Hazmat Emergency Preparedness in Hong Kong: What are the Dangerous Goods in Kowloon?

Introduction

Hazmat emergency preparedness is critical, especially as Hong Kong prepares for major international events, such as the 2008 Olympic Equestrian Games. No published medical study has described the identities and quantities of dangerous goods (DG) in the Kowloon area and listed what antidotes are needed for these DG. This study describes what hazardous materials are most common in Kowloon to prioritise emergency preparedness and training.

Materials & methods

Design A descriptive, cross-sectional study. Setting The Hong Kong Special Administrative Region, specifically Kowloon. Sample The Hong Kong Fire Services Department (HKFSD) Dangerous Goods Database (DGD). Interventions Descriptive statistical analyses with Stata 9.2. Chief outcome Identifying and quantifying dangerous goods in the HKFSD DGD.

Results

Most DG do not have antidotes. The most common DG with recognised antidotes are carbon monoxide, methylene chloride, fluorine, fluorides, fluoroboric acid, cyanides, nitriles, methanol, nitrobenzene, nitrites, and nitrates. The most common categories of DG are substances giving off inflammable vapours, compressed gases, and corrosive and poisonous substances.

Conclusions

Hazmat emergency preparedness and training should emphasize these most common categories of DG. Disaster planning should ensure adequate antidotes for DG with recognised antidotes, i.e., oxygen for carbon monoxide and methylene chloride; calcium gluconate or calcium chloride for fluorine, fluorides, and fluoroboric acid; hydroxocobalamin for cyanides and nitriles; ethanol for methanol; and methylene blue for methaemoglobinaemia produced by nitrobenzene, nitrites, and nitrates. Supportive care is essential for patients exposed to hazardous materials because most dangerous goods do not have antidotes.

Metabolic effects of metaproterenol overdose: hypokalemia, hyperglycemia and hyperlactatemia

This case report of metaproterenol toxicity was associated with hypokalemia, hyperglycemia and hyperlactatemia. A similar triad has been reported in acute theophylline poisoning. Hypokalemia and hyperglycemia have been reported with other beta-agonists, but not metaproterenol. Patients presenting with the metabolic triad of hypokalemia, hyperglycemia, and hyperlactatemia should have theophylline and beta-agonist toxicity included in their differential diagnosis because the prognosis and therapy of these 2 intoxications is markedly different.

Continuous intravenous flumazenil infusion for benzodiazepine poisoning

This is the first US report of continuous iv flumazenil infusion for benzodiazepine poisoning. A MEDLINE search from 1966 to 1999 revealed no similar reports in the US literature. A 24-y-o woman ingested 50, 2 mg (=100 mg) flunitrazepam tablets in a suicide attempt. She presented 30 min after ingestion with a temperature of 36.5 C, blood pressure of 90/36 mmHg, pulse of 84/min, and shallow respirations of 8/min. Her Glasgow coma scale (GCS) was 8. Her ECG showed sinus rhythm at 80/min, a QRS axis of 30 with no terminal 40 msec deviation, and a QRS interval of 84 msec. She received 0.2 mg flumazenil iv and her GCS improved to 15. She was orogastrically lavaged and given 50 g of activated charcoal. Resedation to a GCS of 8 recurred twice, requiring additional 0.3 mg and 0.5 mg boluses of flumazenil iv, totaling 1.0 mg over 1 h. Then, a continuous flumazenil infusion was started at 1.0 mg/h, maintaining her GCS at 15. Fourteen h later, the continuous flumazenil infusion was terminated, resulting in resedation and clinical hypoventilation. Flumazenil infusion was restarted at 1.0 mg/h with resolution of sedation and hypoventilation. Thirty h after overdose flumazenil infusion was terminated without resedation or hypoventilation. Continuous iv flumazenil infusion is not US Food and Drug Administration approved, and further study is necessary in carefully selected patients to determine its safety and efficacy.

