Level of consciousness as a predictor of complications following tricyclic overdose

Review article: Emergency endotracheal intubation in non-traumatic brain pathologies: A systematic review and meta-analysis

Endotracheal intubation is an advanced airway procedure performed in the ED and the out-of-hospital setting for acquired brain injuries that include non-traumatic brain pathologies such as stroke, encephalopathies, seizures and toxidromes. Controlled trial evidence supports intubation in traumatic brain injuries, but it is not clear that this evidence can be applied to non-traumatic brain pathologies. We sought to analyse the impact of emergency intubation on survival in non-traumatic brain pathologies and also to quantify the prevalence of intubation in these pathologies. We conducted a systematic literature search of Medline, Embase and the Cochrane Library. Eligibility, data extraction and assessment of risk of bias were assessed independently by two reviewers. A bias-adjusted meta-analysis using a quality-effects model pooled prevalence of intubation in non-traumatic brain pathologies. Forty-six studies were included in this systematic review. No studies were suitable for meta-analysis the primary outcome of survival. Thirty-nine studies reported the prevalence of intubation in non-traumatic brain pathologies and a meta-analysis showed that emergency intubation was used in 12% (95% CI 0-33) of pathologies. Endotracheal intubation was used commonly in haemorrhagic stroke 79% (95% CI 47-100) and to a lesser extent for seizures 18% (95% CI 10-27) and toxidromes 25% (95% CI 6-48). This systematic review shows that there is no high-quality clinical evidence to support or refute emergency intubation in non-traumatic brain pathologies. Our analysis shows that intubation is commonly used in non-traumatic brain pathologies, and the need for rigorous evidence is apparent.

Amitriptyline-induced ventricular tachycardia: a case report

Background

In Bangladesh, each emergency physician faces amitriptyline overdose nearly a day. An acute cardiovascular complication, one of the worst complications is mainly responsible for the mortality in tricyclic overdose. Recently, we managed ventricular tachycardia in a young female presented with an impaired consciousness 10 h after intentionally ingesting 2500 mg amitriptyline. Here, we report it, discuss how the electrocardiography is vital to acknowledge and predict it and its’ complications and also the recent update of the management of it.

Case presentation

A young married Bangladeshi-Bengali girl, 25-year-old, having a history of disharmony with her husband, came with an impaired consciousness after intentionally ingesting 2500 mg amitriptyline about 10 h before arrival. There was blood pressure 140/80 mmHg, heart rate 140 beats-per-min, temperature 103 °F, Glasgow coma scale 10/15, wide complex tachycardia with QRS duration of 178 ms in electrocardiography, blood pH 7.36. Initially, treated with 100 ml 8.4% sodium bicarbonate. After that, QRS duration came to 100 ms in electrocardiography within 10 min of infusion. To maintain the pH 7.50–7.55 over the next 24 h, the infusion of 8.4% sodium bicarbonate consisting of 125 ml dissolved in 375 ml normal saline was started and titrated according to the arterial blood gas analysis. Hence, a total dose of 600 mmol sodium bicarbonate was given over next 24 h. In addition to this, gave a 500 ml intravenous lipid emulsion over 2 h after 24 h of admission as she did not regain her consciousness completely. Afterward, she became conscious, though, in electrocardiography, ST/T wave abnormality persisted. So that, we tapered sodium bicarbonate infusion slowly and stopped it later. At the time of discharge, she was by heart rate 124/min, QRS duration 90 ms in electrocardiogram along with other normal vital signs.

Conclusion

Diagnosis of amitriptyline-induced ventricular tachycardia is difficult when there is no history of an overdose obtained. Nevertheless, it should be performed in the clinical background and classic electrocardiographic changes and wise utilization of sodium bicarbonate, intravenous lipid emulsion, and anti-arrhythmic drugs may save a life.

Predicting the Need for Medical Intensive Care Monitoring in Drug-Overdosed Patients

