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October 28, 2003. Gases and Toxic Inhalation. 2. Outline. Inhalation exposureAsphyxiantsSimple asphyxiantsSystemic asphyxiantIrritant gases Smoke inhalationSemiconductors gases. October 28, 2003. Gases and Toxic Inhalation. 3. Inhalation exposure. The most common hazardous material exposureI
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1. October 28, 2003 Gases and Toxic Inhalation 1 Hazardous Material Medical CareGas and Toxic Inhalation ?.?. ????? ??????
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2. October 28, 2003 Gases and Toxic Inhalation 2 Outline Inhalation exposure
Asphyxiants
Simple asphyxiants
Systemic asphyxiant
Irritant gases
Smoke inhalation
Semiconductors gases
3. October 28, 2003 Gases and Toxic Inhalation 3 Inhalation exposure The most common hazardous material exposure
Involves large number of cases
Low potential for secondary contamination
Asphyxiant:
Simple asphyxiant
Systemic asphyxiants
4. October 28, 2003 Gases and Toxic Inhalation 4 Simple asphyxiants Displace oxygen from ambient air
Decrease FiO2
Inadequate oxygen for hemoglobin saturation
No pharmacological effects
Needs high ambient concentration to cause asphyxia
Situations:
Confined space
High ambient concentration -- compressed liquefied gas
5. October 28, 2003 Gases and Toxic Inhalation 5 Simple asphyxiants: Clinical manifestations Symptoms of hypoxia
CVS and CNS effects predominate
No hypercapnia
No dyspnea until severe hypoxia
Many cases pass out and die before developing obvious symptoms
6. October 28, 2003 Gases and Toxic Inhalation 6
7. October 28, 2003 Gases and Toxic Inhalation 7 Simple asphyxiants: specific agents Noble gases: Helium, argon, xenon
Short chain-aliphatic hydrocarbon gases: methane, ethane, propane, butane
Carbon dioxide
Nitrogen gases
8. October 28, 2003 Gases and Toxic Inhalation 8 Simple asphyxiants: treatment Decontamination: not needed
Removal from exposure
Respiratory support
Supplemental oxygen
Ventilation if needed
No role of hyperbaric oxygen
9. October 28, 2003 Gases and Toxic Inhalation 9 Systemic asphyxiants Carbon monoxide
Cyanide
Hydrogen sulfide
10. October 28, 2003 Gases and Toxic Inhalation 10 Carbon monoxide (CO) A leading cause of death from poisoning in western countries
Carbon monoxide: product of combustion of organic materials
Colorless, odorless and non-irritating gas
Major sources in Thailand:
Smoke inhalation
Exposure to methylene chloride (paint remover):
inhalation, skin, ingestion
conversion into carbon monoxide
11. October 28, 2003 Gases and Toxic Inhalation 11 Carbon monoxide poisoning CO is inhaled and absorbed at the rate proportional to respiration
Confined to blood and 15% to tissue predominately myoglobin
Elimination by gas exchange with half-life 4-6 hours at room air
CO 200-250 times affinity to hemoglobin when compared to oxygen
Shift oxyhemoglobin dissociation curve leftward
CO 60 times affinity to myoglobin when compared to oxygen
12. October 28, 2003 Gases and Toxic Inhalation 12
13. October 28, 2003 Gases and Toxic Inhalation 13 Acute carbon monoxide poisoning ‘Flu-like symptoms’
Headache and dizziness
Nausea, weakness, difficulty with concentration
Mild tachycardia and tachypnea
Syncope, seizures, altered mental status
Acute metabolic acidosis
Cherry red skin
14. October 28, 2003 Gases and Toxic Inhalation 14 Anginal chest pain in patients with predisposing coronary artery disease
Ischemic heart disease, cardiac arrhythmias and complications of IHD Acute carbon monoxide poisoning
15. October 28, 2003 Gases and Toxic Inhalation 15 Acute carbon monoxide poisoning: Diagnosis History: exposure history
Acute unconsciousness/ acute metabolic acidosis
Pulse oximetry may overestimate oxygen saturation; thus ABG should be used.
