Philip Bossart

Demographic and Electrocardiographic Factors Associated With Severe Tricyclic Antidepressant Toxicity

This study was designed to evaluate a historic cohort of pure tricyclic antidepressant overdose patients for factors associated with severe toxicity. Hospitalized tricyclic antidepressant overdose patients were identified by computerized discharge diagnosis (ICD-9 codes). Patients with a serum drug screen positive for tricyclic antidepressants and an emergency department 12-lead electrocardiogram were included in the study. Multiple drug overdoses were excluded. Patients were divided into two groups: minor toxicity (n = 41 and major toxicity (n = 65). Criteria for inclusion in the major toxicity group were the occurrence of seizures, endotracheal intubation, coma, arrhythmias requiring treatment, hypotension, or death. The following were found to be associated with increased likelihood of major toxicity (p less than 0.05): ingestion of amitriptyline (odds ratio (OR) 2.57), age greater than or equal to 30 years (OR 2.56), heart rate greater than or equal to 120 bpm (OR 2.86), serum tricyclic antidepressant level greater than or equal to 800 ng/mL (OR 5.20), terminal 40 ms QRS axis (T40-ms axis) greater than or equal to 135 degrees (OR 2.73), QRS interval greater than or equal to 100 ms (OR 2.74), QRS axis greater than 90 degrees (OR 3.68), and QTc interval greater than 480 ms (OR 3.89). The mean T40-ms axis on the initial ECG was more rightward in the major toxicity group (174 +/- 84 vs 125 +/- 91 degrees, p = 0.006). We conclude that patients with severe tricyclic antidepressant toxicity tended to have a more rightward T40-ms axis than those with minor toxicity and that the presence of the above parameters was associated with an increased likelihood of severe toxicity.

Nifedipine for the relief of renal colic: A double-blind, placebo-controlled clinical trial

Pain from ureteral stones is believed to be due to spasm and hyper-peristalsis of the involved ureter. Nifedipine has been shown to decrease human ureteral spasm in vitro. Conflicting results have been reported concerning the clinical efficacy of nifedipine in relieving acute renal colic. This prospective, double-blind, crossover clinical trial evaluated the acute pain relief obtained in 30 patients who had ureteral stones. All patients had ureteral stones documented either by plain abdominal radiograph (six), intravenous pyelogram (16), or passage of the stone(s) in the urine (eight). Each patient served as his own control. The mean pain relief scores for placebo versus 10 to 20 mg oral nifedipine were 0.7 +/- 1.8 and 1.2 +/- 2.5, respectively, as measured on a visual analogue scale (P = .404). Seven patients received clinically significant relief associated with nifedipine, and three patients received relief from placebo (P = .300). Twenty patients (66%) did not experience clinically significant relief from either treatment. We conclude that nifedipine does not differ significantly from placebo in providing relief from acute renal colic.

Utility of the Emergency Department Observation Unit in Ensuring Stress Testing in Low-Risk Chest Pain Patients

