<prompt> Rise in end tidal CO2 during thyroid surgery can be due to all except:AnaphylaxisMalignant hypehermiaThyroid stormNeuroleptic malignant syndrome  <response>: A i.e. Anaphylaxis Thyroid storm, malignant hypehermia, neuroleptic malignant syndrome and pheochromocytoma are hypermetabolic states with a massive increase in CO2 production, characterized by hyperpyrexia, tachycardia striking alteration in consciousness and rise in ET CO2 end tidal CO2 on capnometeryQ. Anaphylaxis lt hypotension and shock results in hypoperfusion of lungs and deceased ET CO2Q. 