Accuracy of duplex ultrasonography in estimation of severity of peripheral vascular disease.

Duplex ultrasonography (DUS) is a safe, noninvasive method for imaging vasculature when compared with conventional angiography. Our goal is to assess the accuracy of DUS compared with angiography of the lower extremities. We reviewed a total of 373 lesions in 278 patients from July 2005 through June 2010. Patients underwent DUS followed by angiography within 30 days. Peak systolic velocities (PSV) were stratified into one of four categories and compared with the angiographic findings. Seventy-five chronic total occlusions were found. Of the remaining 298 lesions, a significant relationship was found between PSV and degree of angiographic stenosis (p < 0.001). DUS was found to demonstrate a sensitivity of 79.7%, specificity of 79.2%, positive predictive value of 88.2%, and negative predictive value of 66.7% for lesions ≥ 70%. The 66.7% of the false-negative lesions with the lowest velocities were below the knee joint. DUS of the lower extremities is accurate in determining the degree of stenosis ranging from mild-to-severe disease. Some limitation may exist in estimating the degree of stenosis below the knee.

Paramedic electrocardiogram and rhythm identification: a convenient training device.

INTRODUCTION: A common reason for utilizing local paramedics and the emergency medical services is for the recognition and immediate treatment of chest pain, a complaint that has multiple possible etiologies. While many of those complaining of disease processes responsible for chest pain are benign, some will be life-threatening and will require immediate identification and treatment. The ability of paramedics to not only perform field electrocardiograms (ECGs), but to accurately diagnose various unstable cardiac rhythms has shown significant reduction in time to specific treatments. Increasing the overall accuracy of ECG interpretation by paramedics has the potential to facilitate early and appropriate treatment and decrease patient morbidity and mortality. METHODS: A convenient training device (flip book) on ambulances and in common areas in the fire station could improve field interpretation of certain cardiac rhythms. This training device consists of illustrated sample ECG tracings and their associated diagnostic criteria. The goal was to enhance the recognition and interpretation of ECGs, and thereby, reduce delays in the initiation of treatment and potential complications associated with misinterpretation.This study was a prospective, observational study using a matched pre-test/post-test design. The study period was from November 2008 to December 2008. A total of 136 paramedics were approached to participate in this study. A pre-test consisting of 15 12-lead ECGs was given to all paramedics who agreed to participate in the study. Once the pre-tests were completed, the flip books were placed in common areas. Approximately one month after the flip books were made available to the paramedics, a post-test was administered.Statistical comparisons were made between the pre- and post-test scores for both the global test and each type of rhythm. RESULTS: Using these data, there were no statistically significant improvements in the global ECG interpretation or on individual rhythm interpretations. CONCLUSIONS: A flip book with multiple ECG rhythms and definitions without the benefit of any outside support was not effective in improving paramedic identification of ECG rhythms on a post-test. Suggestions for further research include repeating the study with a larger sample size; utilizing a lecturer to explain how to use the flip book in the most efficient manner; reiterating how to read and interpret ECGs; and answering questions. Comparing test scores of paramedic students, and newly certified paramedics as opposed to veteran paramedics also may indicate that the flip books are more suited for one group over another.

Oral prostaglandin e1 in combination with sodium bicarbonate and normal saline in the prevention of contrast-induced nephropathy: a pilot study.

