Assessing the one-month mortality impact of civilian-setting prehospital transfusion: A systematic review and meta-analysis

BACKGROUND

Based on convincing evidence for outcomes improvement in the military setting, the past decade has seen evaluation of prehospital transfusion (PHT) in the civilian emergency medical services (EMS) setting. Evidence synthesis has been challenging, due to study design variation with respect to both exposure (type of blood product administered) and outcome (endpoint definitions and timing). The goal of the current meta-analysis was to execute an overarching assessment of all civilian-arena randomized controlled trial (RCT) evidence focusing on administration of blood products compared to control of no blood products.

METHOD

The review structure followed the Cochrane group's Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA). Using the Transfusion Evidence Library (transfusionevidencelibrary.com), the multidatabase (e.g. PubMed, EMBASE) Harvard On-Line Library Information System (HOLLIS), and GoogleScholar, we accessed many databases and gray literature sources. RCTs of PHT in the civilian setting with a comparison group receiving no blood products with 1-month mortality outcomes were identified.

RESULTS

In assessing a single patient-centered endpoint-1-month mortality-we calculated an overall risk ratio (RR) estimate. Analysis of three RCTs yielded a model with acceptable heterogeneity (I2 = 48%, Q-test p = 0.13). Pooled estimate revealed civilian PHT results in a statistically nonsignificant (p = 0.38) relative mortality reduction of 13% (RR 0.87, 95% CI 0.63-1.19).

CONCLUSIONS

Current evidence does not demonstrate 1-month mortality benefit of civilian-setting PHT. This should give pause to EMS systems considering adoption of civilian-setting PHT programs. Further studies should not only focus on which formulations of blood products might improve outcomes but also focus on which patients are most likely to benefit from any form of civilian-setting PHT.

Characterizing malpractice cases involving emergency department advanced practice providers, physicians in training, and attending physicians

OBJECTIVE

The objective was to evaluate available characteristics and financial costs of malpractice cases among advanced practice providers (APPs; nurse practitioners [NPs] and physician assistants [PAs]), trainees (medical students, residents, fellows), and attending physicians.

METHODS

This study was a retrospective analysis of claims occurring in the emergency department (ED) from January 1, 2010, to December 31, 2019, contained in the Candello database. Cases were classified according to the provider type(s) involved: NP, PA, trainee, or cases that did not identify an extender as being substantially involved in the adverse event that resulted in the case ("no extender").

RESULTS

There were 5854 cases identified with a total gross indemnity paid of $1,007,879,346. Of these cases, 193 (3.3%) involved an NP, 513 (8.8%) involved a PA, 535 (9.1%) involved a trainee, and 4568 (78.0%) were no extender. Cases where a trainee was involved account for the highest average gross indemnity paid whereas no-extender cases are the lowest. NP and PA cases differed by contributing factors compared to no-extender cases: clinical judgment (NP 89.1% vs. no extender 76.8%, p < 0.0001; PA 84.6% vs. no extender, p < 0.0001), documentation (NP 23.3% vs. no extender 17.8%, p = 0.0489; PA 25.9% vs. no extender, p < 0.0001), and supervision (NP 22.3% vs. no extender 1.8%, p < 0.0001; PA 25.7% vs. no extender p < 0.0001). Cases involving NPs and PAs had a lower percentage of high-severity cases such as loss of limb or death (NP 45.6% vs. no extender 50.2%, p = 0.0004; PA 48.3% vs. no extender, p < 0.0001).

CONCLUSIONS

APPs and trainees comprise approximately 21% of malpractice cases and 33% of total gross indemnity paid in this large national ED data set. Understanding differences in characteristics of malpractice claims that occur in emergency care settings can be used to help to mitigate provider risk.

Pathway-Based Reduction of Repeat Head Computed Tomography for Patients With Complicated Mild Traumatic Brain Injury: Implementation and Outcomes

BACKGROUND

Routine follow-up head imaging in complicated mild traumatic brain injury (cmTBI) patients has not been shown to alter treatment, improve outcomes, or identify patients in need of neurosurgical intervention. We developed a follow-up head computed tomography (CT) triage algorithm for cmTBI patients to decrease the number of routine follow-up head CT scans obtained in this population.

OBJECTIVE

To report our experience with protocol implications and patient outcome.

METHODS

Data on all cmTBI patients presenting from July 1, 2018 to June 31, 2019, to our level 1, tertiary, academic medical center were collected prospectively and analyzed retrospectively. Descriptive analysis was performed.

RESULTS

Of the 178 patients enrolled, 52 (29%) received a follow-up head CT. A total of 27 patients (15%) were scanned because of initial presentation and triaged to the group to receive a routine follow-up head CT. A total of 151 patients (85%) were triaged to the group without routine follow-up head CT scan. Protocol adherence was 89% with 17 violations.

CONCLUSION

Utilizing this protocol, we were able to safely decrease the use of routine follow-up head CT scans in cmTBI patients by 71% without any missed injuries or delayed surgery. Adoption of the protocol was high among all services managing TBI patients.

Getting to the heart of the issue: senior emergency resident electrocardiogram interpretation and its impact on quality assurance events

Objective

Electrocardiogram (ECG) interpretation skills are of critical importance for diagnostic accuracy and patient safety. In our emergency department (ED), senior third-year emergency medicine residents (EM3s) are the initial interpreters of all ED ECGs. While this is an integral part of emergency medicine education, the accuracy of ECG interpretation is unknown. We aimed to review the adverse quality assurance (QA) events associated with ECG interpretation by EM3s.

Methods

We conducted a retrospective study of all ED ECGs performed between October 2015 and October 2018, which were read primarily by EM3s, at an urban tertiary care medical center treating 56,000 patients per year. All cases referred to the ED QA committee during this time were reviewed. Cases involving a perceived error were referred to a 20-member committee of ED leadership staff, attendings, residents, and nurses for further consensus review. Ninety-five percent confidence intervals (CIs) were calculated.

Results

EM3s read 92,928 ECGs during the study period. Of the 3,983 total ED QA cases reviewed, errors were identified in 268 (6.7%; 95% CI, 6.0%–7.6%). Four of the 268 errors involved ECG misinterpretation or failure to act on an ECG abnormality by a resident (1.5%; 95% CI, 0.0%–2.9%).

Conclusion

A small percentage of the cases referred to the QA committee were a result of EM3 misinterpretation of ECGs. The majority of emergency medicine residencies do not include the senior resident as a primary interpreter of ECGs. These findings support the use of EM3s as initial ED ECG interpreters to increase their clinical exposure.

