Chest Compression Cardiopulmonary Resuscitation Research Articles

Chest compression quality comparing 1-min vs 2-min rotation of rescuers wearing N95 masks

BackgroundDuring the COVID-19 pandemic, cardiopulmonary resuscitation (CPR) performed by rescuers wearing well-sealed respirators such as N95 masks, was associated with significant reduction in the chest compression rate and depth. This was attributed to fatigue during the standard 2-min rescuer rotations. We hypothesized that in such situations, rotating rescuers every one minute, instead of the standard two minutes would improve CPR quality. AimTo compare the quality of chest compressions when rescuers wearing N95 masks are rotated every one minute, instead of the standard practice of two-minute rotations. MethodsA randomized, controlled, crossover trial was conducted, with the approval of the institutional Ethics Committee. Medical students who volunteered as rescuers were trained to perform high-quality chest compressions on a manikin, and then randomly allocated into pairs. Each pair was randomized to one of two trial groups viz. one-minute rotations crossed-over to two-minute rotations; and vice versa. Thus, each pair performed CPR with one-minute rotations, as well as two-minute rotations Each CPR session included chest compressions for a duration of 12 min. The outcome parameters included CPR quality, compression depth, compression rate, and chest compression fraction. Rescuer fatigue was measured before and after each study session using the modified Borg scale. ResultsFifty-six participants completed the study. The overall CPR quality was statistically similar in the study arms (median 88% vs. 81%, p = 0.09). However, the minute-to-minute inter-arm comparison revealed significantly lower CPR quality in the 2-min rotation arm, at the end of minutes 4, 6, 8, 10 and 12 (respective p-values 0.03, 0.001, 0.008, 0.02, 0.002). A similar trend was observed in compression depth also. Rescuer fatigue score was significantly less with 1-min rotations compared to 2-min rotations (p < 0.001). Rescuer vital signs and cardiorespiratory parameters were not different with the two types of rotations. ConclusionDuring CPR performed by rescuers wearing N95 masks, the quality of CPR appears to be superior with rescuers rotating at 1-min instead of 2-min intervals. More frequent rotation was also associated with less rescuer fatigue.

Mouse Cardiac Arrest Model for Brain Imaging and Brain Physiology Monitoring During Ischemia and Resuscitation.

Most cardiac arrest (CA) survivors experience varying degrees of neurologic deficits. To understand the mechanisms that underpin CA-induced brain injury and, subsequently, develop effective treatments, experimental CA research is essential. To this end, a few mouse CA models have been established. In most of these models, the mice are placed in the supine position in order to perform chest compression for cardiopulmonary resuscitation (CPR). However, this resuscitation procedure makes the real-time imaging/monitoring of brain physiology during CA and resuscitation challenging. To obtain such critical knowledge, the present protocol presents a mouse asphyxia CA model that does not require the chest compression CPR step. This model allows for the study of dynamic changes in blood flow, vascular structure, electrical potentials, and brain tissue oxygen from the pre-CA baseline to early post-CA reperfusion. Importantly, this model applies to aged mice. Thus, this mouse CA model is expected to be a critical tool for deciphering the impact of CA on brain physiology.

Using real-time device-based visual feedback in CPR recertification programs: A prospective randomised controlled study

BackgroundReceiving regular training to maintain CPR skills is critical for in-service health-care professionals, especially because motor skills diminish over time. ObjectivesTo compare the effects of real-time device-based visual feedback and conventional instructor-based feedback on the chest compression skills and self-efficacy of nurses receiving a CPR recertification program. DesignA prospective randomised controlled study with repeated measurements was conducted according to the CONSORT 2010 guidelines. MethodsA total of 109 nurses were recruited, and 98 nurses were eligible for random allocation. The control group (CG, n = 49) was advised by instructors for skill correction, and the experimental group (EG, n = 49) adjusted their skills according to on-screen real-time feedback data. The study outcomes were CPR performance metrics and self-efficacy that were assessed immediately after the training session (T1) and retested after 12 weeks (T2). ResultsIn the EG, the percentage of the appropriate rate, depth, and chest recoil at T1 significantly improved by 24.47 % (P < .001), 19.63 % (P < .001), and 11.52 % (P = .001), respectively. The EG exhibited significantly higher chest compression total scores at T1, and the difference remained significant at T2 (P < 0.001). Moreover, the self-efficacy in the EG significantly improved at T1 (2.76; P < .001) and T2 (2.58; P < .001). ConclusionCompared with instructor-based feedback, real-time device-based visual feedback improved chest compression quality and CPR self-efficacy.

