To blow or not to blow: a randomised controlled trial of compression-only and standard telephone CPR instructions in simulated cardiac arrest

Drone-Facilitated Real-Time Video-Guided Feedback Helps to Improve the Quality of Lay Bystander Basic Life Support. A Randomized Controlled Simulation Trial

OBJECTIVES

Telephone instructions are commonly used to improve cardiopulmonary resuscitation (CPR) by lay bystanders. This usually implies an audio but no visual connection between the provider and the emergency medical telecommunicator. We aimed to investigate whether video-guided feedback via a camera drone enhances the quality of CPR.

METHODS

We conducted a randomized controlled simulation trial. Lay rescuers performed 8 min of CPR on an objective feedback manikin. Participants were randomized to receive telephone instructions with (intervention group) or without (control group) a drone providing a visual connection with the telecommunicator after a 2-min run-in phase. Performed work (total compression depth minus total lean depth) was the primary outcome. Secondary outcomes were the proportion of effective chest compressions, average compression depth, subjective physical strain measured every 2 min, and dexterity in the nine-hole peg test after the scenario. Outcomes were compared using the t- and Mann Whitney-U tests. A two-sided p-value of <0.05 was considered significant.

RESULTS

We included 27 individuals (14 (52%) female, mean age 41 ± 14 years). Performed work was greater in the intervention than in the control group (41.3 ± 7.0 vs. 33.9 ± 10.9 m; absolute difference 7.5, 95% CI 1.4 to 14.8; p = 0.046), with higher average compression depth (49 ± 7 vs. 40 ± 13 mm; p = 0.041), and higher proportions of adequate chest compressions (43 (IQR 14-60) vs. 3 (0-29) %; p = 0.041). We did not find any significant differences regarding the remaining secondary outcomes.

CONCLUSION

Video-guided feedback via drones might be a helpful tool to enhance the quality of telephone-assisted CPR in lay bystanders.

Knowledge and Attitudes around First Aid and Basic Life Support of Kindergarten and Elementary School Teachers and Parents in Taif City, Saudi Arabia

BACKGROUND

The foremost cause of children's (1-19 year) death is inadvertent injuries. While most of these accidental harms occur at home and school, rapid and suitable parental and teacher intervention is required to increase the chances of a child's survival. Therefore, both parents and teachers of the children in kindergarten and elementary school must be knowledgeable in first aid practice and basic life support (BLS) training.

OBJECTIVES

In the current study, our ambition is to evaluate the orientation level, knowledge, and attitudes around first aid and BLS training of kindergarten and elementary school teachers and parents in the city of Taif, Makkah region.

METHODS

A cross-sectional study in Taif, Saudi Arabia, targeted kindergarten and elementary school teachers and parents of students enrolled at these levels. There were 648 participants included in this study. The researchers assessed teachers' and parents' knowledge and attitudes around first aid and BLS using a validated, self-administered online questionnaire.

RESULTS

The study included 648 participants, including 248 (38.3%) teachers and 400 (61.7%) parents. The socio-demographic analysis showed that 412 (63.6%) are females and 233 (36.5%) are between the ages of 36 and 45 years. Approximately 142 (21.9%) participants reported previous training in the cardiopulmonary resuscitation (CPR) program, though more than half of them (53.5%) had outdated certificates (more than 2 years). The mean total knowledge for our study was 4.6 ± 1.4, with 22.4% of the participants being educated about first aid support and expressing a fair level of CPR foundations. Only a small percentage (2.3%) of the participants exposed a good and adequate theoretical level of knowledge around CPR skills and performance, while most of the contributors unveiled a poor level of knowledge (over 75%). There were no statistically significant differences between parents and teachers (p > 0.05). Finally, numerous participants (85%) appreciated training in the CPR program, and the most common motive was a "wish to avoid unnecessary death".

CONCLUSIONS

We concluded that a sizable portion of the contributors expressed a lack of proficiency in the fundamental CPR training knowledge and skills, pointing to an alarming public concern. Promisingly, a sizable percentage of participants expressed motivated attitudes toward CPR training. Therefore, additional study and data are required to effectively combat injury, with an emphasis on investigating causes and risk factors, burden and socioeconomic health determinants, community awareness level and desire to contribute, and accessibility for disseminating specific intervention strategies.

Using a filming protocol to improve video-instructed cardiopulmonary resuscitation

BACKGROUND:

Video communications during cardiopulmonary resuscitation (CPR) can improve the quality of information exchange between a bystander performing CPR and an emergency medical dispatcher (EMD).

OBJECTIVE:

To improve chest compression effectiveness, a filming protocol instructing video camera placements around a patient was developed. This study measured whether the filming protocol increased chest compressions’ effectiveness.

METHODS:

A simulation study was conducted comparing CPR effectiveness under three conditions: telephone-instructed, video-instructed, and video-instructed with the filming protocol. Twenty-five emergency medical technicians acted as EMDsin the three conditions. A mannequin measured five factors that determined the effectiveness of the chest compressions.

RESULTS:

Compared with telephone-instructed CPR, the filming protocol improved the proportion of time in which the bystander’s hands were in the correct position during chest compressions. Compared with video-instructed CPR, the filming protocol improved both the proportion of time in which the chest was fully released after each compression and the proportion of time in which the compressions were conducted with an appropriate rhythm. The depth and rate of compressions did not improve in the filming protocol condition.