0950 Effects of Sodium Oxybate (SXB) on Body Mass Index (BMI) in Pediatric Patients With Narcolepsy

Introduction

Obesity is a common comorbidity of pediatric narcolepsy. SXB is a standard of care for cataplexy and excessive daytime sleepiness in narcolepsy. BMI decreases have been observed with SXB treatment. We examined BMI changes by BMI percentile category at study entry in pediatric participants.

Methods

Participants were aged 7-17 years with narcolepsy with cataplexy. SXB-naive participants were titrated to an optimal SXB dose, then entered a 2-week stable-dose period; participants taking SXB at study entry entered a 3-week stable-dose period. After a 2-week, placebo-controlled, double-blind, randomized-withdrawal period, all participants entered an open-label safety period (total study duration: ≤1 year). Weight categories were defined using BMI percentiles at study entry based on growth charts from the Centers for Disease Control. BMI percentile was categorized as: underweight (&lt;5%ile), normal (≥5%ile to &lt;85%ile), overweight (≥85%ile to&lt;95%ile), obese (≥95%ile).

Results

Among SXB-naive participants, median (Q1, Q3) BMI percentile decreased with SXB treatment in participants who were categorized as normal-weight and overweight/obese at baseline (normal-weight, n=16: 76.5 [57.8, 82.4] at baseline, 35.0 [20.5, 62.6] at week 52; overweight/obese, n=35: 97.6 [93.6, 99.1] at baseline, 86.7 [72.5, 97.9] at week 52). Of participants who were normal-weight at baseline, 15/16 remained normal-weight at week 52. Of participants who were overweight at baseline, 9/10 were normal-weight at week 52. Of participants who were obese at baseline, 7/25 were normal-weight, 3/25 were overweight, and 15/25 remained obese at week 52. Among participants taking SXB at study entry, BMI percentile decreased, but to a lesser degree. Decreased weight or weight loss was reported as an adverse event in 13 participants (11 SXB-naive; 1 participant withdrew). Four participants became underweight during the study but returned to normal-weight by study end.

Conclusion

Decreases in BMI percentile and category were observed with SXB treatment in pediatric participants with narcolepsy.

Support

Jazz Pharmaceuticals

Standardized Video Interview Scores Correlate Poorly with Faculty and Patient Ratings

The Standardized Video Interview (SVI) was developed by the Association of American Medical Colleges to assess professionalism, communication, and interpersonal skills of residency applicants. How SVI scores compare with other measures of these competencies is unknown. The goal of this study was to determine whether there is a correlation between the SVI score and both faculty and patient ratings of these competencies in emergency medicine (EM) applicants. This was a retrospective analysis of a prospectively collected dataset of medical students. Students enrolled in the fourth-year EM clerkship at our institution and who applied to the EM residency Match were included. We collected faculty ratings of the students’ professionalism and patient care/communication abilities as well as patient ratings using the Communication Assessment Tool (CAT) from the clerkship evaluation forms. Following completion of the clerkship, students applying to EM were asked to voluntarily provide their SVI score to the study authors for research purposes. We compared SVI scores with the students’ faculty and patient scores using Spearman’s rank correlation. Of the 43 students from the EM clerkship who applied in EM during the 2017–2018 and 2018–2019 application cycles, 36 provided their SVI scores. All 36 had faculty evaluations and 32 had CAT scores available. We found that SVI scores did not correlate with faculty ratings of professionalism (rho = 0.09, p = 0.13), faculty assessment of patient care/communication (rho = 0.12, p = 0.04), or CAT scores (rho = 0.11, p = 0.06). Further studies are needed to validate the SVI and determine whether it is indeed a predictor of these competencies in residency.

Diagnostic error, quality assurance, and medical malpractice/risk management education in emergency medicine residency training programs

Background

Diagnostic errors in emergency medicine (EM) can lead to patient harm as well as potential malpractice claims and quality assurance (QA) reviews. It is therefore essential that these topics are part of the core education of trainees. The methods training programs use to educate residents on these topics are unknown. The goal of this study was to identify the current methods used to teach EM residents about diagnostic errors, QA, and malpractice/risk management and determine the amount of educational teaching time EM programs dedicate to these topics.

Methods

An 11-item questionnaire pertaining to resident education on diagnostic errors, QA, and malpractice was sent through the Council of Emergency Medicine Residency Directors (CORD) listserv. Differences in the proportions of responses by duration of training program were analyzed using chi-squared or Fisher’s exact tests.

Results

Fifty-four percent (91/168) of the EM programs responded. There was no difference in prevalence of formal education on these topics among 3- and 4-year programs. The majority of programs (59.5%) offer fewer than 4 h per year of additional QA education beyond morbidity and mortality rounds; a minority of the programs (18.8%) offer more than 4 h per year of medical malpractice/risk management education.

Conclusions

This needs assessment demonstrated that there is a lack of dedicated educational time devoted to these topics. A more formalized and standard curricular approach with increased time allotment may enhance EM resident education about diagnostic errors, QA, and malpractice/risk management.

The Potential Role of Ultrasound in the Work-up of Appendicitis in the Emergency Department

BACKGROUND

Acute appendicitis is common in the adult emergency department (ED). Computed tomography (CT) scan is frequently used to diagnose this condition, but ultrasound (US)-commonly used in pediatric diagnosis-may also have a role.

OBJECTIVES

Review the clinical utility and define the frequency and diagnostic accuracy of US to diagnose appendicitis in an adult population in the ED setting.

METHODS

Retrospective cohort study of patients who underwent appendiceal US in an academic, tertiary ED from July 2013-October 2015.

RESULTS

There were 174 patients included, of which 39 (22%) had pathology-confirmed appendicitis. There were 25 patients who had an US scan that was positive for appendicitis, 146 (84%) were indeterminate, and 3 (1.7%) were negative. Among patients with a positive US, 25/25 (100%, 95% confidence interval [CI] 84-100%) had appendicitis, 32/146 (22%, 95% CI 16-29%) with an indeterminate US had appendicitis, and 0/3 (0%, 95% CI 0-6.2%) with a negative US had appendicitis. In the 28 definitive cases, US had a sensitivity of 64%, specificity of 2%, positive predictive value of 100%, and negative predictive value of 100%. The likelihood ratio positive and negative were 173 and 0, respectively.

CONCLUSION

Our initial data suggest that an US that shows appendicitis seems to be reliable; however, a high prevalence of indeterminate studies limits the diagnostic utility as a universal approach in adult patients in the ED setting. Larger studies are needed to identify which patient populations would benefit from US as the initial imaging modality, what factors contribute to the large numbers of indeterminate results, and if any interventions may reduce the number of indeterminate results.

