Effect of endotracheal tube size on airway resistance and dynamic lung compliance

There are different results on the effect of endotracheal tube (ETT) size on respiratory mechanics in patients undergoing mechanical ventilation, and there are few reports in adult laparoscopic surgery. The aim of this study was to investigate the effect of ETT size on airway resistance (RAW) and dynamic lung compliance (COMPL) in patients undergoing laparoscopic colorectal surgery. Seventy-two patients undergoing laparoscopic radical surgery for colorectal cancer under general anesthesia with endotracheal intubation were selected and divided into 3 groups (n = 24) using the random number table method Group A (ETT ID 7.0), Group B (ETT ID 7.5), and Group C (ETT ID 8.0). After mechanical ventilation, intraoperative RAW and COMPL were monitored in each of the 3 groups. In the non-pneumoperitoneal state, RAW in group ID7.0 is significantly higher than this in group ID7.5 and group ID8.0 (P < .05); the RAW between the 2 groups with ID7.5 and ID8.0 was not statistically significant (P > .05). The difference of COMPL between the 3 groups was statistically significant (P < .05); the COMPL of Group ID7.0 is lower than Group ID7.5, and Group ID7.5 is lower than Group ID8.0. In the pneumoperitoneal state, the RAW between ID7.0 group and ID8.0 group was statistically significant, the RAW difference between ID7.0 group and ID7.5 group, ID7.5 group and ID8.0 group not statistically significant (P > .05);the COMPL between the 3 groups was not statistically significant (P > .05). In the non-pneumoperitoneal state, the smaller the ETT internal diameter within a certain range, the higher RAW and the lower COMPL; in the pneumoperitoneal state, the RAW with the ID7.0 ETT was higher than that with the ID8.0 ETT, and the ETT size within a certain range had no effect on COMPL.