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Biomedical subjects

M P Larsen

Publications and source records attributed to M P Larsen.

At least 19 recordsLinked to original sources
PubMed1998

Gender differences in reported symptoms for acute myocardial infarction: impact on prehospital delay time interval.

A retrospective observational study using database registry of consecutive patients admitted to 16 King County hospital Coronary Care Units (CCU) was conducted to assess gender differences in symptom presentation for acute myocardial infarction (AMI) and investigate how symptom presentation relates to prehospital delay time interval from acute symptom onset to emergency department (ED) presentation. Between January 1991 and February 1993, 4,497 patients were admitted to the CCUs with diagnosed AMI. Accredited record technicians abstracted age, gender, race, transport method, symptom presentation (chest pain, sweating, nausea, shortness of breath, epigastric pain, and fainting), delay time interval between acute symptom onset and presentation to hospital ED, and discharge diagnosis from the patients' medical records. After adjusting for age and history of diabetes, no gender differences remained for frequencies of chest pain, fainting, or epigastric pain. Women reported more nausea and shortness of breath but less sweating than men as symptoms of AMI. Chest pain, sweating, and fainting were associated with decreasing delay time intervals. Age, gender, histories of AMI and diabetes, and transport choice were also significantly related to delay time interval. These results show that gender differences occur in AMI symptom experience. However, how symptoms relate to the gender gap in delay time interval is not clear. These findings suggest that health care professionals need to tailor information about possible symptoms of AMI to the patient's gender, age, and medical history.

Age Factors↗
PubMed1998

Automated external defibrillators: skill maintenance using computer-assisted learning.

OBJECTIVE: To determine whether computer-assisted learning (CAL) can maintain the automated external defibrillation (AED) skills of emergency medical technicians (EMTs). METHODS: The authors conducted a 1-year prospective comparison of an AED-skill training software program, running on desktop computers, with traditional instructor-led training. The subjects were experienced EMT-Ds (EMT-defibrillation), already trained in automated defibrillation (n = 105) employed as full-time professional EMT-D/firefighters. Two of the 3 groups (groups A and C) in the study were assigned to use the CAL program for 6 months. The third group (group B) remained on the normal, instructor-led training regimen. Pre- and poststudy skill levels were measured using a skills performance test. RESULTS: A secular trend of improved mean treatment scores was observed across all 3 groups [mean rise of 0.49 point (p = 0.01), repeated-measures analysis of variance]. There were no differences between training groups in the increase in performance scores (p = 0.3). The 1-time cost of supplying the CAL program to the 105 EMT-Ds was $1,575, significantly less than the $3,240-per-year cost associated with instructor-led training. CONCLUSIONS: The authors observed satisfactory AED skill maintenance for experienced EMT-Ds using CAL to replace 2 of 4 quarterly instructor-led skills reviews. CAL has cost and convenience advantages over instructor-based skill maintenance and is an acceptable alternative.

Clinical Competence↗
PubMed1997

Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model.

BACKGROUND: The study objective was to develop a simple, generalizable predictive model for survival after out-of-hospital cardiac arrest due to ventricular fibrillation. METHODS AND RESULTS: Logistic regression analysis of two retrospective series (n=205 and n=1667, respectively) of out-of-hospital cardiac arrests was performed on data sets from a Southwestern city (population, 415,000; area, 406 km2) and a Northwestern county (population, 1,038,000; area, 1399 km2). Both are served by similar two-tiered emergency response systems. All arrests were witnessed and occurred before the arrival of emergency responders, and the initial cardiac rhythm observed was ventricular fibrillation. The main outcome measure was survival to hospital discharge. Patient age, initiation of CPR by bystanders, interval from collapse to CPR, interval from collapse to defibrillation, bystander CPR/collapse-to-CPR interval interaction, and collapse-to-CPR/collapse-to-defibrillation interval interaction were significantly associated with survival. There was not a significant difference between observed survival rates at the two sites after control for significant predictors. A simplified predictive model retaining only collapse to CPR and collapse to defibrillation intervals performed comparably to the more complicated explanatory model. CONCLUSIONS: The effectiveness of prehospital interventions for out-of-hospital cardiac arrest may be estimated from their influence on collapse to CPR and collapse to defibrillation intervals. A model derived from combined data from two geographically distinct populations did not identify site as a predictor of survival if clinically relevant predictor variables were controlled for. This model can be generalized to other US populations and used to project the local effectiveness of interventions to improve cardiac arrest survival.