Comparison of Emergency Medicine Malpractice Cases Involving Residents to Nonresident Cases

BACKGROUND

Data are lacking on how emergency medicine (EM) malpractice cases with resident involvement differs from cases that do not name a resident.

OBJECTIVES

The objective was to compare malpractice case characteristics in cases where a resident is involved (resident case) to cases that do not involve a resident (nonresident case) and to determine factors that contribute to malpractice cases utilizing EM as a model for malpractice claims across other medical specialties.

METHODS

We used data from the Controlled Risk Insurance Company (CRICO) Strategies' division Comparative Benchmarking System (CBS) to analyze open and closed EM cases asserted from 2009 to 2013. The CBS database is a national repository that contains professional liability data on > 400 hospitals and > 165,000 physicians, representing over 30% of all malpractice cases in the United States (>350,000 claims). We compared cases naming residents (either alone or in combination with an attending) to those that did not involve a resident (nonresident cohort). We reported the case statistics, allegation categories, severity scores, procedural data, final diagnoses, and contributing factors. Fisher's exact test or t-test was used for comparisons (alpha set at 0.05).

RESULTS

A total of 845 EM cases were identified of which 732 (87%) did not name a resident (nonresident cases), while 113 (13%) included a resident (resident cases). There were higher total incurred losses for nonresident cases. The most frequent allegation categories in both cohorts were "failure or delay in diagnosis/misdiagnosis" and "medical treatment" (nonsurgical procedures or treatment regimens, i.e., central line placement). Allegation categories of safety and security, patient monitoring, hospital policy and procedure, and breach of confidentiality were found in the nonresident cases. Resident cases incurred lower payments on average ($51,163 vs. $156,212 per case). Sixty-six percent (75) of resident versus 57% (415) of nonresident cases were high-severity claims (permanent, grave disability or death; p = 0.05). Procedures involved were identified in 32% (36) of resident and 26% (188) of nonresident cases (p = 0.17). The final diagnoses in resident cases were more often cardiac related (19% [21] vs. 10% [71], p < 0.005) whereas nonresident cases had more orthopedic-related final diagnoses (10% [72] vs. 3% [3], p < 0.01). The most common contributing factors in resident and nonresident cases were clinical judgment (71% vs. 76% [p = 0.24]), communication (27% vs. 30% [p = 0.46]), and documentation (20% vs. 21% [p = 0.95]). Technical skills contributed to 20% (22) of resident cases versus 13% (96) of nonresident cases (p = 0.07) but those procedures involving vascular access (2.7% [3] vs 0.1% [1]) and spinal procedures (3.5% [4] vs. 1.1% [8]) were more prevalent in resident cases (p < 0.05 for each).

CONCLUSIONS

There are higher total incurred losses in nonresident cases. There are higher severity scores in resident cases. The overall case profiles, including allegation categories, final diagnoses, and contributing factors between resident and nonresident cases are similar. Cases involving residents are more likely to involve certain technical skills, specifically vascular access and spinal procedures, which may have important implications regarding supervision. Clinical judgment, communication, and documentation are the most prevalent contributing factors in all cases and should be targets for risk reduction strategies.

Experience Within the Emergency Department and Improved Productivity for First-Year Residents in Emergency Medicine and Other Specialties

Introduction

Resident productivity is an important educational and operational measure in emergency medicine (EM). The ability to continue effectively seeing new patients throughout a shift is fundamental to an emergency physician’s development, and residents are integral to the workforce of many academic emergency departments (ED). Our previous work has demonstrated that residents make gains in productivity over the course of intern year; however, it is unclear whether this is from experience as a physician in general on all rotations, or specific to experience in the ED.

Methods

This was a retrospective cohort study, conducted in an urban academic hospital ED, with a three-year EM training program in which first-year residents see new patients ad libitum. We evaluated resident shifts for the total number of new patients seen. We constructed a generalized estimating equation to predict productivity, defined as the number of new patients seen per shift, as a function of the week of the academic year, the number of weeks spent in the ED, and their interaction. Off-service residents’ productivity in the ED was analyzed in a secondary analysis.

Results

We evaluated 7,779 EM intern shifts from 7/1/2010 to 7/1/2016. Interns started at 7.16 (95% confidence interval [CI] [6.87 – 7.45]) patients per nine-hour shift, with an increase of 0.20 (95% CI [0.17 – 0.24]) patients per shift for each week in the ED, over 22 weeks, leading to 11.5 (95% CI [10.6 – 12.7]) patients per shift at the end of their training in the ED. The effects of the week of the academic year and its interaction with weeks in the ED were not significant. We evaluated 2,328 off-service intern shifts, in which off-service residents saw 5.43 (95% CI [5.02 – 5.84]) patients per nine-hour shift initially, with 0.46 additional patients per week in the ED (95% CI [0.25 – 0.68]). The weeks of the academic year were not significant.

Conclusion

Intern productivity in EM correlates with time spent training in the ED, and not with experience on other rotations. Accordingly, an EM intern’s productivity should be evaluated relative to their aggregate time in the ED, rather than the time in the academic year.

Cultural Competency Training in Emergency Medicine

BACKGROUND

The Emergency Department is widely regarded as the epicenter of medical care for diverse and largely disparate types of patients. Physicians must be aware of the cultural diversity of their patient population to appropriately address their medical needs. A better understanding of residency preparedness in cultural competency can lead to better training opportunities and patient care.

OBJECTIVE

The objective of this study was to assess residency and faculty exposure to formal cultural competency programs and assess future needs for diversity education.

METHODS

A short survey was sent to all 168 Accreditation Council for Graduate Medical Education program directors through the Council of Emergency Medicine Residency Directors listserv. The survey included drop-down options in addition to open-ended input. Descriptive and bivariate analyses were used to analyze data.

RESULTS

The response rate was 43.5% (73/168). Of the 68.5% (50/73) of residency programs that include cultural competency education, 90% (45/50) utilized structured didactics. Of these programs, 86.0% (43/50) included race and ethnicity education, whereas only 40.0% (20/50) included education on patients with limited English proficiency. Resident comfort with cultural competency was unmeasured by most programs (83.6%: 61/73). Of all respondents, 93.2% (68/73) were interested in a universal open-source cultural competency curriculum.

CONCLUSIONS

The majority of the programs in our sample have formal resident didactics on cultural competency. Some faculty members also receive cultural competency training. There are gaps, however, in types of cultural competency training, and many programs have expressed interest in a universal open-source tool to improve cultural competency for Emergency Medicine residents.

