Prediction of blood pressure using chest compression waveform during cardiopulmonary resuscitation.

OBJECTIVES: This study aimed to predict blood pressure during CPR using chest compression waveform information obtained from a CPR feedback device. METHODS: Quantitative data including chest compression waveforms from a CPR feedback device and the blood pressure measured by arterial cannulation in patients with cardiac arrest during CPR were used. Forty-one features to predict blood pressure were selected from chest compression waveform and demographic characteristics with neighborhood component analysis algorithm. Optimized Gaussian process regression was used as a machine learning algorithm. RESULTS: A total of 14,619 datasets from 19 patients with cardiac arrest (mean age: 66 ± 13 years, 14 men) were used in the analysis. The model could predict blood pressure with high precision and low bias for almost the whole range of systolic (SBP), diastolic (DBP), and mean arterial blood pressure (MAP). The correlation coefficients (r) between the predicted and actual values were 0.954 (95% confidence interval: 0.951-0.957, p < 0.001) for SBP, 0.926 (95% confidence interval: 0.921-0.931, p < 0.001) for DBP, and 0.958 (95% confidence interval: 0.955-0.961, p < 0.001) for MBP, which all indicated a very good agreement. CONCLUSIONS: Blood pressure generated by chest compressions can be predicted with high accuracy by a machine learning method using chest compression waveform information obtained from a CPR feedback device and the patient's demographic characteristics. Real-time provision of the predicted blood pressure can be used to monitor the quality and efficacy of CPR.

Vitamin D deficiency as a risk factor for sudden cardiac arrest: A multicenter case-control study.

BACKGROUND AND AIMS: Vitamin D is known to influence the risk of cardiovascular disease, which is a recognized risk factor for sudden cardiac arrest (SCA). However, the relationship between vitamin D and SCA is not well understood. Therefore, this study aims to investigate the association between vitamin D and SCA in out-of-hospital cardiac arrest (OHCA) patients compared to healthy controls. METHODS AND RESULTS: Using the Phase II Cardiac Arrest Pursuit Trial with Unique Registration and Epidemiologic Surveillance (CAPTURES II) registry, a 1:1 propensity score-matched case-control study was conducted between 2017 and 2020. Serum 25-hydroxyvitamin D (vitamin D) levels in patients with OHCA (454 cases) and healthy controls (454 cases) were compared after matching for age, sex, cardiovascular risk factors, and lifestyle behaviors. The mean vitamin D levels were 14.5 ± 7.6 and 21.3 ± 8.3 ng/mL among SCA cases and controls, respectively. Logistic regression analysis was used adjusting for cardiovascular risk factors, lifestyle behaviors, corrected serum calcium levels, and estimated glomerular filtration rate (eGRF). The adjusted odds ratio (aOR) for vitamin D was 0.89 (95% confidence interval [CI] 0.87-0.91). The dose-response relationship demonstrated that vitamin D deficiency was associated with SCA incidence (severe deficiency, aOR 10.87, 95% CI 4.82-24.54; moderate deficiency, aOR 2.24, 95% CI 1.20-4.20). CONCLUSION: Vitamin D deficiency was independently and strongly associated with an increased risk of SCA, irrespective of cardiovascular and lifestyle factors, corrected calcium levels, and eGFR.

Hemodynamic Effect of Repeated Epinephrine Doses Decreases With Cardiopulmonary Resuscitation Cycle Progression.

BACKGROUND: Epinephrine is administered to increase coronary perfusion pressure during advanced life support and promote short-term survival. Recent cardiopulmonary resuscitation (CPR) guidelines recommend an epinephrine dosing interval of 3 to 5 minutes during resuscitation; however, scientific evidence supporting this recommendation is lacking. Therefore, we aimed to investigate the hemodynamic effects of repeated epinephrine doses during CPR by monitoring augmented blood pressure after its administration in a swine model of cardiac arrest. METHODS AND RESULTS: A secondary analysis of data from a published study was performed using a swine cardiac arrest model. The epinephrine dose was fixed at 1 mg, and the first dose of epinephrine was administered after no-flow and low-flow times of 2 minutes and 8 minutes, respectively, and subsequently administered every 4 minutes. Four cycles of dosing intervals were defined because a previous study was terminated 26 minutes after the induction of ventricular fibrillation. Augmented blood pressures and corresponding timelines were determined. Augmented blood pressure trends following cycles and the epinephrine effect duration were also monitored. Among the 140 CPR cycles, the augmented blood pressure after epinephrine administration was the highest during the first cycle of CPR and decreased gradually with further cycle repetitions. The epinephrine effect duration did not differ between repeated cycles. The maximum blood pressure was achieved 78 to 97 seconds after epinephrine administration. CONCLUSIONS: Hemodynamic augmentation with repeated epinephrine administration during CPR decreased with cycle progression. Further studies are required to develop an epinephrine administration strategy to maintain its hemodynamic effects during prolonged resuscitation.

