Pulmonary complications after tricyclic antidepressant overdose

Endotracheal Intubation in the Pharmaceutical-Poisoned Patient: a Narrative Review of the Literature

INTRODUCTION

Endotracheal intubation (ETI) is an essential component of the supportive care provided to the critically ill patient with pharmaceutical poisoning; however, specific nuances surrounding intubation including techniques and complications in the context of pharmaceutical poisoning have not been well elucidated.

DISCUSSION

A search of the available literature on ETI in pharmaceutical-poisoned patients was undertaken using Medline, ERIC, Cochrane database, and PsycINFO using the following MeSH and keyword terms: ("toxicology" OR "poisons" OR "drug overdose" OR "poisoning") AND ("intubation, intratracheal" OR "intubation, endotracheal" OR "airway management" OR "respiration, artificial"). A hand-search was also performed when the literature in the above search required additional conceptual clarification, including using the "Similar Articles" feature of PubMed, along with reviewing articles' reference lists that discussed intubation in the context of a poisoning scenario. Articles with any discussion around the ETI process in the context of a pharmaceutical poisoning were then included. Intubation may be performed in patients poisoned with pharmaceuticals in the context of both single and multiple organ dysfunction including central and peripheral nervous system, pulmonary, or cardiovascular toxicity with hemodynamic instability, or localized effects resulting in mechanical airway obstruction. Certain classes of poisonings may require modifications to the standard rapid sequence induction airway management algorithm.

CONCLUSIONS

ETI is a key component of the supportive care provided to the patient poisoned by a pharmaceutical agent. Clinicians should be aware of the spectrum of toxicities that can necessitate intubation, as well as airway management nuances that are specific to various poisoning presentations.

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.

Critical Role of Central Facilitation in the Glottic Closure Reflex

The sphincteric function of the larynx, essential to lower airway protection, is most efficiently achieved through strong reflex adduction by both vocal cords. We hypothesize that central facilitation is an essential component of a bilateral adductor reflex and that its disturbance could result in weakened sphincteric closure. Six adult 50-kg pigs underwent evoked response laryngeal electromyography under 0.5 to 1.0 minimal alveolar concentration (MAC) isoflurane anesthesia. The internal branch of the superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes, and recording electrodes were positioned in the ipsilateral and contralateral thyroarytenoid muscles. Consistent threshold responses were obtained ipsilaterally from 0.5 to 1.0 MAC anesthesia. However, the contralateral reflex responses approached 0% in successive trials as anesthetic levels approached 1.0 MAC. Alteration of central facilitation by deepening anesthesia abolishes the crossed adductor reflex, predisposing to a weakened glottic closure response. A precise understanding of this effect may improve the prevention of aspiration in patients emerging from prolonged sedation or under heavy psychotropic control.

Radionuclide Salivagram and Gastroesophageal Reflux Scintigraphy in Pediatric Patients: Targeting Different Types of Pulmonary Aspiration

OBJECTIVE

Both gastroesophageal reflux (GER) scintigraphy and radionuclide salivagram are commonly used in the detection of pulmonary aspiration in pediatric patients. This investigation is to compare the diagnostic value of these 2 imaging methods.

METHODS

This retrospective study included 4186 pediatric patients (aged 1 week to 16 years; mean age, 28 months) who underwent a GER scintigraphy and/or radionuclide salivagram. Detection rate of pulmonary aspiration by the 2 imaging techniques was compared.

RESULTS

The detection rate for pulmonary aspiration in patients undergoing both procedures was 1.9% (5 of 266) for GER scintigraphy and 22.2% (59 of 266) for radionuclide salivagram. Fifty-six of 59 patients with proven aspiration on radionuclide salivagram demonstrated no such findings on GER scintigraphy, whereas 2 of 5 patients with proven aspiration on GER scintigraphy demonstrated no such findings on radionuclide salivagram. In patients who underwent only 1 procedure (either GER scintigraphy or salivagram), the detection rate for pulmonary aspiration was 0.4% (15 of 3551) for GER scintigraphy and 20.3% (75 of 369) for radionuclide salivagram.

CONCLUSIONS

Radionuclide salivagram showed a much higher detection rate for pulmonary aspiration compared with GER scintigraphy. However, this may be related to a significantly higher prevalence of antegrade versus retrograde aspiration in our study population. Our results also suggest that not all episodes of retrograde aspiration can be detected by a radionuclide salivagram, and the requested scan should be tailored to the type of suspected aspiration.

Availability of treatment resources for the management of acute toxic exposures and poisonings in emergency departments among various types of hospitals in Palestine: a cross-sectional study

BACKGROUND

Poisoning exposures continue to be a significant cause of morbidity and mortality worldwide. The lack of facilities, treatment resources, and antidotes in hospitals may affect the treatments provided and outcomes. This study aimed to determine the availability of gastrointestinal (GI) decontamination, stabilisation, elimination enhancement resources, and antidotes for the management of acute toxic exposures and poisonings in emergency departments (EDs) among various types of governmental and private hospitals in Palestine.

METHODS

A cross-sectional study using semi-structured questionnaire was performed. Data were collected based on hospital resources; GI decontamination, stabilisation, elimination enhancement resources and antidotes from Palestinian hospitals.

RESULTS

Eighteen hospitals (94.7%) have responded. Among them, paracetamol poisoning was the most frequently reported cases by EDs (mean frequency score = 7.6 ± 2.1), followed by bee stings (mean = 6.9 ± 2.7) and organophosphate poisoning (mean = 6.7 ± 2.7). The availabilities of most resources related to GI decontamination items varied substantially with hospital type, but these differences were not statistical significant. The availability of stabilisation resources was not significantly different between hospitals types. For the availability of techniques used to enhance the elimination of toxic substances, there were variations between the hospitals types. However, these differences were not statistical significant, except for haemodialysis (p = 0.003) which was more available in governmental hospitals. For the availability of antidotes, none of the hospitals had sufficient stock of all antidotes listed. In relation to hospital type, there was variability in the availability of antidotes, but this did not reach statistical significance, except for deferoxamine (p < 0.001), which was available in all governmental hospitals but none of the private hospitals.

