Evaluation of the validity of the Done nomogram in the management of acute salicylate intoxication

Development and validation of a risk prediction nomogram for disposition of acute clozapine intoxicated patients to intensive care unit

BACKGROUND

Clozapine is an atypical antipsychotic drug used for the treatment of refractory schizophrenia. It is reported as the most toxic in its class. Using serum clozapine level as a severity indicator is doubtful and unfeasible, particularly in low resourced countries.

METHODS

This is an extended two-phase retrospective study that utilized medical records of patients diagnosed with acute clozapine intoxication and admitted to Tanta University Poison Control Center, Egypt during the past 6 years. Two hundred and eight medical records were used to establish and validate a nomogram for predicting the need for intensive care unit (ICU) admission in acute clozapine intoxicated patients.

RESULTS

A reliable simple bedside nomogram was developed and proved its significant ability to predict the need for ICU admission, with an area under the curve (AUC) of 83.9% and 80.8% accuracy. It encompassed the age of admitted patients (AUC = 64.8%, p = .003), respiratory rate (AUC = 74.7%, p < .001), O₂ saturation (AUC = 71.7%, p < .001), and random blood glucose level upon admission (AUC = 70.5%, p < .001). External validation of the proposed nomogram showed a high AUC (99.2%) with an overall accuracy of 96.2%.

CONCLUSION

There is a need to develop a reliable objective tool predicting the severity and need for ICU admission in acute clozapine intoxication. The proposed nomogram is a substantially valuable tool to estimate ICU admission probabilities among patients with acute clozapine intoxication and will help clinical toxicologists make rapid decisions for ICU admission, especially in countries with low resources.

Prognostic indicators in critically ill poisoned patients: development of a risk-prediction nomogram

OBJECTIVES

The prognosis of acutely poisoned patients is a significant concern for clinical toxicologists. In this study, we sought to determine the clinical and laboratory findings that can contribute to predicting the medical outcomes of poisoned patients admitted to intensive care units (ICUs).

METHODS

This retrospective study was performed from January 2009 to January 2016 in the ICU of Vali-e-Asr Hospital in Birjand, Iran. We included all patients with the diagnosis of acute poisoning admitted to the ICU. Demographic data, laboratory results, the Sequential Organ Failure Assessment (SOFA), and acute physiology score + age points + chronic health points (APACHE) II, and the Simplified Acute Physiology Score (SAPS) II, and outcome were collected. Univariate analysis (Mann-Whitney or t-test), multiple logistic regression, receiver operating characteristics (ROC) curve analysis, and Pearson's correlation test were performed using SPSS, STATA/SE 13.0, and Nomolog software programs.

RESULTS

The multiple logistic regression analysis revealed that five factors were significant for predicting mortality including age (OR 95% CI: 1.1[1.05-1.12], p<0.001), Glasgow Coma Score (GCS) (OR 95% CI: 0.71[0.6-0.84], p<0.001), white blood cell (WBC) count (OR 95% CI: 1.1[1.01-1.12], p=0.04), serum sodium (Na) (OR 95% CI: 1.08[1.01-1.15], p=0.02), and creatinine levels (Cr) (OR 95% CI: 1.86 [1.23-2.81], p=0.003). We generated a five-variable risk-prediction nomogram which could both predict mortality risk and identify high-risk patients.

CONCLUSIONS

Age, GCS, WBC, serum creatinine, and sodium levels are the best prognostic factors for mortality in poisoned patients admitted to the ICU. The APACHE II score can discriminate between non-survivors and survivors. The nomogram developed in the current study can provide a more precise, quick, and simple analysis of risks, thereby enabling the users to predict mortality and identify high-risk patients.

