CPR Performance Research Articles

Quality of lay person CPR performance with compression:ventilation ratios 15:2, 30:2 or continuous chest compressions without ventilations on manikins

The new CPR guidelines emphasise chest compression depth and have increased the compression:ventilation ratio to cause less time intervals without chest compressions. How this change may influence the quality of chest compressions is not documented. Sixty-eight volunteers among travellers at Oslo international airport and a senior citizen centre performed 5 min of CPR on a manikin with compression:ventilation ratios 15:2, 30:2 or continuous chest compressions. Median age was 37.5 years (range 15-87), 59% were men, and 71% reported CPR training median 8 years (3-15) previously. Three of 22, 4 of 23 and 3 of 23 subjects in the 15:2, 30:2 and continuous compressions groups respectively stopped before 5 min had passed. Mean compression depth was 41 +/- 11, 45 +/- 8 and 30 +/- 8 mm, respectively. Depth was reduced as a function of time in the continuous compression group. Number of compressions per minute was 40 +/- 9, 43 +/- 14 and 73 +/- 24 and percent no flow time 49 +/- 13%, 38 +/- 20% and 1 +/- 2%, respectively. In conclusion, continuous chest compressions without ventilations gave significantly more chest compressions per minute, but with decreased compression quality. No flow time for 30:2 was significantly less than for 15:2.

Incomplete chest wall decompression: A clinical evaluation of CPR performance by trained laypersons and an assessment of alternative manual chest compression–decompression techniques

Complete chest wall recoil improves hemodynamics during CPR by generating relatively negative intrathoracic pressure, which draws venous blood back to the heart, providing cardiac preload prior to the next chest compression. This study was designed to assess the quality of CPR delivered by trained laypersons and to determine if a change in CPR technique or hand position would improve complete chest wall recoil, while maintaining adequate duty cycle, compression depth, and proper hand position placement. Standard manual CPR and three alternative manual CPR approaches were assessed. This randomized prospective trial was performed on an electronic test manikin. Thirty laypersons (mean age of 40.6 years (range 28-55)), who were trained in CPR within the last 24 months, signed an informed consent and participated in the trial. Subjects performed 3 min of CPR on a Laerdal Skill Reportertrade mark CPR manikin using the Standard Hand Position followed by 3 min of CPR (in random order) using three alternative CPR techniques: (1) Two-Finger Fulcrum Technique - lifting the heel of the hand slightly but completely off the chest during the decompression phase of CPR using the thumb and little finger as a fulcrum; (2) Five-Finger Fulcrum Technique - lifting the heel of the hand slightly but completely off the chest during the decompression phase of CPR using all five fingers as a fulcrum; (3) Hands-Off Technique - lifting the heel and all fingers of the hand slightly but completely off the chest during the decompression phase of CPR. The participants did not know the purpose of the study prior to, or during this investigation. Adequate compression depth was poor for all hand positions tested and ranged only from 18.6 to 35.7% of all compressions. When compared with the Standard Hand Position, the Hands-Off Technique decreased the mean compression duty cycle from 39.0 +/- 1.0 to 33.5 +/- 1.0%, (P < 0.0001) but achieved the highest rate of complete chest wall recoil (92.5% versus 24.1%, P < 0.0001) and was 46.3 times more likely to provide complete chest wall recoil (OR: 46.3; CI: 16.4-130.3). There were no significant differences in accuracy of hand placement, adequate depth of compression, or perceived discomfort with its use compared with the Standard Hand Position. The Hands-Off Technique decreased compression duty cycle but was 46.3 times more likely to provide complete chest wall recoil (OR: 46.3; CI: 16.4-130.3) compared to the Standard Hand Position without differences in accuracy of hand placement, adequate depth of compression, or perceived discomfort with its use. All forms of manual CPR tested (including the Standard Hand Position) in trained laypersons produced an inadequate depth of compression for two-thirds of the time. These data support development and testing of more effective layperson CPR training programmes and more effective means to deliver manual as well as mechanical CPR.

