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Biomedical subjects

Theodore C Chan

Publications and source records attributed to Theodore C Chan.

At least 19 recordsLinked to original sources

Ventilatory and metabolic demands during aggressive physical restraint in healthy adults.

We investigated ventilatory and metabolic demands in healthy adults when placed in the prone maximal restraint position (PMRP), i.e., hogtie restraint. Maximal voluntary ventilation (MVV) was measured in seated subjects (n=30), in the PMRP, and when prone with up to 90.1 or 102.3 kg of weight on the back. MVV with the heaviest weight was 70% of the seated MVV (122+/-28 and 156+/-38 L/min, respectively; p<0.001). Also, subjects (n=27) were placed in the PMRP and struggled vigorously for 60 sec. During the restrained struggle, ventilatory function (V(E)/ MVV) was 44% of MVV in the resting PMRP. While prone with up to 90.1 or 102.3 kg on the back, the decrease in MVV was of no clinical importance in these subjects. Also, while maximally struggling in the PMRP, V(E) was still adequate to supply the ventilatory needs.

Adult↗

Impact of the San Diego Serial Inebriate Program on use of emergency medical resources.

STUDY OBJECTIVE: We determine the impact of a treatment strategy called the San Diego Serial Inebriate Program on the use of emergency medical services (EMS) and emergency department (ED) and inpatient services by individuals repeatedly arrested for public intoxication. METHODS: This was a retrospective review of health care utilization records (EMS, ED, and inpatient) of 529 individuals from 2000 to 2003. Judges offered individuals a 6-month outpatient treatment program in lieu of custody (Serial Inebriate Program). Demographics and health care utilization are reported overall and by treatment acceptance. RESULTS: From 2000 to 2003, 308 of 529 (58%) individuals were transported by EMS 2,335 times; 409 of 529 (77%) individuals amassed 3,318 ED visits, and 217 of 529 (41%) individuals required 652 admissions, resulting in 3,361 inpatient days. Health care charges totaled $17.7 million (EMS, $1.3 million; ED, $2.5 million; and inpatient, $13.9 million). Treatment was offered to 268 individuals, and 156 (58%) accepted. Use of EMS, ED, and inpatient services declined by 50% for clients who chose treatment, resulting in an estimated decrease in total monthly average charges of $5,662 (EMS), $12,006 (ED), and $55,684 (inpatient). There was no change in use of services for individuals who refused treatment. There was a significant increasing trend in acceptance among individuals with longer jail sentences (<0.001). Treatment acceptance was 20% among those with sentences of 0 to 30 days and reached 63% for those with sentences longer than 150 days. Operational costs and alternate care at clinics and nonparticipating hospitals were not analyzed. CONCLUSION: This community-supported treatment strategy reduced the use of EMS, ED, and inpatient resources by individuals repeatedly intoxicated in public.

Adult↗

Electronic pacemakers.

The number of patients who have cardiac pacemakers has increased markedly over the past few decades since the technology was first introduced in the 1950s. Advances in technology, expanding indications, and the aging of the population ensure that clinicians will encounter patients with cardiac pacemakers on a regular basis. This article summarizes the electrocardiographic manifestations of the normally functioning permanent cardiac pacemaker and abnormalities associated with pacemaker malfunction.

Cardiac Pacing, Artificial↗

Peripheral venous cutdown.

Timely establishment of vascular access is a critical component of the care of the acutely ill or injured patient. Peripheral venous cutdown, once a mainstay in the care of the severely traumatized patient, has progressively lost favor since the introduction of the Seldinger technique of central venous line placement. In fact, recent editions of the Advanced Trauma Life Support (ATLS) text refer to saphenous venous cutdown as an optional skill to be taught at the discretion of the instructor. In certain patients, percutaneous vascular access may be impossible to achieve or result in unacceptable time delays. In these situations, the ability to rapidly and proficiently perform peripheral venous cutdown techniques may prove invaluable and potentially lifesaving. This article reviews the anatomy of the most common sites used for peripheral venous cutdown, peripheral venous cutdown techniques, and the complications associated with peripheral venous cutdown.

Catheterization↗

Impact of rapid entry and accelerated care at triage on reducing emergency department patient wait times, lengths of stay, and rate of left without being seen.