CONCLUSIONS

The availability of treatment resources and antidotes in Palestinian hospitals was not adequate except for stabilisation resources. The availability of such resources acts as a marker for the level of readiness of hospital EDs in Palestine for the management of acute toxic exposure and poisoning. The implementation of a minimum list of antidotes and treatment resources would be useful to increase the level of resources. Coordination between Palestinian poison control and drug information centre and hospitals is also important.

"Pills" and the air passages

Aspiration of a medication in the airways in any form produces a variety of adverse effects, both local and systemic. Furthermore, specific reaction of the airways to each type of pill strongly affects the outcome. It is crucial for pulmonologists and emergency medicine specialists to acknowledge this clinical entity. In addition, airways have been increasingly used to deliver medications such as insulin and prostacycline. These aerosolized medications can also cause local as well as systemic side effects. We review the local and systemic reactions of these "pills" accessing the airways either by incidental aspiration or iatrogenic administration. We address clinical presentation, mechanism of injury, diagnosis, and management of complications of these pills in the air passages.

Availability of decontamination, elimination enhancement, and stabilization resources for the management of acute toxic exposures and poisonings in emergency departments in Malaysia

Acute poisoning is a common medical emergency in Malaysia. Life can be saved if the patient is diagnosed properly and receives the appropriate treatment such as gastrointestinal decontamination techniques and resources to increase poison elimination according to clinical guidelines at a reasonable time. The aims of this study were to determine the availability of decontamination, elimination enhancement, and stabilization resources for the management of acute toxic exposures and poisonings in accident and emergency departments in Malaysia, and to compare the availability of such facilities among various types of hospitals. A comparative, descriptive cross-sectional study was conducted using a structured questionnaire. Seventy-four (58.3%) out of the targeted 127 hospitals replied and completed the questionnaire. The availabilities of most items related to stabilization resources were far better in general hospitals compared to district hospitals with specialists and district hospitals without specialists. These items were mechanical ventilators (p = 0.011), non-invasive positive pressure ventilators (0.024), pacemakers (p = 0.019), and transcutaneous cardiac pacing (p < 0.001). The availability of decontamination resources varied substantially with hospital type. Nevertheless, these differences did not reach statistical significance in any of the cases, whereas sodium sulphate, sorbitol, and polyethylene glycol were almost never available. The availabilities of most items related to elimination enhancement resources were far better in general hospitals and district hospitals with specialists compared to district hospitals without specialists. These items were haemodialysis (p = 0.046), haemoperfusion (p = 0.002), haemofiltration (p = 0.002), acid diuresis (p = 0.04), peritoneal dialysis (p < 0.001), and exchange transfusion (p < 0.001). Most Malaysian hospitals have certain important immediate interventions such as gastrointestinal decontamination techniques and resources to increase poison elimination. The availabilities of most facilities were far better in the general hospitals. Coordination between the National Poison Centre in Malaysia and hospitals should be established regarding the emergency facilities for effective management of poisoning cases in each hospital in order to direct the poisoned patients to the hospital where the appropriate management resources is available.

Characteristics of glottic closure reflex in a canine model

PURPOSE

The most important function of the larynx is airway protection which is provided through a polysynaptic reflex closure triggered by the receptors in the glottic and supraglottic mucosa, evoking the reflex contraction of the laryngeal muscles especially by strong adduction of vocal cords. Based on the hypotheses that central facilitation is essential for this bilateral adductor reflex and that its disturbance can result in weakened laryngeal closure, we designed this study to elucidate the effect of central facilitation on this protective reflex.

MATERIALS AND METHODS

Seven adult, 20 kg mongrel dogs underwent evoked response laryngeal electromyography under 0.5 to 1.0 MAC (minimum alveolar concentration) isoflurane anesthesia. The internal branch of the superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes, and recording electrodes were positioned in the ipsilateral and contralateral thyroarytenoid muscles.

RESULTS

Ipsilateral reflex closure was consistently recorded regardless of anesthetic levels. However, contralateral reflex responses disappeared as anesthetic levels were deepened. Additionally, late responses (R2) were detected in one animal at lower level of anesthesia.

CONCLUSIONS

Deepened level of anesthesia affects central facilitation and results in the loss of the crossed adductor reflex, predisposing to a weakened glottic closure response. Precise understanding of this effect may possibly provide a way to prevent aspiration in unconscious patients.

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).

[Pulmonary abcess, a revision]

Lung abscesses are cavitating lesions containing necrotic debris caused by microbial infection. Patients with chronic lung disease, bronchial obstruction secondary to cancer, a history of aspiration or risk of aspiration caused by alcoholism, altered mental status, structural or physiologic alterations of the pharynx and esophagus, neuromuscular disorders, anesthesia, are among others at higher risk of developing lung abcess. The main bacteriological characteristics, the diagnosis, therapy and prognosis are considered. The problem of antimicrobial resistance is also referred.

Effects of altered consciousness on the protective glottic closure reflex

OBJECTIVES

The sphincteric function of the larynx, essential to lower airway protection, is most efficiently achieved through strong reflex adduction by both vocal folds. We hypothesize that central facilitation is an essential component of a bilateral brain stem-mediated adductor reflex and that its disturbance by altered consciousness or physiologic sleep could result in weakened sphincteric closure.