Prognostic indicators in critically ill poisoned patients: development of a risk-prediction nomogram

Objectives The prognosis of acutely poisoned patients is a significant concern for clinical toxicologists. In this study, we sought to determine the clinical and laboratory findings that can contribute to predicting the medical outcomes of poisoned patients admitted to intensive care units (ICUs). Methods This retrospective study was performed from January 2009 to January 2016 in the ICU of Vali-e-Asr Hospital in Birjand, Iran. We included all patients with the diagnosis of acute poisoning admitted to the ICU. Demographic data, laboratory results, the Sequential Organ Failure Assessment (SOFA), and acute physiology score + age points + chronic health points (APACHE) II, and the Simplified Acute Physiology Score (SAPS) II, and outcome were collected. Univariate analysis (Mann-Whitney or t-test), multiple logistic regression, receiver operating characteristics (ROC) curve analysis, and Pearson's correlation test were performed using SPSS, STATA/SE 13.0, and Nomolog software programs. Results The multiple logistic regression analysis revealed that five factors were significant for predicting mortality including age (OR 95% CI: 1.1[1.05-1.12], p<0.001), Glasgow Coma Score (GCS) (OR 95% CI: 0.71[0.6-0.84], p<0.001), white blood cell (WBC) count (OR 95% CI: 1.1[1.01-1.12], p=0.04), serum sodium (Na) (OR 95% CI: 1.08[1.01-1.15], p=0.02), and creatinine levels (Cr) (OR 95% CI: 1.86 [1.23-2.81], p=0.003). We generated a five-variable risk-prediction nomogram which could both predict mortality risk and identify high-risk patients. Conclusions Age, GCS, WBC, serum creatinine, and sodium levels are the best prognostic factors for mortality in poisoned patients admitted to the ICU. The APACHE II score can discriminate between non-survivors and survivors. The nomogram developed in the current study can provide a more precise, quick, and simple analysis of risks, thereby enabling the users to predict mortality and identify high-risk patients.

Prognostic Factors in Acute Aluminium Phosphide Poisoning: A Risk-Prediction Nomogram Approach

Aluminium phosphide (AlP) is a toxic agent associated with a high mortality rate following acute exposure from various routes. The aim of this study was to determine the clinical and laboratory findings useful for predicting the medical outcome of AlP-poisoned patients using established scoring systems. This is a prospective study of AlP-poisoned patients from 2010 to 2015 in Ardabil, Iran. All patients that presented with a confirmed diagnosis of acute AlP poisoning in the study interval were included in the study. Clinical and laboratory data, using Acute Physiology and Chronic Health Evaluation II (APACHE II), Sequential Organ Failure Assessment (SOFA) and Simplified Acute Physiology Score II (SAPS II) scoring systems, were compared for their predictive value in determining differences between survived and non-survived patients. Univariate analysis (Mann-Whitney or t-test), multiple logistic regression analysis, receiver operating characteristic (ROC) curve analysis and the Pearson correlation test were performed using STATA/SE 13.0 and the Nomolog Software. A total of 68 AlP-poisoned patients with confirmed acute AlP poisoning were included for evaluation. Of these, 36 were non-survived. Multiple logistic regression analysis was performed using parameters and values derived from patient clinical and laboratory data, and revealed that four factors were significant for predicting mortality: Glasgow coma score (GCS); systolic blood pressure (SBP); urinary output (UOP); and serum HCO₃ . A four-variable, risk-prediction nomogram was developed for identifying high-risk patients and predicting the risk of mortality. Study results showed that SBP of <92.5 mmHg (p = 0.006); HCO₃^- < 12.9 mEq/L (p = 0.01), UOP < 1725 mL/day (p = 0.04); and GCS < 14.5 (p = 0.003) were significant predictors of AlP mortality. Scoring systems analysis showed SAPS II score >24.5, APACHE II score >8.5 and SOFA score >7.5 were predictive of non-survival patients. The results of our study showed that SBP, GCS, UOP and serum HCO₃ levels are the best prognostic factors for predicting mortality in AlP-poisoned patients. According to the area under the ROC curve of the APACHE II score, when compared with SOFA and SAPS II scores, the APACHE II score can more effectively discriminate between non-survivors and survived patients.

