Search

Background: Significant changes in cardiac preload and afterload are generated by a number of factors present during the operation of high performance aircraft. These include high levels of +Gz, positive pressure breathing and anti-G straining maneuvers. Centrifuge subjects are exposed to these same factors in doses that are comparable to their operational counterparts. The question of whether such exposures produce long-term adverse effects on the heart has not been definitively answered., Methods: In an effort to further address this issue, a longitudinal study was conducted on 18 newly recruited centrifuge panel members (7 males and 11 females) who did not have a previous history of significant high +Gz exposure. In order to document the cumulative long-term effects of high +Gz exposure and G protection measures, baseline echocardiographic studies were conducted prior to any +Gz exposure on the Dynamic Environment Simulator (DES) centrifuge. The echocardiograms were repeated after each panel member completed eight sessions of indoctrination. These follow-up echos were performed after all 18 subjects had been exposed to over 45 min (cumulative) of sustained acceleration > or = 2 G. Each subject served as his/her own control. All studies were evaluated independently by a cardiologist who was blinded to the order in which the studies were performed. Although complete echocardiographic studies were performed, only the parameters identified as significant in prior studies were evaluated., Results: No significant differences were found between the initial and follow-up echo parameters. No significant differences were found between male and female responses., Conclusions: We found no significant differences in cardiac function after 45 min (cumulative) of exposure to G > or = 2 in men or women. These subjects will be monitored during a longitudinal study throughout their centrifuge subject career.

Fifty boys, hospitalized on a school-age and an adolescent unit in an intermediate length psychiatric hospital, were studied while off psychoactive medication to determine how serum dopamine beta hydroxylase (DBH) activity varies with different childhood maltreatment experiences. Childhood maltreatment was categorized according to onset (before 36 months old, between 36-72 months old and over 72 months old). Childhood maltreatment groups were compared with a group of psychiatrically hospitalized boys who had neither been abused nor neglected. Boys who were younger than 72 months at age of onset of maltreatment had significantly lower DBH activity than those who had experienced maltreatment later in childhood and those who had not been subjected to abuse or neglect. This difference appeared attributable to the DBH activity of school age (but not adolescent) boys who had been abused/neglected before 72 months. Boys with a principal diagnosis of conduct disorder solitary aggressive type had lower DBH activity than boys without this diagnosis regardless of whether or not they had been maltreated. Low serum DBH may be a biological sequela of maltreatment early in life that correlates with the development of conduct disorder solitary aggressive type in boys.

The process of evaluating the performance of medical students and/or residents during emergency medicine clinical rotations is constrained by several potential shortcomings. These constraints can limit the quality of the information provided to the student/resident, as well as that provided to the sponsoring institution. During the course of an academic year at United States Air Force Medical Center, Wright-Patterson, a number of medical students, interns, and residents rotate through the emergency department. The limitations identified in the process of evaluating these trainees include the (1) retrospective nature of the data provided in evaluations; (2) the lack of clear pre-established performance criteria; (3) the time constraints placed on preceptors; and (4) the incremental nature of the observations of performance during emergency medicine rotations. The evaluation tool developed to address these limitations is presented as a mechanism to help improve the ability of educators to evaluate and record performance during emergency medicine rotations.

In April 1989, we initiated a test program to evaluate the use of semi-automated external defibrillators in five United States Air Force Medical Treatment Facilities. The objectives of the study were 2-fold. First, the feasibility of conducting a uniform training program in a number of geographically separated basic life support emergency medical services (EMS) systems was assessed. The second objective was evaluation of psychomotor skills maintenance by Air Force Emergency Department emergency medical technicians (EMTs) in simulated resuscitations 6 months after initial training. Performance was evaluated in each of six areas for the 48 EMTs completing retesting. Forty-three of the 48 EMTs were assessed to have properly completed the resuscitations. Three of the remaining five failed to clear prior to defibrillating, and in two cases the delivery of three defibrillatory shocks was delayed for 6-8 minutes from the time of arrival at the patient's side. These results demonstrate the feasibility of providing training and maintaining proficiency in military EMS systems.

Twenty-one psychiatrically hospitalized boys were studied while off psychoactive medication to determine if conduct disorder, solitary type, and abuse or neglect experiences correlated with low levels of dopamine-beta-hydroxylase (DBH) activity. Preliminary results supported earlier findings that undersocialized types of conduct disorder in boys were correlated with low DBH activity. Possible or definite neglect or abuse before 36 months of age was correlated with low DBH activity. Abuse or neglect was not correlated with low DBH activity when time of occurrence was not specified. Low serum DBH may be a biological sequela of seriously disrupted attachment.

We reviewed the cases of 30 patients presenting to the emergency department over a four-month period with a total of 31 injuries suffered while riding a mechanical bull. The majority of injuries were sprains and contusions. The most severe injuries included seven fractures, one dislocation, and one fracture-dislocation. Three patients required hospitalization, including one with a compression fracture of C7. The majority (74%) of injuries involved the upper extremities.

