Marcus L. Martin

Electrocardiography in the patient with the Wolff-Parkinson-White syndrome : Diagnostic and initial therapeutic issues

The Wolff-Parkinson-White syndrome (WPW), estimated to occur in approximately 0.1% to 3% of the general population, is a form of ventricular preexcitation involving an accessory conduction pathway. The definition of WPW relies on the following electrocardiographic features: (1) a PR interval less than 0.12 seconds (2) with a slurring of the initial segment of the QRS complex, known as a delta wave, (3) a QRS complex widening with a total duration greater than 0.12 seconds, and (4) secondary repolarization changes reflected in ST segment-T wave changes that are generally directed opposite (discordant) to the major delta wave and QRS complex changes. The accessory pathway bypasses the atrioventricular (AV) node, creating a direct electrical connection between the atria and ventricles. The majority of patients with preexcitation syndromes remain asymptomatic throughout their lives. When symptoms do occur they are usually secondary to tachyarrhythmias; the importance of recognizing this syndrome is that these patients may be at risk to develop a variety of supraventricular tachyarrhythmias which cause disabling symptoms and, in the extreme, sudden cardiac death. The tachyarrhythmias encountered in the WPW patient include paroxysmal supraventricular tachycardia (both the narrow QRS and wide QRS complex varieties), atrial fibrillation, atrial flutter, and ventricular fibrillation. Diagnostic and urgent, initial therapeutic issues based on initial electrocardiographic information are presented via 5 illustrative cases.

A comparison of 12- and 15-lead ECGs in ED chest pain patients: Impact on diagnosis, therapy, and disposition☆

The objective of this study was to investigate the diagnostic and therapeutic impact of the 15-lead electrocardiogram (15ECG) on the emergency department (ED) management of chest pain (CP) patients. The design was prospective use of 15ECG with real-time physician survey and retrospective comparison to 12-lead ECG (12ECG). The study took place in a University hospital ED. Adult CP patients participated. During the 15ECG period (June 1996 to July 1996), 595 patients (92% of CP patients) had 15ECG analysis. Diagnoses of acute coronary ischemic syndromes (ACIS) were as follows: 13 acute myocardial infarction (AMI, 7 anterior [ANT], 5 inferior [INF], 1 lateral [LAT], 2 posterior [POST], 1 right ventricular [RV]) and 136 unstable angina (USA) with 47% exhibiting ECG abnormality; the 2 POST and 1 RV AMI occurred in the setting of coexisting INF AMI. The following management strategies were used: 6 fibrinolytic therapy (TT), 4 primary angioplasty (PTCA), 67 rule-out myocardial infarction (ROMI), and 144 admission to critical care unit (CCU). During the 12ECG period (June 1995 to July 1995), 599 patients were encountered. The diagnoses of ACIS were as follows: 11 AMI (5 ANT, 4 INF, 2 LAT) and 146 USA with 51% exhibiting ECG abnormality (P = NS for diagnostic comparisons to 15ECG). The following management strategies were used: 5 TT, 5 PTCA, 59 ROMI, and 137 admission to CCU (P = NS for all treatment comparisons to 15ECG). Of 15ECG cases 81% had completed real-time physician survey, showing that the diagnosis and management ACIS were not altered by the 15ECG; physicians felt, however, that the 15ECG provided a more complete anatomic picture of the ACIS. No false-positive cases of additional lead STE were noted in this investigation except in cases involving abnormal intraventricular conduction such as the bundle branch block scenario. The 15ECG provided a more complete description of myocardial injury without altering the ED diagnosis, ED-based therapy, or hospital disposition in adult CP patients. Further study is required to identify patient subset(s) which may benefit from the 15ECG.

A global inventory of hospitals using powder-free gloves: a search for principled medical leadership

Scientific experimental and clinical studies have demonstrated that cornstarch on surgical and examination gloves promotes disease by acting as a reactive foreign body in tissue and serving as a vector for latex allergy. Consequently, hospitals have selected an innovative glove selection program utilizing only powder-free gloves. Healthcare workers in emergency medical systems are now wearing powder-free, latex-free gloves to care for the growing number of patients sensitized to latex. A global Internet search has now identified 70 hospitals in the United States and three hospitals in Europe that use only powder-free gloves.