METHODS

In 10 adult pigs the glottic closure response was evaluated under light and deep isoflurane anesthesia. The internal branch of the left superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes, and recording electrodes were positioned in the ipsilateral and contralateral thyroarytenoid muscles. The force of evoked glottic closure was measured with a pressure transducer positioned between the vocal folds.

RESULTS

Consistent threshold responses (>90%) were obtained ipsilaterally from 0.5 to 2.0 minimal alveolar concentration (MAC) anesthesia. However, the contralateral reflex responses declined to 6.4% in successive trials as anesthetic levels approached 1.5 to 2.0 MAC. Furthermore, glottic closing force closely reflected these electromyographic changes, declining from 383 mm Hg at 0.5 to 1.0 MAC to 114 mm Hg at 1.5 to 2.0 MAC.

CONCLUSIONS

Alteration of central facilitation by progressively deeper loss of consciousness abolishes a lower brain stem-mediated crossed adductor reflex, predisposing the subject to a weakened glottic closure response.

Incidence, risk factors, and outcome of aspiration pneumonitis in ICU overdose patients

OBJECTIVE

To assess the incidence and outcome of clinically significant aspiration pneumonitis in intensive care unit (ICU) overdose patients and to identify its predisposing factors.

DESIGN

Retrospective cohort study.

SETTING

Medical ICU of an academic tertiary care hospital.

PATIENTS

A total of 273 consecutive overdose admissions.

MEASUREMENTS AND RESULTS

Clinically significant aspiration pneumonitis was defined as the occurrence of respiratory dysfunction in a patient with a localised infiltrate on chest X-ray within 72 h of admission. In our cohort we identified 47 patients (17%) with aspiration pneumonitis. Importantly, aspiration pneumonitis was associated with a higher incidence of cardiac arrest (6.4 vs 0.9%; p = 0.037) and an increased duration of both ICU stay and overall hospital stay [respectively: median 1 (interquartile range 1-3) vs 1 (1-2), p = 0.025; and median 2 (1-7) vs 1 (1-3), p < 0.001]. In multivariate logistic regression analysis, Glasgow Coma Scale (GCS) score [odds ratio (OR) for each point of GCS 0.8; 95% confidence interval (CI) 0.7-0.9; p = 0.001], ingestion of opiates (OR 4.5; 95% CI 1.7-11.6; p = 0.002), and white blood cell count (WBC) (OR for each increase in WBC of 10(9)/l 1.05; 95% CI 1.0-1.19; p = 0.049) were identified as independent risk factors.

CONCLUSIONS

Clinically relevant aspiration pneumonitis is a frequent complication in overdose patients admitted to the ICU. Moreover, aspiration pneumonitis is associated with a higher incidence of cardiac arrest and increased ICU and total in-hospital stay.

Daily evaluation of macroaspiration in the critically ill post-trauma patient

BACKGROUND

Although critically ill trauma patients represent a high-risk population for macroaspiration, studies of trauma patients have not been explored. The study aims were to quantify rate and associated risks of macroaspiration and explore the pattern of antibiotic use and incidence of aspiration pneumonia within this patient group.

METHODS

Consecutive trauma patients admitted to the intensive care unit (ICU) were prospectively observed for development of macroaspiration and subsequent aspiration pneumonia. Daily monitoring included chart review, laboratory and radiography results, and nurse inquiries for witnessed macroaspiration events.

RESULTS

Seven of 60 patients included experienced a clinically confirmed macroaspiration event (11.7%). The incidence of pneumonia was similar, regardless of macroaspiration occurrence (28.6%: macroaspiration cases vs 17.0%: controls, p > or = 0.05). Patients with macroaspiration required a longer duration of mechanical ventilation (15 vs 9.5 days, p = 0.021) and intensive care unit stay (28 vs 7 days, p = 0.015). Paralytic agent utilization was associated with an increased risk for aspiration (p = 0.045).

CONCLUSIONS

The incidence of macroaspiration within a critically ill trauma population may be less frequent compared with studies performed in other patient populations. Although macroaspiration was associated with a longer duration of mechanical ventilation and intensive care unit stay, this condition may not be associated with an increased rate of pulmonary infection.

Alveolar plasminogen activator inhibitor-1 predicts ARDS in aspiration pneumonitis

OBJECTIVE

To test the hypothesis that alveolar plasminogen activator inhibitor-1 (PAI-1) can identify patients with witnessed aspiration at risk for progression to acute respiratory distress syndrome (ARDS).

DESIGN

Prospective observational study.

SETTING

Medical intensive care unit in a tertiary care center.

PATIENTS

Fifty-one patients with witnessed aspiration who had a PaO2/FIO2<300 for a period no less than 4 h from admission.

INTERVENTIONS

Alveolar fluid sampling was performed within 8 h of intubation via luminal suction of the distal airways using a 13-Fr catheter. Plasma levels were collected simultaneously by venipuncture.

MEASUREMENTS AND RESULTS

Alveolar PAI-1 antigen levels were more than five times higher in those who progressed to ARDS than in those with uncomplicated aspiration pneumonitis (2687+/-1498 ng/ml vs. 587+/-535 ng/ml, respectively; p<0.001), while plasma levels of PAI-1 antigen were not significantly different between the two groups. The measured activity of PAI-1 antigen paralleled the levels observed in both media. A cut-off level of alveolar PAI-1 >1518 ng/ml was found to be 82.4% (56.6%-96.0%) sensitive and 97.1% (84.6%-99.5%) specific in predicting progression to ARDS. There was also a significant inverse relationship between elevation of PAI-1 antigen levels and the degree of lung injury as assessed by the days of unassisted ventilation (r2=0.37; p<0.001).

