Continuous Cardiopulmonary Resuscitation Research Articles

Survival After Intra-Arrest Transport vs On-Scene Cardiopulmonary Resuscitation in Children

For pediatric out-of-hospital cardiac arrest (OHCA), emergency medical services (EMS) may elect to transport to the hospital during active cardiopulmonary resuscitation (CPR) (ie, intra-arrest transport) or to continue on-scene CPR for the entirety of the resuscitative effort. The comparative effectiveness of these strategies is unclear. To evaluate the association between intra-arrest transport compared with continued on-scene CPR and survival after pediatric OHCA, and to determine whether this association differs based on the timing of intra-arrest transport. This cohort study included pediatric patients aged younger than 18 years with EMS-treated OHCA between December 1, 2005 and June 30, 2015. Data were collected from the Resuscitation Outcomes Consortium Epidemiologic Registry, a prospective 10-site OHCA registry in the US and Canada. Data analysis was performed from May 2022 to February 2024. Intra-arrest transport, defined as an initiation of transport prior to the return of spontaneous circulation, and the interval between EMS arrival and intra-arrest transport. The primary outcome was survival to hospital discharge. Patients who underwent intra-arrest transport at any given minute after EMS arrival were compared with patients who were at risk of undergoing intra-arrest transport within the same minute using time-dependent propensity scores calculated from patient demographics, arrest characteristics, and EMS interventions. We examined subgroups based on age (<1 year vs ≥1 year). Of 2854 eligible pediatric patients (median [IQR] age, 1 [0-9] years); 1691 males [59.3%]) who experienced OHCA between December 2005 and June 2015, 1892 children (66.3%) were treated with intra-arrest transport and 962 children (33.7%) received continued on-scene CPR. The median (IQR) time between EMS arrival and intra-arrest transport was 15 (9-22) minutes. In the propensity score-matched cohort (3680 matched cases), there was no significant difference in survival to hospital discharge between the intra-arrest transport group and the continued on-scene CPR group (87 of 1840 patients [4.7%] vs 95 of 1840 patients [5.2%]; risk ratio [RR], 0.81 [95% CI, 0.59-1.10]). Survival to hospital discharge was not modified by the timing of intra-arrest transport (P value for the interaction between intra-arrest transport and time to matching = .10). Among patients aged younger than 1 year, intra-arrest transport was associated with lower survival to hospital discharge (RR, 0.52; 95% CI, 0.33-0.83) but there was no association for children aged 1 year or older (RR, 1.22; 95% CI, 0.77-1.93). In this cohort study of a North American OHCA registry, intra-arrest transport compared with continued on-scene CPR was not associated with survival to hospital discharge among children with OHCA. However, intra-arrest transport was associated with a lower likelihood of survival to hospital discharge among children aged younger than 1 year.

Impact of Personal Protective Equipment on Cardiopulmonary Resuscitation and Rescuer Safety

Background. High-quality cardiopulmonary resuscitation (CPR) is a key element in the rescue of cardiac arrest patients but is difficult to achieve in circumstances involving aerosol transmission, such as the COVID-19 pandemic. Methods. This prospective randomized crossover trial included 30 experienced health care providers to evaluate the impact of personal protective equipment (PPE) on CPR quality and rescuer safety. Participants were asked to perform continuous CPR for 5 minutes on a manikin with three types of PPE: level D-PPE, level C-PPE, and PAPR. The primary outcome was effective chest compression per minute. Secondary outcomes were the fit factor by PortaCount, vital signs and fatigue scores before and after CPR, and perceptions related to wearing PPE. Repeated-measures ANOVA was used, and a two-tailed test value of 0.05 was considered statistically significant. Results. The rates of effective chest compressions for 5 minutes with level D-PPE, level C-PPE, and PAPRs were 82.0 ± 0.2%, 78.4 ± 0.2%, and 78.0 ± 0.2%, respectively ( p = 0.584 ). The fit-factor test values of level C-PPE and PAPRs were 182.9 ± 39.9 vs. 198.9 ± 9.2 ( p &lt; 0.001 ). The differences in vital signs before and after CPR were not significantly different among the groups. In addition, the fatigue and total perception scores of wearing PPE were significantly higher for level C-PPE than PAPRs: 3.8 ± 1.6 vs. 3.0 ± 1.6 ( p &lt; 0.001 ) and 27.9 ± 5.4 vs. 26.0 ± 5.3 ( p &lt; 0.001 ), respectively. Conclusion. PAPRs are recommended when performing CPR in situations where aerosol transmission is suspected. When PAPRs are in short supply, individual fit-tested N95 masks are an alternative. This trial is registered with NCT04802109.

Meta-analysis of chest compression-only versus conventional cardiopulmonary resuscitation by bystanders for adult with out-of-hospital cardiac arrest.

