of species (mean +/- SD, 19.2 +/- 2.2 kg), were used in this study. A VF arrest was induced. The dogs received cardiopulmonary resuscitation (CPR) and were divided into three groups based on the applied CV ratios of 15:1, 15:2, and 30:2. After 1 minute of untreated VF, 4 minutes of basic life support (BLS) was performed. At the end of the 4 minutes, the dogs were defibrillated with an automatic external defibrillator (AED) and advanced cardiac life support (ACLS) efforts were continued for 10 minutes or until restoration of spontaneous circulation (ROSC) was attained, whichever came first.

RESULTS

None of the hemodynamic parameters, and arterial oxygen profiles was significantly different between the three groups during BLS- and ACLS-CPR. Eight dogs (80%) from each group achieved ROSC during BLS and ACLS. The survival rate was not different between the three groups. In the 15:1 and 30:2 groups, the number of compressions delivered over 1 minute were significantly greater than in the 15:2 group (73.1 +/- 8.1 and 69.0 +/- 6.9 to 56.3 +/- 6.8; p < 0.01). The time for ventilation during which compressions were stopped at each minute was significantly lower in the 15:1 and 30:2 groups than in the 15:2 group (15.4 +/- 3.9 and 17.1 +/- 2.7 to 25.2 +/- 2.6 sec/min; p < 0.01).

CONCLUSIONS

In a canine model of witnessed VF using a simulated scenario, CPR with three CV ratios, 15:1, 15:2, and 30:2, did not result in any differences in hemodynamics, arterial oxygen profiles, and resuscitation outcome among the three groups. CPR with a CV ratio of 15:1 provided comparable chest compressions and shorter pauses for ventilation between each cycle compared to a CV ratio of 30:2.