Search Results (233)

Background/Objectives: Missing data in clinical observational studies, such as out-of-hospital cardiac arrest (OHCA) registries, can compromise statistical validity. Single imputation methods are simple alternatives to complete-case analysis (CCA) but do not account for imputation uncertainty. Multiple imputation (MI) is the standard for handling missing-at-random (MAR) data, yet its implementation remains challenging. This study evaluated the performance of MI in association analysis compared with CCA and single imputation methods. Methods: Using a simulation framework with real-world Singapore OHCA registry data (N = 13,274 complete cases), we artificially introduced 20%, 30%, and 40% missingness under MAR. MI was implemented using predictive mean matching (PMM), random forest (RF), and classification and regression trees (CART) algorithms, with 5–20 imputations. Performance was assessed based on bias and precision in a logistic regression model evaluating the association between alert issuance and bystander CPR. Results: CART outperformed PMM, providing more accurate β coefficients and stable CIs across missingness levels. Although K-Nearest Neighbours (KNN) produced similar point estimates, it underestimated imputation uncertainty. PMM showed larger bias, wider and less stable CIs, and in some settings performed similarly to CCA. MI methods produced wider CIs than single imputation, appropriately capturing imputation uncertainty. Increasing the number of imputations had minimal impact on point estimates but modestly narrowed CIs. Conclusions: MI performance depends strongly on the chosen algorithm. CART and RF methods offered the most robust and consistent results for OHCA data, whereas PMM may not be optimal and should be selected with caution. MI using tree-based methods (CART/RF) remains the preferred strategy for generating reliable conclusions in OHCA research. Full article

Introduction: Population aging in Europe is ongoing and linked to poorer outcomes after out-of-hospital cardiac arrest (OHCA), yet age alone should not guide treatment. We aimed to describe age-related survival, identify independent predictors, and develop a predictive model using EMS data. Methods: We analyzed 147,962 adult OHCA cases from the Hungarian National EMS registry. Variables included initial rhythm, witness status, location, and sex. The primary outcome was survival to hospital admission. Multivariable logistic regression assessed independent predictors and age × treatment interactions; performance was evaluated with AUC, Brier score, and cross-validation. Results: Overall survival was 8.8%; elderly patients had lower survival (7.3%) than non-elderly (11.7%, p < 0.001). VF/VT (adjusted OR 5.34), medical personnel witness (OR 4.52), and AED shock (OR 3.52) were the strongest predictors. Age attenuated the survival benefit of VF/VT (interaction OR 0.914) and the protective effect of female sex (interaction OR 0.882; both p < 0.001). Model performance was good (AUC 0.784; Brier 0.0705). Conclusions: Age independently predicts survival after OHCA, but substantial treatment benefits persist in the elderly. Age–treatment interactions support geriatric-tailored resuscitation strategies and potential integration of this high-performing model into clinical decision support systems. Full article

Out-of-hospital cardiac arrest (OHCA) is a major cause of death during mountain activities in the Alpine regions. Due to the time-critical nature of these emergencies and the logistical challenges of remote terrain, emergency medical services (EMS) are investigating the use of unmanned aerial vehicles (UAVs) to deliver automated external defibrillators (AEDs). This study presents a geospatial strategy for optimising AED delivery by UAVs in mountainous environments, using the Province of South Tyrol, Italy, as a model region. A Geographic Information System (GIS) framework was developed to identify suitable sites for vertical drone ports based on terrain, infrastructure, and regulatory constraints. A Low-Altitude-Flight Elevation Model (LAFEM) was implemented to generate obstacle-avoiding, regulation-compliant 3D flight paths using least-cost path analysis. The results identified 542 potential vertical-port locations, covering approximately 49% of South Tyrol within ten minutes of flight, and demonstrated significant time savings for AED delivery in field tests compared with manual and Euclidean routing. These findings show that integrating GIS-based vertical-port placement and terrain-adaptive UAV routing can substantially improve AED accessibility and response times in mountainous regions. The LAFEM model aligns with U-space airspace regulations and supports safe, automated AED deployment for improved outcomes in OHCA emergencies. Full article