Adolescent↗
PubMed1997

'Call fast, Call 911': a direct mail campaign to reduce patient delay in acute myocardial infarction.

OBJECTIVES: A 10-month direct mail campaign was implemented to increase use of emergency medical services via 911 calls and to reduce prehospital delay for individuals experiencing acute myocardial infarction symptoms. METHODS: This prospective, randomized, controlled trial involved three intervention groups (receiving brochures with informational, emotional, or social messages) and a control group. RESULTS: Intervention effects were not observed except for individuals who had a history of acute myocardial infarction and who were discharged with a diagnosis of acute myocardial infarction; their 911 use was meaningfully higher in each intervention group than in the control group. CONCLUSIONS: The mailings affected only the individuals at greatest risk.

Adult↗
PubMed1996

Incidence of cardiac arrest during self-transport for chest pain.

STUDY OBJECTIVE: To assess the incidence of cardiac arrest among patients who use self-transport to seek medical care for chest pain. METHODS: This was a retrospective cohort study of patients admitted to a CCU for suspected acute myocardial infarction (AMI) and patients experiencing out-of-hospital cardiac arrest preceded by symptoms in King County, Washington, between January 1, 1992, and July 31, 1994. Participants were identified through use of the databases compiled by the Myocardial infarction Triage and intervention Trial, which reviewed medical records in all area hospitals, and the Cardiac Arrest Surveillance System, which tracks all incidences in which CPR is performed by EMS personnel in King County. Patients whose sudden cardiac arrests were not preceded by symptoms were excluded. Hospital records were abstracted to find the means of transport for patients admitted to CCUs. For cardiac arrest patients, the medical history, presence of symptoms, means of transport, and prehospital death information were abstracted from paramedic field reports. Outcome (admission, discharge, or in-hospital death) was obtained from hospital records. An event cause (cardiac or other) was determined from death certificates, hospital records, or consultation with private physicians. RESULTS: During the 30-month study period, 13,187 patients sought help for cardiac symptoms and were either admitted to a CCU or died before admission after calling 911. A majority, 7,393 (59%), were transported by emergency medical services, and 5,182 (41%) used private transportation to obtain medical care; the means of transport could not be determined for 612 patients. Of the EMS group, 6,978 were admitted to the hospital without experiencing prehospital cardiac arrest, and 415 (5.6%) arrested before arriving at the hospital. Of the group using private transportation, 5,164 were admitted without arresting and 18 (.35%) arrested before arrival, after which 911 was called (P < .001). CONCLUSION: The incidence of cardiac arrest among patients who attempted to reach the hospital by private transportation was very low compared with the incidence among those who chose the EMS system for transport. This suggests that patient self-selection occurs, with the more seriously ill patients more commonly calling 911 for transport.

Aged↗
PubMed1996

Papillary urothelial hyperplasia. A precursor to papillary neoplasms.

Precursor lesions of papillary urothelial neoplasms have not been well characterized. We reviewed the surgical pathology files of the Johns Hopkins Hospital and three regional hospitals from 1992 to present. Sixteen cases of papillary hyperplasia, defined as undulating urothelium arranged into thin mucosal papillary folds, were identified (in 11 men and five women: age range, 40-89 years). Relative to the diagnosis of papillary hyperplasia, nine patients had a history of papillary urothelial neoplasms; in one of these cases, the patient also had subsequent papillary urothelial neoplasms, and two of these patients had concurrent papillary urothelial neoplasms with papillary hyperplasia. In one of these nine cases, papillary hyperplasia arose in the scar of a prior papillary urothelial neoplasm. In two cases, the patients had concurrent, yet no prior history, of papillary urothelial neoplasms. Of these 11 cases, three had multiple resections showing papillary hyperplasia over time. In case 12, the patient had a history of moderate urothelial atypia. The remaining four patients had no history of papillary urothelial neoplasms or urothelial atypia. We describe papillary hyperplasia as a well-defined entity that is usually asymptomatic and generally found on routine follow-up cystoscopy for papillary urothelial neoplasms. Papillary hyperplasia appears to be a precursor lesion of low-grade papillary urothelial neoplasms.

