Early and reliable indication of air embolisms during anaesthesia can be obtained by continous monitoring of:
Capnography: It is the continuous measurement of end tidal CO2 and its waveforms. It works on the principle that infrared light is absorbed by CO2. Useful in diagnosing pulmonary embolism by air, Fat or thrombus (sudden fall in End-tidal CO2 occurs). It may become zero if the embolus is large enough to block pulmonary circulation. Ref:Sabiston 20th edition pgno: 296
ECG
Blood Pressure
End-tidal CO2
Oxygen Saturation
Cardio thoracic surgery  