Using spectral reflectance to distinguish between tracheal and oesophageal tissue: applications for airway management.

Proper placement of the tracheal tube requires confirmation, and the predominant method in addition to clinical signs is the presence of end-tidal carbon dioxide. Such is the importance of confirmation that novel methods may also have a place. We previously demonstrated using ex-vivo swine tissue a unique spectral reflectance characteristic of tracheal tissue that differs from oesophageal tissue. We hypothesised that this characteristic would be present in living swine tissue and human cadavers. Reflectance spectra in the range 500-650 nm were captured using a customised fibreoptic probe, compact spectrometer and white light source from both the trachea and the oesophagus in anesthetised living swine and in human cadavers. A tracheal detection algorithm using ratio comparisons of reflectance was developed. The existence of the unique tracheal characteristic in both in-vivo swine and cadaver models was confirmed (p < 0.0001 for all comparisons between tracheal and oesophageal tissue at all target wavelengths in both species). Furthermore, our proposed tracheal detection algorithm exhibited a 100% positive predictive value in both models. This has potential utility for incorporation into airway management devices.

Medic for the millennium: the U.S. Army 91W health care specialist.

The new millennium challenges the Army Medical Department to provide good care in a variety of circumstances from peacetime to operations other than war to combat. To provide care in this broad variety of missions, the Army Medical Department needs flexible providers. The new 91W health care specialist enlisted medic is designed to meet this need. By coupling skills in emergency care, evacuation, medical force protection, and primary care with certification in emergency medical technology, the 91W initiative will fill the needs of the Army now and into the new millennium.

U.S. Army MEDEVAC in the new millennium: a medical perspective.

The U.S. Army Aeromedical Evacuation community (MEDEVAC) possesses a long-standing tradition of excellence in the care and transportation of combat casualties. Recent developments in civilian air medical transport and quantitative review of MEDEVAC operations have identified potential areas for improvement, concentrating on enhanced flight medic standards, training, sustainment and medical oversight of the air ambulance system. These proposed changes are discussed in detail, from the perspective of current emergency medicine and aviation medicine standards of practice. If instituted, these changes would facilitate the emergence of a true air medical transport capability comparable with the civilian community standard.

U.S. Army air ambulance operations in El Paso, Texas: a descriptive study and system review.

OBJECTIVES: To analyze a high-volume military air ambulance unit and review the U.S. Army air medical transport system and Military Assistance to Safety and Traffic (MAST) program. METHODS: The setting was a remote medical system with numerous ground emergency medical services. All patients transported between January 1, 1996, and February 28, 1998, were included. Patients who were dead on scene or for whom records were unavailable were excluded. A retrospective review of transport and available inpatient records was conducted. RESULTS: Five hundred seventeen patients were transported during the study period; 461 patients met inclusion criteria (89%). Of these, 70% were classified as trauma; 30% possessed medical or other surgical diagnoses. Prehospital responses numbered 71.6%, while 28.4% were interhospital transfers. Missions averaged 23.4 minutes per flight, with no major aircraft mishaps. Prehospital utilization review showed appropriate use; 35% of interhospital trauma and 11% of interhospital nontrauma missions were staffed inadequately by these criteria. Time intervals, procedures, and program impact are discussed. CONCLUSION: This and similar units participating in the MAST program provide effective air transport in settings underserved by civilian programs. Quality and wartime readiness could be improved by centralized medical direction, treatment and transfer protocols, and enhanced training of medics. Further investigations of the clinical impact of advanced training and a two-medic aircrew model are warranted.

Mass casualty triage knowledge of military medical personnel.

During battlefield and mass casualty incidents, triage has been traditionally performed by many different personnel, including medics, nurses, dentists, and physicians. The objective of this study was to determine which military medical providers are most knowledgeable in mass casualty triage. The design was a prospective, written, timed, case-based examination of triage knowledge. Participants were volunteers from the active duty medical (physician), dental, nursing, and enlisted corps of the three military services. Subjects completed a 16-minute written examination consisting of seven cases in each of three simulated mass casualty scenarios: combat; nuclear, biological, and chemical; and humanitarian. Tests were taken anonymously, although demographic data on medical specialty, training, and experience were collected. Participants were instructed to classify the cases using the NATO categories of immediate, delayed, minimal, or expectant. Scores were tabulated according to two grading scales: an absolute scale of number correct, and a weighted scale amplifying gross misclassifications. Median scores between groups were tested pairwise using the Kruskal-Wallis one-way analysis of variance with p < or = 0.05. Statistically significant differences were noted between the highest and lowest scoring groups in each scenario. Our conclusion is that among the subject groups tested, physicians were best at mass casualty triage. Dentists, nurses, and medics scored progressively less well on our examination.

