Søren Loumann Nielsen

Association of national initiatives to improve cardiac arrest management with rates of bystander intervention and patient survival after out-of-hospital cardiac arrest

IMPORTANCE Out-of-hospital cardiac arrest is a major health problem associated with poor outcomes. Early recognition and intervention are critical for patient survival. Bystander cardiopulmonary resuscitation (CPR) is one factor among many associated with improved survival. OBJECTIVE To examine temporal changes in bystander resuscitation attempts and survival during a 10-year period in which several national initiatives were taken to increase rates of bystander resuscitation and improve advanced care. DESIGN, SETTING, AND PARTICIPANTS Patients with out-of-hospital cardiac arrest for which resuscitation was attempted were identified between 2001 and 2010 in the nationwide Danish Cardiac Arrest Registry. Of 29,111 patients with cardiac arrest, we excluded those with presumed noncardiac cause of arrest (n = 7390) and those with cardiac arrests witnessed by emergency medical services personnel (n = 2253), leaving a study population of 19,468 patients. MAIN OUTCOMES AND MEASURES Temporal trends in bystander CPR, bystander defibrillation, 30-day survival, and 1-year survival. RESULTS The median age of patients was 72 years; 67.4% were men. Bystander CPR increased significantly during the study period, from 21.1% (95% CI, 18.8%-23.4%) in 2001 to 44.9% (95% CI, 42.6%-47.1%) in 2010 (P < .001), whereas use of defibrillation by bystanders remained low (1.1% [95% CI, 0.6%-1.9%] in 2001 to 2.2% [95% CI, 1.5%-2.9%] in 2010; P = .003). More patients achieved survival on hospital arrival (7.9% [95% CI, 6.4%-9.5%] in 2001 to 21.8% [95% CI, 19.8%-23.8%] in 2010; P < .001). Also, 30-day survival improved (3.5% [95% CI, 2.5%-4.5%] in 2001 to 10.8% [95% CI, 9.4%-12.2%] in 2010; P < .001), as did 1-year survival (2.9% [95% CI, 2.0%-3.9%] in 2001 to 10.2% [95% CI, 8.9%-11.6%] in 2010; P < .001). Despite a decrease in the incidence of out-of-hospital cardiac arrests during the study period (40.4 to 34.4 per 100,000 persons in 2001 and 2010, respectively; P = .002), the number of survivors per 100,000 persons increased significantly (P < .001). For the entire study period, bystander CPR was positively associated with 30-day survival, regardless of witnessed status (30-day survival for nonwitnessed cardiac arrest, 4.3% [95% CI, 3.4%-5.2%] with bystander CPR and 1.0% [95% CI, 0.8%-1.3%] without; odds ratio, 4.38 [95% CI, 3.17-6.06]). For witnessed arrest the corresponding values were 19.4% (95% CI, 18.1%-20.7%) vs 6.1% (95% CI, 5.4%-6.7%); odds ratio, 3.74 (95% CI, 3.26-4.28). CONCLUSIONS AND RELEVANCE In Denmark between 2001 and 2010, an increase in survival following out-of-hospital cardiac arrest was significantly associated with a concomitant increase in bystander CPR. Because of the co-occurrence of other related initiatives, a causal relationship remains uncertain.

Effect on Treatment Delay of Prehospital Teletransmission of 12-Lead Electrocardiogram to a Cardiologist for Immediate Triage and Direct Referral of Patients With ST-Segment Elevation Acute Myocardial Infarction to Primary Percutaneous Coronary Intervention

Prehospital electrocardiogram (ECG) transmission to hospitals was shown to reduce time to treatment in patients with acute myocardial infarction. However, new technologies allow transmission directly to a mobile unit so an attending physician can respond irrespective of presence within or outside the hospital. The primary study purpose was to determine whether delays could be decreased in an urban area by transmitting a prehospital 12-lead ECG directly to the attending cardiologists mobile telephone for rapid triage and transport to a primary percutaneous coronary intervention (PCI) center, bypassing local hospitals and emergency departments. A secondary purpose was to describe whether transport would be safe despite longer transport times. During a 2-year period, patients with acute nontraumatic chest pain had their prehospital ECG transmitted directly to a cardiologists mobile telephone. Time to treatment was compared with historic controls. After ECG evaluation, 168 patients (30%) were referred directly for PCI, and 146 of these (87%) underwent emergent catheterization. In referred patients, median time from 911 call to PCI was significantly shorter than in the control group (74 vs 127 minutes; p <0.001). Accordingly, door-to-PCI time was 63 minutes shorter for referred patients versus controls (34 vs 97 minutes; p <0.001). During transport, 7 patients (4%) experienced ventricular fibrillation; 3 patients (2%), ventricular tachycardia; and 1 patient (0.5%), pulseless electrical activity, including 2 deaths (1%) caused by treatment-resistant arrhythmia. In conclusion, transmission of a prehospital 12-lead ECG directly to the attending cardiologists mobile telephone decreased door-to-PCI time by >1 hour when patients were transported directly to PCI centers, bypassing local hospitals. Ambulance transport seems safe despite longer transport times.

