Emergency Department compression ultrasound to diagnose proximal deep vein thrombosis.

Emergency Department (ED) patients with suspected deep vein thrombosis (DVT) require an objective vascular study such as ultrasound (US) to confirm the diagnosis prior to treatment or disposition. A simple compression US test of the common femoral vein and popliteal vein reliably detects proximal DVT in symptomatic patients. Application of compression US in the ED by Emergency Physicians (EPs) has been tested in a single previous study. We evaluated the ability of ED compression US, performed by EPs, to diagnose proximal DVT as compared to duplex US performed in a vascular laboratory. A prospective, observational study was conducted on a convenience sample of patients presenting to an ED with lower extremity symptoms and signs suggestive of DVT. Patients with a history of DVT in the symptomatic extremity were excluded. Final diagnosis of DVT was made by color-flow duplex US performed in a vascular laboratory. ED compression US was performed by one of six EP sonographers. In compression US, DVT was diagnosed by the inability to compress the common femoral vein or popliteal vein. The examination was considered indeterminate if the veins could not be clearly identified or compressibility was equivocal. For statistical analysis, an indeterminate examination was considered positive. In those cases where ED compression US was discordant with duplex US, and not indeterminate, we retrospectively reviewed the US findings. There were 76 patients who completed the study, and 18 patients (24%) were diagnosed with DVT by duplex US, among whom ED compression US was positive in 14, negative in 2, and indeterminate in 2. Among 58 patients diagnosed without DVT by duplex US, there were 4 false-positive ED compression US examinations and 10 indeterminate examinations. In all, ED compression US was indeterminate in 12 patients (15.8%). Compared to duplex US, ED compression US had a sensitivity of 88.9% (95% C.I. 65.3-98.6%) and specificity of 75.9% (62.8-86.1). Negative predictive value was 95.7% (85.2-99.5). Among ED patients with the clinical diagnosis of possible DVT, negative ED compression US greatly reduces the likelihood of DVT, such that discharge and outpatient follow-up can be considered. Because of limited specificity, positive results require confirmation, but may justify immediate treatment pending follow-up testing. Indeterminate results can be expected in a significant number of patients and mandate further testing prior to disposition.

Ultrasound-guided brachial and basilic vein cannulation in emergency department patients with difficult intravenous access.

STUDY OBJECTIVE: Emergency department patients who require intravenous access but lack peripheral intravenous sites frequently require central line placement. Blind percutaneous brachial vein cannulation has been proposed as an alternative in these patients but is associated with high failure and complication rates. We evaluated an ultrasound-guided approach to percutaneous deep brachial vein or basilic vein cannulation in ED patients with difficult intravenous access. METHODS: We prospectively enrolled ED patients who required intravenous access in whom there had been 2 unsuccessful attempts at establishing a peripheral intravenous line. Using a 7.5-MHz ultrasound probe, the deep brachial vein or basilic vein was identified and then cannulated with a 2-in, 18- to 20-gauge intravenous catheter. Time from probe placement to cannulation, number of attempts, and complications were recorded. RESULTS: One hundred one patients were enrolled, of whom 50 were injection drug users and 21 were obese. Cannulation was successful in 91 patients (91%) and accomplished on the first attempt in 73 (73%). The mean (+/-SD) time required for cannulation was 77 seconds (+/-129, range 4 to 600 seconds). The line infiltrated or fell out within 1 hour of cannulation in 8 (8%) patients. One patient reported severe pain. There were 2 (2%) cases of brachial artery puncture. CONCLUSION: Ultrasound-guided brachial and basilic vein cannulation is safe, rapid, and has a high success rate in ED patients with difficult peripheral intravenous access.

Prevalence of cardiac valve abnormalities in afebrile injection drug users.

