Hands-off Time Research Articles

Drone-delivered automated external defibrillators for out-of-hospital cardiac arrest: A simulation-based feasibility study

Background Cardiopulmonary resuscitation (CPR) and defibrillation markedly increases survival following out-of-hospital cardiac arrest (OHCA). Members of the public can perform both before the ambulance service arrives. However, bystanders use a public-access Automated External Defibrillator (AED) in around 5% of cases. Using Unmanned Aerial Vehicles (‘drones’) to deliver AEDs may overcome many of the barriers preventing public-access AED use. The study team investigated how quickly and easily bystanders performing CPR could use drone-delivered AEDs. Methods The study team developed an AED-capable drone between May and November 2020 and conducted 18 OHCA simulations in July and September 2021. A single participant found a simulated patient inside a building and made a 999-call to a Welsh Ambulance Services NHS Trust call-handler. Once cardiac arrest was confirmed during the 999-call a nearby drone launched, reached hovering altitude and delivered the AED immediately outside the building. The participant retrieved the AED when instructed to do so, attached it to the patient and delivered a single shock. The primary outcome was hands-off CPR time. Secondary outcomes included ease of AED retrieval, by using a questionnaire adapted from the System Usability Scale and exploring participant behaviours via post-simulation interviews and reviews of audio and video recordings of the simulation. Results Hands-off CPR time was (median) 109 s (interquartile range 87–130 s). Participants spent 19 s (16–22 s) away from the patient's side when retrieving the AED. Participants found it easy to use the AED but often sought the call-handler's reassurance that it was appropriate to retrieve it. Conclusion Participants found it easy to retrieve and use an AED delivered by drone in simulated OHCAs. Hands-off CPR time was potentially clinically relevant in this lone bystander simulation, but there was only a small increase in hands-off time caused by retrieval of the drone-delivered AED.

Automated Nanodroplet Dispensing for Large-Scale Spheroid Generation via Hanging Drop and Parallelized Lossless Spheroid Harvesting.

Creating model systems that replicate in vivo tissues is crucial for understanding complex biological pathways like drug response and disease progression. Three-dimensional (3D) in vitro models, especially multicellular spheroids (MCSs), offer valuable insights into physiological processes. However, generating MCSs at scale with consistent properties and efficiently recovering them pose challenges. We introduce a workflow that automates large-scale spheroid production and enables parallel harvesting into individual wells of a microtiter plate. Our method, based on the hanging-drop technique, utilizes a non-contact dispenser for dispensing nanoliter droplets of a uniformly mixed-cell suspension. The setup allows for extended processing times of up to 45 min without compromising spheroid quality. As a proof of concept, we achieved a 99.3% spheroid generation efficiency and maintained highly consistent spheroid sizes, with a coefficient of variance below 8% for MCF7 spheroids. Our centrifugation-based drop transfer for spheroid harvesting achieved a sample recovery of 100%. We successfully transferred HT29 spheroids from hanging drops to individual wells preloaded with collagen matrices, where they continued to proliferate. This high-throughput workflow opens new possibilities for prolonged spheroid cultivation, advanced downstream assays, and increased hands-off time in complex 3D cell culture protocols.

Comparison Between the Advanced Cardiac Life Support and Adult Advanced Life Support Protocols: A Simulation-Based Pilot Study.

Introduction: Cardiac arrest is a public health concern associated with unfavorable disease outcomes. Cardiopulmonary resuscitation (CPR) of optimal quality is widely acknowledged as an indispensable technique in restoring spontaneous circulation. In order to perform advanced cardiac life support (ACLS), chest compression must be paused twice: once to assess the rhythm and again to administer the shock. Australian advanced life support (ALS) recommends that the defibrillator needs to be precharged in order to administer the shock during a solitary interval in chest compressions. While performing chest compressions, precharging defibrillators can decrease hands-off time without posing a risk of injury. Aim: To compare chest compression fraction (CCF)-which is the cumulative time spent providing chest compressions divided by the total time taken for the entire resuscitation-by calculating the hands-off time duration in cardiac arrest between the Australian Resuscitation Council (ARC) and American Heart Association (AHA) protocols for CPR. Methods: A simulation-based pilot study was designed using a Laerdal Resusci Anne mannequin and a LIFEPACK 20 defibrillator. The study included six participants recruited from King Khalid University Hospital in Riyadh, Saudi Arabia, where three participants were certified ACLS providers and there were certified ALS providers. Participants were divided into two groups, ALS and ACLS, each following one protocol. For each scenario, a random job was assigned to each participant, regardless of their role as assistant, team leader, or performer of CPR. Each case's shockable and nonshockable rhythms were hidden from the team leader and the chest compressor. Ten trials of CPR were performed, each for four cycles with a total time of 8 min. The simulation was video recorded for hands-off time counting. Comparison between CCF (seconds) per cycle between the two protocols was performed using an independent sample t-test. A p value of 0.05 was used to measure statistical significance. Results: Comparing CCF in shockable rhythms between ARC and AHA protocols, it was observed that the CCF of ALS-ARC was significantly higher than ACLS-AHA in all cycles; the first cycle: t = 3.782, p=0.004; the second cycle: t = 3.380, p=0.007; the third cycle: t = 3.803, p=0.003; and the fourth cycle: t = 4.341, p=0.001. Conclusion: Precharging a defibrillator before a rhythm check during chest compression, in anticipation of a potentially shockable rhythm, reduces the time required for defibrillation and limits interruptions in chest compression during CPR. This practice effectively enhances the CCF. Enhancing the continuity of chest compressions can potentially improve survival rates in ARC.