CONCLUSIONS

Elevation of alveolar PAI-1 antigen levels postaspiration is the consequence of local rather than systemic activation of the fibrinolytic system. Measurement of alveolar PAI-1 antigen levels can be a useful clinical marker in predicting progression to ARDS after gastric aspiration.

Aspiration of gastric contents: association with prehospital intubation

We prospectively compared the incidence of pulmonary aspiration of gastric contents between patients endotracheally intubated in the prehospital (PH) setting and those intubated in the emergency department (ED). Tracheal aspirates were collected using a standard Leukens trap from all patients as soon as possible after endotracheal intubation. Tracheal aspirates were then tested for the presence of pepsin, a sensitive and specific marker of gastric contents, using a fibrinogen digestion technique. Over 8 months, 168 patients were enrolled. The pepsin assay was positive in 10 of 20 (50%) patients intubated in the PH group, as opposed to 33 of 148 (22%) of those intubated in the ED (chi2 P=.008; odds ratio, 3.5; 95% CI, 1.34-9.08). Patients endotracheally intubated in the PH setting are more likely to have aspirated gastric contents than those intubated in the ED.

An analysis of administrative data found that proximate clinical event ratios provided a systematic approach to identifying possible iatrogenic risk factors or complications

OBJECTIVE

A method to generate hypotheses about iatrogenic risk factors and complications from administrative data was developed and tested using hospitalization of the elderly for depression as a model.

STUDY DESIGN AND SETTING

Hospital claims were selected for 30,998 elderly inpatients admitted for the first time for depression. Common principal diagnoses and procedures in hospitalizations within 90 days of the index depression admission were tallied. For each of these proximate clinical events, the ratio of how many happened before the index admission to how many occurred afterward was calculated. Ratios diverging markedly from unity were identified to generate hypotheses about possible risk factors associated with depression and complications associated with its management.

RESULTS

Hospitalization for degenerative joint disease or back problems; abdominal pain or gastritis and duodenitis; coronary artery disease; or cerebrovascular disease was more common before an index depression admission than after it, as were coronary artery surgery, total knee replacement, and cholecystectomy. Admissions for fracture of the femoral neck--an established iatrogenic complication--were disproportionately likely after the index admission. So were admissions for aspiration pneumonia or acute respiratory failure.

CONCLUSION

Proximate clinical event ratios provide a systematic approach to screening administrative data to identify candidates for further evaluation as possible iatrogenic risk factors or complications.

A new pepsin assay to detect pulmonary aspiration of gastric contents among newly intubated patients

Aspiration of gastric contents by endotracheally intubated patients is associated with significant morbidity and mortality. Previous studies suggest that pepsin in tracheal aspirates may be a valuable marker of occult aspiration. We sought to show the sensitivity and specificity of a new, pepsin-specific assay in humans. A prospective, case-controlled study was conducted with subjects serving as their own controls. After planned endotracheal and nasogastric intubation for elective surgery, 20 participants had tracheal and gastric aspirates withdrawn. A blinded investigator tested samples for the presence of pepsin using the assay. Positive samples were then tested with pepstatin, a specific pepsin inhibitor, to ensure that positive results were due to pepsin. All tracheal aspirates tested negative and all gastric aspirates tested positive for pepsin. Pepstatin halted pepsin activity in all positive samples, ensuring that positive results were due to pepsin. A pepsin-specific assay is extremely reliable for detecting gastric contents in humans.

Gastric acid and particulate aspiration injury inhibits pulmonary bacterial clearance

OBJECTIVE

To establish a model of secondary bacterial pneumonia following gastric aspiration and to identify possible mechanisms involved in the suppressed antibacterial defenses following the initial pulmonary insult.

DESIGN

A controlled, in vivo laboratory study.

SETTING

Research laboratory of a health sciences university.

SUBJECTS

Ninety-five Long-Evans rats.

INTERVENTIONS

Animals were anesthetized for neck dissection and placement of a 14-gauge catheter in the trachea. Gastric aspirate (1.2 mL/kg of saline, pH 1.25, and 40 mg/mL sterile rat gastric particles) or an equal amount of normal saline (pH 5.3) was instilled intratracheally. One minute after this insult, animals received an intratracheal instillation of either 5.6 x 10 colony-forming units of Escherichia coli or an equal volume of normal saline. The animals remained in room air until kill at 4 hrs or 24 hrs after the intratracheal instillation. The lungs were homogenized for quantitative bacterial cultures. Bronchoalveolar lavage fluid was obtained for cell counts and measurements of albumin, tumor necrosis factor-alpha, interleukin-1 beta, cytokine-induced neutrophil chemoattractant-1, macrophage inflammatory protein-2, monocyte chemoattractant protein-1, and interleukin 10.

MEASUREMENTS AND MAIN RESULTS

Animals that received gastric aspirate (followed by normal saline or E. coli) had increased injury as assessed by significant reductions in oxygenation and elevations in bronchoalveolar lavage albumin. At 24 hrs, animals that received gastric aspirate inoculation followed by E. coli had significantly higher pulmonary bacterial counts compared with animals that received E. coli alone. Gastric aspiration injury followed by bacterial inoculation also resulted in acute, but transient, increases in tumor necrosis factor-alpha, interleukin-1 beta, cytokine-induced neutrophil chemoattractant-1, and macrophage inflammatory protein-2 and more sustained elevations of monocyte chemoattractant protein-1 and interleukin-10.

CONCLUSIONS

Lung injury increases and bacterial clearance decreases in this experimental model of E. coli pneumonia following gastric aspiration. Cytokine profiles suggest possible mechanisms for the impaired antibacterial host defense.

