A Comparative Study Between Laryngeal Mask Airway and Magensium Sulphate in Attenuating Systemic Stress Response During Emergence of Patients Undergoing Supratentorial Tumours.

A Comparative Study Between Laryngeal Mask Airway and Magensium Sulphate in Attenuating Systemic Stress Response During Emergence of Patients Undergoing Supratentorial Tumours.

To evaluate the efficacy of replacement of ETT with LMA and administration of Magnesium sulphate at the end of the surgery in attenuating systemic stress response during emergence of patients undergoing supratentorial tumours

Rapid recovery from neuroanesthesia and early neurological examination are desirable in most cases.(1)Although, Systemic and cerebral hemodynamic changes caused by extubation and emergence from anesthesia may endanger neurosurgical patients and increase the risk of postoperative intracranial hemorrhage and cerebral edema and may even result in the requirement of reoperation.(2) During this phase, heart rate and arterial blood pressure increase leading to increases in cerebral blood flow and intracranial pressure.(3) Some studies have reported such hemodynamic effects in up to 50% of patients after supratentorial craniotomy.(4,5) Replacing the endotracheal tube (ETT) with laryngeal mask airway (LMA) prior to emergence from anesthesia is safe and effectively reduces the cardiovascular response.(6) The potential protective benefit of this approach has not yet been demonstrated for awakening neurosurgery patients, however.

Magnesium is the forth most abundant cation in the body and the second most abundant intracellular cation. It activates many of the enzyme systems.(7) Magnesium sulphate inhibits catecholamines release from adrenergic nerve terminals and from adrenal medulla, through blocking N-type of Ca-channel at peripheral sympathetic nerve ending so it is used to decrease the adverse cardiovascular effects during larygeoscopy and endotracheal intubation.(8) But its role in attenuating stress response during extubation is not well studied and need more research.

Inclusion Criteria:

1. ASA physical status I, II.
2. Ages between 18 and 60 years.
3. Body mass index (BMI) < 30.
4. Elective surgery

Exclusion Criteria:

1. Patients have cardiovascular, pulmonary, renal, hepatic and endocrine diseases.
2. Patients have any degree of disturbed conscious level.
3. Ages <18 or >60 years.
4. BMI >30.
5. Patients have history of allergy to Magnesium sulphate.
6. Patients have uncontrolled hypertension during preoperative assessment.
7. Patients have risk of aspiration (eg. hiatus hernia)
8. Patients have difficult airway management during intubation with direct laryngoscope or time of intubation >30 seconds.
9. Failed ventilation with LMA.
10. Emergency surgery.