Randomized clinical trial of the influence of intraperitoneal local anesthesia on pain after laparoscopic colectomy

INTERVENTION: There are three groups in total: Group I(infiltration), Group D(Double0, Group C( Control). Group I(Infiltration) : infiltration ropivacaine only at the beginning of the surgery Group D(Double) : infiltration ropivacaine twice during the surgery (time of start and end of surgery) Immediately after creation of pneumoperitoneum and place of the first two trocars 1 mg/kg of ropivacaine in 100 ml normal saline in Group I and Group D will be sprayed on the upper surface of right and left lobe of liver and left hemidiaphragm. At the end of the operation and before withdrawing the first trocar, 100ml normal saline in Group I and 1 mg/kg of ropivacaine in 100 ml normal saline in Group D will be sprayed on the upper surface of right and left lobe of liver and left hemidiaphragm in Group D. This is one off treatment. CONDITION: the patients undergoing laparoscopic colectomy PRIMARY OUTCOME: Patients will be assessed for pain using a visual analogue pain scale (VAS) ; A VAS is a measurement instrument that tried to measure a characteristic or attitude that is believed to range across a continuum of values and cannot easily be directly measured. It is usually a horizontal line, 100 mm in length, anchored by word descriptors at each end; left side end which represents 0 is 'No pain', right side end with 100 is 'Very severe pain'. The patient marks on the line the point that they feel represents their perception of their current state. The VAS score is determined by measuring in millimeters from the left hand end of the line to the point that the patient marks. SECONDARY OUTCOME: nausea and vomiting PCM (patient controlled module :Number of attempt patient try to receive analgesics using PCA machine) of the PCA machine will be assessed The opioid consumption of the patients controlled analgesia (PCA) and additional opioid will be assessed INCLUSION CRITERIA: Patients will be scheduled to undergo elective laparoscopic colectomy.