Download presentation
Presentation is loading. Please wait.
Published byArturo Woodin Modified over 9 years ago
1
Inhalational Poisoning Rama B. Rao, MD Bellevue Hospital Center/NYU Medical Center New York City Poison Control Center
2
Classes Simple asphyxiants Pulmonary irritants Particulates Mitochondrial toxins
3
Simple Asphyxiants Alveolar displacement O 2 Non-irritating No direct mitochondrial toxicity
4
Simple Asphyxiants Methane Carbon dioxide (CO 2 ) Helium Nitrogen Nitrous oxide
5
Lake Nyos: Carbon Dioxide
6
Nitrogen
7
Nitrous Oxide
8
Simple Asphyxiants: Symptoms Loss of consciousness –Minimal warning –Non-irritating Sustained exposure Hypoxia Cardiovascular collapse
9
Simple Asphyxiants: Treatment Safe rescue 100% oxygen Evaluation for other injuries Supportive care
11
Pulmonary Irritants Can behave in part like simple asphyxiants Mucosal irritation –Acid or base formation –Some free radical formation
12
Methyl Isocyanate
13
Pulmonary Irritants: Water Solubility Highly water soluble: –Ammonia –Sulfur dioxide –Hydrogen chloride –Chloramine Rapid onset
15
Pulmonary Irritants: Intermediate Solubility Chlorine –Exposure better tolerated initially –Increased duration exposure –Subsequent acid formation in upper and lower airways –Delayed effects Acute lung injury
16
Pulmonary Irritants: Low Solubility Include –Phosgene –Nitrogen dioxide Prolonged exposure Delayed –Pulmonary edema –Acute lung injury
18
Pulmonary Irritants: Treatment Removal from exposure Oxygen Nebulized bronchodilators For acid forming agents: –Nebulized sodium bicarbonate 1 part NaHCO 3 to 3 parts saline or water Primarily for symptomatic relief
19
Pulmonary Irritants: Treatment Supportive care Admission: –Severely symptomatic patients –Low and intermediate solubility exposures Arrange follow-up
20
Particulates and Aspirants Gas exchange impaired Supportive therapy –Intubation –ECMO –Bronchoaveolar lavage Can be fatal in children
21
Hydrocarbon Aspiration Surfactant disruption Higher severity: –Agents Low viscosity Surface tension High volatility –>30 mL exposures
22
Hydrocarbon Aspiration: Symptoms/Signs Cough Choking Dyspnea Rales Hypoxia May progress to ALI
23
Assess for evidence of aspiration –Clinical –Radiographic For asymptomatic patients without clinical evidence of aspiration –Observe 6 hours –Radiograph at 6 hours –Admit if signs or symptoms aspiration HC Aspiration: Management
24
Ware LB, N Engl J Med. 2000;342(18):1334-49.
25
MITOCHONDRIAL TOXINS
26
Mitochondrial Toxins Carbon monoxide Cyanide Hydrogen sulfide
27
Carbon Monoxide Incomplete combustion –Fires –Vehicular exhaust Methylene chloride Leading cause of poisoning deaths in the U.S
28
Toxicity CO Displacement O 2 –Alveoli –Hemoglobin binding sites (OCC) Impaired O 2 –Delivery –Utilization 100 Normal % Saturation Tissue pO 2 [mmHg] 20406080100 50% Anemia 50% COHb 75 50 25 0
30
CO Poisoning: Acute Signs and Symptoms Headache Myalgias Dyspnea Nausea, Vomiting Loss of Consciousness Chest pain Hypotension
31
CO Toxicity: Delayed Events Delayed neurological/ neuropsychiatric sequelae 2-40 days post-exposure Risks –Age –Loss of consciousness Signs and Symptoms Dementia Amnesia Confabulation Memory impairment Ataxia Chorea Cortical blindness Incontinence Paralysis Hypokinesia Parkinsonism Tremor
32
CO + HbCOHb (1. displaces O 2 from Hb 2. shifts O 2 dissociation curve) BloodMuscle CO + MbCOMb Mitochondria CO + cytochrome oxidase Inhibits electron transport (inhibits O 2 delivery to myocyte) ATP and O 2 utilization O 2 - and H 2 O 2 generation BP and CBF N 2 + O 2 2NO NOS Vasodilation (endothelium, platelets) Platelets CO binds to heme-containing platelet proteins CO-Platelets NO Affects 2 -integrins Xanthine dehydrogenase Xanthine oxidaseFree radicals Lipid peroxidation Proteases ONOO - NMDA activation PMNs adhere to vascular endothelium PMNS (inhibitors: tungsten, allopurinol) cGMP
33
Physiology: CO Binding Myocardium –CV impairment Hypotension Hemoglobin – Decreased OCC Functional Anemia Platelets and PMN –Nitric oxide Hypotension –Free radicals Lipid Peroxidation Mitochondria –Cytochrome oxidase Lipid Peroxidation –Impaired e transport Functional Hypoxia
34
Carbon Monoxide: Management 100% oxygen –Reduce half-life CO-Hb 6hr to 90 minutes Assess for pregnancy Note that pulse oximetry is inadequate –Oxygen saturation may appear artificially high Assess for end organ damage –VS, ECG, symptomatology, neurological examination
35
Carbon Monoxide Levels Venous sampling > 10% abnormal Levels correlate poorly with severity of exposurre
36
COHb levels (%)Symptoms 1-2Normal 5-10Smokers 10-20“Flu-like” symptoms 30-40Fatigue; Severe headache 40-50Confusion; loss of consciousness 60-70Coma Seizures CV collapse Death >70Rapidly fatal
37
Hyperbaric Oxygen Decrease COHb half life Displaces CO from tissues Improves oxygen carrying capacity Limits lipid peroxidation Improves dissolved oxygen
38
Hyperbaric Oxygen Variable outcomes in literature 2 : –Definition of DNS –Timing and duration of therapy –Co-exposures –Inability to define equivalent exposures –Patient variability
39
Hyperbaric Oxygen Weaver LK, et al: Hyperbaric oxygen for acute carbon monoxide poisoning. N Engl J Med 2002; 347:1057-67
41
Hyperbaric Oxygen: Indications Neurological damage Cardiovascular events Loss of Consciousness Persistent symptoms COHb > 25% ( some centers use >40%) COHb > 15% in pregnant woman Ideally within 6 hours of exposure
42
Cyanide Salts used in: –Electroplating –Mining extraction –Photography –Jewelry Nitroprusside Amygdalins Jim Jones, The People’s Temple
43
Cyanide Similar mechanism as CO –Mitochondrial toxin Acute exposure –Rapid onset –Lactic acidosis –Vomiting, seizures, coma
44
Cyanide Salts Alkaline liquid Gas –War –Combustion Zyklon B, WWII Auschwitz
45
Cyanide Antidote Kit
46
Cyanide Methemoglobin Cyanomethemoglobin Sodium Thiosulfate Cyt a-a 3 Mitochondria Sodium Thiocyanate Hemoglobin Nitrites Rhodanese
47
Treatment: Cyanide Antidote Kit Known or suspected cyanide poisoning Metabolic acidosis End organ damage
48
Nitrites for CN Caution if diagnosis is uncertain or if COHb is also suspected. Can omit nitrites if uncertain exposure. Caution
49
Hydroxocobalamin for CN
50
Hydroxocobalamin Kit Sodium Thiosulfate 8 gm IV Hydroxocobalamin 4 gm IV Under investigation Anaphylactoid reaction May interfere with some lab assays
51
Hydrogen Sulfide
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.