Incidence and risk factors for hyperlactatemia in ED patients with acute metformin overdose

INTRODUCTION

The goals of this study are to describe clinical characteristics and risk factors for metabolic acidosis with hyperlactatemia in emergency department (ED) patients with acute metformin overdose.

METHODS

This was a secondary analysis of data from a retrospective observational cohort of adult ED patients presenting with acute drug overdose at two tertiary care hospitals over 5 years. The primary outcomes were: (1) hyperlactatemia, defined as a lactate concentration ≥ 2 mmol/L at any point during hospital admission and, (2) metformin associated lactic acidosis (MALA), defined as a lactate concentration ≥ 5 mmol/L and pH <7.35 at any point during hospital admission.

RESULTS

We screened 3739 acute overdoses; 2872 met eligibility, 56 self-reported metformin overdose (57% female, mean age 55.8). Of these, 39 had measured lactate values. There was a high incidence of hyperlactatemia (56.4%); MALA was less frequent (17.9%). There were no deaths. Low serum bicarbonate was an independent clinical risk factor for hyperlactatemia (adjusted p < 0.05). Acetaminophen co-exposure was an independent clinical risk factor for MALA (OR 24.40, 95% CI 1.6-376.4).

CONCLUSIONS

In ED patients with acute metformin overdose, initial hyperlactatemia is common but MALA is unusual. Acetaminophen co-exposure is a novel independent risk factor for the occurrence of MALA that deserves further investigation.

Rebound metabolic acidosis following intentional amygdalin supplement overdose

Introduction: Amygdalin, marketed misleadingly as supplement "Vitamin B17," is a cyanogenic glycoside. When swallowed, it is hydrolyzed into cyanide in the small intestine, which causes histotoxic hypoxia via inhibition of cytochrome c oxidase. It remains available for purchase online despite a ban from the US Food and Drug Administration. We report a case of massive intentional amygdalin overdose resulting in recurrent cyanide toxicity after initial successful antidotal therapy.Case summary: A 33-year-old woman intentionally ingested 20 g of "apricot POWER B17 Amygdalin" supplements. She presented five hours post-ingestion with vital signs: P 127 bpm, BP 112/65 mmHg, RR 25/min, temperature 98.1 °F, and SpO2 98% RA. She was in agitated delirium, diaphoretic, and mydriatic. Her VBG was notable for a pH of 7.27 (rr 7.32-7.42) and lactate 14.1 mmol/L (rr 0.5-2.2), with ECG demonstrating QTc 538 ms (normal <440 ms). She was empirically treated with hydroxocobalamin and supportive care, but worsened clinically, requiring intubation and additional hydroxocobalamin and sodium thiosulfate, which resolved her toxicity. Twelve hours later, she developed recurrent hypotension, acidemia, and QTc prolongation that resolved with repeat hydroxocobalamin and sodium thiosulfate dosing.Discussion: Our case demonstrates rebound metabolic acidosis after massive amygdalin overdose. Toxicity was associated with prolonged QTc, which warrants further investigation into clinical significance. Redosing of combination antidotal therapy suggested efficacy without adverse effects.

Poison control centers and alternative forms of communicating with the public: what's all the chatter about?

Context: Short messaging service (SMS or text messaging) allows for the exchange of electronic text messages. Online chatting refers to Internet-based transmission of messages for real-time conversation. Poison Control Centers (PCCs) in the United States communicate with the public primarily via telephone. However, people increasingly prefer the convenience of SMS and chatting. Our objective is to describe the use of SMS and chatting by PCCs in the United States. Methods: An electronic survey questionnaire was distributed to all 55 US poison control center members of the American Association of Poison Control Centers. The survey assessed protocols for SMS and chatting, inquiry volume, and staff satisfaction. Centers reporting use of SMS or chatting services were administered follow-up questions, which further documented SMS and chatting interfaces and startup and maintenance costs. Descriptive statistics were used to describe the data. No statistical analysis was performed. Results: Of the 55 PCCs, 51 (93%) responded to the survey, 6 (12%) of which currently use or formerly used SMS and/or chatting. Inquiry volume ranged from 0 to 1 per day for SMS and 0 to 20 per day for chats. Startup costs ranged from $0 to $25,000. The most beneficial aspect, reported by 4 of the 6 PCCs (66.6%), was providing an alternative contact for inquiries. Most SMS and chatting interactions were completed within 10 and 30 min, respectively. All six centers completed telephone interactions within 10 min. The most disadvantageous aspects, reported by 2 of the 6 PCCs (33.3%), were staff apprehension and interaction length. Technology, such as syncing with existing call queuing software and databases, presented the greatest barrier to implementation. Conclusions: A minority of PCCs in the United States use SMS and chatting. Further research may investigate the economic feasibility of these systems, if SMS and chatting effectively expands public access, and patient comfort in contacting PCCs.