According to the guidelines of cardiopulmonary resuscitation (CPR) conducted by bystanders, two methods of CPR are feasible: standard CPR (sCPR) with mouth-to-mouth ventilations and continuous chest compression-only CPR (CCC) without rescue breathing. The goal herein, was to evaluate the effect of sCPR (30:2) and CCC on resuscitation outcomes in patients with out-of-hospital cardiac arrest (OHCA) patients. This study was a systematic review and meta-analysis. Using standardized criteria, Pub- Med, Web of Science, Scopus, EMBASE and Cochrane Collaboration were searched for trials assessing the effect of sCPR vs. CCC on resuscitation outcomes after adult OHCA. Random-effects model meta-analysis was applied to calculate the mean deviation (MD), odds ratio (OR) and 95% confidence interval (CI). Overall, 3 randomized controlled trials and 12 non-randomized trials met the inclusion criteria. Survival to hospital discharge with sCPR was 10.2% compared to 9.3% in the CCC group (OR = 1.04; 95% CI: 0.93-1.16; p = 0.46). Survival to hospital discharge with good neurological outcome measured with the cerebral performance category (CPC 1 or 2) was 6.5% for sCPR vs. 5.8% for CCC (OR = 1.00; 95% CI: 0.84-1.20; p = 0.98). Prehospital return of spontaneous circulation (ROSC) in sCPR and CCC groups was 15.9% and 14.8%, respectively (OR = 1.13; 95% CI: 0.91-1.39; p = 0.26). Survival to hospital admission with ROSC occurred in 29.5% of the sCPR group compared to 28.4% in CCC group (OR = 1.20; 95% CI: 0.89-1.63; p = 0.24). This systematic review and meta-analysis concluded that there were no significant differences in the resuscitation outcomes between the use of standard cardiopulmonary resuscitation and chest compression only.

A comparative analysis of aerosol exposure and prevention strategies in bystander, pre-hospital, and inpatient cardiopulmonary resuscitation using simulation manikins

To evaluate aerosol exposure risk and prevention strategies during bystander, pre-hospital, and inpatient cardiopulmonary resuscitation (CPR). This study compared hands-only CPR, CPR with a surgical or N95 mask, and CPR with a non-rebreather mask at 15 L/min. 30:2 compression–ventilation ratio CPR was tested with face-mask ventilation (FMV), FMV with a high efficiency particulate air (HEPA) filter; supraglottic airway (SGA), SGA with a surgical mask, SGA with a HEPA filter, or SGA with both. Continuous CPR was tested with an endotracheal tube (ET), ET with a surgical mask, a HEPA filter, or both. Aerosol concentration at the head, trunk, and feet of the mannequin were measured to evaluate exposure to CPR personnel. Hands-only CPR with a surgical or N95 face mask coverings and ET tube ventilation CPR with filters showed the lowest aerosol exposure among all study groups, including CPR with NRM oxygenation, FMV, and SGA ventilation. NRM had a mask effect and reduced aerosol exposure at the head, trunk, and feet of the mannequin. FMV with filters during 30:2 CPR reduced aerosol exposure at the head and trunk, but increased at the feet of the mannequin. A tightly-sealed SGA when used with a HEPA filter, reduced aerosol exposure by 21.00–63.14% compared with a loose-fitting one. Hands-only CPR with a proper fit surgical or N95 face mask coverings is as safe as ET tube ventilation CPR with filters, compared with CPR with NRM, FMV, and SGA. FMV or tight-sealed SGA ventilation with filters prolonged the duration to achieve estimated infective dose of SARS-CoV-2 2.4–2.5 times longer than hands-on CPR only. However, a loose-fitting SGA is not protective at all to chest compressor or health workers standing at the foot side of the victim, so should be used with caution even when using with HEPA filters.

Effects of mechanical cardiopulmonary resuscitation during vertical spatial pre-hospital transport in patients with cardiac arrest: a historical cohort study

