This is prospective double-blinded placebo-randomized controlled trial that aims to compare the effect of preoperative administration of oral duloxetine 60 mg on decreasing the incidence of postoperative delirium in cancer patients undergoing surgery.

This is prospective double-blinded placebo-randomized controlled trial that aims to compare the effect of preoperative administration of oral duloxetine 60 mg on decreasing the incidence of postoperative delirium in cancer patients undergoing surgery.

The participating patients will be randomly allocated using computer generated randomizer program (http://www.randomizer.org) into 2 study groups . Duloxetine group (Group D): patients received oral duloxetine 60 mg 2 hours just before operation. Control group (Group C): patients received an identical placebo pill 2 hours just before operation

Interventions:

The preoperative anaesthetic assessment will be carried out including patient medical history , examination including baseline heart rate and blood pressure recording and review of patients' CBC , coagulation profile and chemistry investagations. In the operating room in all patients a large bore IV access (18 gauge) will be inserted.

All patients will be connected to standard routine monitoring ( non-invasive blood pressure , electrocardiography and peripheral oxygen saturation) . patients will undergo surgery under general anasthesia [ induction with IV anaesthetics (propofol 2mg/kg ) , atracurium 0.5mg/kg and maintenance with inhalational anesthesia (sevoflurane and isoflurane ). patients will be transferred to ICU after surgery . CAM-ICU will be measured every eight hours (three times a day) until the patient wiil be discharged from the ICU. Positive CAM-ICU will be considered to be delirium.

Data collection:

Pre-operative data included: age, sex, ASA classification, smoking, tumor location , tumor stage, and history of medical disease. Intra-operative data included: duration of operation, blood loss, blood and fluid transfusion. Post-operative data included: length of hospital stay, and condition on discharge (living/dead).

Sample size:

Based on determining the main outcome variable, the estimated minimum required sample size is 42 patients (21 in each group).

The sample size was calculated using G*power software 3.1.9.2., based on the following assumptions:

Main outcome variable is the variation in CAM-ICU score used to evaluate postoperative delirium in cancer surgery patients who were administered preoperative duloxetine compared to those who received a placebo. Although no prior research has examined the impact of duloxetine on delirium, one study indicated that its use resulted in a considerably better postoperative recovery outcome than that of a placebo.(Hetta et al., 2020) Main statistical test is one-sided t-test to detect the difference between the two groups, Alpha = 0.05, Power = 0.80, Effect size = 0.8, Allocation ratio= 1

Statical analysis:

Data will be analyzed using IBT SPSS advanced statistics version200(spss inc,Chicago , il) . Numerical data will be expressed as mean and standard deviation or median and range as appropriate. Qualitative data will be expressed as frequency and percentage chi-square test(fisher's exact test) will be used to examine. The relation between qualitative variables for quantitative data, comparison between two groups will be done using independent sample test or Mann Whiteny test . a P value 0.05 was considered statistically significant.](streamdown:incomplete-link)

Inclusion Criteria:

• All patients will sign an informed consent prior to inclusion in the study.
• Adult patients with ASA class I-III, undergoing cancer surgery.

Exclusion Criteria:

• Patients with pre-existing neuro- cognitive dysfunction.
• Documented signs of dementia after psychiatric evaluations.
• Language barriers or deafness.
• Psychosis stroke, meningitis, or brain tumors

The participating patients will be randomly allocated using computer generated randomizer program (http://www.randomizer.org) into 2 study groups .