The Efficacy of Antivenin Latrodectus (Black Widow) Equine Immune F(ab')2 Versus Placebo in the Treatment of Latrodectism: A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial.

STUDY OBJECTIVE: The antivenom currently available for treatment of systemic black widow envenomation (latrodectism) is composed of equine whole immunoglobin. Although considered effective, it has been associated with anaphylaxis and 2 reported fatalities. We test the efficacy and safety of new equine antivenom composed of purified F(ab')2 antibody fragments. METHODS: A randomized, double-blind, placebo-controlled trial was conducted at 16 sites across the United States. Subjects aged 10 years or older with moderate to severe pain because of black widow spider envenomation received F(ab')2 antivenom or placebo. The primary outcome measure was treatment failure, which was defined as failure to achieve and maintain clinically significant reduction in pain for 48 hours posttreatment. Secondary measures of pain intensity differences and summed pain intensity difference were computed. Adverse events were recorded. RESULTS: Sixty patients were treated (29 antivenom and 31 placebo). The mean age was 39 years and 68% were male. There were 15 treatment failures in the antivenom group and 24 in the placebo group (P=.019). Differences in pain intensity difference between groups were lower at each postbaseline point, and the mean summed pain intensity difference was greater for the antivenom group (difference 2,133; 95% confidence interval 177 to 4,090). No deaths or serious drug-related adverse events were detected. CONCLUSION: The F(ab')2 antivenom met the predefined primary outcome of reduced treatment failures. Secondary outcomes of pain intensity difference and summed pain intensity difference also supported efficacy. The rate of symptom improvement in the placebo group was higher than expected, which may be related to enrollment criteria or placebo effect.

GatewayNet: a form of sequential rule mining.

BACKGROUND: The gateway hypothesis (and particularly the prediction of developmental stages in drug abuse) has been a subject of protracted debate since the 1970s. Extensive research has gone into this subject, but has yielded contradictory findings. We propose an algorithm for detecting both association and causation relationships given a discrete sequence of events, which we believe will be useful in addressing the validity of the gateway hypothesis. To assess the gateway hypothesis, we developed the GatewayNet algorithm, a refinement of sequential rule mining called initiation rule mining. After a brief mathematical definition, we describe how to perform initiation rule mining and how to infer causal relationships from its rules ("gateway rules"). We tested GatewayNet against data for which relationships were known. After constructing a transaction database using a first-order Markov chain, we mined it to produce a gateway network. We then discuss various incarnations of the gateway network. We then evaluated the performance of GatewayNet on urine drug screening data collected from the emergency department at LSU Health Sciences Center in Shreveport. A de-identified database of urine drug screenings ordered by the department between August 1998 and June 2011 was collected and then restricted to patients having at least one screening succeeding their first positive drug screening result. RESULTS: In the synthetic data, a chain of gateway rules was found in the network which demonstrated causation. We did not find any evidence of gateway rules in the empirical data, but we were able to isolate two documented transitions into benzodiazepine use. CONCLUSIONS: We conclude that GatewayNet may show promise not only for substance use data, but other data involving sequences of events. We also express future goals for GatewayNet, including optimizing it for speed.

Emergency room crowding: a marker of hospital health.

Emergency room (ER) crowding has become a widespread problem in hospitals across the United States. Two main reasons can be cited. First, emergency medicine is the only specialty in the "House of Medicine" that has a federal mandate to provide care to any patients requesting treatment. Second, primary care providers are in short supply, forcing sick people to seek medical care in ERs. Once seen as an "ER problem," crowding has become more appropriately recognized as a "hospital problem," related to factors beyond the doors of the ER. This realization has led many regulating agencies to launch corrective attempts, some of which have actually been effective. Now, the lack of ER crowding is considered a measure of the success of a hospital or system. This review considers the complex causative factors that contribute to ER crowding and explores corrective measures that may prove helpful in alleviating this paralyzing condition.

Dedicated emergency department ultrasound rotation improves residents' ultrasound knowledge and interpretation skills.