Confirmation: Carboxyhemoglobin
16. October 28, 2003 Gases and Toxic Inhalation 16 Normal (non-smoker): 5% or less/Normal smoker: up to 12%
Serious toxicity with level 25% or more
A comatose person may have a level close to zero.
Elevation of carboxyhemoglobin just confirms the poisoning.
In a patient with altered mental status, CT scan may show hypodensity change in globus pallidus and subcortical white matter as early as 6 hours after severe poisoning Acute carbon monoxide poisoning: Carboxyhemoglobin
17. October 28, 2003 Gases and Toxic Inhalation 17
18. October 28, 2003 Gases and Toxic Inhalation 18 Removal from exposure
100% oxygen therapy
Promotes tissue oxygenation
Enhance CO elimination
Half-life of 1-2 hours
Treat until patients become asymptomatic, CarboxyHb< 10% Acute carbon monoxide poisoning: Management
19. October 28, 2003 Gases and Toxic Inhalation 19 40% of cases
treated, completely recovered and appear fine.
Return of symptoms on day 20-40
Headache, memory and learning problems
Parkinsonism
Symptomatic treatment
50% recover and 50% permanent symptoms Acute carbon monoxide poisoning: long-term complications
20. October 28, 2003 Gases and Toxic Inhalation 20 Cyanide poisoning A powerful cellular poisoning
Inhalation exposure
Hydrogen cyanide gas
Combustion products
Other exposures:
Ingestion
Cyanide salts
Cyanogenic plants
Iatrogenic: infusion of degraded nitroprusside
21. October 28, 2003 Gases and Toxic Inhalation 21 Rapidly absorbed from respiratory tract
Distribute to RBC and tissues
Elimination by forming thiocyanate and excrete in urine
Half-life of 2.5 days in persons with normal renal function
Binds to Ferric ion in cytochrome a-a3:
enzyme in mitochondria
catalyzing electron transfer to oxygen Cyanide poisoning
22. October 28, 2003 Gases and Toxic Inhalation 22
23. October 28, 2003 Gases and Toxic Inhalation 23 Cyanide poisoning: Clinical manifestation Inhalation: Immediate onset
Low concentration (50 ppm or less): anxiety, restlessness, dyspnea, palpitation, headache
Higher concentration (100 ppm): death in 30 minute, tachycardia, tachypnea, syncope, seizures
High dose (250 ppm): Immediate onset: seizures, bradycardia or asystole, CVS collapse, respiratory depression, coma
24. October 28, 2003 Gases and Toxic Inhalation 24 Cyanide poisoning: Diagnosis History
Exposure: laboratories, jewelry, metal works
Clinical manifestation
Rapid onset and progression of manifestations
Arterialization of veins in fundoscopy
Severe type B lactic acidosis
Confirmation: erythrocyte cyanide level (< 50 mcg/L), retrospective
25. October 28, 2003 Gases and Toxic Inhalation 25 Removal from exposure
100% oxygen
Cyanide antidote may not be needed for inhalation victims who are asymptomatic or recovered before presentation
Cyanide antidote kit:
Amyl nitrite
Sodium nitrite
Sodium thiosulfate
Cyanide poisoning: treatment
26. October 28, 2003 Gases and Toxic Inhalation 26 Sodium nitrite Induces ‘methemoglobinemia’: Hb with Fe3+
Cyanide binds with Fe3+
Sodium nitrite 300 mg ( 10 ml of 3% NaNO2) IV over 5-10 minutes
Hypotension due to vasodilation
Amyl nitrite in cases of
Non-medical personal
No available IV line
27. October 28, 2003 Gases and Toxic Inhalation 27 Sodium thiosulfate Enhances cyanide elimination from the body
Sodium thiosulfate donates sulfur atom to rhodanase-catalyzed reactions to form thiosulfate
Thiosulfate excreted in urine
Hemodialysis in renal failure
Sodium thiosulfate 12.5 g (50 ml of 25% sodium thiosulfate)
28. October 28, 2003 Gases and Toxic Inhalation 28 Hydrogen sulfide Colorless gas with sweet odor
Intermediate water solubility
Product of bacterial decomposition of protein