Adult↗
PubMed1995

Reasons patients with chest pain delay or do not call 911.

STUDY OBJECTIVE: To determine the reasons patients with suspected acute myocardial infarction (AMI) delay seeking medical care or do not call 911. DESIGN: Telephone interview of patients hospitalized with suspected AMI. SETTING: Nine hospitals in King County, Washington. PARTICIPANTS: Patients admitted to a CCU or ICU between October 1, 1986, and December 31, 1987, with suspected AMI occurring out-of-hospital. Spouses of patients who met criteria but died during the hospitalization also participated. INTERVENTIONS: Hospital records were reviewed, and a 20-minute telephone interview was conducted of patients who reside in King County but do not live in an extended care facility. MEASUREMENTS: Patient demographics, cardiac history, symptoms, time of acute symptom onset, time of emergency department arrival, method of transportation, discharge diagnosis, and hospital outcome were abstracted from hospital records. Circumstances leading to the hospitalization, reasons for delay in seeking care, and reasons for not calling 911 were determined in the telephone interview. RESULTS: In a 15-month period, 5,207 patients were hospitalized for suspected AMI in King County, Washington. Twenty-seven percent had AMI. Median patient delay between symptom onset and hospital arrival was 2 hours. Paramedics transported 45% of all patients. A representative subset of patients (2,316) were interviewed. The main reasons for delay were because the patient thought that the symptoms would go away, because the symptoms were not severe enough, and because the patient thought that the symptoms were caused by another illness. The main reasons for not calling 911 were because the symptoms were not severe enough, because the patient did not think of calling 911, and because the patient thought that self-transport would be faster because of his or her close location to the hospital. CONCLUSION: Maximal benefit from thrombolytic therapy is not realized in a substantial proportion of patients with AMI because of delays in seeking medical care. Knowledge of the reasons patients delay or do not call 911 can help focus efforts on achieving more rapid treatment of patients with AMI.

Adult↗
PubMed1994

Expected death and unwanted resuscitation in the prehospital setting.

STUDY OBJECTIVE: To determine the outcome, location, preexisting conditions, and resuscitation wishes of prehospital cardiac arrest patients. DESIGN: Retrospective review of paramedic and emergency medical technician run reports. SETTING: Urban area with a two-tiered emergency medical services response system covering an area of 2,128 square miles and serving a population of 1,413,900 (in 1988). PARTICIPANTS: All prehospital cardiac arrest patients to which the King County, Washington, Emergency Medical Services (KCEMS) system responded to during a 12-month period. Unless decapitation, decomposition, or dependent lividity existed, all cardiac arrest patients in the KCEMS system received full resuscitative efforts. MEASUREMENTS: We analyzed run reports from 694 cardiac arrest patients, excluding all cardiac arrests from trauma, overdose, or drowning, or obvious signs of extended downtime such as decomposition or dependent lividity. We defined an unwanted resuscitation as a resuscitation attempt despite written or verbal requests by the patient, family, or private physician. We defined a patient as having severe, chronic disease if the run report listed one or more conditions associated with poor survival rates after inpatient CPR. These included cancer, cerebral vascular accident, dementia, renal failure, dialysis, AIDS, thoracic or abdominal aneurysms, cirrhosis, or if the patient was bedridden or was receiving chronic home nursing care. MAIN RESULTS: Overall 16% (103 of 633) of all cardiac arrest patients survived to hospital discharge. Seven percent (47 of 633) of all cardiac arrest patients fit the unwanted resuscitation definition; 2% (one of 47) survived to hospital discharge. Twenty-five percent (158 of 633) of cardiac arrest patients fit the definition of severe chronic disease; 8% (12 of 158) survived to hospital discharge. CONCLUSION: Severe chronic disease and unwanted resuscitation patients comprised one-third of all resuscitation attempts by KCEMS during a 12-month period. Both groups had lower survival rates compared to cardiac arrest patients who did not have severe chronic disease or indications of unwanted resuscitation.

