Instructions to "push as hard as you can" improve average chest compression depth in dispatcher-assisted cardiopulmonary resuscitation.
ABSTRACT: BACKGROUND AND OBJECTIVE:Cardiopulmonary resuscitation (CPR) with adequate chest compression depth appears to improve first shock success in cardiac arrest. We evaluate the effect of simplification of chest compression instructions on compression depth in dispatcher-assisted CPR protocol. METHODS:Data from two randomized, double-blinded, controlled trials with identical methodology were combined to obtain 332 records for this analysis. Subjects were randomized to either modified Medical Priority Dispatch System (MPDS) v11.2 protocol or a new simplified protocol. The main difference between the protocols was the instruction to "push as hard as you can" in the simplified protocol, compared to "push down firmly 2in. (5cm)" in MPDS. Data were recorded via a Laerdal ResusciAnne SkillReporter manikin. Primary outcome measures included: chest compression depth, proportion of compressions without error, with adequate depth and with total release. RESULTS:Instructions to "push as hard as you can", compared to "push down firmly 2in. (5cm)", resulted in improved chest compression depth (36.4 mm vs. 29.7 mm, p<0.0001), and improved median proportion of chest compressions done to the correct depth (32% vs. <1%, p<0.0001). No significant difference in median proportion of compressions with total release (100% for both) and average compression rate (99.7 min(-1) vs. 97.5 min(-1), p<0.56) was found. CONCLUSIONS:Modifying dispatcher-assisted CPR instructions by changing "push down firmly 2in. (5cm)" to "push as hard as you can" achieved improvement in chest compression depth at no cost to total release or average chest compression rate.
Project description: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.
Project description:Basic Cardiac Life Support (BCLS) or cardiopulmonary resuscitation (CPR) refers to the skills required (without use of equipment) in the resuscitation of cardiac arrest individuals. On recognising cardiac arrest, chest compressions should be initiated. Good quality compressions are with arms extended, elbows locked, shoulders directly over the casualty's chest and heel of the palm on the lower half of the sternum. The rescuer pushes hard and fast, compressing 4-6 cm deep for adults at 100-120 compressions per minute with complete chest recoil. Two quick mouth-to-mouth ventilations (each 400-600 mL tidal volume) should be delivered after every 30 chest compressions. Chest compression-only CPR is recommended for lay rescuers, dispatcher-assisted CPR and those unable or unwilling to give ventilations. CPR should be stopped when the casualty wakes up, an emergency team takes over casualty care or if an automated external defibrillator prompts for analysis of heart rhythm or delivery of shock.
Project description:Background:The Nuss procedure temporarily places intrathoracic bars for repair of pectus excavatum (PE). The bars may impact excursion and compliance of the anterior chest wall while in place. Effective chest compressions during cardiopulmonary resuscitation (CPR) require depressing the anterior chest wall enough to compress the heart between sternum and spine. We assessed the force required to perform the American Heart Association's recommended chest compression depth after Nuss repair. Methods:A lumped element elastic model was developed to simulate the relationship between chest compression forces and displacement with focus on the amount of force required to achieve a depth of 5 cm in the presence of 1-3 Nuss bars. Literature review was conducted for evidence supporting potential use of active abdominal compressions and decompression (AACD) as an alternative method of CPR. Results:The presence of bars notably lowered compression depth by a minimum of 69% compared to a chest without bar(s). The model also demonstrated a dramatic increase (minimum of 226%) in compressive forces required to achieve recommended 5 cm depth. Literature review suggests AACD could be an alternative CPR in patients with Nuss bar(s). Conclusions:In our model, Nuss bars limited the ability to perform chest compressions due to increased force required to achieve a 5 cm compression. The greater the number of Nuss bars present the greater the force required. This may prevent effective CPR. Use of active abdominal compressions and decompressions should be studied further as an alternative resuscitation modality for patients after the Nuss procedure.
