Collapse-related traumatic intracranial hemorrhage following out-of-hospital cardiac arrest: A multicenter retrospective cohort study.

Background: Sudden loss of consciousness as a result of cardiac arrest can cause severe traumatic head injury. Collapse-related traumatic intracranial hemorrhage (CRTIH) following out-of-hospital cardiac arrest (OHCA) may be linked to poor neurological outcomes; however, there is a paucity of data on this entity. This study aimed to investigate the frequency, characteristics, and outcomes of CRTIH following OHCA. Methods: Adult patients treated post-OHCA at 5 intensive care units who had head computed tomography (CT) scans were included in the study. CRTIH following OHCA was defined as a traumatic intracranial injury from collapse due to sudden loss of consciousness associated with OHCA. Patients with and without CRTIH were compared. The primary outcome assessed was the frequency of CRTIH following OHCA. Additionally, the clinical features, management, and consequences of CRTIH were analyzed descriptively. Results: CRTIH following OHCA was observed in 8 of 345 enrolled patients (2.3%). CRTIH was more frequent after collapse outside the home, from a standing position, or due to cardiac arrest with a cardiac etiology. Intracranial hematoma expansion on follow up CT was seen in 2 patients; both received anticoagulant therapy, and one required surgical evacuation. Three patients (37.5%) with CRTIH had favorable neurological outcomes 28 days after collapse. Conclusions: Despite its rare occurrence, physicians should pay special attention to CRTIH following OHCA during the post-resuscitation care period. Larger prospective studies are warranted to provide a more explicit picture of this clinical condition.

D-dimer measurement is useful irrespective of time from the onset of acute aortic syndrome symptoms.

BACKGROUND: In acute aortic syndrome (AAS) screening, D-dimer is a well-established biomarker whose usefulness has been scarcely studied with respect to its measurement timing. We aimed to evaluate the effectiveness of D-dimer-based AAS screening focused on the time interval between AAS onset and D-dimer measurement. METHODS: We retrospectively analyzed consecutive patients diagnosed with AAS who visited our hospital between 2011 and 2021. For the primary analysis, we divided patients according to the quartiles of the time interval between AAS symptom onset and D-dimer measurement. D-dimer level ≥ 0.5 µg/mL and age-adjusted D-dimer ≥ [age (years) × 0.01] µg/mL (minimum of 0.5 µg/mL) were defined as positive. The primary endpoint was the comparative ability of D-dimer to detect AAS within and between each time quartile. In an exploratory secondary analysis, we reported patient and AAS characteristics in the subgroup of patients who underwent repeat D-dimer measurement within 48 h of the first D-dimer measure. RESULTS: The 273 AAS patients were divided into four groups based on quartiles of the time interval (Group 1, ≤1 h; Group 2, 1-2 h; Group 3, 2-5 h; and Group 4, >5 h). There were no significant differences in D-dimer levels or in the proportions with positive D-dimer (Group 1: 97%, Group 2: 96%, Group 3: 99%, Group 4: 99%; P = 0.76) or positive age-adjusted D-dimer (Group 1: 96%, Group 2: 90%, Group 3: 96%, Group 4: 97%; P = 0.32) between the groups. Of the 147 patients who had D-dimer re-measured, nine had negative D-dimer levels on either the primary or secondary measurement. Of these nine patients, eight had AAS with a thrombosed false lumen and one with a patent false lumen had a short length of dissection. In all nine patients, D-dimer levels remained low (maximum of 1.4 µg/mL). CONCLUSION: D-dimer levels were elevated from the early stages of AAS. The clinical utility of D-dimer is not affected by the time interval from AAS onset to D-dimer measurement, but rather is influenced by AAS characteristics.

Transient return of spontaneous circulation related to favourable outcomes in out-of-hospital cardiac arrest patients resuscitated with extracorporeal cardiopulmonary resuscitation: A secondary analysis of the SAVE-J II study.