To analyze the effect of mechanical cardiopulmonary resuscitation (CPR) on patients with cardiac arrest with the vertical spatial pre-hospital emergency transport. A retrospective cohort study was conducted. The clinical data of 102 patients with out-of-hospital cardiac arrest (OHCA) who were transferred to the emergency medicine department of Huzhou Central Hospital from the Huzhou Emergency Center from July 2019 to June 2021 were collected. Among them, the patients who performed artificial chest compression during the pre-hospital transfer from July 2019 to June 2020 served as the control group, and the patients who performed artificial-mechanical chest compression (implemented artificial chest compression first, and implemented mechanical chest compression immediately after the mechanical chest compression device was ready) during pre-hospital transfer from July 2020 to June 2021 served as the observation group. The clinical data of patients of the two groups were collected, including basic data (gender, age, etc.), pre-hospital emergency process evaluation indicators [chest compression fraction (CCF), total CPR pause time, pre-hospital transfer time, vertical spatial transfer time], and in-hospital advanced resuscitation effect evaluation indicators [initial end-expiratory partial pressure of carbon dioxide (PETCO2), rate of restoration of spontaneous circulation (ROSC), time of ROSC]. Finally, a total of 84 patients were enrolled, including 46 patients in the control group and 38 in the observation group. There was no significant difference in gender, age, whether to accept bystander resuscitation or not, initial cardiac rhythm, time-consuming pre-hospital emergency response, floor location at the time of onset, estimated vertical height, and whether there was any vertical transfer elevator/escalator, etc. between the two groups. In the evaluation of the pre-hospital emergency process, the CCF during the pre-hospital emergency treatment of patients in the observation group was significantly higher than that in the control group [69.05% (67.35%, 71.73%) vs. 61.88% (58.18%, 65.04%), P < 0.01], the total pause time of CPR was significantly shorter than that in the control group [s: 266 (214, 307) vs. 332 (257, 374), P < 0.05]. However, there was no significant difference in the pre-hospital transfer time and vertical spatial transfer time between the observation group and the control group [pre-hospital transfer time (minutes): 14.50 (12.00, 16.75) vs. 14.00 (11.00, 16.00), vertical spatial transfer time (s): 32.15±17.43 vs. 27.96±18.67, both P > 0.05]. It indicated that mechanical CPR could improve the CPR quality in the process of pre-hospital first aid, and did not affect the transfer of patients by pre-hospital emergency medical personnel. In the evaluation of the in-hospital advanced resuscitation effect, the initial PETCO2 of the patients in the observation group was significantly higher than that of the patients in the control group [mmHg (1 mmHg ≈ 0.133 kPa): 15.00 (13.25, 16.00) vs. 12.00 (11.00, 13.00), P < 0.01], the time of ROSC was significantly shorter than that in the control group (minutes: 11.00±3.25 vs. 16.64±2.54, P < 0.01), and the rate of ROSC was slightly higher than that in the control group (31.58% vs. 23.91%, P > 0.05). It indicated that continuous mechanical compression during pre-hospital transfer helped to ensure continuous high-quality CPR. Mechanical chest compression can improve the quality of continuous CPR during the pre-hospital transfer of patients with OHCA, and improve the initial resuscitation outcome of patients.

First attempt success with continued versus paused chest compressions during cardiac arrest in the emergency department

AimTracheal intubation is associated with interruption in cardiopulmonary resuscitation (CPR). Current knowledge of tracheal intubation during active CPR focuses on the out-of-hospital environment. We aim to describe characteristics of tracheal intubation during active CPR in the emergency department (ED) and determine whether first attempt success was associated with CPR being continued vs paused. MeasurementsWe reviewed overhead video from adult ED patients receiving chest compressions at the start of the orotracheal intubation attempt. We recorded procedural detail including method of CPR, whether CPR was continued vs paused, and first attempt intubation success (primary outcome). We performed logistic regression to determine whether continuing CPR was associated with first attempt success. ResultsWe reviewed 169 instances of tracheal intubation, including 143 patients with continued CPR and 26 patients with paused CPR. Those with paused CPR were more likely to be receiving manual rather than mechanical chest compressions. Video laryngoscopy and bougie use were common. First attempt success was higher in the continued CPR group (87%, 95% CI 81% to 92%) than the interrupted CPR group (65%, 95% CI 44% to 83%, difference 22% [95% CI 3% to 41%]). The multivariable model demonstrated an adjusted odds ratio of 0.67 (95% CI 0.17 to 2.60) for first attempt intubation success when CPR was interrupted vs continued. ConclusionsIt was common to continue CPR during tracheal intubation, with success comparable to that achieved in patients without cardiac arrest. It is reasonable to attempt tracheal intubation without interrupting CPR, pausing only if necessary.

Abstract 301: RescueDoppler: Non-invasive Handsfree Carotid Doppler Ultrasound For Continuous Hemodynamic-guided Resuscitation

Introduction: Intermittent carotid pulse palpation (PP) is used to determine the return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR). PP requires interruption of CPR and has low accuracy. Therefore, we investigated if a novel continuous non-invasive hands-free Doppler ultrasound system (RescueDoppler; RD) could detect the presence of pulse/no pulse and ROSC in an experimental setting with ventricular fibrillation (VF) and severe hypotension. Methods: RD was attached to the neck with a self-adhesive bandage onto twelve pigs (mean weight of 30.4 kg). RD used multirange Doppler, with 32 depth ranges over 8 - 45 mm. The transducer dimension was 30 x 6 mm. The RD probe was placed over the carotid artery, while invasive blood pressure was recorded on the contralateral side. Two profound circulatory disturbances were initiated; 1) severe hypotension by vena cava inferior occlusion (VCO) using a 7 Fr Fogarty catheter with gradual balloon inflation and 2) VF by applying a 7.5 V direct current in the myocardium for 2 seconds using an implantable cardioverter-defibrillator placed in the right ventricle apex. The pigs were defibrillated back to ROSC. Mean velocity over one cardiac cycle (time-averaged velocity; TAV) was compared with mean arterial pressure (MAP). Results: RD detected flow in the carotid artery in all 41 VCO sequences (figure), including the lowest induced systolic blood pressure of 19 mmHg. The intraclass correlation coefficient was 0.76 between TAV and MAP. ROSC was equally identified by RD and invasive blood pressure in all 21 VF sequences where the pigs were defibrillated from VF to sinus rhythm (figure). Conclusion: The RD system was simple and required no ultrasound knowledge. RD detected ROSC and blood flow at extremely low invasive carotid blood pressures during VF and VCO. TAV correlated well with MAP. RD could become an essential non-invasive, hands-free tool for continuous hemodynamic-guided CPR.