Project description:BACKGROUND:Current guidelines underline the importance of high-quality chest compression during cardiopulmonary resuscitation (CPR), to improve outcomes. Contrary to this many studies show that chest compression is often carried out poorly in clinical practice, and long interruptions in compression are observed. This prospective cohort study aimed to analyse whether chest compression quality changes when a real-time feedback system is used to provide simultaneous audiovisual feedback on chest compression quality. For this purpose, pauses in compression, compression frequency and compression depth were compared. METHODS:The study included 292 out-of-hospital cardiac arrests in three consecutive study groups: first group, conventional resuscitation (no-sensor CPR); second group, using a feedback sensor to collect compression depth data without real-time feedback (sensor-only CPR); and third group, with real-time feedback on compression quality (sensor-feedback CPR). Pauses and frequency were analysed using compression artefacts on electrocardiography, and compression depth was measured using the feedback sensor. With this data, various parameters were determined in order to be able to compare the chest compression quality between the three consecutive groups. RESULTS:The compression fraction increased with sensor-only CPR (group 2) in comparison with no-sensor CPR (group 1) (80.1% vs. 87.49%; P < 0.001), but there were no further differences belonging compression fraction after activation of sensor-feedback CPR (group 3) (P = 1.00). Compression frequency declined over the three study groups, reaching the guideline recommendations (127.81 comp/min vs. 122.96 comp/min, P = 0.02 vs. 119.15 comp/min, P = 0.008) after activation of sensor-feedback CPR (group 3). Mean compression depth only changed minimally with sensor-feedback (52.49 mm vs. 54.66 mm; P = 0.16), but the fraction of compressions with sufficient depth (at least 5 cm) and compressions within the recommended 5-6 cm increased significantly with sensor-feedback CPR (56.90% vs. 71.03%; P = 0.003 and 28.74% vs. 43.97%; P < 0.001). CONCLUSIONS:The real-time feedback system improved chest compression quality regarding pauses in compression and compression frequency and facilitated compliance with the guideline recommendations. Compression depth did not change significantly after activation of the real-time feedback. Even the sole use of a CPR-feedback-sensor ("sensor-only CPR") improved performance regarding pauses in compression and compression frequency, a phenomenon known as the 'Hawthorne effect'. Based on this data real-time feedback systems can be expected to raise the quality level in some parts of chest compression quality. TRIAL REGISTRATION:International Clinical Trials Registry Platform of the World Health Organisation and German Register of Clinical Trials (DRKS00009903), Registered 09 February 2016 (retrospectively registered).
Project description:BACKGROUND:Quality of cardiopulmonary resuscitation (CPR) is key to increase survival from cardiac arrest. Providing chest compressions with adequate rate and depth is difficult even for well-trained rescuers. The use of real-time feedback devices is intended to contribute to enhance chest compression quality. These devices are typically based on the double integration of the acceleration to obtain the chest displacement during compressions. The integration process is inherently unstable and leads to important errors unless boundary conditions are applied for each compression cycle. Commercial solutions use additional reference signals to establish these conditions, requiring additional sensors. Our aim was to study the accuracy of three methods based solely on the acceleration signal to provide feedback on the compression rate and depth. MATERIALS AND METHODS:We simulated a CPR scenario with several volunteers grouped in couples providing chest compressions on a resuscitation manikin. Different target rates (80, 100, 120, and 140 compressions per minute) and a target depth of at least 50 mm were indicated. The manikin was equipped with a displacement sensor. The accelerometer was placed between the rescuer's hands and the manikin's chest. We designed three alternatives to direct integration based on different principles (linear filtering, analysis of velocity, and spectral analysis of acceleration). We evaluated their accuracy by comparing the estimated depth and rate with the values obtained from the reference displacement sensor. RESULTS:The median (IQR) percent error was 5.9% (2.8-10.3), 6.3% (2.9-11.3), and 2.5% (1.2-4.4) for depth and 1.7% (0.0-2.3), 0.0% (0.0-2.0), and 0.9% (0.4-1.6) for rate, respectively. Depth accuracy depended on the target rate (p < 0.001) and on the rescuer couple (p < 0.001) within each method. CONCLUSIONS:Accurate feedback on chest compression depth and rate during CPR is possible using exclusively the chest acceleration signal. The algorithm based on spectral analysis showed the best performance. Despite these encouraging results, further research should be conducted to asses the performance of these algorithms with clinical data.
