Prospective Countywide Surveillance and Autopsy Characterization of Sudden Cardiac Death: POST SCD Study.

BACKGROUND: Studies of out-of-hospital cardiac arrest and sudden cardiac death (SCD) use emergency medical services records, death certificates, or definitions that infer cause of death; thus, the true incidence of SCD is unknown. Over 90% of SCDs occur out-of-hospital; nonforensic autopsies are rarely performed, and therefore causes of death are presumed. We conducted a medical examiner-based investigation to determine the precise incidence and autopsy-defined causes of all SCDs in an entire metropolitan area. We hypothesized that postmortem investigation would identify actual sudden arrhythmic deaths among presumed SCDs. METHODS: Between February 1, 2011, and March 1, 2014, we prospectively identified all incident deaths attributed to out-of-hospital cardiac arrest (emergency medical services primary impression, cardiac arrest) between 18 to 90 years of age in San Francisco County for autopsy, toxicology, and histology via medical examiner surveillance of consecutive out-of-hospital deaths, all reported by law. We obtained comprehensive records to determine whether out-of-hospital cardiac arrest deaths met World Health Organization (WHO) criteria for SCD. We reviewed death certificates filed quarterly for missed SCDs. Autopsy-defined sudden arrhythmic deaths had no extracardiac cause of death or acute heart failure. A multidisciplinary committee adjudicated final cause. RESULTS: All 20 440 deaths were reviewed; 12 671 were unattended and reported to the medical examiner. From these, we identified 912 out-of-hospital cardiac arrest deaths; 541 (59%) met WHO SCD criteria (mean 62.8 years, 69% male) and 525 (97%) were autopsied. Eighty-nine additional WHO-defined SCDs occurred within 3 weeks of active medical care with the death certificate signed by the attending physician, ineligible for autopsy but included in the countywide WHO-defined SCD incidence of 29.6/100 000 person-years, highest in black men (P<0.0001). Of 525 WHO-defined SCDs, 301 (57%) had no cardiac history. Leading causes of death were coronary disease (32%), occult overdose (13.5%), cardiomyopathy (10%), cardiac hypertrophy (8%), and neurological (5.5%). Autopsy-defined sudden arrhythmic deaths were 55.8% (293/525) of overall, 65% (78/120) of witnessed, and 53% (215/405) of unwitnessed WHO-defined SCDs (P=0.024); 286 of 293 (98%) had structural cardiac disease. CONCLUSIONS: Forty percent of deaths attributed to stated cardiac arrest were not sudden or unexpected, and nearly half of presumed SCDs were not arrhythmic. These findings have implications for the accuracy of SCDs as defined by WHO criteria or emergency medical services records in aggregate mortality data, clinical trials, and cohort studies.

EMS Can Safely Transport Intoxicated Patients to a Sobering Center as an Alternate Destination.

STUDY OBJECTIVE: We evaluate a sobering center as an alternate destination for acute intoxication. Our aims are to count patient visits that originated from emergency medical services (EMS) or the emergency department (ED) that then result in a secondary transfer from the sobering center to the ED, and to describe and categorize the clinical reasons for transfer to the ED. METHODS: The San Francisco Sobering Center, a continuously nurse-staffed facility operating since 2003, provides short-term (6- to 8-hour) care for adults with acute alcohol intoxication. Paramedics use a county EMS protocol to triage low-risk intoxicated patients to the sobering center. A case review was performed on all visitors during 3 years who were secondarily transferred from the sobering center. Reason for transfer was categorized by clinical indication. RESULTS: From July 2013 to June 2016, 11,596 visits (from 3,268 unduplicated adults) were documented. Of these, 4,045 (35%) were referred by EMS and 1,348 (12%) were referred from the ED. Other referring parties included the mobile van service, police, homeless service provider, self-referral, and others. Of the total visitors, 506 (4.4%; 95% confidence interval 4.0% to 4.8%) were secondarily transferred to an ED; 151 were referred by EMS and 62 by the ED. Clinical indications for ED transfer included pulse greater than 100 beats/min (26%), alcohol withdrawal (19%), pain (excluding chest pain) (19%), altered mental status (13%), and emesis (13%). Most clients had more than one clinical indication for transfer (median 2; range 1 to 5). CONCLUSION: The San Francisco Sobering Center is an appropriate, safe EMS destination for patients with acute alcohol intoxication.