Autoregulation of Cerebral Blood Flow During 3-h Continuous Cardiopulmonary Resuscitation at 27°C.

Introduction: Victims of accidental hypothermia in hypothermic cardiac arrest (HCA) may survive with favorable neurologic outcome if early and continuous prehospital cardiopulmonary resuscitation (CPR) is started and continued during evacuation and transport. The efficacy of cerebral autoregulation during hypothermic CPR is largely unknown and is aim of the present experiment. Methods: Anesthetized pigs (n = 8) were surface cooled to HCA at 27°C before 3 h continuous CPR. Central hemodynamics, cerebral O2 delivery (DO2) and uptake (VO2), cerebral blood flow (CBF), and cerebral perfusion pressure (CPP) were determined before cooling, at 32°C and at 27°C, then at 15 min after the start of CPR, and hourly thereafter. To estimate cerebral autoregulation, the static autoregulatory index (sARI), and the CBF/VO2 ratio were determined. Results: After the initial 15-min period of CPR at 27°C, cardiac output (CO) and mean arterial pressure (MAP) were reduced significantly when compared to corresponding values during spontaneous circulation at 27°C (−66.7% and −44.4%, respectively), and remained reduced during the subsequent 3-h period of CPR. During the first 2-h period of CPR at 27°C, blood flow in five different brain areas remained unchanged when compared to the level during spontaneous circulation at 27°C, but after 3 h of CPR blood flow in 2 of the 5 areas was significantly reduced. Cooling to 27°C reduced cerebral DO2 by 67.3% and VO2 by 84.4%. Cerebral VO2 was significantly reduced first after 3 h of CPR. Cerebral DO2 remained unaltered compared to corresponding levels measured during spontaneous circulation at 27°C. Cerebral autoregulation was preserved (sARI > 0.4), at least during the first 2 h of CPR. Interestingly, the CBF/VO2 ratio during spontaneous circulation at 27°C indicated the presence of an affluent cerebral DO2, whereas after CPR, the CBF/VO2 ratio returned to the level of spontaneous circulation at 38°C. Conclusion: Despite a reduced CO, continuous CPR for 3 h at 27°C provided sufficient cerebral DO2 to maintain aerobic metabolism and to preserve cerebral autoregulation during the first 2-h period of CPR. This new information supports early start and continued CPR in accidental hypothermia patients during rescue and transportation for in hospital rewarming.

Enhancing the accuracy of shock advisory algorithms in automated external defibrillators during ongoing cardiopulmonary resuscitation using a deep convolutional Encoder-Decoder filtering model

Survival from out-of-hospital cardiac arrests (OHCA) depends on an accurate defibrillatory shock decision during cardiopulmonary resuscitation (CPR). Since chest compressions induce severe motion artifact in the electrocardiogram (ECG), current automatic external defibrillators (AEDs) instruct the user not to perform CPR during the rhythm analysis period. However, performing continuous CPR is vital and dramatically increases the chance of survival. Hence, we demonstrate a novel application of a deep convolutional neural network encoder-decoder (CNNED) method to suppress CPR artifact in near real-time, using only ECG data. The encoder portion of the CNNED uses the magnitude and phase contents derived via time-varying spectral analysis to learn distinct features that are representative of both the ECG signal and CPR artifact. The decoder portion takes the results from the encoder and reconstructs what is perceived as the motion artifact-removed ECG data. These procedures are done via a multitude of training of the CNNED using many different arrhythmias contaminated with CPR. In this study, CPR-contaminated ECGs were generated by combining clean ECGs with 52 different CPR artifacts. ECG data from CUDB, VFDB, SDDB, and AFDB datasets which belong to the Physionet’s Physiobank archive were used to create the training set containing 14-second ECG segments. The performance of the proposed CNNED was evaluated on a separate test set comprised of 23,816 CPR-contaminated 14-second ECG segments from 458 subjects. The results were evaluated by three metrics: signal-to-noise ratio (SNR), correlation coefficient, and accuracy of Defibtech’s AED shock advisory algorithm (SAA). CNNED resulted in an increase of the mean SNR value from −3 dB to 7.5 dB and 7.1 dB for shockable and non-shockable rhythms, respectively. 80.85% of the filtered shockable and 74.13% of the filtered non-shockable ECG data were highly correlated (>0.7) with the artifact-free ECG; these values were only 13.30% and 12.71% for CPR-contaminated shockable and non-shockable, respectively, without our filtering approach. Comparing results of Defibtech’s AED SAA before and after applying CNNED on the CPR-contaminated ECG, the specificity improved from 96.21% to 99.14% for normal sinus rhythm, and from 88.5% to 96.45% for other non-shockable rhythms. The sensitivity of shockable detection also increased from 67.68% to 90.90% for ventricular fibrillation, and from 62.71% to 82.26% for ventricular tachycardia. These results indicate continuous and accurate AED rhythm analysis without stoppage of CPR, using only ECG data.

