CO₂ during single incisional thoracoscopic bleb resection with two-lung ventilation

Background: CO₂ insufflation could provide a better surgical field during single-incision thoracoscopic surgery (SITS) with small tidal two-lung ventilation (ST-TLV). Here we compared the surgical field and physiological effects of ST-TLV with and without CO₂ during SITS. Methods: Patients underwent scheduled SITS bullectomy. Surgery under ST-TLV general anesthesia performed without CO₂ (group NC) or with CO₂ insufflation (group C). The surgical field was graded at thoracoscope introduction and at bulla resection as follows: good (more than half of the 1st rib visible; bleb easily grasped with the stapler), fair (less than half of the 1st rib visible; some manipulation needed to grasp the bleb with the stapler), or poor (1st rib non-visible; bleb ungraspable). Vital signs, arterial blood gas analysis (ABGA), and mechanical ventilation parameters, postoperative chest tube indwelling duration, length of hospital stays, and complications were recorded. Results: A total of 80 patients were ultimately included. The surgical field at thoracoscope introduction was better in group C (P=0.022). However, at bleb resection, the surgical fields did not differ (P=0.172). The operation time was significantly longer in group C (P=0.019) and anesthesia recovery time was not different (P=0.369). During the CO₂ insufflation, the airway pressure was higher in group C (P=0.009). Mean PaCO₂ was significantly higher (P=0.012) and mean PaO₂ was significantly lower (P=0.024) in group C, but both values were within the physiologically normal range. Postoperative chest tube indwelling duration and length of hospital stays were not statistically different (P=0.234 and 0.085 respectively). Postoperative complication frequencies were similar (12.5% for group NC, 10.0% for group C, P=0.723). Conclusions: SITS with CO₂ insufflation during ST-TLV did not produce a superior surgical field except at the beginning of surgery. CO₂ insufflation required more time and resulted in higher mean PaCO₂ and peak airway pressure.