CONCLUSIONS:

Video-instructed CPR with the filming protocol improves CPR effectiveness compared to telephone- and video-instructed CPR. Detailed implementation can improve new technology introduction.

Effects of dispatcher-initiated telephone cardiopulmonary resuscitation after out-of-hospital cardiac arrest: A nationwide, population-based, cohort study

AIM

This study aimed to investigate the effects of dispatcher-initiated telephone cardiopulmonary resuscitation (TCPR) in Japan using a nationwide population-based registry.

METHODS

Adult Japanese patients with out-of-hospital cardiac arrest (OHCA; n = 582,483, age ≥18 years) were selected from a nationwide Utstein-style database (2010-2016) and divided into 3 groups: no bystander CPR (NCPR) before emergency medical service arrival (n = 448,606), bystander-initiated CPR (BCPR) performed without assistance (n = 46,964), and TCPR (n = 86,913). The primary outcome was a favourable neurological outcome 1 month after OHCA.

RESULTS

After adjusting for potential confounders, and relative to the NCPR group, significantly better 1-month neurological outcomes were observed in the BCPR group (odds ratio: 2.25, 95% confidence interval: 2.15-2.36; P < 0.001) and in the TCPR group (odds ratio: 1.30, 95% confidence interval: 1.24-1.36; P < 0.001). The collapse-to-CPR time was independently associated with the 1-month outcomes, with a rate of <1% for 1-month favourable neurological outcomes if CPR was initiated >5 min after the collapse.

CONCLUSION

Patients who received TCPR had significantly better outcomes than those who did not receive CPR. However, the TCPR outcomes were less favourable than those in the BCPR group. Better protocol development and enhanced education are needed to improve dispatcher instructions in Japan, which may help lessen the gap between the BCPR and TCPR outcomes and further improve the outcomes after OHCA.

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

Background

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

Methods

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

Results

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

Conclusions

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

Safety and applicability of a pre-stage public access ventilator for trained laypersons: a proof of principle study

BACKGROUND

Contemporary resuscitation guidelines for basic life support recommend an immediate onset of cardiac compressions in case of cardiac arrest followed by rescue breaths. Effective ventilation is often omitted due to fear of doing harm and fear of infectious diseases. In order to improve ventilation a pre-stage of an automatic respirator was developed for use by laypersons.

METHODS

Fifty-two healthy volunteers were ventilated by means of a prototype respirator via a full-face mask in a pilot study. The pre-stage public access ventilator (PAV) consisted of a low-cost self-designed turbine, with sensors for differential pressure, flow, FO₂, FCO₂ and 3-axis acceleration measurement. Sensor outputs were used to control the respirator and to recognize conditions relevant for efficiency of ventilation and patients' safety. Different respiratory manoeuvres were applied: a) pressure controlled ventilation (PCV), b) PCV with controlled leakage and c) PCV with simulated airway occlusion. Sensor signals were analysed to detect leakage and airway occlusion. Detection based upon sensor signals was compared with evaluation based on clinical observation and additional parameters such as exhaled CO₂.

RESULTS

Pressure controlled ventilation could be realized in all volunteers. Leakage was recognized with 93.5% sensitivity and 93.5% specificity. Simulated airway occlusion was detected with 91.8% sensitivity and 91.7% specificity.

CONCLUSION

The pre-stage PAV was able to detect potential complications relevant for patients' safety such as leakage and airway occlusion in a proof of principle study. Prospectively, this device provides a respectable basis for the development of an automatic emergency respirator and may help to improve bystander resuscitation.

Systematic review of the mechanisms driving effective blood flow during adult CPR

BACKGROUND

High quality chest compressions is the most significant factor related to improved short-term and long-term outcome in cardiac arrest. However, considerable controversy exists over the mechanisms involved in driving blood flow.

OBJECTIVES

The aim of this systematic review is to elucidate major mechanisms involved in effective compression-mediated blood flow during adult cardiopulmonary resuscitation (CPR).

DESIGN AND SETTING

Systematic review of studies identified from the bibliographic databases of PubMed/Medline, Cochrane, and Scopus.

SELECTION CRITERIA

All human and animal studies including information on the responsible mechanisms of compression-related blood flow.

DATA COLLECTION AND ANALYSIS

Two reviewers (MG, TX) independently screened all potentially relevant titles and abstracts for eligibility, by using a standardized data-worksheet.

MAIN RESULTS

Forty seven studies met the inclusion criteria. Because of the heterogeneity in outcome measures, quantitative synthesis of evidence was not feasible. Evidence was critically synthesized in order to answer the review questions, taking into account study heterogeneity and validity. The number of included studies per category is as follows: blood flow during chest compression, nine studies; blood flow during chest decompression, six studies; effect of chest compression on cerebral blood flow, eight studies; active compression-decompression CPR, 14 studies; and effect of ventilation on compression-related blood flow, 13 studies.

CONCLUSION

The evidence so far is inconclusive regarding the major responsible mechanism in compression-related blood flow. Although both 'cardiac pump' and 'thoracic pump' have a key role, the effect of each mechanism is highly depended on other resuscitation parameters, such as positive pressure ventilation and compression depth.