Aim: This study aimed to investigate the relationship between transient return of spontaneous circulation (ROSC) before extracorporeal membrane oxygenation (ECMO) initiation and outcomes in out-of-hospital cardiac arrest (OHCA) patients, who were resuscitated with extracorporeal cardiopulmonary resuscitation (ECPR). Methods: This study was a secondary analysis of the SAVE-J II study, which was a retrospective multicentre registry study involving 36 participating institutions in Japan. We classified patients into two groups according to the presence or absence of transient ROSC before ECMO initiation. Transient ROSC was defined as any palpable pulse of ≥1 min before ECMO initiation. The primary outcome was favourable neurological outcomes (cerebral performance categories 1-2). Results: Of 2,157 patients registered in the SAVE-J II study, 1,501 met the study inclusion criteria; 328 (22%) experienced transient ROSC before ECMO initiation. Patients with transient ROSC had better outcomes than those without ROSC (favourable neurological outcome, 26% vs 12%, P < 0.001; survival to hospital discharge, 46% vs 24%, respectively; P < 0.001). A Kaplan-Meier plot showed better survival in the transient ROSC group (log-rank test, P < 0.001). In multiple logistic analyses, transient ROSC was significantly associated with favourable neurological outcomes and survival (favourable neurological outcomes, adjusted odds ratio, 3.34 [95% confidence interval, 2.35-4.73]; survival, adjusted odds ratio, 3.99 [95% confidence interval, 2.95-5.40]). Conclusions: In OHCA patients resuscitated with ECPR, transient ROSC before ECMO initiation was associated with favourable outcomes. Hence, transient ROSC is a predictor of improved outcomes after ECPR.

Extracorporeal cardiopulmonary resuscitation in adult patients with out-of-hospital cardiac arrest: a retrospective large cohort multicenter study in Japan.

BACKGROUND: The prevalence of extracorporeal cardiopulmonary resuscitation (ECPR) in patients with out-of-hospital cardiac arrest (OHCA) has been increasing rapidly worldwide. However, guidelines or clinical studies do not provide sufficient data on ECPR practice. The aim of this study was to provide real-world data on ECPR for patients with OHCA, including details of complications. METHODS: We did a retrospective database analysis of observational multicenter cohort study in Japan. Adult patients with OHCA of presumed cardiac etiology who received ECPR between 2013 and 2018 were included. The primary outcome was favorable neurological outcome at hospital discharge, defined as a cerebral performance category of 1 or 2. RESULTS: A total of 1644 patients with OHCA were included in this study. The patient age was 18-93 years (median: 60 years). Shockable rhythm in the initial cardiac rhythm at the scene was 69.4%. The median estimated low flow time was 55 min (interquartile range: 45-66 min). Favorable neurological outcome at hospital discharge was observed in 14.1% of patients, and the rate of survival to hospital discharge was 27.2%. The proportions of favorable neurological outcome at hospital discharge in terms of shockable rhythm, pulseless electrical activity, and asystole were 16.7%, 9.2%, and 3.9%, respectively. Complications were observed during ECPR in 32.7% of patients, and the most common complication was bleeding, with the rates of cannulation site bleeding and other types of hemorrhage at 16.4% and 8.5%, respectively. CONCLUSIONS: In this large cohort, data on the ECPR of 1644 patients with OHCA show that the proportion of favorable neurological outcomes at hospital discharge was 14.1%, survival rate at hospital discharge was 27.2%, and complications were observed during ECPR in 32.7%.

Details of Targeted Temperature Management Methods for Patients Who Had Out-of-Hospital Cardiac Arrest Receiving Extracorporeal Cardiopulmonary Resuscitation: A Questionnaire Survey.