A Simulation Course on Lifesaving Techniques for Third-year Medical Students

Background: The University of Virginia School of Medicine discontinued animal vivisection in February 2004 for teaching lifesaving procedures to third-year medical students. Consequently, a 1-day course using simulation technology was developed to meet objectives previously covered in the animal laboratory. The authors sought to evaluate the course and hypothesized that the students’ confidence in lifesaving procedures as well as their acceptance of simulation technology as a teaching tool would increase. Methods: The course was designed in a two-session format. The first session (first half of the day) concentrated on individual procedure skills, utilizing part-task trainers. The second session (second half of the day) used a Medical Education Technologies Inc. (METI) Emergency Care Simulator (ECS) full-body patient simulator to present a major trauma scenario. The study design was a prospective, pretest-posttest study without a control group. A 10-question pre and post survey used a Likert scale to explore students’ confidence in their skills as well as their acceptance of simulation technology. A course evaluation used a similar Likert scale for evaluation of the course substations, the trauma scenario, and students’ self-assessment of their skill levels as well as a 100% point scale for an overall rating of the course. Results: A total of eight 1-day courses were successfully held over 2 years with a total enrollment of 240 students utilizing 20 instructors inclusive of faculty, residents, and other emergency medicine health care providers. For the pre and post survey results, there was a significant increase in students’ confidence in performing lifesaving procedures as well as their acceptance of simulation as a teaching tool (P < 0.05 for each question with pre n = 222 and post n = 226). For the course evaluation results (n = 190), all of the course substations were rated in the good to excellent range and the course received an overall score of 97.55 ± 7.23% out of 100%. Furthermore, students reported a significant increase in their skill level (P < 0.05). Conclusion: This lifesaving techniques course utilizing simulation technology successfully covered objectives previously taught with animal vivisection, increased students’ confidence levels in performing lifesaving procedures and was highly accepted by the medical students.

The Design and Evaluation of a Computerized and Physical Simulator for Training Clinical Prostate Exams

The most effective screening for prostate cancer combines the prostate specific antigen blood test with the digital rectal examination (DRE). In performing a DRE, two sequential tasks are completed: ( task a) palpating the prostate to identify abnormalities and ( task b) linking identified abnormalities to a disease diagnosis. At present, clinicians find too few abnormalities and have variable rates of detection, due in part to the inadequacy of training simulators. The Virginia Prostate Examination Simulator (VPES) was designed, built, and tested to address the inadequacies of current simulators by incorporating the design requirements of the basic elements of accurate anatomy, multiple and reconfigurable scenarios of graded difficulty, and technique and performance feedback. We compared the training effectiveness of the VPES with two commercial simulators in an experiment of 36 medical and nurse practitioner students. Results indicate each type of training simulator-improved abilities, in general. Upon closer analysis, however, the following key patterns emerge: 1) Across all types of training, more deficiencies lie in skill-based rather than rule-based decision making, which improves only for VPES trainees; 2) only VPES training transfers both to other simulators and previously unencountered scenarios; 3) visual feedback may increase the number of abnormalities reported yet hinder the ability to discriminate; and 4) applied finger pressure did not correlate with the ability to identify abnormalities.

Interpreter Services in Emergency Medicine

Emergency physicians are routinely confronted with problems associated with language barriers. It is important for emergency health care providers and the health system to strive for cultural competency when communicating with members of an increasingly diverse society. Possible solutions that can be implemented include appropriate staffing, use of new technology, and efforts to develop new kinds of ties to the community served. Linguistically specific solutions include professional interpretation, telephone interpretation, the use of multilingual staff members, the use of ad hoc interpreters, and, more recently, the use of mobile computer technology at the bedside. Each of these methods carries a specific set of advantages and disadvantages. Although professionally trained medical interpreters offer improved communication, improved patient satisfaction, and overall cost savings, they are often underutilized due to their perceived inefficiency and the inconclusive results of their effect on patient care outcomes. Ultimately, the best solution for each emergency department will vary depending on the population served and available resources. Access to the multiple interpretation options outlined above and solid support and commitment from hospital institutions are necessary to provide proper and culturally competent care for patients. Appropriate communications inclusive of interpreter services are essential for culturally and linguistically competent provider/health systems and overall improved patient care and satisfaction.

