Mechanical Chest Compression Device for Out-Of-Hospital Cardiac Arrest: A Nationwide Observational Study

BackgroundThere are few studies on the use of a mechanical chest compression (meCC) device during transport in patients with out-of-hospital cardiac arrest (OHCA).ObjectiveThe aim of our study was to compare the performance of an meCC device with that of manual chest compression during transport after OHCA.MethodsThis study used data from the national cardiac arrest registry of patients with OHCA of presumed cardiac etiology. The primary exposure was the use of an meCC device by an Emergency Medical Services provider while transporting a patient to the emergency department. The primary endpoint was good cerebral performance category at discharge. We compared survival and neurologic outcomes between an meCC device group and a manual chest compression group. We also performed an interaction analysis to assess changes in study outcomes of meCC device use by the initial electrocardiogram (ECG) and transport time interval (TTI).ResultsAmong 30,021 adult patients after OHCA with presumed cardiac etiology, an meCC device was used in 2357 (7.6%). After adjustment for possible confounders, there were no significant differences with respect to good neurologic recovery in the outcomes of patients who were treated with an meCC device and those who received manual chest compression (adjusted odds ratio [AOR] 0.66; 95% confidence interval [CI] 0.43–1.02) and survival to discharge (AOR 0.83; 95% CI 0.64–1.06). In the interaction model, the AOR of the meCC device study outcome did not interact with the initial ECG and TTI.ConclusionsThe meCC device did not show better study outcomes than manual compression.     

Association between Weather-Related Factors and Cardiac Arrest of Presumed Cardiac Etiology: A Prospective Observational Study Based on Out-of-Hospital Care Data

Objective: The objective of this study was to determine the association between weather-related factors and out-of-hospital cardiac arrest (OHCA) of presumed cardiac etiology. Methods: This was a prospective observational study performed in a prehospital setting. Data from the Emergency Medical Service in Hamburg (Germany) and data from the local weather station were evaluated over a 5-year period. Weather data (temperature, humidity, air pressure, wind speed) were obtained every minute and matched with the associated rescue mission data. Lowess-Regression analysis was performed to assess the relationship between the above-mentioned weather-related factors and OHCA of presumed cardiac etiology. Additionally, varying measuring-ranges were defined for each weather-related factor in order to compare them with each other with regard to the probability of occurrence of OHCA. Results: During the observation period 1,558 OHCA with presumed cardiac etiology were registered (age: 67 ± 19 yrs; 62% male; hospital admission: 37%; survival to hospital discharge: 6.7%). Compared to moderate temperatures (5 – 25°C), probability of OHCA-occurrence increased significantly at temperatures above 25°C (p = 0.028) and below 5°C p = 0.011). Regarding air humidity, probability of OHCA-occurrence increased below a threshold-value of 75% compared to values above this cut-off (p = 0.006). Decreased probability was seen at moderate atmospheric pressure (1000 hPa – 1020 hPa), whereas increased probability was seen above 1020 hPa (p = 0.023) and below 1000 hPa (p = 0.035). Probability of OHCA-occurrence increased continuously with increasing wind speed (p < 0.001). Conclusions: There are associations between several weather-related factors such as temperature, humidity, air pressure, and wind speed, and occurrence of OHCA of presumed cardiac etiology. Particularly dangerous seem to be cold weather, dry air and strong wind.     

Advanced Airway Type and Its Association with Chest Compression Interruptions During Out-of-Hospital Cardiac Arrest Resuscitation Attempts