Effects of repetitive or intensified instructions in telephone assisted, bystander cardiopulmonary resuscitation: an investigator-blinded, 4-armed, randomized, factorial simulation trial

BACKGROUND

Compression depth is frequently suboptimal in cardiopulmonary resuscitation (CPR). We investigated effects of intensified wording and/or repetitive target depth instructions on compression depth in telephone-assisted, protocol driven, bystander CPR on a simulation manikin.

METHODS

Thirty-two volunteers performed 10 min of compression only-CPR in a prospective, investigator-blinded, 4-armed, factorial setting. Participants were randomized either to standard wording ("push down firmly 5 cm"), intensified wording ("it is very important to push down 5 cm every time") or standard or intensified wording repeated every 20s. Three dispatchers were randomized to give these instructions. Primary outcome was relative compression depth (absolute compression depth minus leaning depth). Secondary outcomes were absolute distance, hands-off times as well as BORG-scale and nine-hole peg test (NHPT), pulse rate and blood pressure to reflect physical exertion. We applied a random effects linear regression model.

RESULTS

Relative compression depth was 35 ± 10 mm (standard) versus 31 ± 11 mm (intensified wording) versus 25 ± 8 mm (repeated standard) and 31 ± 14 mm (repeated intensified wording). Adjusted for design, body mass index and female sex, intensified wording and repetition led to decreased compression depth of 13 (95%CI -25 to -1) mm (p=0.04) and 9 (95%CI -21 to 3) mm (p=0.13), respectively. Secondary outcomes regarding intensified wording showed significant differences for absolute distance (43 ± 2 versus 20 (95%CI 3-37) mm; p=0.01) and hands-off times (60 ± 40 versus 157 (95%CI 63-251) s; p=0.04).

CONCLUSION

In protocol driven, telephone-assisted, bystander CPR, intensified wording and/or repetitive target depth instruction will not improve compression depth compared to the standard instruction.

New pre-arrival instructions can avoid abdominal hand placement for chest compressions

OBJECTIVE

To investigate if modified pre-arrival instructions using patient's arm and nipple line as landmarks could avoid abdominal hand placements for chest compressions.

METHOD

Volunteers were randomized to one of two telephone instructions: "Kneel down beside the chest. Place one hand in the centre of the victim's chest and the other on top" (control) or "Lay the patient's arm which is closest to you, straight out from the body. Kneel down by the patient and place one knee on each side of the arm. Find the midpoint between the nipples and place your hands on top of each other" (intervention). Hand placement was conducted on an adult male and documented by laser measurements. Hand placement, quantified as the centre of the compressing hands in the mid-sagittal plane, was compared to the inter-nipple line (INL) for reference and classified as above or below. Fisher's exact test was used for comparison of proportions.

RESULTS

Thirty-six lay people, age range 16-60, were included. None in the intervention group placed their hands in the abdominal region, compared to 5/18 in the control group (p = 0.045). Using INL as a reference, the new instructions resulted in less caudal hand placement, and the difference in mean hand position was 47 mm [95% CI 21,73], p = 0.001.

CONCLUSION

New pre-arrival instructions where the patient's arm and nipple line were used as landmarks resulted in less caudal hand placements and none in the abdominal region.

Time to first compression using Medical Priority Dispatch System compression-first dispatcher-assisted cardiopulmonary resuscitation protocols

INTRODUCTION

Without bystander cardiopulmonary resuscitation (CPR), cardiac arrest survival decreases 7%-10% for every minute of delay until defibrillation. Dispatcher-assisted CPR (D-CPR) has been shown to increase the rates of bystander CPR and cardiac arrest survival. Other reports suggest that the most critical component of bystander CPR is chest compressions with minimal interruption. Beginning with version 11.2 of the Medical Priority Dispatch System (MPDS) protocols, instructions for mouth-to-mouth ventilation (MTMV) and pulse check were removed and a compression-first pathway was introduced to facilitate rapid delivery of compressions. Additionally, unconscious choking and third-trimester pregnancy decision-making criteria were added in versions 11.3 and 12.0, respectively. However, the effects of these changes on time to first compression (TTFC) have not been evaluated.

OBJECTIVE

We sought to quantify the TTFC of MPDS versions 11.2, 11.3, and 12.0 for all calls identified as cardiac arrest on call intake that did not require MTMV instruction.

METHODS

Audio recordings of all D-CPR events for October 2005 through May 2010 were analyzed for TTFC. Differences in TTFC across versions were compared using the Kruskal-Wallis test.

RESULTS

A total of 778 cases received D-CPR. Of these, 259 were excluded because they met criteria for MTMV (pediatric patients, allergic reaction, etc.), were missing data, or were not initially identified as cardiac arrest. Of the remaining 519 calls, the mean TTFC was 240 seconds, with no significant variation across the MPDS versions (p = 0.08).

