Standard cardiopulmonary resuscitation versus chest compressions only after out-of-hospital cardiac arrest: a protocol for a systematic review and meta-analysis

INTRODUCTION

The 2020 American Heart Association guidelines encourage lay rescuers to provide chest compression-only cardiopulmonary resuscitation to simplify the process and encourage cardiopulmonary resuscitation initiation. However, recent clinical trials had contradictory results about chest compression-only cardiopulmonary resuscitation. This study will aim to compare standard and chest compressions-only cardiopulmonary resuscitation after out-of-hospital cardiac arrest.

METHODS AND ANALYSIS

This study will retrieve only randomised and quasi-randomised controlled trials from the Cochrane Library, PubMed, Web of Science and Embase databases. Data on study design, participant characteristics, intervention details and outcomes will be extracted by a unified standard form. Primary outcomes to be assessed are hospital admission, discharge, and 30-day survival, and return of spontaneous circulation. The Grading of Recommendations, Assessment, Development and Evaluation framework will evaluate the quality of evidence. Cochrane's tool for assessing the risk of bias will evaluate risk deviation. If the I2 statistic is lower than 40%, the fixed-effects model will be used for meta-analysis. Otherwise, the random-effects model will be used. The search will be performed following the publication of this protocol (estimated to occur on 30 December 2024).

DISCUSSION

This study will evaluate the effect of chest compression-only cardiopulmonary resuscitation after out-of-hospital cardiac arrest and provide evidence for cardiopulmonary resuscitation guidelines.

ETHICS AND DISSEMINATION

No patient or public entity will be involved in this study. Therefore, the study does not need to be ethically reviewed. The results of the study will be disseminated through peer-reviewed journal publications and committee conferences.

PROSPERO REGISTRATION NUMBER

CRD42021295507.

The impact of resuscitation guideline terminology on quality of dispatcher-assisted cardiopulmonary resuscitation: A randomised controlled manikin study

BACKGROUND

Cardiopulmonary resuscitation (CPR) guidelines vary in the terminology used to describe target chest compression depth, which may impact CPR quality. We investigated the impact of using different chest compression depth instruction terminologies on CPR quality.

METHODS

We conducted a parallel group, three-arm, randomised controlled manikin trial in which individuals without recent CPR training were instructed to deliver compression-only CPR for 2-min based on a standardised dispatcher-assisted CPR script. Participants were randomised in a 1:1:1 ratio to receive CPR delivery instructions that instructed them to deliver chest compressions based on the following terminologies: 'press at least 5 cm', 'press approximately 5 cm' or 'press hard and fast.' The primary outcome was compression depth, measured in millimetres.

RESULTS

Between October 2017 and June 2018, 330 participants were randomised to 'at least 5 cm' (n = 109), 'approximately 5 cm' (n = 110) and 'hard and fast' (n = 111), in which mean chest compression depth was 40.9 mm (SD 13.8), 35.4 mm (SD 14.1), and 46.8 mm (SD 15.0) respectively. Mean difference in chest compression depth between 'at least 5 cm' and 'approximately 5 cm' was 5.45 (95% confidence interval (95% CI) 0.78-10.12), between 'hard and fast' and 'approximately 5 cm' was 11.32 (95% CI 6.65-15.99), and between 'hard and fast' and 'at least 5 cm' was 5.87 (95% CI 1.21-10.53). Chest compression rate and count were both highest in the 'hard and fast' group.

CONCLUSIONS

The use of 'hard and fast' terminology was superior to both 'at least 5 cm' and 'approximately 5 cm' terminologies.

TRIAL REGISTRATION

ISRCTN15128211.

The Efficacy of Chest Compressions in the Bell 407

OBJECTIVE

The Air Medical industry is fraught with obstacles to patient care and providers can recognize that several sub-groups of patients can provide very challenging scenarios while in flight. However, the patient experiencing cardiac arrest in flight is, by its very nature, one that poses the most severe risk to the patient and provider. This study seeks to explore the capability of a highly trained emergency medical provider to provide adequate chest compressions while in a Bell 407 helicopter.