Drug overdose (OD) is one of the most common single diagnoses admitted to medical intensive care units (MICUs). The diagnosis results in relatively little morbidity or mortality, suggesting a need to improve the methods utilized in deciding on MICU admission. Our objective in this study was to develop a quantitative system whereby the emergency room (ER) physician, with reasonable safety and ease, would be able to discriminate between the need for an ICU and a nonmonitored bed. We reviewed the charts of 216 consecutive MICU admissions for intentional OD involving 199 patients between the years 1995 and 1998. Clinical histories, vital signs, laboratory data inclusive of toxicologic analysis, and both APACHE II and Glasgow coma scores (GCS) were assessed from the ER and on transfer to the MICU 4–6 hours later. These scores, as well as individual components of the APACHE II score, were evaluated for significance. Of 216 admissions reviewed, 75 (35%) had MICU-requiring morbidity: intubation 61%, pneumonia 20%, arrhythmia or EKG changes 20%, and hypotension 3%. Mortality was 2.7%. The remaining admissions were for ICU monitoring due to lethargy, irritability, laboratory abnormalities, or simply based on the diagnosis of drug overdose. Urine examinations for drugs were positive in only 53%, with the most common agent identified being benzodiazepines (39%). Age, Apache II score, and GCS were significantly different between those patients who developed MICU-requiring morbidity and those who did not, as well as when comparing the morbidity with the mortality group. Receiver operator control (ROC) curves reveal that both the APACHE and GCS are excellent and equal predictors of morbidity, with a GCS of ≤ 12 having 88% sensitivity and 92% specificity in predicting MICU-requiring morbidity. We conclude that ER evaluation of GCS can be used to accurately assess and predict the need for MICU monitoring in drug overdose. OD patients with a persistent GCS of greater than 12 or who do not demonstrate any hemodynamic, infectious, or electrocardiographic complications in the ER do not require MICU admission.

Cyclic Antidepressant Poisoning: A Review and Case Report

Although newer cyclic antidepressants have been introduced over the past several years, the tricyclic antidepressants (TCAs) continue to be the leading cause of morbidity from drug overdose in the United States. Overdose features depend on the particular cyclic antidepressant ingested and its pharmacological properties, and can include CNS depression, cardiac arrhythmias, hypotension, seizures, and anticholinergic symptomatology. Life-threatening symptomatology almost always begins within 2 hours, and certainly within 6 hours, after arrival to the emergency department. Plasma TCA levels are unreliable predictors of TCA toxicity and are not recommended. An ECG with a prolonged QRS complex more than 100 msec seems to be the best indicator of serious sequelae with TCAs. Management consists of stabilization of vital signs, gastrointestinal decontamination, intravenous sodium bicarbonate, and supportive care. Agents once thought to be useful for the treatment of cardiac dysrhythmias and seizures such as phenytoin and physostigmine should be avoided. The future of TCA antibody fragments in the treatment of TCA overdose seems promising. Newer and, to some degree, safer antidepressants in overdose have recently been introduced, and they include fluoxetine, trazodone, and sertraline. Amoxapine, bupropion, and maprotiline seem to be as toxic as the TCAs. A significant interaction between cyclic antidepressants and monoamine-oxidase inhibitors exists. Management includes supportive care and basic poison management. Prevention of poisoning seems to be the most logical and effective method of maintaining patient safety. TCAs should be avoided in children younger than 6 years old. All adults with suicidal ideations should receive no more than a 1-week supply (about 1 g) of drug. Finally consideration should be given to using one of the newer, safer antidepressants in all patients with suicidal ideations.

Self-poisonings with tricyclic antidepressants and selective serotonin reuptake inhibitors in Tehran, Iran

In a prospective hospital-based cohort study, we addressed the question of severity and outcome of antidepressant poisonings in patients who attended the Loghman-Hakim Hospital Poison Center, the only national center in Tehran dedicated for detoxification. The aim of the study was to find out if tricyclic antidepressant (TCA) intoxications require more therapeutic efforts than selective serotonin reuptake inhibitor (SSRI) intoxications. The study was applied over a 7-week period (28 March-20 May 2006). From 3578 intoxications, 334 patients with antidepressant or lithium self-poisoning were identified (9.3% of all poisoning cases; 233 females, 101 males; median age 24 years, min 13, max 70). Compared to SSRI single-substance intoxications (n=17), TCA single-substance intoxications (n=73) were associated with: (1) a significantly lower level of consciousness (P=0.005); (2) a significantly higher admission frequency (80.8 vs. 35.3%; P<0.001); and (3) a higher intubation frequency (13.7 vs. 0%; P=ns). SSRI multiple-substance intoxications were associated with a significantly lower level of consciousness than SSRI single-substance intoxications (P=0.042), while there was no significant difference between TCA multiple- and single-substance intoxications. This study suggests that an overdose with SSRIs results in a more favourable clinical outcome than an overdose with TCAs.

