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Biomedical subjects

T D Valenzuela

Publications and source records attributed to T D Valenzuela.

At least 37 records · Page 2Linked to original sources
PubMed1993

Prospective validation of a new model for evaluating emergency medical services systems by in-field observation of specific time intervals in prehospital care.

STUDY OBJECTIVE: To develop and validate a new time interval model for evaluating operational and patient care issues in emergency medical service (EMS) systems. DESIGN/SETTING/TYPE OF PARTICIPANT: Prospective analysis of 300 EMS responses among 20 advanced life support agencies throughout an entire state by direct, in-field observation. RESULTS: Mean times (minutes) were response, 6.8; patient access, 1.0; initial assessment, 3.3; scene treatment, 4.4; patient removal, 5.5; transport, 11.7; delivery, 3.5; and recovery, 22.9. The largest component of the on-scene interval was patient removal. Scene treatment accounted for only 31.0% of the on-scene interval, whereas accessing and removing patients took nearly half of the on-scene interval (45.8%). Operational problems (eg, communications, equipment, uncooperative patient) increased patient removal (6.4 versus 4.5; P = .004), recovery (25.4 versus 20.2; P = .03), and out-of-service (43.0 versus 30.1; P = .007) intervals. Rural agencies had longer response (9.9 versus 6.4; P = .014), transport (21.9 versus 10.3; P < .0005), and recovery (29.8 versus 22.1; P = .049) interval than nonrural. The total on-scene interval was longer if an IV line was attempted at the scene (17.2 versus 12.2; P < .0001). This reflected an increase in scene treatment (9.2 versus 2.8; P < .0001), while patient access and patient removal remained unchanged. However, the time spent attempting IV lines at the scene accounted for only a small part of scene treatment (1.3 minutes; 14.1%) and an even smaller portion of the overall on-scene interval (7.6%). Most of the increase in scene treatment was accounted for by other activities than the IV line attempts. CONCLUSION: A new model reported and studied prospectively is useful as an evaluative research tool for EMS systems and is broadly applicable to many settings in a demographically diverse state. This model can provide accurate information to system researchers, medical directors, and administrators for altering and improving EMS systems.

Arizona↗
PubMed1992

Case and survival definitions in out-of-hospital cardiac arrest. Effect on survival rate calculation.

OBJECTIVE: To determine the effect of different case and survival definitions of out-of-hospital cardiac arrest on survival rate calculations. DESIGN: A 22-month case series of nontraumatic, out-of-hospital cardiac arrests. SETTING: Southwestern city (population, 400,000; area, 390 km2) with a two-tiered emergency response system consisting of emergency medical technicians and paramedics. PATIENTS: A consecutive sample of 372 patients found without palpable pulse of spontaneous respiration. MAIN OUTCOME MEASURES: Survival rate after cardiac arrest was calculated using three case definitions of arrest and two definitions of survival. RESULTS: Twenty percent of all patients survived to hospital admission and 6% survived to hospital discharge. Twenty-six percent of adults whose collapse was witnessed survived to hospital admission, and 10% survived to hospital discharge. Patients whose collapse was witnessed and who experienced initial ventricular fibrillation survived to hospital admission in 38% and to hospital discharge in 15% of cases. CONCLUSIONS: The survival rate after out-of-hospital cardiac arrest varies widely depending on the case and survival definitions selected. To facilitate intersystem comparison and assessment of interventions designed to improve outcome, the Utstein Consensus Conference recommended that case and survival definitions should be adopted by all prehospital emergency systems.

Aged↗
PubMed1992

Meeting the goals of academia: characteristics of emergency medicine faculty academic work styles.