Background/Objectives: Early bystander CPR helps to restore perfusion and improves the likelihood of favorable survival and neurological outcome after out-of-hospital cardiac arrest (OHCA). One strategy to improve bystander CPR is the use of crowd-sourcing mobile CPR applications such as PulsePoint, which notifies bystanders of nearby OHCA. In 2019, PulsePoint was deployed in an urban county. Prior to its deployment, bystander CPR rates were 42.9% in this county. This descriptive analysis seeks to analyze bystander intervention after PulsePoint implementation in an urban county. Methods: This retrospective observational study included all PulsePoint activations in Alachua County from June 2020 to September 2023. Patient characteristics and survey data were extracted from EMS patient care reports, hospital electronic medical records, and Pulsepoint dispatch and responder data. Descriptive statistics were used to analyze patient and responder characteristics, PulsePoint activation circumstances, and patient care. Results: Of 225 PulsePoint activations, 95 (42.2%) were confirmed OHCA. Among these, 54 (56.8%) received bystander CPR prior to EMS arrival. Out of 15 prehospital defibrillations, laypersons defibrillated 9 patients (60.0%). There was an average of 3.3 eligible PulsePoint responders within a 0.25-mile radius of the OHCA victim. A majority of PulsePoint survey respondents were formally trained in CPR and automated defibrillator use. Conclusions: The data from our urban EMS experience demonstrate that bystander CPR rates were higher after PulsePoint deployment (56.8%) than before. Our bystander CPR rate was also higher than the national average. Full article

Despite advances in post-cardiac arrest care, mortality and poor neurological outcomes remain common after out-of-hospital cardiac arrest (OHCA). Calcium imbalance is characteristic of post-cardiac arrest syndrome, but its prognostic role is unclear. We retrospectively analyzed 421 OHCA patients treated with targeted temperature management (TTM) (2011–2023). pH-adjusted ionized calcium levels were measured at 0, 12, 24, 48, and 72 h after return of spontaneous circulation (ROSC). Associations with 30-day neurological outcomes and mortality were assessed using multivariable logistic regression with two-stage maximum likelihood estimation. Higher baseline-adjusted ionized calcium levels were significantly associated with better neurological outcomes (Cerebral Performance Category 1–2) and lower 30-day mortality, regardless of calcium infusion or clinical covariates. Each 0.01-unit increase corresponded to 17% lower odds of unfavorable neurological outcome (odds ratio [OR], 0.83; 95% confidence interval [CI], 0.76–0.90) and 10% lower mortality (OR, 0.90; 95% CI, 0.84–0.96). Incorporating longitudinal calcium measurements improved predictive accuracy, raising the area under the curve for neurological outcomes from 0.843 to 0.919. Early post-ROSC ionized calcium levels were independently associated with neurological outcomes and mortality in patients with OHCA treated with TTM. Serial ionized calcium monitoring may serve as a prognostic marker, warranting prospective evaluation of therapeutic implications. Full article

Background/Objectives: Out-of-hospital cardiac arrest (OHCA) has persistently low survival rates. While advanced airway management (AAM) is crucial during cardiopulmonary resuscitation, optimal timing remains unclear. This study examined the association between early AAM and clinical outcomes in adult OHCA patients. Methods: This retrospective study analyzed Korean nationwide OHCA registry data (August 2019–December 2022). Adult patients with emergency medical service-treated OHCA of presumed medical origin receiving AAM were included. Early AAM was defined as airway placement within 5 min of CPR initiation. Time-dependent propensity score matching controlled for selection bias and time-related confounding. Structural equation modeling examined associations between AAM timing and other prehospital interventions. Primary outcome was survival to hospital discharge with good neurological recovery (cerebral performance category 1–2). Results: Among 51,869 patients receiving AAM, 27,591 received early AAM and 24,278 received delayed AAM. After propensity score matching, 12,014 patients were included per group with balanced characteristics. Early AAM was associated with higher prehospital return of spontaneous circulation (11.8% vs. 10.5%; adjusted RR 1.21, 95% CI 1.12–1.29) and favorable neurological recovery (5.8% vs. 5.1%; adjusted RR 1.12, 95% CI 1.01–1.23). AAM timing correlated with timing of other critical interventions, including rhythm analysis and epinephrine administration. Conclusions: Early AAM within 5 min of CPR initiation was associated with improved neurological outcomes and increased prehospital ROSC in OHCA. Airway timing may indicate overall resuscitation quality, emphasizing the importance of coordinated, timely prehospital interventions. Full article