Objective: To assess interruptions in chest compressions associated with advanced airway placement during cardiopulmonary resuscitation (CPR) of out-of-hospital cardiac arrest (OHCA) victims. Methods: The method used was observational analysis of prospectively collected clinical and defibrillator data from 339 adult OHCA victims, excluding victims with <5 minutes of CPR. Interruptions in CPR, summarized by chest compression fraction (CCF), longest pause, and the number of pauses greater than 10 seconds, were compared between patients receiving bag valve mask (BVM), supraglottic airway (SGA), endotracheal intubation (ETI) via direct laryngoscopy (DL), and ETI via video laryngoscopy (VL). Secondary outcomes included first pass success and the effect of multiple airway attempts on CPR interruptions. Results: During the study period, paramedics managed 23 cases with BVM, 43 cases with SGA, 148 with DL, and 125 with VL. There were no statistically significant differences between the airway groups with regard to longest compression pause (BVM 18 sec [IQR 11–33], SGA 29 sec [IQR 15–65], DL 26 sec [IQR 12–59], VL 22 sec [IQR 14–41]), median number of pauses greater than 10 seconds (BVM 2 [IQR 1–3], SGA 2 [IQR 1–3], DL 2 [IQR 1–4], VL 2 [IQR 1–3]), or CCF (0.92 for all groups). However, each additional attempt following failed initial DL was associated with an increase in the risk of additional chest compression pauses (relative risk 1.29, 95% confidence interval 1.02–1.64). Such an association was not observed with additional attempts using VL or SGA. First pass success was highest with SGA (77%), followed by between DL (68%) and VL (67%); these differences were not statistically significant. Conclusions: While summary measures of chest compression delivery did not differ significantly between airway classes in this observational study, repeated attempts following failed initial DL during cardiopulmonary resuscitation were associated with an increase in the number of pauses in chest compression delivery observed     

现场早期头部低温治疗对心肺复苏成功率及神经功能的影响

目的：探讨在复苏现场对心搏骤停（CA）患者采用冰帽进行头部早期保存性低温治疗的可行性．及其对患者复苏成功率及神经功能预后的影响。方法：将2011年1月-2013年1月收治的院外CA患者48例随机分为早期低温治疗组25例和对照组23例,比较两组自主循环恢复率、存活出院率、存活患者神经功能评分。结果：头部保存性低温治疗有效地降低耳温,明显改善存活患者的GCS评分,并在一定程度上改善了出院存活率。结论：复苏现场进行头部早期保存性低温治疗可改善复苏后存活患者的神经功能预后。     

Timing and Identification of the Cause and Treatment of a Cardiac Arrest: A Potential Survival Benefit

ObjectiveThe aim of this study was to evaluate how mobile medical teams (MMTs) search for the etiology of a cardiac arrest (CA) and to investigate the association between the discovery of etiology and patient outcome.Subjects and MethodsResuscitations of all adult patients who experienced an in- or out-of-hospital CA between 2016 and 2018 were video recorded. All video recordings were reviewed. The time to start of “cause analysis” and time to treatment by the MMT were analyzed. Also, investigations performed during etiologic evaluation were examined: heteroanamnesis, medical history-taking, clinical examinations, technical investigations, and the use of the 4Hs and 4Ts method.ResultsOf the 139 CA events included in this study, the MMTs performed etiologic evaluation in only 75% of the resuscitations, and in 20% of the evaluations, they did not use the recommended 4Hs and 4Ts method. Medical history-taking and heteroanamnesis were performed in the large majority, but often without clear cause. A presumptive etiology was found in 46.8% of out-of-hospital CAs and 65.2% of in-hospital CAs. A significant association was found between return of spontaneous circulation and the discovery of presumable etiology for out-of-hospital CAs (p < 0.001). The median time to treatment was 492 s (recommended: 130–250 s) for nonshockable rhythms and 422 s (recommended: 270–390 s) for shockable rhythms, up to twice the time advised according to the guidelines.ConclusionThe current approach for etiologic evaluation is not ideal. Further research is needed to establish a more structured and simplified approach.     

Comparison of Airway Management Methods in Entrapped Patients: A Manikin Study

Introduction: Endotracheal intubation remains one of the most challenging skills in prehospital care. There is a minimal amount of data on the optimal technique to use when managing the airway of an entrapped patient. We hypothesized that use of a blindly placed device would result in both the shortest time to airway management and highest success rate. Methods: A difficult airway manikin was placed in a cervical collar and secured upside down in an overturned vehicle. Experienced paramedics and prehospital registered nurses used four different methods to secure the airway: direct laryngoscopy, digital intubation, King LT-D, and CMAC video laryngoscopy. Each participant was given three opportunities to secure the airway using each technique in random order. A study investigator timed each attempt and confirmed successful placement, which was determined upon inflation of the manikin's lungs. Intubation success rates were analyzed using a general estimating equations model to account for repeated measures and a linear mixed effects model for average time. Results: Twenty-two prehospital providers participated in the study. The one-pass success rate for the King LT-D was significantly higher than direct laryngoscopy (OR 0.048, CI 0.006–0.351, p < 0.01) and digital intubation (OR 0.040, CI 0.005–0.297, p < 0.01). However, there was no statistical difference between the one-pass success rate of the King LT-D and CMAC video laryngoscopy (OR 0.302, 95% CI 0.026–3.44, p = 0.33). The one-pass median placement time of the King LT-D (22 seconds, IQR 17–26) was significantly lower (p < 0.001) than direct laryngoscopy (60 seconds, IQR 42–75), digital intubation (38 seconds, IQR 26–74), and the CMAC (51 seconds, IQR 43–76). Conclusions: In this study, while the King LT-D offered the quickest airway placement, success rates were not significantly greater than intubation using the CMAC video laryngoscope. Intubation using direct laryngoscopy and digital intubation were less successful and took more time. Use of a blindly placed device or a video laryngoscope may provide the best avenues for airway management of entrapped patients.     

