<prompt> Rise in end-tidal CO2 during thyroid surgery can be due to all exceptAnaphylaxisMalignant hyperthermiaThyroid stormNeuroleptic malignant syndrome  <response>: Anaphylaxis is generally associated with hypotension, shock, and hypoperfusion of lungs and results in decreased End Tidal CO2 measurements.Thyroid storm hypermetabolic state, malignant hyperthermia and neuroleptic malignant syndrome can cause rise in ETCO2. 