Carbon dioxide asphyxiation

Euthanasia methodology affects the ease by which metastases can be detected and quantified. Three methods have been used by my laboratory—carbon dioxide asphyxiation, cervical dislocation and overdose using anesthetics. Alt methods for euthanizing an-imeds must be approved beforehand by the Institutional Animal Care and Use Committees (lACUC). Guidelines for euthanasia are evolving hence, regular consultation with veterinarians concerning procedures is advised. 

Butylenes are not toxic. The effect of long-term exposure is not known, hence, they should be handled with care. Reference 96 Hsts air and water pollution factors and biological effects. They are volatile and asphyxiants. Care should be taken to avoid spills because they are extremely flammable. Physical handling requires adequate ventilation to prevent high concentrations of butylenes in the air. Explosive limits in air are 1.6 to 9.7% of butylenes. Their flash points range from —80 to —73° C. Their autoignition is around 324 to 465°C (Table 2). Water and carbon dioxide extinguishers can be used in case of fire. 

Products of Combustion Heat, hght, smoke, and asphyxiating and toxic gases are produced by fire. In a hot, well-ventilated fire, combustion is usually nearly complete. Nearly all the carbon is converted to carbon dioxide, all the hydrogen to steam, and oxides of various other elements such as sulfur and nitrogen are produced. 

Carbon dioxide gas ean aet as an asphyxiant due to displaeement of air, resulting in oxygen defieieney (page 262). Sourees inelude ... 

Carbon dioxide and certain halon compounds have a specialized application for fires in electrical equipment where a non-conducting medium is important. All are toxic to a degree, and operate either by smothering the fire or by a chemical reaction which inhibits combustion. Gas extinguishers must not be used in a confined space because of the toxic risk or the risk of asphyxiation. 

Asphyxiants interfere with the body s oxygen uptake mechanisms. Air normally contains 21% oxygen. Oxygen deficiency in inhaled air, e.g. due to the presence of nitrogen, argon, or carbon dioxide in a confined space, depending on the concentration and duration, may affect the body and ultimately cause death from simple anoxia (Table 4.7). 

Carbon dioxide gas can act as an asphyxiant due. to displacement of air, resulting in oxygen deficiency (page 43). Sources include ... 

Note that C02 acts as neither a simple asphyxiant (like N2) nor a chemical asphyxiant (like CO). The normal concentration of C02 in air is approximately 300 ppm (0.03 vol %). Table 23-19 (Air Products, Carbon Dioxide, Safetygram 18, 1998) illustrates that exposure to air diluted by 5 vol % C02 (yielding an oxygen concentration of 21 x 0.95, or approximately 20 vol %) prompts physiological effects that are more severe than those inferred from Table 23-18 for dilution by the same amount of nitrogen. 

Carbon dioxide gas is an asphyxiant, a potent respiratory stimulant, and both a stimulant and depressant of the central nervous system. Fatalities have occurred after people have entered enclosures where air has been largely displaced by CO2. Therefore, fixed, automatic CO2 systems require a time delay pre-evacuation alarm period (often 30 seconds), warning signs, and an alarm signal incorporated into the system design to allow sufficient time for personnel evacuation prior to CO2 release. Verification of the oxygen level must be made prior to reentry. 

Carbon dioxide (CO2) is a colorless and odorless gas. It is an asphyxiant-causing agent. A concentration of 10% can cause unconsciousness and death from oxygen deficiency. The gas can be released from industrial studies [39], automobile exhaust, environmental tobacco smoke (ETS), and inadequately vented fuel heating systems. It is heavy and accumulates at low levels in depressions and along the floor. 

Toxicology. Carbon dioxide usually is considered a simple asphyxiant, although it also is... 

Asphyxiant A gas or vapor which, when inhaled, may lead to asphyxia. Examples of asphyxiating materials are carbon dioxide and carbon monoxide. 

These cattle were asphyxi- ated by an enormous bubble of carbon dioxide that welled up from the depths of Lake Nyos,... 

The liquid can be exploded by a detonator, though not by mechanical shock [1]. Use of propylene oxide as a biological sterilant is hazardous because of ready formation of explosive mixtures with air (2.8—37%). Commercially available mixtures with carbon dioxide, though non-explosive, may be asphyxiant and vesicant [1], Such mixtures may be ineffective, but neat propylene oxide vapour may be used safely, provided that it is removed by evacuation using a water-jet pump [2]. The main factors involved in the use and safe handling on a laboratory scale have been discussed [3]. The energy of decomposition (in range 340—500°C) has been measured as 1.114 kJ/g [4]. 

IACUC approved protocols. These are recommended by the American Veterinary Medical Association and the protocols are regularly reviewed and revised (http //www.avma.org/issues/ animal welfare/euthanasia.pdf). Currently, a commonly used and IACUC approved euthanasia method is carbon dioxide gas asphyxiation. 

When contemplating this approach, the constmction materials must be carefully considered to determine whether low temperatures will cause them to become brittle or stressed. Furthermore, care should be taken to avoid asphyxiation when using large quantities of carbon dioxide, nitrogen, etc., especially in a confined space and inside buildings (Lees, 1980). 

Asphyxiates paralyze the respiratory center and weaken the body. They disturb the maintenance of an adequate oxygen supply to different systems in the body. The most common asphyxiates are carbon dioxide, carbon monoxide, cyanides, helium, nitrogen, and nitrous oxide. 

Handle in accordance with standard procedures for handling metal cylinders containing liquefied or compressed gases. Carbon dioxide is an asphyxiant and inhalation in large quantities is hazardous. It should therefore be handled in a well-ventilated environment equipped with suitable safety devices for monitoring vapor concentration. 

Carbon dioxide is a simple asphyxiant that is, it causes toxicity by displacing oxygen from the breathing atmosphere primarily in enclosed spaces and results in hypoxia. It has been postulated that the cause of death in breathing high concentration of carbon dioxide is due to carbon dioxide poisoning and not hypoxia based on a study performed in dogs. 

Following exposure to asphyxiants, cardiovascular effects like tachycardia, arrhythmias, and ischemia are noted. Carbon dioxide exerts a direct toxic effect to the heart, resulting in diminished contractile force. It is also a vasodilator and the most potent cerebrovascular dilator known. Respiratory effects like hyperventilation, cyanosis, and pulmonary... 

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