Industries at risk: Liquid manure & fertilizer, fishing, brewers, tanning, natural gas & oil exploration, sewer construction
29. October 28, 2003 Gases and Toxic Inhalation 29 Inhalation
Irritation of upper and lower respiratory system
No bioaccumulation
Detoxification within 1 hour
Thiosulfate formation and renal excretion
Inhibits cytochrome oxidase a3
Inhibits aerobic metabolism Hydrogen sulfide poisoning
30. October 28, 2003 Gases and Toxic Inhalation 30
31. October 28, 2003 Gases and Toxic Inhalation 31 Odor threshold 1 ppm characteristic sweet, rotten egg odor
Olfactory fatigue within 10 minutes with 100 ppm; ‘loss of warning properties’
Low level: 10 ppm muscle fatigue on chronic exposure
50 ppm: Rapid onset of upper respiratory mucosal irritation: ocular pain, keratitis, cough, sore throat, corneal ulceration Hydrogen sulfide poisoning
32. October 28, 2003 Gases and Toxic Inhalation 32 250 ppm: systemic effects of cellular anoxia
Dyspnea, cough, tachypnea, chest pain
Headache, dizziness, lethargy, confusion, delirium, seizures, coma
Hypotension, tachycardia, myocardial ischemia and infarction, arrhythmias
1000 ppm: immediate death from respiratory depression and respiratory paralysis
Hydrogen sulfide poisoning
33. October 28, 2003 Gases and Toxic Inhalation 33 No specific laboratory from biological sample
History, clinical manifestations, metabolic acidosis and environmental sampling
Environmental sampling: ambient hydrogen sulfide level
Hydrogen sulfide poisoning
34. October 28, 2003 Gases and Toxic Inhalation 34 Removal from exposure
100% oxygen
Do not perform mouth to mouth resuscitation
Amyl nitrite and sodium nitrite for cases with manifestations of cellular hypoxia
Methemoglobin binds with hydrogen sulfide into sulfmethemoglobin
Hydrogen sulfide poisoning
35. October 28, 2003 Gases and Toxic Inhalation 35 Irritant gases Large variety of chemicals
Final common pathway: destruction of the integrity of respiratory mucosal barrier
36. October 28, 2003 Gases and Toxic Inhalation 36 Rapid onset of symptoms (seconds to minutes)
Signal to escape the exposure
Oral, nasal and pharyngeal pain
Mucosal edema, cough, stridor
Conjunctival injection, chemosis, skin irritation
Gases with good water solubility
Upper airway obstruction
Irritant gases: Clinical manifestationsShort exposure
37. October 28, 2003 Gases and Toxic Inhalation 37 Irritant gases: Clinical manifestationsProlonged exposure Gases without rapid onset of manifestation
Entry into lower respiratory tract
Tracheobronchitis, bronchiolitis, bronchospasm
Acute lung injury, non-cardiogenic pulmonary edema
Dyspnea, chest tightness, cough, frothy sputum, wheezing, crackles
CXR: alveolar infiltration
Arterial hypoxemia
38. October 28, 2003 Gases and Toxic Inhalation 38 Irritant gases: highly water-soluble gases Ammonia
Common industrial (plastic, fertilizer, refrigeration, explosives, cleaning agents) and household gases
Characteristic odor
Dissolution: NH4OH
Chloramine (NH2Cl)
Mixture of hypochlorite and ammonia
Dissolution: hypochlorous acid, ammonia, oxygen radicals
39. October 28, 2003 Gases and Toxic Inhalation 39 Hydrogen chloride
Industrial acid, combustion product of vinyl chloride
Dissolution: hydrochloric acid
Hydrogen fluoride
Glassware and semiconductor industry
Hydrofluoric acid
Upper and lower airway irritation, systemic hypocalcemia
Irritant gases: highly water-soluble gases
40. October 28, 2003 Gases and Toxic Inhalation 40 Sulfur dioxide
Smelting and oil refining
Warning properties: odor
Dissolution: sulfurous and sulfuric acids Irritant gases: highly water-soluble gases
41. October 28, 2003 Gases and Toxic Inhalation 41 Chlorine