Aspiration pneumonitis in an overdose population: frequency, predictors, and outcomes

OBJECTIVE

To characterize the frequency of aspiration pneumonitis in an unselected population of overdose patients and, further, to identify factors that predispose to aspiration pneumonitis and the outcomes of patients with aspiration pneumonitis compared with those without.

DESIGN

Retrospective cohort study.

SETTING

Toxicology unit of a tertiary referral hospital.

PATIENTS

All poisoning admissions.

MEASUREMENTS AND MAIN RESULTS

A total of 71 of 4,562 poisoning admissions to the Hunter Area Toxicology Service between January 1997 and October 2002 had definite aspiration pneumonitis (1.6%; 95% confidence interval, 1.2-2.0). Older age, Glasgow Coma Score of <15, spontaneous emesis, seizures, delayed presentation to hospital, and ingestion of tricyclic antidepressants were associated with an increased risk of aspiration pneumonitis. Paracetamol poisoning and female sex were associated with a decreased risk of aspiration pneumonitis with univariate analysis. Ingestion of alcohol, benzodiazepines, antipsychotics, and administration of activated charcoal were not associated with aspiration pneumonitis. A logistic regression model for predicting aspiration pneumonitis contained seven predictors: age, sex, Glasgow Coma Score of <15 (odds ratio, 3.14; 95% confidence interval, 1.87-5.27), emesis (odds ratio, 4.17; 95% confidence interval, 2.44-7.13), seizure, tricyclic antidepressant ingestion, and time from ingestion to presentation (delay of >24 hrs [odds ratio, 4.42; 95% confidence interval, 2.42-8.10]). The mortality for patients with aspiration pneumonitis was 8.5% compared with 0.4% for those without (odds ratio, 23; 95% confidence interval, 9-60; p <.0001), and they had a significantly higher intensive care unit admission rate. The median length of stay of patients with aspiration pneumonitis was 126 hrs (interquartile range, 62-210 hrs) compared with 14.7 hrs (interquartile range, 7-23 hrs) in patients without (p <.0001).

CONCLUSIONS

Our study has shown a number of risk factors in overdose patients that are associated with aspiration pneumonitis that may allow the early identification of these patients for appropriate observation and management. Patients with aspiration pneumonitis have a significantly increased mortality and length of stay in the hospital.

Positive pressure mechanical ventilation

There have been numerous advances in the application of positive pressure mechanical ventilation in the last two decades. As knowledge of pulmonary physiology expands, the application of modes and parameters to maximize the efficacy and minimize the complications of ventilatory support continues to advance. As the use of noninvasive ventilation becomes more widespread, its usefulness in certain clinical entities such as COPD exacerbations and acute cardiogenic pulmonary edema will become more prominent. The role of specific modes and parameters of these devices likely will be further refined to maximize outcomes.

Central facilitation of the glottic closure reflex in humans

The sphincteric function of the larynx, essential to lower airway protection, is most efficiently achieved through strong reflex adduction by both vocal cords. We hypothesize that central facilitation is an essential component of a bilateral adductor reflex and that its disturbance could result in weakened sphincteric closure. Five patients during supraglottic laryngectomy underwent evoked response laryngeal electromyography under 0.5 and 1.0 minimal alveolar concentration (MAC) isoflurane anesthesia. The internal branch of the superior laryngeal nerve was stimulated through bipolar platinum-iridium electrodes, and recording electrodes were positioned in the ipsilateral and contralateral thyroarytenoid muscles. Consistent threshold responses were obtained ipsilaterally from 0.5 to 1.0 MAC anesthesia. However, the contralateral reflex responses approached 0% in successive trials as anesthetic levels approached 1.0 MAC. In human subjects, alteration of central facilitation by deepening anesthesia abolishes the crossed adductor reflex, predisposing to a weakened glottic closure response. A precise understanding of this effect may improve the prevention of aspiration in patients emerging from prolonged sedation or under heavy psychotropic control.

Adult toxicology in critical care: part I: general approach to the intoxicated patient

Intensivists are confronted with poisoned patients on a routine basis, with clinical scenarios ranging from known drug overdose or toxic exposure, illicit drug use, suicide attempt, or accidental exposure. In addition, drug toxicity can also manifest in hospitalized patients from inappropriate dosing and drug interactions. In this review article, we describe the epidemiology of poisoning in the United States, review physical examination findings and laboratory data that may aid the intensivist in recognizing a toxidrome (symptom complex of specific poisoning) or specific poisoning, and describe a rational and systematic approach to the poisoned patient. It is important to recognize that there is a paucity of evidence-based information on the management of poisoned patient. However, the most current recommendations by the American Academy of Clinical Toxicology and European Association of Poisons Centers and Clinical Toxicologists will be reviewed. Specific poisonings will be reviewed in the second section of these review articles.

Aspiration-related illnesses: definitions and diagnosis

BACKGROUND

Aspiration is a leading cause of morbidity and mortality. It is the most common cause of pneumonia and one of the most serious adverse effects of enteral nutrition support. It is important to use standardized terminology to define and discuss aspiration-related illnesses.

METHODS

Review of the medical literature and extraction of definitions and descriptions of aspiration-related illnesses.

RESULTS

Definitions, clinical features, diagnosis, and treatment of common aspiration-related illnesses are discussed.

CONCLUSIONS

Precisely defined terminology of aspiration-related illnesses adds consistency to this area of medicine and simplifies analysis and comparison of clinical studies.