STUDY OBJECTIVES: Emergency medicine faculty have 24-hour clinical responsibilities in addition to the academic requirements of research and administration/teaching. This study was undertaken to determine the existing and ideal work style of such faculty by professional rank, administrative title, and/or tenure versus clinical track. DESIGN: Data analysis from department or residency directors of Accreditation Council for Graduate Medical Education-approved emergency medicine residency programs. SETTING: ACGME-approved emergency medicine residency programs. TYPE OF PARTICIPANTS: Emergency medicine faculty. RESULTS: Ninety-three percent of programs submitted appropriate data. Programs averaged 11 full- and four part-time faculty. Mean time ranged from 15 to 30 hours per week with an average mean of 23 hours (48% of total work week) for clinical responsibilities, from ten to 32 hours per week with an average mean of 19 hours per week (38%) for administrative/teaching efforts, and from three to 14 hours per week with an average mean of seven hours per week (15%) for research. Total time averaged between 44 and 51 hours per week. Ideal work style emphasized less clinical time and a shorter work week. Responsibilities varied by rank, administrative position, and clinical versus tenure track. CONCLUSION: Emergency medicine faculty accomplish the clinical, research, and teaching/administrative demands of academia by increasing the number of faculty, varying the faculty responsibilities by rank and title, and shortening the total work week. Research time is extremely limited.

Clinical Medicine↗
PubMed1991

The impact of injury severity and prehospital procedures on scene time in victims of major trauma.

STUDY OBJECTIVE: To evaluate the relationship among injury severity, prehospital procedures, and time spent at the scene by paramedics for victims of major trauma. DESIGN: Retrospective study of 98 consecutive patients with an Injury Severity Score of more than 15 who were brought to a trauma center by fire department paramedics. SETTING: A medium-sized metropolitan emergency medical services (EMS) system and a Level I trauma center. RESULTS: There were 66 male and 32 female patients with a mean age of 34 years. Thirty-two patients (32.6%) died. Blunt and penetrating trauma accounted for 68.4% and 31.6% of cases, respectively. Thirty-three patients (33.7%) had successful advanced airway procedures, and 81 (82.7%) had at least one IV line started in the field. Analysis of scene time, prehospital procedures, and injury severity parameters revealed that more procedures were performed in the field on the more severely injured cases; that despite this, there was a trend toward shorter scene time for more severely injured patients; and that there was a mean scene time of 8.1 minutes. This is the shortest scene time reported to date for prehospital trauma care in an EMS system. CONCLUSION: Extremely short scene times can be attained without foregoing potentially life-saving advanced life support interventions in an urban EMS system with strong medical control. In such a system, the most severely injured victims may spend less time at the scene although more procedures are performed on them.

Adolescent↗
PubMed1991

Transmission of 'toxic strep' syndrome from an infected child to a firefighter during CPR.

Several cases of a toxic shocklike syndrome have been reported in the United States during the past five years in association with Streptococcus pyogenes infection. We report a case of a firefighter exposed during attempted CPR to the secretions of an S pyogenes-infected child. The firefighter developed an infection of the hand and subsequent febrile illness with hypotension, erythematous rash, renal failure, and hypocalcemia. Bacterial isolates of blood and cerebrospinal fluid from the deceased child were identical in type and exotoxin production with isolates grown from the hand wound of the firefighter. This is the first reported case of documented transmission of S pyogenes, causing a toxic shocklike syndrome in an emergency medical technician.

Adult↗
PubMed1991

A prospective analysis of injury severity among helmeted and nonhelmeted bicyclists involved in collisions with motor vehicles.

