Figure 1. Sequence of changes in end-tidal carbon dioxide (ETCO2) end-tidal nitrogen (ETN2), pulmonary artery pressures (PAP, systolic and diastolic), central venous pressure (CVP), and oxyhemoglobin saturation (SpO2) in response to air embolus. The increase in ETN2occurred before acute changes in other parameters, and the maximal decrease in ETCO2preceded maximal increase in PAP and CVP.