BACKGROUND Recent research has noted low rates of compliance among ED chest pain patients referred for outpatient stress testing. The practice at our institution, a 39,000 visits per year emergency department (ED), is to place chest pain patients considered low risk for acute coronary syndrome in an observation unit for serial biomarker testing and provocative cardiac testing. Our objective was to determine the rates of positive stress tests among this group and to extrapolate from this the potential missed positive stress tests if these patients were referred instead for outpatient stress testing. METHODS This was a retrospective chart review of all chest pain patients admitted to the ED observation unit between April 2006 and June 2007. Baseline information, including a history of coronary disease, was recorded. Patients underwent a treadmill stress test, nuclear stress test, or coronary CT scan at the discretion of the attending emergency physician and/or the consulting cardiologist. Rates of positive stress test or coronary CT and patient disposition (admission to an inpatient unit versus discharge for outpatient follow-up) were noted. RESULTS A total of 353 patients underwent stress testing or coronary CT during the study period: 257 (72.8%) patients had an exercise treadmill echocardiogram, 61 (17.3%) patients underwent nuclear stress testing, and 35 (9.9%) patients had a coronary CT. Seventy patients (19.8%) had a history of coronary disease but had been considered appropriate for observation by the attending emergency physician. Thirty-nine stress tests were positive (11%) and 11 were indeterminate (3.1%). Among patients with no history of coronary disease, 20 stress tests were positive (7.1%), and 10 were indeterminate (3.5%). Of all patients with a positive stress test, 19 (48.7%) underwent cardiac catheterization and 1 (2.6%) had coronary artery bypass graft. Twenty-one of 39 patients with a positive stress test (54%) were ultimately admitted to an inpatient unit per the recommendation of the consulting cardiologist. Assuming a best-case scenario in which 70% of patients referred for outpatient stress testing actually have the testing done (based on a recent report of outpatient compliance), physicians would miss approximately 3.3% of patients with a positive stress test if these patients were discharged directly from the ED. CONCLUSION Among chest pain patients admitted to an ED observation unit, the rate of positive stress tests was 11%. Approximately 3.3% of patients with positive stress tests may have been missed if these patients were instead referred for outpatient testing.

The comparative risks of bacterial contamination between a venturi atomizer and a positive displacement atomizer.

Introduction This laboratory study determined the incidence of internal contamination of Venturi principle atomizers and positive displacement atomizers exposed to high external concentrations of Staphylococcal aureus (Staph). Methods Atomizer device nozzle tips were immersed into a Staph solution and 1 ml of spray was atomized via compressed wall air (Venturi) or hydraulic pump (positive displacement). The Venturi nozzle was then wiped with 70% isopropyl alcohol while the disposable positive displacement nozzle was replaced. After 30 minutes, 1 ml of atomized fluid was collected and cultured and the process was repeated. After sixteen uses the fluid remaining in the bottles was cultured. The Venturi atomizer also was subjected to a single use trial to determine the location of device contamination. Results Venturi atomizers sprays grew Staph in every case (144/144), while positive displacement atomizer sprays never grew contaminants (0/144; p < 0.0001). At the end of 16 uses, 7/9 of Venturi atomizers had Staph within their medication reservoirs while none (0/9; p = 0.002) existed in the positive displacement atomizers. After a single use of the Venturi atomizer, the medication reservoir, the air lumen and the medication lumen of the nozzle were all contaminated with Staph. Conclusions External bacterial contamination of the atomizer nozzle tip results in internal bacterial contamination of Venturi devices in as little as one use but not of positive displacement devices. These results warrant further investigation to determine whether a risk of cross-contamination exists in a clinical setting.

Low-risk young adult patients with chest pain may not benefit from routine cardiac stress testing: a Bayesian analysis.

INTRODUCTION Low-risk emergency department (ED) chest pain patients with a nondiagnostic electrocardiogram (ECG) and negative cardiac biomarkers are commonly evaluated with cardiac stress testing to detect undiagnosed coronary artery disease. Provocative testing incurs certain costs and may require additional time investment either in the ED or in an observation setting. Recent research has questioned the utility of provocative testing in young adults with negative cardiac biomarkers and nondiagnostic ECG. We sought to evaluate the utility of cardiac stress testing in our population of young adult patients with chest pain. METHODS We performed a retrospective chart review of all chest pain patients aged 40 years and younger who were admitted to our ED observation unit over the 14-month period between April 2006 and May 2007. We included all patients who were admitted to the observation unit for serial biomarkers and provocative testing and had normal or nondiagnostic ECG, no history of coronary disease, and an initial negative troponin. We recorded baseline characteristics and stress test results of these patients and reviewed the patient charts for the 30-day period following discharge to identify repeat hospital visits and adverse events. We used Bayesian analysis to estimate the rate of true-positive stress testing in this population, using the only prior study of unit patients showing as high as 2 of 220 patients testing positive as a prior estimate. RESULTS A total of 36 patients met inclusion criteria; average age was 34.6 years old (range: 22-40 years) and 61% were male. Patient risk factors included hypertension (19%), diabetes (6%), family history (42%), and smoking (44%). All patients had negative serial cardiac biomarkers and a negative treadmill stress echocardiogram. Thirty-day follow-up demonstrated no adverse cardiac events. We performed Bayesian analysis through the addition of the 36 patients to the 220 patients represented by prior data. The posterior probability distribution changed slightly in location and scale gave a median estimated rate of positive stress testing in this population of 1.04% (95% credible interval, 0.24%-2.78%). CONCLUSIONS The population of chest pain patients younger than 40 years with no history of coronary disease, a nondiagnostic ECG, and negative serial biomarkers may not benefit from provocative testing. Our findings complement those reported previously on the limited utility of cardiac stress testing in this population.