OBJECTIVES: To determine the prevalence of occult valvular pathology in afebrile injection drug users (IDUs) compared with an afebrile, non-IDU population. To characterize the type of valvular pathology present in light of current recommendations regarding periprocedural antibiotic prophylaxis against endocarditis. METHODS: This was a comparative, cross-sectional study involving a convenience sample of 98 patients with a history of injection drug use, and 99 non-IDU patients presenting to a large urban ED. Patients were excluded if they had one or more of the following: a history of cardiac valve abnormality, a history of endocarditis, fever on presentation, or a cardiac murmur. Data were collected that included demographics, medical history, and details of injection drug use. Transthoracic echocardiography (echo) was performed on each subject in the ED, and read in a blinded fashion by a single board-certified cardiologist. RESULTS: Among 98 IDUs and 99 non-IDUs, 12% of the IDUs had aortic valve thickening, compared with 5.1% of the non-IDUs (99% CI for difference of 7.8% = -3.0% to 18.6%). Forty-four percent of the IDUs had mitral valve thickening, compared with 25% of the non-IDUs (99% CI for difference of 18.3% = 0.9% to 35.7%). Eleven percent of the IDUs vs 1% of the non-IDUs had tricuspid valve thickening (99% CI for difference of 10.4% = 1.6% to 19.2%). No patient had pulmonic valve thickening. Six percent of the IDUs vs 0% of the non-IDUs had mitral annulus thickening (99% CI for difference of 6.3% = -0.1% to 12.8%). Twelve percent of the IDUs vs 3% of the non-IDUs had mitral chordae thickening (99% CI for difference of 9.5% = -0.4% to 19.4%). Tricuspid chordae thickening was recorded in 2% of the IDUs vs 0% of the non-IDUs (99% CI for difference of 2.1% = -1.7% to 6.0%). Most important, the prevalence of valvular regurgitation was small, and evenly distributed in the two groups. No valvular vegetations were seen. CONCLUSION: Both non-IDUs and IDUs have occult valvular pathology. There is an increased prevalence in IDUs of tricuspid and mitral valve thickening. The prevalence of valvular regurgitation, a reported indication for periprocedural antibiotic prophylaxis, was small and the affected valves were not statistically different between the two groups. These findings question the selected routine use of antibiotic prophylaxis in IDU patients undergoing invasive procedures.

Diagnostic role of ED ultrasound in deep venous thrombosis and pulmonary embolism.

Proximal deep venous thrombosis (DVT), which may lead to pulmonary embolism (PE), is one of the serious and underrecognized causes of lower extremity pain and swelling. The diagnosis of DVT requires a confirmatory objective test because clinical signs and symptoms are unreliable. Assessment of thigh vein compressibility with real-time ultrasound is an accurate test for DVT that may be performed rapidly at the bedside. Although unproven, we propose that wider use of this test in the emergency department by emergency physicians might increase the diagnosis of DVT, prevent PE, and reduce utilization of other more costly and invasive diagnostic tests. Evaluation of DVT by compression ultrasound may also be incorporated in the diagnostic workup of suspected PE. In the case of a nondiagnostic ventilation/perfusion scan, demonstration of proximal DVT by ultrasound represents a likely source of PE and an indication for anticoagulation, eliminating the need for pulmonary angiography. In the critically ill patient whose presentation is consistent with massive PE, one rapid approach to the diagnosis may be to combine transthoracic echocardiography with lower extremity ultrasound.

Severe metabolic alkalosis due to baking soda ingestion: case reports of two patients with unsuspected antacid overdose.

Oral ingestion of baking soda (sodium bicarbonate) has been used for decades as a home remedy for acid indigestion. Excessive bicarbonate ingestion places patients at risk for a variety of metabolic derangements including metabolic alkalosis, hypokalemia, hypernatremia, and even hypoxia. The clinical presentation is highly variable but can include seizures, dysrhythmias, and cardiopulmonary arrest. We present two cases of severe metabolic alkalosis in patients with unsuspected antacid overdose. The presentation and pathophysiology of antacid-related metabolic alkalosis is reviewed.

Emergency medicine applications of echocardiography.

Echocardiography represents an important, accessible tool in the evaluation of the critically ill emergency department patient. Echocardiography provides anatomic and physiologic information about the cardiovascular system safely and at the bedside. This modality may permit early and more accurate diagnosis and management of a wide range of disease processes while avoiding the risks and costs associated with other diagnostic strategies. It is imperative that emergency department physicians have a working understanding of the applications and limitations of echocardiography to make best use of its considerable patient care potential.