To evaluate the impact of helmet use on injury severity, patient information was prospectively obtained for all bicyclists involved in collisions with motor vehicles seen at a level-I trauma center from January 1986 to January 1989. Two hundred ninety-eight patients were evaluated; in 284 (95.3%, study group) cases there was documentation of helmet use or nonuse. One hundred sixteen patients (40.9%) wore helmets and 168 (59.1%) did not. One hundred ninety-nine patients (70.1%) had an ISS less than 15, while 85 (29.9%) were severely injured (ISS greater than 15). Only 5.2% of helmet users (6/116) had an ISS greater than 15 compared with 47.0% (79/168) of nonusers (p less than 0.0001). The mean ISS for helmet users was 3.8 compared with 18.0 for nonusers (p less than 0.0001). Mortality was higher for nonusers (10/168, 6.0%) than for helmet users (1/116, 0.9%; p less than 0.025). A striking finding was noted when the group of patients without major head injuries (246) was analyzed separately. Helmet users in this group still had a much lower mean ISS (3.6 vs. 12.9, p less than 0.001) and were much less likely to have an ISS greater than 15 (4.4% vs. 32.1%, p less than 0.0001) than were nonusers. In this group, 42 of 47 patients with an ISS greater than 15 (89.4%) were not wearing helmets. We conclude that helmet nonuse is strongly associated with severe injuries in this study population. This is true even when the patients without major head injuries are analyzed as a group; a finding to our knowledge not previously described.(ABSTRACT TRUNCATED AT 250 WORDS)

Accidents, Traffic↗
PubMed1991

Update: drug therapy for acute myocardial infarction.

Acute myocardial infarction is potentially a highly treatable disease. Immediate interventions are directed to decreasing tissue hypoxia with oxygen and improving bloodflow to ischemic myocardium using nitrates and thrombolytic agents. Cardiac workload should be reduced by eliminating endogenous catecholamine release with analgesia and sedation, and beta blockade in patients without CHF to decrease heart rate and myocardial oxygen demand. Treatment of the complications of AMI include dysrhythmia prophylaxis, monitoring and specific therapy. Treatment of pump failure includes using vasodilators, vasopressors and positive inotropic agents. Early recognition and timely initiation of appropriate therapy should be every physician's goal.

Humans↗
PubMed1990

Computer modeling of emergency medical system performance.

Emergency medical services (EMS) system managers face difficult problems when determining the need for system expansion and unit deployment. Information relevant to the decision is often limited and frequently not in a usable format. This lack of usable information often results in decisions that create less-than-optimal EMS systems. A constant search for greater efficiency prompted the development of a computer simulation model to analyze the current EMS system operated by the Tucson Fire Department and to provide statistical information on the effects of potential vehicle base locations on system performance. The simulation model generates data that reflect a variety of parameters necessary in base location analysis. Included in the performance statistics for each unit and for the entire system are indicators of unit use rates, minimum and maximum response times, and proportion of calls reached within the critical response time of eight minutes or less. The model has been carefully validated and used in unit redeployment and unit activation in Tucson, Arizona.

Arizona↗
PubMed1990

Critical care air transportation of the severely injured: does long distance transport adversely affect survival?

Civilian aeromedical transportation systems, both fixed and rotary wing, have proliferated since the middle 1970s. However, outcome data substantiating the benefit of these services have been slow in coming. From February 22, 1982, through March 5, 1984, Airlift Northwest transported 118 trauma patients (aged 15 years and older) an average distance of 340 miles (range, 100 to 800 miles) with fixed-wing aircraft. The in-hospital mortality for this group was 19% compared with 18% for a comparable group of trauma patients who were ground-transported from within the city limits of Seattle, Washington. The two groups did not differ significantly in age, Injury Severity Score, or Glasgow Coma Score. These results suggest that some part of the clinical benefit of a regional trauma center may be extended up to 800 miles with no increase in transport-related mortality.

Adolescent↗
PubMed1990

Prehospital cardiac arrest: the impact of witnessed collapse and bystander CPR in a metropolitan EMS system with short response times.

