Performer fatigue and CPR quality comparing 30:2 to 15:2 compression to ventilation ratios in older bystanders: A randomized crossover trial

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.

Quality of chest compressions during pediatric resuscitation with 15:2 and 30:2 compressions-to-ventilation ratio in a simulated scenario

The main objetive was to compare 30:2 and 15:2 compression-to-ventilation ratio in two simulated pediatric cardiopulmonary resuscitation (CPR) models with single rescuer. The secondary aim was to analyze the errors or omissions made during resuscitation. A prospective randomized parallel controlled study comparing 15:2 and 30:2 ratio in two manikins (child and infant) was developed. The CPR was performed by volunteers who completed an basic CPR course. Each subject did 4 CPR sessions of 3 minutes each one. Depth and rate of chest compressions (CC) during resuscitation were measured using a Zoll Z series defibrillator. Visual assessment of resuscitation was performed by an external researcher. A total of 26 volunteers performed 104 CPR sessions. Between 54–62% and 44–53% of CC were performed with an optimal rate and depth, respectively, with no significant differences. No differences were found in depth or rate of CC between 15:2 and 30:2 compression-to-ventilation ratio with both manikins. In the assessment of compliance with the ERC CPR algorithm, 69.2–80.8% of the subjects made some errors or omissions during resuscitation, the most frequent was not asking for help and not giving rescue breaths. The conclusions were that a high percentage of CC were not performed with optimal depth and rate. Errors or omissions were frequently made by rescuers during resuscitation.

Bystander fatigue and CPR quality by older bystanders: a randomized crossover trial comparing continuous chest compressions and 30:2 compressions to ventilations

Objectives

This study sought to measure bystander fatigue and cardiopulmonary resuscitation (CPR) quality after five minutes of CPR using the continuous chest compression (CCC) versus the 30:2 chest compression to ventilation method in older lay persons, a population most likely to perform CPR on cardiac arrest victims.

Methods

This randomized crossover trial took place at three tertiary care hospitals and a seniors’ center. Participants were aged ≥55 years without significant physical limitations (frailty score ≤3/7). They completed two 5-minute CPR sessions (using 30:2 and CCC) on manikins; sessions were separated by a rest period. We used concealed block randomization to determine CPR method order. Metronome feedback maintained a compression rate of 100/minute. We measured heart rate (HR), mean arterial pressure (MAP), and Borg Exertion Scale. CPR quality measures included total number of compressions and number of adequate compressions (depth ≥5 cm).

Results

Sixty-three participants were enrolled: mean age 70.8 years, female 66.7%, past CPR training 60.3%. Bystander fatigue was similar between CPR methods: mean difference in HR -0.59 (95% CI −3.51-2.33), MAP 1.64 (95% CI −0.23-3.50), and Borg 0.46 (95% CI 0.07-0.84). Compared to 30:2, participants using CCC performed more chest compressions (480.0 v. 376.3, mean difference 107.7; p<0.0001) and more adequate chest compressions (381.5 v. 324.9, mean difference. 62.0; p=0.0001), although good compressions/minute declined significantly faster with the CCC method (p=0.0002).

Conclusions

CPR quality decreased significantly faster when performing CCC compared to 30:2. However, performing CCC produced more adequate compressions overall with a similar level of fatigue compared to the 30:2 method.

Chest compression quality, exercise intensity, and energy expenditure during cardiopulmonary resuscitation using compression-to-ventilation ratios of 15:1 or 30:2 or chest compression only: a randomized, crossover manikin study

OBJECTIVE

Our aim was to compare the compression quality, exercise intensity, and energy expenditure in 5-minute single-rescuer cardiopulmonary resuscitation (CPR) using 15:1 or 30:2 compression-to-ventilation (C:V) ratios or chest compression only (CCO).

METHODS

This was a randomized, crossover manikin study. Medical students were randomized to perform either type of CPR and do the others with intervals of at least 1 day. We measured compression quality, ratings of perceived exertion (RPE) score, heart rate, maximal oxygen uptake, and energy expenditure during CPR.

RESULTS

Forty-seven students were recruited. Mean compression rates did not differ between the 3 groups. However, the mean percentage of adequate compressions in the CCO group was significantly lower than that of the 15:1 or 30:2 group (31.2±30.3% vs. 55.1±37.5% vs. 54.0±36.9%, respectively; P<0.001) and the difference occurred within the first minute. The RPE score in each minute and heart rate change in the CCO group was significantly higher than those of the C:V ratio groups. There was no significant difference in maximal oxygen uptake between the 3 groups. Energy expenditure in the CCO group was relatively lower than that of the 2 C:V ratio groups.

CONCLUSION

CPR using a 15:1 C:V ratio may provide a compression quality and exercise intensity comparable to those obtained using a 30:2 C:V ratio. An earlier decrease in compression quality and increase in RPE and heart rate could be produced by CCO CPR compared with 15:1 or 30:2 C:V ratios with relatively lower oxygen uptake and energy expenditure.