Prevalence, Therapeutic Response, and Outcome of Ventricular Tachycardia in the Out-of-hospital Setting: A Comparison of Monomorphic Ventricular Tachycardia, Polymorphic Ventricular Tachycardia, and Torsades de Pointes

OBJECTIVE: To investigate out-of-hospital ventricular tachycardia (VT) cardiac arrest patients, comparing the prevalences and outcomes of the following VT subtypes among this population: monomorphic VT (MVT), polymorphic VT (PVT), and torsades de pointes (TdP, PVT with a prolonged QT interval). METHODS: This was a retrospective review from a fire department-based paramedic system of nontraumatic VT cardiac arrest patients (January 1991 to December 1994) with a supraventricular perfusing rhythm (SVPR) at some time during out-of-hospital care, with a measurable QT interval. QT interval was measured from an SVPR, and corrected QT interval (QTc) was calculated and considered prolonged if > 0.45 sec. VT was classified as polymorphic or monomorphic. TdP was defined as PVT with a prolonged QT interval. RESULTS: 196 patients were identified; six were excluded due to incomplete medical records, leaving 190 who met inclusion criteria and were used for data analysis. 117 (62%) patients had MVT, while 73 (38%) patients had PVT; of the 73 patients with PVT, 37 (51%) had normal QTc (non-TdP PVT) and 36 (49%) had prolonged QTc (TdP PVT). 97 (51%) patients had prolonged QTc (PQTc). Regardless of VT type (i.e., MVT vs PVT), 97 (51%) patients had prolonged QTc, with a mean QTc of 0.476+/-0.15 seconds prearrest and 0.464+/-12 seconds postarrest. Patients with PQTc were not more likely to have PVT (70 [37%] vs 76 [40%]; p = 0.705). No significant difference with respect to paramedic-witnessed arrests in each VT morphology group and each QT group was found. The overall hospital discharge rate was 28.4%. Regardless of VT type, patients had similar rates of out-of-hospital return of spontaneous circulation (ROSC) and hospital discharge; patients with PQTc were less likely to be discharged from the hospital (19.6% vs 37.6%; p = 0.01). 27.8% of TdP and 26.8% of non-TdP patients were discharged (p = 0.912). CONCLUSIONS: In this population of out-of-hospital VT arrest patients, MVT is the most common form of VT encountered; PVT and the subtype TdP are also seen in this population with approximately equal frequencies. All three rhythm types demonstrate similar responses to standard Advanced Cardiac Life Support therapy with equal rates of out-of-hospital ROSC and hospital discharge. PQTc may be a marker of poor clinical outcome in patients with out-of-hospital VT arrest.     

A Meta-Analysis of Prehospital Airway Control Techniques Part I: Orotracheal and Nasotracheal Intubation Success Rates