Appropriately screened geriatric chest pain patients in an observation unit are not admitted at a higher rate than nongeriatric patients.

OBJECTIVE Observation units may exclude geriatric patients (defined as age >or=65) due to the high rate of observation failure (admission to an inpatient unit) among these patients. We evaluated whether geriatric patients on a chest pain protocol are admitted to an inpatient unit from an emergency department (ED) observation unit at a higher rate than nongeriatric patients. METHODS This was a retrospective chart review of all patients placed in the ED observation unit at the University of Utah Medical Center over a 14-month period from April 2006 to June 2007. The observation unit did not exclude geriatric patients nor did it exclude patients with a history of coronary disease; patients were admitted per the discretion of the attending ED physician. Patient information, including age, date of admission, history of coronary disease (defined as a previous myocardial infarction, stent, or coronary artery bypass graft), and admission to an inpatient unit from the observation unit, was recorded. Decision to admit to an inpatient unit was made by the consulting cardiologist. Results were analyzed using chi2 statistics. RESULTS One hundred thirty-four geriatric patients were admitted to the observation unit under the chest pain protocol during the study period. Seventeen percent of these patients were admitted to an inpatient unit from the observation unit versus 10.7% of the 394 chest pain patients who were under age 65 (P = 0.048). Geriatric patients were more likely to have coronary disease (31.3%) than nongeriatric patients (20.8%; P = 0.013). We then performed a subanalysis on the 404 patients (92 geriatric, 312 nongeriatric) who had no history of coronary disease. Geriatric patients without a history of coronary disease had a 12% inpatient admission rate from the observation unit versus a 7.7% admission rate for nongeriatric patients without a history of coronary disease (P = 0.2). CONCLUSION Geriatric patients without a history of coronary artery disease were admitted to an inpatient unit at a rate consistent with a generally accepted observation failure rate of 10%. When screened appropriately, these patients may be appropriate for chest pain evaluation in the ED observation unit.

Patients with coronary disease fail observation status at higher rates than patients without coronary disease

BACKGROUND Few studies have evaluated emergency department (ED) observation unit chest pain protocols for optimal patient characteristics and admission rates. At our 35 000-visits/y ED, we implemented a chest pain protocol for our observation unit that allowed emergency physicians to admit patients with known coronary artery disease (CAD). METHODS We performed a retrospective chart review of all observation unit patients admitted under the chest pain protocol from April 1, 2006, to May 31, 2007. We compared the outcomes of patients who had a history of CAD with those who did not. RESULTS Five hundred thirty-one patients were admitted to the observation unit under the chest pain protocol for the 14-month study period. Of these patients, 125 (23.5%) had a history of CAD. Patients with a history of CAD had a higher inpatient admission rate ( 24% vs 8.6%; P < .001), higher rate of a positive stress test or positive coronary computed tomographic scan (32.3% vs 6.9%; P < .001), a higher rate of cardiac catheterization (12% vs 5.9%; P = .02), and a higher rate of stent placement or coronary artery bypass graft (CABG) (7.2% vs 2.2%; P = .007). In multivariate analysis, patient history of CAD was an independent predictor of hospital admission (P = .005) and stent placement or CABG (P = .030). CONCLUSION Patients with known CAD who were admitted to the ED observation unit failed observation status (ie, required hospitalization) and had higher rates of positive testing than those without CAD.