Continuous intravenous midazolam infusion for Centruroides exilicauda scorpion envenomation

STUDY OBJECTIVE

We sought to describe the effects of continuous intravenous midazolam infusion as therapy for severe bark scorpion (Centruroides exilicauda) envenomation.

METHODS

A retrospective chart review from July 1, 1993, through January 1, 1998, identified all patients treated at a university hospital with International Classification of Diseases, Ninth Revision, codes 989.5 (toxic effect of venom) or E905.2 (scorpion sting causing poisoning). By using standardized collection forms, data were extracted from the medical record of every patient who had a grade III or IV envenomation and was treated with a continuous intravenous midazolam infusion.

RESULTS

Our search identified 104 patients; 34 had grade III or IV envenomation. Of these, 33 were treated in the ICU with continuous intravenous midazolam infusion. Median patient age was 4 years (range, 1 to 68 years). Midazolam dosage was adjusted to induce a light sleep state to control agitation and involuntary motor activity. The median amount of midazolam resulting in the first recorded decrease in agitation and involuntary motor activity was 0.30 mg/kg (range, 0.03 to 1.76 mg/kg). This first evidence of clinical improvement was recorded as 1.00 hour (median), with a range of 0.00 to 3.75 hours. The initial midazolam infusion rate was 0.10 mg x kg(-1) x h(-1) (median), with a range of 0.01 to 0.31 mg x kg(-1) x h(-1). The maximal midazolam infusion rate was 0.30 mg x kg(-1) x h(-1) (median), with a range of 0.06 to 1.29 mg x kg(-1) x h(-1). The median time until the maximal midazolam infusion rate was 2.5 hours (range, 0.00 to 8.50 hours). The median duration of infusion was 9. 50 hours (range, 4.25 to 20.50 hours). The median length of stay in the ICU was 15.17 hours (range, 6.0 to 28.0 hours), and 85% of patients were discharged directly home. All patients had resolution of abnormal motor activity and agitation during their midazolam infusion. Transient hypoxemia without evidence of end-organ dysfunction was documented in 4 patients during midazolam therapy.

CONCLUSION

A continuous intravenous midazolam infusion can be a safe, effective, and readily available treatment option for patients with grade III or IV C exilicauda envenomation.

Recurrent and persistent coagulopathy following pit viper envenomation

BACKGROUND

Coagulation abnormalities following crotaline (pit viper) snakebite have traditionally been considered short-lived, but laboratory studies have rarely been reported beyond the first few days of treatment for envenomation. During the course of an antivenom clinical trial, we observed coagulation defects as late as 2 weeks following envenomation.

OBJECTIVES

To document and characterize the recurrence or persistence of coagulopathy among patients envenomed by pit vipers and treated with a Fab antivenom.

METHODS

Patients with moderate pit viper envenomation were enrolled in a multicenter, prospective clinical trial. A Fab-based antivenom preparation, antivenom polyvalent crotalid (ovine) Fab, was administered in all cases. Platelet count, fibrinogen level, presence of fibrin split products, prothrombin time, and partial thromboplastin time were determined before treatment and at standard intervals during the following 2 weeks.

RESULTS

Of 38 patients completing the study, 20 (53%) had recurrent, persistent, or late coagulopathy 2 to 14 days after envenomation. Thrombocytopenia occurred in patients with prior thrombocytopenia; hypofibrinogenemia occurred only in those with prior hypofibrinogenemia or positive fibrin split products. No patient experienced significant spontaneous bleeding. One patient with coagulopathy developed minor bleeding following minor surgery 12 days after envenomation.

CONCLUSIONS

Prolonged or recurrent coagulopathy may occur after envenomation by North American pit vipers. Patients treated with Fab-based antivenom may benefit from periodic rather than single-bolus dosing. Patients with coagulopathy should undergo close monitoring during the first 2 weeks after snakebite.

Envenomations

Envenomations are uncommon, challenging causes of critical care admissions. This article describes the diagnosis and treatment of envenomations that cause the most critical care admissions in the United States. Most are caused by the following animals: rattlesnakes, copperheads, cottonmouths, coral snakes, brown recluse spiders, and bark scorpions.