Physical strain during CPR-Comparing 30:2 versus 15:2

For basic life support the new guidelines of 2005 recommend a compression-ventilation-ratio of 30:2 [1]. Previous studies have shown a decrease in quality of chest compression with longer compression periods [2]. Furthermore, physical fitness seems to have a significant impact on effective chest compression [3]. Therefore, we investigated the quality of chest compression and physical strain during a 9Ymin CPR interval comparing 30:2 and 15:2. Moreover, we tested in which way physical strain develops if candidates were corrected in performing chest compression according to the guidelines. Method: 30 male and 10 women experienced in CPR were tested. Before performing CPR every candidate had to perform an endurance test by cycling and rowing. Depth, compression frequency and compression point were recorded by a Laerdal Rescuci Anne Skill Reporting System to evaluate the quality of chest compression. In the course of the endurance test and during CPR the heart rate, non invasive blood pressure, capillary lactate were measured and, with a mobile spiroergometryunit, oxygen up-take and CO2-production were recorded in order to evaluatephysical fitness and strain. Results: Final results will be presentedat the congress. Preliminary data suggest, that 30:2 is more exhausting than 15:2 especially for candidates with low physical fitness and low body weight. Candidates seem to adapt their CPR performance to their personal fitness. Correct CPR was more exhausting than non-correct. However, significant more candidates evaluated 30:2 more convenient than 15:2.

CPR Training and CPR Performance: Do CPR-trained Bystanders Perform CPR?

CPR Training and CPR Performance: Do CPR-trained Bystanders Perform CPR?

Relationship between knowledge of cardiopulmonary resuscitation guidelines and performance

Despite widespread training with CPR guidelines, CPR is often poorly performed. We explore relationships between knowledge of CPR guidelines and performance (compression rate, compression depth, compression to ventilation ratio, and ventilation volume). Sixty professional EMTs were sampled at 26 randomly ordered EMS response stations from an urban system of 31 stations. A recording manikin and video model were used to assess performance in a standardized scenario, and a survey was used to assess guideline knowledge. Survey and performance outcomes were categorized prospectively as correct or incorrect based on the International CPR Guidelines from 2000. Relationships were modeled with logistic regression. Covariates included years of work experience, frequency of CPR performance, and ALS versus BLS EMT level. Compression rate was between 80 and 120 min(-1) in 56% (33/59) of trials. Compression depth was 1.5-2 in. in 39% (23/59), compression to ventilation ratio approximated to 15:2 in 42% (25/59), and ventilation volume was 800-1,200 cm(3) in 13% (8/60). Accurate knowledge of the CPR guidelines was associated with better performance of chest compression rate and compression to ventilation ratio. Adjusted OR (95% CI) were 4.6 (1.2-18.1) for compression rate, 1.7 (0.4-6.5) for compression depth, 4.5 (1.1-18.5) for compression to ventilation ratio, and 9.0 (0.2-351) for ventilation volume. Although accurate knowledge of guidelines is associated with increased odds of correct performance of some aspects of CPR, overall performance remains poor.

CPR Education before Internship

Background and purpose: The importance of training basic and advanced life support for undergraduates and graduated physicians are now widely recognized. Graduates of medical schools in Iran immediately get license to practice medicine without any supervision. Therefore, Clarification of the best phases for training CPR and the optimum mastery level in each phase is very important. This study is an attempt to find out the ideas of stakeholders about training CPR before internship, the experience needed at the beginning of internship, the best phase for training it and the assessment method. Methods: It is a survey study designed in Isfahan University of Medical Sciences to investigate the opinions of head-nurses, interns, residents and educational directors (in ten clinical departments/wards) about training CPR before internship. Respondents completed self administered anonymous questionnaires. The questionnaires’ items covered opinions of respondents about CPR as interns’ duty, level of experience; best course for training and the assessment method. Meanwhile, views of participants were compared against educational directors’ idea by Fisher exact test. Results: 32 head-nurse, 285 interns, 13 resident and15 educational directors participated in the study and all agreed with CPR as interns’ duty in all clinical wards. Although, directors had different idea about level of experience for CPR to be achieved by interns, residents suggested level 3 of experience. According to the results externship is the best phase for CPR training and combination of observation and OSCE suggested as the best assessment method. Conclusion: To prepare the graduates achieving full competency in CPR performance, it is needed to implement training programs before internship. Internship is the best phase for getting expertise in CPR. Based on the results CPR considered as interns’ responsibility and medical schools should feel confidence about the competency of interns in CPR at the beginning of internship. Keywords : C ARDIOPULMONARY R ESUSCITATION / EDUCATION , E DUCATIONAL M EASUREMENT S CHOOLS , M EDICAL S TUDENTS , M EDICAL

