Glycocalyx Levels in Patients Undergoing Pancreatectomy

Overview

Background: On the surface of every healthy cellular membrane resides a layer known as the glycocalyx. This structure consists of extracellular domains of receptor, adhesion and transmembrane molecules such as syndecan-1 covalently bound to highly negatively charged glycosaminoglycans, heparan sulfates. It has a principal role to maintain wall integrity, avoid inflammation and tissue oedema in vessels but in contrast, glycocalyx is robust and elevated on cancer cells. This study examines whether the endothelial glycocalyx layer is preserved in patients undergoing pancreatectomy with human albumin 5% vs. gelofusine in a restrictive goal directed fluid regime perioperatively for the first 24hours. Degradation of glycocalyx will be investigated by analyzing basic levels of the core protein syndecan-1 and heparan sulfates with post-operative samples.

This is a prospective study that will be conducted in the Main Operating theatres of UMMC on patients with pancreatic cancer undergoing elective pancreatectomy (includes all forms of pancreatectomy such as Whipple's procedure, total or distal pancreatectomy). This study aim to determine the association of glycocalyx degradation by measuring levels of syndecan-1 and heparan sulfate with type of colloidal fluid given, human albumin 5% versus gelofusine in a restrictive goal directed fluid therapy in pancreatectomy. Institutional ethics approval and registration in Clinical Trial Registry will be obtained before recruiting the first case. Recruited patients will be randomly allocated to either the group receiving human albumin 5% or gelofusine. Sample size: There is no previously published literature related exactly to the pathology and methods of this proposed study. Therefore, a preliminary sample size calculation will be based on the closest study on fluids with a two-sided confidence interval of 0.95 and a desired power of 0.80 to yield a result that investigators need nine patients in each group. After adjusting for drop out rate of 10%, investigators will recruit ten in each group for human albumin 5% and gelofusine respectively within the study period of 2 years. Data collection: 1. Intraoperative phase All preoperative preparation including fasting will be done in accordance to UMMC protocol. Intraoperative monitoring includes standard routine monitoring as per American Society of Anaesthesiologist Guidelines, invasive haemodynamic monitoring with arterial blood pressure incorporating FloTrac, BIS and neuromuscular monitoring. All patients will be under general anesthesia. Fluid management for both groups are in accordance to goal directed therapy and guided by stroke volume variation of approximately 12-15%. If SVV is \> 15%, 250ml of fluid replacement according to patient group will be given over 30 min within 24 hours intra and post operatively in the Intensive Care Unit (ICU). In both groups, all clinical parameters and fluids including blood that will be given will be recorded. 2. Post-operative phase: The allocated colloid fluid will be continued. Patients will be assessed for pancreatic fistula leak. The grading of pancreatic fistula will be defined according to the guideline of Revised 2016 International Study Group on Pancreatic Fistula (ISGPF). Reviews will be done on post op days 1, 3, 5 and 30. Amylase levels from drain tube post-op Day 3, 5 and 7 will be measured. The total duration of stay in intensive care, hospital and rate of mortality/ morbidity (re-laparotomy/ re-admission to ICU/ sepsis) within 30 days after surgery will be assessed and recorded. 3. Laboratory phase Blood samples are collected at 5 time points, a) preoperative, b) immediate postoperative and c) 24 hours postoperative d) Day 3 and e) Day 7 postoperative from both groups. The serum fraction will be frozen and stored at -80°C until assayed. Syndecan 1 concentrations and heparan sulfate concentrations are quantified using special enzyme-linked immunosorbent assay kit as previously reported. Inflammatory markers Interleukin-1 and CRP and any blood investigations as per hospital sepsis protocol will be determined as well.