Magnesium sulfate has many mechanisms of action for attenuating the stress response as inhibition of catecholamine releasing from the adrenal medulla, keeping the plasma concentration of epinephrine at a fixed level, decreasing the circulating norepinephrine level when compared to that of a control group[ and also has a vasodilation effect on systemic and coronary blood vessels by blocking calcium ion in vascular smooth muscle.-Methyl- D-Aspartate (NMDA) antagonism is an amazing recent discovery for magnesium sulphate to play an important role in stress response.

In this study, we will study the effects of nebulized magnesium sulfate on hemodynamics during intubation.](streamdown:incomplete-link)

Inclusion criteria

• 20-50 years old
• ASA: 1, 2
• Elective fit laparoscopic cholecystectomy Exclusion criteria
• Patient refusal
• patients with history of hypersensitivity to magnesium sulphate
• patients with coronary ischemic disease, atrioventricular block of any degree, known cardiac arrhythmias, heart failure
• on beta blockers or calcium channel blockers
• expected difficult intubation (Mallampati 4)
• Body mass index > 40

Study tools:

Following institutional ethical committee approval and written informed consent,a prospective randomized double-blinded study. After written informed consent wil be given, 100 patients, ASA 1 or 2, aged between 20 - 50 years, scheduled for elective surgery with Orotracheal Intubation (OTI) will be assessed for eligibility. Patients will be recruited in the study divided into two equal groups; Patients in Group A: will receive nebulized magnesium sulfate in 3 ml (240 mg) over 15 min, While group B: will receive nebulized normal saline in 3 ml over 15 min, ending 5 min before the induction of anesthesia. SBP, DBP, HR, and blood glucose level will be measured at the following intervals; Baseline (before induction), after premedication (sedation), after induction, after ETT intubation, 3 min later, 6 min later.

Full monitoring data (Blood pressure every 3 minutes, ECG, Nanogram, and pulse oximeter) wil be collected till 6 minutes then every 5 minutes. Random blood sugar will be tested 5 minutes pre-intubation, 3minutes and 5 minutes after intubation.

After end of nebulization, sedation with 2 mg midazolam and IV fluids (10 ml/kg) will be infused to avoid tachycardia of dehydration and fear of surgery. Then, we proceed on general anesthesia through propool titration + fentanyl 100 mcg + Cisatracurium 0.15 mg/kg. Endotracheal intubation with cuffed tube and mechanical ventilation with mild increase in respiratory rate 14-16/min to overcome CO2 peritoneal insufflation. All patients will receive intraoperatively, nalbuphine 0.1 mg/kg + ketorolac 60 mg + paracetamol IV 1 g. Dexamethasone 4mg + Ondansetron 4mg will be received to all patients for prophylaxis against postoperative nausea and vomiting. After end of surgery, cessation of inhalational anesthesia and reversal of muscle relaxation with neostigmine 2.5 mg+ Atropine 1mg will be done.

Consumption of isoflurane intraoperatively will be recorded. Post operative assessment for pain using VAS score will be assessed 2 hours after recovery.

Time for recovery after stop of isoflurane will be estimated.

Inclusion Criteria:

• 20-50 years old
• ASA: 1, 2
• Elective fit laparoscopic cholecystectomy

Exclusion Criteria:

• -Patient refusal
• patients with history of hypersensitivity to magnesium sulphate
• patients with coronary ischemic disease, atrioventricular block of any degree, known cardiac arrhythmias, heart failure
• on beta blockers or calcium channel blockers
• expected difficult intubation (Mallampati 4)
• Body mass index > 40

the participant will not know whither a magnesium sulfate inhalation or distilled water in the vaporizer