BACKGROUND: Graduates of Emergency Medicine (EM) residency training programs are expected to be proficient in ultrasound. However, best practices for teaching residents ultrasonography has yet to be determined. STUDY OBJECTIVES: To determine if a dedicated Emergency Department (ED) ultrasound rotation objectively improves residents' EM ultrasound knowledge, interpretation accuracy, and clinical decision-making based on ultrasound findings. METHODS: EM residents completing a required ED-based ultrasound rotation were prospectively studied. Before the start of the rotation, each resident completed a 20-question pre-test. At the end of the rotation, residents completed a 20-question post-test. Both tests covered physics, trauma (focused assessment with sonography for trauma), first-trimester pregnancy, aorta, biliary, echocardiography, and vascular sonography, using a multiple-choice format. In both tests, ultrasound images were included in 11 of the 20 questions. The questions were divided into three categories: knowledge-based (8 questions), interpretation (9 questions), and clinical decision-making (3 questions), for both tests. Scores on pre-tests and post-tests were compared using a Wilcoxon signed-rank test. RESULTS: During the 2-year study period, 21 residents completed the rotation. The median pre-test score was 16 (interquartile range [IQR] 14.5-17), compared to a median post-test score of 19 (IQR 18-20), p < 0.001. CONCLUSIONS: A dedicated ED ultrasound rotation improves residents' EM ultrasound knowledge and interpretation accuracy based on ultrasound findings, as measured by improvement on ultrasound test scores.

The impact of emergency department overcrowding on resident education.

BACKGROUND: Few studies have evaluated the effect of Emergency Department (ED) overcrowding on resident education. OBJECTIVES: To determine the impact of ED overcrowding on Emergency Medicine (EM) resident education. MATERIALS AND METHODS: A prospective cross-sectional study was performed from March to May 2009. Second- and third-year EM residents, blinded to the research objective, completed a questionnaire at the end of each shift. Residents were asked to evaluate the educational quality of each shift using a 10-point Likert scale. Number of patients seen and procedures completed were recorded. Responses were divided into ED overcrowding (group O) and non-ED overcrowding (group N) groups. ED overcrowding was defined as >2 h of ambulance diversion per shift. Questionnaire responses were compared using Mann-Whitney U tests. Number of patients and procedures were compared using unpaired T-tests. RESULTS: During the study period, 125 questionnaires were completed; 54 in group O and 71 in group N. For group O, the median educational value score was 8 (interquartile range [IQR] 7-10), compared to 8 (IQR 8-10) for group N (p = 0.24). Mean number of patients seen in group O was 12.3 (95% confidence interval [CI] 11.4-13.2), compared to 13.9 (95% CI 12.7-15) in group N (p = 0.034). In group O, mean number of procedures was 0.9 (95% CI 0.6-1.2), compared to 1.3 (95% CI 1-1.6) in group N (p = 0.047). CONCLUSIONS: During overcrowding, EM residents saw fewer patients and performed fewer procedures. However, there was no significant difference in resident perception of educational value during times of overcrowding vs. non-overcrowding.

Recognition and Work in the Platform Economy: a Normative Reconstruction.

The rise of the platform economy in the past two decades (and neoliberal capitalist expansion and crises more in general), have on the whole negatively affected working conditions, leading to growing concerns about the "human side" of organizations. To address these concerns, the purpose of this paper is to apply Axel Honneth's recognition theory and method of normative reconstruction to working conditions in the platform economy. The paper concludes that the ways in which platform organizations function constitutes a normative paradox, promising flexibility and autonomy while at the same time creating working conditions that undercut these promises. The paper ends with a critical discussion of Honneth's approach, possible supplementing ideas and further lines of future research.

Techniques for teaching electrocardiogram interpretation: self-directed learning is less effective than a workshop or lecture.

CONTEXT: Teaching 12-lead electrocardiogram (ECG) interpretation to students and residents is a challenge for medical educators. To date, few studies have compared the effectiveness of different techniques used for ECG teaching. OBJECTIVES: This study aimed to determine if common teaching techniques, such as those involving workshops, lectures and self-directed learning (SDL), increase medical students' ability to correctly interpret ECGs. It also aimed to compare the effectiveness of these formats. METHODS: This was a prospective randomised study conducted over a 28-month period. Year 4 medical students were randomised to receive teaching in ECG interpretation using one of three teaching formats: workshop, lecture or SDL. All three formats covered the same content. Students were administered three tests: a pre-test (before teaching); a post-test (immediately after teaching), and a retention test (1 week after teaching). Each tested the same content using 25 questions worth 1 point each. A mixed-model repeated-measures analysis of variance (anova) with least squares post hoc analysis was conducted to determine if differences in test scores between the formats were statistically significant. RESULTS: Of the 223 students for whom data were analysed, 79 were randomised to a workshop, 82 to a lecture-based format and 62 to SDL. All three teaching formats resulted in a statistically significant improvement in individual test scores (p < 0.001). Comparison of the lecture- and workshop-based formats demonstrated no difference in test scores (marginal mean [MM] for both formats = 12.4, 95% confidence interval [95% CI] 11.7-13.2]; p = 0.99). Test scores of students using SDL (MM = 10.7, 95% CI 9.8-11.5) were lower than those of students in the workshop (p = 0.003) and lecture (p = 0.002) groups. CONCLUSIONS: Compared with those taught using workshop- and lecture-based formats, medical students learning ECG interpretation by SDL had lower test scores.

