Papers by Shaun Carstairs
Journal of Military and Veterans' Health, Jul 1, 2017
Academic Emergency Medicine, May 1, 2013
Background: Patients sustaining rattlesnake envenomation often develop thrombocytopenia, the etio... more Background: Patients sustaining rattlesnake envenomation often develop thrombocytopenia, the etiology of which is not clear. Laboratory studies have demonstrated that venom from several species, including the Mojave rattlesnake (Crotalus scutulatus scutulatus), can inhibit platelet aggregation. In humans, administration of crotaline Fab antivenom has been shown to result in transient improvement of platelet levels; however, it is not known whether platelet aggregation also improves after antivenom administration. Objectives: The objective was to determine the effect of C. scutulatus venom on platelet aggregation in vitro in the presence and absence of crotaline Fab antivenom. Methods: Blood was obtained from four healthy male adult volunteers not currently using aspirin, nonsteroidal anti-inflammatory drugs, or other platelet-inhibiting agents. C. scutulatus venom from a single snake with known type B (hemorrhagic) activity was obtained from the National Natural Toxins Research Center. Measurement of platelet aggregation by an aggregometer was performed using five standard concentrations of epinephrine (a known platelet aggregator) on platelet-rich plasma over time, and a mean area under the curve (AUC) was calculated. Five different sample groups were measured: 1) blood alone, 2) blood + C. scutulatus venom (0.3 mg/mL), 3) blood + crotaline Fab antivenom (100 mg/ mL), 4) blood + venom + antivenom (100 mg/mL), and 5) blood + venom + antivenom (4 mg/mL). Standard errors of the mean (SEM) were calculated for each group, and paired t-tests were used to measure differences between groups.
Pediatrics, Dec 1, 2010
OBJECTIVE: We sought to identify characteristics of children with reported ingestion of Lantana c... more OBJECTIVE: We sought to identify characteristics of children with reported ingestion of Lantana camara. METHODS: We reviewed the California Poison Control System database for all reported pediatric ingestions of L camara for the years 1997–2008. Data collected included age, gender, clinical effects, duration of effects, medical interventions, and outcomes. RESULTS: There were a total of 641 patients; patient ages ranged from 1 to 16 years, with a mean of 2.5 years. Reported effects included vomiting (n = 30), abdominal pain (n = 8), agitation (n = 6), diarrhea (n = 6), throat/mouth irritation (n = 5), tachycardia (n = 4), drowsiness (n = 3), nausea (n = 2), and mydriasis (n = 1). There was no difference in frequency of symptoms between patients who ingested ripe (15.5% [95% confidence interval: 9.1%–21.8%]) versus unripe (6.0% [95% confidence interval: 0.9%–11.1%]) berries or between patients who ingested berries (10.5% [95% confidence interval: 7.3%–13.8%]) versus other plant parts (7.1% [95% confidence interval: 4.0%–10.3%]). Fifty-one patients (8%) were treated in a health care facility and 2 (0.3%) were admitted. No significant effects and no deaths were recorded. CONCLUSIONS: Ingestion of L camara (including unripe berries) was not associated with significant toxicity; patients who ingested unripe berries did not exhibit more-frequent or more-severe symptoms than did patients who ingested ripe berries or other plant parts. Most patients displayed no or minimal symptoms. Children with asymptomatic ingestions and those with mild symptoms can be treated at home.
Clinical Toxicology, Mar 1, 2011
Academic Emergency Medicine, May 1, 2006
Objectives: Computed tomography (CT) followed by lumbar puncture (LP) is currently the criterion ... more Objectives: Computed tomography (CT) followed by lumbar puncture (LP) is currently the criterion standard for diagnosing subarachnoid hemorrhage (SAH) in the emergency department (ED); however, this is based on studies involving a limited number of patients. The authors sought to assess the ability of CT angiography (CTA), a new diagnostic modality, in conjunction with CT/LP to detect SAH. Methods: Consecutive patients presenting to the ED with symptoms concerning for SAH were approached. All patients had an intravenous catheter placed and underwent a noncontrast head CT followed by CTA. Patients whose CT did not reveal evidence of SAH or other pathology underwent LP in the ED. CTAs were read within 24 hours by a neuroradiologist blinded to the patient's history. Results: A total of 131 patients were approached, 116 were enrolled, and 106 completed the study. In six of 116 patients (5.1%), aneurysm was found on CTA with normal CT and positive findings on LP; three had a positive CTA with normal CT and LP findings (one of which had a negative cerebral angiogram), and there was one false-positive CTA. Follow-up of all 131 patients showed no previously undiagnosed intracranial pathology. In this patient population, 4.3% (5/116) were ultimately found to have an SAH and/or aneurysm. Conclusions: In this pilot study, CTA was found to be useful in the detection of cerebral aneurysms and may be useful in the diagnosis of aneurysmal SAH. A larger multicenter study would be useful to confirm these results.