Retention of CPR performance in anaesthetists

The objective of this study was to evaluate retention of ALS knowledge and performance among anaesthesiologists, who, in Italy, respond to in-hospital emergencies as team leaders. 47 anaesthesiologists (23 consultants and 24 residents) were invited at one weeks notice to attend a re-evaluation session, 6 months after successful completion of an ERC ALS course. Knowledge retention was assessed by a multiple choice question test, and skills and management by evaluation of performance as team leader in one of the six standardized CAStest scenarios. During the performance, the timeliness of first defibrillation, completion of the three shock sequence, adrenaline (epinephrine) administration and intubation were recorded. Results were compared between consultants and residents. Compared to the results at the end of the ALS course, the percent of correct answers to the multiple choice question test decreased from 85.89 +/- 5.28% to 79.45 +/- 6.62% (P < 0.001), the number of candidates achieving a pass performance decreased from 47/47 to 30/47 (P < 0.001). Time to first defibrillation was 73.38 +/- 18.72 s, time for completion of the third defibrillation was 113.04 +/- 35.58 s and subsequent ALS interventions were very delayed or forgotten. Comparison between consultants and residents showed that consultants retained knowledge information better, skills decreased comparably in both groups and residents performed tasks faster. The significant decay of ALS skills 6 months post-ALS recorded among anaesthesiologists supports the need for periodical reinforcement during intervals before recertification.

Appendix 1: Worksheet topics and authors

Appendix 1: Worksheet topics and authors

CPR Performance Does Not Follow Guidelines

CPR Performance Does Not Follow Guidelines

A comparison of CPR delivery with various compression-to-ventilation ratios during two-rescuer CPR

Background: The number of chest compressions required for optimal generation of coronary perfusion pressure remains unknown although studies examining compression-to-ventilation ratios higher than 15:2 (C:V) in animals have reported higher C:V to be superior for return of spontaneous circulation and neurologic outcome. We examined human performance of two-rescuer CPR using various C:V. Methods: Thirty six EMT-Basic students in their final week of training performed two-rescuer CPR using C:V of 15:2, 30:2, 40:2, 50:2, and 60:2 on a recording resuscitation manikin. Compression and ventilation variables were recorded by computer while the number of pauses for ventilations and the hands-off time (time not spent performing chest compressions) were abstracted by hand. Data were analyzed by ANOVA and significant differences from the standard treatment of C:V = 15:2 were assessed by Tukey's HSD post hoc test. Findings: The number of compressions delivered per minute increased with increasing C:V while the hands-off time and pauses for ventilations decreased. All comparisons were significantly different from C:V = 15:2 ( P < 0.001). The ventilation numbers decreased with increasing C:V although mean minute volume exceeded 1 l for all C:V. Interpretation: A 15:2 compression-to-ventilation ratio when performed during two-rescuer CPR results in 26 s of hands off time each minute while only delivering 60 compressions. Alternative C:V ratios of 30:2, 40:2, 50:2, and 60:2 all exceed the AHA recommended 80 compressions/min while still delivering a minute volume in excess of 1 l.

Recurrent ventricular fibrillation in out-of-hospital cardiac arrest after defibrillation by police and firefighters: Implications for automated external defibrillator users

To determine the prevalence and frequency of recurrent ventricular fibrillation (VF) in patients defibrillated by police and firefighters only and to determine its relation to survival. Retrospective observational study. Out of hospital. Individuals with witnessed VF arrest in the Rochester, MN, ambulance public service area who had defibrillatory shocks delivered by police and firefighters and return of spontaneous circulation with shocks only. Electrocardiograms were recovered from data cards in automated external defibrillators used by police (n = 49) or firefighters (n = 18) to deliver shocks from December 1996 through December 2003 in the Rochester, MN, ambulance public service area. Patients with witnessed VF arrest were identified for recurrent VF after initial shock success (first one to three shocks). Both police and firefighters deployed automated external defibrillators delivering nonescalating 150-J biphasic truncated exponential waveform shocks (ForeRunner Automated External Defibrillator, Phillips/Heartstream Operation, Seattle, WA). Among 67 patients, 30 (45%) survived to neurologically intact discharge (overall performance category score of 1 in 29 patients and score of 2 in one patient). Twenty-nine patients (43%) regained spontaneous circulation with shocks only and 25 of 29 (86%) survived. VF recurred in 35 of the 67 patients (52%) while being cared for by police or firefighters. Of these 35 patients, no relation was found between the prevalence or frequency of VF recurrence and survival. VF recurrence is frequent, variable in time of onset, and unrelated to the performance of bystander CPR. The prevalence and frequency of VF recurrence were unpredictable and do not adversely affect survival. Thus, vigilance for recurrent VF is essential to ensure the survival of patients who are in the care of first responders, even after initial restoration of pulses with shocks.