Prospective evaluation of an ED observation unit protocol for trauma activation patients

BACKGROUND The University of Utah emergency department (ED) observation unit (EDOU) cares for over 2500 patients each year, with a significant portion of these patients being trauma activation patients. We evaluated the safety and efficacy of our EDOU trauma protocol and described patient characteristics and outcomes of trauma patients managed in an EDOU. METHODS We performed a prospective observational study of all trauma patients admitted to the EDOU over a 1-year period. Patient disposition, interventions, and adverse events during observation were recorded. Thirty-day follow-up was performed by telephone and chart review to evaluate for missed injuries, repeat hospitalizations, or repeat traumatic events. RESULTS A total of 259 trauma patients were admitted to the EDOU during the study period and were contacted at least 30 days after discharge. There were no deaths, intubations, or other adverse events. At 30-day follow-up, there was 1 missed injury, which did not result in an adverse outcome. Ten patients were reevaluated in the ED or required hospitalization for events occurring after their initial EDOU stay but related to their initial trauma evaluation. The inpatient admission rate from the EDOU was 10.4%, and 3.1% of patients reported another traumatic event during the 30-day follow-up period. CONCLUSIONS There were no adverse outcomes in trauma patients admitted to the EDOU, and our inpatient admission rate was within the generally accepted admission rate for patients in observation status. The EDOU appears to be a safe alternative to inpatient admission for the evaluation of minimally injured trauma activation patients.

Observation unit admission as an alternative to inpatient admission for trauma activation patients

Background: At this 35 000 visits/year emergency department (ED) at a level one trauma centre, a trauma protocol was implemented for the ED observation unit. Data on all trauma observation unit admissions were then collected to evaluate for safety, efficiency and admission rates. Methods: A retrospective chart review was performed of all trauma patients in the observation unit during a 14-month period. Exclusion criteria for observation unit admission included: abnormal vital signs, positive focussed abdominal sonography for trauma examination, abnormal ECG, abnormal chest radiograph, abnormal head computed tomography, Glasgow coma score less than 14, or multisystem trauma. Results: 364 trauma patients were admitted to the observation unit. 84.6% were trauma II activations and 3.8% were trauma I activations. There were no deaths, intubations, loss of vital signs or other adverse events. The average length of stay was 12 h 46 minutes and 11.5% of patients were admitted to an inpatient unit. At 30-day follow-up, there were no significant missed injuries. Conclusion: The observation unit is a safe alternative to inpatient admission for the evaluation of the minimally injured trauma activation patient.

EDOU staffing by PAs: what are the effects on patient outcomes?

Objective: An emergency department observation unit (EDOU) opened in April 2006 staffed by physician assistants (PAs) and nurse practitioners (NPs). This study describes the complexity and outcomes of the EDOU patients to determine the effectiveness of staffing by PAs. Methods: A retrospective chart review was performed of chest pain and trauma patients in the EDOU from April 2006 through May 2007. Patient characteristics, length of stay (LOS), and admission rates were recorded. Adverse events were monitored, and trauma patients were followed for 30 days to evaluate for missed injuries. Results: 531 chest pain patients and 364 trauma patients were admitted to the EDOU during the study period. Average chest pain patient LOS was 14 hours and 32 minutes, and 12.2% of patients were admitted from the EDOU to an inpatient unit. For trauma patients, average LOS was 12 hours and 46 minutes, and 11.5% of patients were admitted to an inpatient unit. There were no deaths, intubations, or loss of vital signs. In 30‐day follow‐up, there were no significant missed injuries among trauma patients. Conclusion: PAs effectively cared for patients of moderate complexity in the two largest groups of utilizers of the EDOU.