Single-dose oral activated charcoal in the treatment of the self-poisoned patient: a prospective, randomized, controlled trial

Oral activated charcoal (OAC) is a universally accepted treatment of the overdose patient. Although the benefits of OAC have been suggested, there are no conclusive clinical data indicating that OAC affects outcome in overdose patients. This study was a prospective, randomized, controlled trial to determine the effects of OAC treatment in the self-poisoned adult patient. Adult patients presenting to the emergency department (ED) with a history of oral overdose were assigned to treatment with OAC (50 g) or supportive care only on an even-odd day protocol. Patients did not undergo gastric evacuation procedures in the ED. The outcome measures were clinical deterioration, length of stay in the ED or hospital, and complication rate. Over a 24-month period, 1479 patients were entered into the study. There were no significant differences in outcome parameters between the OAC treatment group and controls when comparing the length of intubation time, length of hospital stay, and the complication rates associated with the overdose. There was a higher incidence of vomiting and longer length of ED stay associated with OAC treatment. The results of this study indicated that oral drug overdose patients do not require gastric evacuation or charcoal administration. OAC provided no additional benefit to supportive care alone, was associated with a higher incidence of vomiting and a longer length of ED stay, and did not improve clinical outcome.

A study of mechanisms underlying amitriptyline-induced acute lung function impairment

In this study possible mechanisms underlying the vaso- and bronchoconstriction caused by the tricyclic antidepressant drug amitriptyline in isolated rat lungs were investigated. Some features here are similar to those apparent in adult respiratory distress syndrome and acute lung injury. Amitriptyline exposure (50 and 100 microM) caused a dose-related, pronounced, and rapid vaso- (50 microM, 30 min, p < 0.001 and 100 microM, 30 min, p < 0.001) and bronchoconstriction (50 microM, 30 min, p = 0.01 and 100 microM, 30 min, p < 0.001). The maximal noted decrease in perfusion flow was 28 +/- 2.9% at 25 min and 80 +/- 4.5% at 30 min for 50 and 100 microM amitriptyline, respectively. The maximal noted decrease in airway conductance was 29 +/- 4.7% at 25 min and 68 +/- 5.0% at 30 min. To investigate mechanisms thought to be involved in amitriptyline-induced lung function impairment, lungs were treated with several different substances including antiinflammatory agents, antioxidants, inhibitors of enzymes involved in the arachidonic acid cascade, physiological antagonists, and neurogenic antagonists. A significant reduction of amitriptyline-induced vasoconstriction was observed when lungs were treated with the protein kinase inhibitor staurosporine (3 microM, 30 min, p < 0.001), the NO-donor S-nitrosoglutathione (100 microM, 30 min, p < 0.001) and the combined endothelin A/endothelin B receptor antagonist PD 145065. This latter inhibitor caused a significant attenuation of late vasoconstriction (1 microM, 60 min, p = 0.03). The amitriptyline-induced bronchoconstriction was attenuated by the beta(2)-agonist salbutamol (1 microM, 30 min, p = 0.03) and the platelet-activating factor antagonist WEB2086 (10 microM, 30 min, p = 0.03). Staurosporine had an initial protective effect on bronchoconstriction (3 microM, 5 min, p = 0.003), while PD145065 significantly decreased bronchoconstriction 60 min after start of amitriptyline exposure (1 microM, 30 min, p = 0.003). This indicates that endothelin as well as platelet activating factor and protein kinase activation are important in mediating amitriptyline-induced lung function impairment in our experimental model and perhaps also in acute lung injury.

Drug-induced respiratory disorders: incidence, prevention and management

Various drugs are associated with adverse respiratory disorders (ARDs) ranging in severity from mild, moderate to severe and even fatal. Cardioselective and nonselective beta-blockers, calcium antagonists and dipyridamole can induce asthma. ACE inhibitors are mainly associated with cough. Amiodarone is related to a form of interstitial pneumonitis (IP) which can be fatal, tocainidine and flecainidine to a form of IP, and hydrochlorothiazide to a form of IP and pulmonary oedema. Antiasthmatic drugs can be associated with a paradoxical bronchospasm, while leukotriene antagonists are linked to the development of Churg-Strauss syndrome. Nonsteroidal anti-inflammatory drugs including aspirin (acetylsalicylic acid) may induce asthma. Gold is mainly related to IP, penicillamine to IP, systemic lupus erythematosus, bronchiolitis obliterans, and Goodpasture's syndrome. Acute respiratory reactions to nitrofurantoin include dyspnoea, cough, IP, and pleural effusion while IP and fibrosis are common in chronic reactions. Other antibacterials mainly evoke pneumonitis, pulmonary infiltrates and eosinophilia, and bronchiolitis obliterans. ARDs are similar for most categories of cytotoxic agents, with chronic pneumonitis and fibrosis being the most common. Noncardiogenic pulmonary oedema occurs as the most common respiratory complication in opioid agonist addiction. Psychotropic drugs such as phenothiazides, butyrophenones and tricyclic antidepressants can also induce pulmonary oedema. Oral contraceptives may produce asthma exacerbation, while long term use and/or high doses of postmenopausal hormone replacement therapy increase the risk of asthma. Bromocriptine is mainly associated with pleural effusion, while methysergide is usually associated with pleural effusion and fibrosis. Some anorectic agents have been linked to the development of primary pulmonary hypertension. The possibility of the occurrence of ARDs should be taken into account in each individual patient. Although in most cases the adverse effects are unpredictable, they can be reduced to a minimum or prevented if some drugs are avoided or stopped in time.

Drug-induced inflammatory responses to the lung

A number of drugs can induce lung toxicity. The lung manifestations can range from more acute responses such as an acute ARDS-like reaction, seen occasionally at overdosing of drugs to more insidious reactions, which can occur during conventional drug treatment. In many of these cases inflammation is an important component in the pathophysiology of drug induced lung toxicity. Very little is known about the mechanisms and initial events of drug-induced injury. In this review a couple of mechanistic aspects, related to drug induced lung injury, will be discussed such as reactive oxygen species (ROS)-generation, mediator release and disturbances in lung phospholipid turnover.