Background: Patients with out-of-hospital cardiac arrest (OHCA) are susceptible to hypoglycemia, which may worsen outcomes. Early identification of patients at risk is therefore essential. This study examined factors associated with hypoglycemia in OHCA survivors treated with targeted temperature management (TTM). Methods: We conducted an observational study of adults (≥18 years) with OHCA who received TTM between October 2015 and December 2024. Hypoglycemia was defined as blood glucose ≤ 70 mg/dL, assessed within 7 days of admission. The primary outcome was hypoglycemia occurrence. Results: Among 521 patients with OHCA, 69 (13.2%) developed hypoglycemia. Multivariable analysis identified body mass index (odds ratio [OR], 0.877; 95% confidence interval [CI], 0.808–0.953), N-terminal pro-B-type natriuretic peptide (NT-proBNP) > 2000 mg/dL (OR, 3.769; 95% CI, 2.060–6.898), and renal replacement therapy (OR, 3.429; 95% CI, 1.841–6.387) as independent factors associated with hypoglycemia. The area under the curve for the final adjusted model was 0.801 (95% CI, 0.764–0.835). Conclusions: In the OHCA patients who received TTM, body mass index, NT-proBNP > 2000, and renal replacement therapy were associated with hypoglycemia. Full article

The clinical pathway of a patient who experiences cardiac arrest and subsequently dies (with or without organ donation) is complex. It involves uncontrolled (u-) donation after circulatory death (DCD), controlled (c-) DCD, and donor after brain death (DBD). The present paper aims to summarize existing evidence on organ donation rates among out-of-hospital cardiac arrest (OHCA) patients, with a focus on these three donor categories (uDCD, DBD, and cDCD). Furthermore, the potential to expand each donor pathway in OHCA patients will be highlighted, based on available evidence. Among non-survivor OHCA patients, the prevalence of brain death (BD) is estimated to be low, though reported data are not uniform. The diagnosis of BD is made 3 to 6 days after return of spontaneous circulation. The implementation of uDCD is known to be quite challenging due to logistical, ethical, and resource issues. Its rationale is still well grounded, mainly considering two factors: (a) the high incidence of OHCA, such that uDCD donors can be considered an existing pool of potential donors; (b) the uDCD pathway shows feasibility both under organizational (i.e., only lung uDCD program) and clinical views (normothermic regional perfusion, ex vivo machine perfusion, and an appropriate donor–recipient match). Controlled DCDs are donors who died after a planned withdrawal of life-sustaining therapy (WLST). Data on the percentage of cDCD among OHCA patients is not uniform since the percentage of utilized cDCD has been estimated at around 10%. According to available evidence, each donor pathway in OHCA has the potential to be expanded, mainly by the identification of potential donors and the implementation of DCD programs. Full article

Background: Optic nerve sheath diameter (ONSD) and its ratio to eyeball transverse diameter (ETD; ONSD/ETD) are potential markers for elevated intracranial pressure in comatose survivors of out-of-hospital cardiac arrest (OHCA). However, their prognostic accuracy remains uncertain. We compared their predictive value via compted tomography (CT)and magnetic resonance imaging (MRI) before and after targeted temperature management (TTM) in OHCA survivors. Methods: This retrospective study included adult comatose OHCA survivors who underwent TTM and serial brain imaging. ONSD and ONSD/ETD ratios were measured on brain CT and MRI at two predefined time-points: within 6 h (pre-TTM) and at 72–96 h (post-TTM) after return of spontaneous circulation. Intra-rater reliability was assessed using intraclass correlation coefficients (ICC). Poor neurological outcome was defined as a Cerebral Performance Category score of 3–5 at 6 months. Prognostic performance was evaluated using area under the receiver operating characteristic curve (AUC). Results: Among 136 patients, 78 (57%) had poor neurological outcomes. Only ONSD (5.12 vs. 5.37 mm) and ONSD/ETD ratio (0.22 vs. 0.23) measured on post-TTM MRI were significantly higher in the poor outcome group. These results depicted modest predictive performance (AUC, 0.67 and 0.65, respectively), whereas all CT-based and early MRI measurements had AUC < 0.60. Intra-rater reliability for ONSD and ETD was higher on CT (ICC: up to 0.93) than on MRI (ICC: 0.73–0.80). Conclusions: Delayed MRI-based ONSD and ONSD/ETD showed statistically significant but modest prognostic value, with limited clinical applicability as a stand-alone tool. These findings underscore the relevance of measurement timing, supporting ONSD as an adjunctive, rather than definitive, tool in multimodal prognostication. Full article

