Correlation between CO(2) storage at the last minute of gas insufflation and area of retroperitoneal lacuna during retroperitoneal laparoscopic radical nephrectomy

BACKGROUND: Adequate operation interspace is the premise of laparoscopy, and carbon dioxide (CO(2)) was an ideal gas for forming lacuna. A retroperitoneal space is used to form operation interspace in retroperitoneal laparoscopic radical nephrectomy by making ballooning, and the retroperitoneal space has no relative complete and airtight serous membrane, therefore CO(2) absorption may be greater in retroperitoneal than transperitoneal laparoscopic radical nephrectomy. Excess CO(2) absorption may induce hypercapnemia and further cause physiopathological change of respiratory and circulatory system. Therefore, exact evaluation of amount of CO(2) which is eliminated from body via minute ventilation is important during retroperitoneal laparoscopic radical nephrectomy. The aim of the paper is to study the correlation between CO2 storage at the last minute of gas insufflation and area of retroperitoneal lacuna during retroperitoneal laparoscopic radical nephrectomy. METHODS: Forty ASA I/II patients undergoing retroperitoneal laparoscopic radical nephrectomy were enrolled. CO(2) storage at the last minute of gas insufflation and area of a retroperitoneal lacuna were observed. Linear correlation and regression were performed to determine the correlation between them. RESULTS: There was positive correlation between CO(2) storage at the last minute of gas insufflation and area of retroperitoneal lacuna (r = 0.880, P = 0.000), and the equation of linear regression was y = −83.097 + 0.925x (R(2) = 0.780, t = 11.610, P = 0.000). CONCLUSIONS: Amount of CO(2) which is eliminated from body via mechanical ventilation could be calculated by measuring the area of retroperitoneal lacuna during retroperitoneal laparoscopic radical nephrectomy, and an anesthetist should be aware of the size of lacuna to predict high CO(2) storage at the last minute of gas insufflation.