Michael J. Matteucci

Antidote Use in the Critically Ill Poisoned Patient

The proper use of antidotes in the intensive care setting when combined with appropriate general supportive care may reduce the morbidity and mortality associated with severe poisonings. The more commonly used antidotes that may be encountered in the intensive care unit ( N -acetylcysteine, ethanol, fomepizole, physostigmine, naloxone, flumazenil, sodium bicarbonate, octreotide, pyridoxine, cyanide antidote kit, pralidoxime, atropine, digoxin immune Fab, glucagon, calcium gluconate and chloride, deferoxamine, phytonadione, botulism antitoxin, methylene blue, and Crotaline snake antivenom) are reviewed. Proper indications for their use and knowledge of the possible adverse effects accompanying antidotal therapy will allow the physician to appropriately manage the severely poisoned patient.

Pediatric sex group differences in location of snakebite injuries requiring antivenom therapy.

ObjectiveThe objective of this study is to examine the patterns of snakebite injury in pediatric patients that require antivenom therapy and to evaluate whether and when sex group differences exist.MethodsWe performed a nationwide, multicenter, retrospective evaluation of 24 regional poison centers from 2002 and through 2004 of data for antivenom therapy for Crotaline snakebites. Data points abstracted included the age of the victim, sex of the victim, and location of bite. We calculated contingency tables of the data with statistical significance by Fisher’s exact test.ResultsWe evaluated 204 records that involved pediatric patients; 3 of the patients had no recorded age. In 16 of the records, the bite location was not documented (2 children and 1 unknown age) or was listed as head/neck (1 child). These records were not included in the data analysis. There were bites in 136 males and 65 females. Males were more likely than females to suffer an injury to the upper extremity (56.6% vs. 26.2%; p < 0.01). Males were more likely to suffer injuries to the upper extremity in all age groups (p < 0.05) except for the group aged 10 through 12 years; in the group aged 10 through 12, we did not see significant differences between the sexes (p = 0.729). Males are more likely to suffer an upper extremity bite with increasing age (p = 0.029), while females showed no significant change in the location of bites (p = 0.223).ConclusionMale children were more likely than female children to suffer Crotaline snakebites that required antivenom therapy. In this population, significant differences between locations of snakebites were found. Males were more likely than females to be bitten in the upper extremities. This difference appears as early as 1 to 4 years of age.

Emergency Department Presentation of Superior Mesenteric Artery Syndrome: Two Cases in Marine Corps Recruits

BACKGROUND Superior mesenteric artery (SMA) syndrome is a relatively rare etiology of proximal intestinal obstruction. Obstruction results from marked narrowing of the angle between the SMA and aorta, causing compression of the third portion of the duodenum, most commonly as a result of precipitous weight loss. Intermittent non-specific symptoms at presentation often result in a delayed diagnosis, thus the importance of being aware of this condition. OBJECTIVE To familiarize emergency physicians with the presentation of SMA syndrome and discuss its diagnosis and management in the emergency department (ED). CASE REPORT We present two cases of SMA syndrome identified in Marine Corps recruits presenting to our ED. CONCLUSION Emergency physicians should include SMA syndrome in the differential diagnosis of abdominal pain and vomiting in individuals with predisposing factors.

Agreement Between Resident and Faculty Emergency Physicians in the Application of NEXUS Criteria for Suspected Cervical Spine Injuries

BACKGROUND The National Emergency X-Radiography Utilization Study (NEXUS) developed a decision rule for when cervical spine radiographs are required in the setting of trauma. To our knowledge, inter-rater reliability between resident and faculty emergency physicians has not been studied. OBJECTIVE This study seeks to compare the inter-rater agreement of postgraduate year (PGY) 2-4 emergency medicine (EM) residents vs. EM faculty physicians. METHODS A convenience sample of patients presenting to an urban, academic, Level II emergency department (ED) with complaints of cervical spine pain after trauma were enrolled. All subjects received separate examinations by an EM faculty physician and by a PGY 2-4 EM resident in a blinded fashion. Eighty subjects were enrolled in the study. RESULTS Agreement for each of the NEXUS components were: posterior midline tenderness (PMT) 85.0% and κ = 0.70, intoxication (TOX) 95.0% and κ = 0.72, altered mental status (AMS) 87.5% and κ = 0.22, focal neurologic deficit (FND) 92.5% and κ = 0.21, and presence of a distracting injury (DIS) 88.8% and κ = 0.13. Overall agreement for need for radiographs was 77.5% and κ = 0.53. Sixty of the subjects received radiography (28 computed tomography, 40 plain films, 8 both). One fracture (C1 lamina) was detected in this dataset. Two of the five NEXUS criteria (PMT, TOX) demonstrated substantial agreement, two (AMS, FND) fair agreement, and one (DIS) slight agreement. CONCLUSIONS Based on our findings, there was considerable difference in agreement between staff physicians and residents. This could be due to the level of experience of the provider or the subjectiveness of components the criteria.