Resuscitation with balanced electrolyte solution prevents hyperchloremic metabolic acidosis in patients with diabetic ketoacidosis.

OBJECTIVE: The objective of the study was to determine if balanced electrolyte solution (BES) prevents hyperchloremic metabolic acidosis in patients with diabetic ketoacidosis (DKA). METHODS: This is a prospective, randomized, double-blind study. A convenience sample of DKA patients aged 18 to 65 years with serum bicarbonate less than or equal to 15 and anion gap greater than or equal to 16 was enrolled at "Louisiana State University Health Sciences Center-Shreveport" an capitalize Emergency Department over a 24-month period (2006-2008). Patients were randomized to standardized resuscitation with normal saline (NS) or BES (Plasma-Lyte A pH 7.4; Baxter International, Deerfield, IL). Every 2 hours, serum chloride and bicarbonate were measured until the patient's anion gap decreased to 12. An intention-to-treat analysis was performed on patients who met inclusion criteria and received at least 4 hours of study fluid. Chloride and bicarbonate measurements from the BES and NS groups were compared using unpaired and paired Student t tests. RESULTS: Of 52 patients enrolled, 45 (22 in BES group and 23 in NS group) met inclusion criteria and received 4 hours of fluid. The mean postresuscitation chloride was 111 mmol/L (95% confidence interval [CI] = 110-112) in the NS group and 105 mmol/L (95% CI = 103-108) in the BES group (P ≤ .001). The mean postresuscitation bicarbonate was 17 mmol/L (95% CI = 15-18) in the NS group and 20 mmol/L (95% CI = 18-21) in the BES group (P = .020). CONCLUSIONS: Resuscitation of DKA patients with BES results in lower serum chloride and higher bicarbonate levels than patients receiving NS, consistent with prevention of hyperchloremic metabolic acidosis.

Short- vs long-axis approach to ultrasound-guided peripheral intravenous access: a prospective randomized study.

OBJECTIVE: The objective of the study was to determine if the short-axis approach and long-axis approach to ultrasound-guided peripheral intravenous access (USGPIV) differ in success rate, catheter insertion time, and number of needle sticks. METHODS: A convenience sample of emergency department patients aged 18 to 65 years with difficult IV access (2 or more failed landmark attempts) was prospectively randomized to short-axis or long-axis USGPIV. Time from skin puncture to catheter insertion (insertion time) and number of needle sticks were recorded. Number of needle sticks and insertion time were compared using Mann-Whitney U tests. RESULTS: Forty subjects were enrolled; 20 were randomized to the short-axis and 20 to the long-axis approach. Success rate was 95% (19/20; 95% confidence interval, 85%-100%) in the short-axis group compared with 85% (17/20; 95% confidence interval, 69%-100%) in the long-axis group. All 3 subjects with failed IV placement in the long-axis group had successful rescue USGPIV placement in short axis. Median insertion time was 34 seconds (interquartile range, 35 seconds) for the short-axis group compared with 91 seconds (interquartile range, 59 seconds) for the long-axis group (P = .02). Mean number of needle sticks was 1.5 (±SD 0.7) in the short-axis group compared with 1.4 (±SD 0.7) in the long-axis group (P = .82). CONCLUSIONS: Short-axis USGPIV technique required less insertion time than the long-axis technique. Success rate was higher in the short-axis group, but this difference was not statistically significant. However, all of the failed IVs in the long axis were rescued successfully in short axis.

Clinical sobriety assessment by emergency physicians in blunt trauma patients with acute alcohol exposure.