Impaired Pharmacokinetics of Amiodarone under Veno-Venous Extracorporeal Membrane Oxygenation: From Bench to Bedside.

Background: Adjusting drug therapy under veno-venous extracorporeal membrane oxygenation (VV ECMO) is challenging. Although impaired pharmacokinetics (PK) under VV ECMO have been reported for sedative drugs and antibiotics, data about amiodarone are lacking. We evaluated the pharmacokinetics of amiodarone under VV ECMO both in vitro and in vivo. Methods: In vitro: Amiodarone concentration decays were compared between closed-loop ECMO and control stirring containers over a 24 h period. In vivo: Potassium-induced cardiac arrest in 10 pigs with ARDS, assigned to either control or VV ECMO groups, was treated with 300 mg amiodarone injection under continuous cardiopulmonary resuscitation. Pharmacokinetic parameters Cmax, Tmax AUC and F were determined from both direct amiodarone plasma concentrations observation and non-linear mixed effects modeling estimation. Results: An in vitro study revealed a rapid and significant decrease in amiodarone concentrations in the closed-loop ECMO circuitry whereas it remained stable in control experiment. In vivo study revealed a 32% decrease in the AUC and a significant 42% drop of Cmax in the VV ECMO group as compared to controls. No difference in Tmax was observed. VV ECMO significantly modified both central distribution volume and amiodarone clearance. Monte Carlo simulations predicted that a 600 mg bolus of amiodarone under VV ECMO would achieve the amiodarone bioavailability observed in the control group. Conclusions: This is the first study to report decreased amiodarone bioavailability under VV ECMO. Higher doses of amiodarone should be considered for effective amiodarone exposure under VV ECMO.

Establishing a multicenter, preclinical consortium in resuscitation: A pilot experimental trial evaluating epinephrine in cardiac arrest

BackgroundLarge animal studies are an important step in the translation pathway, but single laboratory experiments do not replicate the variability in patient populations. Our objective was to demonstrate the feasibility of performing a multicenter, preclinical, randomized, double-blinded, placebo-controlled cardiac arrest trial. We evaluated the effect of epinephrine on coronary perfusion pressure (CPP) as previous single laboratory studies have reported mixed results. MethodsForty-five swine from 5 different laboratories (Ann Arbor, MI; Baltimore, MD; Los Angeles, CA; Pittsburgh, PA; Toronto, ON) using a standard treatment protocol. Ventricular fibrillation was induced and left untreated for 6 min before starting continuous cardiopulmonary resuscitation (CPR). After 2 min of CPR, 9 animals from each lab were randomized to 1 of 3 interventions given over 12 minutes: (1) Continuous IV epinephrine infusion (0.00375 mg/kg/min) with placebo IV normal saline (NS) boluses every 4 min, (2) Continuous placebo IV NS infusion with IV epinephrine boluses (0.015 mg/kg) every 4 min or (3) Placebo IV NS for both infusion and boluses. The primary outcome was mean CPP during the 12 mins of drug therapy. ResultsThere were no significant differences in mean CPP between the three groups: 14.4 ± 6.8 mmHg (epinephrine Infusion), 16.9 ± 5.9 mmHg (epinephrine bolus), and 14.4 ± 5.5 mmHg (placebo) (p = NS). Sensitivity analysis demonstrated inter-laboratory variability in the magnitude of the treatment effect (p = 0.004). ConclusionThis study demonstrated the feasibility of performing a multicenter, preclinical, randomized, double-blinded cardiac arrest trials. Standard dose epinephrine by bolus or continuous infusion did not increase coronary perfusion pressure during CPR when compared to placebo.

Accidental Hypothermia: 2021 Update.

Accidental hypothermia is an unintentional drop of core temperature below 35 °C. Annually, thousands die of primary hypothermia and an unknown number die of secondary hypothermia worldwide. Hypothermia can be expected in emergency patients in the prehospital phase. Injured and intoxicated patients cool quickly even in subtropical regions. Preventive measures are important to avoid hypothermia or cooling in ill or injured patients. Diagnosis and assessment of the risk of cardiac arrest are based on clinical signs and core temperature measurement when available. Hypothermic patients with risk factors for imminent cardiac arrest (temperature < 30 °C in young and healthy patients and <32 °C in elderly persons, or patients with multiple comorbidities), ventricular dysrhythmias, or systolic blood pressure < 90 mmHg) and hypothermic patients who are already in cardiac arrest, should be transferred directly to an extracorporeal life support (ECLS) centre. If a hypothermic patient arrests, continuous cardiopulmonary resuscitation (CPR) should be performed. In hypothermic patients, the chances of survival and good neurological outcome are higher than for normothermic patients for witnessed, unwitnessed and asystolic cardiac arrest. Mechanical CPR devices should be used for prolonged rescue, if available. In severely hypothermic patients in cardiac arrest, if continuous or mechanical CPR is not possible, intermittent CPR should be used. Rewarming can be accomplished by passive and active techniques. Most often, passive and active external techniques are used. Only in patients with refractory hypothermia or cardiac arrest are internal rewarming techniques required. ECLS rewarming should be performed with extracorporeal membrane oxygenation (ECMO). A post-resuscitation care bundle should complement treatment.