Effect of Deferasirox on Iron Absorption in a Randomized, Placebo-Controlled, Crossover Study in a Human Model of Acute Supratherapeutic Iron Ingestion

STUDY OBJECTIVE In 2005, the Food and Drug Administration approved deferasirox as an oral iron chelating agent for chronic iron overload. To determine usefulness in management of acute iron ingestion, we study the effect of orally administered deferasirox in healthy human adults. METHODS A double-blinded, placebo-controlled, randomized, crossover study of 8 healthy human volunteers was conducted. Subjects ingested 5 mg/kg of elemental iron in the form of ferrous sulfate. One hour after iron ingestion, subjects were randomized to receive 20 mg/kg of deferasirox or placebo. Serial iron levels were then obtained. A 2-week washout was used between study arms. The paired t test was used to compare area under time-concentration curves from baseline to both 12- and 24-hour iron levels between groups. RESULTS Baseline serum iron levels were similar in the 2 groups. Deferasirox significantly reduced serum iron area under concentration-time curves compared with placebo during both 1 to 12 hours and 1 to 24 hours (12 hour=577 μmol-hour/L and 392 μmol-hour/L, 95% confidence interval for the difference 15.8 to 353.0 μmol-hour/L; 24 hour=808 μmol-hour/L and 598 μmol-hour/L, 95% confidence interval for difference 54.4 to 366.7 μmol-hour/L). CONCLUSION Orally administered deferasirox significantly reduced serum iron levels when administered 1 hour after iron ingestion during the 12- and 24-hour periods after acute ingestion of 5 mg/kg of elemental iron in healthy human volunteers. Further study is required to determine optimal dosing, but deferasirox may be an important addition to current therapy for acute iron poisoning.

Effect of Oral Calcium Disodium EDTA on Iron Absorption in a Human Model of Iron Overdose

Objective. Anecdotal case reports and animal models have suggested that the administration of CaNa2 EDTA (EDTA) may be effective in reducing the absorption of iron after an oral iron overdose. We designed this study to determine the effect of orally administrated EDTA with or without activated charcoal (AC) on iron absorption after a mild iron ingestion in healthy human volunteers. Methods. A randomized, crossover study was conducted in eight healthy human volunteers. All subjects ingested 5 mg/kg of elemental iron in the form of ferrous sulfate. One hour post ingestion, subjects were randomized to receive 35 mg/kg EDTA, EDTA plus 50 grams of AC, or water. Serial iron levels were obtained at baseline and every hour for the first 6 hours, then at 8, 12, and 24 hours. A 2-week washout was used between study arms. The Kruskal-Wallis test was used for the following comparisons between treatment groups: baseline serum iron levels, area under time-concentration curves (AUCs) from baseline to 12 hours and baseline to 24 hours, and peak iron levels. Results. Baseline serum iron levels did not differ among the three treatment groups (p = 0.844). AUCs were not different among groups (p = 0.746 for 12 hr, p = 0.925 for 24 hr). AUC medians (with 95% binomial confidence bounds) for control, EDTA, EDTA + AC groups, respectively, for 12 hr were: 2813 (2298, 3561), 2570 (1669, 3476), and 2654 (2125, 3600); and for 24 hr were: 4083 (3488,5314), 4139 (2666, 5547), and 4274 (3336, 5577). Peak serum iron levels did not differ among treatment groups (p = 0.481). Peak iron level medians in µg/dL (with 95% binomial confidence bounds) were for control: 329 (253, 382), for EDTA: 271 (184, 375), and for EDTA + AC: 285 (229, 352). Conclusion. Orally administered EDTA did not significantly reduce iron absorption when administered 1 hour post iron ingestion during the 12 or 24-hour period following the ingestion of 5 mg/kg of elemental iron in healthy human volunteers.

Measuring Arterial Oxygenation in a High Altitude Field Environment: Comparing Portable Pulse Oximetry With Blood Gas Analysis

OBJECTIVE High altitude environments present unique medical treatment challenges. Medical providers often use small portable pulse oximetry devices to help guide their clinical decision making. A significant body of high altitude research is based on the use of these devices to monitor hypoxia, yet there is a paucity of evidence that these devices are accurate in these environments. We studied whether these devices perform accurately and reliably under true mountain conditions. METHODS Healthy unacclimatized active-duty military volunteers participating in mountain warfare training at 2100 m (6900 feet) above sea level were evaluated with several different pulse oximetry devices while in a cold weather, high altitude field environment and then had arterial blood gases (ABG) drawn using an i-STAT for comparison. The pulse oximeter readings were compared with the gold standard ABG readings. RESULTS A total of 49 individuals completed the study. There was no statistically significant difference between any of the devices and the gold standard of ABG. The best performing device was the PalmSAT (PS) 8000SM finger probe with a mean difference of 2.17% and SD of 2.56 (95% CI, 1.42% to 2.92%). In decreasing order of performance were the PS 8000AA finger probe (mean ± SD, 2.54% ± 2.68%; 95% CI, 1.76% to 3.32%), the PS 8000Q ear probe (2.47% ± 4.36%; 95% CI, 1.21% to 3.75%), the Nonin Onyx 9500 (3.29% ± 3.12%; 95% CI, 2.39% to 4.20%), and finally the PS 8000R forehead reflectance sensor (5.15% ± 2.97%; 95% CI, 4.28% to 6.01%). CONCLUSIONS Based on the results of this study, results of the newer portable pulse oximeters appear to be closely correlated to that of the ABG measurements when tested in true mountain conditions.