Community-Based Response to Fentanyl Overdose Outbreak, San Francisco, 2015.

This report documents a successful intervention by a community-based naloxone distribution program in San Francisco. The program and its partner organizations, working with participants who use drugs, first identified the appearance of illicitly made fentanyl and increased outreach and naloxone distribution. Distribution of naloxone and reported use of naloxone to reverse opioid-involved overdoses increased significantly while the number of opioid-involved and fentanyl-involved overdose deaths did not. Community-based programs that provide training and naloxone to people who use drugs can serve as an early warning system for overdose risk and adaptively respond to the rapidly changing overdose risk environment.

EMS-STARS: Emergency Medical Services "Superuser" Transport Associations: An Adult Retrospective Study.

Abstract Objective. Emergency medical services (EMS) "superusers" -those who use EMS services at extremely high rates -have not been well characterized. Recent interest in the small group of individuals who account for a disproportionate share of health-care expenditures has led to research on frequent users of emergency departments and other health services, but little research has been done regarding those who use EMS services. To inform policy and intervention implementation, we undertook a descriptive analysis of EMS superusers in a large urban community. In this paper we compare EMS superusers to low, moderate, and high users to characterize factors contributing to EMS use. We also estimate the financial impact of EMS superusers. Methods. We conducted a retrospective cross-sectional study based on 1 year of data from an urban EMS system. Data for all EMS encounters with patients age ≥18 years were extracted from electronic records generated on scene by paramedics. We identified demographic and clinical variables associated with levels of EMS use. EMS users were characterized by the annual number of EMS encounters: low (1), moderate (2-4), high (5-14), and superusers (≥15). In addition, we performed a financial analysis using San Francisco Fire Department (SFFD) 2009 charge and reimbursement data. Results. A total of 31,462 adults generated 43,559 EMS ambulance encounters, which resulted in 39,107 transports (a 90% transport rate). Encounters for general medical reasons were common among moderate and high users and less frequent among superusers and low users, while alcohol use was exponentially correlated with encounter frequency. Superusers were significantly younger than moderate EMS users, and more likely to be male. The superuser group created a significantly higher financial burden/person than any other group, comprising 0.3% of the study population, but over 6% of annual EMS charges and reimbursements. Conclusions. In this retrospective study, adult EMS "superusers" emerged as a distinct, predominantly male population and their EMS encounters were associated with alcohol use. Continued analysis of this unique, high-cost, and frequently transported population will likely illuminate specific intervention strategies.

Does emergency medical dispatch priority predict delphi process-derived levels of prehospital intervention?