Effect of bed width on the quality of compressions in simulated resuscitation: a randomized crossover manikin study

OBJECTIVES

To investigate the effects of bed width on the quality of chest compressions during simulated in-hospital resuscitation.

METHODS

Each candidate performed two 2-minute cycles of compression-only cardiopulmonary resuscitation on an adult manikin placed on either an emergency stretcher (narrow bed) or a standard hospital bed (wide bed) in random order at 1 day intervals. We conducted subjective assessments of cardiopulmonary resuscitation quality and rescuer fatigue at the end of each session, using surveys.

RESULTS

There were no significant differences between narrow and wide bed sessions in either mean depth or the percentage of compressions with adequate depth (P=.56 and .58, respectively). The mean rate of compressions and the percentage of compressions with adequate rate were also similar between sessions (P=.24 and .27, respectively). However, the percentage of correct hand position and complete chest recoil was significantly higher in the narrow bed session than in the wide bed session (P=.02 and .02, respectively). In addition, survey results showed that rescuers felt more comfortable and less exhausted in the narrow bed session compared with the wide bed session (P<.001 and < .001).

CONCLUSIONS

When rescuers performed chest compressions on an emergency stretcher, chest compression quality increased, and the fatigue of rescuers decreased compared with a standard hospital bed. Therefore, we propose a narrow bed for critically ill inpatients with high risk of cardiac arrest.

Resuscitators who compared four simulated infant cardiopulmonary resuscitation methods favoured the three-to-one compression-to-ventilation ratio

AIM

Suboptimal cardiopulmonary resuscitation (CPR) is associated with a poor outcome, and international guidelines state that resuscitators should optimise compression and ventilation techniques with as few interruptions as possible. We investigated compression and ventilation quality during simulated CPR with four compression-to-ventilation (C:V) methods.

METHODS

In this crossover manikin study, 42 pairs of doctors, nurses, midwives and sixth-year medical students from two Norwegian hospitals provided two-minute resuscitation using the 3:1, 9:3 and 15:2 C:V methods and continuous chest compressions at 120 per minute with asynchronous ventilations (CCaV-120). We measured chest compression, ventilation mechanics and the resuscitators' preferences.

RESULTS

C:V methods 3:1 and 9:3 provided comparable chest compressions and ventilation mechanics, whereas 15:2 produced fewer ventilations and lower minute volumes. The CCaV-120 method was significantly less effective than the 3:1 C:V ratio method: the chest compression depth was 1.9 mm lower, there were 25 fewer chest compressions and 21 fewer ventilations per minute, and the minute volume was 69 mL lower. The 3:1 C:V method also provided better coordination between resuscitators.

CONCLUSION

Our comparison of four simulated infant cardiopulmonary resuscitation methods favoured the 3:1 C:V method, and the multidisciplinary group of participants felt it offered the best level of coordination between resuscitators.

Rescuers' physical fatigue with different chest compression to ventilation methods during simulated infant cardiopulmonary resuscitation

OBJECTIVE

To assess development of objective, subjective and indirect measures of fatigue during simulated infant cardiopulmonary resuscitation (CPR) with two different methods.

METHODS

Using a neonatal manikin, 17 subject-pairs were randomized in a crossover design to provide 5-min CPR with a 3:1 chest compression (CC) to ventilation (C:V) ratio and continuous CCs at a rate of 120 min(-1) with asynchronous ventilations (CCaV-120). We measured participants' changes in heart rate (HR) and mean arterial pressure (MAP); perceived level of fatigue on a validated Likert scale; and manikin CC measures.

RESULTS

CCaV-120 compared with a 3:1 C:V ratio resulted in a change during 5-min of CPR in HR 49 versus 40 bpm (p = 0.01), and MAP 1.7 versus -2.8 mmHg (p = 0.03); fatigue rated on a Likert scale 12.9 versus 11.4 (p = 0.2); and a significant decay in CC depth after 90 s (p = 0.03).

CONCLUSIONS

The results indicate a trend toward more fatigue during simulated CPR in CCaV-120 compared to the recommended 3:1 C:V CPR. These results support current guidelines.

Performance of cardiopulmonary resuscitation during prolonged basic life support in military medical university students: A manikin study

BACKGROUND

The quality of chest compressions can be significantly improved after training of rescuers according to the latest national guidelines of China. However, rescuers may be unable to maintain adequate compression or ventilation throughout a response of average emergency medical services because of increased rescuer fatigue. In the present study, we evaluated the performance of cardiopulmonary resuscitation (CPR) in training of military medical university students during a prolonged basic life support (BLS).

METHODS

A 3-hour BLS training was given to 120 military medical university students. Six months after the training, 115 students performed single rescuer BLS on a manikin for 8 minutes. The qualities of chest compressions as well as ventilations were assessed.