The Integration of Electronic Medical Student Evaluations Into an Emergency Department Tracking System is Associated With Increased Quality and Quantity of Evaluations

BACKGROUND

Medical student evaluations are essential for determining clerkship grades. Electronic evaluations have various advantages compared to paper evaluations, such as increased ease of collection, asynchronous reporting, and decreased likelihood of becoming lost.

OBJECTIVES

To determine whether electronic medical student evaluations (EMSEs) provide more evaluations and content when compared to paper shift card evaluations.

METHODS

This before and after cohort study was conducted over a 2.5-year period at an academic hospital affiliated with a medical school and emergency medicine residency program. EMSEs replaced the paper shift evaluations that had previously been used halfway through the study period. A random sample of the free text comments on both paper and EMSEs were blindly judged by medical student clerkship directors for their helpfulness and usefulness. Logistic regression was used to test for any relationship between quality and quantity of words.

RESULTS

A total of 135 paper evaluations for 30 students and then 570 EMSEs for 62 students were collected. An average of 4.8 (standard deviation [SD] 3.2) evaluations were completed per student using the paper version compared to 9.0 (SD 3.8) evaluations completed per student electronically (p < 0.001). There was an average of 8.8 (SD 8.5) words of free text evaluation on paper evaluations when compared to 22.5 (SD 28.4) words for EMSEs (p < 0.001). A statistically significant (p < 0.02) association between quality of an evaluation and the word count existed.

CONCLUSIONS

EMSEs that were integrated into the emergency department tracking system significantly increased the number of evaluations completed compared to paper evaluations. In addition, the EMSEs captured more "helpful/useful" information about the individual students as evidenced by the longer free text entries per evaluation.

Factors that influence medical student selection of an emergency medicine residency program: implications for training programs

OBJECTIVES

An understanding of student decision-making when selecting an emergency medicine (EM) training program is essential for program directors as they enter interview season. To build upon preexisting knowledge, a survey was created to identify and prioritize the factors influencing candidate decision-making of U.S. medical graduates.

METHODS

This was a cross-sectional, multi-institutional study that anonymously surveyed U.S. allopathic applicants to EM training programs. It took place in the 3-week period between the 2011 National Residency Matching Program (NRMP) rank list submission deadline and the announcement of match results.

RESULTS

Of 1,525 invitations to participate, 870 candidates (57%) completed the survey. Overall, 96% of respondents stated that both geographic location and individual program characteristics were important to decision-making, with approximately equal numbers favoring location when compared to those who favored program characteristics. The most important factors in this regard were preference for a particular geographic location (74.9%, 95% confidence interval [CI] = 72% to 78%) and to be close to spouse, significant other, or family (59.7%, 95% CI = 56% to 63%). Factors pertaining to geographic location tend to be out of the control of the program leadership. The most important program factors include the interview experience (48.9%, 95% CI = 46% to 52%), personal experience with the residents (48.5%, 95% CI = 45% to 52%), and academic reputation (44.9%, 95% CI = 42% to 48%). Unlike location, individual program factors are often either directly or somewhat under the control of the program leadership. Several other factors were ranked as the most important factor a disproportionate number of times, including a rotation in that emergency department (ED), orientation (academic vs. community), and duration of training (3-year vs. 4-year programs). For a subset of applicants, these factors had particular importance in overall decision-making.

CONCLUSIONS

The vast majority of applicants to EM residency programs employed a balance of geographic location factors with individual program factors in selecting a residency program. Specific program characteristics represent the greatest opportunity to maximize the success of the immediate interview experience/season, while others provide potential for strategic planning over time. A working knowledge of these results empowers program directors to make informed decisions while providing an appreciation for the limitations in attracting applicants.

Pathophysiology of the vascular wall and its relevance for cerebrovascular disorders in aged rodents

Chronic hypertension and cerebral amyloid angiopathy (CAA) are the main pathologies which can induce the rupture of cerebral vessels and intracerebral hemorrhages, as a result of degenerative changes in the vascular wall. A lot of progress has been made in this direction since the successful creation of the first mouse model for the study of Alzheimer's disease (AD), as the spectrum of AD pathology includes a plethora of changes found in pure cerebrovascular diseases. We describe here some of these mouse models having important vascular changes that parallel human AD pathology, and more importantly, we show how these models have helped us understand more about the mechanisms that lead to CAA formation. An important cellular event associated with reduced structural and functional recovery after stroke in aged animals is the early formation of a scar in the infarcted region that impairs subsequent neural recovery and repair. We review recent evidence showing that the rapid formation of the glial scar following stroke in aged rats is associated with premature cellular proliferation that originates primarily from the walls of capillaries in the corpus callosum adjacent to the infarcted region. After stroke several vascular mechanisms are turned-on immediately to protect the brain from further damage and help subsequent neuroregeneration and functional recovery. Although does occur after stroke, vasculogenesis is overshadowed in its protective/restorative role by the angiogenesis and arteriogenesis. Understanding the basic mechanisms underlying functional recovery after cerebral stroke in aging subjects is likely to yield new insights into the treatment of brain injury in the clinic.

Cervical spine injuries in children, part II: management and special considerations

BACKGROUND

The diagnosis and management of cervical spine injury is more complex in children than in adults.

OBJECTIVES

Part I of this series stressed the importance of tailoring the evaluation of cervical spine injuries based on age, mechanism of injury, and physical examination findings. Part II will discuss the role of magnetic resonance imaging (MRI) as well as the management of pediatric cervical spine injuries in the emergency department.

DISCUSSION

Children have several common variations in their anatomy, such as pseudosubluxation of C2-C3, widening of the atlantodens interval, and ossification centers, that can appear concerning on imaging but are normal. Physicians should be alert for signs or symptoms of atlantorotary subluxation and spinal cord injury without radiologic abnormality when treating children with spinal cord injury, as these conditions have significant morbidity. MRI can identify injuries to the spinal cord that are not apparent with other modalities, and should be used when a child presents with a neurologic deficit but normal X-ray study or CT scan.

CONCLUSION

With knowledge of these variations in pediatric anatomy, emergency physicians can appropriately identify injuries to the cervical spine and determine when further imaging is needed.