CONCLUSIONS

Following the removal of instructions for pulse check and MTMV, as well as other minor changes in the MPDS protocols, we found the overall TTFC to be 240 seconds with little variation across the three versions evaluated. This represents an improvement in TTFC compared with reports of an earlier version of MPDS that included pulse checks and MTMV instructions (315 seconds). However, the MPDS TTFC does not compare favorably with reports of older, non-MPDS protocols that included pulse checks and MTMV. Efforts should continue to focus on improving this key, and modifiable, determinant of cardiac arrest survival.

Dispatcher-assisted telephone cardiopulmonary resuscitation using a French-language compression-only protocol in volunteers with or without prior life support training: A randomized trial

OBJECTIVES

Due to the recent interest in hands-only protocols for dispatcher-assisted cardiopulmonary resuscitation (CPR) and the lack of any validated algorithms in French, our primary objective was to evaluate a new French-language protocol in terms of its efficacy to help previously untrained volunteers in performing basic life support efforts of appropriate quality, and secondarily to investigate its potential utility in subjects with previous training.

METHODS

Untrained volunteers were recruited among adults in a public movie centre and previously trained volunteers among undergraduate nursing students. Participants were randomly assigned to 'phone CPR' versus 'no phone CPR' by drawing sets of envelopes. Primary outcome measures were the results of the Cardiff evaluation test; the secondary measures were global scoring of a complete 5min period of CPR, in a manikin model of cardiac arrest.

RESULTS

Out of 146 volunteers assessed for eligibility, 36 previously untrained candidates declined participation. 110 participants, distributed into four groups, completed the study: the previously untrained non-guided group (group A, n=30), the previously untrained guided group (group B, n=30), the previously trained non-guided group (group C, n=25) and the previously trained guided group (group D, n=25). Results of the Cardiff test and global evaluation of CPR performance revealed a significant improvement in group B as compared with group A, approaching the level of the group C. Previously trained guided bystanders had the best CPR scores, notably because of an improvement in the quality of airway management.

CONCLUSION

When used by dispatchers, this new French-language algorithm offers the opportunity to help previously untrained bystanders initiate CPR. The same protocol may serve to guide volunteers with prior basic life support training to reach their best CPR performance.

Effect of listening to Nellie the Elephant during CPR training on performance of chest compressions by lay people: randomised crossover trial

OBJECTIVES

To determine whether listening to music during cardiopulmonary resuscitation (CPR) training increases the proportion of lay people delivering chest compressions of 100 per minute.

DESIGN

Prospective randomised crossover trial.

SETTING

Large UK university.

PARTICIPANTS

130 volunteers (81 men) recruited on an opportunistic basis. Exclusion criteria included age under 18, trained health professionals, and cardiopulmonary resuscitation (CPR) training within the past three months.

INTERVENTIONS

Volunteers performed three sequences of one minute of continuous chest compressions on a skill meter resuscitation manikin accompanied by no music, repeated choruses of Nellie the Elephant (Nellie), and That's the Way (I like it) (TTW) according to a pre-randomised order.

MAIN OUTCOME MEASURES

Rate of chest compressions delivered (primary outcome), depth of compressions, proportion of incorrect compressions, and type of error.

RESULTS

Median (interquartile range) compression rates were 110 (93-119) with no music, 105 (98-107) with Nellie, and 109 (103-110) with TTW. There were significant differences within groups between Nellie v no music and Nellie v TTW (P<0.001) but not no music v TTW (P=0.055). A compression rate of between 95 and 105 was achieved with no music, Nellie, and TTW for 15/130 (12%), 42/130 (32%), and 12/130 (9%) attempts, respectively. Differences in proportions were significant for Nellie v no music and Nellie v TTW (P<0.001) but not for no music v TTW (P=0.55). Relative risk for a compression rate between 95 and 105 was 2.8 (95% confidence interval 1.66 to 4.80) for Nellie v no music, 0.8 (0.40 to 1.62) for TTW v no music, and 3.5 (1.97 to 6.33) for Nellie v TTW. The number needed to treat for listening to Nellie v no music was 5 (4 to 10)-that is, the number of cardiac arrests required during which lay responders listen to Nellie to facilitate one patient receiving compressions at the correct rate (v no music) would be between four and 10. A greater proportion of compressions were too shallow when participants listened to Nellie v no music (56% v 47%, P=0.022).

CONCLUSIONS

Listening to Nellie the Elephant significantly increased the proportion of lay people delivering compression rates at close to 100 per minute. Unfortunately it also increased the proportion of compressions delivered at an inadequate depth. As current resuscitation guidelines give equal emphasis to correct rate and depth, listening to Nellie the Elephant as a learning aid during CPR training should be discontinued. Further research is required to identify music that, when played during CPR training, increases the proportion of lay responders providing chest compressions at both the correct rate and depth.

Knowledge and attitudes towards cardiopulmonary resuscitation and defibrillation amongst Asian primary health care physicians

Objective

To assess the knowledge and attitudes of local primary health care physicians in relation to cardiopulmonary resuscitation (CPR) and defibrillation.

Methods

We conducted a survey on general practitioners in Singapore by using a self-administered questionnaire that comprised 29 questions.