Exposure: mixing hypochlorite with acid, aged hypochlorite tablet, compressed chlorine gas for water chlorination
Dissolution: Hypochlorous acid
Mild initial upper respiratory symptoms
Delayed symptoms of lower respiratory tract injury for hours
Irritant gases: intermediate water-soluble gases
42. October 28, 2003 Gases and Toxic Inhalation 42 Phosgene
Colorless gas, heavier than air
Musty odor
exposure
Combustion products of polyvinyl or isocyanate compounds
Chemical warfare Irritant gases: poorly water-soluble gases
43. October 28, 2003 Gases and Toxic Inhalation 43 Phosgene
Slowly dissolves into hydrochloric acid
Prolonged exposure
Upper and lower respiratory tract irritation
Delayed non-cardiogenic pulmonary edema up to 72 hours
44. October 28, 2003 Gases and Toxic Inhalation 44 Nitrogen dioxide
Reddish-brown color
Water insoluble
Heavier than air
Sources
Silos: grains
Combustion: nitrocellulose in films and bed mattress Irritant gases: poorly water-soluble gases
45. October 28, 2003 Gases and Toxic Inhalation 45 Nitrogen dioxide Mild upper airway irritation
Dissolution into nitric and nitrous acids in bronchiole, terminal bronchiole and alveoli
Acute non-cardiogenic pulmonary edema
Pulmonary inflammation and bronchiolitis obliterans 2-6 after the exposure
46. October 28, 2003 Gases and Toxic Inhalation 46 Nitrogen dioxide 1-3 ppm odor
15 ppm minimal irritation
50-150 ppm mild irritation
LD50 for 1 hour exposure = 175 ppm
Acute phase: Mucosal irritation (may last up to 2 weeks), methemoglobinemia
47. October 28, 2003 Gases and Toxic Inhalation 47 Delayed: 3-36 hours
Fever dyspnea rales hypoxemia cyanosis
Perihilar infiltration on CXR Nitrogen dioxide
48. October 28, 2003 Gases and Toxic Inhalation 48 Decontamination: Removal from gas exposure
Airway management & intubation
Oxygenation and PEEP
Bronchodilator for bronchospasm
Monitor ECG for patients with hydrocarbon exposure who receive bronchodilator Irritant gases: management
49. October 28, 2003 Gases and Toxic Inhalation 49 Patient with hydrogen fluoride inhalation
Nebulization of 2.5% calcium gluconate solution (1.5 mL of 10% calcium gluconate with 4.5 ml or NSS or water)
Prevent fluoride induced hypocalcemia
50. October 28, 2003 Gases and Toxic Inhalation 50 Smoke inhalation Another major mortality factor for patients with burns
Half of all fire-related deaths are due to smoke inhalation
Risk for smoke inhalation
Closed-space fire
Decreased mentation: overdose, alcohol intoxication, drug abuse, head injury
51. October 28, 2003 Gases and Toxic Inhalation 51 Combustion or pyrolysis: the rapid decomposition or oxidation of a substance by heat
Flame (light), heat, smoke
Components of smoke are unpredictable: composition of the fuels, oxygen availability, heat
Components of exposure from smoke inhalation
Particulate matters, fumes, aerosols, vapors
Toxic gases
Smoke inhalation
52. October 28, 2003 Gases and Toxic Inhalation 52 Heat: Thermal injury
Thermal injury occurs only at upper airway levels
Quick onset and rapid progression
Injury below vocal cord occur only in cases of steam inhalation
Smoke inhalation
53. October 28, 2003 Gases and Toxic Inhalation 53 Particulate matters:
Diameter less than 0.5 micrometer
Products of incomplete combustion of organic materials
Bronchospasm
Edema of mucosa from upper respiratory system down to terminal bronchiole
Onset of edema may be delayed up to 24 hours
Smoke inhalation
54. October 28, 2003 Gases and Toxic Inhalation 54 Toxic gases from smoke
Carbon monoxide: incomplete combustion of organic substance
Hydrogen cyanide: Combustion of nitrogen-containing organic substances: wool, silk, polyurethane, vinyl
Smoke inhalation