BACKGROUND: Alcohol use increases injury risk and severity. However, few studies have evaluated the ability of emergency physicians (EPs) to accurately determine sobriety. OBJECTIVES: To determine the predictive value of clinical sobriety assessment by EPs in blunt trauma patients with acute alcohol use. MATERIALS AND METHODS: Blunt trauma patients, aged 18-65 years with suspected acute alcohol use, were prospectively enrolled in the study. EPs assessed study subjects before sample collection for blood alcohol level (BAL) and urine drug screen measurement. Alcohol exposure was considered significant if BAL was ≥ 80 mg/dL. Sobriety (non-significant alcohol exposure) was defined as a BAL < 80 mg/dL. EP sobriety assessment was compared to measured BAL and predictive values were calculated. Agreement on significance of alcohol exposure occurred if EP-estimated BAL > 80 mg/dL agreed with measured BAL > 80 mg/dL, or estimated BAL < 80 mg/dL agreed with measured BAL < 80 mg/dL. Chi-squared analysis was used to compare the proportion of correct physician assessments among patients with sobriety and those with significant alcohol exposure. RESULTS: Of 158 enrolled subjects, 153 completed clinical assessment. EP assessment had a predictive value of 83% (95% confidence interval [CI] 77-90%) for significant alcohol exposure and 69% (95% CI 60-78%) for sobriety. Agreement on the significance of alcohol exposure was 82% (125/153; 95% CI 76-88%). EPs identified 32% (11/34; 95% CI 17-48%) of sober patients, but identified 96% (114/119; 95% CI 92-99%) of patients with significant alcohol exposure. EP assessment was significantly less accurate in identifying sober patients (p < 0.01). CONCLUSIONS: Emergency physicians identified significant recent alcohol exposure in blunt trauma patients 96% of the time. However, clinical assessment by EPs in blunt trauma patients with recent alcohol use had only moderate predictive value for significant alcohol exposure. Sober patients were frequently misidentified as having significant alcohol exposure.

Comparison of F(ab')2 versus Fab antivenom for pit viper envenomation: a prospective, blinded, multicenter, randomized clinical trial.

BACKGROUND: Crotalidae Polyvalent Immune Fab (Ovine) has been the only antivenom commercially available in the US since 2007 for treatment of Crotalinae envenomation. Late coagulopathy can occur or recur after clearance of Fab antivenom, often after hospital discharge, lasting in some cases more than 2 weeks. There have been serious, even fatal, bleeding complications associated with recurrence phenomena. Frequent follow-up is required, and additional intervention or hospitalization is often necessary. F(ab')2 immunoglobulin derivatives have longer plasma half life than do Fab. We hypothesized that F(ab')2 antivenom would be superior to Fab in the prevention of late coagulopathy following treatment of patients with Crotalinae envenomation. METHODS: We conducted a prospective, double-blind, randomized clinical trial, comparing late coagulopathy in snakebitten patients treated with F(ab')2 with maintenance doses [F(ab')2/F(ab')2], or F(ab')2 with placebo maintenance doses [F(ab')2/placebo], versus Fab with maintenance doses [Fab/Fab]. The primary efficacy endpoint was coagulopathy (platelet count < 150 K/mm(3), fibrinogen level < 150 mg/dL) between end of maintenance dosing and day 8. RESULTS: 121 patients were randomized at 18 clinical sites and received at least one dose of study drug. 114 completed the study. Of these, 11/37 (29.7%) in the Fab/Fab cohort experienced late coagulopathy versus 4/39 (10.3%, p < 0.05) in the F(ab')2/F(ab')2 cohort and 2/38 (5.3%, p < 0.05) in the F(ab')2/placebo cohort. The lowest heterologous protein exposure was with F(ab')2/placebo. No serious adverse events were related to study drug. In each study arm, one patient experienced an acute serum reaction and one experienced serum sickness. CONCLUSIONS: In this study, management of coagulopathic Crotalinae envenomation with longer-half-life F(ab')2 antivenom, with or without maintenance dosing, reduced the risk of subacute coagulopathy and bleeding following treatment of envenomation.

Near-infrared spectroscopy: a tool to monitor cerebral hemodynamic and metabolic changes after cardiac arrest in rats.