Development and validation of a risk-prediction nomogram for in-hospital mortality in adults poisoned with drugs and nonpharmaceutical agents: An observational study

Acute poisoning with drugs and nonpharmaceutical agents represents an important challenge in the emergency department (ED).The objective is to create and validate a risk-prediction nomogram for use in the ED to predict the risk of in-hospital mortality in adults from acute poisoning with drugs and nonpharmaceutical agents.This was a prospective cohort study involving adults with acute poisoning from drugs and nonpharmaceutical agents admitted to a tertiary referral center for toxicology between January and December 2015 (derivation cohort) and between January and June 2016 (validation cohort). We used a program to generate nomograms based on binary logistic regression predictive models. We included variables that had significant associations with death. Using regression coefficients, we calculated scores for each variable, and estimated the event probability. Model validation was performed using bootstrap to quantify our modeling strategy and using receiver operator characteristic (ROC) analysis. The nomogram was tested on a separate validation cohort using ROC analysis and goodness-of-fit tests.Data from 315 patients aged 18 to 91 years were analyzed (n = 180 in the derivation cohort; n = 135 in the validation cohort). In the final model, the following variables were significantly associated with mortality: age, laboratory test results (lactate, potassium, MB isoenzyme of creatine kinase), electrocardiogram parameters (QTc interval), and echocardiography findings (E wave velocity deceleration time). Sex was also included to use the same model for men and women. The resulting nomogram showed excellent survival/mortality discrimination (area under the curve [AUC] 0.976, 95% confidence interval [CI] 0.954-0.998, P < 0.0001 for the derivation cohort; AUC 0.957, 95% CI 0.892-1, P < 0.0001 for the validation cohort).This nomogram provides more precise, rapid, and simple risk-analysis information for individual patients acutely exposed to drugs and nonpharmaceutical agents, and accurately estimates the probability of in-hospital death, exclusively using the results of objective tests available in the ED.

Acute salicylate poisoning: risk factors for severe outcome

CONTEXT

Salicylate poisoning remains a significant public health threat with more than 20,000 exposures reported annually in the United States.

OBJECTIVE

We aimed to establish early predictors of severe in-hospital outcomes in Emergency Department patients presenting with acute salicylate poisoning.

METHODS

This was a secondary data analysis of adult salicylate overdoses from a prospective cohort study of acute drug overdoses at two urban university teaching hospitals from 2009 to 2013. Patients were included based on confirmed salicylate ingestion and enrolled consecutively. Demographics, clinical parameters, treatment and disposition were collected from the medical record. Severe outcome was defined as a composite occurrence of acidemia (pH <7.3 or bicarbonate <16 mEq/L), hemodialysis, and/or death.

RESULTS

Out of 1997 overdoses screened, 48 patients met inclusion/exclusion criteria. Patient characteristics were 43.8% male, median age 32 (range 18-87), mean initial salicylate concentration 28.1 mg/dL (SD 26.6), and 20.8% classified as severe outcome. Univariate analysis indicated that age, respiratory rate, lactate, coma, and the presence of co-ingestions were significantly associated with severe outcome, while initial salicylate concentration alone had no association. However, when adjusted for salicylate concentration, only age (OR 1.13; 95% CI 1.02-1.26) and respiratory rate (OR 1.29; 95% CI 1.02-1.63) were independent predictors. Additionally, lactate showed excellent test characteristics to predict severe outcome, with an optimal cutpoint of 2.25 mmol/L (78% sensitivity, 67% specificity).

CONCLUSIONS

In adult Emergency Department patients with acute salicylate poisoning, independent predictors of severe outcome were older age and increased respiratory rate, as well as initial serum lactate, while initial salicylate concentration alone was not predictive.