METHODS

59 participants were evaluated in two separate scenarios. Scenario A consisted of 2 rounds of of 200 chest compressions performed on a flat, uncrowded surface. Scenario B consisted of 200 chest compressions performed in the cabin of a Bell 407. Participants performed 2 rounds of 200 chest compressions. The results were then compared to each other and to the AHA 2010 CPR guidelines.

RESULTS

The findings of the study show that compressions performed in the aircraft do not meet AHA guidelines for chest compressions in regard to depth and duration of compressions. The deviation from guideline in regard to rate was found to be not statistically significant.

CONCLUSION

Chest compressions performed in a Bell 407 helicopter do not meet AHA guidelines.

The TrueCPR device in the process of teaching cardiopulmonary resuscitation: A randomized simulation trial

BACKGROUND

International resuscitation guidelines emphasize the importance of high quality chest compressions, including correct chest compression depth and rate and complete chest recoil. The aim of the study was to assess the role of the TrueCPR device in the process of teaching cardiopulmonary resuscitation in nursing students.

METHODS

A prospective randomized experimental study was performed among 94 first year students of nursing. On the next day, the participants were divided into 2 groups-the control group practiced chest compressions without the use of any device for half an hour, and the experimental group practiced with the use of TrueCPR. Further measurement of chest compressions was performed after a month.

RESULTS

The chest compression rate achieved the value of 113 versus 126 (P < .001), adequate chest compression rate (%) was 86 versus 68 (P < .001), full chest release (%) 92 versus 69 (P = .001), and correct hand placement (%) 99 versus 99 (P, not significant) in TrueCPR and standard BLS groups, respectively. As for the assessment of the confidence of chest compression quality, 1 month after the training, the evaluation in the experimental group was statistically significantly higher (91 vs 71; P < .001) than in the control group.

CONCLUSIONS

Cardiopulmonary resuscitation training with the use of the TrueCPR device is associated with better resuscitation skills 1 month after the training. The participants using TrueCPR during the training achieved a better chest compression rate and depth with in international recommendations and better full chest release percentage and self-assessed confidence of chest compression quality comparing with standard cardiopulmonary resuscitation training.

Can rescuers accurately deliver subtle changes to chest compression depth if recommended by future guidelines?

BACKGROUND

A recent study reported that a compression depth of 4.56 cm optimised survival following cardiac arrest, which is at variance with the current guidelines of 5.0-6.0 cm. A reduction in recommended compression depth is only likely to improve survival if healthcare professionals can accurately deliver a relatively small change in target depth. This study aimed to determine if healthcare professionals could accurately judge their delivered compression depth by 0.5 cm increments.

METHOD

This randomised interventional trial asked BLS-trained healthcare professionals to complete two minutes of continuous chest compressions on an adult manikin, randomised (without any feedback device), to compress to one of three target depth ranges of 4.0-5.0 cm, 4.5-5.5 cm or 5.0-6.0 cm, at the recommended rate of 100-120 compressions min^-1. Basic demographic data, compression rate, and compression depth were recorded.

RESULTS

One hundred and one participants were recruited, of whom one withdrew. Median depths of 3.66 cm (IQR: 3.37-4.16 cm), 4.13 cm (IQR: 3.65-4.36 cm) and 4.76 cm (IQR: 4.16-5.24 cm) were found for the target depths of 4.0-5.0 cm (n = 30), 4.5-5.5 cm (n = 35) and 5.0-6.0 cm (n = 35) respectively (P < 0.001). Overall, 18 participants successfully compressed to their target depth.

CONCLUSIONS

Rescuers are able to judge 0.5 cm differences in compression depth with precision, but remain unable to accurately judge overall target depth. Reducing the current recommended compression depth to 4.56 cm is likely to result in delivered compressions significantly below the optimal depth.