Advance Directives↗
PubMed1994

Impact of direct mail intervention on knowledge, attitudes, and behavioral intentions regarding use of emergency medical services for symptoms of acute myocardial infarction.

This study evaluated a direct mail intervention called the "Call Fast, Call 911" campaign designed to increase use of emergency medical services for symptoms of acute myocardial infarction. The campaign was targeted at individuals over the age of 50. Persons over 50 years of age (N = 130,000) in King County, Washington, were randomly assigned to intervention or control groups. Individuals in the intervention groups received six direct mail pieces over a 1-year period encouraging them to call 911 quickly in response to chest pain. A postintervention telephone survey of a random sample of households (N = 434) assessed the impact of the campaign on knowledge, attitudes, and behavioral intentions regarding use of emergency medical services for symptoms of acute myocardial infarction. The results showed no significant differences between intervention and control groups in terms of knowledge of AMI. However, there were significant differences in beliefs and behavioral intentions to call 911 in a cardiac emergency.

Aged↗
PubMed1993

Out-of-hospital transcutaneous pacing by emergency medical technicians in patients with asystolic cardiac arrest.

BACKGROUND: Transcutaneous cardiac pacemakers generate electrical stimuli that pace the heart through external electrodes that adhere to the chest wall. Transcutaneous pacing has been useful in some patients with bradycardia, but its efficacy in patients with asystole and full cardiac arrest has been limited, possibly because of delays in the initiation of pacing. We studied the efficacy of early transcutaneous pacing in patients with out-of-hospital asystolic cardiac arrest. METHODS: For three years we provided transcutaneous pacemakers to about half the fire districts in a large emergency-medical-services system (the intervention group). In these districts, we authorized emergency medical technicians (EMTs) to begin transcutaneous pacing in patients with cardiac arrest and primary asystole or post-defibrillation asystole. Pacing was done as early as possible, before endotracheal intubation or intravenous medication. EMTs in the other fire districts (the control group) treated similar patients with basic cardiopulmonary resuscitation but without transcutaneous pacing. RESULTS: The EMTs in the intervention group initiated transcutaneous pacing in 112 of the 278 patients with primary asystole. Of these patients, 22 (8 percent) were admitted to the hospital, and 11 (4 percent) were discharged. Among the 259 patients treated by the EMTs in the control group, 21 (8 percent) were admitted to the hospital, and 5 (2 percent) were discharged. The two groups did not differ significantly with respect to the rate of hospital admission or survival. Survival after early pacing for post-defibrillation asystole was no better than survival after pacing for primary asystole. CONCLUSIONS: Transcutaneous pacing appears to offer no benefit in patients with asystolic cardiac arrest, even when it is performed as early as possible by EMTs in the field. Our data suggest that the widespread implementation of early transcutaneous pacing for out-of-hospital asystolic cardiac arrest would be ineffective.

Cardiac Pacing, Artificial↗
PubMed1993

Prehospital delay interval for patients who use emergency medical services: the effect of heart-related medical conditions and demographic variables.

STUDY OBJECTIVE: To investigate the effect of heart-related medical conditions and demographic variables on patients' tendency to delay contacting emergency medical services for symptoms of acute myocardial infarction. TYPE OF PARTICIPANTS: A sample of 2,947 patients with acute myocardial infarction but no cardiac arrest, transported by paramedics to the coronary care units of 19 hospitals in King County, Washington, between January 1988 and April 1991. MEASUREMENTS: Patient record abstracts contained information on medical history, age, gender, delay interval, and means of transportation. RESULTS: Multiple regression analyses showed that prehospital delay interval was significantly greater for individuals who were older and female and who had a history of angina, congestive heart failure, or diabetes. CONCLUSION: It is important to investigate further how people interpret and evaluate their symptoms in light of other medical conditions. It is also critical to find out why women delay longer than men and why older individuals delay longer than younger people before they contact emergency medical services. Interventions need to be developed that are targeted at populations at risk for delaying use of emergency medical services for acute myocardial infarction symptoms. These interventions must legitimize the use of emergency medical services and encourage patients to act quickly when confronted with acute myocardial infarction symptoms.

Adult↗
PubMed1993

Predicting survival from out-of-hospital cardiac arrest: a graphic model.