Army aeromedical crash rates.

BACKGROUND: Safety is a principal concern for everyone in aviation, including those in military and civilian aeromedical programs. The U.S. Army flies thousands of helicopter missions each year, including many aeromedical flights. The comparison between Army general and aeromedical aviation crash data provides a benchmark for establishing patterns in aeromedical safety and may be useful for similar programs examining safety profiles. OBJECTIVES: To determine the crash rates of Army aeromedical rotary-wing (helicopter) programs and compare them with crash rates in Army general aviation. METHODS: Retrospective review of safety data from 1987 to 1995. Crashes or mishaps are categorized into three classes: A, B, and C. Class A reflects the most serious mishap and involves loss of life or aircraft destruction, whereas classes B and C represent lesser but still significant mishaps. Crash rates are compared on a year-by-year basis and are reported as events per 100,000 flight hours. Statistical analysis was performed by the z test with Yates' correction, with significance set at p < or = 0.05. RESULTS: During the study period, 13.31 million total flight hours were recorded, with 741,000 aeromedical hours logged. The mean Army general aviation class A crash rate was 1.86 compared with the aeromedical rate of 2.02. The mean general class A to C crash rate was 7.37 compared with the aeromedical rate of 7.44. Between 1992 and 1995, there were 3 years when the Army aeromedical program suffered no class A mishaps. Differences between study groups are statistically significant, but they are interpreted conservatively given the very low incidence of mishaps in both groups. Both rates are comparable with published civilian mishap rates. CONCLUSIONS: There is a very low overall incidence of crashes in both groups. There may be no practical difference between Army general and aeromedical aviation mishap rates. Furthermore, Army crash rates are comparable with published civilian mishap rates.

EMS systems: foundations for the future.

Emergency medical services (EMS) occupy a unique position in the continuum of emergency health care delivery. The role of EMS personnel is expanding beyond their traditional identity as out-of-hospital care providers, to include participation and active leadership in EMS administration, education, and research. With these roles come new challenges, as well as new responsibilities. This paper was developed by the SAEM EMS Task Force and provides a discussion of these new concepts as well as recommendations for the specialty of emergency medicine to foster the continued development of all of the potentials of EMS.

Improving combat casualty care and field medicine: focus on the military medic.

As military medicine in general copes with a rapidly changing world environment, so too must the backbone of the medical force, the enlisted medic. To meet these challenges, the training and utilization of military medics must match new and different missions. This paper will explore innovative approaches to training and preparing for combat casualty care and field medicine. The focus will fall on the education, evaluation, operations, patient-care skills, equipment, and telemedicine potential of the military medic. Future directions for study and development will be suggested. Exploration of the following may improve the capability of the military medic: (1) improved training to include advanced-level skills and interventions for combat casualty care and broader exposure to the casualties expected in operations other than war; (2) annual educational and periodic proficiency evaluation requirements; (3) strengthened medical control at all echelons; and (4) carefully selected additional equipment and technologies to enhance medical capabilities.

Military and civilian emergency aeromedical services: common goals and different approaches.

Military and civilian organizations in the U.S. operate separate but parallel emergency aeromedical services. Despite common origins, military and civilian approaches and methods have diverged. This article compares and contrasts the capabilities, priorities, safety, equipment, training and personnel of the largest military service, the U.S. Army, to civilian rotary wing (helicopter) emergency aeromedical programs. The different successes of military and civilian emergency aeromedical programs can be considered for use to improve the services of each. In general, Army programs operate larger aircraft and utilize two pilots per aircraft. Safety is a high priority and the Army aeromedical safety record is excellent. The Army also places a high degree of emphasis on crashworthiness and protective gear for the crew. Most civilian air Emergency Medical Service (EMS) programs operate small to moderate-sized aircraft flying with a single pilot. The recent safety record has improved dramatically. Civilian programs may add to their safety by considering two pilots and incorporating the crashworthy and protective advancements made by the military. Civilian programs fly with two highly trained medical technicians, nurses or physicians, equipped with state-of-the-art medical equipment. Army helicopters fly with one lesser-trained medical crewmember and less equipment. Improved combat casualty care and battlefield survival may be possible by increasing both the number and training of the medical attendants on Army aircraft.

Mass gathering medicine: a review.

The provision for emergency medical care for spectators and participants at large events is a growing area of interest. This article describes the definition and characteristics of medical care at mass gatherings. The literature is reviewed with regard to the planning, organization, personnel, and staffing required at these events. The equipment and transportation assets needed are also discussed. Disaster and mass casualty planning implications also are described.

Optimal positioning for cervical immobilization.