Becoming a specialist in emergency medicine

One of the strengths of American medicine is the specialty training program. It is the purpose of this report to highlight some of the most important considerations in specialty training programs, which include the following: 1) resident selection process, 2) patient history taking, 3) residency training, 4) morbidity and mortality conference, and 5) mentoring residents. Residents are chosen for intelligence, past successful performance, and for personal compatibility. It is hoped that one has been able to gauge successfully their motivation, as well as the willingness to work hard. History taking, which is so important a part of data acquisition, is much more than asking the series of questions we were all taught in medical school. The experienced physician must have judgment and experience as to what are the right questions to ask, but must also have experience in the interpretation of patients' answers. Residency is, then, in part, learning how to ask the right questions, as well as how to interpret the right answers. We think that one of the most important ways to become an experienced Emergency Physician is to have a large number of bad experiences that are recognized and corrected, in an environment that encourages honesty as well as adequate supervision. Morbidity and mortality conferences must be an integral part of training Emergency Medicine residents.

Ultrasound detection of abdominal aortic aneurysm

US is becoming a widely used diagnostic and therapeutic tool in emergency medicine training and practice. Its use in detecting an AAA is efficient and practical and can occur concurrently with resuscitation. US of the abdominal aorta has been shown to be highly accurate for the detection of AAA and to decrease the time to operative repair of ruptured AAA. The emergency physician should consider using US to search for an AAA in any patient presenting with abdominal or back pain or with shock of unknown etiology.

Outcome analysis of preoperative embolization in cranial base surgery

OBJECTIVE

Management of cranial base tumors requires an interdisciplinary approach. Supraselective angiography and embolization is an important adjunct to cranial base surgery. Though successful embolization facilitates resection, the morbidity of this procedure remains poorly defined. Therefore, we set out to define the morbidity associated with embolization of skull base meningiomas, thus allowing for informed decision making when considering this adjunct to tumor resection.

METHODS

A retrospective analysis was performed on our experience with embolization of 167 cranial base meningiomas. Cranial base meningiomas were defined as tumors originating from the olfactory groove, tuberculum sella, medial sphenoid wing, petro-clival region or foramen magnum.

RESULTS

280 feeding vessels were embolized with an average of 1.7 vessels per lesion. In 91% of patients embolized, good to excellent embolization was achieved without permanent neurological sequelae. In 20 patients no embolization was attempted due to the risk of new neurologic deficits or lack of an appropriate vessel for embolization. Twenty-one patients (12.6%) had transient worsening of their neurologic exam or a medical complication requiring hospitalization. Fifteen patients (9%) experienced permanent neurologic deficits or medical morbidity as a result of embolization. Four of the patients who experienced major complications had a decline in previously compromised cranial nerve function.

CONCLUSIONS

Embolization of cranial base tumors is an important part of the therapeutic armamentarium for the treatment of cranial base lesions. Recognition of the morbidity of this procedure will allow for the most appropriate use of this powerful adjunct to cranial base surgery.

The diagnosis of lower extremity deep venous thrombosis

The diagnosis of lower extremity deep venous thrombosis (DVT) is critical to emergency physicians because of the risk of pulmonary embolism. This article reviews the diagnostic modalities available for patients with suspected lower extremity DVT. The use of compression ultrasonography and the recent advances in the D-dimer assays are emphasized. A clinical algorithm that utilizes a non invasive approach to this potentially life threatening disease is presented.

Ultrasonography by emergency physicians in patients with suspected cholecystitis

This article investigates the use of bedside abdominal ultrasonography (BAU) performed by emergency physicians (EPs) to screen patients for cholelithiasis and cholecystitis. In this prospective study EPs performed BAU on 116 patients. Agreement between BAU and formal abdominal ultrasound (FUS) performed in the radiology department for detecting cholelithiasis and cholecystitis was determined using Kappa statistics. Test characteristics of BAU for detecting cholelithiasis and acute cholecystitis were calculated. Agreement between BAU and FUS was 0.71 for cholelithiasis and 0.46 for acute cholecystitis. Test characteristics of BAU for cholelithiasis were sensitivity 92%, specificity 78%, positive predictive value (PPV) 86%, negative predictive value (NPV) 88%. Test characteristics of BAU for acute cholecystitis compared with clinical follow-up were sensitivity 91%, specificity 66%, PPV 70%, NPV 90%. BAU may be used to exclude cholelithiasis and is sensitive for cholecystitis. However, when EPs with limited experience identify cholecystitis a confirmatory test is warranted before cholecystectomy.

Treatment of sleep-disordered breathing in children with myelomeningocele

The prevalence of moderate to severe sleep-disordered breathing (SDB) in patients with myelomeningocele may be as high as 20%, but little information is available regarding treatment of these patients. To assess the efficacy and complications of treatments for these children, we collected data on 73 patients from seven pediatric sleep laboratories. Obstructive sleep apnea (OSA, n = 30) and central apnea (n = 25) occurred more frequently than central hypoventilation (n = 12). We also describe a sleep-exacerbated restrictive lung disease type of SDB in 6 patients who had hypoxemia during sleep without apnea or central hypoventilation. For each type of SDB, effective treatments were identified in a stepwise process, moving towards more complex and invasive therapies. For OSA, adenotonsillectomy was often ineffective (10/14), whereas nasal continuous positive airway pressure (CPAP) was usually successful (18/21). For central apnea, methylxanthines and/or supplemental oxygen proved sufficient in 2 of 9 and 3 of 6, respectively, but noninvasive positive pressure ventilation was required in 7 children. For central hypoventilation, supplemental oxygen (alone or with methylxanthines), noninvasive positive pressure ventilation, and tracheostomy with positive pressure ventilation were effective in 3, 2, and 2 patients, respectively. Sleep-exacerbated restrictive lung disease always required supplemental oxygen treatment, but in 2 cases also required noninvasive positive pressure ventilation; nutritional and orthopedic procedures also were helpful. Posterior fossa decompression was used for the first three types of SDB, but data were insufficient to delineate specific recommendations for or against its use. In summary, evaluation by an experienced, multidisciplinary team can establish an effective treatment regime for a child with myelomeningocele and SDB.

Primary angiitis of the central nervous system as a first presentation in Hodgkin's disease: a case report and review of the literature

OBJECTIVE AND IMPORTANCE

Granulomatous angiitis of the central nervous system is a rare cause of neurological deterioration. It is often diagnosed posthumously, and a high index of suspicion is necessary to make the correct diagnosis on a timely basis.

CLINICAL PRESENTATION

A 27-year-old woman presented to the emergency room with complaints of worsening headache, nausea, and vomiting for 10 days, which were preceded by swelling of her tongue. At the examination, she had mild ocular tenderness, but no cranial nerve abnormalities. Radiographic examination revealed a right temporal lobe area with edema, and mild contrast enhancement was noted on computed tomography and magnetic resonance imaging. A similar but smaller region was present in the left frontal lobe.