INTRODUCTION: Cardiac arrest (CA) is associated with poor neurological outcome and is associated with a poor understanding of the cerebral hemodynamic and metabolic changes. The objective of this study was to determine the applicability of near-infrared spectroscopy (NIRS), to observe the changes in cerebral total hemoglobin (T-Hb) reflecting cerebral blood volume, oxygenation state of Hb, oxidized cytochrome oxidase (Cyto-C), and brain water content following CA. METHODS: Fourteen rats were subjected to normothermic (37.5 degrees C) or hypothermic (34 degrees C) CA induced by 8 min of asphyxiation. Animals were resuscitated with ventilation, cardiopulmonary resuscitation (CPR), and epinephrine (adrenaline). Hypothermia was induced before CA. NIRS was applied to the animal head to measure T-Hb with a wavelength of 808 nm (n = 10) and oxygenated/deoxygenated Hb, Cyto-C, and brain water content with wavelengths of 620-1120 nm (n = 4). RESULTS: There were no technical difficulties in applying NIRS to the animal, and the signals were strong and consistent. Normothermic CA caused post-resuscitation hyperemia followed by hypoperfusion determined by the level of T-Hb. Hypothermic CA blunted post-resuscitation hyperemia and resulted in more prominent post-resuscitation hypoperfusion. Both, normothermic and hypothermic CA resulted in a sharp decrease in oxygenated Hb and Cyto-C, and the level of oxygenated Hb was higher in hypothermic CA after resuscitation. There was a rapid increase in brain water signals following CA. Hypothermic CA attenuated increased water signals in normothermic CA following resuscitation. CONCLUSION: NIRS can be applied to monitor cerebral blood volume, oxygenation state of Hb, Cyto-C, and water content following CA in rats.

Initial experience with Crotalidae polyvalent immune Fab (ovine) antivenom in the treatment of copperhead snakebite.

STUDY OBJECTIVE: Crotalidae polyvalent immune Fab (ovine) (CroFab; FabAV) effectively treats patients bitten by rattlesnakes. The copperhead snake (Agkistrodon contortrix) caused 37% of venomous snakebites reported to US poison centers in 2001 and is the major envenomating reptile in the southeastern United States. FabAV has not been tested in human beings envenomated by copperhead snakes. METHODS: In this preliminary study, we performed a retrospective chart review of all copperhead snake envenomations reported to the Carolinas Poison Center that were treated with FabAV. Progression of limb swelling, coagulopathy, and hemodynamic status before and after FabAV administration, adverse effects of FabAV therapy, and recurrence phenomena were recorded. RESULTS: Of approximately 400 copperhead envenomation cases reported to the poison center during the study period, 32 received FabAV and were included. Most patients had moderate envenomation. The median time to FabAV administration was 4.0 hours. The median time to achieve initial control was 1.0 hour, with a median dose of 4 vials of FabAV. A rapid initial response, defined as cessation of the progression of local tissue injury within 4 hours of FabAV administration, occurred in 28 cases (88%; 95% confidence interval [CI] 76% to 99%). Four cases (13%; 95% CI 1% to 24%) were considered treatment failures. Recurrent swelling occurred in 6 cases (19%; 95% CI 5% to 32%). The incidence of recurrent swelling was not reduced by administration of repeated doses of antivenom on a planned schedule. One patient developed late-onset coagulopathy. One minor allergic reaction was observed. CONCLUSION: In this select group of patients bitten by copperhead snakes, local tissue effects of envenomation halted promptly after FabAV treatment in most cases. Treatment failures occurred, and recurrence of swelling and defibrination syndrome was sometimes problematic. Time to return to work and long-term limb function were not assessed. A controlled trial with long-term follow-up is needed to define the role of FabAV treatment for copperhead envenomation.

Cerebral cortical aquaporin-4 expression in brain edema following cardiac arrest in rats.