Racial disparities in the treatment of acute overdose in the emergency department

OBJECTIVES

Racial and ethnic disparities in the United States continue to exist in many disciplines of medicine, extending to care in the Emergency Department (ED). We sought to examine the relationship between patient race/ethnicity and use of either antidotal therapy or gastrointestinal decontamination for individuals presenting to the ED for acute drug overdose.

METHODS

We completed a secondary analysis of a prospective cohort of patients with suspected acute overdose presenting to two urban tertiary care hospitals between 2009 and 2014. Race was self-identified during ED registration. Antidote administration (primary outcome) and gastrointestinal decontamination (secondary outcome) were reviewed and verified via agreement between two board certified medical toxicologists. Associations between race and outcomes were analyzed using a logistic regression model.

RESULTS

We reviewed 3252 ED patients with acute overdose. Overall, 542 people were treated with an antidote and 234 cases were treated with activated charcoal, either single or multiple dose. Compared to Whites, Blacks and Hispanics were significantly less likely to receive any antidote. The analysis was underpowered to detect racial disparities in the administration of activated charcoal.

CONCLUSIONS

Blacks and Hispanics are significantly less likely to receive any antidote when presenting to the ED for acute drug overdose. Further studies are needed to determine national prevalence of this apparent disparity in care and to fully characterize how race plays a role in management of acute overdose.

Extracorporeal treatments in poisonings from four non-traditionally dialysed toxins (acetaminophen, digoxin, opioids and tricyclic antidepressants): A combined single-centre and national study

The use of extracorporeal treatments (ECTRs) for poisonings with four non-traditionally dialysed toxins (NTDTs) is increasing in the United States. This study evaluated whether ECTRs are prescribed for toxin removal or the treatment of other medical illnesses or complications. We performed a 2-Phase retrospective analysis evaluating the main indication for ECTRs in patients with poisoning from a NTDT (defined for this study as acetaminophen, opioids, tricyclic antidepressants (TCAs) or digoxin) and ECTR. The first phase assessed all cases from a single site (New York City Poison Control Center) between the years 2000 and 2016, and the second phase surveyed all United States Poison Control Centers (PCCs). In Phase 1, demographics, toxin ingested and main indication for ECTR were extracted. In Phase 2, a query to the National Poison Data System using the a pragmatic subset of inclusion criteria from Phase 1 restricted to single toxin ingestions over a narrower time frame (2014-2016) provided the cases for study. A structured online questionnaire was sent to all United States PCCs to request their database review regarding the indication for ECTR for their cases. In Phase 1, 92 cases met inclusion criteria. In Phase 2, 519 cases were screened and 425 met inclusion criteria. In Phase 1 91/92 (98.9%) and Phase 2 411/425 (96.7%), of extracorporeal treatments were used to treat underlying medical conditions or poisoning-related complications rather than accelerate toxin removal. The increasing number of ECTRs reported in patients who ingested one of the four NTDTs thus appears to be for medical indications rather than attempts at toxin removal, a distinction that is important.

Prognostic Utility of Initial Lactate in Patients With Acute Drug Overdose: A Validation Cohort

STUDY OBJECTIVE

Previous studies have suggested that the initial emergency department (ED) lactate concentration may be an important prognostic indicator for inhospital mortality from acute drug poisoning. We conduct this cohort study to formally validate the prognostic utility of the initial lactate concentration in a larger, distinct patient population with acute drug overdose.

METHODS

This observational, prospective, cohort study was conducted during 5 years at 2 urban teaching hospitals. Consecutive adult ED patients with acute drug overdose had serum lactate levels tested as part of clinical care. The primary outcome was inpatient fatality. Receiver operating characteristics were plotted to determine optimal cut points, test characteristics, area under the curve, odds ratios, and 95% confidence intervals (CIs).

RESULTS

Of 3,739 patients screened, 1,406 were analyzed (56% women; mean age 43.1 years) and 24 died (1.7%). The difference in mean initial lactate concentration was 5.9 mmol/L (95% CI 3.4 to 8.1 mmol/L) higher in patients who died compared with survivors. The area under the curve for prediction of fatality was 0.85 (95% CI 0.73 to 0.95). The optimal lactate cut point for fatality was greater than or equal to 5.0 (odds ratio 34.2; 95% CI 13.7 to 84.2; 94.7% specificity). Drug classes for which lactate had the highest utility were salicylates, sympathomimetics, acetaminophen, and opioids (all area under the curve ≥0.97); lowest utility was for diuretics and angiotensin-converting enzyme inhibitors.

CONCLUSION

Initial lactate concentration is a useful biomarker for early clinical decisionmaking in ED patients with acute drug overdose. Studies of lactate-tailored management for these patient populations are warranted.