Delayed salicylate toxicity following enteric-coated acetylsalicylic acid overdose: a case report and review of the literature

Salicylates are widely available and potentially lethal. Clinical and laboratory findings associated with enteric-coated acetylsalicylic acid (ECASA) ingestion may be delayed more than 24 hours. When dealing with patients who have a history of significant ingestion, emergency physicians should consider initiating therapy regardless of initial salicylate levels. Prolonged observation may be necessary in cases of suspected ECASA overdose.

Extracorporeal Treatment for Salicylate Poisoning: Systematic Review and Recommendations From the EXTRIP Workgroup

STUDY OBJECTIVE

Salicylate poisoning is a challenging clinical entity associated with substantial morbidity and mortality. The indications for extracorporeal treatments such as hemodialysis are poorly defined. We present a systematic review of the literature along with evidence- and consensus-based recommendations on the use of extracorporeal treatment in salicylate poisoning.

METHODS

The Extracorporeal Treatments in Poisoning (EXTRIP) Workgroup is a multidisciplinary group with international representation whose aim is to provide evidence-based recommendations on the use of extracorporeal treatments in poisoning. We conducted a systematic literature review followed by data extraction and summarized findings, following a predetermined format. The entire work group voted by a 2-round modified Delphi method to reach consensus on voting statements, using a RAND/UCLA Appropriateness Method to quantify disagreement. Anonymous votes were compiled, returned, and discussed in person. A second vote determined the final recommendations.

RESULTS

Eighty-four articles met inclusion criteria, including 1 controlled clinical trial, 3 animal studies, and 80 case reports or case series, yielding an overall very low quality of evidence for all recommendations. Clinical data on 143 patients (130 sets of which could be analyzed for patient-level entry data), including 14 fatalities, were reviewed. Toxicokinetic data on 87 patients were also included. After the second round of voting, the workgroup concluded that salicylates are dialyzable by hemodialysis and hemoperfusion (level of evidence=B) and recommended extracorporeal treatment in patients with severe salicylate poisoning (1D), including any patient with altered mental status (1D), with acute respiratory distress syndrome requiring supplemental oxygen (1D), and for those in whom standard therapy is deemed to be failing (1D) regardless of the salicylate concentration. High salicylate concentrations warrant extracorporeal treatment regardless of signs and symptoms (>7.2 mmol/L [100 mg/dL] [1D]; and >6.5 mmol/L [90 mg/dL] [2D]), with lower thresholds applied for patients with impaired kidney function (>6.5 mmol/L [90 mg/dL] [1D]; >5.8 mmol/L [80 mg/dL] [2D]). Extracorporeal treatment is also suggested for patients with severe acidemia (pH ≤7.20 in the absence of other indications) (2D). Intermittent hemodialysis is the preferred modality (1D), although hemoperfusion (1D) and continuous renal replacement therapies (3D) are acceptable alternatives if hemodialysis is unavailable, as is exchange transfusion in neonates (1D).

CONCLUSION

Salicylates are readily removed by extracorporeal treatment, with intermittent hemodialysis being the preferred modality. The signs and symptoms of salicylate toxicity listed warrant extracorporeal treatment, as do high concentrations regardless of clinical status.

Sudden-onset tachypnea and confusion in a previously healthy teenager

Acute intoxication with acetylsalicylic acid is a severe event commonly seen in children resulting from wide availability of this drug without prescription. Cases of self-poisoning resulting from overdose continue to occur and, although far less common, they are often severe and life-threatening. We report a 14-year-old girl who presented to the emergency department with tachypnea and altered mental status as a result of acetylsalicylic acid overdose in a suicide attempt. We discuss her presentation and the pathophysiological considerations leading to the management decisions taken during her emergency department stay, highlighting the role of the clinician and therapeutic drug monitoring consultant. The use of rapid decontamination with multiple doses of charcoal, even when more than 4 hours have passed since ingestion, and the use of urinary alkalinization are stressed. Timely management can obviate the need for dialysis. Published cases of acetylsalicylic acid intoxication are reviewed.