Results

The response rate was 80%, with 60 of 75 physicians completing the questionnaire. The average age of the respondents was 52 years. Sixty percent of them reported that they knew how to operate an automated external defibrillator (AED), and 38% had attended AED training. Only 36% were willing to perform mouth-to-mouth ventilation during CPR, and 53% preferred chest compression-only resuscitation (CCR) to standard CPR. We found those aged <50 years were more likely to be trained in basic cardiac life support (BCLS) (P < 0.001) and advanced cardiac life support (P = 0.005) or to have ever attended to a patient with cardiac arrest (P = 0.007). Female physicians tended to agree that all clinics should have AEDs (P = 0.005) and support legislation to make AEDs compulsory in clinics (P < 0.001). We also found that a large proportion of physicians who were trained in BCLS (P = 0.006) were willing to perform mouth-to-mouth ventilation.

Conclusion

Most local primary care physicians realize the importance of defibrillation, and the majority prefer CCR to standard CPR.

Skill acquisition by health care workers in the Resuscitation Council (UK) 2005 Guidelines for Adult Basic Life Support

This prospective study compared pre- and post-class performance in basic life support (BLS) on a recording manikin in a convenience sample of 34 health care workers undertaking a two-hour class provided by a hospital resuscitation department teaching the 2005 Resuscitation Council (UK) guidelines. On completion of training there were significant improvements in the proportion of subjects correctly performing a safe approach (14/34 vs. 25/33, 95%CI +11 to +55%, p=0.004), checking for response (17/34 vs. 24/32, 95%CI +1 to +46%, p=0.029), shouting for help (18/34 vs. 28/32, 95%CI +13 to +54%, p=0.002), opening the airway (6/34 vs. 26/32, 95%CI +42 to +79%, p<0.001), checking for breathing (9/34 vs. 27/32, 95%CI +35 to +74%, p<0.001), calling a cardiac arrest team (1/34 vs. 24/32, 95%CI +53 to +85%, p<0.001), and providing the correct compression to breath ratio (11/34 vs. 20/34, +3 to +48%, p=0.033). The median number of correct chest compressions increased from 3 to 41 (p<0.001) with improvements in adequate depth (median depth 36 vs. 40mm, p=0.006), although the compression rate was too fast before training and increased afterwards (median 123 vs. 147, p<0.001). Ventilation performance could not be measured accurately as the manikin was calibrated incorrectly by the manufacturers.

A Simulation Trial of Traditional Dispatcher-Assisted CPR Versus Compressions—Only Dispatcher-Assisted CPR

OBJECTIVES

Growing evidence indicates that it may not be essential to deliver ventilations in the first few minutes of CPR. We compared time to delivery of first compression in traditional CPR with ventilations and compressions to compression-only CPR performed by untrained laypersons assisted by a mock 911 dispatcher.

METHODS

This randomized-controlled simulation study included a convenience sample of English-speaking emergency department visitors during a 6-month period. Exclusion criteria were prior CPR training or physical incapacity. A cardiac arrest scenario was presented to subjects who were then provided with one of two sets of telephone CPR instructions by a mock 911 dispatcher. One group received traditional CPR instructions (TCPR) and the second group received compression only CPR instructions (COCPR). Subjects performed CPR on a Laerdal Resusci-Anne CPR manikin and recording strips were analyzed for frequency and quality measures. Pre-and post-test questionnaires assessed subject fatigue and telephone instruction understanding. The primary outcome was the time interval from 911 call to initiation of chest compressions. Analysis included Student t-test, Chi-square, and Wilcoxon Rank Sum.

RESULTS

Of 377 potential subjects, 54 consented to randomization. The data from 50 subjects were analyzed. Compared to group TCPR, group COCPR initiated chest compressions faster (72 vs 117 sec, p < 0.0001), completed four cycles of CPR faster (168 vs. 250 sec, p < 0.0001), and paused for a smaller percentage of the resuscitation (13% vs. 36%, p < 0.0001). Only 9% of ventilation opportunities in the TCPR group yielded ventilations of the correct volume. There were no differences between groups in perceived understanding of CPR instruction or fatigue.

CONCLUSIONS

We have identified the potential timesavings that may occur during compressions-only CPR. Bystander resuscitation may be more efficient when ventilations are excluded from the CPR sequence.

Interactive video instruction improves the quality of dispatcher-assisted chest compression-only cardiopulmonary resuscitation in simulated cardiac arrests

OBJECTIVE

Bystander cardiopulmonary resuscitation (CPR) significantly improves survival of cardiac arrest victims. Dispatch assistance increases bystander CPR, but the quality of dispatcher-assisted CPR remains unsatisfactory. This study was conducted to assess the effect of adding interactive video communication to dispatch instruction on the quality of bystander chest compressions in simulated cardiac arrests.

DESIGN

A randomized controlled study with a scenario developed to simulate cardiac arrest in a public place.

SETTING

The victim was simulated by a mannequin and the cell phone for dispatch assistance was a video cell phone with both voice and video modes. Chest compression-only CPR instruction was used in the dispatch protocol.

SUBJECTS

Ninety-six adults without CPR training within 5 years were recruited.

INTERVENTIONS

The subjects were randomized to receive dispatch assistance on chest compression with either voice instruction alone (voice group, n = 53) or interactive voice and video demonstration and feedback (video group, n = 43) via a video cell phone.

