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Biomedical subjects

E Criss

Publications and source records attributed to E Criss.

At least 19 recordsLinked to original sources

A simulation model for evaluating a set of emergency vehicle base locations: development, validation, and usage.

This paper describes our experiences in developing a simulation model for evaluating a set of emergency response vehicle base locations. The project was undertaken jointly by the University of Arizona and the Tucson Fire Department. The issues of model development, data collection, model validation, and experimentation are discussed. The critical nature of the problem and the clients' lack of experience with mathematical models, made model validation the major step in gaining user acceptance. We show that looking solely at standard performance statistics such as the calls successfully serviced, may lead to the acceptance of an invalid model. We also show that the high level of detail used in many simulation models for evaluating base locations is unnecessary in the current case. An analysis evaluating two alternative sets of locations for the Tucson system is discussed.

Ambulances↗

Railroad accidents: a metropolitan experience of death and injury.

A review of all railroad-related deaths and significant injuries that occurred in a medium-sized metropolitan area from January 1, 1979, to June 30, 1986, was conducted. Autopsy reports were obtained for each fatality, and pre-hospital data were retrieved for all railroad-related injuries resulting in emergency medical services dispatch. There were ten fatalities (24%) and 31 survivors. The average age was 31.2 years (range, 1 to 67). Thirty-seven (90%) were men. Eleven persons (27%) were intoxicated (average blood alcohol of 279 mg/dL; range, 140 to 460). Of the 30 survivors transported, hospital records were available for 24. Thirteen were hospitalized and ten underwent surgery. Six major amputations occurred among survivors. Six patients had an Injury Severity Score of more than 15. Three mechanisms of injury occurred: falls on or from a train (56%); pedestrians hit by a train (41%), which accounted for all fatalities; and a train-automobile accident. This is the first comprehensive review of all significant railroad-related injuries in a metropolitan area.

Accidents↗

Use of the emergency department for hypertension screening: a prospective study.

There is controversy as to whether the emergency department is an inappropriate site for screening for hypertensive patients. The pain and apprehension associated with many ED visits have been thought to elevate blood pressure readings falsely in this setting. To resolve this question, all patients admitted to the ED of a university hospital during a one-year period were screened prospectively for hypertension. Follow-up was attempted for patients who, on admission and discharge, had systolic pressures higher than 159 mm Hg or diastolic pressures higher than 94 mm Hg. A total of 239 patients met these criteria, and follow-up was obtained in 45% of the cases. Significant hypertension (systolic greater than 159 mm Hg or diastolic greater than 94 mm Hg) was found in 35% of these patients on follow-up. Borderline hypertension (systolic, 140 to 159 mm Hg; or diastolic, 90 to 94 mm Hg) was documented in 33% of the patients. Thirty-two percent were found to be normotensive when evaluated in a follow-up visit. The number of patients experiencing pain at the time of their initial ED visit was similar among the three groups. Almost half the patients with hypertension on follow-up needed further workup or therapy. The ED can be a useful screening site for hypertension; elevated blood pressure on discharge should ensure referral for follow-up evaluation and therapy.

Adult↗

Combined effect of catheter and tubing size on fluid flow.

Several studies have evaluated the effect of large-bore tubing and various intravenous (IV) catheters on rapid fluid resuscitation. This study combines available equipment, which has been demonstrated to increase IV flow rate, into a system. This system is then compared with one commonly used for IV fluid infusion in hypovolemic patients. The new system requires significantly less (P less than 0.0005) time for both drainage of fluid and changing of IV containers. The improvement in flow rate can be attributed to the use of a rapid inflation/deflation pneumatic pressure device instead of the conventional hand-pumped pressure bag and the decrease in resistance through both the large-bore IV tubing and 12-gauge catheter. The rapid manipulation of IV bags is made possible by the rigid structure and the rapid inflation/deflation ability of the external pump. The possibility of faster change of IV bags and an increase in flow rate make this system a practical tool in the treatment of severely hypovolemic patients.

Catheterization↗

Topical anesthesia for laceration repair: tetracaine versus TAC (tetracaine, adrenaline, and cocaine).

Topical anesthetics have always had a place in anesthetizing mucous membranes. The earliest writing in Greek medical literature makes reference to the use of these topical anesthetizing agents. Previous studies utilized a mixture of tetracaine, Adrenaline, and cocaine in the pediatric population with increased patient compliance. In contrast, another study cites the increased risk of infection in cases where topical anesthetics in combination with potent vasoconstrictors are used. To examine the efficacy and safety of a tetracaine and a tetracaine, Adrenalin, and cocaine mixture (TAC), a randomized, double-blind study was undertaken. A total of 68 patients participated in the study, with 36 receiving TAC and 32 receiving tetracaine. The results indicate that the most efficacious use of TAC is on facial lacerations, regardless of length or depth. Of the 46 participants available for follow-up, one patient in the tetracaine group reported a wound infection. A recommendation of increased use of TAC on facial lacerations, in both the adult and pediatric populations, is made based on the results of this study.

Administration, Topical↗

Survey of undergraduate emergency medical education in the United States.