Cardiopulmonary resuscitation: difficulty in maintaining sufficient compression depth at the appropriate rate

Over the last 50 years, the recommended chest compression for cardiopulmonary resuscitation (CPR) has become faster and deeper, but maintaining deep compressions may be difficult at higher rates. Our study aimed to determine whether adequate compression (chest compression at an appropriate depth and rate) is being performed in emergency departments (ED). We also investigated the effect of adequate compression performance on the return of spontaneous circulation (ROSC). This prospective observational study was conducted at the EDs of two urban academic medical centers. We included adult patients (age ≥18 years) with cardiac arrest who underwent CPR in the ED between May and November 2020. We excluded patients with cardiac arrest related to trauma, repeated arrest except the first, and those for whom a monitor-defibrillator (ZOLL X-series) was not used. The following data were obtained from the monitor-defibrillator devices: compression depth, rate, chest compression fraction, CPR time, and percentage of compressions at the recommended rate and, at the recommended depth, at over and below rates, and depth, and at the appropriate depth and rate. Our study included 50 patients, from whom 441 chest compression sequences were obtained and analyzed. The mean compression depth, rate, and fraction were 6.48 ± 0.87 cm, 117 ± 5/min, 92.1 ± 3.70%, respectively. As the compression rate increased, the depth decreased, and most compressions were over-depth. Adequate compression (appropriate depth at recommended rate) was observed in 97 of the 441 compression sequences (21.9%). Below-depth and below-rate percentages were higher in the deceased group than that in the ROSC group (9.7 ± 15.2% vs. 3.3 ± 3.5%, p = 0.27; 2.7 ± 2.6% vs. 1.2± 0.9%, p = 0.06). The global ratio of chest compression showed low compliance with the recommended rate and depth, even when performed by skilled ED staff.

GAMBARAN PELAKSANAAN CPR DENGAN LAGU SORRY - JUSTIN BIEBER TERHADAP KECEPATAN KOMPRESI DADA PADA PENOLONG AWAM

Cardiopulmonary resuscitation (CPR) with a chest compression rate of 100 - 120 beats per minute is difficult without guidance. To maintain chest compression, the rhythm of a song can stabilize CPR rates of 100 - 120 beats per minute. The purpose of this study was to describe the implementation of CPR with the song Sorry-Justin Bieber on the speed of chest compression for lay rescuers. The method uses quantitative research with descriptive design with 30 respondents and uses probability sampling technique with random sampling. The instrument used is a QCPR Training application. Data were analyzed using descriptive statistic. The result of this research are compression speed have an average result of 109,83 beats / minute with a minimum speed of 100, maximum speed of 116, and standard deviation of 5,446. The success rate of respondents in performing chest compression is known to be 30 successful respondents. Hands Only CPR chest compression speed using the song Sorry - Justin Bieber had good results. Variations in the results of chest compression in this study were still within the range of 100 - 120 beats / minute in accordance with high quality CPR standards. This shows the picture that when performing Hands Only CPR with the song Sorry - Justin Bieber, the chest compression speed level will meet the right compression speed standard.

Evaluation of abdominal compression–decompression combined with chest compression CPR performed by a new device: Is the prognosis improved after this combination CPR technique?