STUDY OBJECTIVE: To develop a graphic model that describes survival from sudden out-of-hospital cardiac arrest as a function of time intervals to critical prehospital interventions. PARTICIPANTS: From a cardiac arrest surveillance system in place since 1976 in King County, Washington, we selected 1,667 cardiac arrest patients with a high likelihood of survival: they had underlying heart disease, were in ventricular fibrillation, and had arrested before arrival of emergency medical services (EMS) personnel. METHODS: For each patient, we obtained the time intervals from collapse to CPR, to first defibrillatory shock, and to initiation of advanced cardiac life support (ACLS). RESULTS: A multiple linear regression model fitting the data gave the following equation: survival rate = 67%-2.3% per minute to CPR-1.1% per minute to defibrillation-2.1% per minute to ACLS, which was significant at P < .001. The first term, 67%, represents the survival rate if all three interventions were to occur immediately on collapse. Without treatment (CPR, defibrillatory shock, or definitive care), the decline in survival rate is the sum of the three coefficients, or 5.5% per minute. Survival rates predicted by the model for given EMS response times approximated published observed rates for EMS systems in which paramedics respond with or without emergency medical technicians. CONCLUSION: The model is useful in planning community EMS programs, comparing EMS systems, and showing how different arrival times within a system affect survival rate.

Emergency Medical Services↗
PubMed1992

Incidence of agonal respirations in sudden cardiac arrest.

STUDY OBJECTIVE: To discover the frequency of agonal respirations in cardiac arrest calls, the ways callers describe them, and discharge rates associated with agonal respirations. DESIGN: We reviewed taped recordings of calls reporting cardiac arrests and emergency medical technician and paramedic incident reports for 1991. Arrests after arrival of emergency medical services were excluded. SETTING: King County, Washington, excluding the city of Seattle. PARTICIPANTS: Four hundred forty-five persons with out-of-hospital cardiac arrests receiving emergency medical services. INTERVENTIONS: Telephone CPR, emergency medical technicians-defibrillation, and advanced life support by paramedics. MEASUREMENTS AND MAIN RESULTS: Any attempts at breathing described by callers were identified, as well as whether agonal respirations could be heard by dispatcher, emergency medical technicians, or paramedics. Agonal respirations occurred in 40% of 445 out-of-hospital cardiac arrests. Callers described agonal breathing in a variety of ways. Agonal respirations were present in 46% of arrests caused by cardiac etiology compared with 32% in other etiologies (P < .01). Fifty-five percent of witnessed arrests had agonal activity compared with 16% of unwitnessed arrests (P < .001). Agonal respirations occurred in 56% of arrests with a rhythm of ventricular fibrillation compared with 34% of cases with a nonventricular fibrillation rhythm (P < .001). Twenty-seven percent of patients with agonal respirations were discharged alive compared with 9% without them (P < .001). CONCLUSION: There is a high incidence of agonal activity associated with out-of-hospital cardiac arrest. Presence of agonal respirations is associated with increased survival. These findings have implications for public CPR training programs and emergency dispatcher telephone CPR programs.

Emergency Medical Services↗
PubMed1992

The epidemiology of cardiac arrest in young adults.

STUDY OBJECTIVE: To describe the epidemiology of cardiac arrest in young adults and to determine if there are characteristics unique to this group in terms of etiology, rhythm, and outcome. DESIGN: Retrospective, case review. SETTING: King County, Washington. TYPE OF PARTICIPANTS: All out-of-hospital victims of cardiac arrest who received emergency aid. MEASUREMENTS: The etiology, cardiac rhythm, and outcome were identified for each case. MAIN RESULTS: During the 13-year period from 1976 to 1989, there were 8,054 cardiac arrests; 252 of these were among young adults 18 to 35 years of age. Of those 252 cases, 61 (24%) were caused by ischemic heart disease, and 60 (24%) were caused by overdose. Asystole was the most common rhythm (48%), followed by ventricular fibrillation or tachycardia (31%). Long-term survival following these rhythms was 4% and 28%, respectively. In terms of age, etiology, and rhythm, young adults appear to represent a transitional group between children and older adults. There were no unique characteristics specific to young adults. Long-term survival is dependent more on rhythm than on age. CONCLUSION: In terms of age, etiology, and rhythm, young adults appear to represent a transitional group between children and older adults.