INTERVENTION

Stereotactic biopsy of the left temporal lobe revealed granulomatous angiitis. Further workup revealed Hodgkin's disease in the mediastinum. Dexamethasone as well as chemotherapy for Hodgkin's disease was initiated. The patient's symptoms resolved, and she returned to work with her disease in remission.

CONCLUSION

Previous reports of central nervous system angiitis have shown an association with Sjogren's syndrome, herpes zoster infection, human immunodeficiency virus, and Hodgkin's disease. A review of the literature revealed a total of 12 patients with central nervous system angiitis and Hodgkin's disease. As a group, these patients had very poor outcomes. However, of six patients who presented with central nervous system angiitis and concurrent Hodgkin's disease and who underwent aggressive treatment for both conditions, three had a full recovery, two had a partial recovery, and one died.

Use of intra-aortic balloon pump counterpulsation for refractory symptomatic vasospasm

Delayed neurologic deficits secondary to vasospasm remain a vexing problem. Current treatments include: hypertensive hypervolemic hemodilution (Triple-H) therapy, angioplasty, and intra-arterial papaverine administration. Significant morbidity and mortality still result from vasospasm despite these therapies. We present two patients with symptomatic vasospasm who received intra-aortic balloon pump counterpulsation (IABP) to improve cerebral blood flow when they were unable to tolerate Triple-H therapy. One patient (L.T.) developed vasospasm after resection of a meningioma that encased the carotid and middle cerebral artery. The other patient (D.F.) suffered a subarachnoid hemorrhage (Fisher Grade III, Hunt/Hess Grade III) from a basilar tip aneurysm. Postoperatively, both patients developed vasospasm. Treatment with Triple-H therapy, angioplasty, and papaverine yielded modest results. When they experienced cardiac ischemia, Triple-H therapy was stopped, but their neurologic condition deteriorated markedly. Because of this, IABP was started. Both patients had an immediate improvement in cardiac function. IABP was able to reverse some of the neurologic deficits, and was weaned off after several days of support. Both patients had a substantial improvement in function, and are now capable of caring for themselves. We conclude that IABP may play an important role for improving cerebral blood flow in patients with vasospasm. It may be particularly useful in those patients with limited cardiac reserve.

Early predictors of myoglobinuria and acute renal failure following electrical injury

Myoglobinuria-induced acute renal failure (ARF) is a potentially lethal consequence of electrical injury. We describe clinical variables that can predict the risk of myoglobinuria and ARF following electrical injury. This was a retrospective multivariate analysis of risk factors among electrically injured patients over a 26-year period. Urine myoglobin status was documented in 162 patients; 14% had myoglobinuria. No patient developed ARF. Multivariate modeling revealed that high-voltage exposure, prehospital cardiac arrest, full-thickness burns, and compartment syndrome were associated with myoglobinuria. Using a prediction rule defined as positive when a patient had > or = 2 risk factors yielded a sensitivity of 96% and negative predictive value of 99%. Electrical injury patients with myoglobinuria have little risk of developing ARF. A prediction rule can be used to screen out patients at low risk for myoglobinuria and identify high-risk patients who warrant early aggressive treatment and a more definitive myoglobin test.

Proposed grading system to predict the extent of resection and outcomes for cranial base meningiomas

OBJECTIVE

This investigation was performed to construct a grading system for cranial base meningiomas that augments the current system of topographic labeling. This new system classifies cranial base meningiomas based on predicted surgical resection and patient outcomes.

METHODS

Two hundred thirty-two consecutive patients with cranial base meningiomas were surgically treated by the two senior authors between April 1993 and August 1997. Using standard statistical tests, a large number of preoperative, intraoperative, and follow-up findings were analyzed for correlation with the extent of resection. These included the presence of previous radiotherapy, Cranial Nerve III, V, and VI palsies, multiple fossa involvement, and vessel encasement.

RESULTS

Analysis revealed that each variable tested was independently and inversely correlated with total tumor resection (P < 0.002). We were able to construct a grading system based on these variables; when more variables are present, the grade is higher. With the grading system, lower-grade tumors were correlated with increased probabilities of total resection (r2 = 0.9947) and better patient outcomes, as measured by Karnofsky performance scale scores (r = 0.9291). We also found that, as a group, patients who underwent subtotal resection exhibited worse Karnofsky performance scale scores and had longer hospital stays.

CONCLUSION

The current system of classifying cranial base meningiomas provides no information regarding the tumor except location and no information concerning patient prognosis. We present a more useful system to categorize these tumors. Our scheme must be tested at other centers to corroborate our findings. This new grading system should serve to guide surgical treatment, inform patients, and improve communication among surgeons.

Clinical features of obstructive sleep apnea hypoventilation syndrome in otherwise healthy children

Obstructive sleep apnea hypoventilation syndrome (OSAHS) is an important public health problem. However, major gaps exist in our knowledge about the clinical features of this disorder in the pediatric age group. The purpose of this study was to examine clinical features of OSAHS diagnosed by polysomnography in otherwise healthy children. In this cross-sectional study, 326 children without underlying medical conditions (5.8+/-3.0 years, range 1-12 years; 56% male) were recruited from patients referred by primary care and otorhinolaryngology physicians for evaluation of snoring and difficulty breathing. Ethnic group distribution was African-American (38%), Caucasian (30%), and Hispanic (31%). Complaints of daytime tiredness or sleepiness were reported in 29% of the children. All children underwent overnight polysomnography (N = 330 studies). OSAHS was diagnosed in 59% of the children, based on polysomnographic criteria. The remaining children had either primary snoring (25%); no snoring (10%), or upper airway resistance syndrome (6%). Neither male gender nor obesity increased the likelihood for the diagnosis of OSAHS. However, the incidence of obesity in the study population (28%) was more than twice that of the general pediatric population. African-American children had a greater likelihood for OSAHS diagnosis compared to Hispanic or Caucasian children. Daytime complaints of sleepiness or tiredness were not more common in children diagnosed with OSAHS than in the children without OSAHS. As expected, tonsillar hypertrophy increased the likelihood of OSAHS diagnosis. In summary, many of the clinical features of childhood OSAHS are in marked contrast to those in adults.

