Compression Fraction Research Articles

The effect of strength training on quality of prolonged basic cardiopulmonary resuscitation.

Providing high-quality chest compressions and rescue breaths are key elements in the effectiveness of cardio-pulmonary resuscitation. To investigate the effects of a strength training programme on the quality of prolonged basic cardiopulmonary resuscitation on a manikin. This was a quasi-experimental trial. Thirty-nine participants with prior basic life support knowledge were randomised to an experimental or control group. They then performed a test of 10 min of chest compressions and mouth-to-mouth ventilation on manikins equipped with a skill reporter tool (baseline or test 1). The experimental group participated in a four-week strength training programme focused on the muscles involved in chest compressions. Both groups were subsequently tested again (test 2). After training, the experimental group significantly increased the mean depth of compression (53.7 ± 2.3 mm vs. 49.9 ± 5.9 mm; p = 0.003) and the correct compression fraction (68.2 ± 21.0% vs. 46.4 ± 29.1%; p = 0.004). Trained subjects maintained chest compression quality over time better than the control group. The mean tidal volume delivered was higher in the experimental than in the control group (701.5 ± 187.0 mL vs. 584.8 ± 113.6 mL; p = 0.040) and above the current resuscitation guidelines. In test 2, the percentage of rescue breaths with excessive volume was higher in the experi-mental group than in the controls (31.5 ± 19.6% vs. 15.6 ± 13.0%; p = 0.007). A simple strength training programme has a significant impact on the quality of chest compressions and its maintenance over time. Additional training is needed to avoid over-ventilation of potential patients.

Chest compression fraction in ambulance while transporting patients with out-of-hospital cardiac arrest to the hospital in rural Taiwan

IntroductionMaintaining the standard two-handed chest compression is difficult in high-speed ambulances in rural areas.MethodsA retrospective, video-based, observational study was conducted from June to September 2013 in Nantou, a rural county...

Abstract 12684: Cpr Quality During Out- Of- Hospital Cardiac Arrest Transport

Background: Previous studies have demonstrated significant associations between cardiopulmonary resuscitation (CPR) quality metrics and survival to hospital discharge following out-of- hospital cardiac arrest (OHCA). No large study has explored the relationship between location of resuscitation (scene vs. transport) and CPR quality. Objective: We sought to determine the impact of CPR location on CPR quality metrics during OHCA. Methods: We performed a retrospective cohort study of prospectively collected data from the Toronto RescuNET Epistry- cardiac arrest database. We analyzed CPR quality data from all treated adult OHCA occurring over a 39 month period beginning January 1, 2013. We included OHCA patients who underwent resuscitation by emergency medical services and had CPR quality metric data for both scene and transport phases of the resuscitation. Based on 2010 American Heart Association guidelines, high quality CPR was defined as chest compression fraction (CCF)> 0.70, compression rate >100/min and compression depth > 5.0 cm. Scene and transport CPR quality metrics were compared for each patient using a Wilcoxon rank-sum paired-samples test . The proportion of patients who received high quality CPR (defined as meeting all 3 CPR quality benchmarks) was compared between resuscitation locations using a chi-square statistic. Results: Amongst 842 included patients (69.5% male, mean (SD) age 66.8±17.0), median compression rate was statistically higher on scene compared to transport (105.8 vs. 102.0 ; Δ 3.8; 95% CI: 2.5, 4.0), while median compression depth (5.56 vs. 5.33; Δ 0.23; 95% CI: 0.12, 0.26) and median CCF (0.95 vs. 0.87; Δ 0.08; 95% CI: 0.07, 0.08) were statistically higher during the transport phase. The proportion of patients with high quality CPR was similar on scene compared to during transport (45.8% vs. 42.5%; Δ 3.3; 95% CI: -1.4, 8.1). Conclusions: High quality CPR metrics were identified in both (scene and transport) locations of resuscitation and exceeded current CPR quality benchmarks. These results suggest that high quality, manual compressions can be performed by well-trained EMS systems regardless of location. Further study is required to determine whether these metrics can be replicated in other EMS jurisdictions.

Abstract 13871: Does Compliance With a Global Cpr Quality Benchmark Predict Survival From Out-Of-Hospital Cardiac Arrest?