This study aimed to precisely describe the details of targeted temperature management (TTM) following extracorporeal cardiopulmonary resuscitation (ECPR) in patients with out-of-hospital cardiac arrest (OHCA). A questionnaire to examine the TTM details following ECPR was distributed to 36 medical institutions that participated in the Study of Advanced life support for Ventricular fibrillation with Extracorporeal circulation in Japan (SAVE-J) II study. The survey was conducted using an anonymous questionnaire through the Internet and was distributed in January 2021 and collected in February 2021. Practical TTM methods (induction, maintenance, and rewarming duration) and monitoring and management methods, such as target levels, drugs, left ventricular decompression therapy, nutrition, and rehabilitation therapy, were recorded. We received responses from all 36 institutions. The target temperature was initiated at 34°C in 72.2% of institutions. In ∼90% of institutions, the maintenance duration was 24 hours, which was also the leading duration of rewarming 24 hours (38.9%), followed by 48 hours (30.6%). Electroencephalogram is routinely applied in only 13.9% of institutions. Prophylactic antibiotics were used in 58.6% of institutions. Enteral nutrition during TTM is consistently initiated in 27.8% of institutions and 33.3% of institutions initiated enteral nutrition for patients without catecholamine requirements. The 24-48 hours (55.6%) was the leading period of initiating early rehabilitation, followed by <24 hours. This survey described the details of the current practice for treating patients with OHCA by TTM following ECPR. Since various factors were undetermined in the TTM, randomized controlled trials will be necessary to resolve issues during TTM following ECPR.

Blood cultures should be collected for acute cholangitis regardless of severity.

BACKGROUND: Despite the high frequency of bacteremia in acute cholangitis, the indications for blood cultures and the relationship between the incidence of bacteremia and severity of acute cholangitis have not been well established. This study examined the association between the 2018 Tokyo Guidelines (TG18) severity grading for acute cholangitis and incidence of bacteremia to identify the need for blood cultures among patients with acute cholangitis in each severity grade. METHODS: Patients with acute cholangitis who visited our emergency department between 2019 and 2020 were retrospectively investigated. Patients administered antibiotics within 48 h of hospital arrival, whose prothrombin time-international normalized ratios were not measured, or who were suspected of false bacteremia were excluded. RESULTS: Out of the included 358 patients with acute cholangitis, blood cultures were collected from 310 (87%) patients, of which 148 (48%) were complicated with bacteremia. As the TG18 severity grading increased, the frequency of bacteremia increased (Grade I, 35% [59/171]; Grade II, 59% [48/82]; Grade III, 74% [42/57]; P <0.001). Agreement with the TG18 diagnostic criteria (unfulfilled, suspected, or definite) was not different between patients with and without bacteremia; however, 36% (14/39) of the patients with "unfulfilled" criteria were complicated with bacteremia. CONCLUSIONS: As the severity of acute cholangitis increased, the frequency of bacteremia increased; however, the incidence of bacteremia was high even in mild cases and cases that did not meet the TG18 diagnostic criteria. Blood cultures should be collected regardless of the severity of acute cholangitis for patients who visit the emergency department.

Potential of unenhanced computed tomography as a screening tool for acute aortic syndromes.

AIMS: Contrast-enhanced computed tomography (CE-CT) is the gold standard for diagnosing acute aortic syndromes (AAS). Unenhanced computed tomography (unenhanced-CT) also provides specific findings for AAS; however, its diagnostic ability is not well discussed. This study aims to evaluate the potential of unenhanced-CT as an AAS screening tool. METHODS AND RESULTS: We retrospectively examined AAS patients who visited our hospital between 2011 and 2021 to validate the diagnostic value of unenhanced-CT alone and along with the aortic dissection detection risk score (ADD-RS) plus D-dimer. Acute aortic syndrome was assessed as detectable using unenhanced-CT with any of the following findings: pericardial haemorrhage, high-attenuation haematoma, and displacement of intimal calcification or a flap. Of the 316 AAS cases, 292 (92%) were detectable with unenhanced-CT. Twenty-four (8%) cases undetectable with unenhanced-CT involved younger patients [median (interquartile range), 45 (42-51) years vs. 72 (63-80) years, P < 0.001] and patients more frequently complicated with a patent false lumen (79% vs. 42%, P < 0.001). Acute aortic syndrome-detection rate with unenhanced-CT increased with age, reaching 98% (276/282) in those ≥50 years of age and 100% (121/121) in those ≥75 years of age. With the ADD-RS plus D-dimer, there was only one AAS case undetectable with unenhanced-CT among patients ≥50 years of age, except for cases with the ADD-RS ≥1 plus D-dimer levels of ≥0.5 µg/mL. CONCLUSION: Acute aortic syndromes in younger patients and patients with a patent false lumen could be misdiagnosed with unenhanced-CT alone. The combination of the ADD-RS plus D-dimer and unenhanced-CT could minimize AAS misdiagnosis while avoiding over-testing with CE-CT.