Live stream of prehospital point-of-care ultrasound during cardiopulmonary resuscitation – A feasibility trial

BackgroundCurrent resuscitation guidelines recommend that skilled persons could use ultrasound to detect reversible causes during cardiopulmonary resuscitation (CPR) where the examination can be safely integrated into the Advanced Life Support (ALS) algorithm. However, in a prehospital setting performing and rapidly interpreting ultrasound can be challenging for physicians. Implementing remote, expert-guided, and real-time transmissions of ultrasound examinations offers the opportunity for tele-support, even during an out-of-hospital cardiac arrest (OHCA). The aim of this feasibility study was to evaluate the impact of tele-supported ultrasound in ALS on hands-off time during an OHCA. MethodsIn an urban setting, physicians performed point-of-care ultrasound (POCUS) on patients during OHCA using a portable device, either with tele-support (n = 30) or without tele-support (n = 12). Where tele-support was used, the ultrasound image was transmitted via a remote real-time connection to an on-call specialist in anaesthesia and intensive care medicine with an advanced level of critical care ultrasound expertise. The primary safety endpoint of this study was to evaluate whether POCUS can be safely integrated into the algorithm, and to provide an analysis of hands-off time before, during, and after POCUS during OHCA. ResultsIn all 42 cases it was possible to perform POCUS during regular rhythm analyses, and no additional hands-off time was required. In 40 of these 42 cases, the physicians were able to perform POCUS during a single regular rhythm analysis, with two periods required only in two cases. The median hands-off time during these rhythm analyses for POCUS with tele-support was 10 (8–13) seconds, and 11 (9–14) seconds for POCUS without tele-support. Furthermore, as a result of POCUS, in a quarter of all cases the physician on scene altered their diagnosis of the primary suspected cause of cardiac arrest, leading to a change in treatment strategy. ConclusionsThis feasibility study demonstrated that POCUS with tele-support can be safely performed during OHCA in an urban environment.Trial Registration (before patient enrolment): ClinicalTrials.gov, NCT04817475.

Comparing the effects of blended learning and traditional instruction on basic life support for laypersons: A randomized controlled trial

Background/purposeBlended learning offers the advantages of both instructor-led and self-instruction methods in basic life support (BLS). Our study aims to compare the effects of blended learning with those of traditional instructor-led methods on the performance of laypersons taking BLS courses. MethodsA total of 108 participants were randomly assigned to three groups: traditional instruction (group A, n = 36), blended learning with two rounds of practice (group B, n = 36), and blended learning with three rounds of practice (group C, n = 36). Group A received a 90-min lecture and a 30-min hands-on practice session using a manikin and a metronome. Participants in groups B and C received 18-min standardized online video lessons and performed hands-on practice twice and thrice, respectively. The primary outcome was chest compression at a correct speed (100–120 compressions per min) after the training course. Secondary outcomes included knowledge test scores, attitudes and confidence, and individual skill performance after training. ResultsPatient characteristics were similar between the groups. Blended learning with practicing thrice resulted in the highest compressions at a correct speed (group A vs. B vs. C, 68.09 vs 80.03 vs 89.42, p = 0.015) and the shortest average hands-off time (group A vs. B vs. C, 1.12 vs 0.86 vs 0.17 s, p = 0.015). Both blended groups performed better in confirming environmental safety (p < 0.001). No differences in scores of the knowledge test, attitude, or confidence were noted among the three groups. ConclusionBlended learning with three rounds of hands-on practice may be considered an alternative teaching method.