55. October 28, 2003 Gases and Toxic Inhalation 55 Examples of combustion products from common household materials
56. October 28, 2003 Gases and Toxic Inhalation 56 Clues for diagnosis of smoke inhalation
History of closed-space fire
Physical signs
facial burns, singed nasal hair, soot in the nose and throat, hoarseness, carbonaceous sputum, wheezing
Carboxyhemoglobin level as a document of exposure to incomplete combustion in a enclosed space
Chest x-ray may be normal at early stages Smoke inhalation
57. October 28, 2003 Gases and Toxic Inhalation 57 Treatment should start before the definite diagnosis is made
Early intubation may be needed to maintain airway: Indications for early intubation
Full-thickness burns of the face or perioral region
Circumferential neck burns
Progressive hoarseness
supraglottic edema or inflammation
100% humidified oxygen
Carboxyhemoglobin level Smoke inhalation
58. October 28, 2003 Gases and Toxic Inhalation 58 Empirical treatment for cyanide poisoning A patient with elevated carboxyhemoglobin
Suspected cyanide poisoning:history, comatose, lactic acidosis
Administration of sodium nitrite may worsen impaired oxygen transport
IV Sodium thiosulfate alone
59. October 28, 2003 Gases and Toxic Inhalation 59 Arsine A colorless, non-irritating gas
Heavier than air
Garlic-like odor
Semiconductor industry: production of gallium arsenide
Reaction of acids with arsenical compounds
60. October 28, 2003 Gases and Toxic Inhalation 60 Arsine depletes RBC glutathione
RBC cell membrane instability
Intravascular hemolysis
Absorbed into the body and is oxidized to trivalent arsenic compounds and cause chronic arsenic poisoning Arsine
61. October 28, 2003 Gases and Toxic Inhalation 61 Acute inhalation of level 250 ppm or more can cause death
Long term exposure of level 10-50 ppm can cause acute symptoms
Chronic low level exposure may cause arsenic poisoning
Arsine
62. October 28, 2003 Gases and Toxic Inhalation 62 Intravascular hemolysis
Headache, dizziness, malaise & weakness
Nausea and vomiting, abdominal pain
Dark-red ‘Cola color urine’ in 4-6 hours
Jaundice in 24-48
Acute (nephrotoxic) tubular necrosis: secondary to deposition of RBC breakdown products Arsine
63. October 28, 2003 Gases and Toxic Inhalation 63 Chronic arsenic poisoning
Malaise, nausea, headache
Painful peripheral neuropathy
Hepatitis
Bone marrow suppression
Mee’s line
Skin changes: hyper keratosis and hyper pigmentation, Bowen’s disease Arsine
64. October 28, 2003 Gases and Toxic Inhalation 64 History of exposure, cluster of cases
Abdominal pain
Intravascular hemolysis
Garlic-like odor
Arsine
65. October 28, 2003 Gases and Toxic Inhalation 65 Acute cases: Transient elevation of urine arsenic levels
Acute anemia with decreased haptoglobin
Negative Coomb’s test
Hemoglobinuria without hematuria
Hyperkalemia
Acute renal failure
Chronic cases: Elevation of urine arsenic level Arsine
66. October 28, 2003 Gases and Toxic Inhalation 66 Arsine : Treatment Decontamination: Removal from exposure
ABC: 100% oxygen
Supportive care:
Blood transfusion in case of severe anemia
Urine alkalinization and maintain urine flow
Hemodialysis
67. October 28, 2003 Gases and Toxic Inhalation 67 No enhancement of elimination
Chelation therapy:
No indications in acute cases
May be indicated for chronic exposure with persistent elevation of urine arsenic level
Follow up
Until stable hemolysis ceases and stable hematocrit
Subacute and long-term follow up for renal function and chronic arsenic poisoning
Asymptomatic exposed person should be observed for at least 6 hours
68. October 28, 2003 Gases and Toxic Inhalation 68 Thank you Do you have any question?