Amitriptyline-induced release of endothelin-1 in isolated perfused and ventilated rat lungs

We have previously shown that tricyclic antidepressants can induce vaso- and bronchoconstriction as well as oedema formation in isolated perfused lungs. This is an effect similar to that seen clinically in adult respiratory distress syndrome. In order to investigate whether endothelin can be a mediator of this reaction, isolated perfused rat lungs were exposed to 0.1 mM amitriptyline via the pulmonary circulation, perfusate was collected and endothelin-1 present in the perfusate and lavage fluids was determined by radioimmunoassay. A significant increase in perfusate concentration of endothelin-1 was noted, with the highest release seen within the first 10 min. of exposure. Histamine and thromboxane have also been proposed as mediators in induction of adult respiratory distress syndrome. However, no increased amounts of these mediators were detected in the perfusate. Experiments where lungs were exposed to exogenous endothelin-1(0.1-1 nmol), both via the perfusate and via intratracheal instillation were conducted. Similar effects as observed with amitriptyline (0.1 mM) on lung function and perfusion flow were detected. In conclusion, the detection of endothelin-1 release in our lung model proposes a role for endothelin-1 in amitriptyline-induced vaso- and bronchoconstriction and possibly in adult respiratory distress syndrome type reaction. Further studies with this model are interesting in order to elucidate mechanisms behind the complex issue of adult respiratory distress syndrome-induction.

Amitriptyline-induced loss of tight junction integrity in a human endothelial--smooth muscle cell bi-layer model

Tricyclic antidepressants can, when taken in overdose, cause serious pulmonary failure such as the adult respiratory distress syndrome (ARDS). In this study we have examined the effects of some tricyclic antidepressants (amitriptyline, imipramine, nortriptyline and desipramine) on the viability and morphology of human endothelial and smooth muscle cells derived from umbilical cord. Effects of amitriptyline on endothelial cell fluidity, as well as permeability changes to an endothelial-smooth muscle cell bi-layer, were also studied. The tricyclic antidepressants induced acute, sub-lethal toxicity in both cell types above 100 microM as assessed by the MTT reduction assay. Morphological changes were also observed at these concentrations. Such changes were, however, absent at 33 microM and below. Amitriptyline did, however, cause a concentration-dependent fall in the electrical resistance of an endothelial-smooth muscle cell bi-layer, with significant effects already evident at 33 microM. All of these observed effects were fairly rapid and appeared within 5-15 min of exposure. The rapidity of these permeabilisation effects suggests potential membrane perturbations, since tricyclic antidepressants are lipophilic molecules with affinity for cell membranes. However, fluorescence anisotropy measurements showed no significant difference in membrane fluidity between amitriptyline-treated and control endothelial cells. Collectively, these data point to specific mechanisms of action of amitriptyline, and probably also the other tricyclic antidepressants studied, on endothelial permeability, which is a hallmark of ARDS. The data suggest that increased endothelial permeability could be due to impaired tight junction function.

Incidence of aspiration pneumonia in intubated patients receiving activated charcoal

Several case reports and animal studies raise concerns over the risk of aspiration pneumonia when administering activated charcoal (AC) to intubated patients. Therefore, we sought to determine the incidence of aspiration pneumonia in intubated overdose patients who then received AC. We conducted a retrospective review from January 1994 to April 1997 of intubated patients who then received AC. Patients were transferred to, or primarily treated at, an 843-bed tertiary medical center with an annual emergency department volume of 100,000 patients. Objective evidence of infiltrate on chest radiograph during initial 48 h of hospitalization was used to determine the incidence of aspiration pneumonia. Patients with known preexisting pneumonia or with administration of AC before intubation were excluded. There were 64 patients identified. Fourteen were excluded for clinical aspiration before intubation, receiving activated charcoal before intubation, or abnormal immediate post-intubation chest radiographs. The remaining 50 patients, ages 1-64 years, 33% male, overdosing on a large variety of substances, required acute intubation and then received AC. Only two patients of these 50 (4%) with initial negative radiographs developed a new infiltrate after intubation and AC. Administration of AC to intubated overdose patients is associated with a low incidence of aspiration pneumonia.

Acute lung failure induced by tricyclic antidepressants

Overdosing of several drugs, such as tricyclic antidepressants, salicylates, and opiates, is known to induce effects like those seen in patients with adult respiratory distress syndrome. By exposing isolated perfused and ventilated rat lungs via the perfusate to six different tricyclic antidepressants (amitriptyline, nortriptyline, imipramine, desipramine, mianserine, and maprotiline), we investigated possible effects on ventilation (conductance and dynamic compliance), lung perfusion flow, and edema formation. The effects of these substances were pronounced and appeared within 15 min after exposure. Amitriptyline was studied in greater detail and caused a dose-related (0.01-1.0 mM) reduction in ventilation and perfusion flow. At the highest drug concentration pronounced lung edema was observed. Morphological studies were conducted with a transmission electron microscope. The microscopic preparations showed dose-related edema (amitriptyline 0.1 and 1.0 mM). The effects noted in our experimental studies are similar to those described in patients who have taken an overdose of tricyclic antidepressants. This emphasizes the possibility of a noncardiogenic edema component in these patients.

Dibenzepin overdose causing pulmonary edema

OBJECTIVE

To report a case of pulmonary edema due to dibenzepin overdose.

CASE SUMMARY

A 39-year-old woman was hospitalized 24 hours after she ingested eight tablets of dibenzepin hydrochloride delayed-release 240 mg/tablet (approximately 35 mg/kg body weight). On admission the patient was confused, and physical examination revealed sinus tachycardia (HR 130 beats/min). Forty-five hours after ingestion of the dibenzepin she developed pulmonary edema and was treated with furosemide, morphine, and mechanical ventilation through an endotracheal tube for 48 hours. Repeated echocardiography revealed left ventricular dysfunction that resolved as the medical condition of the patient improved. Appropriate studies excluded pneumonia, pneumonitis, adult respiratory distress syndrome, myocardial infarction, and pulmonary emboli as contributing factors to this patient's condition.