Variability of extracorporeal cardiopulmonary resuscitation practice in patients with out-of-hospital cardiac arrest from the emergency department to intensive care unit in Japan.

AIM: A lack of known guidelines for the provision of extracorporeal cardiopulmonary resuscitation (ECPR) to patients with out-of-hospital cardiac arrest (OHCA) has led to variability in practice between hospitals even in the same country. Because variability in ECPR practice has not been completely examined, we aimed to describe the variability in ECPR practice in patients with OHCA from the emergency department (ED) to the intensive care units (ICU). METHODS: An anonymous online questionnaire to examine variability in ECPR practice was completed in January 2020 by 36 medical institutions who participated in the SAVE-J II study. Institutional demographics, inclusion and exclusion criteria, initial resuscitation management, extracorporeal membrane oxygenation (ECMO) initiation, initial ECMO management, intra-aortic balloon pumping/endotracheal intubation/management during coronary angiography, and computed tomography criteria were recorded. RESULTS: We received responses from all 36 institutions. Four institutions (11.1%) had a hybrid emergency room. Cardiovascular surgery was always involved throughout the entire ECMO process in only 14.7% of institutions; 60% of institutions had formal inclusion criteria and 50% had formal exclusion criteria. In two-thirds of institutions, emergency physicians carried out cannulation. Catheterization room was the leading location of cannulation (48.6%) followed by ED (31.4%). The presence of formal exclusion criteria significantly increased with increasing ECPR volume (P for trend <0.001). Intra-aortic balloon pumping was routinely initiated in only 25% of institutions. Computed tomography was routinely carried out before coronary angiography in 25% of institutions. CONCLUSIONS: We described the variability in ECPR practice in patients with OHCA from the ED to the ICU.

Clinical prediction rule is more useful than qSOFA and the Sepsis-3 definition of sepsis for screening bacteremia.

BACKGROUND: Clinical guidelines recommend blood cultures for patients suspected with sepsis and bacteremia. Sepsis-3 task force introduced the new definition of sepsis in 2016; however, the relationship between the Sepsis-3 definition of sepsis and bacteremia remains unclear. This study aimed to investigate how to detect patients who need blood cultures. METHODS: Consecutive patients who visited the emergency department in our hospital with suspected symptoms of bacterial infection and with collected blood culture were retrospectively examined between April and September 2019. The relationship between bacteremia and Sepsis-3 definition of sepsis, and the relationship between bacteremia and clinical scores (quick-Sequential Organ Failure Assessment [qSOFA], systematic inflammatory response syndrome [SIRS], and Shapiro's clinical prediction rule) were investigated. In any scores used, ≥2 points were considered positive. RESULTS: Among the 986 patients who met the inclusion criteria, 171 (17%) were complicated with bacteremia and 270 (27%) were patients with sepsis. Sepsis was more frequent (61% vs. 20%, P < 0.001) and all clinical scores were more frequently positive in patients with bacteremia than in those without (qSOFA, 23% vs. 9%; SIRS, 72% vs. 58%; Shapiro's clinical prediction rule, 88% vs. 49%; P < 0.001). Specificity to predict bacteremia was high in sepsis and positive qSOFA (0.80 and 0.91, respectively), whereas sensitivity was high in positive SIRS and Shapiro's clinical prediction rule (0.72 and 0.88, respectively); however, no clinical definitions and scores had both high sensitivity and specificity. The area under the receiver operating characteristic curves were 0.59 (95% confidence interval, 0.55-0.64), 0.60 (0.56-0.65), and 0.78 (0.74-0.82) in qSOFA, SIRS, and Shapiro's clinical prediction rule, respectively. CONCLUSION: Blood cultures should be obtained for patients with sepsis and positive qSOFA because of its high specificities to predict bacteremia; however, because of low sensitivities, Shapiro's clinical prediction rule can be more efficiently used for screening bacteremia.

