State-by-state estimates of avoidable trauma mortality with early and liberal versus delayed or restricted administration of tranexamic acid.

OBJECTIVE: Early administration of tranexamic acid (TXA) has been shown to save lives in trauma patients, and some U.S. emergency medical systems (EMS) have begun providing this therapy prehospital. Treatment protocols vary from state to state: Some offer TXA broadly to major trauma patients, others reserve it for patients meeting vital sign criteria, and still others defer TXA entirely pending a hospital evaluation. The purpose of this study is to compare the avoidable mortality achievable under each of these strategies, and to report on the various approaches used by EMS. METHODS: We used the National Center for Health Statistics Underlying Cause of Death data to identify a TXA-naïve population of trauma patients who died from 2007 to 2012 due to hemorrhage. We estimated the proportion of deaths where the patient was hypotensive or tachycardic using the National Trauma Data Bank. We used avoidable mortality risk ratios from the landmark CRASH 2 study to calculate lives saved had TXA been given within one hour of injury based on a clinician's gestalt the patient was at risk for significant hemorrhage; had it been reserved only for hypotensive or tachycardic patients; or had it been given between hours one to three of injury, considered here as a surrogate for deferring the question to the receiving hospital. RESULTS: Had TXA been given within 1 hour of injury, an average of 3409 deaths per year could have been averted nationally. Had TXA been given between one and three hours after injury, 2236 deaths per year could have been averted. Had TXA only been given to either tachycardic or hypotensive trauma patients, 1371 deaths per year could have been averted. Had TXA only been given to hypotensive trauma patients, 616 deaths per year could have been averted. Similar trends are seen at the individual state level. A review of EMS practices found 15 statewide protocols that allow EMS providers to administer TXA for trauma. CONCLUSION: Providing early TXA to persons at risk of significant hemorrhage has the potential to prevent many deaths from trauma, yet most states do not offer it in statewide prehospital treatment protocols.

Types of diagnostic errors in neurological emergencies in the emergency department.

BACKGROUND: Neurological emergencies often pose diagnostic challenges for emergency physicians because these patients often present with atypical symptoms and standard imaging tests are imperfect. Misdiagnosis occurs due to a variety of errors. These can be classified as knowledge gaps, cognitive errors, and systems-based errors. The goal of this study was to describe these errors through review of quality assurance (QA) records. METHODS: This was a retrospective pilot study of patients with neurological emergency diagnoses that were missed or delayed at one urban, tertiary academic emergency department. Cases meeting inclusion criteria were identified through review of QA records. Three emergency physicians independently reviewed each case and determined the type of error that led to the misdiagnosis. Proportions, confidence intervals, and a reliability coefficient were calculated. RESULTS: During the study period, 1168 cases were reviewed. Forty-two cases were found to include a neurological misdiagnosis and twenty-nine were determined to be the result of an error. The distribution of error types was as follows: knowledge gap 45.2% (95% CI 29.2, 62.2), cognitive error 29.0% (95% CI 15.9, 46.8), and systems-based error 25.8% (95% CI 13.5, 43.5). Cerebellar strokes were the most common type of stroke misdiagnosed, accounting for 27.3% of missed strokes. CONCLUSIONS: All three error types contributed to the misdiagnosis of neurological emergencies. Misdiagnosis of cerebellar lesions and erroneous radiology resident interpretations of neuroimaging were the most common mistakes. Understanding the types of errors may enable emergency physicians to develop possible solutions and avoid them in the future.

Avoiding misdiagnosis in patients with neurological emergencies.

Approximately 5% of patients presenting to emergency departments have neurological symptoms. The most common symptoms or diagnoses include headache, dizziness, back pain, weakness, and seizure disorder. Little is known about the actual misdiagnosis of these patients, which can have disastrous consequences for both the patients and the physicians. This paper reviews the existing literature about the misdiagnosis of neurological emergencies and analyzes the reason behind the misdiagnosis by specific presenting complaint. Our goal is to help emergency physicians and other providers reduce diagnostic error, understand how these errors are made, and improve patient care.

Klebsiella pneumoniae liver abscess: an emerging problem in North America.

BACKGROUND: Before the 1980s, Escherichia coli was the most common cause of pyogenic liver abscess, but more recently, Klebsiella pneumoniae has emerged as the most common organism in the United States and Taiwan. OBJECTIVE: Our goal is to present a case of K. pneumoniae liver abscess (KLA) and review the risk factors, presenting symptoms, complications, and treatment of this disease that is emerging in North America. CASE REPORT: We present a patient who was found to have KLA complicated by bacteremia and sepsis. CONCLUSIONS: Initially described in the Asian literature, KLA is an emerging problem in North America. We present this case to increase awareness among emergency physicians of the diagnosis, risk factors, potential complications-including bacteremia and disseminated infection-and treatment.

Multicenter study of central venous oxygen saturation (ScvO(2)) as a predictor of mortality in patients with sepsis.