Simulation-based Comparison of British and Australian Advanced Life Support Guidelines.

Cardiac arrest is a major health concern that has been linked to poor disease outcomes. Cardiopulmonary resuscitation (CPR) is a critical protocol for restoring spontaneous circulation. The guidelines used by medical staff differ across different countries. A comparison of these guidelines can help in designing more efficient Advanced Life Support (ALS) protocols. The goal in this study was to compare the guidelines for interruption of compression during CPR (hands-off time) for ALS protocols provided by Australian and United Kingdom (UK) resuscitation councils. The author designed a simulation-based study using a mannequin and a defibrillator, and then recruited six participants. Three participants were certified ALS practitioners who followed UK guidelines, and three were certified ALS practitioners who followed Australian guidelines. Each participant received a random task assignment for each scenario, as a team leader, performer of cardiopulmonary resuscitation, or assistant. The team leader and the chest compressor were unaware of the shockability of each case's rhythm. Eight minutes total were spent on 10 CPR trials, each lasting four cycles. A video of the simulation was recorded for automated timekeeping. An independent sample t-test was used to compare the amount of hands-off time (seconds) throughout each cycle between two procedures. For purposes of calculating statistical significance, a 0.05 P-value was employed. The mean duration of second cycle hands-off time (seconds) in the UK ALS protocol was statistically significantly longer than the Australian ALS (t = -2.100; P = 0.05). For shockable rhythms, the hands-off time of the UK ALS protocol was significantly longer than Australian ALS protocol, as reflected in the second cycle (t = -0.621; P < 0.001), third cycle (t = -8.083; P < 0.001), and fourth cycle (t = -5.814; p < 0.001), while the difference in the first cycle between groups was not statistically significant. (t = -0.258; P = 0.803). This simulation-based study demonstrated that the UK ALS guidelines led to an increased duration of hands-off time during the second cycle. The hands-off time in the shockable rhythms was also higher during the second, third, and fourth cycles in the UK ALS protocol compared to the Australian ALS protocol. These points must be focused on in future revisions of the UK ALS guidelines. For better results, it is critical to limit hands-off time between chest compression cycles.

Feasibility of resuscitative transesophageal echocardiography at out-of-hospital emergency scenes of cardiac arrest

Guidelines recommend the use of ultrasound in cardiac arrest. Transthoracic echocardiography, has issues with image quality and by increasing hands-off times during resuscitation. We assessed the feasibility of transesophageal echocardiography (TEE), which does not have both problems, at out-of-hospital cardiac arrest (OHCA) emergency scenes. Included were 10 adults with non-traumatic OHCA in Vienna, Austria. An expert in emergency ultrasound was dispatched to the scenes in addition to the resuscitation team. Feasibility was defined as the ability to collect specific items of information by TEE within 10 min. Descriptive statistics were compiled and hands-off times were compared to a historical control group. TEE examinations were feasible in 9 of 10 cases and prompted changes in clinical management in 2 cases (cardiac tamponade: n = 1; right ventricular dilatation: n = 1). Their mean time requirement was 5.1 ± 1.7 (2.8–8.0) min, and image quality was invariably rated as excellent or good during both compressions and pauses. No TEE-related complications, or interferences with activities of advanced life support were observed. The hands-off times during resuscitation were comparable to a historical control group not involving ultrasound (P = 0.24). Given these feasibility results, we expect that TEE can be used routinely at OHCA emergency scenes.

Abstract 308: Comparison of Cardiopulmonary Resuscitation Performance Between Integrated CPR Device Performing Chest Compression and External Defibrillation versus LUCAS3 With Automated External Defibrillator: A Animal and Manikin-Based Pilot Study

