Tonje S. Birkenes

Video analysis of dispatcher–rescuer teamwork–Effects on CPR technique and performance

OBJECTIVE We wanted to study the effect of continuous dispatcher communication on CPR technique and performance during 10min of simulated cardiac arrest. METHOD We reviewed video recordings and manikin data from 30 CPR trained lay people who where left alone in a simulated cardiac arrest situation with a manikin in a home-like environment (in a small, confined kitchen with the disturbing noise of a radio). CPR was performed for 10min with continuous telephone instructions via speaker function from a dispatcher. The dispatcher was blinded for CPR performance and video. Dispatcher communication, compression technique and ventilation technique was scored as accomplished or failed in the 1st and 10th minute. RESULTS 29/30 rescuers were able to hear instructions, answer questions from the dispatcher and perform CPR in parallel. Rescuer position beside manikin was initially correct for 13/30, improving to 21/30 (p=0.008). Compression technique was adequate for the whole episode, with an insignificant trend for improvement; 29 to 30/30 using straight arms, 28 to 30/30 in a vertical position over chest and 24 to 27/30 counting loudly. 17/29 placed their hands between the nipples initially, improving to 24/29 (p=0.065). Mean compression rate improved from 84 to 101min(-1) (p<0.001), and compression depth maintained adequate (43 to 42mm). Initially, 17/29 used chin-lift manoeuvre, 14/30 used head-tilt and 19/29 used nose pinch to manage open airways, compared to 18, 20 and 22/29 (ns) in the 10th minute, respectively. Successful delivery of ventilation improved from 13/30 to 23/30 (p=0.006). CONCLUSION Bystander and dispatcher can communicate successfully during ongoing CPR using a telephone with speaker function. CPR technique and quality improved or did not change over 10min with continuous dispatcher assistance. These results suggest a potential for improved bystander CPR using rescuer-dispatcher teamwork.

A randomized trial of the capability of elderly lay persons to perform chest compression only CPR versus standard 30:2 CPR

AIM OF THE STUDY Early cardiopulmonary resuscitation (CPR) improves survival after cardiac arrest, but there is a discrepancy between the age group normally attending CPR-classes and the age group most likely to witness a cardiac arrest. We wanted to study if elderly lay persons could perform 10min of CPR on a realistic manikin with continuous chest compressions (CCC) and conventional CPR (30:2). METHODS Volunteers were tested 5-7 months after CPR-classes. They were randomized to CCC or 30:2, and to receive feedback (FB) or not. Quality of CPR, age adjusted maximum heart rate (HRmax), and subjective exhaustion ratings were measured and evaluated in a blinded fashion. Temporal development and group differences were evaluated with ANOVA procedures. RESULTS All 64 volunteers were able to perform CPR for 10min and rated their efforts as mild to moderate in concordance with a mean HRmax of 78%. Quality of CPR was similar in all groups, except for chest compression rate that was slightly higher and had less variability in the FB group. Overall chest compression depth was 41+/-4.5mm. Analysis of temporal development of chest compression depth revealed a small initial decline before leveling off. As expected, CCC group had less pauses and higher total number of chests compressions. CONCLUSION Lay people in the age group 50-76 were able to perform CPR with acceptable quality for 10min and we found only very slight temporal quality deterioration. This makes training programs for the elderly meaningful to improve survival after cardiac arrest.

Effect of Dispatcher-Assisted Cardiopulmonary Resuscitation Program and Location of Out-of-Hospital Cardiac Arrest on Survival and Neurologic Outcome

Study objective: We study the effect of a nationwide dispatcher‐assisted cardiopulmonary resuscitation (CPR) program on out‐of‐hospital cardiac arrest outcomes by arrest location (public and private settings). Methods: All emergency medical services (EMS)–treated adults in Korea with out‐of‐hospital cardiac arrests of cardiac cause were enrolled between 2012 and 2013, excluding cases witnessed by EMS providers and those with unknown outcomes. Exposure was bystander CPR categorized into 3 groups: bystander CPR with dispatcher assistance, bystander CPR without dispatcher assistance, and no bystander CPR. The endpoint was good neurologic recovery at discharge. Multivariable logistic regression analysis was performed. The final model with an interaction term was evaluated to compare the effects across settings. Results: A total of 37,924 patients (31.1% bystander CPR with dispatcher assistance, 14.3% bystander CPR without dispatcher assistance, and 54.6% no bystander CPR) were included in the final analysis. The total bystander CPR rate increased from 30.9% in quarter 1 (2012) to 55.7% in quarter 4 (2014). Bystander CPR with and without dispatcher assistance was more likely to result in higher survival with good neurologic recovery (4.8% and 5.2%, respectively) compared with no bystander CPR (2.1%). The adjusted odds ratios for good neurologic recovery were 1.50 (95% confidence interval [CI] 1.30 to 1.74) in bystander CPR with dispatcher assistance and 1.34 (95% CI 1.12 to 1.60) in bystander CPR without it compared with no bystander CPR. For arrests in private settings, the adjusted odds ratios were 1.58 (95% CI 1.30 to 1.92) in bystander CPR with dispatcher assistance and 1.28 (95% CI 0.98 to 1.67) in bystander CPR without it; in public settings, the adjusted odds ratios were 1.41 (95% CI 1.14 to 1.75) and 1.37 (95% CI 1.08 to 1.72), respectively. Conclusion: Bystander CPR regardless of dispatcher assistance was associated with improved neurologic recovery after out‐of‐hospital cardiac arrest. However, for out‐of‐hospital cardiac arrest cases in private settings, bystander CPR was associated with improved neurologic recovery only when dispatcher assistance was provided.