Background: Measures of chest compression fraction (CCF), compression rate, compression depth and pre-shock pause have all been independently associated with improved outcomes from out-of-hospital (OHCA) cardiac arrest. However, it is unknown whether compliance with a global CPR quality benchmark, incorporating the aforementioned metrics, can predict OHCA survival. Methods: We performed a secondary analysis of prospectively collected data from the Resuscitation Outcomes Consortium Cardiac Arrest Epistry database. As per the 2015 American Heart Association (AHA) guidelines, high quality CPR was defined as CCF > 0.8, chest compression rate 100-120/minute, chest compression depth 50-60 mm and pre-shock pause< 10 seconds. To derive a global CPR quality benchmark, we created multiple models employing combinations of CPR metrics to assess relationships between CPR compliance and survival to hospital discharge. Multivariable logistic regression models controlling for age, gender, witnessed status, bystander CPR, location, presenting rhythm and site were used to assess the relationship between compliance with a global CPR quality benchmark, survival to hospital discharge and neurologically intact survival with MRS < 2. Results: We analyzed CPR process data from 35,445 defibrillator records collected over a 4 year time frame ending in June 2015. Of the 35,445 records, 19,568 (55.2%) included compression depth. For the primary model (CCF, rate, depth), there was no improvement in survival from OHCA comparing resuscitations that met no CPR quality benchmarks (reference) to those who met all CPR quality benchmarks (OR 0.89; 95% CI: 0.47, 1.70) and those who met some of the CPR quality benchmarks (OR 0.71; 95% CI: 0.45, 1.13). Models combining CCF, rate, depth and pre-shock pause yielded similar results for both shockable and non- shockable presenting rhythms when controlling for Utstein variables. Conclusions: When modeled in combination and adjusting for other predictors of survival, a global CPR quality benchmark using the current AHA guidelines was not associated with improved survival from OHCA. Unmeasured confounders, unknown combinations of optimal CPR quality metrics or possible interactions may explain our study findings.

The impact of post-resuscitation feedback for paramedics on the quality of cardiopulmonary resuscitation

PurposeThe Guidelines place emphasis on high-quality cardiopulmonary resuscitation (CPR). This study aims to measure the impact of post-resuscitation feedback on the quality of CPR as performed by ambulance personnel. Materials and methodsTwo ambulances are dispatched for suspected cardiac arrest. The crew (driver and paramedic) of the first arriving ambulance is responsible for the quality of CPR. The crew of the second ambulance establishes an intravenous access and supports the first crew. All resuscitation attempts led by the ambulance crew of the study region were reviewed by two research paramedics and structured feedback was given based on defibrillator recording with impedance signal. A 12-months period before introduction of post-resuscitation feedback was compared with a 19-months period after introduction of feedback, excluding a six months run-in interval. Quality parameters were chest compression fraction (CCF), chest compression rate, longest peri-shock pause and longest non-shock pause. ResultsIn the pre-feedback period 55 cases were analyzed and 69 cases in the feedback period. Median CCF improved significantly in the feedback period (79% vs 86%, p<0.001). The mean chest compression rate was within the recommended range of 100–120/min in 87% of the cases in the pre-feedback period and in 90% of the cases in the feedback period (p=0.65). The duration of longest non-shock pause decreased significantly (40s vs 19s, p<0.001), the duration of the longest peri-shock pause did not change significantly (16s vs 13s, p=0.27). ConclusionPost-resuscitation feedback improves the quality of resuscitation, significantly increasing CCF and decreasing the duration of longest non-shock pauses.

A usability study of a critical man–machine interface: Can layperson responders perform optimal compression rates when using a public access defibrillator with automated real-time feedback during cardiopulmonary resuscitation?