The purpose of this study was to evaluate the use of prostaglandin E1 (PGE1) as a renal protective medication for patients exposed to contrast agents, as well as to demonstrate the safety, efficacy, and low side-effect profile of PGE1. A prospective, randomized, double-blind study was designed to compare combination of intravenous sodium bicarbonate, normal saline, and oral PGE1 200 µg versus the combination and placebo for renal protection from contrast agents. All patients receiving nonionic contrast during their interventional procedure were eligible for enrollment. Creatinine levels were recorded before and after the administration of contrast and renal protective medications. Contrast-induced nephrotoxicity (CIN) was defined as an increase of 0.5 mg/dL or greater in creatinine level, or an increase of 25% or more above baseline. Age, gender, total amount of contrast used, and incidence of renal failure requiring dialysis were recorded. We conducted the study on 41 patients. Of these, 20 patients received PGE1 and 21 received the placebo. The study group comprised 29 males and 12 females. Diabetes mellitus occurred in 41.5% of the cases (including 40% of PGE1 and 43% of placebo patients). Average contrast use was 77.2 mL (range, 15 to 200 mL). Mean age of the groups was 67.2 years. Average baseline creatinine level was 1.17. The differences between the groups were not statistically significant. CIN by definition occurred in one patient, who received the placebo. Incidence of new onset renal failure requiring dialysis was zero. Postcontrast change in creatinine level for the study was 0.11. There was a change in the creatinine level of 0.161 in the PGE1 group and 0.061 in the placebo group; an improvement of 0.10. PGE1 was not effective in significantly altering postcreatinine levels (p = 0.176). None of the patients enrolled in the study suffered any side effects from taking the PGE1 tablet. Although preliminary, this study shows that the addition of PGE1 for the prevention of CIN is well-tolerated by patients and is a safe modality. Additional studies are required to evaluate efficacy.

Eschar with cellulitis as a clinical predictor in community-acquired methicillin-resistant Staphylococcus aureus (MRSA) skin abscess.

This study was designed to determine the validity of a central eschar with surrounding cellulitis as a clinical predictor for CA-MRSA infection. In this 10-month prospective observational study, patients with a chief complaint or clinical findings of skin infection with abscess had study data sheets placed on their chart. All abscesses were treated with incision and drainage, and wound cultures were obtained. Exclusionary criteria included patient age under 18 years, recently incarcerated within 14 days, and hospitalized or in a nursing home within 10 days. Correlation of wound culture results with recorded physical examination determined the sensitivity, specificity, and positive/negative predictive values. A total of 224 patients with abscesses were enrolled; 18 patients met exclusion criteria. An additional 78 patients were excluded because no wound cultures had been obtained, study data form was incomplete, or there was no evidence of wound cellulitis. Of the 128 remaining patients, 91 wound cultures grew MRSA (71% prevalence). Of these 91 cases, 50 tested positive for central black eschar, yielding a sensitivity of 55% (95% confidence interval [CI] 0.45-0.65). Thirty-seven patients had abscesses that grew non-MRSA bacteria. Three of these were positive for central black eschar, yielding a specificity of 92% (95% CI 0.83-1.01). The positive predictive value was 94% (95% CI 0.88-1.01) and the negative predictive value was 45% (95% CI 0.32-0.59). A central black eschar with cellulitis has good specificity and high positive predictive value in diagnosing CA-MRSA infection.

Computed tomographic angiography versus conventional angiography for the diagnosis of blunt cerebrovascular injury in trauma patients.

BACKGROUND: Blunt cerebrovascular injuries (BCVI) in trauma patients are rare but potentially devastating injuries, particularly if the diagnosis is delayed. Conventional angiography (CA) has been the screening and diagnostic modality of choice for identifying BCVI. With the advent of high-resolution computed tomography (CT), CT angiography has become a common modality for the screening of BCVI. A liberalized screening approach has suggested that cerebrovascular injuries are missed in many patients; however, no standard BCVI screening protocol exists. Early diagnosis of the BCVI can prevent long-term sequelae. METHODS: In this prospective study, all patients received a CT angiogram (16-slice or 64-slice) at the time of injury assessment and followed 24 hours to 48 hours later with CA of the cerebrovasculature. RESULTS: A total of 158 patients were enrolled in the study. CA identified 32 injuries to the cerebrovasculature in 27 patients; CT detected only 13 true injuries (40.6%) in 12 patients. Of the 32 injuries, 11 were carotid artery injuries and 21 were of the vertebral artery. Seventy-four patients were screened with the 16-slice CT scanner with an overall sensitivity of 29%, and 84 patients were screened with the 64-slice CT scanner with an overall sensitivity of 54%. The combined specificity and sensitivity of 16- and 64-slice CT in detecting BCVI were 0.97 (95% confidence interval: 0.92-0.99) and 0.41 (95% confidence interval: 0.22-0.61), respectively. CONCLUSION: Neither 16- nor 64-slice CT angiography is as accurate as CA as a screening tool for BCVI.