2017 American Heart Association Focused Update on Adult Basic Life Support and Cardiopulmonary Resuscitation Quality: An Update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care

Cardiopulmonary resuscitation is a lifesaving technique for victims of sudden cardiac arrest. Despite advances in resuscitation science, basic life support remains a critical factor in determining outcomes. The American Heart Association recommendations for adult basic life support incorporate the most recently published evidence and serve as the basis for education and training for laypeople and healthcare providers who perform cardiopulmonary resuscitation.

Evaluation of new two-thumb chest compression technique for infant CPR performed by novice physicians. A randomized, crossover, manikin trial

BACKGROUND

The impact of high-quality chest compressions during CPR for the patients' outcome is undisputed, as it is essential for maintaining vital organ perfusion. The aim of our study is to compare the quality of chest compression (CC) and ventilation among the two current standard techniques with our novel "nTTT" technique in infant CPR.

METHODS

In this randomized crossover, manikin trial, participants performed CCs using three techniques in a randomized sequence: standard two finger technique (TFT); standard two thumb technique (TTHT), and the 'new two-thumb technique' (nTTT). The novel method of CCs in an infant consists in using two thumbs directed at the angle of 90° to the chest while closing the fingers of both hands in a fist.

RESULTS

Median depth compression using the distinct chest compression techniques varied and amounted to 26 [IQR, 25-28] mm for TFT, and 39 [IQR, 39-39] mm for TTHT as well as for nTTT. Best percentage of fully released compressions were received using TFT (100[100-100] %), then in the case of nTTT (99[98-100] %), and the worst in situation where TTHT (18[14-19] %). was used. The fastest chest compression rate was achieved with TFT (134[IQR, 129-135]/min) and the slowest when using nTTT (109 [IQR, 105-111]/min).

CONCLUSIONS

We found that our new nTTT technique's performance, in terms of compression depth, hands-off time, and ventilation quality, is comparable to the current standards. Based on our findings of this initial manikin study, the nTTT technique is superior to TFT in many of parameters that are vital to a quality chest compression during pediatric CPR.

Cardiopulmonary Resuscitation Quality by Helicopter Rescue Swimmers While Flying

OBJECTIVE

Our objective was to assess the cardiopulmonary resuscitation (CPR) quality by helicopter rescue swimmers (HRSs) while flying.

METHODS

Twenty HRSs from the Spanish Maritime Safety took part in this study. The research protocol included 2 phases: a baseline test (5 minutes of CPR on land) and a challenge test (5 minutes of CPR on a Sikorsky S-61N helicopter in-flight). A Laerdal Resusci Anne mannequin with Laerdal PC Skill Reporting (Stavanger, Norway) was used to register CPR variables.

RESULTS

CPR quality on land versus in-flight was not significantly different. The mean chest compression (CC) depth (52.6 mm on land vs. 51.9 mm in-flight) was inside the recommended range, but mean CC rate (133 vs. 132 per minute), tidal volume (752 vs. 888 mL), and hands-off time (9 per cycle in both tests) were above the 2015 recommended goal. Incomplete chest re-expansion was observed in 19% of on land and 26% in-flight CCs. CPR quality was maintained throughout the 5-minute challenges.

CONCLUSION

HRSs are able to perform CPR in a flying helicopter with similar quality to CPR on land. They need additional training to avoid excessive CC rates, tidal volumes, and hands-off times and to permit chest re-expansion.

Improving Survival From Cardiac Arrest: A Review of Contemporary Practice and Challenges

Cardiac arrest is a common and lethal condition frequently encountered by emergency medicine providers. Resuscitation of persons after cardiac arrest remains challenging, and outcomes remain poor overall. Successful resuscitation hinges on timely, high-quality cardiopulmonary resuscitation. The optimal method of providing chest compressions and ventilator support during cardiac arrest remains uncertain. Prompt and effective defibrillation of ventricular arrhythmias is one of the few effective therapies available for treatment of cardiac arrest. Despite numerous studies during several decades, no specific drug delivered during cardiac arrest has been shown to improve neurologically intact survival after cardiac arrest. Extracorporeal circulation can rescue a minority of highly selected patients with refractory cardiac arrest. Current management of pulseless electrical activity is associated with poor outcomes, but it is hoped that a more targeted diagnostic approach based on electrocardiography and bedside cardiac ultrasonography may improve survival. The evolution of postresuscitation care appears to have improved cardiac arrest outcomes in patients who are successfully resuscitated. The initial approach to early stabilization includes standard measures, such as support of pulmonary function, hemodynamic stabilization, and rapid diagnostic assessment. Coronary angiography is often indicated because of the high frequency of unstable coronary artery disease in comatose survivors of cardiac arrest and should be performed early after resuscitation. Optimizing and standardizing our current approach to cardiac arrest resuscitation and postresuscitation care will be essential for developing strategies for improving survival after cardiac arrest.