Objective: Many public access defibrillators (PADs) incorporate computer programs to provide audiovisual feedback to assist the user to deliver cardiopulmonary resuscitation (CPR) according to current international guidelines. This usability study assessed if a PAD integrated with a real-time audiovisual CPR feedback system can guide lay-users to optimum chest compression rates, and if it is detrimental to chest compression depth. Methods: Randomly selected volunteers (15+ years) were recruited for two experiments. Experiment 1 $(n = 156)$ assessed the time taken to achieve the “good speed” audio prompt (i.e., perform compressions at a rate of 100–120 compressions/min) and chest compression fraction (CCF). Experiment 2 $(n = 140)$ assessed the effect of rate-only CPR feedback on chest compression depth. Two devices of the same model were used: one with CPR rate feedback and the other with CPR feedback disabled. The difference in compression depths and CCF was assessed. Results: Experiment 1: A total of 136 (87.2%) participants achieved “good speed” within 45 s with a mean CCF of 90.3% recorded. Experiment 2: The device with feedback lead to a mean (standard error—SE) depth of 24.61 mm (0.99) compared with 20.08 mm (0.96) for the feedback disabled device. Analysis of covariance provided a mean significant difference (SE) of 4.52 mm (1.38 mm; p -value = 0.001) favoring the device with CPR rate feedback. Conclusions: CPR rate-only feedback was not detrimental to chest compression depth and suggests rate-only feedback may improve compression depth. Significance: The incorporation of clear, intuitive, audiovisual CPR feedback systems can assist lay-users to optimize compression rates and maintain a high CCF.

Automated Data Abstraction of Cardiopulmonary Resuscitation Process Measures for Complete Episodes of Cardiac Arrest Resuscitation.

Cardiopulmonary resuscitation (CPR) process measures research and quality assurance has traditionally been limited to the first 5 minutes of resuscitation due to significant costs in time, resources, and personnel from manual data abstraction. CPR performance may change over time during prolonged resuscitations, which represents a significant knowledge gap. Moreover, currently available commercial software output of CPR process measures are difficult to analyze. The objective was to develop and validate a software program to help automate the abstraction and transfer of CPR process measures data from electronic defibrillators for complete episodes of cardiac arrest resuscitation. We developed a software program to facilitate and help automate CPR data abstraction and transfer from electronic defibrillators for entire resuscitation episodes. Using an intermediary Extensible Markup Language export file, the automated software transfers CPR process measures data (electrocardiogram [ECG] number, CPR start time, number of ventilations, number of chest compressions, compression rate per minute, compression depth per minute, compression fraction, and end-tidal CO2 per minute). We performed an internal validation of the software program on 50 randomly selected cardiac arrest cases with resuscitation durations between 15 and 60 minutes. CPR process measures were manually abstracted and transferred independently by two trained data abstractors and by the automated software program, followed by manual interpretation of raw ECG tracings, treatment interventions, and patient events. Error rates and the time needed for data abstraction, transfer, and interpretation were measured for both manual and automated methods, compared to an additional independent reviewer. A total of 9,826 data points were each abstracted by the two abstractors and by the software program. Manual data abstraction resulted in a total of six errors (0.06%) compared to zero errors by the software program. The mean ± SD time measured per case for manual data abstraction was 20.3 ± 2.7 minutes compared to 5.3 ± 1.4 minutes using the software program (p = 0.003). We developed and validated an automated software program that efficiently abstracts and transfers CPR process measures data from electronic defibrillators for complete cardiac arrest episodes. This software will enable future cardiac arrest studies and quality assurance programs to evaluate the impact of CPR process measures during prolonged resuscitations.

Association between chest compression rates and clinical outcomes following in-hospital cardiac arrest at an academic tertiary hospital

AimsRecent guidelines for management of cardiac arrest recommend chest compression rates of 100–120 compressions/min. However, animal studies have found cardiac output to increase with rates up to 150 compressions/min. The objective of this study was to test the association between chest compression rates during cardiopulmonary resuscitation for in-hospital cardiac arrest (IHCA) and outcome. MethodsWe conducted a prospective observational study at a single academic medical center. Inclusion criteria: age≥18, IHCA, cardiopulmonary resuscitation performed. We analyzed chest compression rates measured by defibrillation electrodes, which recorded changes in thoracic impedance. The primary outcome was return of spontaneous circulation (ROSC). We used multivariable logistic regression to determine odds ratios for ROSC by chest compression rate categories (100–120, 121–140, >140 compressions/min), adjusted for chest compression fraction (proportion of time chest compressions provided) and other known predictors of outcome. We set 100–120 compressions/min as the reference category for the multivariable model. ResultsWe enrolled 222 consecutive patients and found a mean chest compression rate of 139±15. Overall 53% achieved ROSC; among 100–120, 121–140, and >140 compressions/min, ROSC was 29%, 64%, and 49% respectively. A chest compression rate of 121–140 compressions/min had the greatest likelihood of ROSC, odds ratio 4.48 (95% CI 1.42–14.14). ConclusionsIn this sample of adult IHCA patients, a chest compression rate of 121–140 compressions/min had the highest odds ratio of ROSC. Rates above the currently recommended 100–120 compressions/min may improve the chances of ROSC among IHCA patients.

