Portable ultrasound in disaster triage: a focused review

Ultrasound technology has become ubiquitous in modern medicine. Its applications span the assessment of life-threatening trauma or hemodynamic conditions, to elective procedures such as image-guided peripheral nerve blocks. Sonographers have utilized ultrasound techniques in the pre-hospital setting, emergency departments, operating rooms, intensive care units, outpatient clinics, as well as during mass casualty and disaster management. Currently available ultrasound devices are more affordable, portable, and feature user-friendly interfaces, making them well suited for use in the demanding situation of a mass casualty incident (MCI) or disaster triage. We have reviewed the existing literature regarding the application of sonology in MCI and disaster scenarios, focusing on the most promising and practical ultrasound-based paradigms applicable in these settings.

Aeromedical trauma sonography by flight crews with a miniature ultrasound unit

BACKGROUND

While ultrasound has become an established diagnostic modality in trauma care, no study has evaluated its use in the prehospital setting.

OBJECTIVE

To examine the use of the focused abdominal sonography for trauma (FAST) exam in the prehospital setting.

METHODS

After a three-hour training session in the FAST exam, the nonphysician flight team of an emergency medical services (EMS) helicopter program attempted a FAST exam on trauma patients to determine the feasibility of such an intervention.

RESULTS

The majority (83%) of the 71 patients entered suffered blunt trauma. FAST exams could not be performed in 34 patients (48%) due to insufficient time (67%), inadequate patient access, or combativeness. Technical difficulties (difficult screen visualization due to ambient lighting, battery failure, and machine malfunction) prevented scanning in seven (19%) of the 37 in whom it was attempted. In those in whom scanning was successful, the pelvic view was most commonly obtained followed by the right upper quadrant (RUQ) and left upper quadrant (LUQ).

CONCLUSION

Significant advances in training, technology, and/or patient access will be necessary for aeromedical FAST to be feasible.

Ultrasound interpretation of hydronephrosis is improved by a brief educational intervention

Nineteen emergency medicine (EM) physicians (14 residents and 3 attendings) from an EM residency program which teaches ultrasound as part of the curriculum, were asked to rate 40 ultrasound scans showing different degrees of kidney hydronephrosis, first solely on the basis of their prior knowledge and experience. One week later, after a brief 15 minute lecture on a new objective method to read degrees of hydronephrosis, the same EM physicians were again asked to rate the 40 ultrasounds. One month later, to assess retention of the method, the same physicians were asked to read the same scans using the objective method presented 1 month prior. The three readings were compared with each other, and then each with a gold standard established for the study. Agreement of the group regarding scan interpretation improved and was maintained after the educational intervention (multirater kappa + .19, .32, and .32 for the three tests administered). When the differences between each week's readings and the gold standard were assessed, differences decreased with each successive test, and were statistically significant with the third test (P = .029). We conclude that our brief educational intervention improves agreement among physicians in readings of ultrasound scans and also significantly increases accuracy in readings when compared with a gold standard.

The focused abdominal sonography for trauma (FAST) examination: considerations and recommendations for training physicians in the use of a new clinical tool

Focused abdominal sonography for trauma (FAST) is being used by growing numbers of emergency physicians and surgeons because it has proven to be an accurate, rapid, and repeatable bedside test for evaluating abdominal trauma victims. Controversy exists about the optimal means of FAST education and the number of examinations necessary to demonstrate competency. Most FAST educators agree that FAST education should consist of three phases: didactic, practical, and experiential. This article summarizes options and preliminary recommendations suitable for developing a FAST curriculum.

EMS provider reluctance to perform mouth-to-mouth resuscitation

OBJECTIVES

To assess the willingness of EMS providers to perform mouth-to-mouth resuscitation (MMR) both with and without a barrier device (e.g., face shield), while not on duty; and to determine the providers' perceived risk from performing MMR and the frequency with which they carry a barrier device.

METHODS

A survey was mailed to 543 EMS providers presenting four scenarios describing a patient in respiratory arrest. The respondents were asked whether they would perform MMR in each scenario both with and without a barrier device.

RESULTS

Of those surveyed, 342 (64%) responded. Strikingly few (< or =5%) of the respondents would perform MMR without a barrier on each of the cases, except for the case of a pediatric drowning (52%). The respondents were least likely to perform MMR on a patient with AIDS (< 1%). The respondents were much more likely to perform MMR in each case if a barrier device was available. The respondents were very concerned about the risk of contagion from MMR, yet 44% of the respondents rarely or never carried a barrier device with them.

CONCLUSION

Emergency medical services providers are quite reluctant to perform MMR, and this is likely related to their perception of a high risk of contagion. The availability of barrier devices greatly decreases this reluctance, but EMS personnel carry such devices infrequently.

Rapid oral hydration results in hydronephrosis as demonstrated by bedside ultrasound

STUDY OBJECTIVE

To determine whether vigorous oral hydration (20 mL/kg) causes hydronephrosis as determined by bedside ultrasound.

