Hom MSc Counselling and Psychotherapy Associate Professor Forensic Medicine and Toxicology Sarada Krishna Homoeopathic Medical College Kulasekharam Irritants gases injure the air passages or lungs or both and produce inflammatory changes Smoke tear gases amm ID: 998360
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1. ASPHYXIANTSDr. V.SIJU; M.D (Hom); M.Sc (Counselling and Psychotherapy)Associate Professor; Forensic Medicine and Toxicology; Sarada Krishna Homoeopathic Medical College Kulasekharam
2. Irritants : gases injure the air passages or lungs or both and produce inflammatory changes. Smoke, tear gases, ammonia, phosgene etc.Chemical asphyxiants: these are gases which by combining with hemoglobin, or by acting on some tissue constituent prevent oxygen from reaching tissue or the tissues from using it. CO, hydrogen sulphide, arsine, carbon disulphide, and cyanide.Simple asphyxiants: inert gases, which when breathed in high concentration act mechanically by excluding o2. co2, methane, helium, nitrogen.
3. Volatile drugs: these are gases with little or no irritant effect upon the air-passages, which act after absorption into the blood, either as an anesthetic, or as agents toxic to the liver, kidneys or other organs including the nervous system. Aliphatic hydrocarbons, halogenated hydrocarbons and aromatic hydrocarbons.Systemic poisons: insecticides, arsine, stibine.
4. CARBON MONOXIDE POISONIG:CO is a colorless, tasteless, odorless, nonirritant gasProduced due to incomplete combustion of carbon.Insoluble in water.Rapidly absorbed across alveolar-capillary membraneAmount of CO absorbed is dependent on:Level of CO in the environmentMinute ventilationDuration of exposureHemoglobin’s affinity for CO is 200 to 250 times its affinity for oxygen
5. Tobacco smoke is the largest source of inhaled COindependent of nicotine levelsHbCO levels chronically elevated0.5% for nonsmokers 3% to 8% for “heavy smokers”Sources: Burning fuels such as: wood, oil, natural gas, gasoline, kerosene, propane, coal and dieselCommon sources of human exposure include:Smoke inhalation from firesAutomobile exhaustFaulty or poorly vented charcoal, kerosene or gas stoves To a lesser extent, cigarette smoke and methylene chloride (industrial uses)
6. Mode of action:CO+Hb=COHb.It thus reduces the o2 content of the blood, and hence that of the tissues. It acts as a chemical asphyxiants and produce death due to anaemic anoxia. CO is a potent cellular toxin. It effectively and firmly binds to haemoglobin and myoglobin. It inhibits the electron transport by blocking cytochrome A3 oxidase and cytochrome p-450, and therefore intracellular respiration.
7. Enters the body through the lungs and is delivered to the bloodRed blood cells pick up CO instead of oxygenHemoglobin likes CO 250 times more than oxygenCO prevents the oxygen that is present from being readily released to and used properly by tissues
8. Normally , after somatic death, the cells near the capillaries continue to function, extract O2 from oxyhaemoglobin and cause blue staining. In CO poisoning, the cells cannot break the COHb compound. So the blood under the skin and in the tissues will be cherry- red due to oxyhaemoglobin.
9. - 100 -- 90 -- 80 -- 70 -- 60 -- 50 -- 40 -- 30 -- 20 -- 10 -- 0 -No effectNo major effect except for Shortness of Breath on Extreme Physical ActivityExtreme Shortness of Breath during Moderate Exertion, Minor HeadachePronounced Headache, Fatigue, Irritability, Impaired JudgmentHeadache, Disorientation, Fainting, CollapseUnconsciousness, Respiratory Failure, Death in Long ExposuresImmediate Death Carbon Monoxide (Symptoms)
10. Warning Symptoms of Carbon Monoxide PoisoningSense of pressure in the headRoaring/ringing sensation of the earsPatient is confused and unable to think clearlyDrunk appearanceOften vomitingIncontinentConvulsionsBounding Pulse
11. Cherry red lipsDilated pupilsComaNote: You should consider Carbon Monoxide poisoning whenever confronted with a group of people with different symptoms who are sharing accommodations.
12. Treatment for Carbon Monoxide PoisoningRemove the patient from the exposure siteProvide patient with 100% oxygen or expose him to fresh airMonitor the patient for further respiratory distressEvacuate patient to trained medical professionals
13. Postmortem appearances: a cherry red coloration of the skin, mucus membranes, conjunctivae, nail-beds, areas of hypostasis, blood, tissues and internal organs. The blood is fluid, hyperemia is general and serous effusions are common.Blistering of the skin of dependent areas.Congestion of the lungs with pink fluid blood.Punctiform and ring-shaped haemorrhages in the white matter of the brain with widespread oedema are common.
14. MLI: Suicide: rare.Accident: common.Homicide: uncommon.
15. CARBON DIOXIDE:It is a heavy, colorless gas with a faintly sweet odour. Atmospheric air contains 0.033% CO2, 21% O2, 70-80% nitrogen. CO2 in excess seen in old wells, ship holds, cellars.It act as a simple asphyxiants by preventing the tissue from obtaining O2.Artificial respiration and O2 should be given.There is marked cyanosis, congestions, suffusion of the eyes, dilation of pupils and petechial haemorrhages.Poisoning is usually accidental.
16. HYDROGEN SULPHIDE: (H2S).It colourless, heavy, flammable gas with a smell of rotten eggs. It is formed during decomposition of organic substances containing sulphur. H2S in combination with CO2 and methane formed in sewers ,is known as Sewer gas.Remove the patient from the exposure siteProvide patient with 100% oxygen or expose him to fresh airRotten egg odour, signs of asphyxia, the colour of the blood and viscera and bronchial secretions is greenish-purple.
