Magnesium sulfate is one of the most commonly used co-analgetics. Its antinociceptive effect is related to antagonizing NMDA (N-methyl-D-aspartate) receptors of the nervous system, has an anti-inflammatory effect by reducing the concentration of IL-6 (interleukin 6) and tumor necrosis factor alpha. In adult patients, the need for morphine in the perioperative period is reduced when magnesium infusion is used. In current guidelines for treatment of acute pain in children, magnesium sulfate may be considered as a co-analgetic. However, the strength of such a recommendation is low due to the lack of reliable scientific research confirming the effectiveness of magnesium infusion in the pediatric population. The aim of this study is to evaluate the efficacy of intravenous magnesium sulfate infusion on the opioid consumption, the circulatory, metabolic and hormonal response to intubation and surgical trauma during anesthesia for laparoscopic appendectomy in children.

Pain in the perioperative period is associated with surgical stimuli but also with laryngoscopy and intubation. According to the currently applicable ERAS (Enhanced Recovery After Surgery) doctrine, the recommended method of anesthesia is multimodal, low-opioid anesthesia. The essence of multimodal anesthesia is to combine different methods (e.g. general and regional anesthesia) and various anesthetic drugs in order to reduce the intraoperative use of opioids. The one of commonly used co-analgetic is magnesium. The use of magnesium infusion before induction of anesthesia may enhance the analgesic effect of the opioid administered before intubation. In current guidelines for the relief of acute pain in children, magnesium sulfate may be considered as a coanalgesic. It is based only on expert consensus opinion and/or data from small studies, retrospective studies, registries.

According to available data magnesium sulfate is superior to placebo in decreasing analgesic consumption and pain scores during the first 48 h after operation without any adverse effects in children with cerebral pals. In other groups of pediatric patients, the effectiveness of magnesium as a co-analgetic has not been proven. High quality randomized controlled trials are still missing.

The primary outcome of this study is to assess opioid consumption during the laparoscopic appendectomy. Number of patients requiring rescue dose of opioids will be measured.

The secondary aim is to examine total intraoperative fentanyl consumption, fluctuations of heart rate and blood pressure, metabolic, hormonal and inflammatory response (glucose, cortisol and IL-6 concentrations) and occurrence of side effects that may result from magnesium intake (decrease in blood pressure, bradycardia or allergic reaction).

In the pediatric population, the optimal perioperative magnesium dosage is 50 mg/kg as a bolus followed by an infusion of 15 mg/kg/hour until the end of the operation.

The general aim of the study is to evaluate the analgesic efficacy of intravenous magnesium sulfate as an adjunct to standard general anesthesia (involving intravenous induction and opioid with sevoflurane maintenance) for intubation and surgical trauma during anesthesia for laparoscopic appendectomy in children.

Inclusion Criteria:

• ASA (American Society of Anesthesiologists) physical status class 1E, 2E, 3E (E - emergency)
• Patients undergoing laparoscopic appendectomy

Exclusion Criteria:

• Allergy to the magnesium sulfate or the excipient
• Hypermagnesemia
• Renal failure (GFR <30 ml/min)
• Myasthenia gravis
• Preoperative atrioventricular block
• Hypotension
• The use of digitalis glycosides
• The use of oral anticoagulants
• ASA physical status class 4E or higher
• Chronic treatment with analgesics
• Legal guardians or patient refusal

The datasets used and/or analysed during the study will be available from the corresponding author on reasonable request.

The study protocol will be available to other researchers continuously after its publication.

The Clinical Study Report will be published after the study completion.

The datasets used and/or analysed during the study will be available from the corresponding author on reasonable request.

The drug or placebo (normal saline) will be placed in a syringe by the principal investigator. Only principal investigator will be aware of the participants allocation. The principal investigator will not be involved in the process of: recruitment, providing an intervention, or outcomes assessment.