Part 3: Adult Basic Life Support and Automated External Defibrillation: 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This review comprises the most extensive literature search and evidence evaluation to date on the most important international BLS interventions, diagnostics, and prognostic factors for cardiac arrest victims. It reemphasizes that the critical lifesaving steps of BLS are (1) prevention, (2) immediate recognition and activation of the emergency response system, (3) early high-quality CPR, and (4) rapid defibrillation for shockable rhythms. Highlights in prevention indicate the rational and judicious deployment of search-and-rescue operations in drowning victims and the importance of education on opioid-associated emergencies. Other 2015 highlights in recognition and activation include the critical role of dispatcher recognition and dispatch-assisted chest compressions, which has been demonstrated in multiple international jurisdictions with consistent improvements in cardiac arrest survival. Similar to the 2010 ILCOR BLS treatment recommendations, the importance of high quality was reemphasized across all measures of CPR quality: rate, depth, recoil, and minimal chest compression pauses, with a universal understanding that we all should be providing chest compressions to all victims of cardiac arrest. This review continued to focus on the interface of BLS sequencing and ensuring high-quality CPR with other important BLS interventions, such as ventilation and defibrillation. In addition, this consensus statement highlights the importance of EMS systems, which employ bundles of care focusing on providing high-quality chest compressions while extricating the patient from the scene to the next level of care. Highlights in defibrillation indicate the global importance of increasing the number of sites with public-access defibrillation programs. Whereas the 2010 ILCOR Consensus on Science provided important direction for the “what” in resuscitation (ie, what to do), the 2015 consensus has begun with the GRADE methodology to provide direction for the quality of resuscitation. We hope that resuscitation councils and other stakeholders will be able to translate this body of knowledge of international consensus statements to build their own effective resuscitation guidelines.

Optimal chest compression technique for paediatric cardiac arrest victims

BACKGROUND

The aim of this study was to assess the quality of chest compressions performed by inexperienced rescuers using three different techniques: two-hand, right one-hand, and left one-hand.

METHODS

We performed a prospective, randomised, crossover study in a simulated 6-year-old paediatric manikin model. Each participant performed 2-minute continuous chest compressions, using three different techniques. Chest compression quality data, including compression rate, compression depth, and residual leaning was recorded by a Q-CPR™ compression sensor connected to HeartStart MRx (Philips Healthcare, Andover, MA, USA). To examine trends in chest compression performance over time, each 2-minute period was divided into six consecutive 20-second epochs.

RESULTS

The 36 participants completed 108 two-minute trials, consisting of a total of 25,030 compressions. The mean compression rates [95% confidence interval] were as follows: two-hand, 116.8 [111.7-121.9]; left one-hand, 115.0 [109.9-120.1]; and right one-hand, 115.5 [110.4-120.6] (p = 0.565). The mean compression depth for two-hand was 38.7 mm (37.1-40.2), which was higher than for left one-hand (36.3 mm [34.8-37.9]) or right one-hand (35.4 mm [33.9-37.0]) (p < 0.001). Chest compression depth declined over time, regardless of the technique (p < 0.001). The pattern of compression depth change over time was similar for all techniques (p > 0.999). The residual leaning rate was higher with two-hand (40.7 [27.9-53.5]) than that for left one-hand (29.2 [16.4-42.0]) or right one-hand (25.8 [13.0-38.6]) (p = 0.021).