OBJECTIVE: Numerous studies have shown initiation of bystander CPR to significantly improve survival from prehospital cardiac arrest. However, in emergency medical services (EMS) systems with very short response times, bystander CPR has not been shown to impact outcome. The purpose of this study was to determine the effect of bystander CPR on survival from out-of-hospital cardiac arrest in such a system. DESIGN: Prehospital, hospital, and death certificate data from a medium-sized metropolitan area were retrospectively analyzed for adult, nontraumatic cardiac arrest during a 16-month period. RESULTS: A total of 298 patients met study criteria. One hundred ninety-five arrests (65.4%) were witnessed, and 103 (34.6%) were unwitnessed. Twenty-five witnessed victims (12.8%) were discharged alive, whereas no unwitnessed victims survived (P less than .001). Patients suffering a witnessed episode of ventricular fibrillation/tachycardia (VF/VT) were more likely to survive (21.9%) than were other patients (2.0%, P less than .0001). Among witnessed patients, initiation of bystander CPR was associated with a significant improvement in survival (20.0%) compared with the no-bystander CPR group (9.2%, P less than .05). Bystander CPR was also associated with improved outcome when witnessed patients with successful prehospital resuscitation were evaluated as a group; 18 had bystander CPR, of whom 13 (72.2%) survived compared with only 12 of 38 patients with no bystander CPR (31.6%, P less than .01). CONCLUSION: Our data revealed improved survival rates when bystander CPR was initiated on victims of witnessed cardiac arrest in an EMS system with short response times.

Adult↗
PubMed1990

Prehospital data entry compliance by paramedics after institution of a comprehensive EMS data collection tool.

OBJECTIVE: To determine the completeness of data entry by paramedics after an extensive modification of the prehospital first-care form in an urban emergency medical services (EMS) system. DESIGN: Comprehensive medical information was added to the EMS data collection tool used by a metropolitan fire department. We evaluated the frequency of failure to enter data pertaining to medical assessment and/or treatment of victims of cardiac arrest after implementation of the system. RESULTS: Failure to enter data in the first month was compared with two subsequent two-month blocks. A high rate of noncompliance existed in the first month (all medical data were missing in 24.6%). However, the subsequent two months revealed a marked decline in noncompliance (4.4%, P less than .001). This decline was maintained after a three-month interim (5.0%, P less than .001). CONCLUSION: Data entry noncompliance can be a significant problem after implementation of a new prehospital data collection system. However, compliance can be markedly improved over a relatively short period. Because EMS system evaluation is based on data collected in the field. EMS researchers and administrators must be aware of the data entry compliance rate in their system when attempting to make conclusions from such information.

Adolescent↗
PubMed1990

Cost-effectiveness analysis of paramedic emergency medical services in the treatment of prehospital cardiopulmonary arrest.

STUDY OBJECTIVES: 1) Identification of marginal costs associated with prehospital resuscitation of cardiopulmonary arrest; 2) Determination of cost effectiveness for such resuscitation; and 3) Comparison of cost effectiveness of paramedic care with selected other medical interventions. DESIGN: Retrospective review of 190 cases of out-of-hospital cardiac arrest. SETTING: City limits of a midsized southwestern city. The events studied took place outside of medical facilities. TYPE OF PARTICIPANTS: Victims of out-of-hospital cardiac arrest for whom the EMS system was activated by a 911 telephone request for emergency medical assistance. MEASUREMENTS AND MAIN RESULTS: The cost, including training, personnel, equipment, and response time maintenance, per year of life saved was found to be $8,886.00 for paramedic care. This result was compared with published cost-effectiveness figures for heart transplantation, liver transplantation, bone marrow transplantation, and chemotherapy for acute leukemia. Paramedic care was more cost effective, as measured by cost per year of life saved, than organ transplantation and chemotherapy for acute leukemia. CONCLUSION: Out-of-hospital treatment by paramedics of cardiopulmonary arrest is more cost effective than heart, liver, bone marrow transplantation, or curative chemotherapy for acute leukemia.

Arizona↗
PubMed1990

Geriatric injury: an analysis of prehospital demographics, mechanisms, and patterns.