Psychiatric implications of adolescent methamphetamine exposures.

Objectives Methamphetamine abuse has reached epidemic proportions during the last decade. Abuse among adolescents is linked to increased rates of depression and suicidal ideation. Sources suggest that there is an increase rate of suicide attempts in the methamphetamine-abusing adolescent patient population. Our study seeks to examine adolescent methamphetamine exposures reported to the California Poison Control System during the past decade of suicidal ideation and suicide attempts in comparison to rates reported by population-based surveys. Methods The records of the California Poison Control System were searched for methamphetamine exposures from 2000 to 2009. All charts of patients identified between the ages of 11 and 18 years were reviewed and abstracted. Results The records of 293 youth between the ages of 11 and 18 years were identified and assigned levels of severity according to parameters set by the National Poison Data System Medical Outcome Criteria of the American Association of Poison Control Centers. Charts were categorized as follows: 11 as major, 52 as moderate, and 75 as minor. The remainder of the charts were not evaluated because of no effect (n = 13) or unable to follow (n = 142). In this cohort, more females were reported than males (57%). The most common presenting symptom in this patient population was agitation (39%). The most common events were suicidal ideation (31%) and suicide attempts (21%). Conclusions In this data set, adolescent methamphetamine exposures were associated with increased rates of suicidal ideation and suicide attempts that are disproportionate to population-based surveys during the same period.

Respiratory Failure in a Child Due to Type 2 Postobstructive Pulmonary Edema.

Background Postobstructive pulmonary edema (POPE), sudden pulmonary edema after upper airway obstruction, is an important disease entity for pediatric emergency physicians to recognize and initiate prompt treatment. Type 1 POPE occurs after a sudden, severe upper airway obstruction, whereas type 2 POPE develops after acute relief of chronic airway obstructive. Case A 12-year-old boy, with a history of untreated sleep apnea, on postoperative day 2 from appendectomy, was brought to the emergency department in respiratory distress. The patient required urgent intubation, and copious pink frothy fluid was suctioned from the endotracheal tube. He was initially difficult to oxygenate, but with ventilator setting changes including a high positive end-expiratory pressure, the patient improved. He was discharged on hospital day 3 with nighttime BiPAP for home use. Conclusions Type 2 POPE should be considered in a patient presenting with respiratory distress and a history of sleep apnea. Optimal ventilator management includes use of PEEP in the 10 to 15 cm H2O range. The roles of diuretics and steroids are controversial. Most patients will do well after a brief period of ventilatory support (24–48 hours). With the rise of ambulatory surgery, pediatric emergency physicians must be attuned to both the surgical and anesthetic complications that occur in the early postoperative period.

Paget-Schroetter syndrome: diagnostic limitations of imaging upper extremity deep vein thrombosis ☆ ☆☆ ★ ★★

Paget-Schroetter syndrome is a rare but potentially debilitating condition affecting young, otherwise healthy individuals. This condition, also known as effort thrombosis, is an upper extremity deep vein thrombosis classically caused by anatomical abnormalities compressing the neurovascular structures of the thoracic outlet. The diagnosis is important to emergency medicine providers due to its secondary morbidity and mortality. Common complications affecting these active adults are pulmonary embolism and postthrombotic syndrome. Most patients report a precedent history of vigorous exercise or activity involving the upper extremities. We present a case of a 23-year-old man with redness and swelling of his dominant arm after weightlifting. Previous literature describes Paget-Schroetter syndrome from repetitive activities. The report highlights the limitations of imaging studies in proximal upper extremity deep vein thromboses. The initial selected imaging study, Doppler ultrasound, was negative in our case and was followed by a nondiagnostic computed tomographic venogram. Although ultrasound is the preferred diagnostic imaging modality, it is limited when thrombosis is present in the noncompressible region of the clavicle. Magnetic resonance venogram or computed tomographic venogram is recommended if index of suspicion is high and the ultrasound shows normal results, but these studies are highly dependent on technique, flow, and timing. The eventual diagnosis of axillosubclavian thrombosis was obtained only after specialty consultation and formal venography. This case discusses the limitations of each imaging modality and the importance of a comprehensive clinical approach to this rare diagnosis.