Poisoning severity score, APACHE II and GCS: effective clinical indices for estimating severity and predicting outcome of acute organophosphorus and carbamate poisoning

Self-poisoning with organophosphorus (OP) compounds is a major cause of morbidity and mortality across South Asian countries. To develop uniform and effective management guidelines, the severity of acute OP poisoning should be assessed through scientific methods and a clinical database should be maintained. A prospective descriptive survey was carried out to assess the utility of severity scales in predicting the outcome of 71 organophosphate (OP) and carbamate poisoning patients admitted during a one year period at the Kasturba Hospital, Manipal, India. The Glasgow coma scale (GCS) scores, acute physiology and chronic health evaluation II (APACHE II) scores, predicted mortality rate (PMR) and Poisoning severity score (PSS) were estimated within 24h of admission. Significant correlation (P<0.05) between PSS and GCS and APACHE II and PMR scores were observed with the PSS scores predicting mortality significantly (P< or =0.001). A total of 84.5% patients improved after treatment while 8.5% of the patients were discharged with severe morbidity. The mortality rate was 7.0%. Suicidal poisoning was observed to be the major cause (80.2%), while other reasons attributed were occupational (9.1%), accidental (6.6%), homicidal (1.6%) and unknown (2.5%) reasons. This study highlights the application of clinical indices like GCS, APACHE, PMR and severity scores in predicting mortality and may be considered for planning standard treatment guidelines.

Serial Monitoring of Lead aVR in Patients with Prolonged Unconsciousness Following Tricyclic Antidepressant Overdose

Severe cardiac and neurologic toxicities of tricyclic antidepressant (TCA) overdose have been reported since the introduction of TCAs in 1950s. Despite the decreased numbers of TCA overdoses, the mortality and morbidity rates of TCA overdose have remained constantly high. Clinical manifestations of TCA overdose are characterized by unconsciousness and specific electrocardiography (ECG) abnormalities such as prolongation of the PR and QTc intervals, widening of the QRS duration, and an increased R wave and R/S ratio in lead aVR. We report a case with unusually prolonged unconsciousness without initial stem reflexes for 7 days and multiple ECG abnormalities following TCA overdose. It is suggested that the serial monitoring of R wave and R/S ratio in lead aVR might be informative in predicting recovery from toxicity following TCA overdose.

Tricyclic antidepressant poisoning: an evidence-based consensus guideline for out-of-hospital management

A review of U.S. poison center data for 2004 showed over 12,000 exposures to tricyclic antidepressants (TCAs). A guideline that determines the conditions for emergency department referral and prehospital care could potentially optimize patient outcome, avoid unnecessary emergency department visits, reduce healthcare costs, and reduce life disruption for patients and caregivers. An evidence-based expert consensus process was used to create the guideline. Relevant articles were abstracted by a trained physician researcher. The first draft of the guideline was created by the lead author. The entire panel discussed and refined the guideline before distribution to secondary reviewers for comment. The panel then made changes based on the secondary review comments. The objective of this guideline is to assist poison center personnel in the appropriate prehospital triage and management of patients with suspected ingestions of TCAs by 1) describing the manner in which an ingestion of a TCA might be managed, 2) identifying the key decision elements in managing cases of TCA ingestion, 3) providing clear and practical recommendations that reflect the current state of knowledge, and 4) identifying needs for research. This guideline applies to ingestion of TCAs alone. Co-ingestion of additional substances could require different referral and management recommendations depending on their combined toxicities. This guideline is based on the assessment of current scientific and clinical information. The panel recognizes that specific patient care decisions may be at variance with this guideline and are the prerogative of the patient and the health professionals providing care, considering all the circumstances involved. This guideline does not substitute for clinical judgment. Recommendations are in chronological order of likely clinical use. The grade of recommendation is in parentheses. 1) Patients with suspected self-harm or who are the victims of malicious administration of a TCA should be referred to an emergency department immediately (Grade D). 2) Patients with acute TCA ingestions who are less than 6 years of age and other patients without evidence of self-harm should have further evaluation including standard history taking and determination of the presence of co-ingestants (especially other psychopharmaceutical agents) and underlying exacerbating conditions, such as convulsions or cardiac arrhythmias. Ingestion of a TCA in combination with other drugs might warrant referral to an emergency department. The ingestion of a TCA by a patient with significant underlying cardiovascular or neurological disease should cause referral to an emergency department at a lower dose than for other individuals. Because of the potential severity of TCA poisoning, transportation by EMS, with close monitoring of clinical status and vital signs en route, should be considered (Grade D). 3) Patients who are symptomatic (e.g., weak, drowsy, dizzy, tremulous, palpitations) after a TCA ingestion should be referred to an emergency department (Grade B). 4) Ingestion of either of the following amounts (whichever is lower) would warrant consideration of referral to an emergency department: an amount that exceeds the usual maximum single therapeutic dose or an amount equal to or greater than the lowest reported toxic dose. For all TCAs except desipramine, nortriptyline, trimipramine, and protriptyline, this dose is >5 mg/kg. For despiramine it is >2.5 mg/kg; for nortriptyline it is >2.5 mg/kg; for trimipramine it is >2.5 mg/kg; and for protriptyline it is >1 mg/kg. This recommendation applies to both patients who are naïve to the specific TCA and to patients currently taking cyclic antidepressants who take extra doses, in which case the extra doses should be added to the daily dose taken and then compared to the threshold dose for referral to an emergency department (Grades B/C). 5) Do not induce emesis (Grade D). 6) The risk-to-benefit ratio of prehospital activated charcoal for gastrointestinal decontamination in TCA poisoning is unknown. Prehospital activated charcoal administration, if available, should only be carried out by health professionals and only if no contraindications are present. Do not delay transportation in order to administer activated charcoal (Grades B/D). 7) For unintentional poisonings, asymptomatic patients are unlikely to develop symptoms if the interval between the ingestion and the initial call to a poison center is greater than 6 hours. These patients do not need referral to an emergency department facility (Grade C). 8) Follow-up calls to determine the outcome for a TCA ingestions ideally should be made within 4 hours of the initial call to a poison center and then at appropriate intervals thereafter based on the clinical judgment of the poison center staff (Grade D). 9) An ECG or rhythm strip, if available, should be checked during the prehospital assessment of a TCA overdose patient. A wide-complex arrhythmia with a QRS duration longer than 100 msec is an indicator that the patient should be immediately stabilized, given sodium bicarbonate if there is a protocol for its use, and transported to an emergency department (Grade B). 10) Symptomatic patients with TCA poisoning might require prehospital interventions, such as intravenous fluids, cardiovascular agents, and respiratory support, in accordance with standard ACLS guidelines (Grade D). 11) Administration of sodium bicarbonate might be beneficial for patients with severe or life-threatening TCA toxicity if there is a prehospital protocol for its use (Grades B/D). 12) For TCA-associated convulsions, benzodiazepines are recommended (Grade D). 13) Flumazenil is not recommended for patients with TCA poisoning (Grade D).