Antidepressant Use and Risk of Out-of-Hospital Cardiac Arrest: A Nationwide Case–Time–Control Study

Treatment with some types of antidepressants has been associated with sudden cardiac death. It is unknown whether the increased risk is due to a class effect or related to specific antidepressants within drug classes. All patients in Denmark with an out‐of‐hospital cardiac arrest (OHCA) were identified (2001–2007). Association between treatment with specific antidepressants and OHCA was examined by conditional logistic regression in case–time–control models. We identified 19,110 patients with an OHCA; 2,913 (15.2%) were receiving antidepressant treatment at the time of OHCA, with citalopram being the most frequently used type of antidepressant (50.8%). Tricyclic antidepressants (TCAs; odds ratio (OR) = 1.69, confidence interval (CI): 1.14–2.50) and selective serotonin reuptake inhibitors (SSRIs; OR = 1.21, CI: 1.00–1.47) were both associated with comparable increases in risk of OHCA, whereas no association was found for serotonin–norepinephrine reuptake inhibitors/noradrenergic and specific serotonergic antidepressants (SNRIs/NaSSAs; OR = 1.06, CI: 0.81–1.39). The increased risks were primarily driven by: citalopram (OR = 1.29, CI: 1.02–1.63) and nortriptyline (OR = 5.14, CI: 2.17–12.2). An association between cardiac arrest and antidepressant use could be documented in both the SSRI and TCA classes of drugs.

Effect of antioxidant supplementation on insulin sensitivity in response to endurance exercise training.

While production of reactive oxygen and nitrogen species (RONS) is associated with some of the beneficial adaptations to regular physical exercise, it is not established whether RONS play a role in the improved insulin-stimulated glucose uptake in skeletal muscle obtained by endurance training. To assess the effect of antioxidant supplementation during endurance training on insulin-stimulated glucose uptake, 21 young healthy (age 29 ± 1 y, BMI 25 ± 3 kg/m(2)) men were randomly assigned to either an antioxidant [AO; 500 mg vitamin C and 400 IU vitamin E (α-tocopherol) daily] or a placebo (PL) group that both underwent a supervised intense endurance-training program 5 times/wk for 12 wk. A 3-h euglycemic-hyperinsulinemic clamp, a maximal oxygen consumption (Vo(2max)) and maximal power output (P(max)) test, and body composition measurements (fat mass, fat-free mass) were performed before and after the training. Muscle biopsies were obtained for determination of the concentration and activity of proteins regulating glucose metabolism. Although plasma levels of vitamin C (P < 0.05) and α-tocopherol (P < 0.05) increased markedly in the AO group, insulin-stimulated glucose uptake increased similarly in both the AO (17.2%, P < 0.05) and the PL (18.9%, P < 0.05) group in response to training. Vo(2max) and P(max) also increased similarly in both groups (time effect, P < 0.0001 for both) as well as protein content of GLUT4, hexokinase II, and total Akt (time effect, P ≤ 0.05 for all). Our results indicate that administration of antioxidants during strenuous endurance training has no effect on the training-induced increase in insulin sensitivity in healthy individuals.

Tertiary centres have improved survival compared to other hospitals in the Copenhagen area after out-of-hospital cardiac arrest ☆