Adolescent↗
PubMed1991

Numerators, denominators, and survival rates: reporting survival from out-of-hospital cardiac arrest.

This study demonstrates the effect of different denominators on the survival rate from out-of-hospital cardiac arrest. We retrospectively analyzed data from a cardiac arrest surveillance system in King County, Washington during the years 1976 to 1988, and calculated survival rates using eight different definitions of denominators. The eight survival rates ranged from 16% to 49% discharge from hospital. The denominator for the lowest survival rate included all cases of cardiac arrest for whom emergency medical services personnel started cardiopulmonary resuscitation. The denominator for the highest survival rate included: all cases of presumed cardiac etiology; first recorded rhythm was ventricular fibrillation; collapse witnessed; cardiopulmonary resuscitation started by bystanders within 4 minutes; and definitive care provided within 8 minutes. The definition of cases included in the denominator can dramatically effect the resultant survival rate. There must be national and international agreement about definitions of denominators for valid cross community comparisons.

Emergencies↗
PubMed1991

Can stage A1 tumor extent be predicted by transurethral resection tumor volume, per cent or grade? A study of 64 stage A1 radical prostatectomies with comparison to prostates removed for stages A2 and B disease.

We studied 64 totally embedded radical prostatectomy specimens of stage A1 prostate cancer. The transurethral resection specimens were studied and compared to previously studied stages A2 and B cancer in which tumor volumes also were calculated. At radical prostatectomy 6% of the specimens had no residual cancer, 74% had minimal cancer and 20% had substantial cancer. Although most stages A2 and B tumors were larger, there was overlap among all stages. Transurethral resection tumor volume, per cent and grade were not statistically correlated with either radical prostatectomy residual tumor volume, or whether tumor was classified as minimal or substantial. Gleason sum 2 to 4 versus 5 to 7 tumor on transurethral resection showed no difference in predicting radical prostatectomy residual tumor or minimal versus substantial tumor status. Because 20% of all stage A1 cancers have substantial tumor at radical prostatectomy unpredictable by transurethral resection, radical prostatectomy remains an option for young men with stage A1 prostate cancer.

Aged↗
PubMed1991

Dispatcher-assisted telephone CPR: common delays and time standards for delivery.

STUDY OBJECTIVES: To determine the rate of bystander CPR before and after implementation of a telephone CPR program in King County; to determine the reasons for dispatcher delays in identifying patients in cardiac arrest in delivering CPR instructions over the telephone; and to suggest time standards for delivery of the telephone CPR message. DESIGN: An ongoing cardiac arrest surveillance system to calculate the annual bystander CPR rates from 1976 through 1988. Two hundred sixty-seven taped recordings of calls reporting cardiac arrests to nine emergency dispatch centers during 1988 were reviewed and timed. SETTING: King County, Washington, excluding the city of Seattle. PARTICIPANTS: Two hundred sixty-seven persons with out-of-hospital cardiac arrests receiving emergency medical services. Arrests in doctors' offices, clinics, or nursing homes were excluded. INTERVENTIONS: Dispatcher-assisted telephone CPR. MEASUREMENTS AND MAIN RESULTS: The rate of bystander CPR increased from 32% (1976 through 1981) to 54% (1982 through 1988) after implementation of the dispatcher-assisted telephone CPR program, although an increase in survival could not be demonstrated. The median time for dispatchers to identify the problem was 75 seconds; to deliver the early protocols, 19 seconds; to deliver the ventilation instructions, 25 seconds; and to deliver compression instructions, 30 seconds. The total time to deliver the entire CPR message was 2.3 minutes. The most frequent cause for delay was unnecessary questions (57%) with questions about patient age asked most frequently (32%). Other causes included the caller not being near the patient (29%) and deviations from protocol (22%). CONCLUSION: In a metropolitan emergency medical services system, a dispatcher-assisted telephone CPR program was associated with an increase in bystander CPR. Delays in proper delivery of telephone CPR can be minimized through training.

Emergency Medical Service Communication Systems↗