STUDY OBJECTIVE: Patients who leave before being seen by a physician represent a significant problem for many emergency departments (EDs). We sought to determine the effect of a new ED rapid entry and accelerated care at triage (REACT) process on the frequency of patients who leave before being seen. METHODS: We conducted a before-after intervention design to study the effect of REACT for ambulatory patients presenting to our urban academic center ED with a census of approximately 37,000. This process redesign included patient identification tracking, integrated computer interfaces to eliminate up-front registration tasks, immediate placement of patients in open ED beds, and physician-directed ancillary testing and care at triage when no ED beds were available. Outcome measures included the average monthly rate of patients who left before being seen during the 6 months before (pre-REACT) and 6 to 12 months after (post-REACT) its initiation. Other measures included average of mean monthly rates of wait times, ED length of stay, ED census, and admissions. RESULTS: There was a significant decrease in leave before being seen frequency from the pre-REACT to post-REACT periods (3.2% absolute decrease [95% confidence interval (CI) 1.9% to 4.6%]), despite an overall increase in ED census. Average mean monthly patient wait times decreased by 24 minutes [95% CI 10 to 38 minutes] after the initiation of REACT, as did overall ED length of stay by 31 minutes [95% CI 6 to 57 minutes]. CONCLUSION: The initiation of a rapid entry and accelerated care process significantly decreased patient leave before being seen rates, average wait times and length of stay, despite an overall increase in patient census.

Ambulatory Care↗

The inadvertent administration of anticoagulants to ED patients ultimately diagnosed with thoracic aortic dissection.

OBJECTIVES: Aortic dissection (AD) may present similarly to acute coronary syndrome or pulmonary embolus; however, anticoagulation may be detrimental to patients with AD. METHODS: Clinical data were abstracted from medical records of emergency department (ED) patients with nontraumatic AD. Patients administered with anticoagulants were compared with non-anticoagulated patients with regard to presenting symptoms, chest radiograph and electrocardiogram (ECG) findings, and outcome. RESULTS: A total of 44 ED patients with nontraumatic AD was identified over a 4-year period; anticoagulants were administered to 9 (21%). Anticoagulated patients had a higher incidence of chest pain without back pain (78% vs 23%; P = .002) and ST elevations or depressions on ECG (89% vs 6%; P < .001) and were less likely to have a widened mediastinum on chest radiograph (0% vs 67%; P < .001). Two ED anticoagulated patients died, one required a second surgery for bleeding complications, and another suffered a stroke after reversal of anticoagulation. CONCLUSIONS: There is a clinically significant incidence of anticoagulation administration to ED patients ultimately diagnosed with AD, especially in the presence of ambiguous ECG and radiographic findings.

Aged↗

The three-phase model of cardiac arrest as applied to ventricular fibrillation in a large, urban emergency medical services system.

BACKGROUND: Cardiac arrest is responsible for significant morbidity and mortality, with consistently poor outcomes despite the rapid availability of prehospital personnel for defibrillation attempts in patients with ventricular fibrillation (VF). Recent evidence suggests a period of cardiopulmonary resuscitation (CPR) prior to defibrillation attempts may improve outcomes in patients with moderate time since collapse (4-10 min). OBJECTIVES: To determine cardiac arrest outcomes in our community and explore the relationship between time since collapse, performance of bystander CPR, and survival. METHODS: Non-traumatic cardiac arrest data were collected prospectively over an 18-month period. Patients were excluded for: age <18 years, a "Do Not Attempt Resuscitation" (DNAR) directive, determination of a non-cardiac etiology for arrest, and an initially recorded rhythm other than VF. Patients were stratified by time since collapse (<4, 4-10, > 10 min, and unknown) and compared with regard to survival and neurological outcome. In addition, patients with and without bystander CPR were compared with regard to survival. RESULTS: : A total of 1141 adult non-traumatic cardiac arrest victims were identified over the 18-month study period. This included 272 patients with VF as the initially recorded rhythm. Of these, 185 had a suspected cardiac etiology for the arrest; survival to hospital discharge was 15% in this group, with 82% of these having a good outcome or only moderate disability. Survival was highest among patients with time since collapse of less than 4 min and decreased with increasing time since collapse. There were no survivors among patients with time since collapse greater than 10 min. Among patients with time since collapse of 4 min or longer, survival was significantly higher with the performance of bystander CPR; there was no survival advantage to bystander CPR among patients with time since collapse less than 4 min. CONCLUSIONS: The performance of bystander CPR prior to defibrillation by EMS personnel is associated with improved survival among patients with time since collapse longer than 4 min but not less than 4 min. These data are consistent with the three-phase model of cardiac arrest.

Aged↗

Evaluation of pediatric glucose monitoring and hypoglycemic therapy in the field.

