Prediction of survival in out-of-hospital cardiac arrest: the updated Swedish cardiac arrest risk score (SCARS) model.

Aims: Out-of-hospital cardiac arrest (OHCA) is a major health concern worldwide. Although one-third of all patients achieve a return of spontaneous circulation and may undergo a difficult period in the intensive care unit, only 1 in 10 survive. This study aims to improve our previously developed machine learning model for early prognostication of survival in OHCA. Methods and results: We studied all cases registered in the Swedish Cardiopulmonary Resuscitation Registry during 2010 and 2020 (n = 55 615). We compared the predictive performance of extreme gradient boosting (XGB), light gradient boosting machine (LightGBM), logistic regression, CatBoost, random forest, and TabNet. For each framework, we developed models that optimized (i) a weighted F1 score to penalize models that yielded more false negatives and (ii) a precision-recall area under the curve (PR AUC). LightGBM assigned higher importance values to a larger set of variables, while XGB made predictions using fewer predictors. The area under the curve receiver operating characteristic (AUC ROC) scores for LightGBM were 0.958 (optimized for weighted F1) and 0.961 (optimized for a PR AUC), while for XGB, the scores were 0.958 and 0.960, respectively. The calibration plots showed a subtle underestimation of survival for LightGBM, contrasting with a mild overestimation for XGB models. In the crucial range of 0-10% likelihood of survival, the XGB model, optimized with the PR AUC, emerged as a clinically safe model. Conclusion: We improved our previous prediction model by creating a parsimonious model with an AUC ROC at 0.96, with excellent calibration and no apparent risk of underestimating survival in the critical probability range (0-10%). The model is available at www.gocares.se.

Progressive changes in pulmonary gas exchange during invasive respiratory support for COVID-19 associated acute respiratory failure: A retrospective study of the association with 90-day mortality.

BACKGROUND: Ratio of arterial pressure of oxygen and fraction of inspired oxygen (P/F ratio) together with the fractional dead space (Vd/Vt) provides a global assessment of pulmonary gas exchange. The aim of this study was to assess the potential value of these variables to prognosticate 90-day survival in patients with COVID-19 associated ARDS admitted to the Intensive Care Unit (ICU) for invasive ventilatory support. METHODS: In this single-center observational, retrospective study, P/F ratios and Vd/Vt were assessed up to 4 weeks after ICU-admission. Measurements from the first 2 weeks were used to evaluate the predictive value of P/F ratio and Vd/Vt for 90-day mortality and reported by the adjusted hazard ratio (HR) and 95% confidence intervals [95%CI] by Cox proportional hazard regression. RESULTS: Almost 20,000 blood gases in 130 patients were analyzed. The overall 90-day mortality was 30% and using the data from the first ICU week, the HR was 0.85 [0.77-0.94] for every 10 mmHg increase in P/F ratio and 1.61 [1.20-2.16] for every 0.1 increase in Vd/Vt. In the second week, the HR for 90-day mortality was 0.82 [0.75-0.89] for every 10 mmHg increase in P/F ratio and 1.97 [1.42-2.73] for every 0.1 increase in Vd/Vt. CONCLUSION: The progressive changes in P/F ratio and Vd/Vt in the first 2 weeks of invasive ventilatory support for COVID-19 ARDS were significant predictors for 90-day mortality.

No obesity paradox in out-of-hospital cardiac arrest: Data from the Swedish registry of cardiopulmonary resuscitation.

Background: Although an "obesity paradox", which states an increased chance of survival for patients with obesity after myocardial infarction has been proposed, it is less clear whether this phenomenon even exists in patients suffering out-of-hospital cardiac arrest (OHCA) and if diabetes, which is often associated with obesity, implies an additional risk. Objective: To investigate if and how obesity, with or without diabetes, affects the survival of patients with OHCA. Methods: This study included 55,483 patients with OHCA reported to the Swedish Registry of Cardiopulmonary Resuscitation between 2010 and 2020. Patients were classified in five groups: obesity only (Ob), type 1 diabetes only (T1D), type 2 diabetes only (T2D), obesity and any diabetes (ObD), or belonging to the group other (OTH). Patient characteristics and outcomes were studied using descriptive statistics, logistic, and Cox proportional regression. Results: Obesity only was found in 2.7% of the study cohort, while 3.2% had obesity and any type of diabetes. Ob patients were significantly younger than all other patients (p ≤ 0.001); the 30 day-survival was 9.6% in Ob, and 10.6%, 7.3%, 6.9%, and 12.7% in T1D, T2D, ObD, and OTH, respectively, with OR (95% CI) of 0.69 (0.57-0.82), 0.78 (0.56-1.05), 0.65 (0.59-0.71), and 0.55 (0.45-0.66) for Ob, T1D, T2D, and ObD, respectively (reference group OTH). No time-related trends in 30-days survival were found. Conclusion: Obesity was present in 6% of the population and was associated with younger age and a 30% reduction in survival; a combination of obesity and diabetes further reduced the survival rate.