Background: Early chest compression and defibrillation are important components for successful resuscitation. The use of mechanical CPR has increased after the outbreak of COVID-19, and this trend continued in the post-pandemic period. We developed an automatic CPR performing chest compression and external defibrillation simultaneously following current CPR algorithm. Methods: This study was designed as a study to compare the performance of CPR and AED between automatic CPR apparatus (A-CPR) and commercially proven mechanical CPR device (LUCAS3) plus AED (C-CPR) during CPR in swine cardiac arrest model and the study to evaluate feasibility of A-CPR in simulated cardiac arrest model. Results: There were no significant differences in hemodynamic variables between the groups. Time to ECG analysis [38.0 sec in A-CPR, 48.0 sec in C-CPR, p =0.010], time to initial shock advice plus subsequent chest compression [46.0 sec in A-CPR, 57.0 sec in C-CPR, p =0.017], time to first defibrillation [48.5 sec in A-CPR, 65.0 sec in C-CPR, p =0.004], charge to shock interval [3.0 sec in A-CPR, 8.0 sec in C-CPR, p =0.001], and hands-off time [11.0 sec in A-CPR, 22.5 sec in C-CPR, p =0.001] were significantly shorter in A-CPR group than C-CPR group. In the simulation study, the pure chest compression time [101 sec in A-CPR, 110 sec in C-CPR, p&lt; 0.001], hands-off time [75 sec in A-CPR, 94 sec in C-CPR, p&lt; 0.001], time from power-on to first chest compression [55 sec in A-CPR, 82 sec in C-CPR, p&lt; 0.001], time to first shock delivery [40 sec in A-CPR, 51 sec in C-CPR, p= 0.001] were significantly shorter in A-CPR group than C-CPR group, respectively. Chest compression fraction showed a significant higher in A-CPR than C-CPR [57% in A-CPR, 54% in C-CPR, p &lt;0.001]. Conclusions: The A-CPR device demonstrated significant time savings effect than conventional mechanical CPR device and automated external defibrillation device. In addition, A-CPR and C-CPR showed similar hemodynamic effects and resuscitation outcomes in a swine model of cardiac arrest

Abstract 221: Heart Rhythm Analysis During Chest Compressions in Case of Out-of-Hospital Cardiac Arrest: Are Confirmation Analysis a Safety Issue?

Purpose: During out-of-hospital cardiac arrest (OHCA), automated external defibrillators (AEDs) can analyze the patient's cardiac rhythm using a Shock Advisory System (SAS) that runs during chest compressions (CC). We aimed to evaluate the safety of a SAS that enables analysis during CC, referred to as Analyze Whilst Compressing (AWC). AWC classifies the cardiac rhythm as shockable (Sh) or non-shockable (NSh) in the presence of CC. If shockable, the rescuer backs off while the AED confirms the rhythm in the absence of CC with a confirmation analysis (CoA). We aimed to verify the safety of AWC when patients present NSh rhythm during CC. Method: In this retrospective study, we utilized data from the Paris Fire Brigade collected between 01/01/2021 and 31/01/2022. The inclusion criteria were adult OHCA patients with initial Ventricular Fibrillation analyzed by the AWC algorithm. We analyzed patients' safety by assessing false positive cases in the presence of chest compressions: ill-advised CoA compared to appropriate CoA within the first 10 minutes of intervention. The main outcome was the rate of patients presenting ill-advised CoA. Results: We analyzed 285 consecutive OHCA patients, corresponding to 2011 rhythm analyses ; 205 patients had at least 1 CoA, which led to a confirmation rate of 27.7% over 557 analyses; 175 patients had at least one appropriate CoA; 76 patients (26.6%) had at least one ill-advised CoA: 48 (16.8%) had one ill-advised CoA, 19 (6.7%) had two ill-advised CoA, six patients (2.1%) had three ill-advised CoA, two patients (0.7%) had four ill-advised CoA, and one (0.35%) had six ill-advised CoA. The global amount of ill-advised CoA was 118, which leads to an ill-advised confirmation rate of 5.9%. The rhythm distribution implied with ill-advised CoA was: 72 (61%) asystole, 45 (38%) other non-shockable, one (0.85%) transition from Sh to NSh. The hands-off time that each ill-advised CoA generated was 10 [8-18] (median [IQR]) seconds. Conclusion: AWC presents comparable results to other methods of analysis during chest compressions in detecting some non-shockable rhythms as false positives. In a majority of patients, CoA was appropriate. Only one patient (0.35%) had up to six ill-advised CoA, making his impact negligible over the cohort.

Efficacy of Cardiopulmonary Resuscitation Using Automatic Compression-Defibrillation Apparatus: An Animal Study and A Manikin-Based Simulation Study.

Chest compression and defibrillation are essential components of cardiac arrest treatment. Mechanical chest compression devices (MCCD) and automated external defibrillators (AED) are used separately in clinical practice. We developed an automated compression-defibrillation apparatus (ACDA) that performs mechanical chest compression and automated defibrillation. We investigated the performance of cardiopulmonary resuscitation (CPR) with automatic CPR (A-CPR) compared to that with MCCD and AED (conventional CPR: C-CPR). Pigs were randomized into A-CPR or C-CPR groups: The A-CPR group received CPR+ACDA, and the C-CPR group received CPR+MCCD+AED. Hemodynamic parameters, outcomes, and time variables were measured. During a simulation study, healthcare providers performed a basic life support scenario for manikins with an ACDA, MCCD, and AED, and time variables and chest compression parameters were measured. The animals showed no significant in hemodynamic effects, including aortic pressures, coronary perfusion pressure, carotid blood flow, and end-tidal CO2, and resuscitation outcomes between the two groups. In both animal and simulation studies, the time to defibrillation, time to chest compression, and hands-off time were significantly shorter in the A-CPR group than those in the C-CPR group. CPR using ACDA showed similar hemodynamic effects and resuscitation outcomes as CPR using AED and MCCD separately, with the advantages of a reduction in the time to compression, time to defibrillation, and hands-off time.