As specific indications for glucose monitoring in pediatric patients are not standardized, we sought to evaluate our EMS system regarding the use of this test, so that objective data can be used for prehospital provider education. We performed a 5-year electronic search of prehospital records to assess pediatric patients who had glucose monitoring performed, with subgroup analysis on those requiring therapy. We found that 6018 pediatric patients received glucose monitoring with the most common chief complaints for testing including: seizure, "other medical," trauma head/neck, and OD/poisoning. Of these, 270 (4.5%) required therapy for hypoglycemia with an additional 100 (1.7%) patients receiving treatment without use of the paramedic's monitor. Age breakdowns for therapy were as follows: 0-4 years, 44 (11.9%); 5-9, 36 (9.7%); 10-14, 58 (15.7%); 15-19, 232 (62.7%). In the prehospital setting, the need to treat hypoglycemia in pediatric patients is infrequent. The chief complaints associated with the highest frequencies of hypoglycemia are seizures and altered neurologic status.

Adolescent↗

An Intelligent 802.11 Triage Tag for medical response to disasters.

When medical care is initiated at a mass casualty event, the first activity is the triage of victims, which is the grouping by victims severity of injury. Paper triage tags are often used to mark victims' triage status and to record information on injuries and treatments administered in the field. In this paper we describe the design and development of an"Intelligent Triage Tag" (ITT), an electronic device to coordinate patient field care. ITTs combine the basic functionality of a paper triage tag with sensors, nonvolatile memory, a microprocessor and 802.11 wireless transmission capabilities. ITTs not only display victims' triage status but also signal alerts, and mark patients for transport or immediate medical attention. ITTs record medical data for later access offsite and help organize care by relaying information on the location of the victims during field treatment. ITTs are a part of the Wireless Information System for Medical Response in Disasters (WIISARD) architecture.

Disasters↗

Role-tailored software systems for medical response to disasters: enhancing the capabilities of "mid-tier" responders.

WIISARD (Wireless Internet Information System for Medical Response in Disasters) is developing wireless technology to coordinate and enhance the care of mass casualties at disaster sites. Mid-tier personnel (area supervisors) play a critical role in disaster response, supervising care processes in the triage, Treatment and Transport areas of the attack site. The design of a software tool to support mid-tier activities focuses on providing supervisors aggregate information on patient conditions and needs, real-time data on ambulance availability and location, and hospital status and on coordinating care delivery among triage, treatment and transport areas.

Computer Systems↗

Community trial to decrease ambulance diversion hours: the San Diego county patient destination trial.

STUDY OBJECTIVE: Emergency department (ED) ambulance diversion is a major issue in many communities. When patients do not reach requested facilities, challenges in care are compounded by lack of available medical records and delays in transferring admitted patients back to the originally requested facility. We seek to evaluate a community intervention to reduce ambulance diversion. METHODS: This was a community intervention in a county of 2.8 million individuals. Ambulance diversion guidelines were revised for all ambulance agencies and EDs. Participation by EDs was voluntary, and main outcome measures, which included ambulance transports, ambulance diversions, and bypass hours, were compared for the pretrial, trial, and posttrial periods. RESULTS: A total of 235,766 patients were transported to an ED by advanced life support ambulance during the 2-year study period. There was a significant decrease in the number of patients who did not reach the requested facility because of ambulance diversion for the trial period (n=322) and posttrial period (n=449) compared with the pretrial period (n=1,320; -998 diverted patients per month [95% confidence interval (CI) -1,162 to -833 patients] and -871 diverted patients per month [95% CI -963 to -780 patients], respectively). There was also a significant decrease in average monthly hours on diversion for the trial period (n=1,079) and posttrial period (n=1,774) compared with the pretrial period (n=4,007; -2,928 hours on bypass [95% CI -3,936 to -1,919 hours on bypass] and -2,232 hours on bypass [95% CI -3,620 to -2,235 hours on bypass], respectively). CONCLUSION: A voluntary community-wide approach to reducing hospital ED diversion and getting more ambulance patients to requested facilities was effective.

Adolescent↗

The clinical presentation and impact of diagnostic delays on emergency department patients with spinal epidural abscess.

