A Comparative Evaluation of Nebulized Dexmedetomidine and Nebulized Ketamine as a Premedication in Pediatric Surgeries

This prospective double-blind randomized controlled study will be carried out in Tanta University Hospitals in Anesthesia Department from July 2021 to december 2021 on pediatric patients undergoing surgeries.

A written informed consent will be obtained from all patient parents who will receive an explanation to the purpose of the study and will have a secret code number to ensure privacy to participants and confidentiality of data.

Research results will be only used for scientific purposes. Procedures will be approved by both the Institutional and the Regional ethical committees.

Any unexpected risk appears during the course of the research will be cleared to the participants and ethical committee on time and proper measures will be taken to overcome or minimize these risks.

Randomization will be performed using the sealed opaque envelope technique; each patient's parent randomly selected a sealed envelope containing a group number in which the patient will be enrolled.

The sample size was calculated based on the following criteria:

• 95% confidence limit.
• 95% power of the study.
• The groups ratio is 1:1:1
• Based on a previous study , 18 patients in each group should be sufficient to detect a difference between means of the Ramsay sedation scale of 0.6 and a common standard deviation of 0.48.
• 2 cases were added to each group to overcome dropout. Therefore, we will recruit 20 cases in each group.

Anesthetic management: Preoperative assessment:

Which will include:

1. History : Clinical information such as age, gender, weight and other comorbidities will be evaluated. Take an 'AMPLE' history (allergies, medications, past medical/ anesthesia history, last meal, events leading up to the presentation), and ask about family history of problems with anesthesia.
2. Clinical examination Detailed airway assessment will be done.
3. Laboratory investigations Complete blood picture , bleeding time and clotting time . *All patients will be fasting for 2hr for clear fluids and 6-8 hr for solids.

Premedication:

In PACU, All the children will be monitored for heart rate, pulse oximetery and non-invasive blood pressure. All the baseline parameter will be observed and recorded.

Randomization:

Using sealed envelopes, patients will be assigned randomly to three groups (n=20 /group) that receive nebulized dexmedetomidine (3 μg/kg; group D) , nebulized ketamine (3mg/kg; group K) , control group (nebulized normal saline without drug: group C) .The drugs will be prepared in 0.9% normal saline to a final volume of 3ml. Nebulization will be performed using a wall nebulizer and wall oxygen source on 4 l/min . A Research nurse who will not participate in the evaluation of sedation administered the drugs to all children in nebulizer sessions ∼30 min before transfer to the OR.

Patients will be assessed for sedation score then separated from their parents and the ease of separation will be recorded.

In the OR:

Children will receive standard monitoring, including ECG, capnogram, noninvasive arterial blood pressure measurement and pulse oximetry.

Induction:

Induction of anesthesia will be done by inhalation of 8% sevoflurane in 100 % oxygen by anesthesia circuit, followed by the establishment of an intravenous peripheral line then i.v. fentanyl (1μg/kg) and atracurium (initial dose 0.5 mg/ kg) will be given and endotracheal tube will be inserted. Anesthesia will be maintained with 2% sevoflurane in a mixture of 50% air and 50% O2 to keep the end-tidal carbon dioxide pressure (PaCo2) between 30 and 35 mmHg and maintainence dose of atracurium (0.1 mg/ kg). When the surgery will end , sevoflurane discontinue, and residual neuromuscular blockade will be antagonized with IV atropine 0.02 mg/kg and IV prostigmine 0.05 mg/kg then tracheal extubation will be done and recovery time will be recorded. All patients will be transferred to PACU after tracheal extubation and discharge time will be recorded.