STUDY OBJECTIVE: To evaluate emergency medical services (EMS) system use, injury mechanisms, and prehospital assessments among elderly victims of trauma. DESIGN: We analyzed all prehospital data for injuries among patients 70 years old or older for whom 911 EMS dispatch was requested in a medium-sized metropolitan area during a 12-month period. RESULTS: A total of 1,154 cases occurred (women, 65.1%), which represented 30.3% of all 911 dispatches involving elderly patients. Injury mechanisms were fall (60.7%), motor vehicle accident (MVA; 21.5%), fight (2.4%), accidental poisoning (2.3%), and choking (2.1%). Persons in their 90s had a lower frequency of MVAs (3.4%) than did younger patients (23.0%) (P less than .005). The most frequent injuries determined by prehospital assessment were head or face (25.1%), upper extremity (17.2%), hip (14.5%), lower extremity (13.8%), back (9.8%), and chest or abdomen (5.0%). The frequency of serious neurologic injuries was less for falls or MVAs than for other mechanisms (P less than .005). Suspected hip (P less than .001) and pelvic (P less than .005) injuries occurred more frequently during falls than during other mechanisms of injury, whereas back injuries occurred most frequently in MVAs (P less than .001). Seventy-one fall victims (10.1%) had suspected medical causes of their fall. Twelve patients (1.0%) were in cardiac arrest. CONCLUSION: We report injury patterns and mechanisms among elderly victims of trauma presenting to an EMS system. A knowledge of these patterns will be useful to emergency physicians and EMS administrators.

Accidents↗
PubMed1990

Banning alcohol in a major college stadium: impact on the incidence and patterns of injury and illness.

To evaluate the effect of banning alcohol on the incidence of injuries and illness among spectators, we reviewed 4 years (1983 to 1986) of medical incident reports from a major collegiate football stadium. At no time had alcoholic beverages been sold inside the stadium, but before 1985, fans were allowed to bring alcohol into the stadium. In 1985, this practice was banned. During the study period, 340 medical incidents (M = 12.6/game) were reported. Several alterations of specific injury/illness patterns were noted after initiation of the ban: heat-related illness occurred more frequently before initiation of the ban, whereas extremity injuries and syncope (fainting from coronary insufficiency) occurred with greater frequency afterwards. The injury/illness rates per 10,000 fans were 2.95 in 1983, 2.45 in 1984, 1.92 in 1985, and 3.48 in 1986. There was no significant change in the overall incident rate after the ban. Evaluation of medical incidents revealed an alteration in specific injury/illness patterns but no change in overall incidence after institution of the ban. Future investigations are needed to elucidate more clearly the impact of banning alcohol on injury/illness rates and patterns at mass gatherings.

Adolescent↗
PubMed1989

Thermal stability of prehospital medications.

To evaluate the effect of prolonged environmental extremes on common prehospital medications, four identical sets of 23 drugs were placed in a simulated environment for up to four weeks. Subsequently, the samples were analyzed by gas chromatography-mass spectrometry for evidence of degradation byproducts. Twenty-one of the 23 samples showed no breakdown products; however, isoproterenol demonstrated 11% loss of parent compound after four weeks of environmental exposure. Epinephrine manifested a change in its ionized state after exposure to heat; the physiologic effect of this change was not determined. Our results suggest that rural and suburban emergency medical services providers, whose medications may not be replaced until they are used in patient care, must monitor their drug boxes' duration of exposure to uncontrolled conditions.

Arizona↗
PubMed1989

Evaluation of EMS management training offered during emergency medicine residency training.

Physician involvement in the provision of both direct and indirect medical control to emergency medical providers is critical to the effective operation of an emergency medical services (EMS) system. We conducted a survey of all accredited emergency medicine residency programs in the United States to determine the content of EMS instruction provided to these physicians-in-training. The majority of programs provide an introduction to direct medical control, to EMS organizational structure, and the opportunity to participate in EMS-related research. Less than 65%, however, provide formal instruction in EMS risk management or quality assurance or the opportunity to observe policy-making bodies related to EMS. The importance placed on EMS during residency training is variable. EMS is the domain of emergency medicine, and adequate training of residents for these responsibilities is imperative.

Curriculum↗