End-tidal carbon dioxide after sodium bicarbonate infusion during mechanical ventilation or ongoing cardiopulmonary resuscitation.

PURPOSE: End-tidal CO2 is used to monitor the ventilation status or hemodynamic efficacy during mechanical ventilation or cardiopulmonary resuscitation (CPR), and it may be affected by various factors including sodium bicarbonate administration. This study investigated changes in end-tidal CO2 after sodium bicarbonate administration. MATERIALS AND METHODS: This single-center, prospective observational study included adult patients who received sodium bicarbonate during mechanical ventilation or CPR. End-tidal CO2 elevation was defined as an increase of ≥20% from the baseline end-tidal CO2 value. The time to initial increase (lag time, Tlag), time to peak (Tpeak), and duration of the end-tidal CO2 rise (Tduration) were compared between the patients with spontaneous circulation (SC group) and those with ongoing resuscitation (CPR group). RESULTS: Thirty-three patients, (SC group, n = 25; CPR group, n = 8), were included. Compared with the baseline value, the median values of peak end-tidal CO2 after sodium bicarbonate injection increased by 100% (from 21 to 41 mmHg) in all patients, 89.5% (from 21 to 39 mmHg) in the SC group, and 160.2% (from 15 to 41 mmHg) in the CPR group. The median Tlag was 17 s (IQR: 12-21) and the median Tpeak was 35 s (IQR: 27-52). The median Tduration was 420 s (IQR: 90-639). The median Tlag, Tpeak, and Tduration were not significantly different between the groups. Tduration was associated with the amount of sodium bicarbonate for SC group (correlation coefficient: 0.531, p = 0.006). CONCLUSION: The administration of sodium bicarbonate may lead to a substantial increase in end-tidal CO2 for several minutes in patients with spontaneous circulation and in patients with ongoing CPR. After intravenous administration of sodium bicarbonate, the use of end-tidal CO2 pressure as a physiological indicator may be limited.

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

BACKGROUND: 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). METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Weakly coordinated Li ion in single-ion-conductor-based composite enabling low electrolyte content Li-metal batteries.

The pulverization of lithium metal electrodes during cycling recently has been suppressed through various techniques, but the issue of irreversible consumption of the electrolyte remains a critical challenge, hindering the progress of energy-dense lithium metal batteries. Here, we design a single-ion-conductor-based composite layer on the lithium metal electrode, which significantly reduces the liquid electrolyte loss via adjusting the solvation environment of moving Li+ in the layer. A Li||Ni0.5Mn0.3Co0.2O2 pouch cell with a thin lithium metal (N/P of 2.15), high loading cathode (21.5 mg cm-2), and carbonate electrolyte achieves 400 cycles at the electrolyte to capacity ratio of 2.15 g Ah-1 (2.44 g Ah-1 including mass of composite layer) or 100 cycles at 1.28 g Ah-1 (1.57 g Ah-1 including mass of composite layer) under a stack pressure of 280 kPa (0.2 C charge with a constant voltage charge at 4.3 V to 0.05 C and 1.0 C discharge within a voltage window of 4.3 V to 3.0 V). The rational design of the single-ion-conductor-based composite layer demonstrated in this work provides a way forward for constructing energy-dense rechargeable lithium metal batteries with minimal electrolyte content.

Development of an automatic device performing chest compression and external defibrillation: An animal-based pilot study.