Intravascular hemolysis associated with North American crotalid envenomation

CASE REPORT

This is a case of severe intravascular hemolysis, without significant coagulopathy, following envenomation by a North American crotalid. A MEDLINE search from 1966-1997, and a review of older literature, revealed no similar cases. A 4-year-old girl was envenomated in her right foot by a 2.5 foot-long rattlesnake whose description matched that of the Hopi rattlesnake (Crotalus viridis nuntius). The snake was not captured. Her initial hematocrit was 45%. In spite of treatment with antivenin and improvement in her lower extremity pain and swelling, her hematocrit decreased to 20.4%. Laboratory tests and clinical exam showed a Coombs positive hemolytic anemia without significant signs of coagulopathy.

Squamous cells as predictors of bacterial contamination in urine samples

STUDY OBJECTIVE

To determine whether squamous cells in urine indicate bacterial contamination.

METHODS

We prospectively studied 105 consecutive women who presented to the emergency department with symptoms suggestive of a urinary tract infection. Two urine samples were collected from each woman, a midstream clean-catch (MSCC) sample and a catheterized (CATH) sample. Microscopic urinalyses to assess for squamous cells and urine cultures to assess for bacterial contamination were performed on all samples. Bacterial contamination was defined as growth of fewer than 10,000 colonies of a single species per milliliter or growth of three or more species of commensal bacteria (mixed flora) in a urine sample.

RESULTS

Squamous cells were found in 99 of 105 CATH samples (94%); however, no CATH samples had bacterial contamination. Squamous cells were found in 101 of 105 MSCC samples (96%); however, only 22 MSCC samples (21%) had bacterial contamination.

CONCLUSION

The presence of squamous cells in CATH urine samples obtained from women is not indicative of bacterial contamination. The presence of squamous cells in MSCC urine samples obtained from women also is not a good indicator, with an overall predictive value for bacterial contamination of 21%.

Spinal cord injury with a narrow spinal canal: utilizing Torg's ratio method of analyzing cervical spine radiographs

A 65-year-old inebriated man crashed his car and presented with spinal shock and neurogenic shock from a cervical spinal cord injury without cervical spine fracture or dislocation. The lateral cervical spine radiography was initially read as normal, except for degenerative disk disease; however, Torg's ratio method of analyzing cervical spinal canal sagittal width indicated the spinal canal was congenitally narrow. Magnetic resonance imaging confirmed this and showed bulging and herniation of multiple invertebral disks between C2 and C7. This case illustrates the value of using Torg's ratio method of analyzing lateral cervical spine radiographs. Although Torg's method has not been prospectively validated, it may be useful to identify patients at risk for cervical spinal cord injuries without fractures or dislocations. An abnormal Torg's ratio may be the only clue to the fact that the patient is at higher risk of spinal cord injury when the patient's history or examination is questionable because of head injury, drug intoxication, or therapeutic sedation and paralysis.

Exotic snakebite: envenomation by an African puff adder (Bitis arietans)

We report an envenomation by the African puff adder (Bitis arietans), an exotic snake in the United States. The patient developed swelling and ecchymoses in the affected extremity, and cutaneous necrosis of the envenomated fingertip. There was no significant coagulopathy. He received 20 vials of specific antivenin (Schlangengift-Immunserum Behring Zentralafrika, Behringwerke, Marburg, Germany) and debridement of devitalized finger tissue. The only permanent sequelae were cutaneous scarring and permanent loss of the fingernail on the envenomated finger. Exotic snakebite is a rare presenting problem in emergency departments. The initial approach to a patient envenomated by an exotic venomous snake is discussed. Use of antivenin and supportive care are emphasized.