Abstract

Background. Airway management is a key component of prehospital care for seriously ill and injured patients. Although endotracheal intubation has been a commonly performed prehospital procedure for nearly three decades, the safety and efficacy profile of prehospital intubation has been challenged in the last decade. Reported intubation success rates vary widely, and established benchmarks are lacking. Objective. We sought to determine pooled estimates for oral endotracheal intubation (OETI) and nasotracheal intubation (NTI) placement success rates through a meta-analysis of the literature. Methods. We performed a systematic literature search for all English-language articles reporting placement success rates for prehospital intubation. Studies of field procedures performed by prehospital personnel from any nation were included. All titles were reviewed independently by two authors using prespecified inclusion criteria. Pooled estimates of success rates for each airway technique, including drug-facilitated intubation (DFI) and rapid-sequence intubation (RSI), were calculated using a random-effects model. Historical trends were evaluated using meta-regression. Results. Of 2,005 identified titles reviewed, 117 studies addressed OETI and 23 addressed NTI, encompassing a total of 57,132 prehospital patients. There was substantial interrater reliability in the review process (kappa = 0.81). The pooled estimates (and 95% confidence intervals [CIs]) for intervention success for nonphysician clinicians were as follows: overall non-RSI/non-DFI OETI success rate: 86.3% (82.6%–89.4%); OETI for non–cardiac arrest patients: 69.8% (50.9%–83.8%); DFI 86.8% (80.2%–91.4%); and RSI 96.7% (94.7%–98.0%). For pediatric patients, the paramedic OETI success rate was 83.2% (55.2%–95.2%). The overall NTI success rate for nonphysician clinicians was 75.9% (65.9%–83.7%). The historical trend of OETI reflects a 0.49% decline in success rates per year. Conclusions. We provide pooled estimates of placement success rates for prehospital airway interventions. For some patient and clinician characteristics, OETI has relatively low success rates. For nonarrest patients, DFI and RSI appear to increase success rates. Across all clinicians, NTI has a low rate of success, raising questions about the safety and efficacy of this procedure.     

The Effectiveness of Intramuscular Dexmedetomidine on Hemodynamic Responses During Tracheal Intubation and Anesthesia Induction of Hypertensive Patients: A Randomized, Double-Blind, Placebo-Controlled Study

Background: Hypertensive patients are at risk for increased hemodynamic response to tracheal intubation. Sympatholytic drugs administered during the preinduction period may prevent adverse events.Objective: We assessed the effectiveness of a single preinduction IM bolus dose of dexmedetomidine (DMED) 2.5 μg/kg in attenuating hemodynamic responses to tracheal intubation and rapid-sequence anesthesia induction in hypertensive patients treated with angiotensin-converting enzyme inhibitors.Methods: Adult patients (American Society of Anesthesiologists classification II and III) with essential hypertension, scheduled for elective abdominal or gynecologic surgery, were enrolled in this randomized, double-blind, placebo-controlled study. Patients were assigned to i of 2 groups: the DMED group received IM DMED 2.5 μg/kg and the placebo group received IM saline 0.9% 45 to 60 minutes before induction of anesthesia. General anesthesia was induced with thiopental, fentanyl, and vecuronium and maintained with a sevoflurane-nitrous oxide-oxygen mixture. Hemodynamic values were recorded before (baseline) and after anesthesia induction, before endotracheal intubation, and 1, 3, and 5 minutes after intubation. The patients were monitored for hypotension (systolic arterial pressure [SAP] decreased ≥25% from baseline or to <90 mm Hg) or bradycardia (heart rate [HR] decreased ≥25% from baseline or to <50 beats/min).Results: Nine hundred sixty patients were assessed for enrollment during a 6-month period. Sixty patients (49 women, 11 men; mean [SD] age, 59.16 [8.39] years) were eligible for the study. There were no significant differences in baseline hemodynamic values between the groups. SAP and diastolic arterial pressure (DAP) before anesthesia induction, 1 and 3 minutes after intubation, and DAP 1 minute after intubation were significantly lower in the DMED group than in the placebo group (all, P < 0.05). There were no significant between-group differences in SAP or DAP 5 minutes after intubation. HR before anesthesia induction, before intubation, and 1, 3, and 5 minutes after intubation were lower in the DMED group than in the control group (all, P < 0.05). In the DMED group, SAP after intubation, DAP before intubation, 3 and 5 minutes after intubation, HR before induction, before intubation, and 3 and 5 minutes after intubation were significantly decreased compared with baseline values (all, P < 0.05). In the control group, SAP at all times, DAP before intubation, 1, 3, and 5 minutes after intubation, HR before intubation, and 3 and 5 minutes after intubation were significantly decreased compared with baseline values (all, P < 0.05). Hypotension and bradycardia were observed together in 3 patients, and hypotension alone was observed in 1 patient 3 minutes after intubation in the DMED group; hypotension was observed in 1 patient at 3 minutes after intubation in the control group.Conclusion: The results of this study suggest that IM DMED 2.5 μg/kg administered 45 to 60 minutes before anesthesia induction attenuated, but did not completely prevent, hemodynamic responses to tracheal intubation in these patients with essential hypertension.     