BACKGROUND: Automatic chest compression devices (ACCDs) can promote high-quality cardiopulmonary resuscitation (CPR) and are widely used worldwide. Early application of automated external defibrillators (AEDs) along with high-quality CPR is crucial for favorable outcomes in patients with cardiac arrest. Here, we developed an automated CPR (A-CPR) apparatus that combines ACCD and AED and evaluated its performance in a pilot animal-based study. METHODS: Eleven pigs (n = 5, A-CPR group; n = 6, ACCD CPR and AED [conventional CPR (C-CPR)] group) were enrolled in this study. After 2 min observation without any treatment following ventricular fibrillation induction, CPR with a 30:2 compression/ventilation ratio was performed for 6 min, mimicking basic life support (BLS). A-CPR or C-CPR was applied immediately after BLS, and resuscitation including chest compression and defibrillation, was performed following a voice prompt from the A-CPR device or AED. Hemodynamic parameters, including aortic pressure, right atrial pressure, coronary perfusion pressure, carotid blood flow, and end-tidal carbon dioxide, were monitored during resuscitation. Time variables, including time to start rhythm analysis, time to charge, time to defibrillate, and time to subsequent chest compression, were also measured. RESULTS: There were no differences in baseline characteristics, except for arterial carbon dioxide pressure (39 in A-CPR vs. 33 in C-CPR, p = 0.034), between the two groups. There were no differences in hemodynamic parameters between the groups. However, time to charge (28.9 ± 5.6 s, A-CPR group; 47.2 ± 12.4 s, C-CPR group), time to defibrillate (29.1 ± 7.2 s, A-CPR group; 50.5 ± 12.3 s, C-CPR group), and time to subsequent chest compression (32.4 ± 6.3 s, A-CPR group; 56.3 ± 10.7 s, C-CPR group) were shorter in the A-CPR group than in the C-CPR group (p = 0.015, 0.034 and 0.02 respectively). CONCLUSIONS: A-CPR can provide effective chest compressions and defibrillation, thereby shortening the time required for defibrillation.

Intra-arrest transesophageal echocardiography during cardiopulmonary resuscitation.

Determining the cause of cardiac arrest (CA) and the heart status during CA is crucial for its treatment. Transesophageal echocardiography (TEE) is an imaging method that facilitates close observation of the heart without interfering with cardiopulmonary resuscitation (CPR). Intra-arrest TEE is a point-of-care ultrasound technique that is used during CPR. Intra-arrest TEE is performed to diagnose the cause of CA, determine the presence of cardiac contraction, evaluate the quality of CPR, assist with catheter insertion, and explore the mechanism of blood flow during CPR. The common causes of CA diagnosed using intra-arrest TEE include cardiac tamponade, aortic dissection, pulmonary embolism, and intracardiac thrombus, which can be observed on a few simple image planes at the mid-esophageal and upper esophageal positions. To operate an intra-arrest TEE program, it is necessary to secure a physician who is capable of performing TEE, provide appropriate training, establish implementation protocols, and prepare a plan in collaboration with the CPR team.

Diet-related complications according to the timing of enteral nutrition support in patients who recovered from out-of-hospital cardiac arrest: a propensity score matched analysis.

BACKGROUND: A proper nutritional plan for resuscitated patients is important in intensive care; however, specific nutritional guidelines have not yet been established. This study aimed to determine the incidence of diet-related complications that were affected by the timing of enteral nutrition in resuscitated patients after cardiac arrest. METHODS: This retrospective and 1:1 propensity score matching study involved patients who recovered after nontraumatic, out-of-hospital cardiac arrest at a tertiary hospital. Patients were divided into an early nutrition support (ENS) group and a delayed nutrition support (DNS) group according to the nutritional support time within 48 hours after admission. The incidence of major clinical complications was compared between the groups. RESULTS: A total of 46 patients (ENS: 23, DNS: 23) were enrolled in the study. There were no differences in body mass index, comorbidity, and time of cardiopulmonary resuscitation between the two groups. There were 9 patients (ENS: 4, DNS: 5) with aspiration pneumonia; 4 patients (ENS: 2, DNS: 2) with regurgitation; 1 patient (ENS: 0, DNS: 1) with ileus; 21 patients (ENS: 10, DNS: 11) with fever; 13 patients (ENS: 8, DNS: 5) with hypoglycemia; and 20 patients (ENS: 11, DNS: 9) with hyperglycemia. The relative risk of each complication during post-resuscitation care was no different between groups. CONCLUSIONS: There was a similar incidence of diet-related complications during post cardiac arrest care according to the timing of enteral nutrition.

Right-to-Left Shunts Occur During Cardiopulmonary Resuscitation: Echocardiographic Observations.

OBJECTIVES: A significant proportion of the population has a patent foramen ovale (PFO). The intracardiac pressure during cardiopulmonary resuscitation (CPR) may differ from that of normal circulation, which may result in a right-to-left shunt in the presence of a PFO. In this study, transesophageal echocardiography (TEE) was conducted to evaluate whether CPR carried out in patients after cardiac arrest causes right-to-left shunt. DESIGN: A retrospective observational study. SETTING: One academic medical center from January 2017 to April 2020. PATIENTS: Patients older than 20 years who suffered from nontraumatic out-of-hospital cardiac arrest (OHCA) and underwent intra-arrest TEE. MEASUREMENT AND MAIN RESULTS: Patients who had microbubbles resulting from fluid injection in the right atrium, as indicated on TEE imaging, were included in the analysis. The presence of right-to-left shunt was defined as the appearance of microbubbles in the systemic circulation, including the left atrium, left ventricle, or aorta. A total of 97 patients were included in the final analysis. A right-to-left shunt was observed in 21 patients (21.6%), and no shunt was found in 76 patients (78.4%). The degree of the right-to-left shunt, determined by the number of microbubbles, was mild in 11 patients (52.4%), moderate in eight (38.0%), and severe in two (9.6%). Multivariate analysis showed that no factors were associated with the presence of right-to-left shunt during CPR. CONCLUSIONS: Right-to-left shunts can be appreciated during CPR in patients who experience OHCA. Further studies are needed to verify its clinical significance.