Automated external defibrillator delivery by a drone in a mountainous region to treat sudden cardiac arrest

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): ZOLL Introduction Out-of-hospital cardiac arrest (OHCA) poses a tough medical challenge with poor survival rates. Factors that may enable survival include resuscitation measures initiated by a bystander, early use of an automated external defibrillator (AED), and further performance of advanced life support. The latter will arrive on scene with an inevitable time-delay due to logistics challenges and potential AED unavailability, especially in rural areas. Here, drones might deliver an AED in order to increase the probability of survival. Methods Ten paramedics and nineteen medical laypersons were confronted with a person suffering from OHCA within a field test scenario in a mountainous region (Bodental, Carinthia, Austria) without detailed information. The scenario included a mock-call to the emergency response center responsible for the Austrian State Carinthia that dispatched a semi-autonomously flying drone towards the caller’s GPS coordinates. During the emergency call, participants should perform cardiopulmonary resuscitation (CPR) measures and were informed that a drone delivers a training-AED. Various timepoints (time to (tt) emergency call, tt start CPR, tt drone start, tt first shock, hands-off times) as well as CPR quality were subject of analysis. Results The paramedics realized the cardiac arrest after 21 ± 11 seconds, the emergency call was performed after 40 ±43 seconds, the drone started after 5:15 ± 2:11 minutes and dropped off the AED after 10:52 ± 2:06 minutes, and the first shock was delivered after 12:15 ± 2:03 minutes. 70 % performed adequate chest compressions and 50 % provided sufficient mouth-to-mouth ventilation. Hands-off times were 50 ± 22 seconds. Only 37 % of the medical laypersons reported to know the algorithms for basic life support while 32 % performed adequate chest compressions and 68 % performed adequate mouth-to-mouth ventilation. In this group, the cardiac arrest was realized after 51 ±40 seconds, the emergency call was performed after 53 ±43 seconds, the drone started after 6:15 ± 1:33 minutes and dropped off the AED after 10:54 ± 1:56 minutes, and the first shock was delivered after 14:04 ± 2:10 minutes. Hands-off times were 2:11 ± 0:39 minutes. Conclusion The delivery and usage of an AED via a semi-autonomously flying drone in a remote region is feasible and safe. The drone delivery of an AED in mountainous regions can lead to early application of shocks. CPR quality performed by medical laypersons is suboptimal and emphasises the need for regular trainings.

Deep Learning Strategy for Sliding ECG Analysis during Cardiopulmonary Resuscitation: Influence of the Hands-Off Time on Accuracy.

This study aims to present a novel deep learning algorithm for a sliding shock advisory decision during cardiopulmonary resuscitation (CPR) and its performance evaluation as a function of the cumulative hands-off time. We retrospectively used 13,570 CPR episodes from out-of-hospital cardiac arrest (OHCA) interventions reviewed in a period of interest from 30 s before to 10 s after regular analysis of automated external defibrillators (AEDs). Three convolutional neural networks (CNNs) with raw ECG input (duration of 5, 10, and 15 s) were applied for the shock advisory decision during CPR in 26 sequential analyses shifted by 1 s. The start and stop of chest compressions (CC) can occur at arbitrary times in sequential slides; therefore, the sliding hands-off time (sHOT) quantifies the cumulative CC-free portion of the analyzed ECG. An independent test with CPR episodes in 393 ventricular fibrillations (VF), 177 normal sinus rhythms (NSR), 1848 other non-shockable rhythms (ONR), and 3979 asystoles (ASYS) showed a substantial improvement of VF sensitivity when increasing the analysis duration from 5 s to 10 s. Specificity was not dependent on the ECG analysis duration. The 10 s CNN model presented the best performance: 92-94.4% (VF), 92.2-94% (ASYS), 96-97% (ONR), and 98.2-99.5% (NSR) for sliding decision times during CPR; 98-99% (VF), 98.2-99.8% (ASYS), 98.8-99.1 (ONR), and 100% (NSR) for sliding decision times after end of CPR. We identified the importance of sHOT as a reliable predictor of performance, accounting for the minimal sHOT interval of 2-3 s that provides a reliable rhythm detection satisfying the American Heart Association (AHA) standards for AED rhythm analysis. The presented technology for sliding shock advisory decision during CPR achieved substantial performance improvement in short hands-off periods (>2 s), such as insufflations or pre-shock pauses. The performance was competitive despite 1-2.8% point lower ASYS detection during CPR than the standard requirement (95%) for non-noisy ECG signals. The presented deep learning strategy is a basis for improved CPR practices involving both continuous CC and CC with insufflations, associated with minimal CC interruptions for reconfirmation of non-shockable rhythms (minimum hands-off time) and early treatment of VF (minimal pre-shock pauses).