OBJECTIVE: The Medical Priority Dispatch System (MPDS) is an emergency medical dispatch system widely used to prioritize 9-1-1 calls and optimize resource allocation. This study evaluates whether the assigned priority predicts a Delphi process-derived level of prehospital intervention in each emergency medical dispatch category. METHODS: All patients given a MPDS priority in a suburban California county from 2004-2006 were included. A Delphi process of emergency medical services (EMS) professionals in another system developed the following categories of prehospital treatment representing increasing acuity, which were adapted for this study: advanced life support (ALS) intervention, ALS-Stat, and ALS-Critical. The sensitivities and specificities of MPDS priority for level of prehospital intervention were determined for each MPDS category. Likelihood ratios of low and high priority dispatch codes for the level of prehospital intervention also were calculated for each MPDS category. RESULTS: A total of 65,268 patients met inclusion criteria, representing 61% of EMS calls during the study period. The overall sensitivities of high-priority dispatch codes for ALS, ALS-Stat, and ALS-Critical interventions were 83% (95% confidence interval 83-84%), 83% (82-84%), and 94% (92-96%). Overall specificities were: ALS, 32% (31-32%); ALS-Stat, 31% (30-31%); and ALS-Critical 28% (28-29%). Compared to calls assigned to a low priority, calls with high-priority dispatch codes were more likely to receive ALS interventions by 22%, ALS-Stat by 20%, and ALS-Critical by 32%. A low priority dispatch code decreased the likelihood of ALS interventions by 48%, ALS-Stat by 45%, and ALS-Critical by 80%. Among high-priority dispatch codes, the rates of interventions were: ALS 26%, ALS-Stat 22%, and ALS-Critical 1.5%, all of which were significantly greater than low-priority calls (p<0.05) [ALS 13%, ALS-Stat 11%, and ALS-Critical 0.2%]. Major MPDS were categories with high sensitivities (>95%) for ALS interventions included breathing problems, cardiac or respiratory arrest/death, chest pain, stroke, and unconscious/fainting; these categories had an average specificity of 3%. Medical Priority Dispatch System categories such as back pain, unknown problem, and traumatic injury had sensitivities for ALS interventions<15%. CONCLUSIONS: The MPDS is moderately sensitive for the Delphi process derived ALS, ALS-Stat, and ALS-Critical intervention levels, but nonspecific. A low MPDS priority is predictive of no prehospital intervention. A high priority, however, is of little predictive value for ALS, ALS-Stat, or ALS-Critical interventions.

Death after emergency department visits for syncope: how common and can it be predicted?

STUDY OBJECTIVE: Syncope is a common condition that is usually benign but occasionally associated with death. This study evaluates the incidence of death after an emergency department (ED) visit for syncope and whether these deaths can be predicted. METHODS: A prospective cohort study was conducted during a 45-month period. All patients were followed up 1-and-a-half years after their initial ED visit to determine whether they had died. Death certificates were independently reviewed by 2 physicians for the cause and date of death to determine whether the death was possibly related to the initial visit for syncope. Sensitivity and specificity of risk factors (defined by the San Francisco Syncope Rule) or age greater than 65 years was calculated for all-cause mortality and mortality thought possibly related to syncope. RESULTS: There were 1418 consecutive patients with syncope during the study period, representing 1.2% of all ED visits. The all-cause death rate was 1.4% at 30 days, 4.3% at 6 months, and 7.6% at 1 year. It was believed that the death rates from causes possibly related to syncope were 2.3% and 3.8% at 6 months and 1 year. Of the 112 deaths at 1 year, 37% were cardiac related. At 6 months, the risk factors had a sensitivity of 89% (95% confidence interval [CI] 79% to 95%) and specificity of 53% (95% CI 52% to 53%) for all-cause mortality and sensitivity of 100% (95% CI 90% to 100%) and specificity 52% (95% CI 52% to 53%) for predicting deaths likely or possibly related to syncope. Age greater than 65 years had similar sensitivity but much worse specificity compared with the set combined risk factors. CONCLUSION: Deaths related to syncope after an ED visit are low, especially in the first 6 months and can usually be predicted by risk factors.

Can emergency medical dispatch codes predict prehospital interventions for common 9-1-1 call types?