Diagnostic ability of a newly developed system for recognition of cardiac arrests.

BACKGROUND: Early recognition of cardiac arrest is essential for increasing the likelihood of successful resuscitation. However, many factors could obstruct the recognition of cardiac arrest and delay the delivery of cardiopulmonary resuscitation and automated external defibrillator use. We have developed a new system using infrared light to recognize cardiac arrests during emergency. The aim of this study was to evaluate whether cardiac arrests could be appropriately diagnosed by this system in clinical practice. METHODS: During the initial treatment patients 18 years old and older with unconscious level of 300 on Japan Coma Scale were prospectively registered from May 1st 2016 through May 31st 2017 (University Hospital Medical Information Network-Clinical Trials Registry 000022137). The settings for this study were two critical care medical centers in Osaka Prefecture and two suburban emergency medical services in Chiba Prefecture and Osaka Prefecture in Japan. We evaluated each patient, using the diagnosis of cardiac arrest by relevant physicians or emergency medical services personnel as the "gold standard". Finally, the sensitivity and specificity of the system in understanding whether the patient has cardiac arrest were assessed. RESULTS: Out of 207 unconscious patients, 163 patients were diagnosed as suffering from cardiac arrest and 44 patients were identified as experiencing pulsating cardiac rhythm. The developed system for diagnosing cardiac arrest when used within 10 s from the activation of the system had a sensitivity of 100% and a specificity of 55.2%. Additionally, the system had a sensitivity of 100% and a specificity of 63.6% for diagnosing cardiac arrest when used within 20 s from activation. CONCLUSIONS: The newly developed system has 100% sensitivity in detecting cardiac arrests within 10 s from activation of the system in emergency settings. This developed system could help bystanders to promptly initiate resuscitation.

Optimal extracorporeal cardiopulmonary resuscitation inclusion criteria for favorable neurological outcomes: a single-center retrospective analysis.

AIM: Although age ≤75 years, witnessed arrest, shockable initial cardiac rhythm, and short cardiac arrest duration are commonly cited inclusion criteria for extracorporeal cardiopulmonary resuscitation (ECPR), these criteria are not well-established, and ECPR outcomes remain poor. We aimed to evaluate whether the aforementioned inclusion criteria are appropriate for ECPR, and estimate the improvements in prognoses associated with their fulfillment. METHODS: Between October 2009 and December 2017, we retrospectively examined consecutive out-of-hospital cardiac arrest patients who were admitted to our hospital and received ECPR. We established four ECPR inclusion criteria: age ≤75 years, witnessed arrest, shockable initial cardiac rhythm, and call-to-hospital arrival time ≤45 min, and also evaluated the relationship between these criteria and patient outcomes. RESULTS: During the study period, 1,677 out-of-hospital cardiac arrest patients were admitted to our hospital, and 156 (9%) with ECPR were examined. The proportion of favorable neurological outcomes was 15% (24/156). However, when the study population was limited to individuals who fulfilled all four criteria, 27% (15/55) had favorable neurological outcomes; only one patient had favorable outcomes when two or more criteria were fulfilled. There was a significant positive linear correlation between the proportion of cases with favorable neurological outcomes and fulfillment of the four criteria (P = 0.005, r = 0.975). CONCLUSION: Fulfillment of at least three of the aforementioned criteria could yield improved ECPR outcomes.