IntroductionThis study was designed to compare the outcomes of standard cardiopulmonary resuscitation (STD-CPR) and combined chest compression and abdominal compression–decompression cardiopulmonary resuscitation (CO-CPR) with a new device following out-of-hospital cardiac arrest (OHCA). Moreover, we investigated whether patient prognosis improved with this combination treatment.MethodsThis trial was a single-centre, prospective, randomized trial, and a blinded assessment of the outcomes was performed. A total of 297 consecutive patients with OHCA were initially screened, and 278 were randomized to the STD-CPR group (n = 135) or the CO-CPR group (n = 143). We compared the proportions of patients who achieved a return of spontaneous circulation (ROSC), survived to hospital admission and survived to hospital discharge. In addition, we also performed the Kaplan–Meier analysis with a log-rank test at the end of the follow-up period to compare the survival curves of the two groups.ResultsThe differences were not statistically significant in the proportion of patients who achieved ROSC [31/135 (23.0%) versus 35/143 (24.5%)] and survived to hospital admission [28/135 (20.7%) versus 33/143 (23.1%)] between the CO-CPR group and STD-CPR group. However, there was a significant difference in the proportion of patients who survived to hospital discharge [16/135 (11.9%) versus 7/143 (4.9%)] between the two groups. Nine patients (6.7%) in the CO-CPR group and 2 patients (1.4%) in the STD group showed good neurological outcomes according to the cerebral performance category (CPC) scale score, and the difference was statistically significant (P = 0.003). The Kaplan–Meier curves showed that the patients in the CO-CPR group achieved better survival benefits than those in the STD-CPR group at the end of the follow-up period (log-rank P = 0.007).ConclusionCO-CPR was more beneficial than STD-CPR in terms of survival benefits in patients who have suffered out-of-hospital cardiac arrest.Trial registration Chinese Clinical Trial Registry, registered number: ChiCTR2100049581. Registered 30 July 2021- Retrospectively registered. http://www.medresman.org.cn/uc/index.aspx.

Analysis of the adequacy of infant cardiopulmonary resuscitation according to chest compression technique based on the 2020 AHA guidelines

The quantitative and qualitative differences between the two-finger (TF) and two-thumb-encircling hands (TT) techniques were not sufficiently investigated to determine which is more effective for single-rescuer infant cardiopulmonary resuscitation (CPR). As the type of chest compression (CC) technique can impact survival rates and prognoses of patients, this study aimed to compare the adequacy of single-rescuer infant CPR CC techniques and explore participants’ CPR experiences using an exploratory sequential mixed methods design. To assess the adequacy of CC and ventilation according to technique, 70 students who completed basic life support provider certification among students from emergency medical services and nursing departments of a single college performed CC using the TF and TT techniques (4 sets of 5 cycles with a ratio of 30:2) in simulation. Meanwhile, a numeric rating scale was used to measure fatigue. SPSS (v. 25.0, IBM Corp, Armonk, NY, USA) was used to analyze the collected data by frequency analysis, descriptive statistics, paired t-test, and repeated measures analysis of variance (ANOVA). We conducted focus group interviews and analyzed CPR experiences. There were statistically significant differences between the TF and TT techniques in fatigue score (6.09 vs. 4.23 points, p &lt; 0.001), average hands-off time (6.77 vs. 7.43 s, p =0.001), mean ventilation volume (41.40 vs. 35.51 ml, p = 0.002), CC accuracy rate (65.89% vs. 77.11%, p = 0.011), mean CC rate (104.37 vs. 107.11 beats/min, p = 0.020), overall CPR score (78.26 vs. 84.37 points, p = 0.005), and overall compression score (82.60 vs. 92.54 points, p &lt; 0.001). Furthermore, we found significant differences over time in mean CC count (p = 0.030), mean ventilation volume (p = 0.042), and mean hands-off time (p = 0.029). Two categories (ambivalent attitudes and perception of pain) and five sub-categories were derived based on the results. In conclusion, as stated in the 2020 American Heart Association (AHA) guidelines, both TF and TT techniques are useful for single-rescuer infant CPR. Overall, TT technique provides higher quality of compressions at the cost of fewer ventilations. We recommend future studies of more diverse groups and techniques.