What Does Ultrasonography Miss in Blunt Trauma Patients With A Low Glasgow Coma Score (GCS)?

BACKGROUND

The role of ultrasound (US) as a screening tool for the evaluation of blunt abdominal trauma is still controversial. Determining the types of missed injuries and the accuracy of US in patients with a low GCS will improve the evaluation of these blunt trauma patients.

METHODS

Prospectively collected data from the trauma registry of a Level I trauma center was reviewed.

RESULTS

7,952 patients were included in the study. US examination had an accuracy of 89%, sensitivity of 77%, specificity of 97%, positive predictive value (PPV) of 78%, and negative predictive value (NPV) of 98%. GCS correlated with ISS and base deficit levels. US examination had a significantly lower accuracy in patients with a low GCS and in women.

CONCLUSION

The sensitivity and specificity of US examination is similar in those with normal and low GCS. Therefore ultrasonographic examination may be considered a good screening tool for the evaluation of patients with blunt abdominal trauma, but its accuracy is diminished in patients with a low GCS. Further imaging may be warranted in these patients.

Tricyclic antidepressant poisoning : cardiovascular toxicity

Tricyclic antidepressants remain a common cause of fatal drug poisoning as a result of their cardiovascular toxicity manifested by ECG abnormalities, arrhythmias and hypotension. Dosulepin and amitriptyline appear to be particularly toxic in overdose. The principal mechanism of toxicity is cardiac sodium channel blockade, which increases the duration of the cardiac action potential and refractory period and delays atrioventricular conduction. Electrocardiographic changes include prolongation of the PR, QRS and QT intervals, nonspecific ST segment and T wave changes, atrioventricular block, right axis deviation of the terminal 40 ms vector of the QRS complex in the frontal plane (T 40 ms axis) and the Brugada pattern (downsloping ST segment elevation in leads V1-V3 in association with right bundle branch block). Maximal changes in the QRS duration and the T 40 ms axis are usually present within 12 hours of ingestion but may take up to a week to resolve. Sinus tachycardia is the most common arrhythmia due to anticholinergic activity and inhibition of norepinephrine uptake by tricyclic antidepressants but bradyarrhythmias (due to atrioventricular block) and tachyarrhythmias (supraventricular and ventricular) may occur. Torsade de pointes occurs uncommonly. Hypotension results from a combination of reduced myocardial contractility and reduced systemic vascular resistance due to alpha-adrenergic blockade. Life-threatening arrhythmias and death due to tricyclic antidepressant poisoning usually occurs within 24 hours of ingestion. Rapid deterioration is common. Level of consciousness at presentation is the most sensitive clinical predictor of serious complications. Although a QRS duration >100 ms and a rightward T 40 ms axis appear to be better predictors of cardiovascular toxicity than the plasma tricyclic drug concentration, they have at best moderate sensitivity and specificity for predicting complications.