Healthy lifestyle factors, cardiovascular comorbidities, and the risk of sudden cardiac arrest: A case-control study in Korea.

AIMS: We investigated the impact of healthy lifestyle factors and cardiovascular comorbidities for sudden cardiac arrest. METHODS: A case-control study, including patients with sudden cardiac arrest aged 20-79 years and community-based 1:2 matched controls, was conducted from September 2017 to December 2020. All participants completed a structured questionnaire. Using multivariable logistic regression, we assessed cardiovascular comorbidities (diabetes, hypertension, dyslipidaemia, myocardial infarction, congestive heart failure, arrhythmia, and stroke) and healthy lifestyle factors (low red meat consumption, low fish consumption, high fruit consumption, high vegetable consumption, current non-smoking, regular exercise, and adequate sleep duration) as sudden cardiac arrest risk factors. RESULTS: Among 3027 eligible cases, informed consent was obtained from 949 (31.3%) cases. A total of 1731 controls were enrolled. Cardiovascular comorbidities, except dyslipidaemia, were associated with an increased risk of sudden cardiac arrest, whereas all healthy lifestyle factors were associated with a decreased risk. Relative to patients in the 0-2 healthy lifestyle factors group, the adjusted odds ratio (95% confidence interval) for sudden cardiac arrest was 0.25 (0.16-0.40) in patients with 3 healthy lifestyle factors, 0.08 (0.05-0.13) in patients with 4 healthy lifestyle factors, and 0.04 (0.03-0.06) in patients with over 5 healthy lifestyle factors. When the number of healthy lifestyle factors was analysed as a continuous variable, each additional factor was associated with a significant decrease in the likelihood of sudden cardiac arrest (adjusted odds ratio [95% confidence interval]: 0.41 [0.36-0.46]). CONCLUSION: The increased risk of sudden cardiac arrest by cardiovascular comorbidities could be significantly reduced with healthy lifestyle factors.

An electron-deficient carbon current collector for anode-free Li-metal batteries.

The long-term cycling of anode-free Li-metal cells (i.e., cells where the negative electrode is in situ formed by electrodeposition on an electronically conductive matrix of lithium sourced from the positive electrode) using a liquid electrolyte is affected by the formation of an inhomogeneous solid electrolyte interphase (SEI) on the current collector and irregular Li deposition. To circumvent these issues, we report an atomically defective carbon current collector where multivacancy defects induce homogeneous SEI formation on the current collector and uniform Li nucleation and growth to obtain a dense Li morphology. Via simulations and experimental measurements and analyses, we demonstrate the beneficial effect of electron deficiency on the Li hosting behavior of the carbon current collector. Furthermore, we report the results of testing anode-free coin cells comprising a multivacancy defective carbon current collector, a LixNi0.8Co0.1Mn0.1-based cathode and a nonaqueous Li-containing electrolyte solution. These cells retain 90% of their initial capacity for over 50 cycles under lean electrolyte conditions.

Diagnosis of aortic dissection by transesophageal echocardiography during cardiopulmonary resuscitation.

OBJECTIVES: Early identification of the causes of cardiac arrest is helpful in determining the resuscitation measures during cardiopulmonary resuscitation (CPR). We aimed to evaluate the feasibility of transesophageal echocardiography (TEE) during CPR in diagnosing aortic dissection and the influence of aortic dissection on resuscitation outcome in adult patients with prolonged non-traumatic cardiac arrest. METHODS: Adult patients aged >20 years with non-traumatic cardiac arrest who underwent prolonged CPR (>10 min) and TEE examination during CPR were enrolled. The enrolled patients were grouped according to the presence of aortic dissection on TEE: the aortic dissection (AD) group and the non-AD group. Variables related to cardiac arrest event, CPR, and resuscitation outcome were compared between the two groups. RESULTS: Forty-five patients (median age, 71 years; 26 men) were enrolled. Ten (22.2%) and 35 (77.8%) patients were included in the AD and non-AD groups, respectively. No patients in the AD group survived. Aortic dissection on TEE was inversely related to the rate of return of spontaneous circulation on multivariate analysis (odds ratio, 0.019; 95% confidence interval, 0.001-0.750; p = .035). CONCLUSION: TEE is a useful tool for diagnosing aortic dissection as a cause of cardiac arrest during CPR. Aortic dissection is associated with poor resuscitation outcomes.