Quality of CPR performed by trained bystanders with optimized pre-arrival instructions

OBJECTIVE Telephone-CPR (T-CPR) can increase initiation of bystander CPR. We wanted to study if quality oriented continuous T-CPR would improve CPR performance vs. standard T-CPR. METHOD Ninety-five trained rescuers aged 22-69 were randomized to standard T-CPR or experimental continuous T-CPR (comprises continuous instructions, questions and encouragement). They were instructed to perform 10 min of chest compressions-only on a manikin, which recorded CPR performance in a small, confined kitchen. Three video-cameras captured algorithm time data, CPR technique and communication. Demography and training experience were captured during debriefing. RESULTS Participants receiving continuous T-CPR delivered significantly more chest compressions (median 1000 vs. 870 compressions, p=0.014) and compressed more frequently to a compression rate between 90 and 120 min(-1) (median 87% vs. 60% of compressions, p<0.001), compared to those receiving standard T-CPR. This also resulted in less time without compressions after CPR had started (median 12s vs. 64 s, p<0.001), but longer time interval from initiating contact with dispatcher to first chest compression (median 144 s vs. 84 s, p<0.001). There was no difference in chest compression depth (mean 47 mm vs. 48 mm, p = 0.90) or in demography, education and previous CPR training between the groups. CONCLUSION In our simulated scenario with CPR trained lay rescuers, experimental continuous T-CPR gave better chest compression rate and less hands-off time during CPR, but resulted in delayed time to first chest compression compared to standard T-CPR instructions.

A randomized trial on elderly laypersons' CPR performance in a realistic cardiac arrest simulation

Bystander cardiopulmonary resuscitation (CPR) is important for survival after cardiac arrest. We hypothesized that elderly laypersons would perform CPR poorer in a realistic cardiac arrest simulation, compared to a traditional test.

Barriers to telephone cardiopulmonary resuscitation in public and residential locations.

AIM Emergency medical telecommunicators can play a key role in improving outcomes from out-of-hospital cardiac arrest (OHCA) by providing instructions for cardiopulmonary resuscitation (CPR) to callers. Telecommunicators, however, frequently encounter barriers that obstruct the Telephone CPR (TCPR) process. The nature and frequency of these barriers in public and residential locations have not been well investigated. The aim of this study is to identify the barriers to TCPR in public and residential locations. METHODS We conducted a retrospective study of audio recordings of EMS-confirmed OHCAs from eight regional 9-1-1 dispatch centers between January 2012 and December 2013. RESULTS We reviewed 1850 eligible cases (public location OHCAs: N=223 and residential location OHCAs: N=1627). Telecommunicators less frequently encountered barriers such as inability to calm callers in public than in residential locations (2.1% vs 8.5%, p=0.002) or inability to place victims on a hard flat surface (13.9% vs 25.4%, p<0.001). However, the barrier where callers were not with patients was more frequently observed in public than in residential locations (11.8% vs 2.7%, p<0.001). CONCLUSIONS This study revealed that barriers to TCPR are distributed differently across public and residential locations. Understanding these differences can aid in the development of strategies to enhance bystander CPR and improve overall patient outcomes.

Time delays and capability of elderly to activate speaker function for continuous telephone CPR

BackgroundTelephone-CPR (T-CPR) can increase rate of bystander CPR as well as CPR quality. Instructions for T-CPR were developed when most callers used a land line. Telephones today are often wireless and can be brought to the patient. They often have speaker function which further allows the rescuer to receive instructions while performing CPR.We wanted to measure adult lay people’s ability to activate the speaker function on their own mobile phone.MethodsElderly lay people, previously trained in CPR, were contacted by telephone. Participants with speaker function experience were asked to activate this without further instructions, while participants with no experience were given instructions on how to activate it. Participants were divided in three groups; Group 1: Can activate the speaker function without instruction, Group 2: Can activate the speaker function with instruction, and Group 3: Unable to activate the speaker function. Time to activation for group 1 and 2 was compared using Mann-Whitney U-test.ResultsSeventy-two elderly lay people, mean age 68 ± 6 years participated in the study. Thirty-five (35)% of the participants were able to activate the speaker function without instructions, 29% with instructions and 36% were unable to activate the speaker function. The median time to activate the speaker function was 8s and 93s, with and without instructions, respectively (p < 0.01).ConclusionOne-third of the elderly could activate speaker function quickly, and two-third either used a long time or could not activate the function.