Analysis of emergency department interpretation of electrocardiograms.

The objective of the study was to determine the concordance of emergency physicians' and cardiologists' interpretations of emergency department (ED) electrocardiograms (ECG), to evaluate the impact of ECG misinterpretation on patient management, and to determine error rates as a function of the level of physician training and the specific ECG diagnoses. ECG interpretations were registered prospectively using a programmed-response data sheet. A second blinded interpretation by a staff cardiologist was assumed to be correct. Only ECG discrepancies with potential or probable clinical importance were considered as errors. The ED management of patients with ECG misinterpretations was reviewed by the investigators. The study was performed at an urban university hospital using 300 consecutive ED ECGs. The analysis found 154 errors of interpretation of which nine had probable clinical significance, and 56 had indeterminant significance. The concordance was weak at 0.69 (Kappa = 0.32, weighted Kappa = 0.30) with a significant discordance (McNemar Chi 2:P < 0.05). Error rates did not differ significantly between the diverse categories of physicians. In two cases, interpretation errors impacted patient management decisions but not patient outcomes. The most frequent errors involved repolarization abnormalities, ventricular hypertrophy and hemi-blocks. While discordance was significant, errors in ECG interpretation rarely impacted patient management. Prospective evaluation of ECG interpretation may be a useful means of gauging physician skills. It can also serve to focus educational activities on problem areas in electrocardiography.

Delayed diagnosis of subdural hematoma following normal computed tomography scan.

We report the cases of three patients with subdural hematoma following minor closed-head trauma in whom the initial neurologic examinations and cranial computed tomography (CT) scans were normal. In each case, the patient was re-evaluated clinically several times (average of four times) due to persistence of post-traumatic symptoms. The development of focal neurologic signs, which eventually led to a correct diagnosis, was significantly delayed in all three cases (average of 47 days). All three patients had large subdural hematomas requiring surgical drainage. The timely diagnosis of subdural hematoma may be difficult despite the appropriate use of CT scan in the immediate post-traumatic period. Repeat CT scan may be indicated in patients suffering minor head trauma with persistent symptoms. These patients seem to recover without deficit following neurosurgical treatment despite a significant delay in diagnosis.

Voluntary total fasting in political prisoners--clinical and biochemical observations.

Thirty-three political prisoners on hunger strike (voluntary total fast--VTF) for 6-24 days were admitted to two hospitals in Johannesburg in 1989. They had been detained without trial for 4-32 months. Sound doctor-patient relationships were established by emphasis of the principle of full patient participation in clinical decision-making at every level, by rejection of police interference in patient care, and by refusal to discharge subjects back into detention. Depression and abdominal pains were the predominant symptoms. In 6 lean subjects with complete data the expected initial period of rapid weight loss was not observed. Before hospitalisation most subjects became dehydrated from inadequate fluid intake and an apparent absence of thirst. Serum creatinine concentrations were a better indication of dehydration than serum urea levels. Mild hyponatraemia was found in one-third of patients. Refeeding after 6-27 days of VTF was initiated with a dilute lactose-free formula diet, and was uncomplicated. Close clinical monitoring of subjects during VTF is essential, and it is recommended that prisoners should be admitted to hospital at 10% of weight loss, if not before. The health care of prisoners can best be provided by professionals independent of the police and prison services.

Acute psychosis after amantadine overdose.

Amantadine is an antiviral agent that is also used in the treatment of parkinsonism and neuroleptic-induced extrapyramidal symptoms. Toxic effects of amantadine relate primarily to the central nervous system and range from mild symptoms to disorientation and hallucinations. Anti-cholinergic agents may exacerbate these effects. We report a case of unsuspected amantadine overdose in a previously healthy 35-year-old woman who presented with acute psychosis manifested by delirium and visual hallucinations. Concomitant use of diphenhydramine contributed to the clinical presentation. Amantadine toxicity should be considered in the differential diagnosis of altered mental status in patients known to be taking the drug or with conditions commonly treated with amantadine.