Differences in Automated External Defibrillator Types in Out-of-Hospital Cardiac Arrest Treated by Police First Responders

Background: Police first responder systems also including automated external defibrillation (AED) has in the past shown considerable impact on favourable outcomes after out-of-hospital cardiac arrest (OHCA). While short hands-off times in chest compressions are known to be beneficial, various AED models use different algorithms, inducing longer or shorter durations of crucial timeframes along basic life support (BLS). Yet, data on details of these differences, and also of their potential impact on clinical outcomes are scarce. Methods: For this retrospective observational study, patients with OHCA of presumed cardiac origin and initially shockable rhythm treated by police first responders in Vienna, Austria, between 01/2013 and 12/2021 were included. Data from the Viennese Cardiac Arrest Registry and AED files were extracted, and exact timeframes were analyzed. Results: There were no significant differences in the 350 eligible cases in demographics, return of spontaneous circulation, 30-day survival, or favourable neurological outcome between the used AED types. However, the Philips HS1 and -FrX AEDs showed immediate rhythm analysis after electrode placement (0 [0-1] s) and almost no shock loading time (0 [0-1] s), as opposed to the LP CR Plus (3 [0-4] and 6 [6-6] s, respectively) and LP 1000 (3 [2-10] and 6 [5-7] s, respectively). On the other hand, the HS1 and -FrX had longer analysis times of 12 [12-16] and 12 [11-18] s than the LP CR Plus (5 [5-6] s) and LP 1000 (6 [5-8] s). The duration from when the AED was turned on until the first defibrillation were 45 [28-61] s (Philips FrX), 59 [28-81] s (LP 1000), 59 [50-97] s (HS1), and 69 [55-85] s (LP CR Plus). Conclusion: In a retrospective analysis of OHCA-cases treated by police first responders, we could not find significant differences in clinical patient outcomes concerning the respective used AED model. However, various differences in time durations (e.g., electrode placement to rhythm analysis, analysis duration, or AED turned on until first defibrillation) along the BLS algorithm were seen. This opens up the question of AED-adaptations and tailored training methods for professional first responders.

Automated external defibrillator delivery by drone in mountainous regions to support basic life support – A simulation study

BackgroundOut-of-hospital cardiac arrest (OHCA) is associated with poor survival rates. Factors that may enable survival include cardiopulmonary resuscitation (CPR) initiated by bystanders and early use of an automated external defibrillator (AED). This explorative simulation study was conceptualized to test the feasibility of a semi-autonomously operating drone that delivers an AED to a remote emergency location and its bystander-use. MethodsTen paramedics and nineteen laypersons were confronted with a manikin simulating an OHCA as single bystanders within a field test located in a mountainous region between Austria and Slovenia. The scenario included a mock-call to the local emergency response center that dispatched a drone towards the caller’s GPS coordinates and supported the ongoing CPR. The outcomes were the successful delivery of the AED, the time to the first shock, hands-off times, and the overall performance of the CPR. ResultsThe AED was delivered by drone and used in all 29 scenarios without serious adverse events. The flight time of the drone was in median 5:20 (range: 1:35–8:19) minutes. The paramedics delivered the first shock after a mean of 12:15 ± 2:03 min and hands-off times were 50 ± 22 s. The laypersons delivered the first shock after 14:04 ± 2:10 min and hands-off times were 2:11 ± 0:39 min. All participants felt confident in the handling of the delivered AED. ConclusionThe delivery and usage of an AED via a semi-autonomously flying drone in a remote region is feasible. This approach can lead to early administration of shocks.

Prioritizing direct heart procurement in organ donors after circulatory death does not jeopardize lung transplant outcomes.