Background: Out-of-hospital cardiac arrest (OHCA) survivors demonstrate wide variation in neurological outcomes due to hypoxic–ischemic brain injury. Early prognostic stratification in the emergency department is essential to inform clinical decisions. This study aimed to improve the revised Cardiac Arrest Syndrome for Therapeutic hypothermia (rCAST) score by incorporating additional clinical variables and to evaluate its ability to predict poor neurological outcomes. Methods: This multicenter observational study analyzed OHCA survivors treated with targeted temperature management (TTM) between October 2015 and December 2018 at 22 university-affiliated hospitals participating in the Korean Hypothermia Network prospective registry. The primary outcome was poor neurological status at one month, defined as a Cerebral Performance Category (CPC) score of 3–5. Independent predictors were identified using multivariable logistic regression and incorporated into a modified rCAST (mCAST) score. Results: Among 881 included patients, age > 65 years (odds ratio [OR], 13.87; 95% confidence interval [CI], 7.38–26.08) and absence of brainstem reflexes (OR, 2.31; 95% CI, 1.29–4.12) were identified as independent predictors and added to the mCAST score. The mCAST demonstrated higher prognostic accuracy than the original rCAST (area under the curve [AUC], 0.849 vs. 0.823; p < 0.001). In the high-severity group, the mCAST identified a higher poor outcome rate (95.1% vs. 90.9%) while reducing the proportion of patients in this group (20.7% vs. 31.3%). Conclusions: The mCAST score improves early prognostic accuracy during the immediate post-cardiac arrest period by incorporating age and brainstem reflexes and may offer refined risk stratification without compromising clinical feasibility. Full article

Background/Objectives: The association of scene time interval (STI) and field arrival to epinephrine administration time (FET) with outcomes in out-of-hospital cardiac arrest (OHCA) is unknown. The goal of this investigation is to assess the association of STI and FET with outcomes in OHCA. Methods: All adult OHCA cases with prehospital epinephrine administration in South Korea and Singapore were included. STI was divided into short and long stay based on the median value of each country. FET was categorized into early (<10 min) and late groups. We performed multivariable logistic regression for survival to discharge and good neurological recovery. Cases were grouped into short stay early epinephrine (SS-EE), short stay late epinephrine (SS-LE), long stay early epinephrine (LS-EE), and long stay late epinephrine (LS-LE) (reference). Interaction analysis with STI and FET for outcomes was conducted. Results: A total of 18,867 cases from South Korea and 4184 cases from Singapore were included. Adjusted odds ratio (AOR) for survival to discharge was 2.14 (95% CI: 1.18–2.25) in SS-EE, 1.15 (0.94–1.40) in SS-LE, and 1.82 (1.45–2.28) in LS-EE compared to LS-LE in South Korea with similar results for Singapore. SS-EE and LS-EE were also associated with good neurologic recovery. Interaction analysis showed that early epinephrine injection in short stay and long stay was associated with better outcomes. But short STI was not associated with better outcomes in early and late epinephrine groups. Conclusions: Early epinephrine administration was associated with higher survival to discharge irrespective of the scene time interval. Full article

Background/Objectives: Clinical observational studies often encounter missing data, which complicates association evaluation with reduced bias while accounting for confounders. This is particularly challenging in multi-national registries such as those for out-of-hospital cardiac arrest (OHCA), a time-sensitive medical emergency with low survival rates. While various methods for handling missing data exist, observational studies frequently rely on complete-case analysis, limiting representativeness and potentially introducing bias. Our objective was to evaluate the impact of various single imputation methods on association analysis with OHCA registries. Methods: Using a complete dataset (N = 13,274) from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry (1 January 2016–31 December 2020) as reference, we intentionally introduced missing values into selected variables via a Missing At Random (MAR) mechanism. We then compared statistical and machine learning (ML) single imputation methods to assess the association between bystander cardiopulmonary resuscitation (BCPR) and the issuance of a mobile app alert, adjusting for confounders. The impacts of complete-case analysis (CCA) and single imputation methods on conclusions in OHCA research were evaluated. Results: CCA was suboptimal for handling MAR data, resulting in more biased estimates and wider confidence intervals compared to single imputation methods. The missingness-indicator (MxI) method offered a trade-off between bias and ease of implementation. The K-Nearest Neighbours (KNN) method outperformed other imputation approaches, whereas missForest introduced bias under certain conditions. Conclusions: KNN and MxI are easy to use and better alternatives to CCA for reducing bias in observational studies. This study highlights the importance of selecting appropriate imputation methods to ensure reliable conclusions in OHCA research and has broader implications for other registries facing similar missing data challenges. Full article

