Physiological changes after colorectal surgery suggest anastomotic leakage is an early event: a retrospective cohort study.

INTRODUCTION: Anastomotic leakage (AL) is often identified 7-10 days after colorectal surgery. However, in retrospect, patients may have abnormalities evident much earlier. This study aims to identify the clinical time-point when AL occurs.

METHODS: This is a retrospective case-matched cohort-comparison study, assessing patients undergoing left-sided colorectal resection between 2006 and 2015 at a specialist colorectal unit. Patients who developed anastomotic leakage (LEAK) were case-matched to two CONTROL patients by procedure, sex, laparoscopic-modality and diverting stoma. Case-note review allowed collection of basic observation data and blood tests (leukocyte count, C-reactive protein, bilirubin, alanine transaminase, creatinine) up to post-operative day (POD)4. The cohorts were compared, with the main outcome measure being changes in basic observation data.

RESULTS: Of 554 patients, 49 patients developed AL. These were matched to 98 CONTROL patients. Notes were available for 105 patients (32 LEAK/ 73 CONTROL). Groups were similar in demographics, tumour or nodal status, pre-operative radiotherapy, intra-operative air-leak integrity, and drain usage. AL was detected clinically at a median of 7.5-days post-operatively. There was a significantly increased heart rate by the evening on POD1 in LEAK patients (82.8±14.2 /min-1 versus 75.1±12.7 /min-1 , p=0.0081) which persisted for the rest of the study. By POD3, there was a significant increase in respiratory rate (18.0±4.2 /min-1 versus 16.5±1.3 /min-1 , p=0.0069) and temperature (37.0±0.4C vs 36.7±0.3C, p=0.0006) in LEAK patients. C-reactive protein was significantly higher in LEAK patients from POD2 (165±95mg.L-1 versus 121±75mg/L-1 , p=0.023).

CONCLUSIONS: Physiological and biochemical changes associated with AL occur very early post-operatively, suggesting AL may occur within 36 hours after surgery, despite much later clinical detection. This article is protected by copyright. All rights reserved.