6. The Three-Phase EMS Cardiac Arrest Model for Ventricular Fibrillation

Cardiac arrest is responsible for significant morbidity and mortality, with consistently poor outcomes despite the rapid availability of prehospital personnel for defibrillation attempts in patients with ventricular fibrillation (VF). Recent evidence suggests a period of CPR prior to defibrillation attempts may improve outcomes in patients with 4- to 10-minute down times (time of arrest to defibrillation). The purpose of this study was to determine cardiac arrest outcomes in our community and explore the relationship between down time, performance of bystander CPR, and survival.

Improving CPR performance using an audible feedback system suitable for incorporation into an automated external defibrillator

Background: It has been shown that a computer-based audible feedback system can improve acquisition and retention of basic life support (BLS) skills. This system is being developed to work in association with an automated external defibrillator (AED). Aim: To determine if such a feedback system is likely to improve the quality of CPR performed by trained nurses whilst using an AED. Method: Thirty-six general nurses performed 3 min of BLS on a manikin connected to a laptop computer running an experimental software program. After initial testing they were randomly allocated to control or ‘feedback’ groups. Both groups then performed a further 3 min of BLS, but those in the feedback group received audible corrective instructions from the computer when errors of technique were detected. Results: The group receiving feedback were significantly better than the control group at performing inflations ( P=0.004) and achieving the correct depth of chest compression ( P<0.0005). Conclusions: The results suggest that if the feedback system were to be incorporated into an AED, it could lead to better performance of CPR during a resuscitation attempt.

Randomised controlled trials of staged teaching for basic life support: 2. Comparison of CPR performance and skill retention using either staged instruction or conventional training

Teaching CPR in stages is a strategy designed to improve skill acquisition and retention. This method has been compared with conventional teaching in a randomised trial involving 495 volunteers. The first (‘bronze’) stage was simplified by omitting ventilation and giving compressions in sets of 50 with pauses to open the victim's airway; in the second (‘silver’) stage ventilation was introduced in a ratio of 50 compressions to five breaths, and in the third (‘gold’) stage, the volunteers were converted to conventional CPR. 51% of those taught by this method reattended for the second (‘silver’) stage compared with 25% who were taught conventional CPR and advised to return for a revision session. 38% of the staged group reattended for the third (‘gold’) compared with 8% for the conventional group. Modest improvement in skill acquisition has earlier been reported for the ‘bronze’ stage teaching, and this has been followed by better performance in some of the components tested after the subsequent stages. Comparisons after the ‘gold’ stage were limited by the small numbers who reattended for a third session of conventional training, but no special difficulties were noted in changing the ratio of compressions to ventilation that was necessary to convert the staged training volunteers to conventional CPR. The increased number of compressions that can be achieved by teaching ‘bronze’ stage CPR with no ventilation was retained, to a lesser degree, when the ‘silver’ ratio of 50 compressions to five breaths was compared with the conventional 15:2 ratio. Our observations suggest that during the first critical 8 min of a resuscitation attempt, 58% more compressions might be delivered by using the 50:5 ratio — an increase that is likely to result in a significant augmentation of blood flow with important clinical implications. More comparative information will become available when the results of unannounced home testing are analysed.

Part 2: Ethical Aspects of CPR and ECC

Part 2: Ethical Aspects of CPR and ECC

Part 12: From Science to Survival

Part 12: From Science to Survival

Fitness Improves CPR Performance

Fitness Improves CPR Performance

Skill mastery in public CPR classes

Effectiveness of CPR performance on a manikin was evaluated immediately after training in public CPR classes by trained independent observers using validated measures and procedures. An instrumented manikin was used to assess critical skills thought to be related to survival following out-of-hospital cardiac arrest (compressions and ventilations), applying standards of the American Heart Association. The 226 subjects were enrolled in CPR classes offered to the public by the American Red Cross and the American Heart Association. Fifty percent of subjects performed 2% or fewer compressions correctly (the most common error being insufficient depth), and 50% performed 10% or fewer of ventilations correctly (the most common error being insufficient volume). Sixty-five percent failed to achieve a compression rate of 80 to 100/min. Forty-five percent of subjects failed to open the airway prior to a breathing check, 50% failed to adequately assess breathing, and 53% did not perform an adequate pulse check. Nearly half of all subjects made at least four errors in assessment and sequencing of skills. According to published criteria, trainee performance of CPR is poor. Failure in critical skills may contribute to poor survival rate following out-of-hospital cardiac arrest. CPR training programs must be developed with attention to learner outcomes.