Dialysis in the poisoned patient

Patients who ingest toxic substances may require extracorporeal removal of the poisons or their toxic metabolites if native renal clearance is not sufficient because of acute kidney injury, acuity of symptoms, or burden of toxin. Here, a case is presented, and the literature on renal replacement therapy in the event of acute intoxication is reviewed. Extracorporeal therapy efficacy is examined in terms of the characteristics of the toxin (molecular size, charge, protein, or lipid binding); the patient (body habitus and volume of distribution); and the process (membrane effects on extraction ratios and sieving, role of blood, and dialysate flow rates). The choice of extracorporeal therapy and hemodialysis prescriptions for specific poisonings are discussed.

Emergency department management of the salicylate-poisoned patient

Salicylate toxicity continues to be encountered commonly in emergency medicine. This article portrays the signs and symptoms of salicylate toxicity, reviews the erratic absorption and elimination kinetics, describes the devastating physiologic effects of overdose, and illustrates the potentially subtle manifestations of chronic aspirin toxicity.

Are one or two dangerous? Methyl salicylate exposure in toddlers

Serious toxicity can result from exposure to small amounts of methyl salicylate. Methyl salicylate is widely available as a component in many over-the-counter brands of creams, ointments, lotions, liniments and medicated oils intended for topical application to relieve musculoskeletal aches and pains. Among the most potent forms of methyl salicylate is oil of wintergreen (98% methyl salicylate). Other products with varying concentrations of methyl salicylate are ubiquitous throughout many parts of the world, including a number of products marketed as Asian herbal remedies. The toxic potential of all of these formulations is often underestimated by health care providers and the general public. A comprehensive review of the existing medical literature on methyl salicylate poisoning was performed, and data compiled over the past two decades by the American Association of Poison Control Centers (AAPCC) was examined. Methyl salicylate continues to be a relatively common source of pediatric exposures. Persistent reports of life-threatening and fatal toxicity were found. In children less than 6 years of age, a teaspoon (5 mL) or less of oil of wintergreen has been implicated in several well-documented deaths. More needs to be done to educate both health care providers and the general public regarding the dangers of these widely available formulations.

Deadly ingestions

More than 50% of the toxic-exposure calls to US poison centers involve children. Although most of these exposures are nontoxic, there are several products and medications that are widely available to the pediatric population that can lead to severe toxicity or even death. With some of these medications, death or severe symptoms can occur with the ingestion of only a small amount. It is important that the clinician be familiar with presenting signs and symptoms of potentially toxic ingestions and is able to initiate a therapeutic and life-saving intervention. This article reviews some of the deadlier ingestions that children may be exposed to.

Utilizing the Laboratory in the Poisoned Patient

This article examines the role of common laboratory tests in the evaluation of a poisoned patient. Numerous laboratory tests maybe useful to clinicians caring for poisoned patients. Clinicians should not order a broad range of tests indiscriminately, but rather thoughtfully consider appropriate tests. The results of the tests should be reviewed in the context of the clinical scenario.

Utilizing diagnostic investigations in the poisoned patient

Numerous diagnostic tests may be useful to clinicians caring for poisoned patients. Clinicians should not order a broad range of tests indiscriminately,but rather thoughtfully consider appropriate tests. The results'of the tests should be reviewed in the context of the clinical scenario.

Toxicology in the critically ill patient

Intoxications present in many forms including: known drug overdose or toxic exposure, illicit drug use, suicide attempt, accidental exposure, and chemical or biological terrorism. A high index of suspicion and familiarity with toxidromes can lead to early diagnosis and intervention in critically ill, poisoned patients. Despite a paucity of evidence-based information on the management of intoxicated patients, a rational and systematic approach can be life saving.

National academy of clinical biochemistry laboratory medicine practice guidelines: recommendations for the use of laboratory tests to support poisoned patients who present to the emergency department

BACKGROUND

Exposure to drugs and toxins is a major cause for patients' visits to the emergency department (ED).

