Absorption of carbon dioxide during endoscopic vein harvest

OBJECTIVES: Carbon dioxide (CO2) 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 CO2 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 CO2 system rather than a sealed system might be asso-ciated with different CO2 absorption during the procedure. METHODS: Patients were randomized into two groups: those patients in the first group were submitted to endoscopic vein harvest using a sealed CO2 insufflation; in the second group, the harvest was undertaken with an open CO2 insufflation. Partial pressure of CO2 in the arterial blood (PaCO2) and end-tidal CO2 (ETCO2) was recorded following anaesthesia induction and before the endoscopic pro-cedure (T0), every 10 min during the endoscopic step (T1) and end after 10 min from the CO2 insufflation termination (T2). RESULTS: A total of 60 patients were enrolled. PaCO2 increased significantly between T0, T1 and T2 in both groups (P = 0.0001) during the endoscopic harvest, but the PaCO2 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 CO2 measured at the same intervals between groups were detected. CONCLUSIONS: 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 CO2 concentration at the end of the procedure compared with the open ones