MEASUREMENTS AND MAIN RESULTS

Performance of chest compression-only CPR throughout the scenario was videotaped. The quality of CPR was evaluated by reviewing the videos and mannequin reports. Chest compressions among the video group were faster (median rate 95.5 vs. 63.0 min-1, p < 0.01), deeper (median depth 36.0 vs. 25.0 mm, p < 0.01), and of more appropriate depth (20.0% vs. 0%, p < 0.01). The video group had more "hands-off" time (5.0 vs. 0 second, p < 0.01), longer time to first chest compression (145.0 vs. 116.0 seconds, p < 0.01) and total instruction time (150.0 vs. 121.0 seconds, p < 0.01).

CONCLUSION

The addition of interactive video communication to dispatcher-assisted chest compression-only CPR initially delayed the commencement of chest compressions, but subsequently improved the depth and rate of compressions. The benefit was achieved mainly through real-time feedback.

Defibrillation and the quality of layperson cardiopulmonary resuscitation-dispatcher assistance or training?

AIMS OF THE STUDY

To examine whether basic life support-defibrillation (BLS-D) training of laypersons enhances the speed of defibrillation and the quality of cardiopulmonary resuscitation (CPR) during a simulated ventricular fibrillation scenario compared with a situation where the care provider has no previous BLS-D training but receives dispatcher assistance with the use of an automated external defibrillator (AED) and the performance of CPR.

METHODS

Fifty-two military conscripts of the Finnish Defence Forces who without previous medical education had been tested in a simulated cardiac arrest scenario with dispatcher assistance and thereafter received a 4-h BLS-D training. Six months later they were randomly divided to form teams of two and again tested in a similar scenario but without dispatcher assistance. The time interval from collapse to first shock, hands-off time and the quality of CPR were compared between the two tests.

RESULTS

The quality of mouth-to-mouth ventilation was better after training, but there was only a minor improvement in the quality of compressions and the speed of defibrillation.

CONCLUSIONS

Training improved the quality of mouth-to-mouth ventilation performed by laypersons but had only a minor effect on defibrillation and the quality of compressions.

To see or not to see--better dispatcher-assisted CPR with video-calls? A qualitative study based on simulated trials

BACKGROUND

Video communication through mobile telephone is now available in many parts of the world. We ask how mobile phone video-calls compares with traditional phone calls for dispatcher-assisted cardiopulmonary resuscitation (T-CPR).

METHODS

Primary data was collected through individual interviews with six dispatchers after their participation in simulated cardiac arrest. They had 10 scenarios each, during which they guided rescuers on resuscitation. During half of the scenarios they used video-calls, and traditional phone calls for the rest. Concepts from modern systems theory were used to analyse the material.

RESULTS

Video-calls influenced the information basis and understanding of the dispatchers. The dispatchers experienced that (1) video-calls are useful for obtaining information and provides adequate functionality to support CPR assistance; (2) their CPR assistance becomes easier; (3) the CPR might be of better quality; but (4) there is a risk of "noise".

DISCUSSION

We emphasize visual observation as a way of constructing professional understanding when using video-calls, which may provide a new basis for dispatcher assistance. Video-calls may improve rescuer compliance. The role and content of telephone-directed protocols used by dispatchers may need adjustments when video-calls are used for medical emergencies.

CONCLUSION

Video communication can improve the dispatchers' understanding of the rescuer's situation, and the assistance they provide.

Impact of adding video communication to dispatch instructions on the quality of rescue breathing in simulated cardiac arrests--a randomized controlled study

OBJECTIVE

Both ventilations and compressions are important for victims of prolonged cardiopulmonary resuscitation (CPR) and asphyxial arrest. Dispatch assistance increases bystander CPR, but the quality of dispatcher-assisted CPR (DA-CPR), especially rescue breathing, remains unsatisfactory. This study was conducted to assess the impact of adding interactive video communication to dispatch instructions on the quality of rescue breathing in simulated cardiac arrests.

METHODS

In this simulation-based study, adults without CPR training within 5 years were recruited between April and July 2007 and randomized to receive dispatch assistance with either voice instruction alone (voice group, n=53) or interactive voice and video instruction (video group, n=43) via a video cell phone. The quality of rescue breathing was evaluated by reviewing the videos and mannequin reports.

RESULTS

Subjects in the video group were more likely to open the airway correctly (95.3% vs. 58.5%, P<0.01) and to lift the chin properly (95.3% vs. 62.3%, P<0.01), but had similar rates of head-tilt (95.3% vs. 84.9%, P=0.10). Volunteers in the video group had larger volume of ventilation (median volume 540 ml vs. 0 ml, P<0.01), greater possibility to sustain an open airway (88.4% vs. 60.4%, P<0.01) and a tendency towards better nose-pinch (97.7% vs. 86.8%, P=0.06). The video group spent longer time to open the airway (59 s vs. 56 s, P<0.05) and to give the first rescue breathing (139 s vs. 102 s, P<0.01).

CONCLUSION

Adding video communication to dispatch instructions improved the quality of bystander rescue breathing, including higher proportion of airway opened, and larger volume of ventilation delivered, in simulated cardiac arrests.