STUDY OBJECTIVE: We hypothesized that optimal positioning of the head and neck to protect the spinal cord during cervical spine immobilization can be determined with reference to external landmarks. In this study we sought to determine the optimal position for cervical spine immobilization using magnetic resonance imaging (MRI) and to define this optimal position in a clinically reproducible fashion. METHODS: Our subjects were 19 healthy adult volunteers (11 women, 8 men). In each, we positioned the head to produce various degrees of neck flexion and extension. This positioning was followed by quantitative MRI of the cervical spine. RESULTS: The mean ratio of spinal canal and spinal cord cross-sectional areas was smallest at C6 but exceeded 2.0 at all levels from C2 to T1 (P < .05). At the C5 and C6 levels, the maximal area ratio was most consistently obtained with slight flexion (cervical-thoracic angle of 14 degrees) (P < .05). For a patient lying flat on a backboard, this corresponds to raising the occiput 2 cm. More extreme flexion or extension produced variable results. CONCLUSION: In healthy adults, a slight degree of flexion equivalent to 2 cm of occiput elevation produces a favorable increase in spinal canal/spinal cord ration at levels C5 and C6, a region of frequent unstable spine injuries.

A review of spinal immobilization techniques.

Immobilization of the spine is an important skill for all emergency providers. This article reviews the literature regarding the equipment, adjuncts, and techniques involved in spinal immobilization. Current prehospital practice is to apply spinal immobilization liberally in cases of suspected neck or back injury. Rigid cervical collars, long backboards, and straps remain the standard implements for immobilizing supine patients. Tape, foam blocks, and towels can complement the basic items and improve stability. Padding may improve positioning and comfort. Intermediate-stage devices include the short backboard and newer commercial devices. Properly used, all provide reasonable immobilization of the sitting patient. Future directions for study include refinement of optimal body position, dynamic performance of all devices, and broadening study populations to include children and the elderly.

Lessons in emergency evacuation from the Miamisburg train derailment.

Hazardous materials incidents result from the release of materials considered to be harmful or potentially harmful to human beings or the environment. This article describes a train derailment and subsequent hazardous materials release with the evacuation of approximately 50,000 citizens. The hazardous materials release took five days to control and resulted in 561 patient visits to local emergency departments for symptoms related to chemical exposure. The evacuation and emergency medical operations are described and serve as a model for developing community emergency preparedness plans and managing victims involved in hazardous materials incidents.

On the ground at the U.S. Air Show.

Careful planning and organization at mass gatherings are essential if adequate medical care is to be ensured. The U.S. Air Show in Dayton, Ohio, attracts thousands of spectators annually and requires that dozens of EMS agencies and hundreds of first responders, EMTs, paramedics, nurses and physicians join forces to provide EMS coverage.

A proposed model for a residency experience in mass gathering medicine: the United States Air Show.

STUDY OBJECTIVE: Mass gathering medicine is an increasingly important responsibility for emergency physicians. A formal experience in mass gathering medicine can introduce emergency medicine residents to this aspect of community medicine. DESIGN: Educational model based on field experience and retrospective chart review from 1981 through 1991. SETTING: The US Air Show is a summer event that attracts an average of 223,000 spectators annually. Medical care is provided by physicians, nurses, and technicians operating within an organized system of care. Emergency medicine resident physicians (first-, second-, and third-year) evaluate and treat patients appropriate for the resident's level of responsibility. Residents provide immediate medical control and are integrated into the event disaster plan. On-site attending physician supervision is available at all times. Didactic instruction and event orientation are integrated into the residency curriculum. Residents participate in the planning stages of the event. RESULTS: During the study period, 2,091 patients were seen. The most common presenting problems were heat illness (28%), blisters and scrapes (25%), headaches (23%), fractures and lacerations (9%), and eye injuries (5%). One hundred forty-eight patients (7%) required transportation to the hospital. Approximately 16 residents participate each year and treat an average of 13.7 patients during their four-hour shift. A resident training model for a mass gathering experience is proposed to include adequate crowd size to generate useful patient volumes; a regularly scheduled event; organized medical and disaster preparations meeting local or published standards; didactic instruction on history, principles, and current issues; on-site attending supervision; degree of responsibility appropriate for training level; participation in planning and organizing the event; and postevent debriefing. CONCLUSION: A residency experience and training program in mass gathering medicine can introduce the principles of planning and providing care for crowds attending large public events.

Prehospital misidentification of tachydysrhythmias: a report of five cases.

Identification and treatment of tachydysrhythmias is an important element of prehospital care. Five cases of prehospital misidentification of tachydysrhythmias are presented to highlight the challenges and pitfalls of field management. The literature is reviewed and discussed in light of new therapies and technology. Guidelines for patient subgroups potentially benefitting from on-line medical control and biotelemetry are explored.