STUDY OBJECTIVE: Abnormal (both low and high) central venous saturation (ScvO(2)) is associated with increased mortality in emergency department (ED) patients with suspected sepsis. METHODS: This was a secondary analysis of 4 prospectively collected registries of ED patients treated with early goal-directed therapy-based sepsis resuscitation protocols from 4 urban tertiary care hospitals. Inclusion criteria were sepsis, hypoperfusion defined by systolic blood pressure less than 90 mm Hg or lactate level greater than or equal to 4 mmol/L, and early goal-directed therapy treatment. ScvO(2) levels were stratified into 3 groups: hypoxia (ScvO(2) <70%); normoxia (ScvO(2) 71% to 89%); and hyperoxia (ScvO(2) 90% to 100%). The primary exposures were initial ScvO(2) and maximum ScvO(2) achieved, with the primary outcome as inhospital mortality. Multivariate analysis was performed. RESULTS: There were 619 patients who met criteria and were included. For the maximum ScvO(2), compared with the mortality rate in the normoxia group of 96 of 465 (21%; 95% confidence interval [CI] 17% to 25%), both the hypoxia mortality rate, 25 of 62 (40%; 95% CI 29% to 53%) and hyperoxia mortality rate, 31 of 92 (34%; 95% CI 25% to 44%) were significantly higher, which remained significant in a multivariate modeling. When the initial ScvO(2) measurement was analyzed in a multivariate model, only hyperoxia was significantly higher. CONCLUSION: The maximum ScvO(2) value achieved in the ED (both abnormally low and high) was associated with increased mortality. In multivariate analysis for initial ScvO(2), the hyperoxia group was associated with increased mortality, but not the hypoxia group. This study suggests that future research aimed at targeting methods to normalize high ScvO(2) values by therapies that improve microcirculatory flow or mitochondrial dysfunction may be warranted.

Favorable response to analgesics does not predict a benign etiology of headache.

BACKGROUND: Distinguishing between primary and secondary headaches (HAs) is essential for the safe and effective management of patients with HA. A favorable response to analgesics may be observed with both classes of HAs and therefore is not a good predictor of who needs further evaluation. OBJECTIVE: To systematically review the data that a favorable response to analgesics including triptans should not be used to exclude a serious secondary cause of HA. DESIGN: PubMed search of English-language articles between 1980 and 2007 and reference lists of these articles. Two authors independently reviewed articles for study results and quality. Inclusion was based on 100% agreement between authors. We included articles that described secondary HAs as (1) having a favorable response to analgesics and/or (2) having a favorable response to sumatriptan. Of the 548 studies identified by our search strategy, 18 were included in our final analysis. RESULTS: Seven of the 18 studies found that 46/103 patients (44%) described a significant or complete resolution of secondary HA from medications such as anti-emetics and nonsteroidal anti-inflammatory drugs (NSAIDs). Eleven of the 18 articles including 25/25 patients (100%) described a significant or complete resolution of secondary HA from sumatriptan, a serotonin 5HT agonist. CONCLUSIONS: A favorable response to analgesics including triptans should not be used to exclude a serious secondary cause of HA.

Innocuous cooling can produce nociceptive sensations that are inhibited during dynamic mechanical contact.

In a previous study of the heat grill illusion, sensations of burning and stinging were sometimes reported when the skin was cooled by as little as 2 degrees C. Informal tests subsequently indicated that these nociceptive sensations were experienced if cooling occurred when the stimulating thermode rested on the skin, but not when the thermode was cooled and then touched to the skin. In experiment 1 subjects judged the intensity of thermal (cold/warm) and nociceptive (burning/stinging) sensations when the volar surface of the forearm was cooled to 25 degrees C (1) via a static thermode (Static condition), or (2) via a cold thermode touched to the skin (Dynamic condition). The total area of stimulation was varied from 2.6 to 10.4 cm(2) to determine if the occurrence of nociceptive sensations depended upon stimulus size. Burning/stinging was rated 10.3 times stronger in the Static condition than in the Dynamic condition, and this difference did not vary significantly with stimulus size. In experiment 2, thermal and nociceptive sensations were measured during cooling to just 31 degrees, 29 degrees or 27 degrees C, and data were obtained on the frequency at which different sensation qualities were experienced. Stinging was the most frequently reported nociceptive quality in the Static condition, and stinging and burning were both markedly reduced in the Dynamic condition. In experiment 3 we tested the possibility that dynamic contact might have inhibited burning and stinging not because of mechanical contact per se, but rather because dynamic contact caused higher rates of cooling. However, varying cooling rate over a tenfold range (-0.5 degrees to -5.0 degrees /s) had no appreciable effect on the frequency of stinging and burning. Overall, the data show that mild cooling can produce nociceptive sensations that are suppressed under conditions of dynamic mechanical contact. The latter observation suggests that cold is perceived differently during active contact with objects than during passive heat loss to the environment. Hypotheses about the physiological basis of the nociceptive sensations at mild temperatures and their possible role in the phenomena of paradoxical heat and synthetic heat are discussed.

A four-channel analysis of the tactile sensitivity of the fingertip: frequency selectivity, spatial summation, and temporal summation.

Thresholds were measured for the detection of vibratory stimuli of variable frequency and duration applied to the index fingertip and thenar eminence through contactors of different sizes. The effects of stimulus frequency could be accounted for by the frequency characteristics of the Pacinian (P), non-Pacinian (NP) I, and NP III channels previously determined for the thenar eminence (Bolanowski et al., J Acoust Soc Am 84: 1680-1694, 1988; Gescheider et al., Somatosens Mot Res 18: 191-201, 2001). The effect of changing stimulus duration was also essentially identical for both sites, demonstrating the same amount of temporal summation in the P channel. Although the effect of changing stimulus frequency and changing stimulus duration did not differ for the two sites, the effect of varying the size of the stimulus was significantly greater for the thenar eminence than for the fingertip. The attenuated amount of spatial summation on the fingertip was interpreted as an indication that the mechanism of spatial summation consists of the operations of both neural integration and probability summation.