17. WAR GASES: Any chemicals which is used to produce destruction or damage mostly in times of war.Vesicant or blistering gases – it causes irritation of the eyes, nose, throat and respiratory passages.It passes through the clothes into the skin and produces intense itching, redness, vesication, and ulceration especially of the moist areas. Wash the affected parts thoroughly. Eye wash with sodium bicarbonate solution.
18. Asphyxiants or lung irritants: Chlorine and phosgene.Their action is mainly on pulmonary alveoli. When, inhaled they cause watering of the eyes, coughing, dyspnoea, tightness of chest, headache, vomiting, restlessness, stertorous breathing, cyanosis and collapse.Death occurs in 24-48 hrs due to acute pulmonary oedema.Eye wash with boric acid.O2 .
19. Lachrymators: the vapours cause intense irritation of eyes with a copious flow of tears, spasm of eyelids and temporary blindness.Removed to the fresh air.Eyes washed with warm normal saline.Nasal irritants: Paralysants: Nerve gases:
20. HYDROCYNIC ACID It is a vegetable acid found in nature in many fruits and leaves, such as almond, apple, cherry, plum, pear, bamboo shoots and in certain oil seeds and beans, where it exists in the form of a glucoside amygdalin, which is harmless, but usually co-exists with the enzyme emulsin, which hydrolyses it and liberates hydrocyanic acid.
21. It is a colourless, transparent, volatile liquid with an odour like bitter almonds and is rapidly decomposed by exposure to light. Cyanides are white powders and are in common use in many trades, in metallurgy, photography, electroplating etc.
22. Action: Cyanide inhibits the action of cytochrome oxidase, carbonic anhydrase. It blocks the final step of oxidative phosphorylation and prevents the formation of ATP and its use as energy source. Cyanide acts by reducing the oxygen carrying capacity of the blood, and by combining with the ferric iron atom of intracellular cytochrome oxidase, preventing the uptake of oxygen for cellular respiration.
23. There is an interference with the intracellular oxidative processes in the tissues and it kills by creating histotoxic or cytotoxic anoxia, although the blood may contain a normal oxygen content.
24. Absorption and Excretion: Cyanide gas is absorbed rapidly from the respiratory system, and the acid and cyanide salts from the stomach. The greater part is converted by an enzyme rhodanase present in liver and kidney into thiocyanate. A small amount is excreated unchanged in the breath. It is mainly excreated in urine.
25. Signs and Symptoms: Most rapid of all poisons. When inhaled as a gas, its action is instantaneous. With small doses , the person first experiences headache, confusion, giddiness, nausea and loss of muscular power. Massive doses may produce sudden loss of consciousness and prompt death from respiratory arrest. All symptoms ultimately reflect cellular hypoxia.
26. C.N.S: Headache, Vertigo, faintness, perspiration, anxiety, excitement, confusion, drowsiness, prostration, opisthotonous and trismus, cramps, twitchings etc.G.I.T: Bitter, acid, burning taste, salivation, nausea.R.S: Odour of bitter almonds in breath. C.V.S: initially hypertention with reflex bradycardia, sinus arrhythmia.Skin: Perspiration, bullae.Eyes: Glassy and prominent, pupils dilated.Renal: Acidosis.
27. Inhalation of vapor produces a sense of constriction about the throat and chest, dizziness, vertigo, insensibility, and death from respiratory failure. Inhalation of air containing one part in 2000 of cyanide is fatal almost immedieately, 1 part in 1000 within few minutes, and 1 part in 5000 within few hours.
28. Fatal Dose: 50-60 mg of pure acid; 200-300mg of Sodium or Potassium cyanide. A concentration of 1:500 in air causes immediate death.Fatal Period: 2-10 minutes. Sometimes immediate.
29. Treatment: Treatment should be started immediately.The principle of the treatment is to reserve the cyanide-cytochrome combination. This is achieved by converting Hb to methHb by giving nitrites. MethHb has a higher binding affinity for cyanide than the cytochrome oxidase complex , and removes cyanide from cytochrome oxidase.
30. Cyanides combine with methHb and form non-toxic cynamethHb which in the presence of rhodanase and sulphate donors, such as thiosulphate, converts cyanide to thiocyanate which is excreated in the urine. Cyanide is directly converted to thiocyanate by the complexing of cyanide with thiosulphate under the influence of the enzyme rhodanase.
31. Cyanide is also converted to cyanocobalamin by complexing with hydroxocobalamin.Cytochrome oxides+NaCN -> Cytochrome oxidase cyanide.Sodium nitrite+Hb -> metHbMetHb+NaCN->cyanmetHb.
32. Break 0.2ml. Ampoule of amyl nitrite in a handkerchief and hold over the patient’s nose for 15-30 seconds of every minute. 0.3 g. of Sodium nitrite in 10ml. Of sterile water is given i.v. slowly, over a period of five minutes. through the same needle infuse 25 g. of sodium thiosulphate in 15% solution i.v. over a period of ten minutes.Both sodium nitrite and sodium thiosulphate can be repeated at half the initial dose at the end of one hour if symptoms persist.Hydroxocobalamin 4g.i.v. as infusion is given.
33. 6. Keep the airway clear.7. In poisoning by inhalation, remove the patient at once to fresh air and start artificial respiration and oxygen.Postmortem Appearances: The eyes may be bright, glistening and prominent with dilated pupils.The jaws are firmly closed and there is froth at the mouth.
34. The odour of hydrocyanic acid may be noticed on opening the body.All the vessels of the body including the veins contain oxygenated blood. Bloodstained froth may be found in the trachea and bronchi.There is congestion of viscera and oedema of the lungs.
35. MLI:Suicide. Suicide pills.Accident- rare.Homicide – rare.
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