Loxosceles arizonica bite associated with shock

Envenomation by the brown recluse spider (Loxosceles reclusa) is associated with shock, significant hemolysis, renal insufficiency, and disseminated intravascular coagulation (DIC). Shock has never been associated with envenomation by L arizonica, a related species indigenous to Arizona, southern California, and northwestern Mexico. We report the case of a 13-year-old girl, bitten by a specimen of L arizonica (the spider was identified by an entomologist), in whom shock and a typical cutaneous lesion developed. She did not experience renal insufficiency or disseminated intravascular coagulation. Infectious causes of shock were excluded. She recovered completely with supportive care.

Snakes and snakebite in Central America

This review treats the general biology, taxonomy, distribution and venom apparatus of the venomous snakes of Central America. Consideration has been given to the chemistry, pharmacology and immunology of the venom, and particular attention is dispensed to the clinical problem, including the treatment, of envenomations by these reptiles.

Cisapride poisoning

A MEDLINE search from 1966-1996 revealed no reports of cisapride poisoning. An 8-mo-old, 8.9 kg girl received 8 mL of cisapride (Propulsid Suspension, 1 mg/mL, Janssen Pharmaceutica, Titusville, NJ) rather than the usual dose of 0.8 mL, resulting in an inadvertent, 10-fold, iatrogenic, dosing error. She developed emesis, hyperactive bowel sounds, abnormal behavior, mild hyperthermia, tachycardia, hypertension, and thrombocytosis. This is the first published report of poisoning with cisapride.

Hemodialysis and hemoperfusion for treatment of valproic acid and gabapentin poisoning

A 31-y-old epileptic man developed coma and shock after suicidally ingesting large amounts of valproic acid and gabapentin. His peak valproic acid, level was 1306.9 micrograms/mL (therapeutic range = 30-100 micrograms/mL). His peak gabapentin level was 60.0 micrograms/mL (therapeutic range = 2.0-8.0 micrograms/mL). His hypotension was refractory to crystalloid and pressor infusions, but resolved during concurrent hemoperfusion and hemodialysis to enhance elimination of valproic acid. Concurrent hemoperfusion and hemodialysis, in series, produced a maximum valproic acid plasma clearance of 55.4 mL/min versus a maximum reported intrinsic valproic acid plasma clearance of 10.6 mL/min. concurrent hemoperfusion and hemodialysis, in series, should be considered in hemodynamically unstable patients with valproic acid poisoning whose clinical condition is worsening in spite of aggressive supportive care.

Gabapentin, valproic acid, and ethanol intoxication: elevated blood levels with mild clinical effects

CASE REPORT

A suicidal, epileptic patient ingested ethanol, valproic acid, and gabapentin, a new antiepileptic drug. He did well clinically despite elevated blood gabapentin, valproic acid, and ethanol.

CONCLUSIONS

Preliminary data from this case and one previous report indicate relatively mild clinical signs and symptoms with gabapentin poisoning.

Marijuana and hyperthermia

BACKGROUND

Animal and human laboratory studies suggest marijuana may cause hyperthermia. However, there are no clinical case reports of life-threatening hyperthermia associated with use of marijuana alone.

CASE REPORT

We report a patient who developed severe hyperthermia after smoking a marijuana cigarette and jogging on a warm day. He presented with delirium; hot, red, dry skin; and a rectal temperature of 41.7 degrees C. Historical and laboratory data indicated he had used cannabinoids and no other drugs. This is the first report of life-threatening hyperthermia temporally associated with use of marijuana alone.

Wound botulism

Wound botulism is a rare infectious and toxicologic complication of trauma and i.v. drug abuse. Only 39 cases have been reported in detail in the English literature. This case report describes a patient with wound botulism who presented to four medical facilities before receiving definitive diagnosis and treatment. Although his history and physical examination were consistent with wound botulism, diagnosis and therapy were delayed because this rare disease was not considered initially in the differential diagnosis. Wound botulism should be considered in trauma patients and i.v. drug abusers who present with cranial nerve palsies and descending paresis.