METHODS

We conducted a prospective laboratory trial in 35 healthy volunteers weighing less than 90 kg and between the ages of 18 and 50 years. The right kidney of the volunteers was scanned by emergency physicians at time 0 both before and after voiding, and the volunteers then drank 20 mL/kg of bottled water. The kidney was scanned in the transverse and sagittal planes both before and after voiding at 60 and 90 minutes after completion of the water load. The scans were interpreted by a physician trained and credentialed in emergency ultrasound, blinded to the volunteers' identity, the time of the scan, and the volume of urine voided by the subject. Images were rated as to the degree of hydronephrosis according to literature-established criteria, as follows: grade 0=no hydronephrosis, grade 1=mild, grade 2=moderate, and grade 3=severe hydronephrosis.

RESULTS

Hydronephrosis was present in 3 (8.6%) of the 35 subjects at time 0 (prehydration), 24 (68.6%) at 60 minutes, and 20 (57.1%) at 90 minutes. Overall, hydronephrosis occurred at least once in 28 (80%) of the 35 subjects after oral hydration compared with 3 (8.6%) of the 35 subjects before hydration. Hydronephrosis was found to be significantly related to forced hydration for all posthydration times (60 minutes, 90 minutes, and 60+90 minutes combined) versus prehydration time 0 (P <.001).

CONCLUSION

Without prior fluid intake, even mild degrees of hydronephrosis were relatively uncommon, and seen in only 8.6% of study patients. In the presence of vigorous oral hydration, however, mild or moderate hydronephrosis is a frequent occurrence seen at least once in 80% of our study of healthy volunteers after hydration. Caution is warranted in this setting when interpreting mild or moderate hydronephrosis found on bedside ultrasound by emergency physicians.

Does wearing a necktie influence patient perceptions of emergency department care?

We conducted a prospective study of discharged emergency department (ED) patients to determine the effect of wearing a necktie by emergency physicians (EPs) had on patients' impression of their medical care. All male EPs were assigned randomly by dates to wear a necktie or no necktie, and the attire worn was otherwise similar in all respects. The study was conducted at a community teaching hospital with an Emergency Medicine residency and an annual census of 40,000. A total of 316 patients were surveyed. There were no statistically significant differences between patient groups in any of the five areas surveyed, including patient perception of physicians' appearance. Nearly 30% of patients incorrectly identified their doctor as wearing a necktie when no necktie was worn, and the perception of tie wearing was correlated with a positive impression of physician appearance. Wearing or not wearing a necktie did not significantly affect patients' impression of their physician or the care they received. However, patients seemingly preferred the appearance of physicians who were perceived to wear neckties.

Nebulized glucagon in the treatment of bronchospasm in asthmatic patients

This study sought to determine if nebulized glucagon, a well-known smooth muscle relaxant, is effective in relieving asthmatic bronchospasm. Ten subjects, aged 12 to 26 years, with chronic stable asthma were studied in a pulmonary function laboratory under a randomized double-blind, placebo-controlled, crossover design. Bronchospasm was induced in each subject with progressive doses of nebulized methacholine until forced expiratory volume in 1 second (FEV1) had decreased at least 20% from baseline. Subjects then received either nebulized saline or 2 mg of nebulized glucagon. Spirometry was performed at 5, 15, and 30 minutes after treatment. Subjects then received 2.5 mg of nebulized albuterol and had spirometry 15 and 30 minutes thereafter. Each subject returned for testing with the alternative solution at least 1 week later. Treatment with nebulized glucagon resulted in a 58% +/- 15% improvement in FEV1 15 minutes after treatment compared with 36% +/- 7% after nebulized saline (P < .05). No adverse effects of glucagon treatment occurred. This study suggests that nebulized glucagon reduces methacholine-induced bronchospasm in asthmatic patients.

Impact of emergency medicine residents on ancillary test utilization

The effect of the addition of emergency medicine residency on the use of ancillary testing in a teaching hospital's emergency department (ED) staffed previously by emergency medicine board-certified physicians was studied. Prospectively, the utilization of three common ancillary tests (electrolyte levels, X-ray, or electrocardiogram) for four common chief complaints of patients eventually discharged from the ED was evaluated. A 12-month period before and a 15-month period after introduction of an emergency medicine residency program were compared. The mean number of ancillary tests utilized by the ED attending physicians working with residents was compared with the mean number of tests generated by the same physicians (all emergency medicine board-certified) for the same complaints in the year before the residents' arrival. There was no significant difference in test use before and after introduction of the residency (P = .66). Faculty use of tests was also unaffected by the concurrent presence of residents (P = .068). These results show that the use of testing for a sample of common ED complaints was not affected by the introduction of emergency medicine residents to a previously emergency medicine board-certified staff in one community teaching hospital.

