D i.e. Halothane Halothane (2- bromo - 2- chloro - 1, 1, 1 trifluoroethane) is a potent, non inflammable, non toxic (relatively), colourless liquid with relatively non pungent (pleasant) vapour. It is decomposed by light and stabilised by 0.01% thymolQ, but is stable when stored in amber coloured bottles. Although it is decomposed by soda lime, it may be used safely with this mixture. The vapour is absorbed by rubberQ (rubber/gas paition cofficient is 120). It corrodes metals in vaporizers and breathing systemsQ. In the presence of moisture, it corrodes aluminium, tin, lead, magnesium and alloysQ. It should be stored in a closed container away from light and heat. It is soluble in rubber, and plasticsQ commonly found in ansethetic circuits. This has obvious implications for patients with halothane sensitivity, or who are at risk for malignant hypehermia, in whom anesthetic free circuit should be used. Halothane, Ketamine & AtropineQ are bronchodialators. These agents decrease airway resistance and increase anatomical dead space. Aspiration, regurgitation & intubation leads to reflex bronchospasm.