Project description:A 2-year-old boy found in cardiac arrest secondary to drowning received standard CPR for 35 minutes and was transported to a tertiary hospital for rewarming from hypothermia. Chest compressions in hospital were started using two-thumb encircling hands technique. Subsequently two-thumbs direct sternal compression technique and after sternal force/depth sensor placement, chest compression with classic one-hand technique were done. By using CPR recording/feedback defibrillator, quantitative CPR quality data and invasive arterial pressures were available for analyses for 5 hours and 35 minutes. 316 compressions with the two-thumb encircling hands technique provided a mean (SD) systolic arterial pressure (SAP) of 24 (4) mmHg, mean arterial pressure (MAP) 18 (3) and diastolic arterial pressure (DAP) of 15 (3) mmHg. ~6000 compressions with the two thumbs direct compression technique created a mean SAP of 45 (7) mmHg, MAP 35 (4) mmHg and DAP of 30 (3) mmHg. ~20,000 compressions with the sternal accelerometer in place produced SAP 50 (10) mmHg, MAP 32 (5) mmHg and DAP 24 (4) mmHg. Restoration of spontaneous circulation (ROSC) was achieved at the point when the child achieved normothermia by using peritoneal dialysis. Unfortunately, the child died ten hours after ROSC without any signs of neurological recovery. This case demonstrates improved hemodynamic parameters with classic one-handed technique with real-time quantitative quality of CPR feedback compared to either the two-thumbs encircling hands or two-thumbs direct sternal compression techniques. We speculate that the improved arterial pressures were related to improved chest compression depth when a real-time CPR recording/feedback device was deployed.ClinicalTrials.gov: NCT00951704.
Project description:<h4>Background</h4>The 2005 Emergency Cardiac Care guidelines for basic life support (BLS) recommend compression to ventilation ratio of 30:2. The effect of the additional exertion required to deliver more chest compressions may present a considerable physical burden on the provider.<h4>Objective</h4>To compare cardiopulmonary resuscitation (CPR) performance and perceived exertion during compression to ventilation ratios of 15:2 and 30:2 with real-time feedback during two-rescuer CPR.<h4>Methods</h4>Eighteen BLS-certified healthcare providers each performed 5 min of chest compressions on a manikin with compression to ventilation ratios of 15:2 or 30:2 on two separate sessions. Heart rate, capillary lactate, and OMNI rate of perceived exertion (RPE) were recorded before and after each session. Subjects were given continuous, automated, feedback via an accelerometer that measured rate, depth, duration, and release of compressions. Compression measurements and feedback messages were recorded continuously during each 5-min session. Data were analyzed using descriptive statistics and t-test to compare groups. Repeated measures ANOVA were used to compare data over the 5-min epoch.<h4>Results</h4>After performing external chest compressions for 5 min, peak heart rate (102+/-24 vs. 106+/-27), capillary lactate (2.2+/-0.95 vs. 2.2+/-0.96), and OMNI RPE (4.3+/-1.2 vs. 4.6+/-1.1) were higher were higher than baseline, but did not differ between 15:2 and 30:2. Compression rate (102+/-24 vs.106+/-27) and depth (38.8+/-3.6 vs. 38.2+/-2.9) did not differ between 15:2 and 30:2 groups or at any minute. Total chest compressions delivered were higher (p<0.05) in the 30:2 group (457+/-43) compared to 15:2 (379+/-28). The average no flow time was lower (p<0.05) in the 30:2 group (22+/-3.03) compared to the 15:2 group (33+/-2.64). Number of correction prompts (48+/-55 vs. 64+/-70) did not differ significantly between the 15:2 and 30:2 groups.<h4>Conclusions</h4>In a cohort of healthcare providers, increasing the CPR ratio from 15:2 to 30:2 did not change physical or perceived exertion during a 5-min bout of CPR when continuous, real-time feedback is provided. The 30:2 compression to ventilation ratio resulted in more chest compressions per minute without decreasing CPR quality.