Comparison of chest compression only and standard cardiopulmonary resuscitation for out-of-hospital cardiac arrest in Singapore

OBJECTIVE

Chest compression only cardiopulmonary resuscitation (CC-CPR) without ventilation has been proposed as an alternative to standard cardiopulmonary resuscitation (CPR) for bystanders. However, there has been controversy regarding the relative effectiveness of both of these techniques. We aim to compare the outcomes of cardiac arrest patients in the cardiac arrest and resuscitation epidemiology study who either received CC-CPR, standard CPR or no bystander CPR.

METHODS

This prospective cohort study involved all out-of-hospital cardiac arrest (OHCA) patients attended to by emergency medical service (EMS) providers in a large urban centre. The data analyses were conducted secondarily on these collected data. The technique of bystander CPR was reported by paramedics who arrived at the scene.

RESULTS

From 1 October 2001 to 14 October 2004, 2428 patients were enrolled into the study. Of these, 255 were EMS-witnessed arrests and were excluded. 1695 cases did not receive any bystander CPR, 287 had standard CPR and 154 CC-CPR. Patient characteristics were similar in both the standard and CC-CPR groups except for a higher incidence of residential arrests and previous heart disease sufferers in the CC-CPR group. Patients who received standard CPR (odds ratio (OR) 5.4, 95% confidence interval (CI) 2.1-14.0) or CC-CPR (OR 5.0, 95% CI 1.5-16.4) were more likely to survive to discharge than those who had no bystander CPR. There was no significant difference in survival to discharge between those who received CC-CPR and standard CPR (OR 0.9, 95% CI 0.3-3.1).

CONCLUSION

We found that patients were more likely to survive with any form of bystander CPR than without. This emphasises the importance of chest compressions for OHCA patients, whether with or without ventilation.

At what age can schoolchildren provide effective chest compressions? An observational study from the Heartstart UK schools training programme

OBJECTIVE

To determine at what age children can perform effective chest compressions for cardiopulmonary resuscitation.

DESIGN

Observational study.

SETTING

Four schools in Cardiff.

PARTICIPANTS

157 children aged 9-14 years in three school year groups (ages 9-10, 11-12, and 13-14).

INTERVENTIONS

Participants were taught basic life support skills in one lesson lasting 20 minutes.

MAIN OUTCOME MEASURE

Effectiveness of chest compression during three minutes' continuous chest compression on a manikin.

RESULTS

No year 5 pupil (age 9-10) was able to compress the manikin's chest to the depth recommended in guidelines (38-51 mm). 19% of pupils in year 7 (age 11-12) and 45% in year 9 (age 13-14) achieved adequate compression depth. Only the 13-14 year olds performed chest compression as well as adults in other reported studies. Compression depth showed a significant relation with children's age, weight, and height (P<0.001). Multivariate analyses showed that, if the age and weight of the children were both known, the height (which is closely related to both) was no longer significant (P=0.95). No association was found between pupils' age, sex, weight, or height and the average rate of chest compressions over the three minute period. Similarly, no relation was found between year group and ability to place the hands in the correct position. During the three minutes' compression, compression rate increased and depth decreased.

CONCLUSIONS

The children's ability to achieve an adequate depth of chest compression depended on their age and weight. The ability to provide the correct rate and to employ the correct hand position was similar across all the age ranges tested. Young children who are not yet physically able to compress the chest can learn the principles of chest compression as well as older children.

Methods of assessing cardiopulmonary resuscitation skills: a systematic review

Valid and reliable instruments are needed for assessment and comparison of training outcomes after various methods of cardiopulmonary resuscitation training. Trials were retrieved by searching MEDLINE (1990-February 2005) and using the reference lists of original communications and reviews. Studies were considered relevant if they included an intervention, a study population of life support providers randomized and divided into groups and an evaluation or assessment of the performance. The studies were analyzed and scored to assess their validity. Twenty-five studies fulfilled the criteria. Nineteen of them assessed cardiopulmonary resuscitation skills, four cardiopulmonary resuscitation and defibrillation and two assessed defibrillation only. The mean number of participants was 107 (range 36-495). A wide variety of assessment methods were used in the studies with methodological shortcomings. Most studies in this review compared participants with each other, not against a standard or a defined passing level. Qualified studies with well defined study populations, standardized study settings and explicit, comparable outcomes would be needed to assess the quality of cardiopulmonary resuscitation and defibrillation performance.

A prospective manikin-based observational study of telephone-directed cardiopulmonary resuscitation

INTRODUCTION

Bystander cardiopulmonary resuscitation (CPR) significantly improves the outcome from sudden cardiac arrest (SCA) and is therefore encouraged by offering telephone instructions to the bystander. The effectiveness of this technique was examined in a manikin-based study.

METHODS

Subjects performed CPR on an instrumented adult manikin by following Advanced Medical Priority Dispatch System v11.1 (AMPDS) instructions given by telephone from a different room.

RESULTS

Fifty-one volunteers (26 males, median age 56, range 27-76 years) with no previous experience of CPR were recruited. No volunteers followed the entire instructions correctly. Forty percent were unable to open the airway, only 18% achieved a median inspiration time of 2 s or greater and only 30% delivered tidal volumes within the range 700-1000 ml. Chest compressions were performed at a median rate of 52 min-1 with only 4% of subjects achieving a rate of 100 min-1. Depth of compression was also inadequate in 88% of subjects and hand positioning was incorrect in a third of subjects. The median duty cycle was 46% and there were significant delays between the commencement of the AMPDS protocol and the delivery of the first breath (123 s) and first chest compression (163 s).