Effect of synchronous online vs. face-to-face cardiopulmonary resuscitation training on chest compression quality: A pilot randomized manikin study

The aim of the study was to compare the effect of synchronous online and face-to-face cardiopulmonary resuscitation (CPR) training on chest compressions quality in a manikin model. A total of 118 fourth-year medical students participated in this study. The participants were divided into two groups: the online synchronous teaching group and the face-to-face group. Then, the participants were further randomly distributed to 1 of 2 feedback groups: online synchronous teaching and training with feedback devices (TF, n = 30) or without feedback devices (TN, n = 29) and face-to-face teaching and training with feedback devices (FF, n = 30) or without feedback devices (FN, n = 29). In the FN group and FF group, instructors delivered a 45-min CPR training program and gave feedback and guidance during training on site. In the TN group and TF group, the participants were trained with an online lecture via Tencent Meeting live broadcasting. Finally, participants performed a 2-min continuous chest compression (CC) during a simulated cardiopulmonary arrest scene without the audiovisual feedback (AVF) device. The outcome measures included CC depth, CC rate, proportions of appropriate depth (50-60 mm) and CC rate (100-120/min), percentage of correct hand location position, and percentage of complete chest recoil. There was little difference in the CC quality between the synchronous online training groups and the face-to-face training groups. There was no statistically significant difference in CC quality between the TN group and FN group. There were also no statistically significant differences between the TF and FF groups in terms of correct hand position, CC depth, appropriate CC depth, complete chest recoil or CC rate. However, the FF group had a higher appropriate CC rate than the TF group (p = 0.045). In the face-to-face training groups, the AVF device group had a significantly greater CC depth, appropriate CC depth, CC rate, and appropriate CC rate. However, there was a lack of statistically significant differences in terms of correct hand position (p = 0.191) and appropriate CC depth (p = 0.123). In the synchronous online training groups, the AVF device had little effect on the CC rate (p = 0.851) and increased the appropriate CC rate, but the difference was not statistically significant (p = 0.178). Synchronous online training with an AVF device would be a potential alternative approach to face-to-face chest compression training. Synchronous online training with AVF devices seems to be a suitable replacement for face-to-face training to offer adequate bystander CPR chest compression training.

Abstract 11939: Can Live Video Streaming From Bystander's Smartphone Improve the Quality of Chest Compressions in Real Out-of-Hospital Cardiac Arrest?

Introduction: Good quality of cardiopulmonary resuscitation (CPR) provided by bystanders is important for the outcome in out-of-hospital cardiac arrest (OHCA). A live video stream from the bystander’s smartphone to the medical dispatcher might improve the quality of chest compressions performed during CPR. Methods: At the Copenhagen Emergency Medical Services in Denmark, the medical dispatcher can add a live video to the emergency call. In case of OHCA, the medical dispatcher guides bystanders in dispatcher-assisted CPR (DA-CPR). After initiating chest compressions, the medical dispatcher can add live video streaming. A cohort study was conducted with an evaluation of performed chest compressions from the video footage before and after the dispatcher used the video to instruct CPR (video-instructed DA-CPR). Correct chest compressions were defined according to European Resuscitation Council Guidelines. Results: CPR was provided with a live video stream in 52 OHCA calls, in which 90 bystanders performed chest compressions. Thirty OHCA occurred at a public location, and more than four bystanders were present in 32 (62%) cases. In 26 cases, chest compressions were performed by more than one bystander. Eight (9%) bystanders performed correct chest compressions before video-instructed DA-CPR. For the bystanders first initiating insufficient CPR improvements were observed for: hand placement 58% (n=17/29), compressions rate 73% (n=17/21), and compressions depth 62% (n=19/31) following video-instructed DA-CPR. For the second bystander providing CPR (n=26) improvements were still observed for: hand placement 57% (n=4/7), compressions rate 73% (N=8/11), and compressions depth 53% (n=11/21) following video-instructed DA-CPR. For the third and fourth bystander (n=10), providing CPR improvements were seen for: hand placement 100% (n=2/2), compressions rate 50 % (n=2/4), and compressions depth 60% (n=3/5). Eighteen bystanders had a chest compressions performance measurement that could not be observed. Conclusions: A live video from the bystander`s smartphone to the medical dispatcher could improve the quality of chest compressions in CPR, and guidance seems important not just for the first bystander but for all bystanders performing CPR.