AIMS Out-of-hospital cardiac arrest (OHCA) has been reported to carry very varying morbidity and mortality. However, it remains unclear whether this is caused by intrinsic factors of the OHCA or due to the level of in-hospital care. The aim of this study is to compare 30-day and long-term mortality after OHCA at tertiary heart centres and non-tertiary university hospitals. METHODS AND RESULTS Data from the Copenhagen OHCA registry from June 2002 through December 2010 included a total of 1218 consecutive patients treated by the same mobile emergency care unit (MECU) with either return of spontaneous circulation (ROSC) or on-going resuscitation (n=53) at hospital arrival. The MECU transported patients to the nearest hospital unless an ECG on scene suggested ST-segment elevation myocardial infarction, in which case patients were transported to the nearest tertiary centre for acute coronary angiography. Therefore, patients with ST-elevation myocardial infarction (n=198) were excluded from the analysis. 30-day mortality was 56% vs. 76% and long term (up to 8years) mortality was 78% vs. 94% for tertiary and non-tertiary hospitals, respectively, both p<0.001. Multivariate analysis showed that admission to a non-tertiary hospital was independently associated with increased risk of death (HR=1.32, 95% CI: 1.09-1.59, p=0.004). Exclusion of patients with on-going resuscitation at admission resulted in HR=1.34 (1.11-1.62), p=0.003. A matched pair propensity score analysis of 255 patients confirmed the results of the proportional hazard analysis (HR=1.35, 95% CI: 1.11-1.65 p=0.003). CONCLUSION Admission to tertiary centres is associated with lower mortality rates after OHCA compared with non-tertiary hospitals.

Out-of-hospital cardiac arrests in children and adolescents: Incidences, outcomes, and household socioeconomic status

BACKGROUND There is insufficient knowledge of out-of-hospital cardiac arrest (OHCA) in the very young. OBJECTIVES This nationwide study sought to examine age-stratified OHCA characteristics and the role of parental socioeconomic differences and its contribution to mortality in the young population. METHODS All OHCA patients in Denmark, ≤21 years of age, were identified from 2001 to 2010. The population was divided into infants (<1 year); pre-school children (1-5 years); school children (6-15 years); and high school adolescents/young adults (16-21 years). Multivariate logistic regression analyses were used to investigate associations between pre-hospital factors and study endpoints: return of spontaneous circulation and survival. RESULTS A total of 459 individuals were included. Overall incidence of OHCA was 3.3 per 100,000 inhabitants per year. The incidence rates for infants, pre-school children, school children and high school adolescents were 11.5, 3.5, 1.3 and 5.3 per 100,000 inhabitants. Overall bystander CPR rate was 48.8%, and for age groups: 55.4%, 41.2%, 44.9% and 63.0%, respectively. Overall 30-day survival rate was 8.1%, and for age groups: 1.4%, 4.5%, 16.1% and 9.3%, respectively. High parental education was associated with improved survival after OHCA (OR 3.48, CI 1.27-9.41). Significant crude difference in survival (OR 3.18, CI 1.22-8.34) between high household incomes vs. low household incomes was found. CONCLUSION OHCA incidences and survival rates varied significantly between age groups. High parental education was found to be associated with improved survival after OHCA.

Survival After Out-of-Hospital Cardiac Arrest in Relation to Age and Early Identification of Patients With Minimal Chance of Long-Term Survival

Background— Survival after out-of-hospital cardiac arrest has increased during the last decade in Denmark. We aimed to study the impact of age on changes in survival and whether it was possible to identify patients with minimal chance of 30-day survival. Methods and Results— Using data from the nationwide Danish Cardiac Arrest Registry (2001─2011), we identified 21 480 patients ≥18 years old with a presumed cardiac-caused out-of-hospital cardiac arrest for which resuscitation was attempted. Patients were divided into 3 preselected age-groups: working-age patients 18 to 65 years of age (33.7%), early senior patients 66 to 80 years of age (41.5%), and late senior patients >80 years of age (24.8%). Characteristics in working-age patients, early senior patients, and late senior patients were as follows: witnessed arrest in 53.8%, 51.1%, and 52.1%; bystander cardiopulmonary resuscitation in 44.7%, 30.3%, and 23.4%; and prehospital shock from a defibrillator in 54.7%, 45.0%, and 33.8% (all P<0.05). Between 2001 and 2011, return of spontaneous circulation on hospital arrival increased: working-age patients, from 12.1% to 34.6%; early senior patients, from 6.4% to 21.5%; and late senior patients, from 4.0% to 15.0% (all P<0.001). Furthermore, 30-day survival increased: working-age patients, 5.8% to 22.0% (P<0.001); and early senior patients, 2.7% to 8.4% (P<0.001), whereas late senior patients experienced only a minor increase (1.5% to 2.0%; P=0.01). Overall, 3 of 9499 patients achieved 30-day survival if they met 2 criteria: had not achieved return of spontaneous circulation on hospital arrival and had not received a prehospital shock from a defibrillator. Conclusions— All age groups experienced a large temporal increase in survival on hospital arrival, but the increase in 30-day survival was most prominent in the young. With the use of only 2 criteria, it was possible to identify patients with a minimal chance of 30-day survival.