Studying critical values: adverse event identification following a critical laboratory values study at the ohio state university medical center.

No study to date has used laboratory critical values to evaluate variations in patient adverse events. We retrospectively analyzed a database of critical values to determine their distribution by hospital unit over time. The data were drawn from the Ohio State University Medical Center Information Warehouse (Columbus) for a 58-month period. Critical values were plotted over time on statistical control charts and analyzed for unusual peaks in monthly occurrence rates. Chart review of individual patient results yielded several predictor variables for the unusual peaks. Of these, occurrence of patient adverse events was the most relevant independent predictor variable for a month with an unusual number of critical values vs a normal month. This result epidemiologically confirms the basic premise of critical value reporting and suggests that the control-chart method of this type could be a new statistical tool to compare clinical activity of different hospital locations at different times.

Training the perception of Hindi dental and retroflex stops by native speakers of American English and Japanese.

Perception of second language speech sounds is influenced by one's first language. For example, speakers of American English have difficulty perceiving dental versus retroflex stop consonants in Hindi although English has both dental and retroflex allophones of alveolar stops. Japanese, unlike English, has a contrast similar to Hindi, specifically, the Japanese /d/ versus the flapped /r/ which is sometimes produced as a retroflex. This study compared American and Japanese speakers' identification of the Hindi contrast in CV syllable contexts where C varied in voicing and aspiration. The study then evaluated the participants' increase in identifying the distinction after training with a computer-interactive program. Training sessions progressively increased in difficulty by decreasing the extent of vowel truncation in stimuli and by adding new speakers. Although all participants improved significantly, Japanese participants were more accurate than Americans in distinguishing the contrast on pretest, during training, and on posttest. Transfer was observed to three new consonantal contexts, a new vowel context, and a new speaker's productions. Some abstract aspect of the contrast was apparently learned during training. It is suggested that allophonic experience with dental and retroflex stops may be detrimental to perception of the new contrast.

Perceptual invariance of coarticulated vowels over variations in speaking rate.

This study examined the perception and acoustics of a large corpus of vowels spoken in consonant-vowel-consonant syllables produced in citation-form (lists) and spoken in sentences at normal and rapid rates by a female adult. Listeners correctly categorized the speaking rate of sentence materials as normal or rapid (2% errors) but did not accurately classify the speaking rate of the syllables when they were excised from the sentences (25% errors). In contrast, listeners accurately identified the vowels produced in sentences spoken at both rates when presented the sentences and when presented the excised syllables blocked by speaking rate or randomized. Acoustical analysis showed that formant frequencies at syllable midpoint for vowels in sentence materials showed "target undershoot" relative to citation-form values, but little change over speech rate. Syllable durations varied systematically with vowel identity, speaking rate, and voicing of final consonant. Vowel-inherent-spectral-change was invariant in direction of change over rate and context for most vowels. The temporal location of maximum F1 frequency further differentiated spectrally adjacent lax and tense vowels. It was concluded that listeners were able to utilize these rate- and context-independent dynamic spectrotemporal parameters to identify coarticulated vowels, even when sentential information about speaking rate was not available.

Perception and production of lexical tones by 3-year-old, Mandarin-speaking children.

The present study investigated 3-year-old children's perception and production of Mandarin lexical tones in monosyllabic words. Thirteen 3-year-old, Mandarin-speaking children participated in the study. Tone perception was examined by a picture-pointing task, and tone production was investigated by picture naming. To compare children's productions with the adult forms, 4 mothers of the children were asked to say the same set of words to their children in a picture-reading activity. The children's and mothers' productions were low-pass filtered at 500 Hz and 400 Hz, respectively, to eliminate segmental information. Ten Mandarin-speaking judges identified the productions of tones from the filtered speech. Adult productions were more accurately identified than productions of the children. The children perceived the level, rising, and falling tones with relatively high accuracy. The dipping tone posed the greatest difficulty for the children in both perception and production.