Controlled donation after circulatory death (cDCD) has become a standard in liver, kidney, and lung transplantation (LTx). Based on recent innovations in exvivo heart preservation, heart transplant centers have started to accept cDCD heart allografts. Because the heart has very limited tolerance to warm ischemia, changes to the cDCD organ procurement procedures are needed. These changes entail delayed ventilation and prolonged warm ischemia for the lungs. Whether this negatively impacts lung allograft function is unclear. A retrospective analysis of cDCD lungs transplanted between 2012 and February 2022 at the Medical University of Vienna was performed. The heart+lung group consisted of cases in which the heart was procured by a cardiac team for subsequent normothermic exvivo perfusion. A control group (lung group) was formed by cases where only the lungs were explanted. In heart+lung group cases, the heart procurement team placed cannulas after circulatory death and a hands-off time, collected donor blood for exvivo perfusion, and performed rapid organ perfusion with Custodiol solution, after which the heart was explanted. Up to this point, the lung procurement team did not interfere. No concurrent lung ventilation or pulmonary artery perfusion was performed. After the cardiac procurement team left the table, ventilation was initiated, and lung perfusion was performed directly through both stumps of the pulmonary arteries using 2 large-bore Foley catheters. This study analyzed procedural explant times, postoperative outcomes, primary graft dysfunction (PGD), duration of mechanical ventilation, length of intensive care unit (ICU) stay, and early survival after LTx. A total of 56 cDCD lungs were transplanted during the study period. In 7 cases (12.5%), the heart was also procured (heart+lung group); in 49 cases (87.5%), only the lungs were explanted (lung group). Basic donor parameters were comparable in the 2 groups. The median times from circulatory arrest to lung perfusion (24minutes vs 13.5minutes; P=.002) and from skin incision to lung perfusion (14minutes vs 5minutes; P=.005) were significantly longer for the heart+lung procedures. However, this did not affect post-transplantation PGD grade at 0hours (P=.851), 24hours (P=.856), 48hours (P=.929), and 72hours (P=.874). At 72hours after transplantation, none of the lungs in the heart+lung group but 1 lung (2.2%) in lung group was in PGD 3. The median duration of mechanical ventilation (50hours vs 41hours; P=.801), length of ICU stay (8days vs 6days; P=.951), and total length of hospital stay (27days vs 25days; P=.814) were also comparable in the 2 groups. In-hospital mortality occurred in only 1 patient of the lung group (2.2%). Although prioritized cDCD heart explantation is associated with delayed ventilation and significantly longer warm ischemic time to the lungs, post-LTx outcomes within the first year are unchanged. Prioritizing heart perfusion and explantation in the setting of cDCD procurement can be considered acceptable.

Analysis and Improvement Plan of Chest Compression and Ventilation during Transport

This study aimed to compare the outcomes of manual and automated chest compressions during virtual reality (VR)-based ambulance transport and measure the ventilation and airway pressure provided by different types of portable positive pressure ventilation in the national fire academy. The chest compression depths were 53.78 mm and 49.01 mm for automated and manual chest compressions, respectively, showing that automated chest compression achieved the appropriate compression depth. The compression rates were 101.8 times per min and 122.6 times per min for automated and manual compressions, respectively; however, the manual compression rate was irregular, ranging from 54∼178 times per min. The amounts of ventilation delivered by the portable positive pressure ventilator were 427.01 ml, 302.87 ml and 455.67 ml for models 1, 2 and 3, respectively, showing that models 1 and 3 delivered the appropriate amounts of ventilation. Therefore, automated chest compression is effective regarding compression depth and rate, incomplete release and release rate, hands-off time and compression site during VR-based patient transport. Portable positive pressure ventilators are easy to apply and can be used during patient transport; however, the ventilation varies according to the type used.