Survival after out-of-hospital cardiac arrest in relation to sex: A nationwide registry-based study☆

AIM Crude survival has increased following an out-of-hospital cardiac arrest (OHCA). We aimed to study sex-related differences in patient characteristics and survival during a 10-year study period. METHODS Patients≥12 years old with OHCA of a presumed cardiac cause, and in whom resuscitation was attempted, were identified through the Danish Cardiac Arrest Registry 2001-2010. A total of 19,372 patients were included. RESULTS One-third were female, with a median age of 75 years (IQR 65-83). Compared to females, males were five years younger; and less likely to have severe comorbidities, e.g., chronic obstructive pulmonary disease (12.8% vs. 16.5%); but more likely to have arrest outside of the home (29.4% vs. 18.7%), receive bystander CPR (32.9% vs. 25.9%), and have a shockable rhythm (32.6% vs. 17.2%), all p<0.001. Thirty-day crude survival increased in males (3.0% in 2001 to 12.9% in 2010); and in females (4.8% in 2001 to 6.7% in 2010), p<0.001. Multivariable logistic regression analyses adjusted for patient characteristics including comorbidities, showed no survival difference between sexes in patients with a non-shockable rhythm (OR 1.00; CI 0.72-1.40), while female sex was positively associated with survival in patients with a shockable rhythm (OR 1.31; CI 1.07-1.59). Analyses were rhythm-stratified due to interaction between sex and heart rhythm; there was no interaction between sex and calendar-year. CONCLUSIONS Temporal increase in crude survival was more marked in males due to poorer prognostic characteristics in females with a lower proportion of shockable rhythm. In an adjusted model, female sex was positively associated with survival in patients with a shockable rhythm.

Feasibility and Safety of Prehospital Administration of Bivalirudin in Patients With ST-Elevation Myocardial Infarction

The selective thrombin inhibitor bivalirudin with a provisional glycoprotein IIb/IIIa inhibitor (GPI) has been shown to be comparable to heparin plus GPI in the rates of ischemic events but to significantly reduce the risk of bleeding complications in patients with acute coronary syndromes. The aim of this preliminary study was to describe the feasibility and safety of a switch from prehospital administration of unfractionated heparin to bivalirudin in ST-elevation acute myocardial infarction (STEMI) patients referred for primary percutaneous coronary intervention. Patients with STEMI treated with a 1-mg/kg bivalirudin bolus in the ambulance followed by infusion during angiography/primary percutaneous coronary intervention were compared with a STEMI control group (from the preceding year) treated with 10,000 U unfractionated heparin in the ambulance followed by in-hospital treatment with a GPI. A total of 102 patients (59%) receiving bivalirudin and 72 receiving heparin were followed during hospitalization. The baseline characteristics and prehospital treatment times were comparable between the 2 groups. The thrombolysis in myocardial infarction flow before and after primary percutaneous coronary intervention was similar. Stents were used significantly more often in the heparin-treated patients (90% versus 76%; p = 0.04), with bailout GPI for those receiving bivalirudin occurring in 30% compared with 83% of those receiving heparin (p <0.001). Significant bleeding complications were seen in <10% of all patients undergoing angiography with no difference between groups. Bivalirudin was easy to administer in the prehospital setting and did not affect the prehospital run times. In conclusion, the results suggest that prehospital bivalirudin administration is as safe and effective as heparin in the treatment of patients with STEMI. Prehospital administration seemed to reduce the need for GPI.

Referral of patients with ST-segment elevation acute myocardial infarction directly to the catheterization suite based on prehospital teletransmission of 12-lead electrocardiogram.

BACKGROUND Time from symptom onset to reperfusion is essential in patients with ST-segment elevation acute myocardial infarction. Prior studies have indicated that prehospital 12-lead electrocardiogram (ECG) transmission can reduce time to reperfusion. PURPOSE Determine 12-lead ECG transmission success rates, and time saved by referring patients directly to primary percutaneous coronary intervention (pPCI) bypassing local hospitals and emergency departments. METHODS Prehospital 12-lead ECG was recorded in patients with symptoms suggesting acute coronary syndrome during a 1-year pilot phase and transmitted to the attending cardiologists mobile phone. Transmission success rates were determined, and prehospital and hospital delays were recorded and compared to historic controls. RESULTS Transmission was attempted in 152 patients and was successful in 89%. Twenty-seven patients were referred directly for pPCI. Median hospital arrival to pPCI was 22 vs 94 minutes in the control group (P < .01). CONCLUSIONS Transmission of prehospital ECG is technically feasible and reduces time to pPCI in ST-segment elevation acute myocardial infarction patients.