Chemically Induced Seizures

Drug- and toxin-associated seizures (DTS) may result from exposure to a wide variety of agents. Most DTS can be managed with supportive care. First-line anticonvulsant therapy should include benzodiazepines, unless agents require a specific antidote. Phenytoin is generally not expected to be useful for DTS and in some instances may be harmful. In this article the authors discuss the pathophysiology of DTS, the potential differential diagnosis, and the clinical presentation. They also review selected agents that cause DTS and provide an overview of how the clinician should approach the management of patients who have DTS.

Drug- and toxin-associated seizures

Drug- and toxin-associated seizures may result from exposure to a wide variety of agents. Obtaining a comprehensive history behind the exposure is generally more helpful than diagnostic testing. Most DTS may be managed with supportive care, including benzodiazepines, except in the case of agents that require a specific intervention or antidote.

Tricyclic Antidepressant Poisoning

All tricyclic drugs are potentially able to cause the main acute CNS toxic syndromes of coma and convulsions. Dosulepin (dothiepin) seems more likely to cause convulsions than other drugs in this class, and amitriptyline also appears a more toxic tricyclic agent. Coma is the most useful sign indicative of toxic risk and appears to predict severe toxic complications (fits and arrhythmias) more reliably than ECG changes. Prophylactic therapy against convulsions has not been shown to be effective. Use of an anticholinesterase (physostigmine) is not recommended for management of coma. There is no good evidence base to support a particular anticonvulsant.

A Meta‐Analysis of Prognostic Indicators to Predict Seizures, Arrhythmias or Death After Tricyclic Antidepressant Overdose

OBJECTIVES

To systematically review and summarize studies on the accuracy of ECG and tricyclic antidepressant (TCA) concentration as prognostic indicators of the risk of seizures, ventricular arrhythmia (VA) or death in patients with TCA overdose.

METHODS

Articles were identified with MedLine and Cochrane register of controlled clinical trials searches and review of medical toxicology textbooks. Quality of the included studies was assessed. Pooled estimates of sensitivity, specificity, likelihood ratios and Summary Receiver Operating Characteristics (SROC) curves were generated.

RESULTS

A total of 18 studies were included in the analysis. The pooled sensitivity (Se) and specificity (Sp) of the QRS for predicting seizures were 0.69 [95% CI 0.57-0.78] and 0.69 [95% CI 0.58-0.78] as compared to 0.75 [95% CI 0.61-0.85] and 0.72 [95% CI 0.61-0.81] for the TCA concentration. The Se and Sp of the QRS to predict VA were 0.79 [95% CI 0.58-0.91] and 0.46 [95% CI 0.35-0.59] compared to 0.78 [95% CI 0.56-0.90] and 0.57 [95% CI 0.46-0.67] for the TCA concentration. The Se and Sp of the QRS to predict death were 0.81 [95% CI 0.54-0.94] and 0.62 [95% CI 0.55-0.68] compared to 0.76 [95% CI 0.49-0.91] and 0.60 [95% CI 0.47-0.72] for the TCA concentration. Very few studies evaluated the accuracy of QTc, T 40 ms axis and the R/S ratio.

CONCLUSIONS

Overall, the studies suggested that the ECG and TCA concentration have similar but relatively poor performance for predicting complications, such as seizures, VA or death, associated with TCA overdose.

ED utilization of computed tomography in a poisoned population

The objective of this prospective, analytic study was to identify predictors and describe the demographic and clinical correlates of head computed tomography (CT) evaluation in patients with poisoning or drug overdose and altered mental status. Forty-three patients that were evaluated by head CT and 109 that were not evaluated by head CT were entered into the study at a poison control center. None of the 43 scanned patients had any acute findings on head CT. A logistic regression model yielded 4 predictors that were statistically associated with the ordering of a head CT scan: Glasgow Coma Scale (GCS) < or = 8 (odds ratio [OR]: 2.3; 95% confidence interval [CI] 1.03-5.7); age > or = 41 years (OR 5.3; 95% CI 2.2-13); use of drugs or abuse by history (OR 2.8; 95% CI 1.04-7.6); and witnessed seizure activity (OR 4.8; 95% CI 1.3-17.9). We also tested 2 additional models to identify predictors of hospital admission, 1 with and 1 without CT scan included as a covariate. In the first model, only GCS </=8 was a significant predictor of admission (OR 10.7; 95% CI 2.4-47.2). When the use of head CT was added to the second model, it also emerged as an independent explanatory predictor of admission (OR 4.8; CI 95% 1.2-20.4) in addition to GCS (OR 10.1; 95% CI 2.2-45.4). In this pilot study, patients presenting to the emergency department (ED) with suspected poisoning or drug overdose were found to have a low likelihood of abnormal findings on head CT scan. Those among whom CT scans were obtained were more likely to be admitted to the hospital from the ED, despite negative findings.