Previous reports have recommended the use of a "classic triad" of fever, spine pain, and neurologic deficits to diagnose spinal epidural abscess (SEA); however, the prognosis for complete recovery is poor once these deficits are present. This retrospective case-control study investigates the impact of diagnostic delays on outcome and explores the use of risk factor screening for early identification of SEA in a population of ED patients. Inpatients with a discharge diagnosis of SEA and a related ED visit before the admission were identified over a 10-year time period. In addition, a pool of ED patients presenting with a chief complaint of spine pain was generated; controls were hand-matched 2:1 to each SEA patient based on age and gender. Data regarding demographics, presence of risk factors, physical examination findings, laboratory and radiographic results, and clinical outcome were abstracted from medical records and entered into a database for further analysis. Patients with SEA were compared to matched controls with regard to the prevalence of risk factors and the "classic triad." We also explored the impact on outcome of diagnostic delays, defined as either: 1) multiple ED visits before diagnosis, or 2) admission without a diagnosis of SEA and >24 h to a definitive study. A total of 63 SEA patients were hand-matched to 126 controls with spine pain. Diagnostic delays were present in 75% of SEA patients. Residual motor weakness was present in 45% of these patients vs. only 13% of patients without diagnostic delays (odds ratio 5.65, 95% C.I. 1.15-27.71, p < 0.05). The "classic triad" of spine pain, fever, and neurologic abnormalities was present in 13% of SEA patients and 1% of controls during the initial visit (p < 0.01); one or more risk factors were present in 98% of SEA patients and 21% of controls (p < 0.01). The erythrocyte sedimentation rate (ESR) was more sensitive and specific than total white blood cell (WBC) count as a screen for SEA. In conclusion, diagnostic delays are common in patients with SEA, often leading to irreversible neurologic deficits. The use of risk factor assessment is more sensitive than the use of the classic diagnostic triad to screen ED patients with spine pain for SEA. The ESR may be a useful screening test before magnetic resonance imaging in selected patients.

Adult↗

Emergency evaluation and treatment of priapism.

Priapism is a fairly uncommon presentation to the Emergency Department, but when it does present, it represents a true urologic emergency. Prompt treatment will decrease the risk of permanent sequelae including impotence. Treatment should be based on etiology and follow an organized approach. Various cases will arise when conservative management will not remedy the priapism and more aggressive measures will be needed, particularly if emergent urological consultation is not available. This article reviews the causes of priapism and systematically reviews techniques and procedures used to manage and treat priapism.

Adrenergic alpha-Agonists↗

Nasal foreign body removal.

Patients with nasal foreign bodies often present to the Emergency Department (ED) for removal. In most cases, successful removal can be performed by the Emergency Physician (EP) using a variety of simple techniques. The EP should be familiar with multiple procedural techniques as a significant number of patients will require multiple attempts and techniques for removal of the nasal foreign body. This article reviews the more common techniques for removal, and provides specific technical tips, indications and contraindications for each technique.

Catheterization↗

Prospective randomized study of viscous lidocaine versus benzocaine in a GI cocktail for dyspepsia.

We hypothesized that Benzocaine (Hurricaine) would work as quickly and effectively as viscous Lidocaine in this preparation. This was a prospective randomized, single-blinded comparison between Benzocaine and Lidocaine as the topical anesthetic in a gastrointestinal (GI) cocktail. Patients 18 years or older were approached for participation when a GI cocktail was ordered by the Emergency Physician. Patients were randomized to equivalent doses of either Benzocaine or viscous Lidocaine in addition to 30 cc of Maalox and 10 cc of Donnatal. Assessment using a visual analog pain scale occurred at time intervals of 0, 5, 15, and 30 min. Eighty-two patients were enrolled (44 to Benzocaine, 38 to viscous Lidocaine), with each group having a statistically significant improvement in pain (p < 0.001). There were no statistical differences between the Benzocaine and viscous Lidocaine groups in terms of the relief of symptoms at each of the assessment times. There were no adverse outcomes in either group.

Adult↗

Electrocardiographic manifestations: acute inferior wall myocardial infarction.

The 12-lead electrocardiogram (EKG) is an important tool in evaluating the patient with acute myocardial infarction (MI). Patients with acute inferior wall myocardial infarction (IWMI) represent a heterogeneous group in terms of morbidity, mortality, Emergency Department (ED) management, and site of occlusion in the culprit coronary artery. The standard 12-lead EKG, right-sided chest leads and posterior chest leads, in conjunction with clinical findings often provide the necessary information for the Emergency Physician (EP) to predict complications, morbidity and mortality. IWMI patients may have associated right ventricular infarction (RVI) or lateral and posterior wall extension. Each of these entities is associated with specific hemodynamic abnormalities and increased mortality. In addition, various atrioventricular (AV) blocks are commonly associated with IWMI. This article presents several cases of IWMI with EKGs and a discussion of EKG interpretation in the setting of IWMI.

Aged↗