Abstract 12792: Enhancing the Accuracy of Cardiac Rhythm Analysis in Automated External Defibrillators During Ongoing Cardiopulmonary Resuscitation by Applying a Deep Encoder-Decoder Filtering Model

Survival from out-of-hospital cardiac arrests depends on an accurate defibrillatory shock decision during cardiopulmonary resuscitation (CPR). Since chest compressions induce severe motion artifact in the electrocardiogram (ECG), current automatic external defibrillators (AEDs) do not perform CPR during the rhythm analysis period. However, performing continuous CPR is vital and dramatically increases the chance of survival. Hence, we demonstrate a novel application of a deep convolutional neural network encoder-decoder (CNNED) method in suppressing CPR artifact in near real-time using only ECG data. The encoder portion of the CNNED uses the frequency and phase contents derived via time-varying spectral analysis to learn distinct features that are representative of both the ECG signal and CPR artifact. The decoder portion takes the results from the encoder and reconstructs what is perceived as the motion artifact removed ECG data. These procedures are done via multitude of training of CNNED using many different arrhythmia contaminated with CPR. In this study, CPR-contaminated ECGs were generated by combining clean ECG with CPR artifacts from 52 different performers. ECG data from CUDB, VFDB, and SDDB datasets which belong to the Physionet’s Physiobank archive were used to create the training set containing 89,984 14-second ECG segments. The performance of the proposed CNNED was evaluated on a separate test set comprising of 23,816 CPR-contaminated 14-second ECG segments from 458 subjects. The results were evaluated by two metrics: signal-to-noise ratio (SNR), and Defibtech’s AED rhythm analysis algorithm. CNNED resulted in the increase of the mean SNR value from -3 dB to 5.63 dB and 6.3 dB for shockable and non-shockable rhythms, respectively. Comparing Defibtech’s AED rhythm classifier before and after applying CNNED on the CPR-contaminated ECG, the specificity improved from 96.57% to 99.31% for normal sinus rhythm, and from 91.5% to 96.57% for other non-shockable rhythms. The sensitivity of shockable detection also increased from 67.68% to 87.76% for ventricular fibrillation, and from 62.71% to 81.27% for ventricular tachycardia. These results indicate continuous and accurate AED rhythm analysis without stoppage of CPR using only ECG data.

Design and application of rescue stretcher dedicated for cardiopulmonary resuscitation mechanical compression device

Continuous chest compressions during the transportation of patients with cardiac arrest have always been a difficult part in the field of pre-hospital emergency cardiopulmonary resuscitation (CPR). How to ensure continuous high-quality chest compressions is an important part of the patient's entire rescue process. At present, mechanical compression devices are commonly used to provide continuous high-quality chest compressions during the transportation. However, the installation process of the mechanical compression device involves posture changes of the patient, the placement of the device base, etc., and it is very likely to affect the continuous high-quality CPR treatment in the pre-hospital emergency process with limited human resources. Therefore, the First Affiliated Hospital of Huzhou University and Huzhou University jointly designed a rescue stretcher dedicated for CPR mechanical compression device, and has obtained the national utility model patent (ZL 2019 2 1005444.9). The main design feature of this stretcher is that the base of the compression device is combined with the stretcher, which eliminates the installation and fixation process of the base during the installation of the mechanical compression device, shortens the installation time. It has certain clinical applications value.

Rewarming With Closed Thoracic Lavage Following 3-h CPR at 27°C Failed to Reestablish a Perfusing Rhythm.