Effective treatment of cyanide poisoning requires rapid diagnosis, good supportive treatment and the use of a specific antidote. The currently available antidotes offer demonstrated efficacy along with significant potential adverse side effects. We have investigated an alternate approach to antidote therapy for cyanide poisoning by using Stroma-Free Methemoglobin Solution ( SFMS ). Rats injected with an LD100 intravenous dose of cyanide were treated with SFMS equal to 1.5% of their total body hemoglobin. There was a highly significant increase in the survival rate of the treated group compared to saline controls. The potential advantages of SFMS over current antidotes include an immediate onset of action, rapid elimination of cyanide from the body and a mode of action that doesn't compromise any of the patients' oxygen carrying capacity. SFMS shows promise as a significant adjunct in the treatment of cyanide poisoning.

In recent years, the increasing use of laetrile has been added to the traditional sources of exposure to cyanide in industry, chemistry labs, and fumigation. The events in Jonestown in 1978 were a grim reminder of the lethality of cyanide. Nonetheless, advancement in new modes of treatment has been slow. The traditional method of treatment used in the United States is effective, but not without its own morbidity and mortality. Using two case reports as models, we review here the topic of cyanide poisoning including sources of exposure, pathophysiology, clinical manifestations of both acute and chronic exposure, and modes of treatment. Although there is currently no accepted alternate treatment in this country, review of the literature shows promise in other modalities being investigated in Europe, including hydroxocobalamin, cobalt salts, and particularly aminophenols.

Several aspects of stroma-free methemoglobin solution (SFMS) as a cyanide antidote were investigated using a rat model. Stroma-free methemoglobin solution was more than 90% effective against multiples of the LD90 of cyanide up to and including four times the LD90 and approximately 50% effective against multiples up to and including eight times the LD90. Highly concentrated solutions of SFMS (33 g/dl) did not differ significantly from less concentrated solutions of SFMS (16 g/dl) when compared on the basis of efficacy. Administration of large doses of SFMS alone resulted in no apparent morbidity or mortality. It could be that SFMS is a safe and effective alternative antidote for the treatment of cyanide poisoning.

On September 12, 1979, Hurricane Frederic struck the Gulf Coasts of Mississippi and Alabama. A retrospective review of emergency department logs for a three-week period surrounding the storm was conducted to determine the amount and type of back up needed for an emergency department to cope with the results of such a disaster. There was a significant increase in the number of patients presenting to the emergency department for at least two weeks after the storm, with the greatest demand being for professionals skilled in outpatient trauma management. The nature of hurricanes is discussed, as are specific items to be considered in disaster planning for areas subjected to these storms.

Two methods for modifying standard orotracheal intubation models, in order to teach and practice special airway management skills, are described. Using these quick and inexpensive manipulations, an intubation manikin can be modified for use as a teaching model for standard nasotracheal intubation techniques as well as both orotracheal and nasotracheal intubation with a lighted stylet.

The standard nitrite/thiosulfate regimen for cyanide poisoning was tested in our rat model. By modifying the treatment regimen and the nitrite solution an effective antidote against an LD90 of cyanide could be produced. However, this treatment was effective against two times the LD90 only when administered ten minutes prior to cyanide injection. These results are in marked contrast to our results with stroma-free methemoglobin solutions (SFMS) which showed SFMS to be a highly effective antidote against four times the LD90 when administered 30 seconds after an intravenous injection of cyanide. SFMS proved to be an effective antidote for two times the LD90 when administered up to sixty seconds after the cessation of respiration.

The triage process is a valid concept in the initial approach to multiple casualties. Triage tags are, in theory, a reasonable adjunct to the process, but have proved to be a failure in practice. Based on the historical perspective and on the authors' experience with approximately 180 mass casualty drills and incidents, it is recommended that the "daily routine doctrine" be applied and that conventional, color-coded triage tags be replaced by a process of "geographical triage." A valid model for disaster planning is needed, and organizers must conduct drills that are based on the actual threat to the community in order to determine the most efficacious way to manage medical response.

Three experiments were conducted to investigate the theoretical reduction of rate and duration of reinforcement to their product, rate of reinforcement-time, under concurrent chain schedules. In Exp. I, rate of reinforcement-time was varied by varying rate of reinforcement delivery, holding duration of reinforcement availability constant; in Exp. II, rate of reinforcement-time was varied by holding rate of reinforcement delivery constant and varying duration of reinforcement availability; in Exp. III, rate of reinforcement-time was held constant by varying both rate and duration of reinforcement simultaneously and inversely. For all three experiments, both relative rate of responding and relative time spent in the initial link were found to match approximately the relative rate of reinforcement-time arranged in the terminal link. These data were interpreted as support for the notion that rate and duration of reinforcement may be functionally equivalent and reducible to a single variable, rate of reinforcement-time.