New chest compression method in infant resuscitation: Cross thumb technique

BackgroundThe two-thumb encircling technique (2TT) is superior to the two-finger technique (2FT) in infant cardiopulmonary resuscitation (CPR), but there are difficulties in providing ventilation as soon as possible. We modified the 2TT to the cross-thumb technique (CTT) to maintain good CPR performance at the same position as 2FT. We aimed to compare the quality of chest compression and brief hands-off times in 2FT, 2TT, and CTT by a single rescuer using an infant CPR manikin model.MethodsThis study was designed as a prospective randomized controlled simulation-based study. We used the Resusci® Baby QCPR (Laerdal Medical, Stavanger, Norway) as a simulated 3-month-old infant. Ventilation was performed by the mouth-to-mouth technique using a chest compression-to-ventilation ratio of 30:2 as a single rescuer. Data on CPR quality, such as locations, rates, depth and release of chest compressions, hands-off times, and proper ventilation, were recorded using the Resusci® Baby QCPR and SkillReporter. Also, the chest compression fraction (CCF) was automatically calculated.ResultsThe depth of chest compression in 2FT, 2TT, and CTT were 40.0 mm (interquartile range [IQR] 39.0, 41.0), 42.0 mm (IQR 41.0, 43.0), and 42.0 mm (IQR 41.0, 43.0), respectively. The depth of chest compression in 2FT was shallower than that in the other two techniques (P<0.05). CCF in 2FT, 2TT, and CTT were 73.9% (IQR 72.2, 75.6), 71.2% (IQR 67.2, 72.2) and 71.3% (IQR 67.7, 74.1), respectively. CCF was higher in 2FT than in the other two techniques (P<0.05). Correct location in 2FT, 2TT, and CTT were 99.0% (IQR 86.0, 100.0), 100.0% (IQR 97.0, 100.0) and 100.0% (IQR 99.0, 100.0), respectively. Correct location in CTT and 2TT was higher than that in 2FT. Performing CTT, the subjective pain and fatigue score were lower than other two technique.ConclusionA new chest compression technique, CTT was better in chest compression depth compared with 2FT and may be helpful in maintaining correct chest compression location with less pain and fatigue in infant CPR.

Back Plate Marking of a Mechanical Chest Compression Device to Reduce the Duration of Chest Compression Interruptions.

ObjectiveTo compare the effectiveness of applying the back plate marking method vs the standard method, to a mechanical chest compression device, in regards to reducing the duration of chest compression interruptions during a simulated cardiac arrest.MethodsAn experimental study, one group pretest posttest design, conducted in a university-based hospital from November 2020 to October 2021. The study recruited 20 participants including emergency medical residents and paramedics. The participants were randomized into three-person teams and applied the device in both standard and back plate marking methods in sequential order. Teams were required to use a mechanical chest compression device in a manikin-based OHCA simulation to assess performance.ResultsThe median time pause for the deployment of the upper part of the device was significantly reduced (16 vs 21s, P < 0.01) in the back plate marking method, as was the total pause for device deployment (31.5 vs 38.75s, P = 0.03) and the proportion of total hands-off time attributable to device application interruption (43.08% vs 49.18%, P = 0.02). There was no difference between groups in the duration of all compression interruptions (70.5 vs 82.75s, P = 0.20) and compression fractions (77.85 vs 76.91%, P = 0.19).ConclusionThe back plate marking method was a significantly reduced time of the deployment of the upper part of the device and in regards to the overall pause for device deployment, but there was no difference in CPR quality between the two methods.

Improve Cardiac Emergency Preparedness by Building a Team-Based Cardiopulmonary Resuscitation Educational Plan.

ObjectiveTo design an innovative team-based cardiopulmonary resuscitation (CPR) educational plan for multiple bystanders and evaluate whether it was associated with better teamwork and higher quality of resuscitation.MethodsThe team-based CPR plan defined the process for a three-person team, emphasize task allocation, leadership, and closed-loop communication. Participants qualified for single-rescuer CPR skills were randomized into teams of 3. The teamwork performance and CPR operation skills were evaluated in one simulated cardiac arrest scenario before and after training on the team-based CPR plan. The primary outcomes were measured by the Team Emergency Assessment Measure (TEAM) scale and chest compression fraction (CCF).ResultsForty-three teams were included in the analysis. The team-based CPR plan significantly improved the team performance (global rating 6.7 ± 1.3 vs. 9.0 ± 0.7, corrected p < 0.001 after Bonferroni's correction). After implementing the team-based CPR plan, CCF increased [median 59 (IQR 48–69) vs. 64 (IQR 57–71%)%, corrected p = 0.002], while hands-off time decreased [median 233.2 (IQR 181.0–264.0) vs. 207 (IQR 174–222.9) s, corrected p = 0.02]. We found the average compression depth was significantly improved through the team-based CPR training [median 5.1 (IQR 4.7–5.6) vs. 5.3 (IQR 4.9–5.5) cm, p = 0.03] but no more significantly after applying the Bonferroni's correction (corrected p = 0.35). The compression depths were significantly improved by collaborating and exchanging the role of compression among the participants after the 6th min.ConclusionThe team-based CPR plan is feasible for improving bystanders teamwork performance and effective for improving resuscitation quality in prearrival care. We suggest a wide application of the team-based CPR plan in the educational program for better resuscitation performance in real rescue events.

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.