DISCUSSION

Tricyclic antidepressant overdose is known to cause cardiopulmonary complications, including pulmonary edema. To the best of our knowledge, this is the first reported case of pulmonary edema as a result of dibenzepin overdose. The most probable mechanism for this complication is depression of the left ventricular function.

CONCLUSIONS

As with other tricyclic antidepressants, dibenzepin toxicity may cause pulmonary edema. Close patient monitoring is essential for at least 48-72 hours after the overdose.

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.

Drug-induced pulmonary disease

Drug-induced disease of any system or organ can be associated with high morbidity and mortality, and it is tremendously costly to the health care of our country. More than 100 medications are known to affect the lungs adversely, including the airways in the form of cough and asthma, the interstitium with interstitial pneumonitis and noncardiac pulmonary edema, and the pleura with pleural effusions. Patients commonly do not even know what medications they are taking, do not bring them to the physician's office for identification, and usually do not relate over-the-counter medications with any problems they have. They assume that all nonprescription drugs are safe. Patients also believe that if they are taking prescription medications at their discretion, meaning on an as-needed basis, then these medications are also not important. This situation stresses just how imperative it is for the physician to take an accurate drug history in all patients seen with unexplained medical situations. Cardiovascular drugs that most commonly produce a pulmonary abnormality are amiodarone, the angiotensin-converting enzyme inhibitors, and beta-blockers. Pulmonary complications will develop in 6% of patients taking amiodarone and 15% taking angiotensin-converting enzyme inhibitors, with the former associated with interstitial pneumonitis that can be fatal and the latter associated with an irritating cough that is not associated with any pathologic or physiologic sequelae of consequence. The beta-blockers can aggravate obstructive lung disease in any patient taking them. Of the antiinflammatory agents, acetylsalicyclic acid can produce several different airway and parenchymal complications, including aggrevation of asthma in up to 5% of patients with asthma, a noncardiac pulmonary edema when levels exceed 40 mg/dl, and a pseudosepsis syndrome. More than 200 products contain aspirin. Low-dose methotrexate is proving to be a problem because granulomatous interstitial pneumonitis develops in 5% of those patients receiving it. This condition occurs most often in patients receiving the drug for rheumatoid arthritis, but it has been reported in a few patients receiving it for refractory asthma. Chemotherapeutic drug-induced lung disease is almost always associated with fever, thus mimicking opportunistic infection, which is the most common cause of pulmonary complications in the immunocompromised host. However, in 10% to 15% of patients, the pulmonary infiltrate is due to an adverse effect from a chemotherapeutic agent. This complication is frequently fatal even when recognized early.(ABSTRACT TRUNCATED AT 400 WORDS)

Accidental administration of activated charcoal into the lung: aspiration by proxy

We report a case of accidental activated charcoal instillation into the lung of a 30-year-old man being managed for a cyclic antidepressant overdose. The patient was treated with multidose activated charcoal, and between his first and second doses, he pulled his nasogastric tube out of position. The tube was reinserted past the endotracheal tube into the right mainstem bronchus, and a dose of activated charcoal with sorbitol was administered into the lung. He subsequently developed an adult respiratory distress syndrome but gradually improved after bronchoscopic removal of charcoal and supportive care. He was discharged 14 days later.

Pulmonary complications following tricyclic antidepressant overdose in an adolescent

OBJECTIVE

To report a case of pulmonary edema following a tricyclic antidepressant (TCA) overdose in an adolescent.

CASE SUMMARY

A 14-year-old girl with a history of prior suicide attempts ingested 54 50-mg desipramine hydrochloride tablets (45 mg/kg ingestion). The patient developed a cardiac dysrhythmia and hypotension, which were successfully treated. She subsequently developed pulmonary edema and a clinical picture suggestive of adult respiratory distress syndrome (ARDS). She was successfully managed with fluid restriction, tracheal intubation, application of positive end-expiratory pressure (PEEP), and vasopressors. The patient was discharged without any clinical sequelae.

DISCUSSION

Pulmonary complications secondary to TCA overdose have rarely been reported in children. We reviewed literature pertaining to the etiology, epidemiology, pathophysiology, and management of TCA-induced lung injury, as well as other case reports. We discuss the potential relationship between sequelae resulting from TCA ingestion (e.g., cardiac disturbances, hypotension, acidosis, gastric aspiration, pneumonia) and the development of ARDS and pulmonary edema, and relate this association to our patient.

CONCLUSIONS

Pulmonary edema and a clinical picture suggestive of ARDS was noted in an adolescent girl who ingested a large quantity of desipramine. Her lung injury may have been the result of a variety of factors including hypotension, metabolic acidosis, possible aspiration, or a direct action on the lung parenchyma by desipramine. We attribute her favorable clinical outcome to early intervention consisting of tracheal intubation, PEEP, fluid restriction, and vasopressor therapy.

Update in medical toxicology

This article examines some current issues in toxicologic care. First there is a review of the scope of pediatric poisonings and some aspects of initial management. Then there is a discussion of the decision-making process required to properly use gastric decontamination in the management of poisonings. Each of the common methods available--emesis, gastric lavage, activated charcoal, catharsis, and whole bowel irrigation--is discussed. Finally, several new and old antidotes are reviewed, namely naloxone, glucagon, bicarbonate, dimercaptosuccinic acid, digoxin-specific fab fragments, and flumazenil.