OBJECTIVES: Brain edema occurs following clinical as well as experimental cardiac arrest (CA) and predicts a poor neurologic outcome. The objective of this study was to determine the expression of cerebral cortex aquaporin (AQP)-4, a member of a family of membrane water-channel proteins, in brain edema formation following normothermic or hypothermic CA. METHODS: Twenty-four rats were subjected to time-matched normothermic (N-Sham, 37.5 degrees C +/- 0.5 degrees C, n = 6) or hypothermic (H-Sham, 34 degrees C +/- 0.5 degrees C, n = 6) sham experiments and normothermic (N-CA, n = 6) or hypothermic (H-CA, n = 6) CA induced by asphyxiation for 8 minutes. Hypothermia was induced before CA. The animals were resuscitated with cardiopulmonary resuscitation, ventilation, and epinephrine administration. Brain edema was determined by brain wet-to-dry weight ratio at one hour of resuscitation. AQP4 immunoactivity in the cerebral cortex was determined using immunohistochemical staining and was semiquantified as an intensity of staining with an automated cell imaging system. RESULTS: Mild hypothermia in the sham experiments did not alter cerebral cortex AQP4 immunoactivity (mean +/- SD) (55.0 +/- 3.7 in H-Sham vs. 53.3 +/- 1.7 in N-Sham, p > 0.05). N-CA resulted in a significant increase in AQP4 immunoactivity (61.8 +/- 4.5) compared with N-Sham (p = 0.01) and H-Sham (p = 0.03). H-CA attenuated AQP4 compared with N-CA (53.4 +/- 1.3, p = 0.01). Brain wet-to-dry weight ratios were 4.41 +/- 0.07 in N-Sham, 4.40 +/- 0.08 in H-Sham (p > 0.05 vs. N-Sham), 4.55 +/- 0.04 in N-CA (p = 0.004 vs. N-Sham; p = 0.005 vs. H-Sham), and 4.43 +/- 0.09 in H-CA (p = 0.02 vs. N-CA; p > 0.05 vs. N-Sham and H-Sham). CONCLUSIONS: Cerebral cortical AQP4 expression is up-regulated after normothermic CA, which is attenuated by hypothermia induced before CA.

Mild hypothermia induced before cardiac arrest reduces brain edema formation in rats.

OBJECTIVES: The mechanisms by which hypothermia improves cardiac arrest (CA)-induced brain damage are unclear. The authors hypothesized that mild hypothermia induced before CA attenuates brain edema formation by preventing neutrophil-mediated dysfunction of the endothelial cell junction proteins. METHODS: Eighteen rats were randomized to normal control surgery (group 1, n = 6), normothermic (37.5 degrees C) CA (group 2, n = 6), or hypothermic (34 degrees C) CA (group 3, n = 6). Hypothermia was induced with external cooling before CA in group 3. Cardiac arrest was induced by 8 minutes of asphyxiation. Brain edema was determined by wet-to-dry weight ratio and cerebral spinal fluid pressure (CSFP). Brain neutrophil content was determined by myeloperoxidase (MPO) activity, and occludin degradation was assessed by western blotting. RESULTS: Normothermic CA significantly increased brain wet-to-dry weight ratio from 4.52 +/- 0.04 in group 1 to 4.80 +/- 0.04 in group 2 (p = 0.0003) and CSFP from 3.6 +/- 0.9 in group 1 to 8.9 +/- 0.9 mm Hg in group 2 (p = 0.004). Mild hypothermia before CA in group 3 significantly reduced brain wet-to-dry weight ratio (4.68 +/- 0.03, p = 0.008 vs. group 2) and CSFP (3.8 +/- 0.5 mm Hg, p = 0.004 vs. group 2). Cardiac arrest increased brain MPO from 0.07 +/- 0.025 in group 1 to 0.16 +/- 0.02 units/gram brain weight in group 2 (p = 0.006) that was not decreased by hypothermia before CA (0.12 +/- 0.02 in group 3 (p = 0.07 vs. group 2). There was no occludin proteolysis in any group. CONCLUSIONS: Mild hypothermia before CA decreases CA-induced brain edema. The hypothermia-elicited reduction in brain edema does not appear to be neutrophil-dependent and the early brain edema formation may not involve the proteolysis of occludin.

Can we make the basilic vein larger? maneuvers to facilitate ultrasound guided peripheral intravenous access: a prospective cross-sectional study.

BACKGROUND: Studies have shown that vein size is an important predictor of successful ultrasound-guided vascular access. The objective of this study is to evaluate maneuvers designed to increase basilic vein size, which could be used to facilitate ultrasound-guided peripheral intravenous access (USGPIV) in the Emergency Department (ED) setting. METHODS: This was a prospective non-randomized trial. Healthy volunteers aged 18-65 were enrolled. Basilic veins were identified and the cross-sectional area measured sonographically. Following baseline measurement, the following maneuvers were performed: application of a tourniquet, inflation of a blood pressure (BP) cuff, application of a tourniquet with the arm lowered, and BP cuff inflation with the arm lowered. Following each maneuver there was 30 s of recovery time, and a baseline measurement was repeated to ensure that the vein had returned to baseline. Change in basilic vein size was modeled using mixed model analysis with a Tukey correction for multiple comparisons to determine if significant differences existed between different maneuvers. RESULTS: Over the 5-month study period, 96 basilic veins were assessed from 52 volunteers. All of the maneuvers resulted in a statistically significant increase in basilic vein size from baseline (p < 0.001). BP cuff inflation had the greatest increase in vein size from baseline 17%, 0.87 mm 95% CI (0.70-1.04). BP cuff inflation statistically significantly increased vein size compared to tourniquet placement by 3%, 0.16 mm 95% CI (0.02-0.30). CONCLUSIONS: The largest increase in basilic vein size was due to blood pressure cuff inflation. BP cuff inflation resulted in a statistically significant increase in vein size compared to tourniquet application, but this difference may not be clinically significant.