Temporal variation in survival following in-hospital cardiac arrest in Sweden.

BACKGROUND: The aim of the study was to investigate what characterizes IHCAs that take place during the "day" (Monday-Friday 7 am-3 pm), "evening" (Monday-Friday 3 pm-9 pm) and "night" (Monday-Friday 9 pm-7 am and Saturday-Sunday 12 am- 11.59 pm). METHODS: We used the Swedish Registry for CPR (SRCR) to study 26,595 patients from January 1, 2008 to December 31, 2019. Adult patients ≥18 years with a IHCA where resuscitation was initiated were included. Uni- and multivariable logistic regression was used to investigate associations between temporal factors and survival to 30 days. RESULTS: 30-day survival and Return of Spontaneous Circulation (ROSC) was 36.8% and 67.9% following CA during the day and decreased during the evening (32.0% and 66.3%) and night (26.2% and 60.2%) (p < 0.001 and p = 0.028). When comparing the survival rates between the day and the night, survival decreased more (change in relative survival rates) in small (<99 beds) compared to large (<400) hospitals (35.9% vs 25%), in non-academic vs academic hospitals (33.5% vs 22%) and on non-Electro Cardiogram (ECG)-monitored wards vs ECG-monitored wards (46.2% vs 20.9%) (p < 0.001 for all). IHCAs that took place during the day (adjusted Odds Ratio (aOR) 1.47 95% CI 1.35-1.60), in academic hospitals (aOR 1.14 95% CI 1.02-1.27) and in large (>400 beds) hospitals (aOR 1.31 95% CI 1.10-1.55) were independently associated with an increased chance of survival. CONCLUSIONS: Patients suffering an IHCA have an increased chance of survival during the day vs the evening vs night, and the difference in survival is even more pronounced when cared for at smaller, non-academic hospitals, general wards and wards without ECG-monitoring capacity.

Predicting survival and neurological outcome in out-of-hospital cardiac arrest using machine learning: the SCARS model.

BACKGROUND: A prediction model that estimates survival and neurological outcome in out-of-hospital cardiac arrest patients has the potential to improve clinical management in emergency rooms. METHODS: We used the Swedish Registry for Cardiopulmonary Resuscitation to study all out-of-hospital cardiac arrest (OHCA) cases in Sweden from 2010 to 2020. We had 393 candidate predictors describing the circumstances at cardiac arrest, critical time intervals, patient demographics, initial presentation, spatiotemporal data, socioeconomic status, medications, and comorbidities before arrest. To develop, evaluate and test an array of prediction models, we created stratified (on the outcome measure) random samples of our study population. We created a training set (60% of data), evaluation set (20% of data), and test set (20% of data). We assessed the 30-day survival and cerebral performance category (CPC) score at discharge using several machine learning frameworks with hyperparameter tuning. Parsimonious models with the top 1 to 20 strongest predictors were tested. We calibrated the decision threshold to assess the cut-off yielding 95% sensitivity for survival. The final model was deployed as a web application. FINDINGS: We included 55,615 cases of OHCA. Initial presentation, prehospital interventions, and critical time intervals variables were the most important. At a sensitivity of 95%, specificity was 89%, positive predictive value 52%, and negative predictive value 99% in test data to predict 30-day survival. The area under the receiver characteristic curve was 0.97 in test data using all 393 predictors or only the ten most important predictors. The final model showed excellent calibration. The web application allowed for near-instantaneous survival calculations. INTERPRETATION: Thirty-day survival and neurological outcome in OHCA can rapidly and reliably be estimated during ongoing cardiopulmonary resuscitation in the emergency room using a machine learning model incorporating widely available variables. FUNDING: Swedish Research Council (2019-02019); Swedish state under the agreement between the Swedish government, and the county councils (ALFGBG-971482); The Wallenberg Centre for Molecular and Translational Medicine.

Cardiopulmonary Resuscitation and Vital Function Failure Refresher Training Strengthen Healthcare Professionals' Self-Assessed Abilities: A Questionnaire-Based Pilot Study.