Backgrounds: Most out-of-hospital cardiac arrest (OHCA) survivors are comatose due to hypoxic ischemic brain injury. Targeted temperature management (TTM) is the only evidence-based neuroprotective intervention for this condition; however, the optimal implementation of TTM has yet to be determined. The concept of high-quality TTM has been proposed to improve patient outcomes, but its clinical impact has not been thoroughly evaluated. This study investigates whether adherence to high-quality TTM is associated with improved neurological outcomes and survival among OHCA patients. Methods: This retrospective analysis used data from the Korean Hypothermia Network Prospective Registry 1.0, including 1060 adult OHCA patients treated with TTM at 33 °C between 2015 and 2018. High-quality TTM was defined as follows: temperature variability during maintenance within ±1.0 °C, maintenance duration ≥ 24 h, rewarming rate ≤ 0.5 °C/h, and post-TTM fever control (temperature < 38.5 °C). Patients were classified into high- and low-quality TTM groups. The primary outcomes were survival and neurological status (CPC ranging from 1 to 2 indicated a good outcome) 6 months after cardiac arrest (CA). Results: Of the 1060 patients, 491 (46.3%) received high-quality TTM. Compared with the low-quality TTM group, the high-quality TTM group had higher rates of survival (44.6% vs. 36.4%, p = 0.006). Multivariate analysis revealed that high-quality TTM was independently associated with survival (OR 1.802, 95% CI: 1.171–2.773) and good neurological outcomes (OR 1.748, 95% CI: 1.102–2.770). Conclusions: High-quality TTM is associated with improved survival and better neurological outcomes in OHCA patients. Standardizing TTM delivery on the basis of quality metrics may increase its effectiveness in clinical practice. Full article

Background/Objectives: Out-of-hospital cardiac arrest (OHCA) remains a major public health challenge, with survival rates significantly dependent on early defibrillation. In Bialystok, Poland, the bystander usage rate of automated external defibrillators (AEDs) is extremely low, and the current distribution of public-access AEDs may not support optimal response times. The aim of this study was to identify an effective AED placement strategy using spatial analysis. Methods: We retrospectively analyzed 49,649 emergency dispatch records from 2018 to 2019, identifying 787 patients with OHCA within Bialystok’s city limits. After excluding ineligible records, 766 cases were geolocated and subjected to cluster analysis using the K-means algorithm. The goal was to determine optimal AED locations based on the geographic distribution of OHCA cases in both public and residential settings. Results: AEDs were used in only 0.51% of all cases of OHCA. Most cardiac arrests occurred in private homes (80.05% of cases). Cluster analysis identified 18 to 36 optimal AED locations, revealing significant mismatches with the current AED network. Notably, grocery store chain “PSS Spolem” emerged as an ideal AED deployment partner due to alignment with identified high-incidence clusters. Conclusions: The current AED distribution in Bialystok is inadequate for an effective response to OHCA. Geographic cluster analysis can significantly improve placement strategies. Priority should be given to residential areas and commonly accessed sites. Enhanced public education, a national AED registry, and improved accessibility are essential for increasing AED use and survival rates. Full article

Background/Objectives: Out-of-hospital cardiac arrest (OHCA) is associated with high mortality, and outcomes may be influenced by underlying conditions such as cancer, hypertension (HTN), and diabetes mellitus (DM). This study aimed to evaluate whether HTN and DM modify the effects of post-resuscitation treatments—specifically targeted temperature management (TTM) and percutaneous coronary intervention (PCI)—on survival and neurological recovery in OHCA patients with a history of cancer. Methods: This retrospective cohort study analyzed data from the Korean national OHCA registry between January 2018 and December 2021. Adults aged ≥18 years with presumed cardiac-origin OHCA and a documented history of cancer—defined as any prior cancer diagnosis recorded in medical records regardless of remission status—were included. Multivariable logistic regression was used to examine associations between treatment and outcomes, and interaction effects were assessed using adjusted p-values to account for multiple testing. Results: Among the 124,916 EMS-assessed OHCA cases, 4115 patients met the inclusion criteria. TTM and PCI were both statistically associated with good neurological recovery (TTM: adjusted odds ratio [aOR], 1.69; 95% confidence interval [CI], 1.12–2.55; p < 0.05; PCI: aOR, 11.35; 95% CI, 7.98–16.14; p < 0.05). In interaction analyses, the benefit of TTM and PCI for achieving good neurological recovery was attenuated in patients with diabetes mellitus (DM; TTM: aOR, 0.59; 95% CI, 0.23–1.49; PCI: aOR, 4.94; 95% CI, 2.69–9.06) and hypertension (HTN; TTM: aOR, 0.94; 95% CI, 0.49–1.82; PCI: aOR, 7.47; 95% CI, 4.48–12.44), with adjusted p-values < 0.05 for all interactions. Conclusions: In OHCA patients with a history of cancer, TTM and PCI are associated with improved survival and neurological outcomes. However, the presence of comorbidities such as HTN and DM may attenuate these benefits. These findings support the need for individualized post-resuscitation care strategies that account for comorbid conditions. Full article