Low-flow time is associated with a favorable neurological outcome in out-of-hospital cardiac arrest patients resuscitated with extracorporeal cardiopulmonary resuscitation.

PROPOSE: The aim of this retrospective study was to investigate the prognostic factors in extracorporeal cardiopulmonary resuscitation (ECPR) patients and to assess their accuracy as predictors of a favorable neurological outcome. MATERIALS AND METHODS: Between October 2009 and December 2017, we retrospectively analyzed witnessed out-of-hospital cardiac arrest patients who were admitted to our hospital and resuscitated with ECPR. We compared the baseline characteristics, pre-hospital clinical course, arrest causes, and blood samples on admission for the favorable and unfavorable outcome groups. RESULTS: Among the 135 patients included, 22 (16%) had a favorable neurological outcome. Low-flow time was shorter (median 38 vs. 48 min, p < 0.001) in the favorable neurological outcome group; in multiple logistic analyses, low-flow time was significantly associated with a favorable neurological outcome (odds ratio, 0.88; 95% confidence interval, 0.82-0.94). The area under the receiver-operating characteristic curve of low-flow time was 0.80 (95% confidence interval, 0.70-0.89), and the cut-off value of 58 min corresponded to a sensitivity of 0.25 and a specificity of 1.0. CONCLUSIONS: In ECPR patients, low-flow time was significantly associated with a favorable neurological outcome, and ECPR should be performed within 58 min of the low-flow time.

In vivo fluorescence bioimaging of ascorbic acid in mice: Development of an efficient probe consisting of phthalocyanine, TEMPO, and albumin.

After a groundbreaking study demonstrated that a high dose of ascorbic acid selectively kills cancer cells, the compound has been tested in the clinic against various forms of cancers, with some success. However, in vivo tracing of intravenously injected ascorbic acid has not been achieved. Herein, we successfully imaged ascorbic acid intravenously injected into mice based on the discovery of a novel, highly sensitive, and appropriately selective fluorescent probe consisting of silicon phthalocyanine (SiPc) and two 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radicals, i.e., R2c. The radicals in this R2c were encapsulated in dimeric bovine serum albumin, and the sensitivity was >100-fold higher than those of other R2c-based probes. Ascorbic acid intravenously injected into mice was efficiently transported to the liver, heart, lung, and cholecyst. The present results provide opportunities to advance the use of ascorbic acid as cancer therapy.

D-dimer predicts bleeding complication in out-of-hospital cardiac arrest resuscitated with ECMO.

PURPOSE: In out-of-hospital cardiac arrest (OHCA) patients resuscitated with veno-arterial extracorporeal membrane oxygenation (VA-ECMO), known as extracorporeal cardiopulmonary resuscitation (ECPR), bleeding is a common complication. The purpose of this study was to assess the risk factors for bleeding complications in ECPR patients. METHODS: We retrospectively analyzed the data for OHCA patients admitted to our hospital and resuscitated with ECPR between October 2009 and December 2016. We compared patients with and without major bleeding (i.e. the Bleeding Academic Research Consortium class≥3 bleeding) within 24h of hospital admission. Patients, whose bleeding complication was not evaluated, were excluded. RESULTS: During the study period, 133 OHCA patients were resuscitated with ECPR, of whom 102 (77%) were included. In total, 71 (70%) patients experienced major bleeding. There were significant differences in age (median 65 vs. 50years, P<0.001), prior antiplatelet therapy (25% vs. 3%, P=0.008), hemoglobin (median 11.6 vs. 12.6g/dL, P=0.003), platelet count (median 125 vs. 155×103/µL, P=0.001), and D-dimer levels on admission (median 18.8 vs. 6.7µg/mL, P<0.001) among patients with and those without major bleeding. Multivariate analysis showed significant associations between major bleeding and D-dimer levels (odds ratio, 1.066; 95% confidence interval, 1.018-1.116). Area under receiver-operating characteristic curve, which describes the accuracy of D-dimer levels in predicting major bleeding, was 0.76 (95% confidence interval, 0.66-0.87). CONCLUSION: D-dimer levels may predict major bleeding in ECPR patients, suggesting that hyperfibrinolysis may be related to bleeding.

