'Second gas effect' is exeed by which of the following gas when co-administered with halothane:

Concentration effect, second gas effect and diffusion hypoxia :- - Seen with inhalational agents used in high concentrations (like N2O) - Nitrous Oxide tends to increase sympathetic tone which counteracts with its weak direct depressant action on hea and circulation - Used as a carrier for adjuvant other anesthetics,as it decreases the conc. of other gases used along with it for same level of anesthesia - Diffusion hypoxia occurs due to rapid diffusion of nitrous oxide from blood to alveoli -N2O enter the cavity faster than N2 escapes, thereby increasing the volume and pressure in the cavity. Therefore it is contraindicated in obstruced bowel loops. Eg : gut volvulus