Identification of an optimal CPR chest compression protocol.

In this study, we used a high-fidelity integrated computational model of the respiratory and cardiovascular systems to investigate cardiopulmonary resuscitation (CPR) after cardiac arrest in a virtual healthy subject. For the purpose of this work, a newly developed thoracic model has been integrated to the current model, to study the influence of external chest compressions upon the arrested circulation during CPR. We evaluated the chest compression (CC) parameters, namely, end compression force, compression rate, and duty cycle to optimize the coronary perfusion pressure and the systolic blood pressure, using a genetic algorithm. While the sternal displacement associated with the CC force agreed with the ERC guidelines, the CC rate and duty cycle were respectively higher and lower than the ones recommended by the ERC guidelines. The effect of these CC parameters on cardiac output (CO) were also assessed. The end compression force was the parameter with the largest impact on CO, while the compression rate and duty cycle scarcely influence it.Relevance- Our results may aid in understanding the underlying pathophysiology of cardiac arrest and help guide research into the refinement of CPR strategies, without sacrificing animals or conducting clinical trials, which are difficult to undertake in crisis scenarios.

Is continuous chest compression CPR by untrained bystanders more effective than conventional CPR with rescue breathing? A Cochrane Corner for the IJFAE

Is continuous chest compression CPR by untrained bystanders more effective than conventional CPR with rescue breathing? A Cochrane Corner for the IJFAE

Comparison of femoral and carotid arteries in terms of pulse check in cardiopulmonary resuscitation: A prospective observational study

Detecting the presence of a pulse is pivotal to initiating and guiding cardiopulmonary resuscitation (CPR). Palpating the carotid or femoral artery pulse are historically the most common areas providers assess during a resuscitation. Unfortunately manual palpation of a pulse is operator dependent and varies based on patient anatomical differences and vital signs. The Advanced Cardiac Life Support (ACLS) guidelines defined by the American Heart Association (AHA) states that pulse checks should be accomplished quickly to minimize time between chest compressions in CPR.

Comparison of femoral and carotid arteries in terms of pulse check in cardiopulmonary resuscitation: A prospective observational study

Detecting the presence of a pulse is pivotal to initiating and guiding cardiopulmonary resuscitation (CPR). Palpating the carotid or femoral artery pulse are historically the most common areas providers assess during a resuscitation. Unfortunately manual palpation of a pulse is operator dependent and varies based on patient anatomical differences and vital signs. The Advanced Cardiac Life Support (ACLS) guidelines defined by the American Heart Association (AHA) states that pulse checks should be accomplished quickly to minimize time between chest compressions in CPR. Manual pulse checks are the most common, but there is no consensus on the most accurate and efficient location to perform a manual pulse check.

A novel mechanical chest compressor with rapid deployment in all population cardiopulmonary resuscitation

Cardiopulmonary resuscitation (CPR) resuscitates patients suffering from cardiac arrest. Mechanical chest compression CPR highlights the need for high CPR quality to facilitate survival and neurological recovery. However, current CPR devices cannot be used on pregnant women or infants. These devices’ long re-setup times interrupt CPR and can cause cerebral ischemia. This study designed a novel device with a crank-sliding mechanism. The polar coordinate system (r, θ, z) shortened the setup time and enabled adjustment without moving the patient. We compared our device with commercial products (e.g., LUCAS-2) by quantifying the compression pressure. Control groups for manual CPR of trained physicians and untrained citizens were recruited. We used Resusci Anne products as models. Our results indicated that our design exhibited performance similar to that of LUCAS-2 in adults (557.8 vs. 623.6 mmHg, p = 0.217) and met the current CPR standard guidelines. Notably, our device is applicable to pregnant women [565 vs. 564.5 (adults) mmHg, p = 0.987] and infants [570.8 vs. 564.5 (adults) mmHg, p = 0.801] without lowering the compression quality. The overall compression quality and stability of mechanical chest compression CPR were favorable to those of manual CPR. Our device provides an innovative prototype for the next generation of CPR facilities.