To determine the status of undergraduate education in emergency medicine, questionnaires were sent to 141 medical schools. Of the 135 schools responding, 15.2% require emergency medicine courses in the fourth year (mean, 164 hours); 11.9% require these courses (average, 84 hours) in the third year. Emergency medicine is offered in 21.8% of second-year and 37.9% of first-year curriculums. Training in cardiopulmonary resuscitation is offered in 96% of the schools responding, and certification is required in 53%. Training in advanced cardiac life support is offered in 73% of schools, with 23% requiring it for graduation. Training in advanced trauma life support is offered in 17.2% of schools. Osteopathic schools require more time for emergency medicine in the clinical years but less time in formal lectures. Schools with a residency program in emergency medicine more frequently offer emergency medicine in the preclinical years. This survey provides some basic data on the status of undergraduate emergency medicine education in medical school curriculums, and it encourages medical educators to review the undergraduate curriculum to ensure that students receive adequate exposure to the essentials of emergency medicine.

Curriculum↗

Core content survey of undergraduate education in emergency medicine.

One hundred forty-one medical schools were surveyed to determine the emergency medicine core content topics and skills being taught in the curricula. Responses were obtained from 96 schools through two mailings and a telephone followup. Most topics surveyed were offered in the vast majority of medical schools (greater than 92%) with the exception of emergency medical services (offered in 79% of schools). Emergency medicine topics were a required part of the curriculum in a much smaller percentage of schools. No subtopics in toxicology, ophthalmologic emergencies, or emergency medical services were required in more than 30% of schools. The survey showed a similar pattern of these skills being offered in most schools, but required in a smaller number. For example, while C-spine immobilization is taught in 90% of schools, it is required in only 46%. Educators must consider a coherent, interdisciplinary knowledge base and skills list for their medical school curricula.

Clinical Competence↗

An analysis of medical care at mass gatherings.

Emergency medical care at public gatherings is haphazard at best and dangerous at worst. The Arizona chapter of the American College of Emergency Physicians, through the Chapter Grant Program, studied the level of medical care provided at public gatherings in order to develop guidelines for emergency medical care at mass gatherings. The study consisted of a survey of medical care at 15 facilities providing events for the public. The results of these surveys showed a wide variation of medical care provided at mass events. Of the 490 medical encounters reviewed, 52.2% were within the realm of care of paramedics, but not basic emergency medical technicians. The most common injuries/illnesses were lacerations, sprains, headaches, and syncope. Problems noted included poor documentation and record keeping of medical encounters, a tendency for prehospital care personnel to make medical evaluations without transport or medical control, and variability of care provided. Based on this survey and a literature review, guidelines for medical care at mass gatherings in Arizona were determined using an objective-oriented approach. It is our position that event organizers have the responsibility of ensuring the availability of emergency medical services for spectators and participants. We recommend that state chapters or National ACEP evaluate the role of emergency medical care at mass gatherings.

Arizona↗

Intraosseous infusions: a usable technique.

Intraosseous infusions were widely used in pediatric patients during the 1930s and 1940s. Recent reports have re-introduced this concept and confirmed its safety and ready accessability for fluid and drug administration. However, these reports have not addressed the difficulties encountered during insertion of the intraosseous needle. Spinal needles, standard metal intravenous (IV) needles, and bone marrow biopsy needles have been suggested for intraosseous infusion. These needles were tested for ease of insertion on a pediatric cadaver leg. The site for needle placement was also evaluated during the study. It was found that the 13-gauge Kormed/Jamshidi disposable bone marrow/aspiration needle was the easiest to insert and did not plug with bone or tissue during insertion. An area proximal to the medial malleolus was found to provide a stable, relatively flat, and easily penetrable location for needle placement. This method was successfully utilized in ten pediatric and five adult patients. Intraosseous needle placement is a safe, rapid method to gain access to the venous circulation. By utilizing these techniques, a stable, usable fluid line can be established in even the most dehydrated pediatric patients.

Bone Marrow↗

Pressurization of i.v. bags: a new configuration and evaluation for use.

External pressure devices are often utilized to increase the flow rates of IV fluids in exsanguinating patients. However, increasing the flow rate by this method also increases the rate at which IV bags need changing. Time is lost and valuable personnel are preoccupied in maintaining the numerous hand-pumped external pressure devices and IV bags. A systematic evaluation comparing the hand-pumped device with a new, pneumatic external pressure device (Infusor-1, Medical Innovations, Inc., Phoenix, AZ) is presented. A new multiunit configuration (Infusor-Rack) for the pneumatic device is also described. We found a significant decrease in IV bag take-down/setup time with the new pneumatic pressure device. This system is faster, more reliable, and easier to use than the standard hand-pumped pressure bag and should be viewed as a practical improvement in the fluid delivery system.

Equipment Design↗

Usefulness of abdominal flat plate radiographs in patients with suspected ureteral calculi.

A total of 120 plain abdominal radiographs (PARs) from intravenous pyelograms (IVPs) were presented without patient history in a random manner to a staff radiologist and staff emergency physician (EP). Scout films were used as the PAR to minimize calculus movement. Each reader examined each film for the presence of ureteral calculi. The readers localized all calculi and rated the likelihood of their presence. Fifty-one PARs from IVPs demonstrated ureteral calculus disease; 40 of these films demonstrated 41 radiopaque calculi, while 11 films demonstrated obstruction without radiopaque calculi. These readings were then matched to the known IVP results. Together the readers were correct on 50% of the predictions (radiologist, 51%; EP, 48%). The EP and the radiologist had similarly correct percentages on PARs from positive IVPs (33% and 36%, respectively) and on PARs from negative IVPs (60% and 64%). True-positive (33% and 25%), true-negative (76% and 71%), false-positive (27% and 35%), and false-negative (36% and 55%) rates were constructed for the radiologist and EP, respectively. Our study demonstrates that PARs are unreliable and do not appear to add useful information in the evaluation of suspected ureteral colic.

Diagnostic Errors↗