Refresher training in cardiopulmonary resuscitation and recognition of patients with failure in vital functions are often completed on separate occasions. In this study, 63 healthcare professionals participated in a pilot course and self-assessed their abilities before and after the course. Combining training scenarios with different diagnoses of patient cases provided a real-life learning environment. The training strengthened the perceived ability of healthcare professionals to respond to an acute situation of a patient with failure of vital functions.

Factors associated with treatment limitations in two Swedish intensive care units: Prevalence and patient involvement.

The aim was to study the prevalence, documentation, and patient involvement in treatment limitations (TLs) in two Swedish intensive care units (ICUs). All patients admitted to the ICUs of two Swedish regional hospitals in 2019 were screened for inclusion. Exclusion criteria included postanesthesia care <24 h. Patients were identified using the Swedish Intensive Care Registry (SIR) and data were extracted from SIR and hospital charts. Uni- and multivariable logistic analysis was performed to investigate associations with the presence of TLs. A total of 3090 patients were admitted to the two ICUs in 2019. After exclusion, 1019 patients were included in the study. 45.5% were women and the mean age was 62.9 years. 26.5% of the patients had one or several TLs. Age (OR 1.04 per one year increase 95% confidence interval (CI) 1.02-1.05), SAPS3-score (OR 1.08 per one unit increase 95% CI 1.06-1.09) and ICU length of stay (OR 1.11 per one day increase 95% CI 1.05-1.17) were independently associated with an increased likelihood of receiving a TL. 17% of the patients were involved in the decision-making process and in >30% of cases neither the patient nor next-of-kin were informed. Women were to a larger extent involved in the decision process than men (24.5 vs. 12.5% p < .05). When the intensivist documented why a TL was established, patient autonomy was four times more commonly stated as the motivation for the TL among women compared to men (15.5% vs. 3.8% p < .05). TLs were common in two Swedish ICUs but a substantial number of patients and next-of-kin were not involved in the decision-making process or informed of the decision. Women were more often than men engaged in the decision to establish a TL.

Predicting recurrent cardiac arrest in individuals surviving Out-of-Hospital cardiac arrest.

BACKGROUND: Despite improvements in short-term survival for Out-of-Hospital Cardiac Arrest (OHCA) in the past two decades, long-term survival is still not well studied. Furthermore, the contribution of different variables on long-term survival have not been fully investigated. AIM: Examine the 1-year prognosis of patients discharged from hospital after an OHCA. Furthermore, identify factors predicting re-arrest and/or death during 1-year follow-up. METHODS: All patients 18 years or older surviving an OHCA and discharged from the hospital were identified from the Swedish Register for Cardiopulmonary Resuscitation (SRCR). Data on diagnoses, medications and socioeconomic factors was gathered from other Swedish registers. A machine learning model was constructed with 886 variables and evaluated for its predictive capabilities. Variable importance was gathered from the model and new models with the most important variables were created. RESULTS: Out of the 5098 patients included, 902 (∼18%) suffered a recurrent cardiac arrest or death within a year. For the outcome death or re-arrest within 1 year from discharge the model achieved an ROC (receiver operating characteristics) AUC (area under the curve) of 0.73. A model with the 15 most important variables achieved an AUC of 0.69. CONCLUSIONS: Survivors of an OHCA have a high risk of suffering a re-arrest or death within 1 year from hospital discharge. A machine learning model with 15 different variables, among which age, socioeconomic factors and neurofunctional status at hospital discharge, achieved almost the same predictive capabilities with reasonable precision as the full model with 886 variables.

Characteristics, survival and neurological outcome in out-of-hospital cardiac arrest: A nationwide study of 56,203 cases with emphasis on cardiovascular comorbidities.

Background: We studied clinical characteristics, survival and neurological outcomes in patients with pre-existing cardiovascular (CV) conditions who experienced an out-of-hospital cardiac arrest (OHCA). Methods: We studied all cases of OHCA in the Swedish Registry for Cardiopulmonary Resuscitation (2010-2020). Patients were grouped according to the following pre-existing CV conditions prior: hypertension (HT), heart failure (HF) with HT, HF with ischemic heart disease (IHD), HF without HT or IHD, IHD, myocardial infarction (MI) and diabetes mellitus (DM), with groups being mutually exclusive. We studied 30-day survival and neurological outcomes using logistic and Cox regression. Results: A total of 56,203 patients were included. The lowest rates of shockable rhythm occurred in cases with HT (19%), HF and HT (18%) and DM (18%). Median time to OHCA from diagnosis of HT was 2.0 years in cases aged 0-40 years at diagnosis of HT, 4.4 years in those aged 41-60 at diagnosis, 5.0 years in those aged 61-70 years, 5.6 years in those aged 71-80 years and 6.0 years in those aged 81 years or older. The lowest survival was noted for patients with HF and HT. Age and sex adjusted OR for CPC score 1 did not differ in any group. Conclusion: The combination of HT and HF has the lowest survival of all cardiovascular comorbidities. Early onset of hypertension is a predictor for early cardiac arrest.

