5 yr old child going to sitting craniotomy while positioning in O.T. developed End Tidal CO2 0mm Hg P02 80 mm Hg implies

C i.e. Venous Air embolism A patient undergoing lapro/thoraco-scopyQ or procedure (eg craniotomy) in sitting, head upQ, park-bench, knee-chest positions that place the operative site above the right atrium carry an increased risk of VAE. Sudden decrease in end-tidal CO2 concentration (ETCO?), sudden hypotension/circulatory arrest and Mill wheel murmur indicate the diagnosisQ.