CONCLUSIONS

For paediatric cardiopulmonary resuscitation by inexperienced rescuers, the two-hand technique has the advantage of producing deeper compressions than the one-hand technique, but it is accompanied by more frequent residual leaning. For the one-hand techniques, the right and left hand produced chest compressions of similar quality.

Quality of continuous chest compressions performed for one or two minutes

OBJECTIVES

This study was designed to assess cardiopulmonary resuscitation quality and rescuer fatigue when rescuers perform one or two minutes of continuous chest compressions.

METHODS

This prospective crossover study included 148 lay rescuers who were continuously trained in a cardiopulmonary resuscitation course. The subjects underwent a 120-min training program comprising continuous chest compressions. After the course, half of the volunteers performed one minute of continuous chest compressions, and the others performed two minutes, both on a manikin model. After 30 minutes, the volunteers who had previously performed one minute now performed two minutes on the same manikin and vice versa.

RESULTS

A comparison of continuous chest compressions performed for one and two minutes, respectively, showed that there were significant differences in the average rate of compressions per minute (121 vs. 124), the percentage of compressions of appropriate depth (76% vs. 54%), the average depth (53 vs. 47 mm), and the number of compressions with no errors (62 vs. 47%). No parameters were significantly different when comparing participants who performed regular physical activity with those who did not and participants who had a normal body mass index with overweight/obese participants.

CONCLUSION

The quality of continuous chest compressions by lay rescuers is superior when it is performed for one minute rather than for two minutes, independent of the body mass index or regular physical activity, even if they are continuously trained in cardiopulmonary resuscitation. It is beneficial to rotate rescuers every minute when performing continuous chest compressions to provide higher quality and to achieve greater success in assisting a victim of cardiac arrest.

[Data from automated external defibrillators provide important information on the quality of in-hospital resuscitation]

International guidelines recommend monitoring the outcome following in-hospital cardiac arrest. Using data from automatic external defibrillators (AED) prospectively collected during a three-year period in a regional hospital, we evaluated the treatment quality of resuscitation. Time to defibrillation was acceptable, but quality of chest compressions did not comply with current international recommendations. AED use led to a high fraction of time with no chest compressions. Survival to discharge was 11%. Consequently, training in basic and advanced life support of hospital staff has been modified.

[Manual chest compression depth estimation based on integration reset mechanism]

To realize the measurement of the chest compression depth during the administration of manual cardiopulmonary resuscitation, two 3-axis digital accelerometers were applied for chest compression acceleration and environment acceleration acquisition, with one placed in the chest compression sensor pad, and the other placed in the back sensor pad. Then double integration was made for the acceleration-to-depth conversion with both of the accelerations after preprocessing. The method further included integration reset mechanism based on compression force, with the force point of a pre-determined threshold and the maximum force point as the starting point and the ending point of the integration, respectively. Moreover, a software compensation algorithm was implemented to further increase the accuracy of the depth estimation and reliability of the acceleration. The final performance of the compression depth estimation is within +/- 0.6 cm with 95% confidence of a total of 283 compressions. Accurate and real-time estimation of chest compression depth greatly facilitates the control of compression depth for the lifesaver during manual cardiopulmonary resuscitation.

New method of chest compression for infants in a single rescuer situation: thumb-index finger technique

We introduce a new method of external chest compression (ECC), an essential part of cardiopulmonary resuscitation, using a thumb and index finger method (TIFM) on infants, and compares, this with two standard methods of the two finger method (TFM) and the two-thumb encircling hands method (TTEM). Sixty trained PALS (Pediatric Advanced Life Support) providers were randomly assigned into three groups and provided one-rescuer ECC for a period of five continuous minutes. Results without coaching or feedback were recorded on a recording CPR simulator (Laerdal, Inc). ECC was performed according to the BLS recommendations of the International Liaison Committee on Resuscitation (ILCOR). The quality of ECC in the TFM group deviated considerably from guideline recommendations. The same parameters in the TTEM and new TIFM groups during this study were in accordance with the parameters recommended by the guidelines. Thus, our new TIFM technique of chest compression, in infants was shown to be better than the currently TFM, especially for achieving adequate compression depth and avoiding fatigue, and is equally as effective as the TTEM. We propose this new method (TIFM) should be considered as the method of choice in single rescuer situations.