Survival and Rearrest in out-of-Hospital Cardiac Arrest Patients with Prehospital Return of Spontaneous Circulation: A Prospective Multi-Regional Observational Study

Abstract

Objective

We aimed to determine the factors associated with rearrest after prehospital return of spontaneous circulation (ROSC) and examine the factors associated with survival despite rearrest.     

Women Are Less Likely to Survive AMI Presenting With Out-of-Hospital Cardiac Arrest: A Nationwide Study

ObjectiveTo assess the impact of patient’s sex on outcomes and management of acute myocardial infarction (AMI) patients presenting with out-of-hospital cardiac arrest (OHCA).Patients and MethodsWe conducted a population-based retrospective cohort study in AMI patients admitted with OHCA between 2010 and 2017 from the Myocardial Ischaemia National Audit Project (MINAP) registry. We used multivariable logistic regression models to evaluate the role of sex as a predictor of clinical outcomes and treatment strategy.ResultsOf 16,278 patients, women constituted almost one-quarter of the population (n=3710 [22.7%]). Women were older (median age 69 [IQR, 57-79] years vs 63 [IQR, 54-72] years, P<.001), experienced longer call-to-hospital-arrival time (median, 1.2 hours vs 1.1 hours; P=.008), were less likely to present with shockable rhythm (86.8% vs 91.5%, P<.001), and less likely to receive dual antiplatelet therapy (73.8% vs 78.6%, P<.001), beta blockers (64.7% vs 72.3%, P<.001), angiotensin-converting enzyme inhibitors (49.0% vs 55.3%, P<.001), coronary angiography (73.7% vs 83.3%, P<.001), and percutaneous coronary intervention (37.5% vs. 40.7%, p 0.004). After adjusting for patient characteristics and management, women had significantly higher odds of in-hospital death compared with men (odds ratio [OR], 1.3; 95% CI, 1.1 to 1.5) and lower odds of receiving coronary angiography (OR, 0.67; 95% CI, 0.59 to 0.75) and coronary artery bypass graft (OR, 0.28; 95% CI, 0.19 to 0.40).ConclusionWomen were less likely to survive following OHCA secondary to AMI. Hospital protocols that minimize physician bias and improve women-physician communication are needed to close this gap.     

Association of Physical Activity With Primary Cardiac Arrest Risk in the General Population: A Nationwide Cohort Study of the Dose-Response Relationship

ObjectiveTo quantify the dose-response relationship between moderate to vigorous physical activity and primary cardiac arrest (PCA).Patients and MethodsThere were 504,840 participants older than 18 years who underwent the Korean National Health Screening Program, including a self-administered questionnaire for physical activity from January 1, 2009, through December 31, 2014. Physical activity levels were converted into metabolic equivalent tasks (METs) per week and categorized to correspond with multiples of public health recommendations. We evaluated the quantitative and categorical dose-response relationship between physical activity and PCA.ResultsA curvilinear dose-response relationship between physical activity and PCA was observed; the benefits started at two-thirds (5 MET-hour/week) of the United States and World Health Organization guidelines–recommended minimum (7.5 MET-hour/week) and continued to 5 times (40 MET-hour/week) the recommended minimum (P nonlinearity <.001). The largest benefit was noted at a level of 2 to 3 times the recommended minimum (hazard ratio, 0.6; 95% CI, 0.4 to 0.8). In addition, there was no evidence of an increased PCA risk at a level more than 5 times the recommended minimum (hazard ratio, 0.7; 95% CI, 0.5 to 1.1). These associations were consistent regardless of age, sex, body mass index, comorbid conditions, and estimated 10-year risk for cardiovascular disease.ConclusionThe beneficial effect of physical activity on PCA started at two-thirds of the recommended minimum and continued to 5 times the recommended minimum. No excess risk for PCA was present among individuals with activity levels more than 5 times the recommended minimum regardless of cardiovascular disease or lifestyle risk factor presence.     