Targeted simulation and education to improve cardiac arrest recognition and telephone assisted CPR in an emergency medical communication centre

AIM Recognition of cardiac arrest and prompt activation time by emergency medical dispatch are key process measures that have been associated with improved survival after out-of-hospital cardiac arrest (OHCA). The aim of this study is to improve recognition of OHCA and time to initiation of telephone assisted chest compressions in an emergency medical communication centre (EMCC). METHODS A prospective, interventional study implementing targeted interventions in an EMCC. Interventions included: (1) lectures focusing on agonal breathing and interrogation strategy (2) simulation training (3) structured dispatcher feedback (4) web-based telephone assisted CPR training program. All ambulance-confirmed OHCA calls in the study period were assessed and relevant process and result measures were recorded pre- and post-intervention. Cardiac arrest was reported as (1) recognised, (2) not recognised or (3) delayed recognition. RESULTS We included 331 and 230 calls pre- and post-intervention, respectively. Recognition of cardiac arrest improved significantly after intervention (89 vs. 95%, p=0.024). Delayed recognition was significantly reduced (21 vs. 6%, p>0.001), as was misinterpretation of agonal breathing (25 vs. 10%, p<0.001). Telephone assisted compressions increased (71% vs. 83%, p=0.002) whereas bystander performed ventilations decreased after intervention (23% vs. 15%, p=0.016). Time intervals for initiation of chest compression instructions (2.6 vs. 2.3min, p=0.042) and delivery of telephone assisted chest compressions (3.3 vs. 2.8min, p=0.015) were significantly shortened after intervention. CONCLUSION Targeted simulation, education and feedback significantly improved recognition of OHCA and reduced time to first chest compression. Continuous measurement of key quality metrics can facilitate development of targeted education and training.

Chest compression rate measurement from smartphone video

BackgroundOut-of-hospital cardiac arrest is a life threatening situation where the first person performing cardiopulmonary resuscitation (CPR) most often is a bystander without medical training. Some existing smartphone apps can call the emergency number and provide for example global positioning system (GPS) location like Hjelp 113-GPS App by the Norwegian air ambulance. We propose to extend functionality of such apps by using the built in camera in a smartphone to capture video of the CPR performed, primarily to estimate the duration and rate of the chest compression executed, if any.MethodsAll calculations are done in real time, and both the caller and the dispatcher will receive the compression rate feedback when detected. The proposed algorithm is based on finding a dynamic region of interest in the video frames, and thereafter evaluating the power spectral density by computing the fast fourier transform over sliding windows. The power of the dominating frequencies is compared to the power of the frequency area of interest. The system is tested on different persons, male and female, in different scenarios addressing target compression rates, background disturbances, compression with mouth-to-mouth ventilation, various background illuminations and phone placements. All tests were done on a recording Laerdal manikin, providing true compression rates for comparison.ResultsOverall, the algorithm is seen to be promising, and it manages a number of disturbances and light situations. For target rates at 110 cpm, as recommended during CPR, the mean error in compression rate (Standard dev. over tests in parentheses) is 3.6 (0.8) for short hair bystanders, and 8.7 (6.0) including medium and long haired bystanders.ConclusionsThe presented method shows that it is feasible to detect the compression rate of chest compressions performed by a bystander by placing the smartphone close to the patient, and using the built-in camera combined with a video processing algorithm performed real-time on the device.

Real-Time Chest Compression Quality Measurements by Smartphone Camera

Out-of-hospital cardiac arrest (OHCA) is recognized as a global mortality challenge, and digital strategies could contribute to increase the chance of survival. In this paper, we investigate if cardiopulmonary resuscitation (CPR) quality measurement using smartphone video analysis in real-time is feasible for a range of conditions. With the use of a web-connected smartphone application which utilizes the smartphone camera, we detect inactivity and chest compressions and measure chest compression rate with real-time feedback to both the caller who performs chest compressions and over the web to the dispatcher who coaches the caller on chest compressions. The application estimates compression rate with 0.5 s update interval, time to first stable compression rate (TFSCR), active compression time (TC), hands-off time (TWC), average compression rate (ACR), and total number of compressions (NC). Four experiments were performed to test the accuracy of the calculated chest compression rate under different conditions, and a fifth experiment was done to test the accuracy of the CPR summary parameters TFSCR, TC, TWC, ACR, and NC. Average compression rate detection error was 2.7 compressions per minute (±5.0 cpm), the calculated chest compression rate was within ±10 cpm in 98% (±5.5) of the time, and the average error of the summary CPR parameters was 4.5% (±3.6). The results show that real-time chest compression quality measurement by smartphone camera in simulated cardiac arrest is feasible under the conditions tested.