Arterial oxygen partial pressure and cardiovascular surgery in elderly patients

Arterial blood gas assessment is still routinely performed in candidates for a cardiovascular surgery. Whether sampling arterial blood is useful in an elderly patient with a near normal lung function and who meets all other criteria for operability, is unknown. Therefore, it was our purpose to provide reference values for arterial blood gases in these patients and to examine how the level of arterial oxygen partial pressure (PaO₂) might influence postoperative outcome. We retrospectively studied arterial blood gases in 201 patients, aged 2 70-92 years with normal or near normal ventilatory function awaiting a planned cardiovascular surgery. PaO₂ averaged 81.6±7.6 mmHg 2 and PaCO₂ averaged 37.7±3.2 mmHg. Both were independent of age. Factors associated with mortality according to bivariate analysis 2 were: gender (female), type of surgery (valve replacement), and a low PaO₂ with strictly no ventilatory abnormality. In conclusion, PaO₂ values in elderly patients with cardiac disease and normal ventilatory function are greater than those obtained by extrapolation from healthy younger subjects. PaO₂ measurement should be recommended prior to cardiovascular surgery in elderly patients since a low PaO₂ with strictly normal ventilatory function is significantly associated with an increased risk for postoperative mortality.