Academic Emergency Medicine, Feb 1, 2006
Objectives: North American coral snake antivenin (CSAV; Wyeth Antivenin [Micrurus fulvius], equin... more Objectives: North American coral snake antivenin (CSAV; Wyeth Antivenin [Micrurus fulvius], equine origin) is approved for the treatment of coral snake envenomations in the United States. The coral snake is the only elapid that is native to North America, but envenomations from non-native elapids are occurring more commonly in this country. This study was designed to evaluate the efficacy of CSAV in the neutralization of two exotic elapid envenomations: Naja naja (Indian cobra) and Dendroaspis polylepsis (black mamba). Methods: A randomized, blinded, placebo-controlled murine model of intraperitoneal venom injection was employed. Venom potency was determined in preliminary dosing studies. Study animals then were divided into five groups: 1) N. naja venom + CSAV, 2) N. naja venom + 0.9% normal saline (NS), 3) D. polylepsis venom + CSAV, 4) D. polylepsis venom + NS, and 5) CSAV + NS. The venom dose was chosen to be twice the estimated LD 50. The amount of CSAV injected was ten times the amount necessary for neutralization of a 2 Â LD 50 dose of M. f. fulvius venom in a murine model. Statistical analysis included Fisher's exact and log-rank testing to compare survival rates and times. Results: Preliminary studies estimated the venom LD 50 to be 2.58 mg/kg and 0.45 mg/kg, respectively, for the N. naja and D. polylepsis. A significant difference was shown in comparison of survival times between CSAV-venom groups and normal saline-venom groups despite all animals in both treatment and control arms dying. Animals receiving CSAV and N. naja venom survived (mean AE SD) 24.4 AE 3.0 minutes, versus 17.8 AE 1.3 minutes in the control group (p < 0.001), whereas those receiving CSAV and D. polylepsis venom survived 203.8 AE 37.0 minutes versus 130.0 AE 42.6 minutes in the control group (p < 0.001). All animals in the CSAV + NS group survived to the conclusion of the study. Conclusions: When premixed with venom, CSAV increased survival time in a murine model of intraperitoneal N. naja and D. polylepsis venom injection. The clinical implications of this are unclear, given unchanged mortality rates.
Journal of Medical Toxicology, Oct 3, 2016
The Journal of emergency medicine, May 1, 2004
Clinical Toxicology, Jul 31, 2013
American Journal of Emergency Medicine, Sep 1, 2010
The Journal of emergency medicine, Jun 1, 2011
Clinical Toxicology, May 3, 2013
Journal of Military and Veterans' Health, 2017
The state of California is home to greater than 168,000 active-duty military personnel, more than... more The state of California is home to greater than 168,000 active-duty military personnel, more than any other state in the United States of America. Additionally, there are more than 2 million military veterans in California, many of whom utilise Veterans Administration hospitals for their healthcare. Little, if any, has been published in the medical literature regarding poisoning in these potentially unique patient populations. It is not known whether the active-duty population differs from the veteran population in terms of frequency and types of toxicologic exposures. We sought to compare poisoned patients at military and Veterans Administration hospitals that were reported to the California Poison Control System in order to determine whether any differences exist between the two populations with respect to frequency or types of exposures, as well as age and gender distributions.
Clinical Toxicology, 2019
The Journal of Pediatric Pharmacology and Therapeutics, 2019
OBJECTIVES An increasing number of pediatric patients with psychiatric chief complaints present t... more OBJECTIVES An increasing number of pediatric patients with psychiatric chief complaints present to emergency departments (EDs) nationwide. Many of these patients require treatment with antipsychotic medications to treat agitation. We sought to examine the use of antipsychotic medications in pediatric patients presenting to a tertiary care pediatric ED. METHODS We performed a retrospective electronic medical record review of patients presenting to a tertiary care pediatric hospital from January 2009 through February 2016 with a psychiatric chief complaint who received an antipsychotic medication in the ED. RESULTS A total of 229 patients were identified, 54.1% of whom were male. Mean age was 14.4 ± 2.6 years. Commonly administered medications included olanzapine (51.1%), aripiprazole (26.6%), haloperidol (24.0%), and risperidone (11.8%). Eighty-seven patients (38.0%) were given at least 1 intravenous or intramuscular dose of antipsychotic medication. A total of 113 patients (49.3%) r...