Introduction: Previously, we showed that the cardiopulmonary resuscitation (CPR) for hypothermic cardiac arrest (HCA) maintained cardiac output (CO) and mean arterial pressure (MAP) to the same reduced level during normothermia (38°C) vs. hypothermia (27°C). In addition, at 27°C, the CPR for 3-h provided global O2 delivery (DO2) to support aerobic metabolism. The present study investigated if rewarming with closed thoracic lavage induces a perfusing rhythm after 3-h continuous CPR at 27°C.Materials and Methods: Eight male pigs were anesthetized, and immersion-cooled. At 27°C, HCA was electrically induced, CPR was started and continued for a 3-h period. Thereafter, the animals were rewarmed by combining closed thoracic lavage and continued CPR. Organ blood flow was measured using microspheres.Results: After cooling with spontaneous circulation to 27°C, MAP and CO were initially reduced by 37 and 58% from baseline, respectively. By 15 min after the onset of CPR, MAP, and CO were further reduced by 58 and 77% from baseline, respectively, which remained unchanged throughout the rest of the 3-h period of CPR. During CPR at 27°C, DO2 and O2 extraction rate (VO2) fell to critically low levels, but the simultaneous small increase in lactate and a modest reduction in pH, indicated the presence of maintained aerobic metabolism. During rewarming with closed thoracic lavage, all animals displayed ventricular fibrillation, but only one animal could be electro-converted to restore a short-lived perfusing rhythm. Rewarming ended in circulatory collapse in all the animals at 38°C.Conclusion: The CPR for 3-h at 27°C managed to sustain lower levels of CO and MAP sufficient to support global DO2. Rewarming accidental hypothermia patients following prolonged CPR for HCA with closed thoracic lavage is not an alternative to rewarming by extra-corporeal life support as these patients are often in need of massive cardio-pulmonary support during as well as after rewarming.

Effects of rewarming with extracorporeal membrane oxygenation to restore oxygen transport and organ blood flow after hypothermic cardiac arrest in a porcine model

We recently documented that cardiopulmonary resuscitation (CPR) generates the same level of cardiac output (CO) and mean arterial pressure (MAP) during both normothermia (38 °C) and hypothermia (27 °C). Furthermore, continuous CPR at 27 °C provides O2 delivery (ḊO2) to support aerobic metabolism throughout a 3-h period. The aim of the present study was to investigate the effects of extracorporeal membrane oxygenation (ECMO) rewarming to restore ḊO2 and organ blood flow after prolonged hypothermic cardiac arrest. Eight male pigs were anesthetized and immersion cooled to 27 °C. After induction of hypothermic cardiac arrest, CPR was started and continued for a 3-h period. Thereafter, the animals were rewarmed with ECMO. Organ blood flow was measured using microspheres. After cooling with spontaneous circulation to 27 °C, MAP and CO were initially reduced to 66 and 44% of baseline, respectively. By 15 min after the onset of CPR, there was a further reduction in MAP and CO to 42 and 25% of baseline, respectively, which remained unchanged throughout the rest of 3-h CPR. During CPR, ḊO2 and O2 uptake (V̇O2) fell to critical low levels, but the simultaneous small increase in lactate and a modest reduction in pH, indicated the presence of maintained aerobic metabolism. Rewarming with ECMO restored MAP, CO, ḊO2, and blood flow to the heart and to parts of the brain, whereas flow to kidneys, stomach, liver and spleen remained significantly reduced. CPR for 3-h at 27 °C with sustained lower levels of CO and MAP maintained aerobic metabolism sufficient to support ḊO2. Rewarming with ECMO restores blood flow to the heart and brain, and creates a “shockable” cardiac rhythm. Thus, like continuous CPR, ECMO rewarming plays a crucial role in “the chain of survival” when resuscitating victims of hypothermic cardiac arrest.

Automated Chest Compression Allows Sufficient Resuscitation During Computed Tomography to Reveal the Cause of In-hospital Cardiac Arrest-A Case Report.

Computed tomography (CT) may be used to determine the reversible causes of in-hospital cardiac arrest (IHCA), while the automated chest compression devices (ACCDs) might be helpful to maintain sufficient circulation in x-ray environment during CT. We describe a case, where ACCD was used for continuous cardiopulmonary resuscitation during the CT procedure in an 82-year-old patient with IHCA of unknown cause. Artifact-free CT helped to identify the retroperitoneal hemorrhage as a cause of IHCA, which could not be identified using bedside diagnostics. This observation suggests ACCDs as a helpful adjunct for cardiopulmonary resuscitation in patients undergoing CT diagnostics of IHCA.

Shoulder strap fixation of LUCAS-2 to facilitate continuous CPR during non-supine (stair) stretcher transport of OHCAs patients

Early recognition and rapid initiation of high-quality cardiopulmonary resuscitation (CPR) are key to maximising chances of achieving successful return of spontaneous circulation in patients with out-of-hospital cardiac arrests (OHCAs), as well as improving patient outcomes both inside and outside hospital. Mechanical chest compression devices such as the LUCAS-2 have been developed to assist rescuers in providing consistent, high-quality compressions, even during transportation. However, providing uninterrupted and effective compressions with LUCAS-2 during transportation down stairwells and in tight spaces in a non-supine position is relatively impossible. In this study, we proposed adaptations to the LUCAS-2 to allow its use during transportation down stairwells and examined its effectiveness in providing high-quality CPR to simulated OHCA patients. 20 volunteer emergency medical technicians were randomised into 10 pairs, each undergoing 2 simulation runs per experimental arm (LUCAS-2 versus control) with a loaded Resusci Anne First Aid full body manikin weighing 60 kg. Quality of CPR compressions performed was measured using the CPRmeter placed on the sternum of the manikin. The respective times taken for each phase of the simulation protocol were recorded. Fisher’s exact tests were used to analyse categorical variables and median test to analyse continuous variables. The LUCAS-2 group required a longer time (~ 35 s) to prepare the patient prior to transport (p < 0.0001) and arrive at the ambulance (p < 0.0001) compared to the control group. The CPR quality in terms of depth and rate for the overall resuscitation period did not differ significantly between the LUCAS-2 group and control group, though there was a reduction in both parameters when evaluating the device’s automated compressions during transport. Nevertheless, the application of the LUCAS-2 device yielded a significantly higher chest compression fraction of 0.76 (p < 0.0001). Our novel adaptations to the LUCAS-2 device allow for uninterrupted compressions in patients being transported down stairwells, thus yielding better chest compression fractions for the overall resuscitation period. Whether potentially improved post-OHCA survival rates may be achieved requires confirmation in a real-world scenario study.

