Characterization of Changes in Peritoneal Cells Gene Expression After Standard Versus Low Pressure Laparoscopic Cholecystectomy and Its Clinical Correlation
Phase: NA
Conditions: Peritoneal Damage
Sponsor: Fundacion para la Investigacion Biomedica del Hospital Universitario Ramon y Cajal

CHARACTERIZATION OF CHANGES IN PERITONEAL CELLS GENE 
EXPRESSION AFTER STANDARD VERSUS LOW PRESSURE LAPAROSCOPIC 
CHOLECYSTECTOMY AND ITS CLINICAL CORRELATION. 
PROTOCOL 
 
NCT03020641 
January 27, 2017 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
INSTITUTION NAME: Ramón y Cajal Hospital. Madrid, Spain. 
PRINCIPAL INVESTIGATORS: Ana Serrano and Alfonso Sanjuanbenito. 
TITLE OF THE RESEARCH PROJECT: Characterization of changes in peritoneal cells gene 
expression after standard versus low pressure laparoscopic cholecystectomy and its clinical 
correlation. 
HYPOTHESES 
We hypothesized that applying a low intraperitoneal pressure of pneumoperitoneum (≤ 
8mmHg) during laparoscopic cholecystectomy, the adverse impact on the surgical peritoneal 
environment (measured as gene expression of extracellular matrix adhesion and inflammatory 
cytokine and apoptotic index), can be minimized and probably clinical outcomes might be 
better. 
OBJECTIVES 
Primary Objective. 
To characterize the changes produced in gene expression (mRNA) levels of remodelling and 
inflammatory markers as well as to measure apoptotic index, in peritoneal tissue, after 
laparoscopic cholecystectomy with low and standard pneumoperitoneum pressures (≤ 8mmHg 
vs ≥ 12mmHg). 
The primary aim of this study is to analyse differences in those variables between both 
intraperitoneal pressure groups at different times: Before starting surgery (T0) and 60 minutes 
after surgery started. 
 Secondary Objectives. 
To analyse within groups (high and low pressure) differences between times T0 and T1  in the 
same remodelling and inflammatory physiological parameters. To analyse the effect of 
intraperitoneal pressure in outcomes (see below). 
STUDY DESIGN 
This is a prospective randomized and blinded controlled trial to assess the potential adverse 
impact of pneumoperitoneum during laparoscopic cholecystectomy on peritoneal tissue at 
two different working pressures and at two different times and to correlate it with clinical 
outcomes as well. 
STUDY GROUPS 
A. Intervention group: in all patients allocated to the intervention group laparoscopic 
cholecystectomy will be performed with pneumoperitoneum pressure (PnPr) at or 
below 8 mm Hg. To ease this goal deep neuromuscular block will be provided with 

rocuronium till the end of surgery. Neuromuscular block will be reversed with 
sugammadex at a dose of 4mg/kg.  
B. Control group: In patients allocated to this group laparoscopic cholecystectomy with 
abdominal pressure at 12 mm Hg or higher will be performed. In this group the level of 
neuromuscular block and its reversion will be done in the same way as in the 
intervention group. 
POPULATION 
Reference population: Patients undergoing elective laparoscopic cholecystectomy. 
Eligibility: Patients older than 18 years, signed informed consent, undergoing 
laparoscopic cholecystectomy for symptomatic cholelithiasis or gallbladder polyps. 
Exclusion criteria: 
- Emergency surgery. 
- Previous surgery at supramesocolic compartment. 
- Previous peritoneal inflammatory process. 
- Pregnancy or breastfeeding. 
- Patient refusal to participate in the study. 
RANDOMIZATION 
Patients will be randomly assigned to the control or intervention group according to a simple 
randomization list generated by Query v.7. Allocation will be concealed till the surgical 
intervention date using sealed opaque numbered envelopes. 
MAIN VARIABLES IN THIS STUDY ARE:  
- Inflammatory peritoneal markers: (gene expression (mRNA) levels of): 
• 
IL-1, IL-6, IL-10. 
• 
VEGF-A “vascular endotelial growth factor A”. 
• 
TNFα “tumor necrosis factor α”. 
• 
CXCL-2 “chemokine CXC lingand 2”. 
- Remodeling peritoneal markers: (gene expression (mRNA) levels of): 
• 
CTGF “connective tissue growth factor”. 
• 
MMP-9 “matrix metalloproteinase-9”. 
• 
PAI-I “plasminogen activator inhibitor-I”. 
• 
E-selectine. 
- Apoptotic index. 

SECONDARY VARIABLES ARE: 
During the intraoperative period: 
• 
Surgical Rating Score (SRS) to measure the working space during this laparoscopic 
surgery (optimal, good, acceptable, poor or very poor conditions). 
• 
The need to change initial intraperitoneal PnPr (yes/no). 
• 
Subjective sensation of the PnPr performed (standard or low) reported by the main 
surgeon (consistent vs inconsistent). 
• 
Peak inspiratory pressure and tidal volume (mmHg). 
• 
Total Co2 volume administered during pneumoperitoneum (L).  
• 
Total dose of sugammadex (mg).  
During postoperative period: 
• 
Pain measured by visual analogue scale (VAS) from 0 to 10. 
• 
Time to start oral intake (in hours). 
• 
Time to start ambulation (in hours). 
• 
Long of hospital stay (in days). 
STATISTICAL ANALYSIS 
Biomarker data will be log-transformed before data analysis to make these variables to follow 
a normal distribution. Continuous variables will be expressed as mean and standard deviation. 
Categorical variables will be expressed as numbers and proportions. Between groups 
comparisons at T0 and T1 will be made by means of t-Student test. In case of non-normal 
distribution despite log-transformation of data we used a non-parametric alternative (U-
Mann–Whitney test) instead. We will also compare within groups means differences between 
times T1 and T0. For this comparison we will use paired t-student test or McNemar test for 
normal or non-normal variable distributions respectively. Covariance analysis  will be  used to 
compare the effect of high and low pressure on parameter analysed adjusting for baseline 
value of the biomarker. Normality tests will be based on Kolmogorov- Smirnov. All analysis will 
be performed using STATA 13 (STATACorp.2013.Stata Statistical Software: Release13. College 
Station, TX: StataCorpLP).