PH value of pelvic drainage as an early predictive factor for anastomotic leak after surgery for patients with rectal cancer

Abstract

Objective To investigate the pH value of pelvic drainage via sequential determination in the identification of increased risk of anastomotic leak (AL) after anterior resection for rectal cancer with a double stapling technique. Methods The daily postoperative pH values (determined at 25 ℃) of pelvic drainage in 753 consecutive patients with rectal cancer who initially underwent anterior resection with a double stapling technique were reviewed. All patients experienced a total mesorectal excision. Patients with AL (AL group, n=57) were compared to those without AL (nAL group, n=696). Mean postoperative values of drainage pH were compared. Results The diagnosis of AL was made between the 6th and 12th postoperative day (POD; mean 8th POD). There was no significant difference in the daily mean values of pH on POD 1 & 2 in group AL while a significantly sharp decline of mean pH value reached its diagnostic point of AL (P=0.000) on POD3. The cut-off value of 6.978 on the 3rd POD maximized the sensitivity (98.7%) and specificity (94.7%) of draining pH value in assessing the risk of leak. Conclusion An early and persistent decline of pH value of pelvic drainage after rectal surgery with anastomosis may be a marker of AL, which is much earlier than the regular ways. Key words: Colorectal cancer; Anastomotic leak; pH value