Comparison of APACHE II, MEES and Glasgow Coma Scale in patients with nontraumatic coma for prediction of mortality. Acute Physiology and Chronic Health Evaluation. Mainz Emergency Evaluation System

INTRODUCTION

There are numerous prehospital descriptive scoring systems, and it is uncertain whether they are efficient in assessing of the severity of illness and whether they have a prognostic role in the estimation of the illness outcome (in comparison with that of the prognostic scoring system Acute Physiology and Chronic Health Evaluation [APACHE] II). The purpose of the present study was to assess the value of the various scoring systems in predicting outcome in nontraumatic coma patients and to evaluate the importance of mental status measurement in relation to outcome.

PATIENTS AND METHODS

In a prehospital setting, postintervention values of the Mainz Emergency Evaluation System (MEES) and Glasgow Coma Scale (GCS) were measured for each patient. The APACHE II score was recorded on the day of admission to the hospital. This study was undertaken over a 2-year period (from January 1996 to October 1998), and included 286 consecutive patients (168 men, 118 women) who were hospitalized for nontraumatic coma. Patients younger than 16 years were not included. Their age varied from 16 to 87 years, with mean +/- standard deviation of 51.8 +/- 16.9 years. Sensitivity, specificity and correct prediction of outcome were measured using the chi2 method, with four severity scores. The best cutoff point in each scoring system was determined using the Youden index. The difference in Youden index was calculated using the Z score. For each score, the receiver operating characteristic (ROC) curve was obtained. The difference in ROC was calculated using the Z score. P < 0.05 was considered statistically significant.

RESULTS

For prediction of mortality, the best cutoff points were 19 for APACHE II, 18 for MEES and 5 for GCS. The best cutoffs for the Youden index were 0.63 for APACHE II, 0.61 for MEES and 0.65 for GCS. The correct prediction of outcome was achieved in 79.9% for APACHE II, 78.3% for MEES and 81.9% for GCS. The area under the ROC curve (mean +/- standard error) was 0.86 +/- 0.02 for APACHE II, 0.84 +/- 0.06 for MEES and 0.88 +/- 0.03 for GCS. There were no statistically significant differences among APACHE II, MEES and GCS scores in terms of correct prediction of outcome, Youden index or area under ROC curve.

CONCLUSIONS

APACHE II is not much better than prehospital descriptive scoring systems (MEES and GCS). APACHE II and MEES should not replace GCS in assessment of illness severity or in prediction of mortality in nontraumatic coma. For the assessment of mortality, the GCS score provides the best indicator for these patients (simplicity, less time-consuming and effective in an emergency situation.

Antidepressant Poisoning and Treatment: A Review and Case Illustration

Although newer antidepressants have been introduced over the past several years, the tricyclic antidepressants (TCAs) continue to be a leading cause of morbidity from drug overdose in the United States. Overdose features depend on the particular cyclic antidepressant ingested and its pharmacological properties, and can include CNS depression, cardiac dysrhythmias, hypotension, seizures, and anticholinergic symptoms. Life-threatening events almost always begin within two hours, and certainly within six hours, after arrival to the emergency department. Plasma TCA levels are unreliable predictors of TCA toxicity and are therefore not recommended. An ECG with a prolonged QRS complex more than 100 msec seems to be the best indicator of serious sequelae with TCA overdose. Management consists of stabilization of vital signs, gastrointestinal decontamination, intravenous sodium bicarbonate, and supportive care. Agents once thought to be useful for the treatment of cardiac dysrhythmias and seizures such as phenytoin and physostigmine should be avoided. The future of TCA antibody fragments in the treatment of TCA overdose seems promising. Amoxapine, bupropion, and maprotiline seems to be as toxic as the TCAs. Overdose data is limited for venlafaxine, and mirtazapine, and preclude firm conclusions. A significant interaction between cyclic antidepressants and monoamine-oxidase inhibitors exists. Management includes supportive care and basic poison management. Prevention of poisoning seems to be the most logical and effective method of maintaining patient safety. TCAs should be avoided in children younger than 6 years old. All adults with suicidal ideations should receive no more than a one-week supply (less than 1 g) of drug. Newer and, to some degree, safer antidepressants in overdose have recently been introduced, and they include fluoxetine, sertraline, paroxetine, trazodone, and nefazodone. Finally, consideration should be given to using one of these newer, safer antidepressants in all patients with suicidal ideations.