A Comparison of the Speed,Success Rate,and Retention of Rescue Airway Devices Placed by First-responder Emergency Medical Technicians: A High-fidelity Human Patient Simulation Study

Background

Current airway management for most first-responder basic emergency medical technicians (EMT-Bs) does not include the use of blind-advanced-airway devices.

Objective

To compare the speed, success rates, and skill retention with which EMT-Bs providers can place three blind-advanced-airway devices.

Methods

Prospective study of 43 EMT-Bs trained in the use of the Esophageal-Tracheal-Combitube^® (ETC), King LT^® (KLT), and Laryngeal Mask Airway^™ (LMA). The time it took each participant to place each device correctly and ventilate a human patient simulator was assessed. Primary outcome measures were the success rate of proper insertion for each device and time interval from initiation of mouth insertion to initiation of chest rise. To assess skill retention, at 3 months the providers were reassessed under exact conditions.

Results

At Day 1, time required to place an ETC, LMA, and KLT were 32.7 ± 12.3, 19.2 ± 6.2, and 20.1 ± 6.6 s, respectively. Using paired t-tests, LMA and KLT were faster than ETC, p < 0.0001. At 3 months, pair-wise comparisons showed the ETC took longer to place than the KLT and LMA, p < 0.0001; and the LMA took longer to place than the KLT, p = 0.0034 (36.4 ± 13.1 ETC, 24.8 ± 12.4 LMA, 19.0 ± 6.9 KLT). There was no statistical difference of failures in placing any device.

Conclusions

Comparison of three rescue airway devices placed by EMT-Bs providers showed that it takes significantly longer to place an ETC compared to an LMA and KLT both on Day 1 and 3 months later. Three-month retention studies revealed that it took significantly longer to place an LMA compared to the KLT.     

Association between body mass index and clinical outcomes of patients after cardiac arrest and resuscitation: A meta-analysis

Background

Obesity as one of the risk factors for cardiovascular diseases increases mortality in general population. Several clinical studies investigated clinical outcomes in patients with different body mass index (BMI) after cardiac arrest (CA). Controversial data regarding BMI on clinical outcomes in those patients exist in those studies. Therefore, we conducted a meta-analysis to evaluate the effect of BMI on survival condition and neurological prognosis in those patients.

Newer P2Y12 Inhibitors vs Clopidogrel in Acute Myocardial Infarction With Cardiac Arrest or Cardiogenic Shock: A Systematic Review and Meta-analysis

ObjectiveTo evaluate the outcomes, safety, and efficacy of dual antiplatelet therapy (DAPT) with newer P2Y₁₂ inhibitors compared with clopidogrel in patients with acute myocardial infarction (AMI) complicated by cardiac arrest (CA) or cardiogenic shock (CS).Patients and MethodsMEDLINE, EMBASE, and the Cochrane Library were queried systematically from inception to January 2021 for comparative studies of adults (≥18 years) with AMI-CA/CS receiving DAPT with newer P2Y₁₂ inhibitors as opposed to clopidogrel. We compared outcomes (30-day or in-hospital and 1-year all-cause mortality, major bleeding, and definite stent thrombosis) of newer P2Y₁₂ inhibitors and clopidogrel in patients with AMI-CA/CS.ResultsEight studies (1 randomized trial and 7 cohort studies) comprising 1100 patients (695 [63.2%] receiving clopidogrel and 405 [36.8%] receiving ticagrelor or prasugrel) were included. The population was mostly male (68.5%-86.7%). Risk of bias was low for these studies, with between-study heterogeneity and subgroup differences not statistically significant. Compared with the clopidogrel cohort, the newer P2Y₁₂ cohort had lower rates of early mortality (odds ratio [OR], 0.60; 95% CI, 0.45 to 0.81; P=.001) (7 studies) and 1-year mortality (OR, 0.51; 95% CI, 0.36 to 0.71; P<.001) (3 studies). We did not find a significant difference in major bleeding (OR, 1.21; 95% CI, 0.71 to 2.06; P=.48) (6 studies) or definite stent thrombosis (OR, 2.01; 95% CI, 0.63 to 6.45; P=.24) (7 studies).ConclusionIn patients with AMI-CA/CS receiving DAPT, compared with clopidogrel, newer P2Y₁₂ inhibitors were associated with lower rates of early and 1-year mortality. Data on major bleeding and stent thrombosis were inconclusive.