Wound botulism

All published cases of wound botulism were reviewed to describe the epidemiology, clinical manifestations, diagnosis, and treatment of this rare infection. The MEDLINE data base of English-language literature was searched from 1966 to 1992, using the keywords "wound botulism". Cases published during this period were identified, and the bibliographies of these articles were used to identify cases published before MEDLINE's search limit of 1966. Because of the limited number of published cases, all were reviewed. Data related to epidemiology, clinical manifestations, diagnosis and treatment were collected on each case. When possible, cross-references from case series or reviews were used to corroborate and supplement data for a given case. There were 40 cases identified as wound botulism. The case fatality rate was 10%. The 36 survivors had significant morbidity requiring prolonged medical care. Wound botulism is a rare life-threatening complication of trauma and i.v. drug abuse. The diagnosis should be considered in any patient with either of these risk factors who develop paresis of cranial nerves and a descending pattern of weakness. Treatment, including administration of antitoxin, should be initiated prior to definitive diagnosis by microbiologic laboratory tests.

Delayed toxic acetaminophen level after initial four hour nontoxic level

Antidotal therapy for acetaminophen poisoning is routinely based on a single acetaminophen level obtained four or more hours after ingestion. Some experts recommend additional acetaminophen levels if there are coingestants. This case report describes a 20-year-old woman who ingested acetaminophen 13 g, propoxyphene napsylate 2 g and naproxen sodium 3.75 g. A 4.5 h acetaminophen level was 83.5 mg/L (nontoxic). A 6.75 h acetaminophen level was 124.6 mg/L (toxic). The patient was treated with N-acetylcysteine and recovered without sequelae. This is the first published report of a delayed toxic acetaminophen level occurring after an initial nontoxic level. Although rare, the possibility of a delayed peak acetaminophen level merits consideration, particularly with coingestions that delay gastric emptying.

Amelioration of nifedipine poisoning associated with glucagon therapy

Glucagon relieves calcium channel blocker-induced hypotension in animal studies. There are no published case reports of glucagon relieving hypotension in patients with calcium channel blocker poisoning. We describe a patient who developed hypotension after ingestion of 900 mg nifedipine. Therapy with IV lactated Ringer's solution and calcium chloride alone did not relieve his hypotension. However, hypotension rapidly resolved after the addition of IV glucagon therapy. This is the first case report of glucagon therapy at least temporally associated with relief of hypotension in a patient with calcium channel blocker poisoning. More research is needed to determine the appropriate role for glucagon in treating patients with calcium channel blocker poisoning.

Iodoquinol associated seizures and radiopacity

This case report describes seizures and encephalopathy in a nine year-old boy treated with iodoquinol for amebiasis. The toxicity of iodoquinol and other 8-hydroxyquinolines is discussed. The radiopacity of this medication, used worldwide for the treatment of diarrheal illnesses and dermatitis, may be diagnostically useful.

Urine sampling in ambulatory women: midstream clean-catch versus catheterization

We conducted a study to determine if there were any significant differences in urinalyses or urine cultures obtained by midstream clean-catch (MSCC) urine sampling in comparison with in-and-out catheterization (CATH). One hundred five women with symptoms suggestive of a urinary tract infection were studied prospectively. Each woman had a MSCC urine sample obtained initially, followed by a CATH sample. The MSCC and CATH urine samples were analyzed and compared for urine culture, leukocyte esterase, nitrites, microscopic bacteriuria, and pyuria. Of the 105 patients, 42 (40%) had a culture-proven urinary tract infection. The concordance rates between MSCC and CATH urine cultures, nitrites, leukocyte esterase, significant microscopic bacteriuria, and pyuria were 96%, 94%, 93%, 90%, and 90%, respectively. There were no statistically significant differences between MSCC and CATH sensitivities, specificities, or positive or negative predictive values for any urinalysis variable (leukocyte esterase, nitrites, significant microscopic bacteriuria, or pyuria). We conclude that if proper MSCC technique is used, the differences between MSCC and CATH urinalyses or urine cultures do not appear to be significant in the majority of ambulatory women without active vaginal bleeding who present with symptoms suggestive of a urinary tract infection.