Cardiopulmonary resuscitation quality and beyond: the need to improve real-time feedback and physiologic monitoring.

High-quality cardiopulmonary resuscitation (CPR) has been shown to improve survival outcomes after cardiac arrest. The current standard in studies evaluating CPR quality is to measure CPR process measures—for example, chest compression rate, depth, and fraction. Published studies evaluating CPR feedback devices have yielded mixed results. Newer approaches that seek to optimize CPR by measuring physiological endpoints during the resuscitation may lead to individualized patient care and improved patient outcomes.

An accurate method for real-time chest compression detection from the impedance signal

ObjectiveReal-time feedback improves CPR performance. Chest compression data may be obtained from an accelerometer/force sensor, but the impedance signal would serve as a less costly, universally available alternative. The objective is to assess the performance of a method which detects the presence/absence of chest compressions and derives CPR quality metrics from the impedance signal in real-time at 1s intervals without any latency period. MethodsDefibrillator recordings from cardiac arrest cases were divided into derivation (N=119) and validation (N=105) datasets. With the force signal as reference, the presence/absence of chest compressions in the impedance signal was manually annotated (reference standard). The method classified the impedance signal at 1s intervals as Chest Compressions Present, Chest Compressions Absent or Indeterminate. Accuracy, sensitivity and specificity for chest compression detection were calculated for each case. Differences between method and reference standard chest compression fractions and rates were calculated on a minute-to-minute basis. ResultsIn the validation set, median accuracy was 0.99 (IQR 0.98, 0.99) with 2% of 1s intervals classified as Indeterminate. Median sensitivity and specificity were 0.99 (IQR 0.98, 1.0) and 0.98 (IQR 0.95, 1.0), respectively. Median chest compression fraction error was 0.00 (IQR −0.01, 0.00), and median chest compression rate error was 1.8 (IQR 0.6, 3.3) compressions per minute. ConclusionA real-time method detected chest compressions from the impedance signal with high sensitivity and specificity and accurately estimated chest compression fraction and rate. Future investigation should evaluate whether an impedance-based guidance system can provide an acceptable alternative to an accelerometer-based system.

Why do some studies find that CPR fraction is not a predictor of survival?

IntroductionAn 80% chest compression fraction (CCF) during resuscitation is recommended. However, heterogeneous results in CCF studies were found during the 2015 Consensus on Science (CoS), which may be because chest compressions are stopped for a wide variety of reasons including providing lifesaving care, provider distraction, fatigue, confusion, and inability to perform lifesaving skills efficiently. ObjectiveThe effect of confounding variables on CCF to predict cardiac arrest survival. MethodsA secondary analysis of emergency medical services (EMS) treated out-of-hospital cardiac arrest (OHCA) patients who received manual compressions. CCF (percent of time patients received compressions) was determined from electronic defibrillator files. Two Sample Wilcoxon Rank Sum or regression determined a statistical association between CCF and age, gender, bystander CPR, public location, witnessed arrest, shockable rhythm, resuscitation duration, study site, and number of shocks. Univariate and multivariate logistic regressions were used to determine CCF effect on survival. ResultsOf 2132 patients with manual compressions 1997 had complete data. Shockable rhythm (p<0.001), public location (p<0.004), treatment duration (p<0.001), and number of shocks (p<0.001) were associated with lower CCF. Univariate logistic regression found that CCF was inversely associated with survival (OR 0.07; 95% CI 0.01–0.36). Multivariate regression controlling for factors associated with survival and/or CCF found that increasing CCF was associated with survival (OR 6.34; 95% CI 1.02–39.5). ConclusionCCF cannot be looked at in isolation as a predictor of survival, but in the context of other resuscitation activities. When controlling for the effects of other resuscitation activities, a higher CCF is predictive of survival. This may explain the heterogeneity of findings during the CoS review.