The emerging role of bedside ultrasonography in trauma care

Ultrasonography has emerged as a primary imaging modality in the evaluation of the trauma victim. Both emergency physicians and surgeons have been proven capable of performing this rapid, noninvasive evaluation of the chest and abdomen. This article describes the trauma ultrasound examination and illustrates how bedside ultrasonography can be incorporated into routine trauma care.

Applications for ultrasonography in the emergency department

The primary emergency applications of diagnostic ultrasonography are now reasonably well defined. Basic characteristics of the emergency department examination, including its rapid and highly focused nature, determine both the limitations and advantages of this technique. As greater experience and more advanced technologies develop in the emergency department setting, the role of ultrasonography will likely expand into areas that are not generally practiced today. Doppler technology, especially, promises to provide the emergency department physician of the future an even more powerful tool for the rapid diagnosis of a variety of common and critical conditions.

Transnasal butorphanol in the emergency department management of migraine headache

Transnasal butorphanol (TNB) is a mixed agonist-antagonist opioid that has recently been released for the treatment of painful conditions. Patients with a history of migraine diagnosed in either of two emergency departments (EDs) with a moderate or severe migraine were eligible for this prospective study. Patients received 1 mg of TNB at time zero and again in 45 minutes if needed. Twenty-five patients were studied. Pain intensity was measured on a 10-cm visual analog scale. Mean pain intensity was significantly decreased at 15 minutes and declined from 7.9 +/- 1 cm initially to 2.5 +/- 3.3 cm at 90 minutes. Sixty percent of the patients required no further treatment. Thirty-six percent experienced side effects, with all but 1 being mild or moderate. Seventy-five percent rated the treatment as good, very good, or excellent, and 71% would prefer to receive TNB for future migraines over other treatment options. TNB offers rapid, effective pain relief to the majority of ED migraine patients.

Deep vein thrombosis, pulmonary embolism, and the white clot syndrome

Thromboembolic events such as deep vein thrombosis (DVT) and pulmonary embolism (PE) are very uncommon in the pediatric age group; even more rare is the white clot syndrome. We present the case of a 13-year-old girl who presented with no known risk factors for thromboembolic disease or cardiopulmonary complaints, yet was found to have extensive lower extremity DVT and PE. This patient also suffered the rare but potentially devastating complication of heparin therapy referred to as the white clot syndrome, resulting in amputation of the lower extremity. Greater awareness of both thromboembolic disease in children and the white clot syndrome may lessen the morbidity and mortality associated with these entities.

Use of practice tracks in the medical specialties

OBJECTIVES

To evaluate the use of practice tracks by each of the 24 medical specialty boards and to compare this with the experience in emergency medicine (EM).

METHODS

Scripted telephone surveys were conducted with representatives of each of the specialty boards.

RESULTS

Of 24 specialties currently recognized by the American Board of Medical Specialties (ABMS), 14 (58%) reported a history of a practice track. Eight boards reported never having a practice track and 2 were unsure. All practice tracks have been limited in duration, most commonly closing after a specified period. The mean duration of the practice tracks was 9.8 years, the median was 7.5 years, and the range was 3-27 years. The practice track in EM was open for 9 years.

CONCLUSIONS

Practice tracks were common in the early years of most specialties and most were limited by duration. The history of the practice track in EM is not dissimilar to those of other specialties.

Air medical tracheal intubation: establishing a threshold for this QA indicator

Endotracheal intubation is a critical skill necessary in a number of situations encountered by air medical personnel. The purpose of this study was to establish a threshold for the quality assurance indicator of successful tracheal intubation in a physician-staffed air medical system. The records of all patients transported by a physician-staffed air medical system over a 36-month period were reviewed. One hundred and forty-three patients had endotracheal intubation attempted. Blind nasotracheal intubation attempts were successful in 71% of those in whom it was attempted, while the overall intubation success rate was 92%. Based on this study and the existing literature, a threshold of 90% is recommended for the quality assurance indicator of successful tracheal intubation in physician-staffed air medical systems.

Characterization of acetylcholinesterase activity from Drosophila melanogaster

The acetylcholinesterase activity of the fruit fly, Drosophila melanogaster, was characterized biochemically. The activity is associated with a glycoprotein which is divided between a detergent-extractable membrane-bound fraction and a soluble fraction. The acetylcholinesterase activity is concentrated in the head of the insect. Through pharmacological methods, greater than 95% of the cholinesterase is judged to be true acetylcholinesterase, and not pseudocholinesterase. As expected for an acetylcholinesterase, the enzyme has a high affinity for acetylthiocholine and is inhibited by excess concentrations of acetylthiocholine. The soluble enzyme is found predominantly as a 7.8 S form; a smaller amount of an approximately 6 S form is also present, and a greater than or equal to 14 S form may exist. The detergent-solubilized acetylcholinesterase has a sedimentation coefficient of 7.5 S in the presence of detergent. The thermal inactivation rates for the soluble and the membrane bound enzymes are markedly different.