Cardiac arrest in COVID-19: characteristics and outcomes of in- and out-of-hospital cardiac arrest. A report from the Swedish Registry for Cardiopulmonary Resuscitation.

AIM: To study the characteristics and outcome among cardiac arrest cases with COVID-19 and differences between the pre-pandemic and the pandemic period in out-of-hospital cardiac arrest (OHCA) and in-hospital cardiac arrest (IHCA). METHOD AND RESULTS: We included all patients reported to the Swedish Registry for Cardiopulmonary Resuscitation from 1 January to 20 July 2020. We defined 16 March 2020 as the start of the pandemic. We assessed overall and 30-day mortality using Cox regression and logistic regression, respectively. We studied 1946 cases of OHCA and 1080 cases of IHCA during the entire period. During the pandemic, 88 (10.0%) of OHCAs and 72 (16.1%) of IHCAs had ongoing COVID-19. With regards to OHCA during the pandemic, the odds ratio for 30-day mortality in COVID-19-positive cases, compared with COVID-19-negative cases, was 3.40 [95% confidence interval (CI) 1.31-11.64]; the corresponding hazard ratio was 1.45 (95% CI 1.13-1.85). Adjusted 30-day survival was 4.7% for patients with COVID-19, 9.8% for patients without COVID-19, and 7.6% in the pre-pandemic period. With regards to IHCA during the pandemic, the odds ratio for COVID-19-positive cases, compared with COVID-19-negative cases, was 2.27 (95% CI 1.27-4.24); the corresponding hazard ratio was 1.48 (95% CI 1.09-2.01). Adjusted 30-day survival was 23.1% in COVID-19-positive cases, 39.5% in patients without COVID-19, and 36.4% in the pre-pandemic period. CONCLUSION: During the pandemic phase, COVID-19 was involved in at least 10% of all OHCAs and 16% of IHCAs, and, among COVID-19 cases, 30-day mortality was increased 3.4-fold in OHCA and 2.3-fold in IHCA.

Adherence to guidelines is associated with improved survival following in-hospital cardiac arrest.

BACKGROUND: Most resuscitation guidelines have recommendations regarding maximum delay times from collapse to calling for the rescue team and initiation of treatment following cardiac arrest. The aim of the study was to investigate the association between adherence to guidelines for cardiopulmonary resuscitation (CPR) after in-hospital cardiac arrest (IHCA) and survival with a focus on delay to treatment. METHODS: We used the Swedish Registry for CPR to study 3212 patients with a shockable rhythm and 9113 patients with non-shockable rhythm from January 1, 2008 to December 31, 2017. Adult patients older than or equal to 18 years with a witnessed IHCA where resuscitation was initiated were included. We assessed trends in adherence to guidelines and their associations with 30-day survival and neurological function. Adherence to guidelines was defined as follows: time from collapse to calling for the rescue team and CPR within 1 min for non-shockable rhythms. For shockable rhythms, adherence was defined as the time from collapse to calling for the rescue team and CPR within 1 min and defibrillation within 3 min. RESULTS: In patients with a shockable rhythm, the 30-day survival for those treated according to guidelines was 66.1%, as compared to 46.5% among those not treated according to guidelines on one or more parameters, adjusted odds ratio 1.84 (95% CI 1.52-2.22). Among patients with a non-shockable rhythm the 30-day survival for those treated according to guidelines was 22.8%, as compared to 16.0% among those not treated according to guidelines on one or more parameters, adjusted odds ratio 1.43 (95% CI 1.24-1.65). Neurological function (cerebral performance category 1-2) among survivors was better among patients treated in accordance with guidelines for both shockable (95.7% vs 91.1%, <0.001) and non-shockable rhythms (91.0% vs 85.5%, p < 0.008). Adherence to the Swedish guidelines for CPR increased slightly 2008-2017. CONCLUSIONS: Adherence to guidelines was associated with increased probability of survival and improved neurological function in patients with a shockable and non-shockable rhythm, respectively. Increased adherence to guidelines could increase cardiac arrest survival.