Summary of the new 2010 American Heart Association Guidelines for Basic Life Support (CPR)

Approximately every 5 years, American Heart Association (AHA) experts review emerging scientific evidence and recent clinical experiences and update the AHA guidelines for basic and advanced life support procedures for in-hospital and out-of-hospital victims of life-threatening cardiac events. This article summarizes many of the 2010 changes in those guidelines as they apply to dental healthcare providers (HCP). More detailed information will be available in the near future as these guidelines are fully implemented and instructional materials are released by the AHA. Until they are trained in future AHA or American Red Cross (ARC) basic or advanced cardiac life support (BLS, ACLS) courses in 2011, dentists, dental assistants, dental hygienists, and office staff should continue to rely on the training and information they received in their most recent basic (and/or advanced cardiac) life support training course.

The impact of compliant surfaces on in-hospital chest compressions: effects of common mattresses and a backboard

PURPOSE

To evaluate, in a hospital setting, the influence of different, common mattresses, with and without a backboard, on chest movement during CPR.

DESIGN AND SETTING

Sixty CPR sessions (140s each, 30:2, C:R ratio 1:1) were performed using a manikin on standard hospital mattresses, with or without a backboard in combination with variable weights. Sternum-to-spine compression distance was controlled (range 30-60mm) allowing evaluation of the underlying compliant surface on total hand travel.

RESULTS

Movement of the caregiver's hands was significantly larger (up to 111mm at 50mm compression depth, p<0.0001) when sternum-to-spine compressions were performed without a backboard than with one. The extent of this variable extra travel effect depended on the type of mattress as well as the force of compression. Foam mattresses and air chamber systems act as springs and follow hand movement, while 'slow foam' mattresses incorporate time delays, making depth and force sensing harder. A backboard decreases the extra hand movement due to mattress effects by more than 50%, strongly reducing caregiver work.

CONCLUSIONS

Total vertical hand movement is significantly, and clinically relevantly much, larger than sternum-to-spine compression depth when CPR is performed on a mattress. Additional movement depends on the type of mattress and can be strongly reduced, but not eliminated, when a backboard is applied. The additional motion and increased work load adds extra complexity to in-hospital CPR. We propose that this should be taken into account during training by in-hospital caregivers.

Is the inter-nipple line the correct hand position for effective chest compression in adult cardiopulmonary resuscitation?

BACKGROUND

Despite the new release of CPR guidelines, there was insufficient evidence for or against a specific hand position for manual chest compression in adults. Computed tomography (CT) images of the chest can demonstrate objectively the spatial relationship between the surface landmarks on the chest and the inner viscera underneath them. This study is designed to examine the spatial relationship between the inter-nipple line (INL) and the heart in order to determine the proper hand position for more effective CPR.

METHODS

We enrolled 189 adult patients who underwent low dose chest CT from 16 October to 10 November 2006. Patients' demographic data were collected. The sternal length, the distance from the xiphoid to the INL, and the distance from the xiphoid to the maximal heart diameter were measured by using 3D reconstructed CT images.

RESULTS

In about 80% of the 189 patients' CT images, the intrathoracic structure just underneath the INL was the ascending aorta (18.0%), the root of aorta (48.7%), or the left ventricular outflow tract (12.7%), rather than the left ventricle itself (20.6%). The INL was 6.2+/-1.8cm and 5.6+/-1.9cm cephalad to the xiphoid for the male and the female, respectively. The coronal CT image plane of the maximal heart diameter was 2.8+/-1.6cm and 2.3+/-1.6cm cephalad to the xiphoid for the male and the female, respectively.

CONCLUSION

For more efficient and effective chest compression during CPR, compressing the sternum more caudally than the INL could be considered if it is not associated with the risk of increasing internal visceral injuries.