MP027: Automated cardiopulmonary resuscitation quality data abstraction for complete episodes of out-of-hospital cardiac arrest resuscitation

Introduction: Cardiopulmonary resuscitation (CPR) quality assurance and research has traditionally been limited to the first five minutes of resuscitation due to significant costs in time, resources and personnel from manual data abstraction. Moreover, CPR quality can be affected during prolonged resuscitations, which represents significant knowledge gaps. The objective of this study was to develop a software program to help automate the abstraction of CPR quality data from electronic defibrillators. Methods: We developed a software program to facilitate and help automate data abstraction from electronic defibrillator files for entire resuscitation episodes. Internal validation of the software program was performed on 50 randomly selected cardiac arrest cases with resuscitation durations of up to 60 minutes. CPR quality data variables such as number of ventilations, number of compressions, minute compression rate, minute compression depth, minute compression fraction, minute end-tidal CO2, were manually abstracted independently by two trained data abstractors and by the automated software program. Error rates and the time needed for data abstraction were measured. Results: A total of 9826 data points were abstracted. Manual data abstraction resulted in a total of six errors (0.06%) compared to zero errors by the software program. The mean time ± SD needed for manual data abstraction was 20.3 ± 2.7 minutes compared to 5.3 ± 1.4 minutes using the software program (p=0.003). Conclusion: Our CPR quality data abstraction software was 100% accurate in abstracting CPR quality data for complete resuscitation episodes and showed a significant reduction in data abstraction duration. This software will enable quality assurance programs and future cardiac arrest studies to evaluate the impact of CPR quality during prolonged resuscitations.

Chest Compression Fraction: A Time Dependent Variable of Survival in Shockable Out-of-hospital Cardiac Arrest: Cheskes S, Schmicker RH, Rea T, et al. Resuscitation. 2015;97:129-135.

Chest Compression Fraction: A Time Dependent Variable of Survival in Shockable Out-of-hospital Cardiac Arrest: Cheskes S, Schmicker RH, Rea T, et al. Resuscitation. 2015;97:129-135.

Research progress of prognosis and recognition methods for return of spontaneous circulation during cardiopulmonary resuscitation

Cardiopulmonary resuscitation is the most commonly used method facing cardiac arrest. The 2010 CPR guidelines emphasized high quality chest compressions and recommended continuous compression for 2 minutes after defibrillation to minimize interruptions in compressions. However, starting chest compressions immediately after a defibrillation shock may be harmful, if the heart is providing spontaneous beats and being subjected to external compressions at the same time. So it is very important to recognize ROSC during CPR, the methods of which include touching the pulse, amplitude spectral area, partial pressure end-tidal carbon dioxide, coronary perfusion pressure, central venous oxygen saturation, chest compression fraction, regional cerebral oxygen saturation, photoplethysmography, conjunctival oxygen tension, transthoracic-impedance plethysmography and echocardiography. This paper gives a review of the ROSC prognosis and recognition methods during CPR. Key words: Cardiopulmonary resuscitation; Return of spontaneous circulation; Prognosis; Recognition; Progress

Abstract 17064: The Accuracy of an Impedance Cardiogram Based Compression Rate Feedback Algorithm Versus Real-time Video Recording of Chest Compression Rate

Objective: It is widely known that CPR administered in all settings may be sub-optimal. CPR feedback tools can provide reliable feedback to operators to improve compression rate, depth and fraction. The purpose of this study was to evaluate the use of a CPR rate feedback algorithm incorporated into an automated external defibrillator by comparing the CPR compression rate measured by an Impedance Cardiogram based feedback device, a video recording of real-time CPR and using a commercially available accelerometer Hypothesis: ICG based CPR feedback is as effective as accelerometer based feedback. Methods: A total of twelve porcine models were used each weighing 29.62±4.2kg. Rate (CPM), End-tidal CO 2 (ETCO 2 ), Blood Pressure (BP), SpO2 (%) and Depth (mm) was measured for each model. The Impedance Cardiogram (ICG)/Thoracic Impedance was recorded via 2 standard defibrillation electrodes and as a method of detecting the presence of CPR. Ethical approval was granted by the Northern Ireland Home Office and the Home Office in Scotland. Models were anaesthetised using Propofol and Isoflurane and connected to a Datex Ohmeda ® monitor for anaesthesia monitoring. A number of physiological measurements were taken every 2 minutes via the carotid and jugular. Rate and depth were measured continuously using Q-CPR ® , Philips. Recordings from each experiment were acquired using Datex Ohmeda review software for further statistical analysis using SAS 9.2 ® . Findings: The proportion of correct audio and visual feedback of the Impedance Cardiogram based feedback device versus the actual CPR compression rate as demonstrated in video recordings was 95.2%. The study also showed that the proportion of “correct” audio and visual feedback of the SAM 450P CPR Rate Feedback algorithm versus the accelerometer rate (CPM) was 87.5% due to underestimation of some measures in the non-ICG based device. Conclusions: Therefore it could be concluded that an Impedance Cardiogram based feedback device is highly sensitive to end user chest compression rate over a wide range of rates (40 to 180 compressions-per-minute).