[Thyroid storm and diabetic ketoacidosis (DKA) in a previously healthy male - a significant differential diagnostic challenge]. / Tyreotoxisk kris maskerades av ketoacidos.

Thyroid storm is a potentially lethal condition sometimes seen in cases of untreated thyrotoxicosis. Hypermetabolism, fever, and tachycardia are typical symptoms of the increased thyroid hormone activity. Thyroid storm is often triggered by infection, trauma or recent surgery and rarely by other causes. We present a case of thyroid storm and diabetic ketoacidosis (DKA) in a previously healthy male. After extensive lab testing, the patient was found to have both an undiagnosed type 1 diabetes and Graves disease. This combination of underlying conditions and the combined presentation of thyroid storm and DKA pose a significant differential diagnostic challenge, and this case report reminds us to think broadly when presented with an atypical case.

Factors of importance to 30-day survival after in-hospital cardiac arrest in Sweden - A population-based register study of more than 18,000 cases.

BACKGROUND AND OBJECTIVE: In-hospital cardiac arrest (IHCA) constitutes a major contributor to cardiovascular mortality. The aim of the present study was to investigate factors of importance to 30-day survival after IHCA in Sweden. METHODS: A retrospective register study based on the Swedish Register of Cardiopulmonary Resuscitation (SRCPR) 2006-2015. Sixty-six of 73 hospitals in Sweden participated. The inclusion criterion was a confirmed cardiac arrest in which resuscitation was attempted among patients aged >18years. RESULTS: In all, 18,069 patients were included, 39% of whom were women. The median age was 75years. Thirty-day survival was 28.3%, 93% with a CPC score of 1-2. One-year survival was 25.0%. Overall IHCA incidence in Sweden was 1.7 per 1000 hospital admissions. Several factors were found to be associated with 30-day survival in a multivariable analysis. They included cardiac arrest (CA) at working days during the daytime (08-20) compared with weekends and night-time (20-08) (OR 1.51 95% CI 1.39-1.64), monitored CA (OR 2.18 95% CI 1.99-2.38), witnessed CA (OR 2.87 95% CI 2.48-3.32) and if the first recorded rhythm was ventricular fibrillation/tachycardia, especially in combination with myocardial ischemia/infarction as the assumed aetiology of the CA (OR for interaction 4.40 95% CI 3.54-5.46). CONCLUSION: 30-day survival after IHCA is associated with the time of the event, the aetiology of the CA and the degree of monitoring and this should influence decisions regarding the appropriate level of monitoring and care.

Campylobacter jejuni-associated perimyocarditis: two case reports and review of the literature.

BACKGROUND: Campylobacter spp. are among the most common bacterial causes of gastroenteritis world-wide and mostly follow a benign course. We report two cases of Campylobacter jejuni-associated perimyocarditis, the first two simultaneous cases published to date and the third and fourth cases over all in Sweden, and a review of the literature. CASE PRESENTATION: A previously healthy 24-yo male (A) presented at the Emergency Department(ED) with recent onset of chest pain and a 3-day history of abdominal pain, fever and diarrhoea. The symptoms began within a few hours of returning from a tourist visit to a central European capital. Vital signs were stable, the Electrocardiogram(ECG) showed generalized ST-elevation, laboratory testing showed increased levels of C-reactive protein(CRP) and high-sensitive Troponin T(hsTnT). Transthoracic echocardiogram (TTE) was normal, stool cultures were positive for C Jejuni and blood cultures were negative. Two days after patient A was admitted to the ED his travel companion (B), also a previously healthy male (23-yo), presented at the same ED with almost identical symptoms: chest pain precipitated by a few days of abdominal pain, fever and diarrhoea. Patient B declared that he and patient A had ingested chicken prior to returning from their tourist trip. Laboratory tests showed elevated CRP and hsTnT but the ECG and TTE were normal. In both cases, the diagnosis of C jejuni-associated perimyocarditis was set based on the typical presentation and positive stool cultures with identical strains. Both patients were given antibiotics, rapidly improved and were fully recovered at 6-week follow up. CONCLUSION: Perimyocarditis is a rare complication of C jejuni infections but should not be overlooked considering the risk of heart failure. With treatment, the prognosis of full recovery is good but several questions remain to be answered regarding the pathophysiology and the male preponderance of the condition.