Journal of medical toxicology : official journal of the American College of Medical Toxicology, Jan 17, 2018
First responders and health care providers must prepare to provide care for patients poisoned by ... more First responders and health care providers must prepare to provide care for patients poisoned by acetylcholinesterase (AchE) inhibitor chemical warfare agents or pesticides. However, pre-deployed medical countermeasures (MCMs) may not be sufficient due to production and delivery interruption, rapid depletion of contents during a response, expiration of MCM components, or lack of local availability of approved MCMs. To augment supplies of community-based and forward-deployed nerve agent countermeasures, the American College of Medical Toxicology (ACMT) supports several strategies: (1) The use of expired atropine, diazepam, and pralidoxime auto-injectors and vials if non-expired drugs are unavailable; and (2) Investigation, development, and identification of alternative countermeasures-commonly stocked drugs that are not approved for nerve agent poisoning but are in the same therapeutic class as approved drugs.
Clinical toxicology (Philadelphia, Pa.), Jan 23, 2017
Cyanoacrylate (Super Glue(®)) exposures are commonly reported to poison control centers, but litt... more Cyanoacrylate (Super Glue(®)) exposures are commonly reported to poison control centers, but little has been published in the medical literature regarding these exposures. We sought to characterize cyanoacrylate exposures reported to a poison control system. We performed a retrospective review of a poison system's database for all cases of single-substance human exposure to cyanoacrylate-containing products from 2005 to 2015. Data collected included age, gender, route of exposure, clinical effects, treatments recommended and medical outcome. There were a total of 893 patients, 505 (56.6%) of which were female. Patient ages ranged from 6 months to 88 years with a median of 11 years. The vast majority of exposures (n = 871, 97.5%) were unintentional, but a small number of exposures (n = 22, 2.5%) were due to intentional misuse (such as trying to stop a bleeding cut) or malicious intent (such as purposefully gluing a person's eyes shut as a prank). Routes of exposure included: ...
Annals of Emergency Medicine, 2016
Study Objectives: Increasing number of pediatric patients with psychiatric chief complaints are p... more Study Objectives: Increasing number of pediatric patients with psychiatric chief complaints are presenting to hospital emergency departments (EDs) nationwide. Some of these patients arrive to the ED acutely agitated or become agitated during their stay, and many of them require treatment with antipsychotic medications to treat their agitation. We reviewed the use of antipsychotic medications in pediatric patients presenting to a single tertiarycare pediatric emergency department. Methods: We performed a retrospective review of the electronic medical record from Jan 2009-Feb 2016 to identify all patients presenting to the ED with a psychiatric chief complaint who were administered at least one antipsychotic medication during their ED stay. Data collected included age, sex, whether the patient was already on antipsychotic medications prior to their ED visit, vital signs, chief complaints, medications and dosages administered, route of administration, length of ED stay, and patient disposition. Results: 229 patients were identified, 54.1% of whom were male. Mean patient age was 14.6AE2.3 years (median 15 years; range, 4-19 years). 85.2% were already on antipsychotic medications. 18.3% were tachycardic and 5.7% were hypertensive on presentation. Presenting complaints included suicidal ideation (47.6%), aggression (27.5%), homicidal ideation (10.5%), agitation (7%), psychosis (2.6%), and hallucinations (2.2%). Medications administered included olanzapine (51.1%), aripiprazole (26.6%), haloperidol (24.0%), risperidone (11.4%), quetiapine (10.0%), lurasidone (3.9%), and ziprasidone (2.2%). Eighty patients (34.9%) were given at least 1 intravenous or intramuscular dose of antipsychotic. A total of 173 patients (75.5%) were administered 1 antipsychotic medication, 43 (18.8%) were administered 2 antipsychotics, and 13 (5.7%) were administered 3 antipsychotics during their ED stay. A total of 191 patients (83.4%) were admitted to an inpatient mental health facility; 38 (16.6%) were discharged. Median length of stay was 683 min (IQR 410-1239) for patients given 1 antipsychotic, 888.5 min (IQR 549-1496) for patients given 2 antipsychotics, and 1239 min (IQR 874-1652) for patients given 3 antipsychotics (Kruksal-Wallis c2¼7.48; p¼0.024). Length of stay was shorter in patients given only oral medications (617 min, IQR 418-1194) compared to those given at least 1 parenteral dose of antipsychotic (979 min, IQR 458-1671) (z¼-2.47; p¼0.014). Conclusion: In this retrospective series, the majority of patients were treated with newer oral antipsychotics; a substantial number required treatment with 2 or more medications. Most patients did not have objective signs of agitation (eg, hypertension or tachycardia) prior to medication administration. Administration of multiple medications was associated with a longer length of stay in the ED, as was parenteral administration of antipsychotics.
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Papers by Shaun Carstairs