DISCUSSION

Few bystanders perform CPR satisfactorily and further work is necessary to improve the effectiveness of telephone CPR instructions.

Assessment of the quality of cardiopulmonary resuscitation following modification of a standard telephone-directed protocol

INTRODUCTION

Current Advanced Medical Priority Dispatch System (AMPDS) V.11.1 telephone instructions are limited in their ability to produce correctly performed basic life support. The current telephone instructions were modified in an attempt to improve areas of poor CPR performance.

METHODS

Fifty subjects performed CPR on an instrumented adult manikin by following instructions modified from AMPDS V.11.1 instructions. Instructions were given by telephone from a different room.

RESULTS

No improvements were seen with opening the airway or delivering rescue breaths. The rate of chest compression improved from 52 to 81 min-1 (P=0.004), although the depth of chest compression fell to 2.0 cm compared with 3.2 cm documented with the original AMPDS instructions (P=0.004). Instructions to put the telephone down while performing CPR improved all aspects of CPR.

DISCUSSION

The effective delivery of telephone-directed CPR to untrained bystanders is a complex process. Changing verbal instructions to improve the quality of CPR is not easy. Further work is urgently needed to strengthen this important link in the chain of survival.

Haemodynamics of cardiac arrest and resuscitation

PURPOSE OF REVIEW

This review will summarize the available data regarding the haemodynamic changes occurring following cardiac arrest in humans and animal models.

RECENT FINDINGS

Following cardiac arrest due to ventricular fibrillation without cardiopulmonary resuscitation, blood flow exponentially falls but continues for approximately 5 min until the pressure gradient between the aorta and the right heart is completely dissipated. During cardiopulmonary resuscitation forward flow occurs into the aorta during the compression phase. Coronary blood flow is retrograde during the compression phase and antegrade during the decompression phase. Carotid blood flow takes over a minute to reach plateau levels following the initiation of chest compressions, and even brief interruptions of compressions result in a dramatic reduction in carotid blood flow which takes a minute or so to recover to plateau levels when compressions are reinstituted. Coronary perfusion pressure during the release phase of cardiopulmonary resuscitation has been shown to be a powerful predictor of the likelihood of recovery of spontaneous circulation following restoration of electrical activity.

SUMMARY

Recent studies have provided important insights into the haemodynamics of cardiac arrest and of cardiopulmonary resuscitation which may inform more effective strategies for the management of cardiac arrest in the future.

Are the new resuscitation guidelines optimal?

PURPOSE OF REVIEW

The purpose of this review is to evaluate the 2005 guidelines on cardiopulmonary resuscitation.

RECENT FINDINGS

International guidelines are based ideally on results from robust clinical trials. They are necessarily constrained in how far they can draw conclusions from experimental data, and have to pay regard to perceived safety and educational issues. Informed opinion can be more radical in drawing from compelling recent experimental findings, particularly when supported by unreplicated or indirect clinical evidence. Those already available cover a range of issues relevant to the guidelines; the most important ones are reviewed here.

SUMMARY

The 2005 guidelines represent a major advance on those previously in use, but on the evidence already available they cannot be considered optimal. Deviations based on good evidence should not be discouraged provided they are approved and preferably monitored by authoritative bodies that should see this as a legitimate role in developing the science of resuscitation medicine. Guidelines for the most pressing of medical emergencies should not be set and inflexible over several years whilst the science behind them continues to advance.

Modified cardiopulmonary resuscitation (CPR) instruction protocols for emergency medical dispatchers: rationale and recommendations

BACKGROUND

International consensus guidelines now support the use of "chest compressions-only" cardiopulmonary resuscitation (CPR) instructions (CCOIs) by emergency medical dispatch (EMD) personnel providing telephone assistance to untrained bystanders at a cardiac arrest scene. These guidelines are based largely on evolving experimental data and a clinical trial conducted in one venue with distinct emergency medical services (EMS) system features. Accordingly, the Council of Standards for the National Academies of Emergency Dispatch was asked to adapt a modified telephone CPR protocol, and specifically one that could be applied more broadly to the spectrum of EMS systems.

METHODS

A group of international EMD specialists, researchers and professional association representatives analyzed available scientific data and considered variations in EMS systems, particularly those in Europe and North America.

RESULTS AND CONCLUSIONS

Several recommendations were established: (1) to avoid confusion, bystanders already providing CPR should continue those previously learned methods; (2) following a sudden collapse unlikely to be of respiratory etiology, CCOIs should be provided when the bystander is not CPR-trained, declining to perform mouth-to-mouth ventilation or unsure of actions to take; (3) following 4 min of CCOIs, ventilations can be provided, but, for now, only at a compression-ventilation ratio of 100:2 until EMS arrives; (4) until more data become available, dispatchers should follow existing compression-ventilation protocols for children and adult cases involving probable respiratory/trauma etiologies; (5) EMD CPR protocols should account for EMS system features and receive quality oversight and expert medical direction.