The use of antioxidant agents in the prevention or decreasing the severity of postoperative systemic inflammatory response syndrome after colonic surgeries adopted nowadays. Therefore, it is of interest to investigate safety and efficacy of administrating short term intravenous (IV) N acetyl cysteine as add on to l alany l glutamine and total parenteral nutrition on the marker of oxidative stress malondialdehyde and anti- inflammatory marker tumor necrosis factor alpha in patients undergoing colonic surgeries through a prospective, randomized, double blinded, controlled clinical trial

A prospective, randomized, double blinded, controlled clinical trial will be carried out on 60 patients, who will admit to the critical care unit, Ain Shams hospitals, Cairo, Egypt, following colon surgeries. Before the start of the study, eligible patients were randomized using computer generated list in order to allocate participants to either Group I (n acetyl cysteine group) or Group II (control group) in an equal manner No medication will take before the surgery and only oral fluids were allowed on the day before the operation. All eligible patients underwent bowel preparation with oral 1.745 g/ 30 ml magnesium citrate, and phosphate containing enema on the day before surgery. All patients received the general anesthesia with endotracheal intubation and muscle relaxant.

Data management and analysis were performed using the Statistical Package for Social Sciences (SPSS) software for Windows version 18

Inclusion Criteria:

• need for ICU admission after colonic surgery
• requirement of total parenteral nutrition for at least 5 days due to failure of or contraindication for enteral nutrition
• signing a written informed consent.

Exclusion Criteria:

• patients with persistent hemodynamic instability (systolic blood pressure <80 mm Hg), renal impairment, hepatic insufficiency, severe or uncontrolled sepsis, persistent metabolic acidosis, head trauma,and heart failure
• any sensitivity to components of L-alanyl L-glutamine (Dipeptiven®, Fresenius Kabi, Germany) or N acetyl cysteine

All the individual participant data will be stored on the computer and will be available on request only

it will be available once the trial ends, and for 3 months after publication

data will be available on request