Factors Influencing Rate of Chest Compression in Cardio Pulmonary Resuscitation (CPR) by Nurses as a First Responder

Introduction: Cardiac arrest is a condition of the cessation of blood circulation in the body. First aid cardiac arrest is cardiopulmonary resuscitation consisting of chest compression and ventilation. Chest compression is a factor that affects the return of spontaneous circulation (ROSC) patients. In addition to the depth of chest compressions, the chest compression rate is a major factor that can increase the chances of the patient’s life shortly after suffering a cardiac arrest. Aim: The purpose of this study is to determine the factors that affect the rate of the chest compressions performed by nurses as a first responder. Method: The method used in this study is analytic cross sectional correlative to 107 respondents. Chest compression rate measurement using a chest compression CPR Help Zoll’s Real product was analyzed using an application Rescue Net Code Review. Finding: Preliminary study results showed that the factors that affect the rate of the chest compression is gender, age, BMI, education, the last time attend to BLS training and the last time giving chest compressions. Based on the results of the linear regression analysis, gender is a factor that most affects to the rate of the chest compression (β = -7.8). It explains that the male responder provide a faster compression 8x/min compared with female responder. Conclusion: In conclusion, gender, the last time attends to BLS training and the last time provides chest compression significantly affect to the rate of the chest compression

The effects of a passive exoskeleton on trunk muscle activity and perceived exertion for experienced auxiliary medical service providers in cardiopulmonary resuscitation chest compression

The effects of a passive exoskeleton on trunk muscle activity and perceived exertion for experienced auxiliary medical service providers in cardiopulmonary resuscitation chest compression

Comparing the efficiency and convenience of one-rescuer cardiopulmonary resuscitation chest compression techniques for infants

Comparing the efficiency and convenience of one-rescuer cardiopulmonary resuscitation chest compression techniques for infants

Feasible study of carotid artery Doppler ultrasound blood flow measurement during chest compression cardiopulmonary resuscitation

To determine the feasibility of ultrasound to measure blood flow on patients with chest compression cardiopulmonary resuscitation (CPR), and to find out a real-time, noninvasive hemodynamic evaluation method. A prospective study was conducted. All adult patients undergoing CPR admitted to Department of Emergency and intensive care unit (ICU) of Zhengzhou People's Hospital from May 2016 to November 2018 were enrolled. The blood flow over the right carotid arteries during chest compressions was recorded with a bedside ultrasound machine. The peak systolic flow velocity (PSV) and end diastolic flow velocity (EDV) of carotid artery were recorded at 1 minute after the start of CPR and 1 minute before the end of CPR. The mean compression frequency during the whole recovery period was recorded, the rate of compression reaching the standard was evaluated by ultrasound (the rate of compression 100-120 times/min was defined as up to standard), and the interruption time of compression was calculated retrospectively according to the ultrasound image data recorded during CPR. Thirty-nine patients were enrolled, and 21 patients were successfully rescued, with a successful rate of 53.8%, the time of restoration of spontaneous circulation (ROSC) was (10.9±5.3) minutes. The time from CPR to retrieve an ultrasound image was 1.1-4.9 minutes, with an average of (2.5±1.2) minutes. Satisfactory ultra-sonographic images were obtained in 28 patients during the whole course of chest compression. The acquisition rate was 71.8% (28/39). In the process of compression, if the frequency of compression was less than 100 times/min or the velocity of carotid artery dropped (PSV < 30 cm/s), the chest compressors should be reminded and corrected in time. The PSV at 1 minute after CPR start of 28 patients with satisfactory ultrasound images was (62.9±18.5) cm/s, and the EDV was (13.9±3.5) cm/s, the PSV at 1 minute before the end of CPR was (55.4±18.4) cm/s, and the EDV was (12.9±3.7) cm/s. There was no significant difference in above parameters between the two time points (both P > 0.05), suggesting that satisfactory resuscitation effect was achieved in the whole process of CPR. The compression frequency of 28 patients was 100-149 times/min with an average of (117±47) times/min. The rate of compression with standard was 85.7% (24/28), and the total interruption time of compression accounted for 4.4% of all compression time (25.9 minutes/587.2 minutes). Ultrasound measurement of common carotid artery blood flow during CPR has the advantage of real-time and non-invasive, and it is feasible in clinical work.