Evaluation of the Glasgow Coma Scale score in critically ill infectious disease patients

In this prospective study the Glasgow Coma Scale (GCS) score was evaluated in 107 critically ill infectious disease (ID) patients admitted to the Intensive Care Unit (ICU) during a 1-year period. Patients were separated into two groups: those affected by central nervous system (CNS) infections and those affected by infections other than of the CNS. There were no apparent differences in the first ICU day GCS score values between the two groups (11 +/- 4 vs. 11 +/- 4, p = 0.5318). Univariate logistic regression analysis confirmed a significant relationship between the first ICU day GCS score and the subsequent ICU mortality in the group of patients with CNS infections (r = 0.3152, p = 0.0015) but not in the group with infections not affecting the CNS (r = 0.0919, p = 0.1106). Our preliminary results suggest that the prognostic value of the GCS score is valid only in patients with CNS infections but not in other ID patients.

Intentional drug overdose: predictors of clinical course in the intensive care unit

OBJECTIVE

To examine the characteristics of patients admitted to the Medical Intensive Care Unit (MICU) after intentional drug overdose.

DESIGN

Retrospective chart review, descriptive.

SETTING

Midwestern teaching hospital.

SUBJECTS

Convenience sample of 43 patients admitted to the MICU after intentional drug overdose.

OUTCOME MEASURES

Survival and disposition of those patients who survived and were discharged from the MICU.

RESULTS

Ninety-five percent of the patients survived and were discharged from the MICU; Acute Physiology and Chronic Health Evaluation II scores ranged from 1 to 29 (mean, 8); Glascow Coma Scale scores ranged from 3 to 15 (mean 12.5); five patients were intubated and two patients had serious electrocardiograph changes requiring pharmacologic intervention for dysrhythmia.

CONCLUSIONS

Neurologic findings were the best indicators of serious complications after drug overdose. THerefore, patients with a Glascow Coma Scale score of more than six, and who are not intubated, may not need admission to an intensive care unit.

Cardiovascular repercussions of seizures during cyclic antidepressant poisoning

Cyclic antidepressant overdose involves a risk of generalized seizures and cardiovascular disturbances. We have conducted a retrospective study to test the hypothesis of a relationship between generalized seizures and the onset of arrhythmia, hypotension or cardiac arrest during cyclic antidepressant intoxication. Patients who had seizures after ingestion of toxic amounts of tri- or tetracyclic antidepressants were included. Limb-lead QRS complex duration and systolic blood pressure were recorded before and after seizure. Twenty-four of the 388 patients (6.2%) who were admitted to our ICU over a four-year period had seizures (2.3 +/- 2 seizures/patient). Cardiac repercussions of cyclic-induced seizure were frequent and severe. In the postictal period, broadening of the QRS duration or hypotension occurred or were exacerbated in at least 41% and 29% of cases, respectively. In three patients (12.5%), the seizure-induced cardiovascular state was life-threatening and required massive alkalinization therapy and vasopressors, and two of the three required cardiac massage or cardioversion. Prior to seizure, these three patients had severe intoxications characterized by QRS duration > or = 120 ms and systolic blood pressure < or = 80 mm Hg. The results of this work confirm the potential risk of cardiovascular deterioration after cyclic antidepressant-induced seizure and raise the question of a prophylactic approach especially towards the subgroup with unstable hemodynamic status.

Cyclic antidepressant overdose: a review of current management strategies

Cyclic antidepressant (CA) overdose can produce life-threatening seizures, hypotension, and dysrhythmias. It accounts for up to half of all overdose-related adult intensive care unit admissions and is the leading cause of death from drug overdose in patients arriving at the emergency department alive. Several factors contribute to the significant morbidity and mortality associated with CA overdose. First, CAs are widely prescribed and are dispensed to patients at increased risk for attempting suicide. Second, drugs of this class generally have a low therapeutic toxic ratio. Third, in the majority of fatal cases, the patient dies before reaching a hospital. Finally, and of greatest significance for the clinician, the presenting signs and symptoms of CA overdose may be missed by the physician, even in cases of severe toxicity. Therefore, CAs must be considered early in any case of suspected overdose, and all such cases should be managed as potentially fatal ones. The following case demonstrates the current approach to the patient with significant CA toxicity.

