P-OGC07 The Role of Carbohydrate Loading on Lactate and Glucose Levels in Upper GI Cancer Surgery

Abstract

Background Surgical stress is a significant factor in metabolic dysregulation in the perioperative setting. Its impact on insulin resistance is regarded as one of the most detrimental effects, contributing to post-operative complications and poor outcomes. Clinical markers of this include glucose and lactate levels, with hyperglycaemia and hyperlactataemia the predicted responses by the body. One way of minimising the impact of surgical stress is pre-operative carbohydrate loading, which in theory will provide more substrate for metabolism. Our aim was to investigate whether carbohydrate loading had any impact on lactate and glucose levels in patients undergoing upper gastrointestinal cancer resections. Methods A retrospective observational feasibility study was performed looking at 42 patients who had undergone either an oesophagectomy or gastrectomy. Patients were divided depending on whether they received pre-operative carbohydrate loading. Lactate and glucose levels both intra-operatively and post-operatively were collected. Mean difference was compared between the two groups at 4 hours intra-operatively, 2 hours post-operatively and 12 hours post-operatively using unpaired t tests, with significance at P < 0.05. Variance between the two groups was analysed. Secondary outcomes included analysis based on type of operation, anastomotic leaks, and post-operative intravenous fluid use in the first 24 hours. Results There was no statistically significant difference in lactate levels between the two test groups at any time point. Mean difference at intra-operative 4 hours 0.0408mmol/L (+/- 0.2537, P = 0.8731); post-operative 2 hours 0.2697mmol/L (+/- 0.3008, P = 0.3754); post-operative 12 hours 0.2327mmol/L (+/- 0.2368, P = 0.3318). Glucose levels at the same time points were not significantly different: intra-operative 4 hours 0.068mmol/L (+/- 0.5322, P = 0.5746); post-operative 2 hours -0.2649mmol/L (+/- 0.4679, P = 0.5746); post-operative 12 hours 0.3773mmol/L (+/- 0.3629, P = 0.305). Secondary outcomes did not show any statistically significant differences between analysed groups. Conclusions Pre-operative carbohydrate loading does not seem to influence lactate or glucose levels in these patients either intra-operatively or post-operatively. The lack of significant differences between the two cohorts may be due to underpowering of the sample size, as this is a small feasibility study. We assume that carbohydrate loading would reduce insulin resistance and therefore lactate and glucose levels. However, could it be that carbohydrate loading is not having as much of an effect on patient metabolism as we think? A larger prospective study is recommended to investigate its impact on clinical biochemistry and patient outcomes.