Ketamine and propofol have been used most frequently agents and remifentanil is used with increasing frequency in recent years. Investigators will compare ketamine-propofol and ketamine-remifentanyl effects on drug consumption, respiration, hemodynamics and recovery in pediatric colonoscopy patients. Our study is a prospective, randomized comparison of ketamine-propofol and remifentanyl-propofol for sedation in pediatric patients during elective colonoscopy. ASA I-II, 2-16 years old, seventy children will be included in the study after ethics committee approval and written informed consent from the parents. Children with cardiovascular, cerebral, pulmonary, renal and hepatic diseases will be excluded from the study. Group I (RK); 2 mg/kg ketamine and 0,25 µg/kg remifentanyl will be administered for induction in 1 minute.Then 0,1 µg/kg/h remifentanyl infusion will be started.

Group II (PK); 2 mg/kg ketamine and 1 mg/kg propofol will be administered for induction and then 1 mg/kg/h propofol infusion will be started. In case of movement, crying, heart rate and systolic blood pressure more than 20% increase from baseline; 0.05 to 0.1 mg / kg of remifentanil will be administered in group I, 0.5-1 mg / kg will be administered propofol in group II. Not enough that case 0.5-1 mg / kg of ketamine will be applied.

The anesthesiologist will continue monitoring after completion of colonoscopy until recovery of full consciousness. A Steward recovery score of 7 will be defined as the end of the recovery time.

Optimal drug combinations for sedation and analgesia for the diagnosis and treatment of interventional procedures performed in pediatric patients still continue to be the main subject of many scientific studies. The drugs used for this purpose have advantages and disadvantages against each other. Ketamine and propofol have been used most frequently agents and remifentanil is used with increasing frequency in recent years. Investigators will compare ketamine-propofol and ketamine-remifentanyl effects on drug consumption, respiration, hemodynamics and recovery in pediatric colonoscopy patients. Our study is a prospective, randomized comparison of ketamine-propofol and remifentanyl-propofol for sedation and analgesia in pediatric patients during elective colonoscopy. ASA I-II, 2-16 years old, seventy children will included in the study after ethics committee approval and written informed consent from the parents. Children with cardiovascular, cerebral, pulmonary, renal and hepatic diseases will excluded from the study. Patients will be divided into two groups randomly. Patients will fast for at least 6 hours and have an i.v. line in place for the duration of sedation and recovery. All patients will be administered 0,5 mg/kg midazolam orally for premedication 30 minutes before the procedure. Heart rate, systolic and diastolic arterial pressure, peripheral oxygen saturation, respiratory rate and Ramsay sedation scores of all of patients will recorded at baseline, after induction and every 5 minutes during the procedure by the anesthesiologist. All of the patients will receive oxygen (2-4 L/min) through a nasal cannula and 10 ml/kg/h crystalloid infusion perioperatively. The level of recovery at the end of the procedure will be evaluated by Steward Recovery Score.

Group I (RK); 2 mg/kg ketamine and 0,25 µg/kg remifentanyl will be administered for induction in 1 minute. Then 0,1 µg/kg/h remifentanyl infusion will be started.

Group II (PK); 2 mg/kg ketamine and 1 mg/kg propofol will be administered for induction and then 1 mg/kg/h propofol infusion will be started.

In case of movement, crying, heart rate and systolic blood pressure more than 20% increase from baseline; 0.05 to 0.1 mg / kg of remifentanil will be administered in group I, 0.5-1 mg / kg will be administered propofol in group II. Not enough that case 0.5-1 mg / kg of ketamine will be applied.

The anesthesiologist will continue monitoring after completion of colonoscopy until recovery of full consciousness. A Steward recovery score of 7 will be defined as the end of the recovery time. Throughout the process and during the postoperative observation, if systolic blood pressure more than 20% decrease from baseline will be applied 0,1 mg/kg ephedrine, if heart rate more than 20% decrease from baseline 0,01 mg/kg atropine will be applied.Colonoscopy time will be recorded. At the end of the procedure, the gastroenterologist will be asked to give a score in terms of ease attempt. (1=poor, 2=moderate, 3=good, 4=excellent) Adverse events will be recorded, including hypotension (decrease in blood pressure by 20% from baseline), hypertension (increase in blood pressure by 20% from baseline), bradycardia (decrease in heart rate by 20% from baseline), and hypoxia (oxygen desaturation with peripheral oxygen saturation <90%). In addition, the need for additional medication and operator satisfaction among will be compared to the among groups.

Inclusion Criteria:

• ASA I-II
• 2-16 years old children

Exclusion Criteria:

• Children with cardiovascular disease,
• Children with cerebral disorder, respiratory disease,
• Children with renal failure
• Children with hepatic failure