Absorption of carbon dioxide during endoscopic vein harvest

Carbon dioxide (CO(2)) insufflation was used by some devices for endoscopic vein harvest to create a subcutaneous tunnel and facilitate the vein harvest. In the literature, some cases of CO(2) micro- and macro-embolisms or hypercarbia during this procedure are described. The purpose of this study was to evaluate if the use of an open CO(2) system rather than a sealed system might be associated with different CO(2) absorption during the procedure.

Patients were randomized into two groups: those patients in the first group were submitted to endoscopic vein harvest using a sealed CO(2) insufflation; in the second group, the harvest was undertaken with an open CO(2) insufflation. Partial pressure of CO(2) in the arterial blood (PaCO(2)) and end-tidal CO(2) (ETCO(2)) was recorded following anaesthesia induction and before the endoscopic procedure (T0), every 10 min during the endoscopic step (T1) and end after 10 min from the CO(2) insufflation termination (T2).

A total of 60 patients were enrolled. PaCO(2) increased significantly between T0, T1 and T2 in both groups (P = 0.0001) during the endoscopic harvest, but the PaCO(2) level was significantly higher in the group that used the sealed system (44.5 ± 7.9 vs 39.7 ± 7.9 mmHg) at the end of the procedure (P = 0.01). No significant differences between end-tidal CO(2) measured at the same intervals between groups were detected.

There was a constant increase in the blood gas concentration compared with the basal pre-procedure values. Sealed systems were associated with a significantly higher CO(2) concentration at the end of the procedure compared with the open ones.