Quantifying Palpation Techniques in Relation to Performance in a Clinical Prostate Exam

This paper seeks to quantify finger palpation techniques in the prostate clinical exam, determine their relationship with performance in detecting abnormalities, and differentiate the tendencies of nurse practitioner students and resident physicians. One issue with the digital rectal examination (DRE) is that performance in detecting abnormalities varies greatly and agreement between examiners is low. The utilization of particular palpation techniques may be one way to improve clinician ability. Based on past qualitative instruction, this paper algorithmically defines a set of palpation techniques for the DRE, i.e., global finger movement (GFM), local finger movement (LFM), and average intentional finger pressure, and utilizes a custom-built simulator to analyze finger movements in an experiment with two groups: 18 nurse practitioner students and 16 resident physicians. Although technique utilization varied, some elements clearly impacted performance. For example, those utilizing the LFM of vibration were significantly better at detecting abnormalities. Also, the V GFM led to greater success, but finger pressure played a lesser role. Interestingly, while the residents were clearly the superior performers, their techniques differed only subtly from the students. In summary, the quantified palpation techniques appear to account for examination ability at some level, but not entirely for differences between groups.

Simulation framework for training chest tube insertion using virtual reality and force feedback

Most virtual reality simulators are designed for complex medical procedures, such as laparoscopic surgery. While important, these simulators are of use for only a subset of specialized doctors. There is a need for simulators that train clinicians to perform more common procedures, such as chest tube insertion, which all medical students must learn. This work describes the design of a virtual reality simulator that utilizes force feedback devices (SensAble OMNIs) to train the cognitive and motor tasks that underlie the chest tube insertion procedure. The simulators design is focused upon the delivering the examination context rather than emphasizing the material interaction algorithm that governs force feedback. The resultant framework is designed to address issues with current teaching practices. In particular, the design incorporates elements of good teaching style, including repetition, feedback and assessment. Also introduced are two concepts (the grouping and presentation of cognitive tasks in blocks; navigation and status aids) to help trainees more readily learn the examinations numerous steps. The simulated training environment includes a pre-simulation test, vitals monitor, virtual operating room environment, and post performance report.

BALCONY COLLAPSE AT THE UNIVERSITY OF VIRGINIA GRADUATION: WHAT HATH JEFFERSON WROUGHT?

The purpose of this report is to describe the emergency medical response to a disaster caused by the collapse of a balcony in Pavilion I on the Lawn of the University of Virginia during graduation. The emergency medical response to rescue of the injured was hindered by five major factors: (1) a metal linked chain blocked access of rescue vehicles, (2) inability to identify an emergency medical command officer, (3) failure to transfer injured patients with stable vital signs and secured to backboards to a triage area away from the scene of the accident, (4) ineffective crowd control, and (5) the failure to delay procession until completion of patient transport from the disaster site. Sixteen people were injured in the accident and one patient died. The cause of the accident was the absence of a redundant architectural support system for the balcony.

Using a Prostate Exam Simulator to Decipher Palpation Techniques that Facilitate the Detection of Abnormalities Near Clinical Limits

Introduction: Prostate carcinoma (and other prostate irregularities and abnormalities) is detected in part via the digital rectal examination. Training clinicians to use particular palpation techniques may be one way to improve the rates of detection. Methods: In an experiment of 34 participants with clinical backgrounds, we used a custom-built simulator to determine whether certain finger palpation techniques improved one’s ability to detect abnormalities smaller in size and dispersed as multiples over a volume. The intent was to test abnormality cases of clinical relevance near the limits of size perceptibility (ie, 5-mm diameter). The simulator can present abnormalities in various configurations and record finger movement. To characterize finger movement, four palpation techniques were quantitatively defined (global finger movement, local finger movement, average intentional finger pressure, and dominant intentional finger frequency) to represent the qualitative definitions of other researchers. Results: Participants who used more thorough patterns of global finger movement (V and L) ensured that the entire prostate was searched and detected more abnormalities. A higher magnitude of finger pressure was associated with the detection of smaller abnormalities. The local finger movement of firm pressure with varying intensities was most indicative of success and was required to identify the smallest (5-mm diameter) abnormality. When participants used firm pressure with varying intensities, their dominant intentional finger frequency was about 6 Hz. Conclusions: The use of certain palpation techniques does enable the detection of smaller and more numerous abnormalities, and we seek to abstract these techniques into a systematic protocol for use in the clinic.