Severe amitriptyline overdose: relationship between toxicokinetics and toxicodynamics

The clinical features and toxicokinetics of amitriptyline were studied in nine patients with severe amitriptyline poisoning. Amitriptyline and amitriptyline metabolites were studied in plasma, red blood cells, and cerebral spinal fluid. Eight patients were intubated and six required assisted ventilation. Two patients had ventricular arrhythmias, three patients convulsions and two were hypotensive. All complications developed within four hours of admission. Early in the course of the intoxication the QRS duration correlated with plasma, unbound and red blood cell nortriptyline concentration. The QRS duration also correlated with unbound but not the plasma amitriptyline concentration. The level of consciousness correlated with the plasma and unbound amitriptyline both in alpha and beta phase and with red blood cell amitriptyline in alpha phase. There was no correlation between nortriptyline concentration and level of consciousness. No correlation between coma grade or QRS duration and cerebral spinal fluid concentration of amitriptyline was found. There was no correlation between any hydroxymetabolite in blood or cerebral spinal fluid and QRS duration or coma grade. The beta half-life for amitriptyline was shorter for two patients with high concentrations of hydroxymetabolites. Although intubated, neither patient required assisted ventilation or developed complications. Because of the wide range of concentrations of amitriptyline and amitriptyline metabolites observed between individuals, it is not possible to predict outcome based on a single tricyclic antidepressant concentration.

Predicting severity of tricyclic antidepressant overdose

The measurement of plasma concentration, a prolonged QRS interval, and level of consciousness have all been recommended as useful indicators of toxicity following tricyclic antidepressant overdose. The aims of this study were firstly, to determine the relative prognostic value of each of these indicators and secondly, to assess when a patient can be discharged safely from the intensive care unit. Data were evaluated on 67 patients with tricyclic antidepressant overdose from four centers. Plasma tricyclic antidepressant concentrations were measured, coma grade was evaluated using the Matthew-Lawson Coma Scale and a ECG was obtained from 23 patients on admission. Complications such as convulsions, hypotension, arrhythmias, and need for intubation and ventilation were recorded. Thirty patients developed complications and no patient died. Coma grade was the best predictor of outcome. The development of serious complications is unlikely in patients whose level of consciousness is grade II or less and who are admitted to hospital more than 6 h after overdose. Plasma tricyclic antidepressant concentration was of no additional value in predicting toxic complications or deciding when the patient could leave the intensive care unit. Our study suggests that an alert and orientated patient with a QRS duration less than 100 ms is the best indicator for safe transfer to a medical or psychiatric ward.

Tricyclic antidepressant poisoning

OBJECTIVE

To review poisoning with tricyclic antidepressants.

DATA SOURCE

English language literature search using Australian Medlars Service (1977-1989), manual search of journals and review of bibliographies in identified articles.

STUDY SELECTION

Approximately 250 articles, abstracts and book chapters were selected for analysis.

DATA EXTRACTION

The literature was reviewed and 93 articles were selected as representative of important advances.

DATA SYNTHESIS

The major features of overdose are neurological, cardiac, respiratory and anticholinergic. Life-threatening complications develop within six hours of overdose or not at all. All patients seen within six hours of overdose should have their stomachs emptied. All patients should receive activated charcoal. Coma, convulsions, respiratory depression and hypotension are treated with standard resuscitation techniques and drugs. Treat patients with significant cardiotoxicity or cardiac arrest with alkalinisation by sodium bicarbonate or hyperventilation, aiming for an arterial pH of 7.45-7.55. Lignocaine is used for ventricular arrhythmias. Other antiarrhythmic drugs are contraindicated (Class 1A, Class 1C), potentially lethal (Class II), of no benefit (phenytoin) or of unproven efficacy (Class III and Class IV). Physostigmine has no role at all. Haemodialysis and haemoperfusion are of no benefit.

CONCLUSION

The death rate of those who reach hospital is 2%-3%. Most of these deaths are cardiac in origin, and are caused by direct depression of myocardial function rather than cardiac arrhythmias.

Severity grading in self-poisoning

1. The reliability and validity of three different coma scales was studied in 26 patients with acute drug overdose. 2. A comparison of six painful stimulation techniques showed that sternal rubbing and retromandibular pressure were most effective. 3. The improper use of stimulation techniques may underestimate level of responsiveness in 4-19% of cases. 4. The Reaction Level Scale (RLS) was the most reliable scale. 5. Both the RLS and the Glasgow Coma Scale may be unnecessarily complicated for the evaluation of the drug overdose patient, but should be chosen if concomitant brain injury is suspected. 6. This study confirms the basic concepts and shows the reliability of the Matthew-Lawson scale for use in the poisoned patient.