Delayed Splenic Rupture: A Rare Complication of Snakebites.

Bites by venomous snakes can cause fatal systemic and coagulation disorders. Rare complications, such as compartment syndrome and hemoperitoneum, may also require surgical intervention. Here, we describe our experience with an unusual case of snakebite-induced delayed splenic rupture. A 54-y-old male with no specific medical history visited a local hospital for a bite by an unidentified snake. He had been bitten on the left thumb and was administered antivenom. He was discharged from the local hospital after 3 d when his symptoms had improved. However, he revisited our emergency medical center 2 d later, reporting dizziness with diaphoresis. Focused abdominal ultrasonography and computed tomography revealed large amounts of intraperitoneal fluid collection and hemoperitoneum with splenic rupture, respectively. The patient underwent immediate blood transfusion and received antivenom treatment in our emergency department and, subsequently, emergency splenectomy. Histopathologic findings at the time of surgery revealed multifocal lacerations on the external surface of the spleen, with fresh hemorrhage. He recovered 7 d after surgery without any complication.

Intra-arrest transoesophageal echocardiographic findings and resuscitation outcomes.

BACKGROUND/AIM: The relationship between echocardiographic findings of intra-arrest TEE and resuscitation outcomes was not clearly identified. We assessed echocardiographic findings observed in intra-arrest TEE and its relationship with resuscitation outcomes. METHODS: This retrospective observational study analysed adult patients with non-traumatic out-of-hospital cardiac arrest who underwent TEE during cardiopulmonary resuscitation in the emergency department. Patients were grouped according to the presence of specific TEE findings with cardiac arrest. Resuscitation outcomes were compared between groups. RESULTS: The study enrolled 158 patients (108 males, median age: 72.5 years), 40 (25.3%) patients (TEE positive group) had specific TEE findings including possible causes of cardiac arrest in 31 (19.6%) and the sequela of cardiac arrest in 9 (5.7%) while 118 (74.7%) patients (TEE negative group) had no specific TEE findings. In the TEE positive group, TEE identified possible causes of cardiac arrest including aortic dissection in 19 (47.5%), pulmonary embolism in 8 (20.0%), cardiac tamponade in 4 (10.0%), and the sequela of cardiac arrest including intracardiac thrombi in 9 (22.5%) patients. No patients in the TEE positive group and 7 patients (5.9%) in the TEE negative group survived to hospital discharge. Return of spontaneous circulation rates were 27.5% and 39.8% in the TEE positive and TEE negative groups, respectively (p = 0.16). CONCLUSION: Intra-arrest TEE identifies specific findings related to causes of cardiac arrest. Presence of specific findings is associated with poor resuscitation outcomes.

Shorter defibrillation interval promotes successful defibrillation and resuscitation outcomes.

AIM: Current cardiopulmonary resuscitation guidelines recommend performing defibrillation every 2 min during resuscitation. This study aimed to compare the rate of successful defibrillation using 1- and 2-min defibrillation intervals. METHODS: Twenty-six pigs were randomly assigned to 1- or 2-min interval groups. After inducing ventricular fibrillation (VF), we observed pigs for 2 min. Thereafter, basic life support was initiated with a 30:2 compression-to-ventilation ratio for 8 min. Defibrillation was performed with an energy of 2 J/kg at 10 min after VF and was repeated every 1 or 2 min according to randomization. Advanced cardiac life support, including continuous chest compression with ventilation every 6 s and intravenous injection of 1 mg epinephrine every 3 min, was performed until the return of spontaneous circulation (ROSC) or until 20 min after VF induction. Haemodynamic parameters and baseline arterial blood gas profiles were compared between groups. ROSC, 24 -h survival, and the neurologic deficit score (NDS) were evaluated at 24 h. RESULTS: Haemodynamic parameters during resuscitation and baseline arterial blood gas profiles did not differ between groups. ROSC was more frequently observed in the 1-min interval group (p = 0.047). Time to ROSC was not different between groups (p = 0.054). The 24 -h survival was higher (p = 0.047) and NDS at 24 h was lower (92 ±â€¯175) in the 1-min interval group than in the 2-min interval group (272 ±â€¯190) (p = 0.028). CONCLUSIONS: Defibrillation success and resuscitation outcomes were superior when using a 1-min defibrillation interval in animal models of cardiac arrest.