Outcome From Out-of-hospital Cardiac Arrest Caused by Nonventricular Arrhythmias: Contribution of Successful Resuscitation to Overall Survivorship Supports the Current Practice of Initiating Out-of-hospital ACLS

Study objective: Studies indicate that ventricular tachycardia (VT) and ventricular fibrillation (VF) are no longer the most common rhythms initially documented in out-of-hospital sudden cardiac death. Although the outcome from asystole and rhythms designated as pulseless electrical activity (PEA) is reported as poor (approximately 1% survival), resuscitative efforts for these patients are still encouraged. The purpose of this study was to determine the potential contribution that this patient group makes to overall survivorship. Methods: During this 2-year prospective study, all patients in cardiopulmonary arrest who were transported to the study institution after out-of-hospital Advanced Cardiac Life Support (ACLS) interventions were considered eligible for inclusion. Patients younger than 18 years of age and those in posttraumatic arrest were excluded. Age, sex, first-documented arrest rhythm, presence of a witness to the arrest, performance of bystander CPR, survival to hospital discharge, and functional status at discharge were recorded. Results: A total of 197 patients met the inclusion criteria. The initial rhythm was VF/VT in 59 (30%; 95% confidence interval [CI], 24% to 37%) and asystole/PEA in 138 (70%; 95% CI, 64% to 76%). There was 1 hospital survivor in the VT/VF group; 9 patients (7%; 95% CI, 4% to 13%) in the asystole/PEA group survived to hospital discharge. Of the asystole/PEA survivors, 100% (95% CI, 66% to 100%) had a witnessed arrest and 56% (95% CI, 21% to 86%) received bystander CPR. Fifty-six percent (95% CI, 21% to 86%) of the asystole/PEA survivors were discharged at a functional level equivalent to that preceding arrest. Conclusion: In this study, patients in asystole/PEA comprised 90% of the survivors. The outcome for patients with asystole/PEA whose arrest was witnessed and who received bystander CPR may be greater than previously estimated and supports the current practice of initiating aggressive out-of-hospital ACLS in this patient group. [Stratton SJ, Niemann JT: Outcome from out-of-hospital cardiac arrest caused by nonventricular arrhythmias: Contribution of successful resuscitation to overall survivorship supports the current practice of initiating out-of-hospital ACLS. Ann Emerg Med October 1998;32:448-453.]

Ran domize d, Controlle d Trial of Vi deo Self-Instruction Versus Tra ditional CPR Training

Study objective: We conducted a prospective, randomized, controlled trial to test the hypothesis that a 34-minute video self-instruction (VSI) training program for adult CPR would yield comparable or better CPR performance than the current community standard, the American Heart Association Heartsaver course. Methods: Incoming freshman medical students were randomly assigned to VSI or the Heartsaver CPR course. Two to 6 months after training, we tested subjects to determine their ability to perform CPR in a simulated cardiac arrest setting. Blinded observers used explicit criteria to assess our primary outcome, CPR performance skill. In addition, we assessed secondary outcomes including sequential performance of individual skills, ventilation and chest compression characteristics, and written tests of CPR-related knowledge and attitudes. Results: VSI trainees displayed superior overall performance compared with traditional trainees. Twenty of 47 traditional trainees (43%) were judged not competent in their performance of CPR, compared with only 8 of 42 VSI trainees (19%; absolute difference, 24%; 95% confidence interval, 5% to 42%). Conclusion: In a group of incoming freshman medical students, we found that a half-hour of VSI resulted in superior overall CPR performance compared with that in traditional trainees. If validated by further research, VSI may provide a simple, quick, and inexpensive alternative to traditional CPR instruction for health care workers and, perhaps, the general population. [Todd KH, Braslow A, Brennan RT, Lowery DW, Cox RJ, Lipscomb LE, Kellermann AL: Randomized, controlled trial of video self-instruction versus traditional CPR training. Ann Emerg Med March 1998;31:364-369.]