Abstract 17679: Automating Cardiopulmonary Resuscitation Quality Data Abstraction for Entire Episodes of Cardiac Arrest Resuscitation

Introduction: Research and quality assessment of cardiopulmonary resuscitation (CPR) quality has traditionally been limited to the first five minutes of resuscitation due to significant costs in both time and personnel from manual data abstraction. Manual CPR quality data abstraction of entire episodes of resuscitation may be too resource-intensive for many emergency medical service (EMS) agencies and hospitals. Moreover, the first five minutes of CPR are also different in many aspects compared to later time periods during cardiac arrest resuscitation, which represents significant knowledge gaps since the majority of resuscitations go beyond five minutes. Methods: We developed a software program to facilitate and help automate data abstraction from electronic defibrillator files for entire resuscitation episodes. Internal validation of the software program was performed on 50 randomly selected out-of-hospital cardiac arrest cases with resuscitation durations up to 60 minutes. CPR quality data variables were abstracted as minute averages, which included ventilation rate, CPR compression rate, depth, fraction, and end-tidal CO2. CPR quality data variables were manually abstracted independently by two trained data abstractors and automatically by the software program. Error rates and the time needed for data abstraction were measured. Results: A total of 9826 data points were abstracted. Manual data abstraction resulted in a total of six errors (0.06%) compared to zero errors by the software program. The mean time ± SD needed for data abstraction was 20.3 ± 2.7 minutes manually and 5.3 ± 1.4 minutes using the software program (p=0.003). Conclusion: Our data abstraction software was 100% accurate in abstracting CPR quality data for complete cardiac arrest resuscitation episodes. It significantly reduced the time and resources required to abstract CPR quality data, and will allow EMS agencies and hospitals to evaluate their CPR quality in a cost-effective manner. The development of this software will enable future studies to efficiently evaluate CPR quality during entire resuscitation episodes, including its impact on patient outcomes during prolonged cardiac arrests.

Abstract 17062: Can Automated Rate-only CPR Feedback be Detrimental to Chest Compression Depth? A CPR Simulation Study of 141 Untrained Operators

Introduction: A number of public access defibrillators incorporate computerised audio-visual feedback mechanisms to help responders deliver cardiopulmonary resuscitation (CPR) according to current guidelines. A 2013 American Heart Association statement suggested that chest compression fraction (CCF) and compression rate should be prioritised over compression depth, chest recoil and ventilations. This usability study assessed the effect of real-time rate-only feedback on chest compression depth. Methods: Randomly selected users were recruited in a shopping mall (n=141; 15-65+ years) to deliver CPR using a public access defibrillator in a simulated scenario. Participants were randomly assigned one of two devices - (1) with CPR rate feedback in the form of a machine-interface comprising of audio-voice prompts and light emitting diodes; (2) without CPR feedback. Participants were instructed to turn on the device and follow the prompts, with no information on how to perform CPR provided. CPR rate and depth were captured by measuring displacement of a potentiometer contained in a specially designed manikin. The device was connected to the manikin via the electrode leads. The effect of rate-only feedback on compression depth and CPR fraction were assessed. Results: ANCOVA analysis between the two devices provided a mean difference (Standard Error; SE) of 4.52mm (1.38mm) indicating a statistically significant difference (p-value=0.001) between measured CPR depth favouring the device with CPR rate feedback. There was no significant difference in CCF between the devices. ANCOVA analysis provided a mean difference (SE) of 2.9% (1.9%) for the device with CPR rate feedback compared to the device without CPR rate feedback. Conclusion: The incorporation of clear, intuitive, audio-visual machine-interface that delivers CPR feedback can assist trained and untrained users in the optimisation of chest compression rate and maintain a high CCF. In conclusion, CPR rate-only feedback was not detrimental to chest compression depth and suggests rate-only feedback may improve compression depth.