Effects of ‘Rescuer’ Rotating Time on the Quality of Chest Compressions: 1-Minute Vs. 2-Minute Intervals

Introduction Fatigue can influence the quality of continuous chest compression cardiopulmonary resuscitation (CCC-CPR). This study was conducted to compare the effect of ‘rescuer’ rotating time on the quality of chest compressions at 1-minute and 2-minute intervals. Methods The present semi-experimental study was conducted on 70 non-professional ‘rescuers’ as 35 two-person teams using a crossover design. All teams performed eight 2-minute cycles of CCC-CPR with a rotation of 1 minute and 2 minutes. Quality metrics of the chest compression rate, appropriate depth of compression, and total rate of compressions at the end of eight 2-minute cycles were used to assess the quality of the chest compressions. Results The study results showed that the number of chest compressions with an adequate depth performed by the non-professional rescuers in the 1- and 2-minute scenarios wererespectively 118.18 and 100.87. There was no significant difference in the number of chest compressions between the two scenarios at the end of the CCC-CPR, but the number of compressions with sufficient depth in the 1-minute scenario was better than that in the 2-minute scenario. Conclusion The study showed that although the rate of chest compression had a downward trend in the 1-minute scenario, rescuers maintained 100 to 120 chest compressions after 16 minutes. This means that non-professional rescuers replacement after 1 minute can increase chest compression with sufficient depth.

Abstract 141: Resuscitation Time Bias in an Observational Study of Mechanical Chest Compression CPR

Recent observational studies have found associations between poorer outcomes and treatment that included mechanical CPR devices, contradicting findings from randomized trials. Resuscitation time bias is a systematic error occurring in observational studies of interventions applied to pulseless patients later in resuscitation attempts. Previous observational studies lack data on duration of resuscitation, a factor strongly related to outcome. We retrospectively analyzed cardiac arrest data to learn how resuscitation time and device use relate to clinical outcomes, and determine whether resuscitation time bias was present. Methods and Results: We analyzed data from all 49 patients with ventricular fibrillation, out-of-hospital cardiac arrest treated by our emergency medical service in one year. We compared 19 patients who received only standard manual CPR (the sCPR group) to 30 patients who received manual followed by mechanical CPR (the mCPR group). Response to CPR differed between groups even before device application. All sCPR patients achieved return of spontaneous circulation (ROSC), and did so after a median (IQR) of 3.3 (2.2-5.1) minutes of manual CPR. Patients in the mCPR group failed to get ROSC through 6.9 (5.3-11.0) min of manual CPR; mCPR patients that did get ROSC did so after 11.2 (5.7-23.8) additional minutes of CPR, delivered by a mechanical device. mCPR patients also received significantly more defibrillations and ALS drugs. ROSC and survival to hospital discharge were higher in the sCPR than the mCPR group (100% vs. 70%, P = 0.008; 74% vs. 43%, P = 0.045). Conclusion: Only patients remaining pulseless after early resuscitation efforts received mechanical CPR. Consequently, mechanical CPR devices assisted by facilitating prolonged treatment of patients who already had lower chances of survival before device application. Resuscitation time bias was present, and must be considered when interpreting registry reports comparing sCPR and mCPR.