METHODS

Recommendations for the use of clinical laboratory tests were prepared by an expert panel of analytical toxicologists and ED physicians specializing in clinical toxicology. These recommendations were posted on the world wide web and presented in open forum at several clinical chemistry and clinical toxicology meetings.

RESULTS

A menu of important stat serum and urine toxicology tests was prepared for clinical laboratories who provide clinical toxicology services. For drugs-of-abuse intoxication, most ED physicians do not rely on results of urine drug testing for emergent management decisions. This is in part because immunoassays, although rapid, have limitations in sensitivity and specificity and chromatographic assays, which are more definitive, are more labor-intensive. Ethyl alcohol is widely tested in the ED, and breath testing is a convenient procedure. Determinations made within the ED, however, require oversight by the clinical laboratory. Testing for toxic alcohols is needed, but rapid commercial assays are not available. The laboratory must provide stat assays for acetaminophen, salicylates, co-oximetry, cholinesterase, iron, and some therapeutic drugs, such as lithium and digoxin. Exposure to other heavy metals requires laboratory support for specimen collection but not for emergent testing.

CONCLUSIONS

Improvements are needed for immunoassays, particularly for amphetamines, benzodiazepines, opioids, and tricyclic antidepressants. Assays for new drugs of abuse must also be developed to meet changing abuse patterns. As no clinical laboratory can provide services to meet all needs, the National Academy of Clinical Biochemistry Committee recommends establishment of regional centers for specialized toxicology testing.

Delayed toxidromes

Some toxins do not result in clinical manifestations until several hours after exposure. This article reviews those agents that may cause delayed-onset toxicity. They are organized into four classes: specific pharmaceuticals, biologicals, pharmaceutical dosage forms, and chemicals. There are five basic mechanisms for delayed toxicity: delayed absorption, distribution factors, metabolic factors, cellular and organ capacity effects, and unknown. Scientific evidence for delayed-onset of effects varies considerably among the individual toxins.

Standards of laboratory practice: analgesic drug monitoring

Analgesics are the most commonly consumed over-the-counter preparations in the United States. They are used in the treatment of various pain syndromes and other medical conditions. Although analgesics are generally perceived to be safe agents, serious toxicity may occur in the setting of acute overdose, chronic abuse, or overuse. The indications for therapeutic drug monitoring in patients using these medications appropriately is as yet not well defined. The emphasis of this discussion, therefore, is on recommendations for monitoring in situations where toxicity is suspected. Preanalytical, analytical, and practice issues including drug interactions, frequency of monitoring, pertinent ancillary tests, reporting, and special patient groups at risk for toxicity are reviewed. Recent information from a major manufacturer of evacuated tubes arguing against the use of gel tubes for blood collection for drug monitoring is included. Colorimetric/enzymatic/immunoassays for the routine/stat monitoring of acetaminophen and salicylate and diflunisal cross-reactivity with most of the currently used salicylate assays are presented. Achiral and chiral chromatographic assays and newly introduced columns such as restricted access media and/or automated chromatographic systems are reviewed for the analysis of ibuprofen, naproxen, and the recently introduced tramadol. Finally, concepts regarding future directions including drug chirality and chiral analysis are presented.

Approach to the poisoned patient

Routine poison management involves the following: (1) stabilization, (2) toxidrome recognition, (3) decontamination, (4) antidote administration, (5) enhanced elimination of toxin, and (6) supportive care. Stabilization involves airway, ventilation, and circulation support. In the patient with altered mental status, oxygen, naloxone, glucose, and thiamine should be administered. Symptom complexes that relate to specific classifications of toxins are referred to as toxidromes. Emesis by means of syrup of ipecac is rarely used for in-hospital gastric decontamination. Activated charcoal is a useful adsorbent for gastric decontamination. Whole bowel irrigation is useful for iron, lead, and lithium poisoning and for the body packer phenomenon. Enhancement of elimination may involve multiple doses of activated charcoal, hemodialysis, or charcoal hemoperfusion.