Evaluation of the patient with blunt chest trauma: an evidence based approach

The patient who has sustained blunt trauma to the chest can present a diagnostic challenge to the emergency physician. There are several diagnostic modalities available for treating life-threatening injuries to these patients. The authors review published studies to support the use of these tests in diagnosing injuries from blunt thoracic trauma. The article focuses chiefly on two current areas of controversy, the diagnosis of blunt aortic and blunt myocardial injury. Finally, the authors make recommendations for the use of various tests based on the available evidence.

Ultrasonography by emergency physicians in patients with suspected ureteral colic

We performed a prospective study of patients with suspected ureteral colic to evaluate the test characteristics of bedside renal ultrasonography (US) performed by emergency physicians (EPs) for detecting hydronephrosis, and to evaluate how US can be used to predict the likelihood of nephrolithiasis. Thirteen EPs performed US, recorded the presence of hydronephrosis, and made an assessment of the likelihood of nephrolithiasis. All patients underwent i.v. pyelography (IVP) or unenhanced helical computed tomography (CT). There were 126 patients in the study: 84 underwent IVP; 42 underwent helical CT. Test characteristics of bedside US for detecting hydronephrosis were: sensitivity 72%, specificity 73%, positive predictive value (PPV) 85%, negative predictive value (NPV) 54%, accuracy 72%. The PPV and NPV for the ability of the EP to predict nephrolithiasis after performing US were 86% and 75%, respectively. We conclude that bedside US performed by EPs may be used to detect hydronephrosis and help predict the presence of nephrolithiasis.

Sleep disorders in infancy, childhood, and adolescence

Sleep disorders cause substantial problems during infancy, toddlerhood, preschool ages, school ages, and adolescence. They represent the most common behavioral problems facing most parents, as well as some of the most unusual and fascinating disorders known to medicine. Sleep disorders can result from pulmonary problems, neurologic problems, family problems, or psychologic or psychiatric problems. The majority of these disorders can be diagnosed by a comprehensive sleep and medical assessment, but special studies such as polysomnography, multiple sleep latency testing, or video electroencephalographic monitoring are necessary for certain diagnoses. Pediatric sleep disorders represent a true interdisciplinary and developmental field, richly connected with many aspects of health care and medical science. Physicians and other pediatric care providers must become increasingly knowledgeable about sleep disorders to offer the best care to their patients.

Renal ultrasonography

Renal US is one of several imaging modalities available to the emergency physician in the evaluation of patients with acute urologic disorders. It offers excellent anatomic detail without exposure to radiation or contrast agents but does not assess renal function. It is particularly useful in the evaluation of renal colic, although its role here may decrease with increasing availability of helical CT. It also has an important role in excluding bilateral renal obstruction as the cause of acute renal failure. Doppler renal US is likely to take on a more prominent role in the evaluation of renal trauma and is the diagnostic study of choice to rule out renal vein thrombosis. Bedside emergency renal US performed and interpreted by emergency physicians with limited training and experience is gaining in use and acceptance. Its role at present is primarily to identify unilateral hydronephrosis in patients with suspected renal colic. This role is likely to expand in the future as emergency US use grows and technology advances. Bedside emergency renal US may eventually be used in the evaluation of patients with acute renal failure, suspected renal vein thrombosis, and renal trauma.

Mechanisms of pediatric electrical injury. New implications for product safety and injury prevention

OBJECTIVES

To determine age-specific mechanisms of electrical injury in children, to examine product safety regulation of the major sources of electrical injury hazard, and to assess the adequacy of current prevention strategies.

DESIGN

Case series of 144 pediatric and adolescent electrical injuries in patients seen in the specialized burn center and tertiary care hospital between 1970 and 1995, examination of Consumer Product Safety Commission product recall reports for electrical injury hazards between 1973 and 1995, and review of the National Electric Code.

RESULTS

Eighty-six cases of electrical injuries resulted from low-voltage (< 1000-V) exposures, all occurring within the home. In children aged 12 years and younger, household appliance electrical cords and extension cords caused more than 64 (63%) of 102 injuries, whereas wall outlets were responsible for only 14 (15%) of injuries. Fifty-eight cases resulted from high-voltage exposures, accounting for 38 (90%) of 42 injuries in children older than 12 years. No federal safety regulations for electrical cords exist, although voluntary standards have been adopted by many manufacturers. Among 383 consumer products identified by the Consumer Product Safety Commission to be electrical injury hazards, 119 were appliance cords, extension cords, or holiday stringed light sets. Several products numbered more than 1.5 million units in US household distribution prior to the investigation by the Consumer Product Safety Commission.

CONCLUSIONS

Household electrical cords are the major electrocution hazard for children younger than 12 years, yet no federal safety mandates exist. Despite voluntary standards, noncompliant manufacturers can introduce vast numbers of unsafe cords onto the US household market every year. Conversion of existing voluntary safety guidelines into federally legislated standards may be the most effective intervention against pediatric electrocutions.

Blind nasotracheal intubation in the presence of facial trauma

Blind nasotracheal intubation (BNTI) is an effective procedure for the intubation of trauma patients. The presence of major facial trauma has been considered a relative contraindication due to the perceived risk of intracranial placement. The purpose of the present study was to assess the risk of intracranial placement in patients with facial fractures who undergo BNTI. The records of 311 patients with facial fractures were reviewed for methods of intubation and complications. Eighty-two patients underwent BNTI. There were no cases of intracranial placement, significant epistaxis requiring nasal packing, esophageal intubation, or osteomyelitis. Three patients (4%) developed sinusitis and eight (10%) developed aspiration pneumonia. We conclude that the presence of facial trauma does not appear to be a contraindication to BNTI.

Rhinovirus infection associated with serious lower respiratory illness in patients with bronchopulmonary dysplasia

OBJECTIVE

To determine the characteristics of rhinovirus infection in patients with bronchopulmonary dysplasia.

SUBJECTS AND METHODS

Between July 1, 1993, and July 1, 1995, 40 patients with bronchopulmonary dysplasia were identified. Viral cultures were obtained in ambulatory patients presenting with an acute respiratory illness requiring hospitalization or in hospitalized patients with a respiratory deterioration. When rhinovirus was isolated epidemiologic data were collected, and the characteristics of the illness, its severity and outcome were noted. Key features of rhinovirus and respiratory syncytial virus (RSV) bronchiolitis were compared.