Quality of closed chest compression in ambulance vehicles, flying helicopters and at the scene

CONTEXT

Transport of patients during resuscitation is a critical procedure. In both, ambulances and helicopters the quality of resuscitation is potentially hampered due to the movement of the vehicle and confined space. To date, however, no direct comparison of the quality of resuscitation at the scene, during a helicopter flight and in a moving ambulance has been made.

OBJECTIVE

Direct comparison of the quality of resuscitation at the scene, during a helicopter flight and in a moving ambulance.

DESIGN

The study was performed in July 2005 as a randomised cross-over trial comparing different environments for resuscitation.

SETTING

Medical University of Vienna.

PARTICIPANTS

Eleven European Resuscitation Council (ERC) approved health care professionals.

INTERVENTIONS

Interventions during resuscitation: (a) in a moving ambulance, (b) in a flying helicopter, were compared to those staying at the (c) scene (control). Each participant performed resuscitation in all three environments.

MAIN OUTCOME MEASURES

Quality of chest compression during resuscitation.

RESULTS

Compared to resuscitation at the scene, efficiency of chest compressions during a helicopter flight was 86% and 95% in the moving ambulance 95%. There were no differences in secondary outcomes (time without chest compression, total number of incorrect hand position relative to total compressions, and total number of incorrect pressure release relative to total compressions).

CONCLUSIONS

Resuscitation during transport is feasible and relatively efficient. There is some difference between the environments, but there is no relevant difference between helicopters and ambulances regarding the effectiveness of CPR.

Haemodynamic effects of adrenaline (epinephrine) depend on chest compression quality during cardiopulmonary resuscitation in pigs

BACKGROUND

Adrenaline (epinephrine) is used during cardiopulmonary resuscitation (CPR) based on animal experiments without supportive clinical data. Clinically CPR was reported recently to have much poorer quality than expected from international guidelines and what is generally done in laboratory experiments. We have studied the haemodynamic effects of adrenaline during CPR with good laboratory quality and with quality simulating clinical findings and the feasibility of monitoring these effects through VF waveform analysis.

METHODS AND RESULTS

After 4 min of cardiac arrest, followed by 4 min of basic life support, 14 pigs were randomised to ClinicalCPR (intermittent manual chest compressions, compression-to-ventilation ratio 15:2, compression depth 30-38 mm) or LabCPR (continuous mechanical chest compressions, 12 ventilations/min, compression depth 45 mm). Adrenaline 0.02 mg/kg was administered 30 s thereafter. Plasma adrenaline concentration peaked earlier with LabCPR than with ClinicalCPR, median (range), 90 (30, 150) versus 150 (90, 270) s (p = 0.007), respectively. Coronary perfusion pressure (CPP) and cortical cerebral blood flow (CCBF) increased and femoral blood flow (FBF) decreased after adrenaline during LabCPR (mean differences (95% CI) CPP 17 (6, 29) mmHg (p = 0.01), FBF -5.0 (-8.8, -1.2) ml min(-1) (p = 0.02) and median difference CCBF 12% of baseline (p = 0.04)). There were no significant effects during ClinicalCPR (mean differences (95% CI) CPP 4.7 (-3.2, 13) mmHg (p = 0.2), FBF -0.2 (-4.6, 4.2) ml min(-1)(p = 0.9) and CCBF 3.6 (-1.8, 9.0)% of baseline (p = 0.15)). Slope VF waveform analysis reflected changes in CPP.

CONCLUSION

Adrenaline improved haemodynamics during laboratory quality CPR in pigs, but not with quality simulating clinically reported CPR performance.

Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: A prospective interventional study

AIMS

To compare quality of CPR during out-of-hospital cardiac arrest with and without automated feedback.

MATERIALS AND METHODS

Consecutive adult, out-of-hospital cardiac arrests of all causes were studied. One hundred and seventy-six episodes (March 2002-October 2003) without feedback were compared to 108 episodes (October 2003-September 2004) where automatic feedback on CPR was given. Automated verbal and visual feedback was based on measured quality with a prototype defibrillator. Quality of CPR was the main outcome measure and survival was reported as specified in the protocol.