MLWAVE: A novel algorithm to classify primary versus secondary asphyxia-associated ventricular fibrillation

Introduction/HypothesisThe outcome of cardiopulmonary resuscitation (CPR) depends on timely recognition of the underlying cause of cardiac arrest. Ventricular fibrillation (VF) waveform analysis to differentiate primary VF from secondary asphyxia-associated VF may allow tailoring of therapies to improve cardiac arrest outcomes. Therefore, the primary goal of this investigation was to develop a novel technique utilizing wavelet synchrosqueezed transform (WSST) and decision-tree classifier that was specifically adapted to discriminate between these two incidents of VF. MethodsSecondary analytical investigation of electrocardiography (ECG) data obtained from swine models of either primary VF (n=18) or secondary asphyxia-associated VF (7min of asphyxia prior to VF induction; n=12). In the primary analysis, WSST technique was applied to the first 35s of the VF ECG signal to identify the most differentiating characteristics of the signal for use as features to develop a machine learning algorithm to classify the arrest as either primary VF vs. secondary asphyxia-associated VF. The performance of this new interactive Machine Learning algorithm with Wavelet Energy features of ECG (MLWAVE) was assessed using both classification accuracy and area under the receiver operating characteristic curve (AUCROC). To evaluate the validity of the new technique, the amplitude spectrum area (AMSA)-based technique, a well-established defibrillation classification method, was also applied to the same ECG signals. The classification accuracy and AUCROC were then compared between the two techniques. ResultsFor the primary analysis evaluating the first 35s of the VF waveform, the MLWAVE technique classified the type of VF with high accuracy (28/28 [100%], AUCROC: 1.00). The MLWAVE technique performed better than the AMSA technique across all comparisons, but given the small sample sizes, differences were not statistically significant (accuracy: 100% vs. 85.7%; p=0.24; AUCROC: 1.00 vs. 0.82; p=0.24). ConclusionThis analytical investigation illustrates the advantages of the MLWAVE signal processing method which was associated with 100% accuracy in classifying the type of VF waveform: primary vs. asphyxia-associated. Such classification could lead to personalized tailoring of resuscitation (e.g., immediate defibrillation vs. continued CPR and treatment of reversible cardiac arrest causes before defibrillation) to improve outcomes for cardiac arrest.

Abstract 131: Chest Molding in Extended Cardiopulmonary Resuscitation

Introduction: Cardiopulmonary resuscitation (CPR) is a forceful procedure that may change characteristics of the subject. Little clinical data has been published relating applied forces and depth responses, particularly in increasingly prevalent extended sessions of CPR. We analyzed synchronous force and depth records to investigate how chests mold during the course of extended CPR. Hypothesis: Chest molding, characterized as decrease in stiffness from its initial value, will increase as CPR proceeds. Methods: Force and acceleration signals were extracted from CPR monitors used in adult cases of continuous compression CPR in out-of-hospital resuscitations attended by a single EMS agency (TVFR, Tigard, Oregon) during 2013 through 2017. We computed depth and velocity from acceleration, and identified chest compressions automatically where downward velocity crossed 25mm/s and force subsequently exceeded 5 kg-f. Series were defined as sequences without pauses exceeding 2 minutes. We analyzed initial series lasting at least 10 minutes. We calculated stiffness as force/depth at peak compression velocity. We calculated molding in 5 minute blocks of CPR as 100*(1- stiffnessblock/stiffnessminute 1), using medians as stiffness was not normally distributed. Dependence of molding on CPR duration was analyzed with Kruskal-Wallis ANOVA. Results and Conclusions: Of 616 available cases, 478 had initial CPR series &gt;= 10 minutes duration, including 997,254 compressions. Initial CPR series duration were &gt;= 30 minutes in 152 cases, and &gt;= 40 minutes in 48 cases. The longest initial series was 61 minutes. Chest molding increased steadily through the first 25 minutes of CPR, and plateaued thereafter (p &lt; 0.001). Median molding at &gt;= 25 minutes was 20%. The implications of declining stiffness warrant further investigation.