RESULTS

The average compression depth and rate were 53.7±5.3 mm and 135.1±15.7 compressions per minute respectively. The proportion of chest compressions with appropriate depth was 71.7%±28.4%. The average ventilation volume was 847.2±260.4 mL and the proportion of students with adequate ventilation was 63.5%. Compared with male students, significantly lower compression depth (46.7±4.8 vs. 54.6±4.8 mm, P<0.001) and adequate compression rate (35.5%±26.5% vs. 76.1%±25.1%, P<0.001) were observed in female students.

CONCLUSIONS

CPR was found to be related to gender, body weight, and body mass index of students in this study. The quality of chest compressions was well maintained in male students during 8 minutes of conventional CPR but declined rapidly in female students after 2 minutes according to the latest national guidelines. Physical fitness and rescuer fatigue did not affect the quality of ventilation.

Up-down hand position switch may delay the fatigue of non-dominant hand position rescuers and improve chest compression quality during cardiopulmonary resuscitation: a randomized crossover manikin study

Previous studies have shown improved external chest compression (ECC) quality and delayed rescuer fatigue when the dominant hand (DH) was in contact with the sternum. However, many rescuers prefer placing the non-dominant hand (NH) in contact with the sternum during ECC. We aimed to investigate the effects of up-down hand position switch on the quality of ECC and the fatigue of rescuers during cardiopulmonary resuscitation (CPR). After completion of a review of the standard adult basic life support (BLS) course, every candidate performed 10 cycles of single adult CPR twice on an adult manikin with either a constant hand position (CH) or a switched hand position (SH) in random order at 7-day intervals. The rescuers' general characteristics, hand positions, physiological signs, fatigue appearance and ECC qualities were recorded. Our results showed no significant differences in chest compression quality for the DH position rescuers between the CH and SH sessions (p>0.05, resp.). And also no significant differences were found for Borg score (p = 0.437) or cycle number (p = 0.127) of fatigue appearance after chest compressions between the two sessions. However, for NH position rescuers, the appearance of fatigue was delayed (p = 0.046), with a lower Borg score in the SH session (12.67 ± 2.03) compared to the CH session (13.33 ± 1.95) (p = 0.011). Moreover, the compression depth was significantly greater in the SH session (39.3 ± 7.2 mm) compared to the CH session (36.3 ± 8.1 mm) (p = 0.015). Our data suggest that the up-down hand position switch during CPR may delay the fatigue of non-dominant hand position rescuers and improve the quality of chest compressions.

Barriers and facilitators to CPR knowledge transfer in an older population most likely to witness cardiac arrest: a theory-informed interview approach

BACKGROUND

We sought to identify perceived barriers and facilitators to cardiopulmonary resuscitation (CPR) training and performing CPR among people above the age of 55 years.

METHODS

We conducted semistructured qualitative interviews with a purposive sample of independent-living individuals aged 55 years and older from urban and rural settings. We developed an interview guide based on the constructs of the Theory of Planned Behaviour, which elicits salient attitudes, social influences and control beliefs potentially influencing CPR training and performance. Interviews were recorded, transcribed verbatim and analysed until achieving data saturation. Two independent reviewers performed inductive analyses to identify emerging themes, and ranked them by way of consensus.

RESULTS

Demographics for the 24 interviewees: mean age 71.4 years, women 58.3%, urban location 75.0%, single dwelling 58.3%, CPR training 79.2% and prior CPR on real victim 8.3%. Facilitators of CPR training included: (1) classes in a convenient location; (2) more advertisements; and (3) having a spouse. Barriers to taking CPR training included: (1) perception of physical limitations; (2) time commitment; and (3) cost. Facilitators of providing CPR included: (1) 9-1-1 CPR instructions; (2) reminders/pocket cards; and (3) frequent but brief updates. Barriers to providing CPR included: (1) physical limitations; (2) lack of confidence; and (3) ambivalence of duty to act in a large group.

CONCLUSIONS

We identified key facilitators and barriers for CPR training and performance in a purposive sample of individuals aged 55 years and older.

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.

Cardiopulmonary resuscitation and management of cardiac arrest

The best chance of survival with a good neurological outcome after cardiac arrest is afforded by early recognition and high-quality cardiopulmonary resuscitation (CPR), early defibrillation of ventricular fibrillation (VF), and subsequent care in a specialist center. Compression-only CPR should be used by responders who are unable or unwilling to perform mouth-to-mouth ventilations. After the first defibrillator shock, further rhythm checks and defibrillation attempts should be performed after 2 min of CPR. The underlying cause of cardiac arrest can be identified and treated during CPR. Drugs have a limited effect on long-term outcomes after cardiac arrest, although epinephrine improves the success of resuscitation, and amiodarone increases the success of defibrillation for refractory VF. Supraglottic airway devices are an alternative to tracheal intubation, which should be attempted only by skilled rescuers. Care after cardiac arrest includes controlled reoxygenation, therapeutic hypothermia for comatose survivors, percutaneous coronary intervention, circulatory support, and control of blood-glucose levels and seizures. Prognostication in comatose survivors of cardiac arrest needs a careful, multimodal approach using clinical and electrophysiological assessments after at least 72 h.