Background: The authors have reported that carbon dioxide (CO(2)) insufflation is safe and effective for lengthy endoscopic submucosal dissection (ESD) with the patient under conscious sedation. However, CO(2) monitoring has not been assessed to clarify whether partial pressure of carbon dioxide (PCO(2)) increases during this type of long procedure. This study aimed to monitor CO(2) before, during, and after ESD to investigate whether CO(2) insufflation is safe for patients receiving a lengthy ESD of early colorectal neoplasia under conscious sedation.
Methods: This study prospectively enrolled 35 consecutive patients who underwent ESD at the National Cancer Center Hospital. Transcutaneous PCO(2) (PtcCO(2)) was measured with a noninvasive sensor before, during, and after ESD for patients under conscious sedation using midazolam.
Results: The mean size of removed lesions was 44 ± 22 mm (range, 15-100 mm). The operation time was 90 ± 100 min (range, 15-600 mm). The dose of midazolam was 5.7 ± 4.0 mg (range, 2-19 mg). The mean PtcCO(2) was 41 ± 5 mmHg (range, 33-53 mmHg) before ESD and 44 ± 6 mmHg (range, 32-54 mmHg) afterward. The mean peak PtcCO(2) during ESD was 55 ± 7 mmHg (range, 39-78 mmHg), which was significantly higher than before or after ESD (p < 0.0001). However, no complication associated with CO(2) insufflation such as CO(2) narcosis, gas embolism, or arrhythmia needing treatment was seen in any of the cases.
Conclusions: This study suggests that CO(2) insufflation is safe for patients receiving a lengthy colorectal ESD under conscious sedation.