RESULTS

There were 8 cases of lower respiratory tract illness associated with rhinovirus infection in 6 infants (mean age, 7.1 +/- 4.1 months) and 1 child (age, 40 months), an incidence of 0.15 infection/patient year. The mean gestational age and birth weight of these patients were 27.3 (+/- 2.75) weeks and 853 (+/-341) g, respectively. There were 5 males. Four patients needed intensive care unit admission and 1 required mechanical ventilation. By comparison there were 13 cases of RSV bronchiolitis, an incidence of 0.25 infection/patient year. The 2 groups were similar epidemiologically and an equal proportion of patients with rhinovirus and RSV needed intensive care unit admission. A greater percentage of patients with RSV required mechanical ventilation (50% vs. 14%), but this difference was not statistically significant. Three cases of rhinovirus were nosocomial, and 1 infant had a second infection. Four patients required 5 hospitalizations caused by rhinovirus infection, and the mean duration of hospital stay was 11 days. All children had sustained worsening in their respiratory status after rhinoviral illness requiring additional therapy.

CONCLUSIONS

Rhinovirus is a common and potentially serious lower respiratory pathogen in bronchopulmonary dysplasia patients. Rhinovirus infection has lasting pulmonary sequelae in these children.

The efficacy of intravenous droperidol in the prehospital setting

Droperidol is used for sedating combative patients in the emergency department (ED). We performed a randomized, prospective, double-blind study to evaluate the efficacy of droperidol in the management of combative patients in the prehospital setting. Forty-six patients intravenously received the contents of 2-cc vials of saline or droperidol (5 mg). Paramedics used a 5-point scale to quantify agitation levels prior to and 5 and 10 min after administration of the vials. Twenty-three patients received droperidol and 23 received saline. At 5 min, patients in the droperidol group were significantly less agitated than were patients in the saline group. At 10 min, this difference was highly significant. Eleven patients in the saline group (48%) required more sedation after arrival in the ED versus 3 patients (13%) in the droperidol group. We conclude that droperidol is effective in sedating combative patients in the prehospital setting.

Obstructive sleep apnea syndrome (OSAS) in children: diagnostic challenges

Obstructive sleep apnea syndrome (OSAS) is increasingly recognized in the pediatric population. It is characterized by a combination of partial upper airway obstruction and intermittent obstructive apnea that disrupts normal ventilation and sleep. It is estimated to occur in 1-3% of children with a peak age of 2 to 5 years. Common symptoms include habitual snoring, difficulty breathing during sleep, restlessness, and witnessed apnea. Adenotonsillar hypertrophy is the most common associated condition in otherwise normal children, but cranialfacial abnormalities, neuromuscular diseases, and obesity are also predisposing factors. Severe OSAS can have serious neurobehavioral and cardiorespiratory consequences including excessive daytime sleepiness, growth failure, school failure, behavioral problems, cor pulmonale, or even death. Diagnosis is based on data from the history, physical exam, and laboratory studies that confirm the presence and severity of the upper airway obstruction. Polysomnography has been the diagnostic tool of choice. Treatment depends on the severity of symptoms and the underlying anatomic and physiologic abnormalities. Since childhood OSAS is usually associated with adenotonsillar hypertrophy, the majority of cases are amenable to surgical treatment. However, there is increasing pediatric experience with CPAP therapy when tonsillectomy and adenoidectomy are either unsuccessful or inappropriate.

Use of nasal continuous positive airway pressure as treatment of childhood obstructive sleep apnea

OBJECTIVE

To determine the safety and efficacy of nasal continuous positive airway pressure (CPAP) for obstructive sleep apnea (OSA) during childhood and the effects of growth and maturation on CPAP requirements.

DESIGN

Retrospective study with use of a written questionnaire administered to pediatric practitioners treating sleep disorders.

SETTING

Nine academic pediatric sleep disorders centers.

RESULTS

Data were obtained for 94 patients. Three percent of patients receiving CPAP were less than 1 year, 29% were 1 to 5 years, 36% were 6 to 12 years, and 32% were 13 to 19 years of age; 64% were boys. The longest duration of CPAP use was 4 years. Indications for CPAP included OSA associated with obesity (27%), craniofacial anomalies (25%), idiopathic OSA persisting after adenoidectomy and tonsillectomy (17%), and trisomy 21 (13%). Continuous positive airway pressure was effective in 81 patients (86%), in one patient it was unsuccessful, and in 12 patients compliance was inadequate. The median pressure required was 8 cm H2O (range, 4 to 20 cm H2O); pressure requirements were independent of age or diagnosis. Twenty-two percent of patients eventually required a modification of CPAP levels. Complications of CPAP were minor. Sixty-four percent of centers reported difficulty in obtaining funding for CPAP.

CONCLUSIONS

Continuous positive airway pressure is safe, effective, and well tolerated by children and adolescents with OSA. Experience in infants is limited. As pressure requirements change with patient growth, we recommend that CPAP requirements be regularly reevaluated over time. The marked center-to-center variability in CPAP use suggests that specific indications for this therapy require clarification.

Cloning of neurotrimin defines a new subfamily of differentially expressed neural cell adhesion molecules

Previous studies in the laboratory indicated that glycosylphosphatidylinositol (GPI)-anchored proteins may generate diversity of the cell surface of different neuronal populations (Rosen et al., 1992). In this study, we have extended these findings and surveyed the expression of GPI-anchored proteins in the developing rat CNS. In addition to several well characterized GPI-anchored cell adhesion molecules (CAMs), we detected an unidentified broad band of 65 kDa that is the earliest and most abundantly expressed GPI-anchored species in the rat CNS. Purification of this protein band revealed that it is comprised of several related proteins that define a novel subfamily of immunoglobulin-like (Ig) CAMs. One of these proteins is the opiate binding-cell adhesion molecule (OBCAM). We have isolated a cDNA encoding a second member of this family, that we have termed neurotrimin, and present evidence for the existence of additional family members. Like OBCAM, with which it shares extensive sequence identity, neurotrimin contains three immunoglobulin-like domains. Both proteins are encoded by distinct genes that may be clustered on the proximal end of mouse chromosome 9. Characterization of the expression of neurotrimin and OBCAM in the developing CNS by in situ hybridization reveals that these proteins are differentially expressed during development. Neurotrimin is expressed at high levels in several developing projection systems: in neurons of the thalamus, subplate, and lower cortical laminae in the forebrain and in the pontine nucleus, cerebellar granule cells, and Purkinje cells in the hindbrain. Neurotrimin is also expressed at high levels in the olfactory bulb, neural retina, dorsal root ganglia, spinal cord, and in a graded distribution in the basal ganglia and hippocampus. OBCAM has a much more restricted distribution, being expressed at high levels principally in the cortical plate and hippocampus. These results suggest that these proteins, together with other members of this family, provide diversity to the surfaces of different neuronal populations that could be important in the specification of neuronal connectivity.