Project description:BACKGROUND:If transport under ongoing cardiopulmonary resuscitation (CPR) from an upper floor is indicated, the ideal CPR-method and evacuation route is unknown hitherto. We aimed to elaborate a strategy for evacuation of patients under ongoing CPR from an upper floor, comparing three different evacuation routes and manual and mechanical chest compressions. METHODS:A CPR-training manikin recording CPR-quality was placed on the fifth floor and was evacuated to an ambulance via lift, turntable ladder, or staircase. Chest compressions were performed manually or with a mechanical CPR-device. Efficiency endpoints were compression depth and frequency, sufficiency of chest release, compared with European Resuscitation Council (ERC) Guidelines, and duration of the evacuation. Adverse outcomes were disconnection/dislocation of devices and hazards/accidents to the personnel. RESULTS:For all evacuation routes, compression depth and frequency were significantly more compliant with ERC-guidelines under mechanical CPR. Manual CPR was associated with considerable deviations from correct compression depth and frequency. Chest release only slightly differed between groups. Evacuation via lift under mechanical CPR was fastest and evacuation via turntable ladder under manual CPR was slowest. No device disconnections or accidents occurred, but hazard to personnel was perceived during evacuation via ladder under manual CPR. CONCLUSIONS:In this study, a mechanical CPR-device proved to deliver better CPR-quality during evacuation from an upper floor. If a lift accessible with a stretcher is available, this route should be preferred, regardless of manual or mechanical CPR. Turntable ladders can only be meaningfully used with mechanical CPR, otherwise CPR-quality is poor and hazard to the personnel is increased. Not all evacuation routes may be useable in a specific real-life scenario. TRIAL REGISTRATION:German Clinical Trials Registry, www.drks.de, registration number DRKS00012885, registration date 17.08.2017.
Project description:When a cardiac arrest occurs, it is necessary to perform cardiopulmonary resuscitation (CPR) as soon as possible. This requires maintaining the pressure depth at 5 cm at a rate of 100 cpm. For CPR machines, which are frequently used in ambulances, the return of spontaneous circulation (ROSC) is not superior to that of manual CPR, although CPR machines can maintain the compression rate and reciprocal distance of the compression plate more accurately. When the thoracic cavity is deformed due to repeated chest compressions, CPR machines must be adjusted. It is necessary to develop a method for measuring whether adequate CPR is achieved using CPR machines. CPR was performed on two pigs with a CPR machine, commencing 1 minute after the heart was stopped. Four CPR modes were used, with compression rates of 60 or 100 cpm and compression depths of 3 or 5 cm. The CPR machine was equipped with a load cell for measuring compression force, and a potentiometer for measuring compression depth. The measurement results obtained from the sensor were used to calculate the frequency components. The compression force and depth data were used to calculate the mechanical power of the CPR machine and mechanical impedance of the thoracic cavity. Changes in end-tidal carbon dioxide (ETCO2), coronary perfusion pressure (CPP), carotid blood flow (CBF), and right atrial pressure (RAP) were measured during performance of CPR; change in RAP refers to variation therein with chest compressions. Continuous CPR in both animals resulted in deformation of the chest cavity and a steady decline in impedance. The correlation between CPR power and change in RAP was 0.78, and that between compression force and CBF was 0.64. Impedance was not correlated with blood pressure or CBF. When the condition of the animal deteriorated due to cardiac arrest, the CPP decreased and ETCO2 increased. The CPR power and RAP varied according to the CPR mode rather than the condition of the animal. Measuring the CPR machine power does not require a separate procedure, such as catheter intubation, so should be suitable as an index of the quality of CPR in emergency situations.
Project description:This article is a companion to a systematic review, entitled, Associations between cardiopulmonary resuscitation (CPR) knowledge, self-efficacy, training history and willingness to perform CPR and CPR psychomotor skills: a systematic review (Riggs et al., 2019). The data tables described in this article summarise the impact that specific training interventions, number of times trained, and retention testing intervals have on laypeople's CPR psychomotor skills, as reported by peer-reviewed journal articles. The psychomotor skills included are: compression rate, compression depth, duration of interruptions to compressions, chest recoil, hand placement, proportion of adequate or 'correct' compressions, ventilation volume, compression-to-ventilation ratio, duty cycle and overall skills. The data tables described in this article are available as a supplementary file to this article.