OBJECTIVE: The Medical Priority Dispatch System is an emergency medical dispatch (EMD) system that is widely used to categorize 9-1-1 calls and optimize resource allocation. This study evaluates the ability of EMD and non-EMD codes (calls not processed by EMD) to predict prehospital use of medications and procedures. METHODS: All transported prehospital patients placed in an EMD or non-EMD category that exceeded 500 total calls from January 1, 2004, to December 31, 2006, in a suburban California county were matched with their prehospital electronic patient care record. These records (N = 69,541) were queried for the following prehospital interventions: basic life support (BLS) care only, intravenous line placement only, medication given, and procedures. Advanced life support (ALS) interventions were defined as the administration of a medications or a procedure. The numbers of medications and procedures that were performed on patients in each EMD code were measured. RESULTS: Thirty-one of 141 EMD and non-EMD codes met inclusion criteria and comprised 73% of all calls during the study period. Non-EMD codes accounted for 48% of all calls in this study. Patients with shortness of breath, chest pain, diabetic problems, and altered mental status received the most medications. High rates of medication administration were also seen in the following codes: 17A (fall, 27%), 17B (fall, 14%), EMDX (unable to complete EMD process, 22%), MED (medical aid requested--details to follow, 26%), and MED3 (medical aid requested by police--code 3, 18%). Procedures were performed on only 0.9% of all calls, of which 75% were related to advanced airways. Higher rates of ALS interventions in higher-acuity categories (Alpha, Bravo, etc.) were seen in a number of EMD categories, including seizure, laceration/hemorrhage, sick, and traffic accident, but not seen in many categories, including abdominal pain, falls, and chest pain. CONCLUSIONS: This study demonstrated only a modest ability of the EMD system to predict which patients would require ALS intervention. There were limited differences noted in the ALS rates between the different codes (Alpha, Bravo, etc.) in the same complaint category, bringing into question the utility of the multiple subgroups. Non-EMD codes made up a large portion of calls (48%) and should be included in future studies.

The HOME Team: Evaluating the Effect of an EMS-based Outreach Team to Decrease the Frequency of 911 Use Among High Utilizers of EMS.

OBJECTIVES: The San Francisco Fire Department's (SFFD; San Francisco, California USA) Homeless Outreach and Medical Emergency (HOME) Team is the United States' first Emergency Medical Services (EMS)-based outreach effort using a specially trained paramedic to redirect frequent users of EMS to other types of services. The effectiveness of this program at reducing repeat use of emergency services during the first seven months of the team's existence was examined. METHODS: A retrospective analysis of EMS use frequency and demographic characteristics of frequent users was conducted. Clients that used emergency services at least four times per month from March 2004 through May 2005 were contacted for intervention. Patterns for each frequent user before and after intervention were analyzed. Changes in EMS use during the 15-month study interval was the primary outcome measurement. RESULTS: A total of 59 clients were included. The target population had a median age of 55.1 years and was 68% male. Additionally, 38.0% of the target population was homeless, 43.4% had no primary care, 88.9% had a substance abuse disorder at time of contact, and 83.0% had a history of psychiatric disorder. The HOME Team undertook 320 distinct contacts with 65 frequent users during the study period. The average EMS use prior to HOME Team contact was 18.72 responses per month (SD=19.40), and after the first contact with the HOME Team, use dropped to 8.61 (SD=10.84), P<.001. CONCLUSION: Frequent users of EMS suffer from disproportionate comorbidities, particularly substance abuse and psychiatric disorders. This population responds well to the intervention of a specially trained paramedic as measured by EMS usage. Tangherlini N , Villar J , Brown J , Rodriguez RM , Yeh C , Friedman BT , Wada P . The HOME Team: evaluating the effect of an EMS-based outreach team to decrease the frequency of 911 use among high utilizers of EMS. Prehosp Disaster Med. 2016;31(6):603-607.

ATP-dependent K(+) channels contribute to local metabolic coronary vasodilation in experimental diabetes.

This study tested whether ATP-dependent K(+) channels (K(ATP) channels) are an important mechanism of functional coronary hyperemia in conscious, instrument-implanted diabetic dogs. Data were collected at rest and during exercise before and after induction of diabetes with alloxan monohydrate (40-60 mg/kg intravenously). K(ATP) channels were inhibited with glibenclamide (1 mg/kg intravenously). In nondiabetic dogs, arterial plasma glucose concentration increased from 4.8 +/- 0.3 to 21.5 +/- 2.2 mmol/l 1 week after alloxan injection. In nondiabetic dogs, exercise increased myocardial oxygen consumption (MVO(2)) 3.4-fold, myocardial O(2) delivery 3.0-fold, and heart rate 2.4-fold. Coronary venous PO(2) decreased from 19.9 +/- 0.8 mmHg at rest to 14.8 +/- 0.8 mmHg during exercise. Diabetes significantly reduced myocardial O(2) delivery and lowered coronary venous PO(2) from 16.3 +/- 0.6 mmHg at rest to 13.1 +/- 0.9 mmHg during exercise. Glibenclamide did not alter the slope of the coronary venous PO(2) versus MVO(2) relationship in nondiabetic dogs. In diabetic dogs, however, glibenclamide further reduced myocardial O(2) delivery; coronary venous PO(2) fell to 9.0 +/- 1.0 mmHg during exercise, and the slope of the coronary venous PO(2) versus MVO(2) relationship steepened. These findings indicate that K(ATP) channels contribute to local metabolic coronary vasodilation in alloxan-induced diabetic dogs.