Global Registry of Acute Coronary Events risk score predicts mortality and neurological outcome in out-of hospital cardiac arrest.

PURPOSE: The aim of this study was to assess the usefulness of the Global Registry of Acute Coronary Events (GRACE) risk score in predicting in-hospital mortality and neurological outcome of patients resuscitated after out-of-hospital cardiac arrest (OHCA). METHODS: We retrospectively analyzed the data of patients admitted to our hospital between October 2009 and October 2015 with OHCA and shockable initial cardiac rhythm who were resuscitated via conventional cardiopulmonary resuscitation. We calculated the GRACE risk score on admission and assessed its usefulness in predicting in-hospital mortality and neurological outcome. RESULTS: Among 91 patients, 42 (46%) had acute myocardial infarction (AMI), 19 (21%) died in-hospital, and 52 (57%) had favorable neurological outcome. Among all the study patients, GRACE risk score was lower in survivors than in non-survivors (median 211 [interquartile range 176-240] vs. 266 [219-301], p<0.001, respectively) and in favorable than in unfavorable neurological outcome group (202 [167-237] vs. 242 [219-275], p<0.001, respectively). Multivariate analysis showed significant association between GRACE risk score and favorable neurological outcome (odds ratio, 0.975; 95% confidence interval, 0.961-0.990). Areas under receiver-operating characteristic curves, that describe the accuracy of GRACE risk score in predicting in-hospital mortality and favorable neurological outcome, were both 0.79. CONCLUSION: GRACE risk score may predict the in-hospital mortality and neurological outcome associated with resuscitated patients with OHCA and shockable initial cardiac rhythm, regardless of the cause of arrest.

Resistance to conventional cardiopulmonary resuscitation in witnessed out-of-hospital cardiac arrest patients with shockable initial cardiac rhythm.

BACKGROUND: Shockable initial cardiac rhythm is a key predictor of survival after out-of-hospital cardiac arrest (OHCA). However, not all patients with shockable OHCA achieve return of spontaneous circulation (ROSC) via conventional cardiopulmonary resuscitation (CPR). Therefore, we retrospectively analyzed patients with witnessed OHCA and shockable initial cardiac rhythm to identify the resistance factors for conventional CPR. METHODS: We retrospectively analyzed consecutive patients with witnessed OHCA and shockable initial cardiac rhythm who were admitted to our hospital between October 2009 and October 2014. We then compared the baseline characteristics, pre-hospital clinical course, and causes of the cardiopulmonary arrest among patients who achieved ROSC via conventional CPR and patients who did not achieve ROSC via conventional CPR and underwent extracorporeal CPR (ECPR). RESULTS: A total of 85 patients achieved ROSC via conventional CPR (non-ECPR group) and 40 patients did not achieve ROSC via conventional CPR and underwent ECPR (ECPR group). Among these 125 patients, 113 had known causes for their cardiopulmonary arrest, including 66 cases (53%) of acute myocardial infarction (AMI). There were no significant differences in the causes of arrest between the non-ECPR and ECPR cases. However, among the 66 cases of AMI (43 non-ECPR and 23 ECPR), the rate of non-recanalization during the initial coronary angiography was significantly higher among the ECPR cases (non-ECPR: 58% vs. ECPR: 87%; p=0.03). CONCLUSIONS: The major cause of witnessed OHCA with shockable initial cardiac rhythm was AMI, and resistance to conventional CPR was related to continuous myocardial ischemia.