RESULTS

Average compression depth increased from (mean +/- S.D.) 34 +/- 9 to 38 +/- 6 mm (mean difference (95% CI) 4 (2, 6), P < 0.001), and median percentage of compressions with adequate depth (38-51 mm) increased from 24% to 53% (P < 0.001, Mann-Whitney U-test) with feedback. Mean compression rate decreased from 121 +/- 18 to 109 +/- 12 min(-1) (difference -12 (-16, -9), P = 0.001). There were no changes in the mean number of ventilations per minute; 11 +/- 5 min(-1) versus 11 +/- 4 min(-1) (difference 0 (-1, 1), P = 0.8) or the fraction of time without chest compressions; 0.48 +/- 0.18 versus 0.45 +/- 0.17 (difference -0.03 (-0.08, 0.01), P = 0.08). With intention to treat analysis 7/241 control patients were discharged alive (2.9%) versus 5/117 with feedback (4.3%) (OR 1.5 (95% CI; 0.8, 3), P = 0.2). In a logistic regression analysis of all cases, witnessed arrest (OR 4.2 (95% CI; 1.6, 11), P = 0.004) and average compression depth (per mm increase) (OR 1.05 (95% CI; 1.01, 1.09), P = 0.02) were associated with rate of hospital admission.

CONCLUSIONS

Automatic feedback improved CPR quality in this prospective non-randomised study of out-of-hospital cardiac arrest. Increased compression depth was associated with increased short-term survival.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT00138996), http://www.clinicaltrials.gov/.

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

BACKGROUND

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.

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

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.

Unnecessary interruptions of cardiac massage during simulated cardiac arrests

BACKGROUND AND OBJECTIVE

Cardiopulmonary resuscitation should not be interrupted until the return of spontaneous circulation or the decision to withhold further treatment. There are no data on how consistent in-hospital cardiopulmonary resuscitation is performed. Accordingly, the aim of the present study was to identify length and type of unnecessary interruptions in simulated cardiac arrests.

METHODS

The study was carried out in a patient simulator. A scenario of cardiac arrest due to ventricular fibrillation was used. Resuscitation teams consisted of three nurses, a resident and a staff physician. Using videotapes recorded during simulations, the activities of the teams were coded in 5-s intervals. Unnecessary interruptions were defined as any interruptions in cardiac massage of 10 s or more that were not caused by defibrillation or endotracheal intubation.

RESULTS

Twelve teams were studied. The total time of possible cardiac massage was 414 +/- 125 s. In each team at least one unnecessary interruption occurred (range 1-5). Interruptions mounted up to 65 +/- 40 s (range 20-155) or 16 +/- 10% (range 5-41) of the total time of possible cardiac massage. Failure to swiftly resume cardiac massage after an unsuccessful defibrillation accounted for 14 of 39 episodes and for 44 +/- 40% of the time of unnecessary interruptions. The debriefings revealed that participants had generally not noticed the unnecessary interruptions during the simulation.

CONCLUSIONS

The present study identified a significant amount of unnecessary interruptions in cardiac massage. These interruptions were not noticed by the health-care workers involved.

[A portable sternal compressor for cardiac massage on a patient carried by a litter--Part 3: Applicability of the device tested by a recording manikin]

Effects of a portable sternal compressor developed by us was examined by 43 medical students (28 males and 15 females) and 9 anesthesia residents using a recording manikin. Compression over a depth of 3.5 to 5.0 cm was classified as adequate. First, the examinee held the device affixed in front of the chest with a belt hanged over the shoulder and pulled the other handle back and forth at a rate of 100 per minute. The male students could perform adequate compression in 92% of the total number of compression in the first one minute, while female students could in 65%. Though the anesthesia residents accomplished 99% of success rate in the first one minute, the rate fell to nearly 80% in the next minute and about 50% thereafter due to fatigue. When one handle was sustained on the floor with its fold-in stand and held between the knees of the examinee sitting on a chair, adequate compression was performed with the success rate of over 80% for 5 minutes. We conclude this device will be useful for cardiac massage on a patient either transported on a litter or lying on a soft bed.