Efficacy of low-dose acetazolamide (125 mg BID) for the prophylaxis of acute mountain sickness: a prospective, double-blind, randomized, placebo-controlled trial.

The objective of this study was to determine the efficacy of low-dose acetazolamide (125 mg twice daily) for the prevention of acute mountain sickness (AMS). The design was a prospective, double-blind, randomized, placebo-controlled trial in the Mt. Everest region of Nepal between Pheriche (4243 m), the study enrollment site, and Lobuje (4937 m), the study endpoint. The participants were 197 healthy male and female trekkers of diverse background, and they were evaluated with the Lake Louise Acute Mountain Sickness Scoring System and pulse oximetry. The main outcome measures were incidence and severity of AMS as judged by the Lake Louise Questionnaire score at Lobuje. Of the 197 participants enrolled, 155 returned their data sheets at Lobuje. In the treatment group there was a statistically significant reduction in incidence of AMS (placebo group, 24.7%, 20 out of 81 subjects; acetazolamide group, 12.2%, 9 out of 74 subjects). Prophylaxis with acetazolamide conferred a 50.6% relative risk reduction, and the number needed to treat in order to prevent one instance of AMS was 8. Of those with AMS, 30% in the placebo group (6 of 20) versus 0% in the acetazolamide group (0 of 9) experienced a more severe degree of AMS as defined by a Lake Louise Questionnaire score of 5 or greater (p = 0.14). Secondary outcome measures associated with statistically significant findings favoring the treatment group included decrease in headache and a greater increase in final oxygen saturation at Lobuje. We concluded that acetazolamide 125 mg twice daily was effective in decreasing the incidence of AMS in this Himalayan trekking population.

Coronary blood flow control is impaired at rest and during exercise in conscious diabetic dogs.

This study tested whether diabetes mellitus impairs coronary blood flow control sufficiently to alter the balance between myocardial oxygen delivery and metabolism. Dogs (n = 7) were instrumented with catheters in the aorta and coronary sinus, and with a flow transducer on the circumflex coronary artery. Coronary blood flow, myocardial oxygen consumption (MVO2), heart rate and aortic pressure were measured at rest and during treadmill exercise before and after induction of diabetes with alloxan monohydrate (40 - 60 mg/kg). Arterial plasma glucose concentration increased from 4.6+/-0.2 mM in non-diabetic, control dogs to 20.2+/-2.3 mM one week after alloxan injection. In non-diabetic control dogs, exercise increased MVO2 3.1-fold, coronary blood flow 2.7-fold, and heart rate 2.4-fold. Coronary venous PO2 decreased from 19.4+/-0.6 mmHg at rest to 14.7+/-0.7 mmHg during exercise. Diabetes significantly attenuated exercise coronary hyperemia and reduced coronary venous PO2 at rest (15.6+/-0.5 mmHg) and during exercise (12.6+/-0.8 mmHg). Diabetes also significantly reduced myocardial oxygen delivery at each level of exercise. Acute hyperglycemia alone did not alter exercise-induced coronary vasodilation or reduce coronary venous PO2. These findings demonstrate that experimental diabetes attenuates functional coronary hyperemia and impairs the balance between coronary blood flow and myocardial metabolism. However, this deleterious effect is not related to acute hyperglycemia but to the chronic disease process of diabetes mellitus.