Intestinal angioedema misdiagnosed as recurrent episodes of gastroenteritis.

Emergency physicians (EP) frequently encounter angioedema involving the lips and tongue. However, angioedema from Angiotensin Converting Enzyme inhibitors or hereditary angioedema (HAE) can present with gastrointestinal symptoms due to bowel wall involvement. EPs should begin to consider this clinical entity as a potential cause for abdominal pain and associated gastrointestinal symptoms given the common use of medications that can precipitate angioedema. We report a case of a 34-year-old woman who presented with abdominal cramping, vomiting and diarrhea due to an acute exacerbation of HAE.

Protective effects of low respiratory frequency in experimental ventilator-associated lung injury.

OBJECTIVE: To determine whether ventilator-associated lung hyperinflation injury can be attenuated by a reduction in respiratory frequency. DESIGN: Prospective comparative laboratory investigation. SETTING: University medical center research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Eight groups of isolated, perfused rat lungs were exposed to cyclic ventilation at different respiratory frequencies and tidal volumes. Each group of six to eight lung preparations was assigned to one of four respiratory frequencies (10, 20, 40, or 80 breaths/min) and one of two tidal volumes (5 or 20 mL.kg). Measurement of capillary filtration coefficient (Kf,c), a sensitive index of lung microvascular permeability and injury, was made at baseline and at 30, 60, and 90 mins of the experimental conditions. MEASUREMENTS AND MAIN RESULTS: Lungs exposed to 5 mL.kg tidal volume had no elevation in Kf,c at any time point regardless of respiratory frequency. Lungs exposed to 20 mL. kg tidal volume and a respiratory frequency of 80 had significant elevations in Kf,c at all times after baseline compared with lungs exposed to respiratory frequencies of 10, 20, or 40 (0.14 +/- 0.03, 0.16 +/- 0.02, 0.31 +/- 0.05 vs. 0.76 +/- 0.16). Furthermore, the Kf,c at 90 mins was significantly higher than permeability at baseline in this group (1.53 +/- 0.45 vs. 0.12 +/- 0.02 mL.min.cm H2O.100 g of lung tissue). CONCLUSIONS: Reduction in respiratory frequency to values much lower than normal ameliorated experimental ventilator-induced hyperinflation lung injury as determined by pulmonary capillary filtration coefficient.

Pressure-controlled ventilation attenuates lung microvascular injury in a rat model of activated charcoal aspiration.

BACKGROUND: Previous animal data suggest that aspiration of activated charcoal is associated with pulmonary microvascular injury that may be related to excessive ventilator-induced airway pressures. The purpose of this study was to test the hypothesis that ventilator-induced airway trauma contributes to the lung vascular injury observed following activated charcoal aspiration. METHODS: Capillary filtration coefficient (Kf,c), a sensitive measure of lung microvascular permeability, was determined isogravimetrically prior to and after intratracheal instillation of 0.4 ml/kg (12% weight/vol. solution, pH 7.4) activated charcoal oran equal volume of sterile water in isolated, perfused rat lungs in which ventilation was either pressure-controlled at 10cm H2O or volume-controlled at 5 ml/kg. RESULTS: There was significant lung injury in both activated charcoal groups regardless of ventilation method compared to control lungs or lungs administered sterile water (p < 0.05 ANOVA). However, injury to pressure-controlled ventilated lungs was significantly less than lungs ventilated with traditional, volume-controlled ventilation. CONCLUSION: The results of this investigation demonstrate that pressure-controlled ventilation reduces the lung microvascular injury observed following aspiration of activated charcoal as compared to traditional volume-controlled ventilation methods.