Compression fraction and basic airway management skills in young military personnel on two different levels of life support training

s / Resuscitation 96S (2015) 43–157 55 Conclusions: The multidimensional bundle may significantly improve dispatcher recognition of OHCA and enhance DA-BCPR. Those enhancement may result majorly from the bystanders unaware of doingCPR that increase call diversion toCPR instruction and chest compressions delivery rather than from those already aware of CPR. http://dx.doi.org/10.1016/j.resuscitation.2015.09.126

Association of advanced airway device with chest compression fraction during out-of-hospital cardiopulmonary arrest

BackgroundSelect Emergency Medical Services (EMS) practitioners substitute endotracheal intubation (ETI) with supraglottic airway (SGA) insertion to minimize CPR chest compression interruptions, but the resulting effects upon chest compression fraction (CCF) are unknown. We sought to determine the differences in CCF between adult out-of-hospital cardiac arrest (OHCA) receiving ETI and those receiving SGA. MethodsWe studied adult, non-traumatic OHCA patients enrolled in the Resuscitation Outcomes Consortium (ROC) Prehospital Resuscitation using an Impedance valve and an Early vs. Delayed analysis (PRIMED) trial. Chest compressions were measured using compression or thoracic impedance sensors. We limited the analysis to those receiving ETI or SGA (Combitube, King Laryngeal Tube, or Laryngeal Mask Airway) and >2min of chest compression data before and after airway insertion. We compared CCF between ETI and SGA before and after airway insertion, adjusting for age, sex, witnessed arrest, bystander CPR, shockable initial rhythm, public location, PRIMED trial arm, and regional ROC center. We also compared the change in CCF for each airway technique. ResultsOf 14,955 patients enrolled in the ROC PRIMED trial, we analyzed 2767 cases, including 2051 ETI, 671 SGA, and 45 both. Among subjects in this investigation the mean age was 66.4 years with a male predominace, 46% with witnessed event, 37% receiving bystander CPR, and 22% presenting with an initially shockable rhythm. Pre- and post-airway CCF was higher for SGA than ETI (SGA pre-airway CCF 73.2% [95%CI: 71.6–74.7%] vs. ETI 70.6% [95%CI: 69.7–71.5%]; post-airway 76.7% [95%CI: 75.2–78.1%] vs. 72.4% [95%CI: 71.5–73.3%]). After adjusting for potential confounders, these significant changes persisted (pre-airway difference 2.2% favoring SGA, p-value=0.046; post-airway 3.4% favoring SGA, p=0.001). ConclusionIn patients with OHCA, we detected a slightly higher rate of CCF in patients for whom a SGA was inserted, both before and after insertion. However, the actual differences were so small, that in the context of this observational, secondary analysis, it is unclear if this represents a clinically significant difference.

Comparison Between 30:1 and 30:2 Compression-to-ventilation Ratios for Cardiopulmonary Resuscitation: Are Two Ventilations Necessary?

Controversy is continuing over the need for ventilation and the optimal compression-ventilation (CV) ratio during cardiopulmonary resuscitation (CPR). The aim of this study was to comparatively elucidate the effect on hemodynamics and arterial oxygen saturation of a single ventilation relative to two consecutive ventilations during CPR in a dog model of cardiac arrest. Twenty mongrel dogs were divided into two groups. After 3 minutes of ventricular fibrillation (VF), the single-ventilation group received CPR with a 30:1 CV ratio, and the two-ventilation group received CPR with a 30:2 CV ratio, all with room air for 7 minutes. Thereafter, continuous chest compressions and intermittent ventilation at rate of 10 per minute were followed for both groups for 10 minutes. Hemodynamic parameters, arterial blood gas profiles, and variables from CPR were compared at baseline and at 5, 10, 15, and 20 minutes after induction of VF. Hemodynamic parameters including aortic systolic and diastolic pressures, right atrial systolic and diastolic pressures, coronary perfusion pressure, end-tidal carbon dioxide tension, and arterial blood gas profiles including arterial oxygen tension, arterial oxygen saturation, and arterial carbon dioxide tension were not different between two groups during CPR. In the 30:1 group, the period of compression interruption was shorter and chest compression fraction was higher than that in the 30:2 group (6 sec/min vs. 10.9 sec/min, p < 0.001; 90.0% vs. 81.8%, p < 0.001). CPR with a 30:1 CV ratio, compared to CPR with a 30:2 CV ratio, results in comparable arterial oxygenation saturation and hemodynamics.